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The impacts of roads and other infrastructure on mammal and bird populations: A meta-analysis
... bobcat, camera traps, dynamic occupancy models, Lynx rufus, urbanization 1 | INTRODUCTION Landcover change associated with human development is a driver of global biodiversity loss and wildlife population declines (Newbold et al., 2015). The increase of road infrastructure globally has specifically been linked to negative effects on natural ecosystems and wildlife populations (Benítez-L opez et al., 2010;Trombulak & Frissell, 2000). These effects include increased wildlife road-mortality (Bennett, 2017) and population declines (Fahrig & Rytwinski, 2009), the creation of edge and barrier effects that reduce habitat suitability and animal movement (Benítez-L opez et al., 2010;Riley et al., 2006;Shepard et al., 2008), and increased human access to natural areas (Benítez-L opez et al., 2010;Červinka et al., 2015;Forman & Alexander, 1998). ...
... The increase of road infrastructure globally has specifically been linked to negative effects on natural ecosystems and wildlife populations (Benítez-L opez et al., 2010;Trombulak & Frissell, 2000). These effects include increased wildlife road-mortality (Bennett, 2017) and population declines (Fahrig & Rytwinski, 2009), the creation of edge and barrier effects that reduce habitat suitability and animal movement (Benítez-L opez et al., 2010;Riley et al., 2006;Shepard et al., 2008), and increased human access to natural areas (Benítez-L opez et al., 2010;Červinka et al., 2015;Forman & Alexander, 1998). While road surfaces and their maintained roadsides alone do not cover a large percentage of land (e.g., 1% of the landcover in the United States; Forman & Alexander, 1998), the density of roads in an area can be an indicator of the extent of the anthropogenic footprint (Forman, 2000;Forman et al., 2003;Frair et al., 2008). ...
... The increase of road infrastructure globally has specifically been linked to negative effects on natural ecosystems and wildlife populations (Benítez-L opez et al., 2010;Trombulak & Frissell, 2000). These effects include increased wildlife road-mortality (Bennett, 2017) and population declines (Fahrig & Rytwinski, 2009), the creation of edge and barrier effects that reduce habitat suitability and animal movement (Benítez-L opez et al., 2010;Riley et al., 2006;Shepard et al., 2008), and increased human access to natural areas (Benítez-L opez et al., 2010;Červinka et al., 2015;Forman & Alexander, 1998). While road surfaces and their maintained roadsides alone do not cover a large percentage of land (e.g., 1% of the landcover in the United States; Forman & Alexander, 1998), the density of roads in an area can be an indicator of the extent of the anthropogenic footprint (Forman, 2000;Forman et al., 2003;Frair et al., 2008). ...
Human developments have detrimental effects on wildlife populations globally with carnivores being particularly sensitive. The bobcat (Lynx rufus) is often considered an adaptable mesocarnivore that occurs throughout varied landcover types within its wide distribution and may be less susceptible to the negative effects of development. Our objectives were to investigate the landscape occupancy dynamics of bobcats in a highly developed and densely populated region of the northeastern United States to evaluate the sensitivity of bobcat occurrence to natural and anthropogenic landscape features. We established a large‐scale camera trapping survey throughout Rhode Island, USA, sampling from 2018 to 2020. Using dynamic occupancy models, we found initial site occupancy was positively influenced by the amount of forested wetland habitat, while increasing road density and shrub cover negatively influenced the probability of site colonization. Surprisingly, we found no hypothesized variables to influence site‐level extirpation probability, or any seasonal effects on dynamic parameters. Lastly, we found that forest cover and road density negatively influenced the probability of detection. The probability of occupancy was high, >0.8, throughout much of the study area (49%), but we also found relatively high site transients, with the probability a site would change occurrence status from season to season at ≈0.27 in the majority of the study area (70%). Our results show that although bobcats can persist in human‐dominated landscapes, they require contiguous natural areas to do so. Future expansion of road infrastructure may reduce habitat connectivity and increase road mortalities, thus jeopardizing the population. Bobcats are widespread throughout Rhode Island, but are difficult to detect in a highly forested landscape. They are also sensitive to increasing road densities, and further urbanization and habitat fragmentation may jeopardize the population.
... While the obvious direct effect of traffic reduction is reduced wildlife mortality across multiple species (described above) by reviewing current wildlife-vehicle conflict research, we may be able to posit some additional ecological effects (Figure 2). Roadkill risk is species-specific (Benítez-López et al., 2010;Alamgir et al., 2017) with slow-moving and wide-ranging species, for example, at a high risk of road mortality as a function of their life-history traits (González-Suárez et al., 2018). The positive effects of the anthropause could therefore be expected to be greatest for those species that are most prone to WVCs, but also those whose population sizes are most impacted; typically those with low reproductive rates (Rytwinski and Fahrig, 2012). ...
... The positive effects of the anthropause could therefore be expected to be greatest for those species that are most prone to WVCs, but also those whose population sizes are most impacted; typically those with low reproductive rates (Rytwinski and Fahrig, 2012). Reduced traffic may lead to loss of "barrier effects, " isolation and/or, fragmentation of local populations which, in the longterm could be manifested as changes in gene flow and improved fitness (Figure 2; Benítez-López et al., 2010). Pollution events FIGURE 1 | Country-specific changes in monthly mean aggregated requests for directions in Apple maps, representing a proxy for traffic activity during the SARS CoV-2 pandemic in 2020/21 relative to a baseline "norm" on 13th Jan 2020. ...
... Species-specific differences in mortality risk or fitness leads back to Paine's work (Paine, 1969(Paine, , 1966, with trophic cascades a possible outcome. Some raptor species, for example, are attracted to roads (Benítez-López et al., 2010), potentially due to the availability of roadkill for scavenging (Schwartz et al., 2018). Any significant loss of biomass, in the form of roadkill, may lead to prey-switching, a biotic interaction that is acknowledged in the rewilding and invasive species literature to create ecosystem imbalance and alter evolving responses (Lurgi et al., 2018). ...
The SARS-CoV-2 pandemic severely reduced many human activities. So pronounced was the change, it has given rise to the term “anthropause”: the considerable alteration of modern human activities. Among these was surface transportation, with prolonged traffic reductions, in excess, of 50% in many countries. Roads and traffic are responsible for functionally fragmenting ecosystems, wildlife populations, and species interactions. The unintentional “dialing-down” of traffic has given continuous monitoring systems of wildlife-vehicle conflict a unique opportunity to study the consequences of perturbing this source of wildlife disturbance and mortality. Experimental manipulation of traffic at the global scale would not have been possible without mitigation responses to SARS-CoV-2. Such a perturbation allows robust empirical investigation into wildlife responses to traffic, including changes in mortality, behavior, genetic connectivity, and knock-on ecosystem effects, the responses to which can be replicated across a global network of wildlife-vehicle conflict monitoring systems. We review the extent to which these extensive data-collection systems provide the primary source of data to study many of these responses, providing the raw material to understand some striking wildlife consequences of the anthropause.
... While clear-cutting roadside sections of habitat may be repellent to some species such as small mammals, which are more greatly exposed to predators, this same action can act as an attractant to ungulates feeding on regenerating vegetation (Hurley et al., 2009;Needham et al., 2020;Nussey & Noseworthy, 2018;Rytwinski et al., 2015;Teixeira et al., 2017b;Valerio et al., 2021;van der Ree et al., 2011van der Ree et al., , 2007. Thus, collision risk factors should be considered separately for major taxa (Barnes, 2019;Benítez-López et al., 2010;Gunson et al., 2009;Rytwinski et al., 2015). Factors can be further distinguishable based on whether they are related to the road-surface or the roadside (Barnes, 2019;Benítez-López et al., 2010;Gunson et al., 2009;Rytwinski et al., 2015). ...
... Thus, collision risk factors should be considered separately for major taxa (Barnes, 2019;Benítez-López et al., 2010;Gunson et al., 2009;Rytwinski et al., 2015). Factors can be further distinguishable based on whether they are related to the road-surface or the roadside (Barnes, 2019;Benítez-López et al., 2010;Gunson et al., 2009;Rytwinski et al., 2015). Road parameters might include road curvature, speed limit, traffic density, and wildlife-crossing signs, which affect the driver's ability to detect a crossing and an animal's willingness to cross (Hurley et al., 2009). ...
... Ring Buffer tool was used along with the Roads polyline layer as an input and linear unit distances of 0.5, 1.0, and 5.0km. These were chosen in accordance with (Benítez-López et al., 2010) to accommodate the different mobility and land use categories of each functional group (Table 6). The default dissolve option was kept allowing for concentric rings dissolved into 3 regions ( Figure 5). ...
... Both the expansion of roads and increased human development threaten wildlife occupancy and mobility (Benítez-L opez et al., 2010;Crooks et al., 2017;DeMars & Boutin, 2018;Gleeson & Gleeson, 2012;Kiesecker et al., 2010;Krauss et al., 2010). However, roads and development differ in the processes by which they affect both individual species and community composition, as well as in the conservation strategies needed to mitigate their impacts (Benítez-L opez et al., 2010). ...
... Both the expansion of roads and increased human development threaten wildlife occupancy and mobility (Benítez-L opez et al., 2010;Crooks et al., 2017;DeMars & Boutin, 2018;Gleeson & Gleeson, 2012;Kiesecker et al., 2010;Krauss et al., 2010). However, roads and development differ in the processes by which they affect both individual species and community composition, as well as in the conservation strategies needed to mitigate their impacts (Benítez-L opez et al., 2010). Therefore, understanding the role of these elements in influencing wildlife distribution and community composition can better inform conservation strategy and practice. ...
... The damaging effects of roads on wildlife populations and community diversity occur over short-and long-term spatiotemporal scales (Clements et al., 2014;Crooks et al., 2017;Krauss et al., 2010). Avoidance of roads due to the lack of vegetation cover, noises, and increased exposure to vehicles prevent species from moving between habitats, causing minimal dispersal and the creation of habitat "islands" (Benítez-L opez et al., 2010;Fahrig & Rytwinski, 2009). Limited connectivity between habitats combined with reductions in habitat area can contribute to population declines and increased local extinction risk for many species (Crooks et al., 2017;Krauss et al., 2010). ...
Human development and roads threaten wildlife through distinct mechanisms and understanding the influence of these elements can better inform mitigation and conservation strategies. We used camera traps to quantify the effects of major roads, environmental factors, and human development on the mammalian community composition between sites north and south of a major interstate highway in northern Utah, USA. We found no significant differences in species richness nor community similarity across the north–south divide of the highway. Through Bayesian hierarchical modeling, we compared the effects of the distance to the highway, housing and human population density, normalized difference vegetation index (NDVI), and the human footprint index to changes in mammalian community composition and species‐specific habitat usage. Community occupancy response, similarity, and species richness were negatively affected by increased housing and human population densities and positively affected by increased NDVI and decreased human footprint, whereas their response to the highway was more inconclusive. We conclude that mammalian community composition in our study area is influenced by both environmental conditions and human development while the effect of the highway was more nuanced, possibly due to the presence of a newly constructed wildlife overpass. Taken together, the lack of differences in species richness or community composition across the highway suggests that it may not currently exacerbate the effects of other anthropogenic sources of habitat fragmentation and highlights the need for additional research into human–wildlife conflict mitigation strategies.
... Land use change and infrastructure from industrial development are increasing at an accelerated pace across all regions of the world (Venter et al., 2016;Ibisch et al., 2016), including all global biodiversity hotspots (Hu et al., 2021), and are among the main causes of biodiversity declines (Benítez-López et al., 2010;Newbold et al., 2015). Most infrastructure development takes place in areas already affected by multiple sources of disturbance (Barber et al., 2014) and, thus, infrastructure of the same type are often clustered in the landscape. ...
... Our formulation can be easily adapted to model other types of biological responses, such as population abundance (e.g. Benítez-López et al., 2010), species richness (e.g. Ficetola & Denöel, 2009) or other measures of biological diversity and ecological processes, with direct application in environmental and strategic impact assessment and integrated land use planning. ...
1. Infrastructure development often takes place in landscapes already affected by multiple anthropogenic disturbances. Typically, the impact of a given type of infrastructure is determined by computing the distance to the nearest feature only, ignoring potential cumulative impacts of multiple features on biodiversity. We propose an approach to assess whether and how multiple anthropogenic features lead to cumulative impacts. 2. We derive a method to estimate the effect size and zone of influence (ZoI) of infrastructure, that allows us to quantify the impact based on the nearest feature only and the cumulative impact of multiple features of the same type. First, we use simulations and an empirical case to understand under which circumstances the estimated cumulative ZoI cannot be distinguished from the ZoI of the nearest feature only. Second, we illustrate the approach by quantifying and visualizing cumulative impacts of recreational facilities in Norway on habitat selection of wild reindeer, a species highly sensitive to anthropogenic disturbance. 3. Simulations show the ZoI of the nearest feature and the cumulative ZoI cannot be distinguished when the occurrence of features is rare and ZoI is small, and when features are clustered and ZoI is large. In our empirical analysis we found strong evidence of cumulative impacts of private cottages and tourist resorts on reindeer, with ZoI radii of 10 and 20 km, respectively. While the impact of a single private cottage was negligible, the cumulative impact of an aggregation of cottages could be larger than that of a tourist resort. Hence, measuring only the ZoI of the nearest private cottage would underestimate the impact of the widespread phenomena of cabin villages. 4. The approach we developed allows to assess cumulative impacts of infrastructure on biodiversity, and can be broadly applied in impact assessment and land use planning. The ZoI metrics presented are computationally efficient and flexible and can be computed in R and GRASS GIS through the oneimpact R package. Although our example focuses on animal space use, the approach can be applied in environmental impact studies from individuals to populations and communities, and counter the widespread trend of underestimating anthropogenic impacts.
... The negative association of hunted forest-dependent species to anthropogenic disturbances was an expected pattern. The presence of roads and human population has been widely used as a predictor of species' vulnerability to extinction and hunting (Peres 2000, Benítez-López et al. 2010, Lima et al. 2020. The negative relationship of road density and hunted forest-dependent species reinforces the widely recognised and damaging effects of roads on mammals, since highways can facilitate human access to fragments, increase mortality due to collisions, or act as barriers to species' movements (Benítez-López et al. 2010, Caceres 2011, Espinosa et al. 2014). ...
... The presence of roads and human population has been widely used as a predictor of species' vulnerability to extinction and hunting (Peres 2000, Benítez-López et al. 2010, Lima et al. 2020. The negative relationship of road density and hunted forest-dependent species reinforces the widely recognised and damaging effects of roads on mammals, since highways can facilitate human access to fragments, increase mortality due to collisions, or act as barriers to species' movements (Benítez-López et al. 2010, Caceres 2011, Espinosa et al. 2014). In addition, hunting can be a determining factor for mammal persistence. ...
• Habitat loss and the conversion of natural environments to anthropogenic land uses are among the main drivers of biodiversity decline worldwide. The remaining habitats are inserted in highly modified landscapes, presenting contrasting patch and landscape features. Understanding species’ responses to these anthropogenic land-use changes is essential for informing conservation planning.
• We evaluate which spatial predictors (measured at the patch and landscape scales) and species’ life-history traits best predict the occurrence of medium-sized and large mammals in forest fragments of the threatened Atlantic Forest of South America.
• We gathered occurrence data for 36 medium-sized and large mammal species recorded by camera traps, distributed over 220 forest fragments spanning the entire Atlantic Forest biome. Species were classified according to their characteristics as follows: ‘hunted forest-dependent’, ‘non-hunted forest-dependent’, and ‘generalist’ species. Further, each species’ occurrence was related to spatial predictors and life-history trait variables.
• We revealed a severe defaunation of forest mammals occurring in most forest fragments in the Atlantic Forest. Landscapes containing large forest patches, low road density, and high human population density harboured high numbers of mammal species, including those exhibiting greater body mass. Nevertheless, mammal groups diverge in their sensitivity to landscape changes. Hunted forest-dependent species mainly occurred in landscapes with lower edge density and numbers of patches and with less anthropogenic disturbance, while non-hunted forest-dependent species mainly occupied large forest fragments. Finally, generalist species also occurred in landscapes with low edge density and number of patches, but were more prevalent in landscapes with higher human population density.
• We stress the importance of maintaining large forest fragments, considering the effects of landscape configuration on conservation strategies, and reducing anthropogenic disturbances to ensure a greater persistence of mammal species in the Atlantic Forest.
... Birds constitute an important component of most ecosystems of all biomes; they contribute to many ecosystem services (Millennium Ecosystem Assessment, 2003;Whelan et al., 2008), and can be useful indicators of habitat quality and biodiversity (Blair, 1999;Kati et al., 2004;Orme et al., 2005;Frederick et al., 2009;Fraixedas et al., 2020). It is well documented that birds can be both negatively and positively affected by linear infrastructure (Benítez-López et al., 2010;Rytwinski and Fahrig, 2012;Morelli et al., 2014;Ouédraogo et al., 2020), and they have been widely studied in most contexts, including road ecology. The large amount of available data means that birds represent an attractive taxonomic group for investigating different factors that may influence biodiversity in road habitats. ...
... Most woodland in our analyses was (near)natural forest, so forests that had seen low levels of human modification. It has previously been suggested that relatively undisturbed areas should be kept as intact as possible, and road-planners should focus on areas that are more homogenous as a result of higher human activity (Benítez-López et al., 2010;Ibisch et al., 2016;D'Amico et al., 2019;Ascensão et al., 2021). However, benefits of added heterogeneity may depend on specific local factors that need to be taken into consideration on a case by case basis. ...
Roadsides can harbour remarkable biodiversity; thus, they are increasingly considered as habitats with potential for conservation value. To improve construction and management of roadside habitats with positive effects on biodiversity, we require a quantitative understanding of important influential factors that drive both positive and negative effects of roads. We conducted meta-analyses to assess road effects on bird communities. We specifically tested how the relationship between roads and bird richness varies when considering road type, habitat characteristics and feeding guild association. Overall, bird richness was similar in road habitats compared to non-road habitats, however, the two apparently differ in species composition. Bird richness was lowered by road presence in areas with denser tree cover but did not differ according to road type. Richness differences between habitats with and without roads further depended on primary diet of species, and richness of omnivores was positively affected by road presence. We conclude that impacts of roads on bird richness are highly context-dependent, and planners should carefully evaluate road habitats on a case by case basis. This emphasizes the need for further studies that explicitly test for differences in species composition and abundance, to disentangle contexts where a road will negatively affect bird communities, and where it will not.
... These projects promise social and economic progress (e.g., energy, broader access to markets, health care and education) [8,9]. However, the associated negative environmental (e.g., forest fragmentation and degradation, fires and poaching) and social impacts (e.g., land grabbing, corruption, human conflicts and violence) are escalating, as environmental roll-backs promote more infrastructure and resource extraction investments [5][6][7][8][9][10][11][12][13][14][15][16]. ...
... The outcomes of such development projects are seen everywhere. For example, road construction increased migration and has led to high rates of deforestation and contentious processes [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Lack of public participation in the planning process is one of the crucial factors behind the negative outcomes of large-scale infrastructure projects; especially neglected is the participation by local communities who are directly and indirectly affected by these projects [26][27][28]. ...
The Amazon region has been viewed as a source of economic growth based on extractive industry and large-scale infrastructure development endeavors, such as roads, dams, oil and gas pipelines and mining. International and national policies advocating for the development of the Amazon often conflict with the environmental sector tasked with conserving its unique ecosystems and peoples through a sustainable development agenda. New practices of environmental governance can help mitigate adverse socio-economic and ecological effects. For example, forming a “community of practice and learning” (CoP-L) is an approach for improving governance via collaboration and knowledge exchange. The Governance and Infrastructure in the Amazon (GIA) project, in which this study is embedded, has proposed that fostering a CoP-L on tools and strategies to improve infrastructure governance can serve as a mechanism to promote learning and action on factors related to governance effectiveness. A particular tool used by the GIA project for generating and sharing knowledge has been participatory mapping (Pmap). This study analyzes Pmap exercises conducted through workshops in four different Amazonian regions. The goal of Pmap was to capture different perspectives from stakeholders based on their experiences and interests to visualize and reflect on (1) areas of value, (2) areas of concern and (3) recommended actions related to reducing impacts of infrastructure development and improvement of governance processes. We used a mixed-methods approach to explore textual analysis, regional multi-iteration discussion with stakeholders, participatory mapping and integration with ancillary geospatial datasets. We believe that by sharing local-knowledge-driven data and strengthening multi-actor dialogue and collaboration, this novel approach can improve day to day practices of CoP-L members and, therefore, the transparency of infrastructure planning and good governance.
... The relationship between the frequency of jaguars and distance to unpaved roads was not very clear. We then assumed that 5 km correspond to a road-effect zone for jaguars 48,49 both for paved and unpaved roads and the analyses were performed only for the cells located within 5 km of the roads. ...
Roads pose an imminent threat to wildlife directly through mortality and changes in individual behavior, and also indirectly through modification of the amount and configuration of wildlife habitat. However, few studies have addressed how these mechanisms interact to determine species response to roads. We used structural equation modeling to assess direct and indirect effects (via landscape modification) of roads on space use by jaguars in Brazil, using radio-tracking data available from the literature. We fit path models that directly link jaguars’ space use to roads and to land cover, and indirectly link jaguars’ space use to roads through the same land cover categories. Our findings show that space use by jaguars was not directly affected by roads, but indirect effects occurred through reductions in natural areas on which jaguars depend, and through urban sprawl. Males´ space use, however, was not negatively influenced by urban areas. Since jaguars seem to ignore roads, mitigation should be directed to road fencing and promoting safe crossings. We argue that planners and managers need to much more seriously take into account the deforestation and the unbridled urban expansion from roads to ensure jaguar conservation in Brazil.
... The development of infrastructures such as power lines, roads, wind farms and solar facilities has well-documented negative impacts on bird communities (Benítez-López et al., 2010;Bernardino et al., 2018;Kosciuch et al., 2020;Marques et al., 2014). Among those of greatest concern is direct mortality, so post-EIA monitoring programs often include regular searches of bird carcasses along or around the different infrastructures (Loss et al., 2015). ...
Environmental impact assessment (EIA) follow-up monitoring in energy projects, such as wind farms, solar facilities and power lines, frequently encompasses bird fatality surveys based on regular carcass searches. Since a large number of bird carcasses are often not found, field experiments to determine carcasses persistence (CP) and searcher efficiency (SE) biases in fatality surveys are typically performed for every single project. These data are, however, rarely used beyond the scope of each original project. We compiled data from CP and SE trials performed under 36 independent monitoring programs aiming to assess bird mortality at transmission lines in Portugal, whose results were until now unavailable or dispersed in grey literature. We used survival analysis and generalized linear mixed-effects models to investigate the ecological and methodological factors influencing CP times and SE rates. Bird carcass size was a key driving factor of both CP times and SE rates of human observers, which were consistently out-performed by scent detection dogs. Season and habitat interactions had also an important role in CP patterns, while variations in SE rates by human observers were largely influenced by ground visibility (i.e., a combination of ground cover and vegetation height). Our results reinforce previous studies indicating that CP and SE biases are site-specific and determined by a wide range of ecological and methodological factors not always accounted in standard trial designs. Overall, our study demonstrates that data routinely collected under bird monitoring programs from multiple projects can be combined to identify broad ecological patterns, limitations of current studies and, ultimately, improve EIA follow-up practice.
... Road systems generate changes in the landscape and in the territory, causing direct and indirect effects on the structure and composition of ecosystems. Some of these effects include, but are not limited to, animal roadkill, barrier effect, edge effect, dispersion of exotic species, changes in microclimates, contamination of water resources, and fragmentation of ecosystems [1][2][3][4][5][6][7]. As a consequence of the above, the loss of biodiversity has significantly increased, with vertebrate species being the most affected [6][7][8][9][10]. ...
Citation: Coitiño, H.I.; Achkar, M.; Guerrero, J.C. Prediction of Sites with a High Probability of Wild Mammal Roadkill Using a Favourability Function. Diversity 2021, 13, 585. Abstract: Roads are one of the main causes of loss of biodiversity, with roadkill one of the main causes of mortality. The aim of this research was to identify sites with a high probability of roadkill of medium and large mammals, and the environmental variables that would explain it. We used the favourability function (F) to build the predictive models. There were 57 explanatory variables, and we collected 685 records of 10 species of medium and large native wild mammals from the ECOBIO Uruguay databases. They were grouped into native forest and grassland species, according to the main habitat. Two models were developed, one with all the variables and one with the anthropogenic variables. For both groups, the model obtained with all the variables was the most significant according to the evaluation indices used. This made it possible to identify the hot spots of roadkill (F > 0.6) for each of the groups. The anthropic variables were the ones that best explained these hot spots. This allowed the identification of sites where the probability of roadkill is high and requires a monitoring plan to implement mitigation measures in the future.
... Since different studies have found that birds and mammals differ in their response to anthropogenic disturbance (e.g. Benítez-López et al. 2010, Fontúrbel et al. 2015, Sauvajot et al. 1998, we expect the magnitude of the above-mentioned effects to differ between these two groups. ...
Great attention has been drawn to the impacts of habitat deforestation and fragmentation on wildlife species richness. In contrast, much less attention has been paid to assessing the impacts of chronic anthropogenic disturbance on wildlife species composition and behaviour. We focused on natural small rock pools (sartenejas), which concentrate vertebrate activity due to habitat’s water limitation, to assess the impact of chronic anthropogenic disturbance on the species richness, diversity, composition, and behaviour of medium and large-sized birds and mammals in the highly biodiverse forests of Calakmul, southern Mexico. Camera trapping records of fauna using sartenejas within and outside the Calakmul Biosphere Reserve (CBR) showed that there were no effects on species richness, but contrasts emerged when comparing species diversity, composition, and behaviour. These effects differed between birds and mammals and between species: (1) bird diversity was greater outside the CBR, but mammal diversity was greater within and (2) the daily activity patterns of birds differed slightly within and outside the CBR but strongly contrasted in mammals. Our study highlights that even in areas supporting extensive forest cover, small-scale chronic anthropogenic disturbances can have pervasive negative effects on wildlife and that these effects contrast between animal groups.
... Deforestation and habitat degradation as a consequence of infrastructure development, including roads, mines, commercial agriculture, and hydroelectric dams, are particularly rampant in South-east Asia, where roughly 50% of the natural habitat, in particular lowland rainforests (<200 m elevation), has been destroyed over the past 20 years (Shwe et al. 2020, Namkhan et al. 2021, much higher than figures generally observed in other tropical regions (Achard et al. 2002, Sodhi et al. 2010. Human population growth (Laurance et al. 2015) has also contributed to this rapid decline in habitat quality and loss of biodiversity in the region (Seiler 2002, Benítez-Ló pez et al. 2010. Particularly critical is the situation of the lowland forest in the biodiversity-rich transition zone of the Isthmus of Kra, between the Indo-Burma and Sundaic regions in southern Thailand (Hughes et al. 2003), where more than 95% of the natural forest has been destroyed with the resident specialist birds increasingly under threat (Round 1988). ...
Habitat degradation due to hydropower development within protected areas has a marked negative effect on resident wildlife species. However, efforts to develop appropriate conservation and management plans are hampered by a general lack of quantitative information and a poor understanding of relevant ecological constraints. Great Argus Argusianus argus , a large galliform species sensitive to habitat degradation, can reflect the impacts of the Chiew Larn reservoir in southern Thailand on local wildlife. Great Argus abundance in the remaining lowland areas of Khlong Saeng Wildlife Sanctuary (KSWS) was estimated using line transects along the Chiew Larn reservoir edges and in the forest interior between February and April 2017. The population estimate for KSWS was 108 individuals (95% CI: 41–272) based on the sampled area of 18.06 km ² , with a density estimate of 5.9 calling males/km ² . The abundance increased with increased distance from the reservoir shoreline, which might be related to the high level of direct and indirect human disturbance close to the hydropower reservoir.
... Moreover, human disturbances often have indirect negative impacts on forest biodiversity (Barlow et al. 2016). For instance, opening up of continuous forests by roads causes fragmentation and increases edge effects, which threatens interior species (Young 1994), facilitates illegal hunting (Benítez-López et al. 2010), and exposes interior forests to wind storms, besides the direct effect of the removal of trees during the road construction (Laurance et al. 2009;Dissanayake et al. 2019). Still, the mere presence of humans in forest landscapes may not necessarily lead to biodiversity loss (Posey 1985), suggesting the importance of understanding the impacts of different types of human disturbances (Alroy 2017;Ahrends et al. 2021). ...
Context
Human disturbances can have large impacts on forest structure and biodiversity, and thereby result in forest degradation, a property difficult to detect by remote sensing.
Objectives
To investigate spatial variation in anthropogenic disturbances and their effects on forest structure and biodiversity.
Methods
In 144 plots of 20 × 20 m distributed across a forest area of 750 km² in Southwest Ethiopia, we recorded: landscape variables (e.g., distance to forest edge), different human disturbances, forest structure variables, and species composition of trees and epiphyllous bryophytes. We then first assessed if landscape variables could explain the spatial distribution of disturbances. Second, we analysed how forest structure and biodiversity were influenced by disturbances.
Results
Human disturbances, such as coffee management and grazing declined with distance to forest edges, and penetrated at least a kilometer into the forest. Slope was not related to disturbance levels, but several types of disturbances were less common at higher elevations. Among human disturbance types, coffee management reduced liana cover and was associated with altered species composition of trees. The presence of large trees and basal area were not related to any of the disturbance gradients.
Conclusions
Although most anthropogenic disturbances displayed clear edge effects, surprisingly the variation in the chosen forest degradation indices were only weakly related to these disturbances. We suggest that the intersection between edge effects and forest degradation is very context specific and relies much on how particular societies use the forests. For example, in this landscape coffee management seems to be a key driver.
... Moreover, human disturbances often have indirect negative impacts on forest biodiversity (Barlow et al. 2016). For instance, opening up of continuous forests by roads causes fragmentation and increases edge effects, which threatens interior species (Young 1994), facilitates illegal hunting (Benítez-López et al. 2010), and exposes interior forests to wind storms, besides the direct effect of the removal of trees during the road construction (Laurance et al. 2009;Dissanayake et al. 2019). Still, the mere presence of humans in forest landscapes may not necessarily lead to biodiversity loss (Posey 1985), suggesting the importance of understanding the impacts of different types of human disturbances (Alroy 2017;Ahrends et al. 2021). ...
Context Human disturbances can have large impacts on forest structure and biodiversity, and thereby result in forest degradation, a property difficult to detect by remote sensing. Objectives To investigate spatial variation in anthro-pogenic disturbances and their effects on forest structure and biodiversity. Methods In 144 plots of 20 9 20 m distributed across a forest area of 750 km 2 in Southwest Ethiopia, we recorded: landscape variables (e.g., distance to forest edge), different human disturbances, forest structure variables, and species composition of trees and epiphyllous bryophytes. We then first assessed if landscape variables could explain the spatial distribution of disturbances. Second, we analysed how forest structure and biodiversity were influenced by disturbances. Results Human disturbances, such as coffee management and grazing declined with distance to forest edges, and penetrated at least a kilometer into the forest. Slope was not related to disturbance levels, but several types of disturbances were less common at higher elevations. Among human disturbance types, coffee management reduced liana cover and was associated with altered species composition of trees. The presence of large trees and basal area were not related to any of the disturbance gradients. Conclusions Although most anthropogenic disturbances displayed clear edge effects, surprisingly the variation in the chosen forest degradation indices were only weakly related to these disturbances. We suggest that the intersection between edge effects and forest degradation is very context specific and relies much on how particular societies use the forests. For example, in this landscape coffee management seems to be a key driver.
... There are inadequate studies on the effects of hydropower project development on environmentally sensitive areas such as biodiverse areas and protected areas. Hydropower projects have a large number of structures, such as dams, tunnels, canals, powerhouses, internal project roads, access roads, camps, and transmission lines (hydropower project components including associated and auxiliary structures) [22], and most of these structures cause habitat fragmentation, which affects terrestrial faunal species and biodiversity in environmentally sensitive areas [23][24][25][26][27][28]; therefore, studies related to hydropower project distributions in environmentally sensitive areas are necessary. ...
Hydropower project construction is increasing, which can affect the terrestrial environment. Hydropower projects located in environmentally sensitive areas have higher environmental impacts, so I analyzed the spatiotemporal interaction between hydropower project locations and terrestrial environmentally sensitive areas of Nepal to visualize the probable environmental impacts. Most of the existing projects lie on the hill; however, future projects are moving northward. Among the 12 eco-regions of Nepal, hydropower projects are located in 10 eco-regions. Hydropower projects were found to interact with more than half of the biodiverse areas of the country (28 out of 45), and more than five thousand megawatts of hydropower projects are located completely inside these biodiverse areas. The study suggests that the interaction between hydropower projects and environmentally sensitive areas might increase in the future. Hydropower projects should avoid environmentally sensitive areas such as biodiverse areas and protected areas as much as possible to minimize the impacts. Rapid hydropower development is a necessity in countries such as Nepal, so further studies on the effects of hydropower projects on environmentally sensitive areas as well as improvement of the quality of the environmental assessment of the projects are necessary for environmentally friendly development.
... Thus, we included mean elevation for each transect, derived from a 90-m digital elevation model [47]. To account for the effect of roads on species occurrence, we obtained road information from the Nepalese Department of Survey (Kathmandu, Nepal), given the recognized importance of roads in adversely affecting ungulate occurrence across the region [48]. To account for the potential effect of agricultural areas, we manually digitized all agricultural patches identified using high resolution Google Earth imagery (Google Inc., Mountain View, CA, USA) using QGIS 3.12.1 [49]. ...
Understanding how wildlife interacts with human activities across non-protected areas are critical for conservation. This is especially true for ungulates that inhabit human-dominated landscapes outside the protected area system in Nepal, where wildlife often coexists with livestock. Here we investigated how elevation, agricultural land, distance from roads, and the relative abundance of livestock (goats, sheep, cow and buffalo) influenced wild ungulate chital (Axis axis), nilgai (Boselaphustrago camelus), wild boar (Sus scrofa) and sambar (Rusa unicolor) abundance and occurrence. We counted all individuals of wild ungulates and livestock along 35 transects conducted between November 2017 and March 2018 in community forests of Bara and Rautahat distracts in the lowlands of Nepal. We assessed abundance and occurrence relation to covariates using Generalized Linear Models. We found that livestock outnumbered wild ungulates 6.6 to 1. Wild boar was the most abundant wild ungulate, followed by nilgai, chital, and sambar. Elevation and livestock abundance were the most important covariates affecting the overall abundance of wild ungulates and the distribution of each individual ungulate species. Our results suggest spatial segregation between wild ungulates, which occur mainly on high grounds (> 300 m.a.s.l.), and livestock that concentrate across low ground habitats (< 300 m.a.s.l.). Our results provide a critical first step to inform conservation in community forest areas of Nepal, where wildlife interacts with people and their livestock. Finding better strategies to allow the coexistence of ungu-lates with people and their livestock is imperative if they are to persist into the future.
... This finding means that in areas of conservation importance, recreational activities are more desirable among urban and rural residents for the future. As mammals are more sensitive to the presence of humans (Benítez-López et al., 2010;Barbosa et al., 2020), this confrontation can be detrimental to the future of species richness and the ecosystem services that depend on the persistence of these mammal communities (Naiman, 1988;Rosas et al., 2008;Nickell et al., 2018); specifically because ongoing outdoor recreational activities have adverse effects on the abundance and richness of mammals and birds (Bötsch et al., 2017;Larson et al., 2019). Forests are also especially desirable for Recreation; probably because of their esthetic values, which distinguishes this ecosystem from a wider context (e.g., grassland ecosystems and agricultural lands; cf. ...
We provide a picture of public attitudes toward desirable land uses and land features (LULFs) for the future of the Upper Missouri River Basin (UMRB) and examine if residents’ desires are correlated with socioenvironmental conditions of their landscapes. We conducted a survey of residents in 22 human population centers (HPCs), generated a ranking of residents’ desired LULFs, and performed a correlation analysis of the relationship between the scores dedicated to LULFs and 24 variables linked to socioenvironmental conditions of landscapes. Our results indicate that there was strong agreement among residents of the UMRB about the most desirable LULFs despite large socioenvironmental differences across the region. Agriculture was generally found to be among the most desirable LULFs in the UMRB, but it was especially desirable in rural communities. LULFs related to development and energy had more variable responses and were among the least desirable LULFs in the UMRB. Hunting was more desirable in HPCs surrounded by grasslands and public lands. Overall, non-monetary LULFs were more strongly valued when looking into the future. We conclude that the future that residents desire to see on their landscapes is partly influenced by the current status of socioenvironmental conditions of their landscapes. Concurrently, these conditions, can be, to a large extent, the product of residents’ past and current activities on their landscapes. Thus, change in residents’ desires depends on change in these conditions, and probably, vice versa.
... Indeed, road mortality is the most common cause of death for some wildlife species (Bastianelli et al., 2021;Fahrig and Rytwinski, 2009;Rytwinski and Fahrig, 2015), thus increasing the risk of local extinction (Asari et al., 2020;Chen, 2015;Torres et al., 2016). Although almost all terrestrial animals are affected by road mortality, such as insects, reptiles, amphibians, birds and mammals (Benítez-López et al., 2010;Huijser et al., 2009;Seiler and Helldin, 2006), reliable information on the magnitude of road mortality is typically only available for larger-bodied species. Collisions with ungulate species are particularly well-documented, because those create significant economic damages (i. ...
Wildlife-vehicle collisions (WVC) strongly impact road safety. While technical aspects of collision risk and the effects of roads on animal populations are well studied, knowledge about wildlife behaviour prior to and during contact with oncoming vehicles as a crucial aspect of collision risk is still lacking. We analysed 28,400 hours of video data (thermal network cameras at 14 road sections in southwest Germany) with 2,841 animal-vehicle encounters (1,960 roe deer, Capreolus capreolus, 696 red fox, Vulpes vulpes and 185 wild boar, Sus scrofa) and classified animal behaviour before and during contact with a vehicle. We fitted two sets of models to the data. In the first step, we modelled the intensity of the behavioural reaction exhibited by the animals as a function of behavioural and environmental predictors using ordinal Bayesian mixed-effect regression models. In a second step, we modelled the probability of a positive vs. a negative behavioural response in terms of WVC risk using binomial mixed-effect regression models. Both the intensity of behavioural reactions as well as the degree of risk during the interaction with oncoming vehicles differed among the species and as a function of road section layout. Our results showed that animal attentiveness, the behaviour a priori, access to cover, vehicle type and biological seasonality were important predictors of an animal's response to oncoming vehicles. More specifically, roe deer reacted to oncoming vehicles mostly with short movements away from the road, foxes often reacted unpredictably and wild boar behaviour appeared to be least affected by oncoming vehicles. Thus, we suggest that collision risk for common European mammals is shaped by the interplay of vehicle type, the road layout as well as the species-specific behavioural repertoire including the attentiveness of the animal and the behavioural state prior to an approaching vehicle. In addition, wildlife warning reflectors, a frequently used technique in WVC mitigation, did not alter behavioural reactions and thus failed to reduce WVC risk.
... obs., AN). New roads and off-road trails could cause further fragmentation of the habitat, reduce connectivity between populations, increases human accessibility and block the natural flow of flood water (Gibbs & Shriver, 2002;Benítez-López et al., 2010;Brehme et al., 2013). ...
... obs., AN). New roads and off-road trails could cause further fragmentation of the habitat, reduce connectivity between populations, increases human accessibility and block the natural flow of flood water (Gibbs & Shriver, 2002;Benítez-López et al., 2010;Brehme et al., 2013). ...
The rapidity of the global biome changes caused by humans exceeds the slow resilience of ecosystems, especially fragile biomes such as deserts. Habitat destruction is the main threat to biodiversity loss, it is seventy times more threatening than climate change. Quantifying and mapping habitat destruction is essential for biodiversity conservation plans, as it quantifies the remaining habitats and prioritizes the most important and threatened habitats. Using remote sensing and GIS, The Egyptian Dabb lizard Uromastyx aegyptia distribution in the eastern desert of Egypt was modeled and its destroyed suitable habitats were mapped and quantified. Precipitation seasonality was the most important variable contributing to the species' habitat suitability as well as NDVI. Two regions were identified as suitable, nearly half (44%) of the northern suitable region is destroyed, and the rest is low-quality habitat. In the southern region, there is an expansion in energy projects that lies in the most important areas for Dabb lizard conservation. A great conservation opportunity could be seized if energy projects considered activating and implementing their biodiversity conservation plans.
... Along with induced topographical complexity, road corridors on grassland introduce prominent and diverse vegetation elements attracting a variety of bird species, leading to local increment in species richness and abundance, especially along the quieter and narrower roads (Forman et al. 2002). It has been also suggested that birds tend to avoid infrastructures more consistently in open habitat than in forests (Benítez-López et al. 2010). ...
We examined interacting effects of habitat structure, topographic landscape, road edge and vehicle traffic (density and noise), on bird species composition, abundance and diversity in the laurel forest of Tenerife (Canaries). We examined multivariate habitat and landscape factors determining bird community composition and structure, and modality of specific responses by comparing road edge vs interior zones. Abundance of breeding birds in laurel forest showed slight to no increases in response to roads. Two specialized taxa, the palaeoendemic pigeon Columba bollii and Regulus regulus, revealed neatest negative reductions in abundance near roads. Higher noise levels, vegetation density, lower canopy closure and wood selective extraction characterized roadsides. Most passerines showed moderate affinity for forest edges and did not evidence decreases due to road proximity. The topographic landscape in these mountainous areas strongly interacted with road edge effects to determine bird community structure. Narrow road disturbances on the laurel forest was related to moderate increase in bird abundance and diversity near edges, but at the cost of losing presence of forest-demanding species playing important ecological roles.
... Funding from multilateral development banks, bilateral cooperation agencies, and the private sector could prioritize investing in infrastructure to support sustainable tourism in places where biodiversity is high (50) and to advance the international policy agendas of mainstreaming biodiversity in the tourism and infrastructure sectors (51,52). Nonetheless, it is critical to recognize that increased access to protected areas by expanding road networks in undisturbed areas (e.g., Amistad International Park), might cause biodiversity declines, as has been demonstrated in other tropical regions (53,54). Therefore, a crucial management challenge for Costa Rica, and other countries depending on tourism, is to plan infrastructure development in the least destructive ways. ...
Significance
Tourism accounts for roughly 10% of global gross domestic product, with nature-based tourism its fastest-growing sector in the past 10 years. Nature-based tourism can theoretically contribute to local and sustainable development by creating attractive livelihoods that support biodiversity conservation, but whether tourists prefer to visit more biodiverse destinations is poorly understood. We examine this question in Costa Rica and find that more biodiverse places tend indeed to attract more tourists, especially where there is infrastructure that makes these places more accessible. Safeguarding terrestrial biodiversity is critical to preserving the substantial economic benefits that countries derive from tourism. Investments in both biodiversity conservation and infrastructure are needed to allow biodiverse countries to rely on tourism for their sustainable development.
... However, these relationships are not linear, and cockatoo survival may be influenced by processes that are sometimes recognized as environmental Kuznet's curves (McPherson & Nieswiadomy, 2005;Mills & Waite, 2009): rising GDP brings motorized transport links and mobile phone connections which initially increase trapping, trading effort and efficiency (Stearman, 2000;Pires, 2012), but with their further wealth local people rely less on illegal activities or forest use to survive or boost their incomes (Lunstrum & Giv a, 2020), and cockatoo survival then increases. Direct and indirect negative effects of roads on mammal and bird population densities are well documented for many species globally (Ben ıtez-L opez, Alkemade & Verweij, 2010;Kociolek et al., 2011); in the case of the cockatoos, the effect is most likely a consequence of the access that roads give for trapping and trade (Harris et al., 2017). ...
A challenge with species that have disappeared from most of their range is to identify the correlates of local persistence. With species decimated by trade, site‐specific trapping risk is hard to capture by remotely accessed predictors. The recently split yellow‐crested cockatoo Cacatua sulphurea and citron‐crested cockatoo C. citrinocristata have undergone catastrophic declines due to habitat loss and especially trapping, and are now extinct in much of their former range across Indonesia. Of 144 sites on 30 islands known to contain the species in 1950, only 76 on 27 islands did so in 2017–2019, with many of the other 68 experiencing extinctions between 1985 and 2000. We compared socio‐ecological conditions such as forest cover and loss, human population density and infrastructure, and protected area status between the occupied and unoccupied sites, using ‘random forests’ within decreasing time intervals 1950–2015. Populations on Sulawesi and West Nusa Tenggara were more likely to become extinct than those on Sumba, Timor‐Leste and small remote islands. Sites retaining cockatoos had high proportions of tree cover, low road density and low human densities. The relative importance of these factors changed little over time, but road density and human density became respectively more and less important in recent years. The examination of local conditions at ‘false negative’ sites (where cockatoos survived contrary to model predictions) showed that, particularly in recent years, cockatoo survival has been promoted by site‐specific protection due to traditional beliefs, NGO activities, dedicated individual residents and local topographic barriers. Some of these local influences add complexity to the task of conserving cockatoo strongholds, but also offer exciting possibilities for low‐cost conservation prescriptions tailored to individual sites. Studies combining field and remotely sensed data, and examining false negative sites for beneficial location‐specific conditions, have broad application for the conservation of taxa with once‐large ranges. A challenge with endangered species that have disappeared from most of their range is to identify the conditions that allow survival at just a few sites. We located remnant populations of the CR yellow‐crested cockatoo and CR citron‐crested cockatoo and used remotely sensed socio‐ecological variables to explain why they avoided local extinction. Tree cover and sparse human densities promoted cockatoo survival but site‐specific conditions (e.g. sacred groves, NGO activities) were also important. These local influences offer exciting possibilities for conservation prescriptions tailored to individual sites.
... Dust falling on plants, for example, smothers the leaves and blocks stomata [22]. Furthermore, roads have numerous ecological consequences, not just on vegetation but also on animal habitats, slowing animal movement, isolating populations and communities, and causing mortality [23,24]. ...
Thirty years ago, Mongolia’s Gobi Desert was intact, roadless and had low traffic, and it was a refuge for many endangered and rare species. A large mining boom and significant livestock grazing are currently putting pressure on the desert. Mining products were transported by trucks on dirt (gravel) roads between 2000 and 2012. Emphasizing its importance in the Mongolian economy, a paved road was constructed in 2012 along the dirt road. Unfortunately, vegetation along the paved road was removed without restoration. In the desert, locals continue to use, create and extend dirt roads. The impact of these roads on the vegetation has yet to be studied. We estimated the spatial extent of the dirt-road corridors in three time intervals (the years 2010, 2015 and 2020) and evaluated the vegetation along both paved and dirt roads at three distances (100, 500, and 900 m) from the road. Within ten years, the length of paved roads and soil dirt roads nearly doubled, although the majority of them were developed and created between 2015 and 2020. A single track makes up around 42 percent of the soil road, whereas the remaining 58 percent are roads consisting of three to four tracks with an average width of 26.5 m. The vegetation along the paved road was lower in terms of species richness, canopy cover, and the basal gap between perennial plants and biomass, compared to the soil road. Although the effects of soil roads on the vegetation along the roads is less negative than the effects of the paved road, the corridors formed along the soil roads span a non-negligible area of pastureland in the region. The vegetation along the already-constructed paved road in the desert should be artificially reclaimed with the aim of expediting natural revegetation. Moreover, a “new legislation” is required to prevent continued degradation due to the ongoing creation and extension of soil road corridors by local populations in the desert.
... Higher genetic diversity was observed in lowland tapir living in the Amazon forest (Pinho et al., 2014), suggesting a slight genetic variation reduction in the lowland tapir populations inhabiting Serra do Mar Biodiversity Corridor. Although this corridor comprises many protected areas, hunting and roads are widespread in this area, causing large mammal density reduction (Benítez-López et al., 2010;Galetti et al., 2017). The genetic diversity and the effective population size were higher in the coastal than in the inland population, indicating that the coastal population has more individuals genetically contributing for the Ne, probably because Serra do Mar (coastal region) harbors the largest tapir population in the Atlantic forest biome (Medici et al., 2012). ...
Forest corridor has been considered the main strategy for maintaining gene flow between isolated populations, yet their effectivity is poorly tested. Assessing signatures of genetic variation loss, gene flow reduction and inbreeding may be helpful for conservation of the biodiversity that needs large continuous areas. Here we evaluated the genetic structure and diversity of the largest neotropical mammal, the lowland tapir (Tapirus terrestris), living in the largest Atlantic forest corridor in Brazil. We used fecal-derived DNA, genotyped nine polymorphic microsatellite loci of 75 tapirs, and quantified genetic differentiation, genetic diversity, and landscape resistance to gene flow. We found genetic differentiation between the inland and coastal populations, which may be explained by elevation. Expected heterozygosity ranged between 0.64 (inland population) and 0.78 (coastal population), and a small Ne was observed in both populations. We demonstrated that even large continuous rainforests are not totally permeable to the gene flow of large organisms. Our study also changes our perception about the pristine of continuous corridors and their role for long-term survival of large mammals, suggesting that tapir conservation efforts should be taken even for populations in the large protected areas.
Full text available: https://www.sciencedirect.com/science/article/pii/S2530064422000128
... Land use changes originating from anthropic activities significantly disturb ecosystem dynamics worldwide. They therefore represent one of the main threats to biodiversity and associated ecosystem services (Benítez-López et al., 2010;McKinney, 2006). These land use changes deeply perturb the structure of the landscape and the associated habitats, thus modifying both the landscape composition (i.e., land cover) and configuration (i.e., spatial arrangement of land cover) (Fahrig et al., 2011;Taylor et al., 1993). ...
Urban landscapes are rapid changing ecosystems with diverse urban forms that impede the movement of organisms. Therefore, designing and modelling ecological networks to identify biodiversity reservoirs and their corridors are crucial aspects of land management in terms of population persistence and survival. However, the land cover/use maps used for landscape connectivity modelling can lack information in such a highly complex environment. In this context, remote sensing approaches are gaining interest for the development of accurate land cover/use maps. We tested the efficiency of an object-based classification using open-source projects and free images to identify vegetation strata at a very fine scale and evaluated its contribution to landscape connectivity modelling. We compared different spatial and thematic resolutions from existing databases and object-based image analyses in three French cities. Our results suggested that this remote sensing approach produced reliable land cover maps to differentiate artificial areas, tree vegetation and herbaceous vegetation. Land cover maps enhanced with the remote sensing products substantially changed the structural connectivity indices, showing an improvement up to four times the proportion of herbaceous and tree vegetation. In addition, functional connectivity indices evaluated for several forest species were mainly impacted for medium dispersers in quantitative (metrics) and qualitative (corridors) estimations. Thus, the combination of this reproductible remote sensing approach and landscape connectivity modelling at a very fine scale provides new insights into the characterisation of ecological networks for conservation planning.
... Direct effects involve wildlife mortality caused by vehicle collisions, which have been identified as a major threat. Roadkills affect healthy individuals in a non-selective manner (Bujoczek et al. 2011), and then cause population declines and even extirpations (Fahrig and Rytwinski 2009;Benítez-López et al. 2010;Kociolek et al. 2010;Jack et al. 2015). ...
The main factors affecting specific road casualty rates are related to life-history traits, road features, and landscape variables. After road inauguration, roadkill rate and spatial and temporal patterns can change substantially due to changes in traffic intensity, avoidance behaviour or local population decline. Despite the Canary Islands constituting a biodiversity hotspot, Canarian ecosystems are highly threatened because of the high human density, and studies on anthropogenic sources of mortality of wildlife are scarce. Here, we counted roadkills during two annual cycles after the inauguration of an 8.8-km-road section on Tenerife, the largest and most densely populated island of the Canaries. We counted 694 roadkills belonging to a minimum of 19 species of birds and six species of introduced mammals. Seasonal variation was apparent during both annual cycles, particularly for birds, being the majority of victims concentrated in May and June. Although traffic intensity increased since road inauguration, the number of roadkills decreased significantly in the second annual cycle. The reduction in road mortality in the second cycle could be related to some non-mutually exclusive factors such as population decline, road avoidance, or weather conditions. As road networks of the Canary Islands are still increasing, further studies quantifying road mortality impacts on Canarian ecosystems and threatened species are urgently needed to guarantee the management and conservation of its fragile wildlife.
... Thus, the differences in soundscape indexes suggest we can quickly provide evidence, using ARUs, of biological change as a function of a winter environment altered physically and acoustically by a high-traffic interstate. Likewise, the observed, linear decline in biophony (regardless of filter) as a function of technophony may suggest that traffic intensity is as important to consider as the presence of roads unlike past reviews suggest (Benítez-López et al. 2010). More broadly, the extent of the interstate highway system and similar roadway structures globally (Laurance et al. 2014), plus the depth of the road ecology literature, speaks to the magnitude of this acoustic and likely biological change in agroecosystems and other heavily managed ecosystems. ...
ContextMost data collection and analyses in soundscape ecology have focused on summer or breeding seasons in urban or protected landscapes, missing important acoustic dynamics in winter, non-breeding periods and in agricultural landscapes, a land-use that constitutes 39% of ice-free surface globally.Objectives
To address these gaps, we examined the variation of winter soundscapes across a rural agricultural landscape of Nebraska, USA. We compared high and low traffic sites, testing if traffic levels affected soundscape structure.Methods
We recorded sound over two winters at 19 sites located adjacent to major and minor roadways. We calculated eight unique soundscape indexes to quantify the soundscape over time as a function of traffic and land cover. We applied filters at 80, 1000, and 2000 Hz.ResultsWe found clear statistical differences between high and low traffic sites in 7 of 8 soundscape indexes. Soundscape varied throughout the day, but not throughout the season. There was a clear negative correlation between technophony (human-derived sounds) and biophony (ecologically derived sounds) across sites. We found that not all indices may be suitable for all ecosystems.Conclusions
We quantified the effects of noise pollution on the soundscape of understudied habitats during winter months. By using soundscape indexes as surrogates for biodiversity, acoustic sampling could be an effective method for monitoring biodiversity when traditional methods may be ineffective or too costly. However, caution needs to be taken when choosing indices.
... Assessing WUI impacts on wildlife abundance and diversity, for example, may require the selection of a neighborhood size that represents the distance over which ecological impacts can be detected. The magnitude of the effect at any given distance may vary substantially over ranges up to several kilometers and may also depend heavily on the species of interest (Benítez-López et al., 2010). Our composite WUI maps ( Figure 5) therefore can be particularly useful for assessing patterns at multiple scales. ...
The wildland‐urban interface (WUI) is the focus of many important land management issues, such as wildfire, habitat fragmentation, invasive species, and human‐wildlife conflicts. Wildfire is an especially critical issue, because housing growth in the WUI increases wildfire ignitions and the number of homes at risk. Identifying the WUI is important for assessing and mitigating impacts of development on wildlands and for protecting homes from natural hazards, but data on housing development for large areas are often coarse. We created new WUI maps for the conterminous U.S. based on 125 million individual building locations, offering higher spatial precision compared to existing maps based on U.S. census housing data. Building point locations were based on a building footprint dataset from Microsoft®. We classified WUI across the conterminous U.S. at 30‐m resolution using a circular neighborhood mapping algorithm with a variable radius to determine thresholds of housing density and vegetation cover. We used our maps to (1) determine the total area of the WUI and number of buildings included, (2) assess the sensitivity of WUI area included and spatial pattern of WUI maps to choice of neighborhood size, (3) assess regional differences between building‐based WUI maps and census‐based WUI maps, and (4) determine how building location accuracy affected WUI map accuracy. Our building‐based WUI maps identified 5.6% – 18.8% of the conterminous U.S. as being in the WUI, with larger neighborhoods increasing WUI area but excluding isolated building clusters. Building‐based maps identified more WUI area relative to census‐based maps for all but the smallest neighborhoods, particularly in the north‐central states, and large differences were attributable to high numbers of non‐housing structures in rural areas. Overall WUI classification accuracy was 98.0%. For wildfire risk mapping and for general purposes, WUI maps based on the 500‐m neighborhood represent the original Federal Register definition of the WUI; these maps include clusters of buildings in and adjacent to wildlands and exclude remote, isolated buildings. Our approach for mapping the WUI offers flexibility and high spatial detail, and can be widely applied to take advantage of the growing availability of high‐resolution building footprint datasets and classification methods.
... Roads also act as barriers to movement for many species, thereby decreasing their access to mates, water, food or other resources (Trombulak and Frissell 2000;Brown et al. 2006), with both genetic and demographic costs to populations, increasing local extinction risk (Shepard et al. 2008). For instance, it has been shown that road proximity can have negative impacts on mammal species abundance or activity (Kozel and Fleharty 1979;Garland and Bradley 1984;Clark et al. 2001), this effect decreasing with the distance to the road (Benítez-López et al. 2010;Medinas et al. 2019). Roads have been also shown to decrease edge permeability for some small mammal species such as the montane akodont Akodon montensis (Ascensão et al. 2017). ...
Roads are among the most widespread signs of man’s presence around the globe. From simple low traffic trails to wide and highly used highways, roads have a wide array of effects on wildlife. In the present study, we tested how habitat reduction by roads may affect the space use and movement patterns of the Cabrera vole ( Microtus cabrerae ), a near-threatened Iberian endemism, often living on road verges. A total of 16 voles were successfully radio-tracked in two habitat patches with different size and proximity to roads. Results showed that individuals from the smaller patch (Verge patch) had smaller and less complex home-ranges than those from the larger patch (Meadow patch). Movement patterns were significantly influenced by the day period but only in individuals from the Verge patch. There was evidence of a barrier effect in both habitat patches, being this effect much more noticeable in the verge population. Overall, this study shows that space use and movement patterns of Cabrera voles near roads may be affected by the degree of habitat reduction imposed by these infrastructures. This suggests that species space use and movement patterns at fine-scale should be accounted for in road planning, even for species that may benefit from road verge habitats as refuges.
As climate change continues to become a serious threat to social and ecological systems, strategies to reduce emissions are becoming increasingly important. Additionally, rising visitation and the prevalent use of private vehicles in parks and protected areas has led to problems related to traffic congestion and parking. The U.S. National Park Service (NPS), for example, has attempted to address such problems as well as reduce emissions by implementing alternative transportation systems (ATS) at select NPS units across the country. Despite their promise of alleviating congestion and capacity issues while also reducing emissions, the implementation of ATS can affect visitor experiences and resource conditions at recreation settings, and place additional demands on NPS budgets. Managers are consequently placed in the precarious position of having to consider trade-offs between environmental, social, and economic interests. In our integrative review we systematically examine the academic as well as grey literature on primary effects and secondary consequences of ATS in NPS units. We synthesize a wide range of literature and provide a holistic understanding of effects, secondary consequences, and emerging trade-offs resulting from the implementation or expansion of ATS in NPS units. We identify a wide variety of positive, negative, and neutral effects on environmental, social, and economic characteristics, such as emissions, the visitor experience, and local employment. We find trade-offs occur at different levels, including between dimensions, between individual characteristics, within characteristics, and across spatial and temporal scales. Our review provides managers with a comprehensive understanding of the effects and trade-offs of ATS, their interactions with management objectives, and their relationships to visitor acceptance. The review also reinforces previous assertions that ATS can be used as a viable management tool to achieve and maintain desired conditions, adds suggestions on how to do so, and highlights opportunities to realize the benefits of ATS.
Disturbance may impact individual birds and ultimately bird populations. If animals avoid disturbed sites this may prevent them from being disturbed directly but may also negatively impact their movement patterns and energy budgets. Avoidance is, however, challenging to study, as it requires following individuals over large spatial scales in order to compare their movement rates between sites in relation to spatiotemporal variation in disturbance intensity. We studied how 48 GPS tracked non‐breeding Eurasian Oystercatchers Haematopus ostralegus utilised two neighbouring roost sites in the Wadden Sea. One roost site is highly influenced by seasonal recreational disturbance whereas the other is an undisturbed sandbar. We analysed roost choice and the probability of moving away from the disturbed roost site with regard to a seasonal recreation activity index, weekends and night‐time. Oystercatchers often chose to roost on the undisturbed site, even if they were foraging closer to the disturbed roost. The probability that Oystercatchers chose to roost on the disturbed site was negatively correlated with the recreation activity index and lowest in the tourist season (summer and early autumn), indicating that birds used the site less often when recreation levels were high. Furthermore, the probability that birds moved away from the disturbed site during high tide was positively correlated with the recreation activity index. The choice to roost on the undisturbed site implies that birds must fly an additional 8 km during one high tide period, which equates to 3.4% of daily energy expenditure of an average oystercatcher. Our study tentatively suggests that the costs of avoidance may outweigh the energetic cost of direct flight responses and thus that avoidance of disturbed sites requires more attention in future disturbance impact studies. Nature managers should evaluate whether high‐quality undisturbed roosting sites are available near foraging sites, and in our case closing of a section of the disturbed site during high tides in the tourist season may mitigate much disturbance impact.
Setting a quantitative conservation target comprises an important step in systematic conservation planning. This paper outlines a first attempt to calculate quantitative conservation targets for selection of national parks, wildlife refuges, and protected areas in 21 terrestrial ecosystems at the national level. To formulate and calculate targets, we further developed Pressey and Taffs’s formula (2001) and included baseline target, natural rarity and potential ecological vulnerability (PEV) in our formulation. The PEV was defined as the potential impacts resulting from exposure to main threats plus ecological sensitivity of any land tract without considering adaptation. Our results showed that the minimum and maximum conservation targets for selection of national parks, wildlife refuges and protected areas as percentages of the area of each terrestrial ecosystem were between 1.44% - 3.17%, 3.87% - 8.08%, and 6.36% - 13.27%, respectively. We showed how to design an effective network of three management categories including the full range of terrestrial ecosystem types within the country. Nationally and under current conditions, we found that the Moderate-Desert Woodland & Shrublands and the Cold-Desert Steppe Scrubland ecosystems required the most and least attention, respectively. This finding provided additional support for the establishment of a representative, comprehensive and balanced network of protected areas in the country and finally a fundamental guide for effective ecological conservation and environmental management.
Road and highway development can provide multiple benefits to society, but without careful planning, this development can result in negative social and environmental impacts. The 1,200 km Pan Borneo Highway project (PBH) in Sabah, Malaysian Borneo, is constructing new highways and up-grading 2-lane roads to 4-lane highways. We assessed the potential impact of the PBH on communities using three width scenarios of 50m, 75m and 100m for planned highway alignments, and identified potentially impacted dwellings and community lands. We estimated that 65-93 villages will be impacted, and that 1,712-7,093 dwellings and 3,420-6,695 ha of community lands (e.g. paddy, oil palm smallholdings and rubber) may be lost to the PBH. Due to land tenure technicalities, many affected households may not get compensation for the loss of their homes and lands. The PBH will disproportionally impact Sabah's Indigenous Peoples, with the Kadazandusun most affected. For this study to be constructive, we provide a low impact alternative alignment for a part of the PBH; discuss the socio-economic and cultural impacts of the PBH, and offer some perspectives on current planning procedures in Sabah to support more sustainable and equitable development.
Linear Transport Infrastructure (LTI) often has important impacts on wildlife and landscape processes. Two reviews provided early insight and nuance into LTI impacts on birdlife but were published when road ecology experiments were still being developed. Four factors were identified to impact birds near roads: habitat quality, species-specific traits, traffic noise, and infrastructure. Although early work identified traffic noise as the main selective force, recent studies lend more support to habitat quality and infrastructure. However, this literature was deemed to possess low inferential strength given inconsistent data collection, inadequate management of confounding variables, limited inclusion of vehicle-free environments, short-term experimental timeframes, and use of methodologies susceptible to bias. A new experimental framework for better evaluation of the impact of roads on birdlife is proposed. This would facilitate the construction of species and/or community profiles useful in the design, construction, and management of transport networks.
Forest fragmentation has resulted in a breakdown in connectivity for arboreal species. Effects of fragmentation are particularly acute in forest patches in densely populated countries, resulting in high mortality in many species attempting to cross roads to travel between forest patches. We evaluated the use of three, single-line artificial canopy bridges made of polypropylene ropes in a forest patch in northeastern Bangladesh. Camera traps were used to determine the extent of bridge use by different species. A total of 1060 events of bridge use by mammals were observed using our artificial canopy bridges over the 157 camera trap days. Eight mammal species, including five primate species, two squirrel species and one palm civet species were recorded using the bridges at varying levels of frequency. The location of the bridge and season influenced bridge use. We did not observe mortality of mammals from road accidents or electrocution during the study period. We suggest that artificial canopy bridges increased connectivity between forest patches and reduced mortality from road accidents and electrocution. We strongly recommend the use of this and other, simple canopy bridges to prevent mortality of arboreal mammals.
Acoustic communication is a way of information exchange between individuals, and it is used by several animal species. Therefore, the detection, recognition and correct understanding of acoustic signals are key factors in effective communication. The priority of acoustic communication is effectiveness rather than perfection, being effective avoids affecting the sound-based communication system of the species. One of the factors that can affect effective communication is the overlap in time and frequency during signal transmission, known as signal masking. One type of sound that can cause masking is anthropogenic noise, which is currently increasing due to urban growth and consequently motorized transportation and machinery. When exposed to anthropogenic noise, animals can use compensatory mechanisms to deal with sound masking, such as the modification of acoustic parameters of their acoustic signal. Here, we performed a meta-analysis investigating whether different taxa have a general tendency for changes in acoustic parameters due to anthropogenic noise, we used taxa and acoustic parameters available in the literature that met the minimum criteria to perform a meta-analysis. We hypothesized that animals exposed to anthropogenic noise use compensation mechanisms, such as changes in dominant, maximum or minimum frequencies, call duration, note duration and call rate to deal with masking. We performed a meta-analysis, which synthesized information from 73 studies comprising 82 species of three taxa: insects, anurans and birds. Our results showed that in the presence of anthropogenic noise, insects did not change the acoustic parameters, while anurans increased call amplitude and birds increased dominant frequency, minimum and maximum frequencies, note duration and amplitude of their songs. The different responses of the groups to anthropogenic noise may be related to their particularities in the production and reception of sound or to the differences in the acoustic parameters considered between the taxa and also the lack of studies in some taxa.
Ecological effects on roads construction include physical disturbance, habitats loss, extinction of populations of species near road edges, mortality of wildlife that are using roads edges as habitat, and the scattering of wildlife (including invasive species and alien species) along road network. In other words, roads construction contributes essentially to the socio-economic and cultural development of rural communities. Improved road infrastructure facilitates rural population to find work in and beyond their respective communities. Similarly, the city of Bo has been experiencing 21st Century massive asphalt roads construction. This research is to assess the effects of road construction on ecological biodiversity on the livelihood of the people in Bo City. Biodiversity is increasingly threatened by rapid infrastructure expansion and its associated ecological effects. Infrastructure such as roads, alter ecological conditions by cutting through habitats and consequently reducing populations of many wildlife species. As a result local species in abundance decline in the nearness of infrastructure and increase with distance from the infrastructure until leveling off at a certain threshold distance. This decrease in population density varies by taxonomic group, with mammals being affected over long distance than birds (Benitez, Lopez, et al 2010.
Roadkill is one of the most striking ecological impact of the roads, that can have direct consequences on animal populations and sometimes pose danger to people. The paper gives the results of a 4-year monitoring campaign of vertebrate roadkill along a two-lane municipal road in the Eastern Po Valley. The road connects the city of Ferrara (Italy) with the border of the Natura 2000 site IT4060016, crossing arable lands, orchards, and residential villages. Mean mortality has been of 10.5 ind./km/year, like previous results from a similar road in the same landscape. Mammal mortality, with 4.1 ind./km/year, has resulted 27 times higher than on similar roads in the Western Po Valley. The most affected taxa have been the hedgehog Erinaceus europaeus, toads (Bufotes balearicus and Bufo bufo), sparrows (Passer italiae and Passer sp.), Columbidae, Athene noctua
and unidentified birds. Traffic volume was inversely correlated with mortality: traffic decreased from the city towards the Natura 2000 site while mortality increased. The vertebrate community close to the protected area was clearly distinct. Mortality has not changed among years but has changed among seasons, peaking in July both for number of killed animals and for number of involved taxa but also showing other peaks in early spring and autumn. Some particularly dangerous road stretches have been identified, where solutions for roadkill mitigation may be adopted. Climate warming can change the timing of reproductive migration, changing the exposure risk to roadkill. Key words: Roadkill, Eastern Po Valley, Erinaceus europaeus, amphibians, Passer italiae.
Background: There are great disparities in the quantity and quality of infrastructure.
European countries such as Denmark, Germany, Switzerland, and the UK have close
to 200 km of road per 100 km2, and the Netherlands over 300 km per 100 km2. By
contrast, Kenya and Indonesia have <30, Laos and Morocco <20, Tanzania and
Bolivia <10, and Mauritania only 1 km per 100 km2. As these figures show, there is a
significant backlog of transport infrastructure investment in both rural and urban
areas, especially in sub‐Saharan Africa. This situation is often exacerbated by weak
governance and an inadequate regulatory framework with poor enforcement which
lead to high costs and defective construction.
The wellbeing of many poor people is constrained by lack of transport, which is
called “transport poverty”. Lucas et al. suggest that up to 90% of the world's population
are transport poor when defined as meeting at least one of the following
criteria: (1) lack of available suitable transport, (2) lack of transport to necessary
destinations, (3) cost of necessary transport puts household below the income
poverty line, (4) excessive travel time, or (5) unsafe or unhealthy travel conditions.
Objectives: The aim of this evidence and gap map (EGM) is to identify, map, and
describe existing evidence from studies reporting the quantitative effects of transport
sector interventions related to all means of transport (roads, rail, trams and
monorail, ports, shipping, and inland waterways, and air transport).
Methods: The intervention framework of this EGM reframes Berg et al's three categories
(infrastructure, prices, and regulations) broadly as infrastructure, incentives,
and institutions as subcategories for each intervention category which are each
mode of transport (road, rail trams and monorail, ports, shipping, and inlands waterways,
and air transport). This EGM identifies the area where intervention studies
have been conducted as well as the current gaps in the evidence base.This EGM includes ongoing and completed impact evaluations and systematic reviews
(SRs) of the effectiveness of transport sector interventions. This is a map of
effectiveness studies (impact evaluations). The impact evaluations include experimental
designs, nonexperimental designs, and regression designs. We have not included
the before versus after studies and qualitative studies in this map. The search
strategies included both academic and grey literature search on organisational
websites, bibliographic searches and hand search of journals.
An EGM is a table or matrix which provides a visual presentation of the evidence in a
particular sector or a subsector. The map is presented as a matrix in which rows are
intervention categories (e.g., roads) and subcategories (e.g., infrastructure) and the
column outcome domains (e.g., environment) and subcategories as (e.g., air quality).
Each cell contains studies of the corresponding intervention for the relevant outcome,
with links to the available studies. Included studies were coded according to
the intervention and outcomes assessed and additional filters as region, population,
and study design. Critical appraisal of included SR was done using A Measurement
Tool to Assess Systematic Reviews (AMSTAR ‐2) rating scale.
Selection Criteria: The search included both academic and grey literature available
online. We included impact evaluations and SRs that assessed the effectiveness of
transport sector interventions in low‐ and middle‐income countries.
Results: This EGM on the transport sector includes 466 studies from low‐ and middleincome
countries, of which 34 are SRs and 432 impact evaluations. There are many
studies of the effects of roads intervention in all three subcategories—infrastructure,
incentives, and institutions, with the most studies in the infrastructure subcategories.
There are no or fewer studies on the interventions category ports, shipping, and waterways
and for civil aviation (Air Transport).
In the outcomes, the evidence is most concentrated on transport infrastructure,
services, and use, with the greatest concentration of evidence on transport time and
cost (193 studies) and transport modality (160 studies). There is also a concentration
of evidence on economic development and health and education outcomes. There
are 139 studies on economic development, 90 studies on household income and
poverty, and 101 studies on health outcomes.
The major gaps in evidence are from all sectors except roads in the intervention. And
there is a lack of evidence on outcome categories such as cultural heritage and
cultural diversity and very little evidence on displacement (three studies), noise
pollution (four studies), and transport equity (2). There is a moderate amount of
evidence on infrastructure quantity (32 studies), location, land use and prices (49
studies), market access (29 studies), access to education facilities (23 studies), air
quality (50 studies), and cost analysis including ex post CBA (21 studies).
The evidence is mostly fromEast Asia and the Pacific Region (223 studies (40%), then the
evidence is from the sub‐Saharan Africa (108 studies), South Asia (96 studies), Latin
America & Caribbean (79 studies). The least evidence is from Middle East & North Africa
(30 studies) and Europe & Central Asia (20 studies). The most used study design is other
regression design in all regions, with largest number from East Asia and Pacific (274).
There is total 33 completed SRs identified and one ongoing, around 85% of the SR are
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rated low confidence, and 12% rated as medium confidence. Only one review was rated
as high confidence. This EGM contains the available evidence in English.
Conclusion: This map shows the available evidence and gaps on the effectiveness of
transport sector intervention in low‐ and middle‐income countries. The evidence is highly
concentrated on the outcome of transport infrastructure (especially roads), service, and
use (351 studies). It is also concentrated in a specific region—East Asia and Pacific (223
studies)—and more urban populations (261 studies). Sectors with great development
potential, such as waterways, are under‐examined reflecting also under‐investment.
The available evidence can guide the policymakers, and government‐related to
transport sector intervention and its effects on many outcomes across sectors.
There is a need to conduct experimental studies and quality SRs in this area. Environment,
gender equity, culture, and education in low‐ and middle‐income countries
are under‐researched areas in the transport sector.
The already high risk of wildlife-vehicle collisions (WVC) is growing due to higher traffic and road densities and regionally also due to growing population densities of some ungulate species. As a result, the threats to human health and property as well as wildlife mortality of common and of rare species blow up. In this respect, the research project focused on two subjects. On the one hand a method for identifying WVC-hotspots was developed (I.) and on the other hand a synopsis and evaluation of applied fencing systems was carried out and recommendations for improvement were derived (II). I. For the identification of WVC-hotspots, more than 800.000 WVC data could be analyzed via GIS. The data result from contributions of various administrations of the federal states of Germany and the German Animal Location Register (TFK / Tierfund-Kataster) and comprise WVC from 2016-2017 in Bavaria and from 2012 to 2017 in many of the other states; but for some areas, the data were insufficient. Overall, 30.393 road sections could be identified which fulfill the criteria of at least six WVC within a maximum distance of 200 m between the respective accidents. Those sections comprise 56.6% of all registered WVC but only 4% of the road network (29.580 km of 783.145 km). 11.912 of the sections are characterized by more than 15 accidents per km and were defined as WVC-hotspot sections (WUSS). Therefore, for the moment and for the majority of the German states the most important WVC-sections along the road network are identified and can be prioritized for mitigation measures. For the remaining area (and future improvement of identifying hotspots), the WVC registration system must be adjusted and hotspots with a high continuity over a long period are left to be recognized. Therefore, a nationwide consistent registration system must still be developed as well as automated routines for weighted identification of hotspots (reporting and evaluation system). Furthermore the landscape and road area characteristics that distinguish the meanwhile identified WVC-hotspot sections from other road section should be identified to find how landscaping can reduce personal injuries, damage to property and animal mortality and suffering. II. In Germany, fencing of roads is regulated by the wildlife fence regulations (WSchuZR), which was revised in 1985 for the last time. This regulation however is not up to date anymore, and does not account for actual requirements, new scientific results as well as changed environmental conditions. This is displayed in several aspects as increased wildlife population densities in Germany, which have surpassed density specifications, mentioned in the wildlife fence regulations several fold, an insufficient maintenance of wildlife fences by German road maintenance service and species conservation, which is still not noted in wildlife fence regulations. By interviewing road maintenance managers in ten districts we reveal that
Chronic traffic noise is increasingly recognised as a potential hazard to wildlife. Various songbird species, for example, have been shown to breed poorly in traffic noise exposed habitats. However, identifying whether noise is causal in this requires experimental approaches. We here tested whether experimental exposure to chronic traffic noise affected parental behaviour and reproductive success in offspring number and growth in an important model of avian development, the zebra finch (Taeniopygia guttata). In a counterbalanced repeated-measures design, breeding pairs experienced continuous playbacks of one of two types of highway noise that previous spatial choice tests had shown to be neutral (control) or aversive. We monitored offspring development and parental feeding rates and nest attendance. Parental nest attendance was positively correlated with feeding effort and was higher in the aversive than in the control sound treatment and this effect was more pronounced for parents attending larger broods. However, neither noise condition affected offspring number, growth or body mass. There was also an absence of an effect of noisy conditions on these reproductive parameters when we combined our data with two other comparable studies in the same species in a meta-analysis. We discuss whether the increased parental engagement is a potential compensatory strategy that alleviated direct noise effects on the chicks. However, impaired parent-offspring or within-pair communication could also have increased parents nest attendance time. Future work is required to test these possible explanations and investigate potential long-term costs of increased parental engagement.
The rapid development of transport infrastructure is a major threat to endangered species worldwide. Roads and railways can increase animal mortality, fragment habitats, and exacerbate other threats to biodiversity. Predictive models that forecast the future impacts to endangered species can guide land-use planning in ways that proactively reduce the negative effects of transport infrastructure. Agent-based models are well suited for predictive scenario testing, yet their application to endangered species conservation is rare. Here, we developed a spatially explicit, agent-based model to forecast the effects of transport infrastructure on an isolated tiger (Panthera tigris) population in Nepal's Chitwan National Park--a global biodiversity hotspot. Specifically, our model evaluated the independent and interactive effects of two mechanisms by which transport infrastructure may affect tigers: (a) increasing tiger mortality, e.g., via collisions with vehicles, and (b) depleting prey near infrastructure. We projected potential impacts on tiger population dynamics based on the: (i) existing transportation network in and near the park, and (ii) the inclusion of a proposed railway intersecting through the park's buffer zone. Our model predicted that existing roads would kill 46 tigers over 20 years via increased mortality, and reduced the adult tiger population by 39% (133 to 81). Adding the proposed railway directly killed 10 more tigers over those 20 years; deaths that reduced the overall tiger population by 30 more individuals (81 to 51). Road-induced mortality also decreased the proportion of time a tiger occupied a given site by 5 years in the 20-year simulation. Interestingly, we found that transportation-induced depletion of prey decreased tiger occupancy by nearly 20% in sites close to roads and the railway, thereby reducing tiger exposure to transportation-induced mortality. The results of our model constitute a strong argument for taking into account prey distributions into the planning of roads and railways. Our model can promote tiger-friendly transportation development, for example, by improving Environmental Impact Assessments, identifying ``no go'' zones where transport infrastructure should be prohibited, and recommending alternative placement of roads and railways.
Conservation of large carnivores requires preservation of extensive core habitats and linkages among them. The goal of this study was to identify core habitats and corridors by predicting habitat suitability (an ensemble approach), and calculating resistant kernel and factorial least-cost path modeling for a relatively unknown carnivore, the striped hyaena in Khuzestan area in southwestern Iran. We used the procedure of spatial randomization test to evaluate the coincidence of striped hyaena road crossing with the predicted corridors. The results revealed that elevation, distance to conservation areas, categorical climate and grasslands density were the most influential variables for predicting the occurrence of the striped hyaena in the study area. In the estimated dispersal distance of 70 km, four core habitats were identified. The largest core habitat was located in the northeast of the study area with the highest connectivity contribution. Only about 12% and 1.5% of core habitats and corridors were protected by conservation areas, respectively. Predicted corridors, crossed by roads represented a high risk for striped hyaenas. Adaptive management plan throughout the landscape (conservation of core habitats and corridors, and reducing species mortality on the roads) must be considered by wildlife managers in Iran.
Roads can block animal movement and reduce persistence of species living in road surroundings. Movement restrictions on local populations may even increase extinction risk of abundant small mammals. However, road verges (road managed area between
the edge of the road and the beginning of private land) may provide refuge and corridors for small mammals when properly managed. Information on the effects of roads and roadside management on small-mammal movement is still scarce for low traffic roads (< 20000 vehicles per day) crossing well-preserved habitats. We aimed to fill this gap by comparing fine-scale movement patterns of wood mice (Apodemus sylvaticus ) in a road and in a similar roadless area without management. Both areas consisted of a well-preserved Mediterranean agro-silvo pastoral system. We studied several movement patterns: road crossings, verge use, length, and direction of
movement. Additionally, we assessed how roadside management, animals’ sex and residency status, season and microhabitat affect movement at the road area. At the roadless area, we defined a virtual road and verges at equivalent locations to the road area for comparison purposes. We gathered capture-mark-recapture data for two years to characterize movement patterns. Wood mice tended to avoid the road by crossing it less often and moving away from it more frequently than from equivalent locations in the roadless area. Wood mice used road verges more frequently than virtual verges and moved more often parallel to the road than to the virtual road. Road crossings
were more frequent after firebreak openings (strips of mowed land) in surrounding areas and near taller shrubs. Also, males used road verges more often than females. Differences on several movement patterns between areas and their trends within the road area can be explained mainly by the presence of the road and roadside vegetation management (e.g., firebreaks openings). We suggest roadside vegetation management practices (e.g., avoid land mowing; maintain vegetation strips) to promote the role of verges as refuges and/or corridors for small mammals.
Voetafdrukindicatoren geven inzicht in de impacts van consumptie en productie op milieu en natuur. In het rapport ‘Trends in Nederlandse voetafdrukken’ uit 2015 is dat al uitgebreid beschreven. Voor een aantal recente PBL-publicaties, te weten de Integrale Circulaire Economie Rapportage 2021, de Klimaat- en Energieverkenning 2020 en het rapport ‘Halveren van de Nederlandse voetafdruk’, zijn drie veel gebruikte voetafdrukindicatoren geactualiseerd voor de periode 2005-2015. Dit rapport beschrijft het model, de gebruikte database en de uitkomsten van de nieuwe berekeningen en dient daarmee als verantwoording voor de voetafdrukcijfers in de genoemde publicaties.
Chronic traffic noise is increasingly recognised as a potential hazard to wildlife. Several songbird species have been shown to breed poorly in traffic noise exposed habitats. However, identifying whether noise is causal in this requires experimental approaches. We tested whether experimental exposure to chronic traffic noise affected parental behaviour and reproductive success in zebra finches (Taeniopygia guttata). In a counterbalanced repeated-measures design, breeding pairs were exposed to continuous playback of one of two types of highway noise previously shown to be either neutral (control) or aversive. Parental nest attendance positively correlated with feeding effort and was higher for the aversive than the control sound and this effect was more pronounced for parents attending larger broods. However, neither noise condition affected offspring number, growth or body mass. The absence of an effect held when we combined our data with data from two other comparable studies into a meta-analysis. We discuss whether the increased nest attendance could be a compensatory strategy that alleviated detrimental noise effects on the chicks, and whether it could be caused by impaired parent-offspring or within-pair communication. Future work should test these hypotheses and investigate potential long-term costs of increased parental engagement.
Climate change impact had given rise to incessant flooding exacerbated by high tidal fluctuations, sea level rise and its accompanying negative impacts such as land degradation and seawater incursion into freshwater sources. Hence, the need to assess the hydrochemistry and anthropogenic pollutants in water, sediment and representative fish samples of Ayetoro coastal waters. Thirteen sampling stations (including 2 groundwater stations and 3 control stations) were selected to determine the concentration and spatial distributions of hydro-chemical characteristics and heavy metals concentrations. The results of the ionic concentrations (e.g., Calcium Ca 2+ ,Magnesium Mg 2+ ,Sodium, Na + , Potassium K + , Nitrate NO 3-, Phosphate PO 4 3-, Sulphate SO 4 2-and Chloride Cl-) further showed higher values that exceed the World Health Organization (WHO) standard, Federal Environmental Protection Agency (FEPA), and Federal Ministry of Environment (FEMENV) permissible limit for portable water and coastal water for marine life sustainability. The result further affirms the high impact of land degradation and saline water intrusion. Low pH, Dissolved Oxygen (DO) at some stations indicate increased anthropogenic activities. Heavy metal analysis further showed high Lead (Pb) concentrations in water, Copper (Cu), Manganese (Mn), Chromium (Cr) in sediment and Cu, zinc (Zn), Pb, cadmium (Cd), cobalt (Co) and Nickel (Ni) in representative fish samples. This study establishes that sea-level rise, land degradation, flooding and human-induced anthropogenic activities have negatively impacted Ayetoro community, hence an urgent need for bioremediation.
We attempted a complete review of the empirical literature on effects of roads and traffic on animal abundance and distribution. We found 79 studies, with results for 131 species and 30 species groups. Overall, the number of documented negative effects of roads on animal abundance outnumbered the number of positive effects by a factor of 5; 114 responses were negative, 22 were positive, and 56 showed no effect. Amphibians and reptiles tended to show negative effects. Birds showed mainly negative or no effects, with a few positive effects for some small birds and for vultures. Small mammals generally showed either positive effects or no effect, mid-sized mammals showed either negative effects or no effect, and large mammals showed predominantly negative effects. We synthesized this information, along with information on species attributes, to develop a set of predictions of the conditions that lead to negative or positive effects or no effect of roads on animal abundance. Four species types are predicted to respond negatively to roads: (i) species that are attracted to roads and are unable to avoid individual cars; (ii) species with large movement ranges, low reproductive rates, and low natural densities; and (iii and iv) small animals whose populations are not limited by road-affected predators and either (a) avoid habitat near roads due to traffic disturbance or (b) show no avoidance of roads or traffic disturbance and are unable to avoid oncoming cars. Two species types are predicted to respond positively to roads: (i) species that are attracted to roads for an important resource (e.g., food) and are able to avoid oncoming cars, and (ii) species that do not avoid traffic disturbance but do avoid roads, and whose main predators show negative population-level responses to roads. Other conditions lead to weak or non-existent effects of roads and traffic on animal abundance. We identify areas where further research is needed, but we also argue that the evidence for population- level effects of roads and traffic is already strong enough to merit routine consideration of mitigation of these effects in all road construction and maintenance projects.
We attempted a complete review of the empirical literature on effects of roads and traffic on animal abundance and distribution. We found 79 studies, with results for 131 species and 30 species groups. Overall, the number of documented negative effects of roads on animal abundance outnumbered the number of positive effects by a factor of 5; 114 responses were negative, 22 were positive, and 56 showed no effect. Amphibians and reptiles tended to show negative effects. Birds showed mainly negative or no effects, with a few positive effects for some small birds and for vultures. Small mammals generally showed either positive effects or no effect, mid-sized mammals showed either negative effects or no effect, and large mammals showed predominantly negative effects. We synthesized this information, along with information on species attributes, to develop a set of predictions of the conditions that lead to negative or positive effects or no effect of roads on animal abundance. Four species types are predicted to respond negatively to roads: (i) species that are attracted to roads and are unable to avoid individual cars; (ii) species with large movement ranges, low reproductive rates, and low natural densities; and (iii and iv) small animals whose populations are not limited by road-affected predators and either (a) avoid habitat near roads due to traffic disturbance or (b) show no avoidance of roads or traffic disturbance and are unable to avoid oncoming cars. Two species types are predicted to respond positively to roads: (i) species that are attracted to roads for an important resource (e.g., food) and are able to avoid oncoming cars, and (ii) species that do not avoid traffic disturbance but do avoid roads, and whose main predators show negative population-level responses to roads. Other conditions lead to weak or non-existent effects of roads and traffic on animal abundance. We identify areas where further research is needed, but we also argue that the evidence for population-level effects of roads and traffic is already strong enough to merit routine consideration of mitigation of these effects in all road construction and maintenance projects.
Studies conducted in the Prudhoe Bay, Alaska area since the 1970s suggested that Arctic Fox (Alopex lagopus) populations may have increased as a result of oil field development. During 1993, we estimated fox den densities within the Prudhoe Bay area and compared our estimates with those made previously in the same area and from other Arctic areas. The number of natal fox dens was stable between 1992 (n = 25) and 1993 (n = 26), as was mean litter size (4.6 and 4.4 pups per litter in 1992 and 1993, respectively). Fox den density was greater (1/15.2 km2) within developed areas than on adjacent undeveloped tundra (1/28.1 km2), and foxes used culverts and road embankments as den sites in addition to natural dens. Densities of fox dens in Prudhoe Bay development area and adjacent tundra were within the range of density estimates found in other Arctic areas.
Environmental disturbance can affect use of home range by large, free-ranging ungulates, but quantitative assessments of such effects are rare. We compared seasonal and annual use of range and habitat in the population of elk (Cervus elaphus) at Line Creek in southcentral Mortana, 1988-1991, before, during, and after installation of an oil well. Use of range by elk during the post-drilling period in autumn was different from use during drilling and pre-drilling periods, but use of range also changed during the same periods in another local population of elk not subjected to disturbance from oil drilling. Use of range grid cells containing or adjacent to the well site declined during the post-drilling period, but seasonal and annual sizes in range and boundaries for the population were similar in all periods. Distances between individually marked elk did not differ across periods, suggesting that drilling did not affect the social stability of elk. Use of forest habitats in autumn increased after initiation of drilling. Results suggested that elk compensated for site-specific environmental disturbance by shifts in use of range, centers of activity, and use of habitat rather than abandonment of range.
Roadside raptor surveys were conducted in November 1991 along 1224 km in the northern Argentinean Patagonia. Twelve species and 477 individuals were observed. The most common species were Chimango Caracaras (Milvago chirnango) (N = 243) and Black Vultures (Coragyps atratus) (N = 72). Raptor abundance and diversity index were highest in lowland valleys and in grassy hills near the Andean cordillera. Shrubsteppe zones near other habitats had higher raptor abundance and lower diversity than inner steppe areas. The Andean woodlands had the lowest raptor abundance. We suggest that deforestation of Andean woodlands and other human-induced alterations may have had positive effects on raptor open land abundance.
Increased predation has been suggested as a proximate factor causing the decline of vertebrate diversity in many human-altered landscapes. Previous studies on this topic have provided conflicting results, perhaps as a consequence of the limited spatial scale used in these investigations. We incorporated a multiscaled approach (using site, plot (1.44 km(2)), and landscape (54 km(2))) to investigate the distribution of activity of medium-sized carnivores relative to habitat edges and the numeric responses of these predators to habitat diversity. Among the taxa surveyed, raccoons (Procyon lotor) did not show an affinity for habitat edges at any spatial scale. However, raccoons were more abundant in landscapes characterized by a diversity of cover types. Free-ranging domestic dogs (Canis familiaris) and cats (Felis domesticus) did not respond to the proximity of habitat edges in summer but showed a strong affinity for edge habitats (especially those associated with human dwellings) during winter. Wild canids (Vulpes vulpes and Canis latrans) also selected sites in close proximity to edges in winter and were more abundant in diverse landscapes. Although human-dominated habitats (agricultural areas, grass-brushland, and developed sites) represented only 7-27% of the three landscapes studied, populations of generalist predators (raccoons and wild canids) increased as landscapes became more diverse. As a result, even moderate levels of habitat fragmentation may elevate predation rates and subsequently alter the composition of prey communities.
The effect of traffic noise on the breeding density of 20 passerine species was examined over a 2-year period in three different road types passing through pasture-woodlands in western-central Spain. No statistically significant differences were observed during the 2 years studied. An average of 19.6 birds/10 ha was recorded for the low-traffic road (LT), 21.7 birds/10 ha for the medium-traffic road (MT) and 19.1 birds/10 ha for the high-traffic road (HT). A total of 11 species (55%) did not show any statistically significant differences in breeding density among the different types of roads. By contrast, other species, such as the Blackbird, the Iberian Shrike and the Linnet, did point to differences between the MT and HT roads. House and Rock Sparrows, as well as the Corn Bunting, showed higher breeding densities near the HT road. The opposite effect was observed for the Wheatear, the Iberian chiffchaff and the Woodlark, for which high breeding densities were recorded in the vicinity of the LT road. Our results suggest that traffic noise constitutes a serious problem for at least 15% of the breeding bird community.
There is concern that caribou (Rangifer tarandus) may avoid roads and facilities (i.e., infrastructure) in the Prudhoe Bay oil field (PBOF) in northern Alaska, and that this avoidance can have negative effects on the animals. We quantified the relationship between caribou distribution and PBOF infrastructure during the post-calving period (mid-June to mid-August) with aerial surveys from 1990 to 1995. We conducted four to eight surveys per year with complete coverage of the PBOF. We identified active oil field infrastructure and used a geographic information system (GIS) to construct ten 1 km wide concentric intervals surrounding the infrastructure. We tested whether caribou distribution is related to distance from infrastructure with a chi-squared habitat utilization-availability analysis and log-linear regression. We considered bulls, calves, and total caribou of all sex/age classes separately. The habitat utilization-availability analysis indicated there was no consistent trend of attraction to or avoidance of infrastructure. Caribou frequently were more abundant than expected in the intervals close to infrastructure, and this trend was more pronounced for bulls and for total caribou of all sex/age classes than for calves. Log-linear regression (with Poisson error structure) of numbers of caribou and distance from infrastructure were also done, with and without combining data into the 1 km distance intervals. The analysis without intervals revealed no relationship between caribou distribution and distance from oil field infrastructure, or between caribou distribution and Julian date, year, or distance from the Beaufort Sea coast. The log-linear regression with caribou combined into distance intervals showed the density of bulls and total caribou of all sex/age classes declined with distance from infrastructure. Our results indicate that during the post-calving period: 1) caribou distribution is largely unrelated to distance from infrastructure; 2) caribou regularly use habitats in the PBOF; 3) caribou often occur close to infrastructure; and 4) caribou do not appear to avoid oil field infrastructure.
We investigated terrain preferences of caribou (Rangifer tarandus granti) in an oilfield region near Prudhoe Bay, Alaska. Under disturbance-free conditions, the distribution of calving caribou determined by aerial transect surveys was correlated with indices of terrain ruggedness based on map contours. Caribou preferred quadrats dominated by fine- textured rugged terrain, particularly when present in large clusters, and avoided quadrats with flatter terrain. Displacement of maternal females from a zone within 4 km of roads and production-related facilities reduced use of rugged terrain types in that zone by 52%; the remaining preferred terrain was scattered and less accessible. This reduction was accompanied by a 43% increase in caribou use of rugged terrain 4-10 km from surface development. Given that terrain ruggedness is positively correlated with forage quality and biomass availability, combined underuse and overuse of these important habitats may compromise summer nutrition of lactating female caribou, thereby depressing body condition and, hence, subsequent reproductive success.
Previous research in the Milne Point oilfield in northern Alaska showed that the density of caribou (Rangifer tarandus) in the calving period within 1 km of a road was significantly lower after construction than before construction of the road. This was interpreted as displacement from the road and a functional loss of habitat and has been extensively cited as a documented effect of oilfield development on caribou. We continued this study with additional aerial surveys flown during 1991-2001 and compared caribou numbers and density in 6 1-km intervals from the road over 3 time periods: pre-road construction (1978-1981), early post-road construction (1982-1987), and recent post-road construction (1991-2001). During the recent post-road period, the densities of calves and of all caribou were not significantly lower within 1 km of the road than the densities in the pre-road period. In addition, calf density was higher in the interval within 1 km of the road than in the intervals 1-6 km from the road during the recent post-road construction period. The total number of calving caribou observed in the study area has declined since pre-road construction and early post-road periods, but we found no evidence that caribou using the area during calving avoided areas near the road during the recent post-road period. Numbers of caribou in the study area during the post-calving period (after 20 June) during 1991-2001 were highly variable, but generally were higher than during calving. Analyses of relationships between calving and post-calving caribou densities and distance intervals from Milne Point Road suggested that distributions of calves and adult caribou were not strongly influenced by presence of the road.
Trapping was used to investigate small-mammal community composition of a
cleared powerline corridor compared with that of surrounding tropical
rainforest in the wet tropics of north-eastern Queensland and to determine
whether movements from the rainforest across the corridor were inhibited. The
dense exotic grassland of the cleared powerline corridor supported a
small-mammal community composed mainly of the grassland species
Melomys burtoni (73·3%) and
Rattus sordidus (15·0%) with rainforest
small mammals being restricted to woody-weed thickets along the
rainforest–powerline corridor edge. The rainforest species
Rattus sp. (80·3%),
Melomys cervinipes (10·9%) and
Uromys caudimaculatus (8·8%) comprised the
small-mammal community of the forest interior. These rainforest species also
inhabited rainforest edge habitat and regrowth rainforest connections across
gullies. Movements of rainforest species across the grassland corridor were
almost completely inhibited even under bait inducement, a result attributable
to the substantial structural and microclimatic habitat differences within the
clearing and to interspecific competition with the better-adapted species of
the grassland community. Rainforest species used regrowth connections along
gullies to cross the powerline corridor. Mitigation of the fragmentation
effects caused by powerline grassy swathes can best be achieved by
strengthening extant canopy connections in regrowth gullies, and by
establishing new connections across the clearings.
Exploring the possible reasons for heterogeneity between studies is an important aspect of conducting a meta-analysis. This paper compares a number of methods which can be used to investigate whether a particular covariate, with a value defined for each study in the meta-analysis, explains any heterogeneity. The main example is from a meta-analysis of randomized trials of serum cholesterol reduction, in which the log-odds ratio for coronary events is related to the average extent of cholesterol reduction achieved in each trial. Different forms of weighted normal errors regression and random effects logistic regression are compared. These analyses quantify the extent to which heterogeneity is explained, as well as the effect of cholesterol reduction on the risk of coronary events. In a second example, the relationship between treatment effect estimates and their precision is examined, in order to assess the evidence for publication bias. We conclude that methods which allow for an additive component of residual heterogeneity should be used. In weighted regression, a restricted maximum likelihood estimator is appropriate, although a number of other estimators are also available. Methods which use the original form of the data explicitly, for example the binomial model for observed proportions rather than assuming normality of the log-odds ratios, are now computationally feasible. Although such methods are preferable in principle, they often give similar results in practice. Copyright © 1999 John Wiley & Sons, Ltd.
This paper analyses the relationship between global geopolitical stability and environmental pressures in a 50-year scenario. Many environmental pressures in developing countries are directly or indirectly associated with infrastructure development related to multinational networks of mining, logging, petroleum and dam operations. Deforestation and regulation of rivers for hydropower and irrigation put enormous pressures on amount and quality of water resources through removal of natural filtering systems, loss of biodiversity, and affects the access of billions of people to water. Currently humans have directly converted and impacted more than 48% of the global terrestrial area as an indirect result of road development. With continued levels of development, 80–90% of the global environment, <90% of tropical forests and <60% of the Arctic will receive similar levels of disturbance around year 2050 as a result of infrastructure development and associated human activity. The current projections indicate that the impacts on the environment and people will become the highest in regions of central energy interests, including the Middle East, the Caspian Basin, the Mexico-Amazon corridor, Central Africa, and South-East Asia. These areas are characterized by environmental pressures from industrial development, and are the homes of <2 billion people living for >2 USD a day, 2/3 of the worlds conflicts, >80% of all internal refugees in the world, and are also subject to most of the recent increases in extreme natural weather-related disasters. With globalisation, infrastructure expansion no longer necessarily results in corresponding economic and social development at the same geographic location. Of a projected population increase of 3.3 billion people the next 50 years, 98% of this will take place in developing countries, while <90% of the increase in GDP/capita will take place timber, oil or minerals increased substantially in the last decade. Increasing inequity, corruption and environmental degradation may increase social instability. The outcome may become growing risk of terrorism and armed conflicts in these regions. This, in turn, is likely to increase the industrial focus on the Arctic as a region of potential low geopolitical risk for petroleum and mineral extraction. The subsequent development of the Arctic through piecemeal development may seriously threaten ecosystems, wildlife and indigenous peoples. There is an urgent demand for a global framework for regulating and mapping the rapidly expanding piecemeal development in infrastructure and increased transparency in capital flows.
Roadside habitats are important for a range of taxa including plants, insects, mammals, and birds, particularly in developed countries in which large expanses of native vegetation have been cleared for agriculture or urban development. Although roadside vegetation may provide suitable habitat for many species, resident animals can be exposed to high levels of traffic noise, visual disturbance from passing vehicles, and the risk of collision with cars and trucks. Traffic noise can reduce the distance over which acoustic signals such as song can be detected, an effect known as acoustic interference or masking. Studies from the northern hemisphere show that the singing behavior of birds changes in the presence of traffic noise. We investigated the impact of traffic noise and traffic volume on two species of birds, the Grey Shrike-thrush (Colluricincla harmonica) and the Grey Fantail (Rhipidura fuliginosa), at 58 roadside sites on the Mornington Peninsula, southeastern Australia. The lower singing Grey Shrike-thrush sang at a higher frequency in the presence of traffic noise, with a predicted increase in dominant frequency of 5.8 Hz/dB of traffic noise, and a total effect size of 209 Hz. In contrast, the higher singing Grey Fantail did not appear to change its song in traffic noise. The probability of detecting each species on a visit to a site declined substantially with increasing traffic noise and traffic volume, with several lines of evidence supporting a larger effect of traffic noise. Traffic noise could hamper detection of song by conspecifics, making it more difficult for birds to establish and maintain territories, attract mates and maintain pair bonds, and possibly leading to reduced breeding success in noisy roadside habitats. Closing key roads during the breeding season is a potential, but untested, management strategy to protect threatened bird species from traffic noise and collision with vehicles at the time of year when they are most vulnerable to their impacts. Other management options include reducing the speed and/or volume of traffic on such roads to an acceptably low level. Ours is the first study to investigate the effect of traffic noise on the singing behavior of birds in the southern hemisphere.
We investigated the use by Brown-headed Cowbirds (Molothrus ater) of five forest edge types and the forest interior of Green Ridge State Forest in the ridge and valley physiographic province of Maryland. Habitats were sampled, and breeding birds counted at each site. Cowbirds were detected in all habitats except forest interior; occurring most frequently in forest-brush (50.0% of points), -stream (46.3%), and -powerline (33.3%) edges. Among edge types, snag BA was also significantly (P < 0.01) higher at forest-powerline, -brush, and -stream edges than at forest-open road and -closed road edges. These habitats had high total vegetation volume (TVV), with which bird and host species abundances were positively associated. However, high TVV was not always indicative of high snag BA. With all habitats combined, bird species abundance, total vegetation volume (TVV), and foliage height diversity (FHD) at a height of 1-2 m were significantly (P < 0.05) higher at points where cowbirds were detected than at those where they were not detected, however only bird species abundance remained significant (P = 0.059) when forest interior was removed from the analysis. We propose that cowbirds in western Maryland select breeding areas based on: (1) distinct visible edges formed by canopy openings in the forest landscape, (2) occurrence of both high snag BA and high TVV at the forest edge, and (3) presence of high bird species abundance.
In forested plots adjacent to power-line corridors in E Tennessee, Acadian flycatcher Empidonax virescens and ovenbird Seiurus aurocapillus were significantly denser in forest interior. Summer tanager Piranga rubra, northern cardinal Cardinalis cardinalis and rufous-sided towhee Pipilo erythrophthalmus were denser near the edge. Densities of 17 other species were not significantly associated with distance from the edge. -from Author
We distributed questionnaires to 50 state natural resource agencies in October 1992 to request estimates of deer killed annually on highways, the source of the estimates, and information about methods used to reduce vehicle collisions with deer; 43 agencies responded. Statistics on deer killed by vehicles were highly variable among agencies and were inconsistent among agencies. Despite a limited quantitative basis, the national deer road-kill for 1991 conservatively totaled at least 500,000 deer. Deer road- kills had increased during 1982-1991 in 26 of 29 states that had suitable trend data. Nearly all states had used some type of signs, modified speed limits, fencing, over- and underpasses, reflective apparatus, habitat alteration, or public awareness programs, but few agencies had evaluated performance of those techniques. Approaches that alter deer behavior and movement patterns appear to be the most fruitful for future application anti evaluation.
Roads through tropical forest create linear disturbances that have unknown consequences for forest birds. We studied how a narrow, rarely used road through otherwise undisturbed Amazonian forest affected the movements and area requirements of understory birds that form mixed-species flocks. Differences in road maintenance led to two distinct treatments along the same road. Trees along the "closed" road formed a partial canopy connecting the two sides of the road, although the roadway itself was kept open. The "open" road was regularly maintained, making a complete opening 10-30 m wide. We followed 15 flocks, 5 each in interior forest, along the open road, and along the closed road. These flocks were led by Thamnomanes antshrikes, and each flock had a discreet, permanent territory. Flock territory size (mean = 8.5 ba) did not differ among the three locations. The open road formed the territorial boundary for all five flocks, although birds moved within a few meters of the edge of the road. Tbe closed road was less of a barrier: 2 of 5 flocks used both sides of the closed road. Playback experiments showed that flocks readily crossed the closed road to approach agonistic vocalizations. Along the open road, even though birds responded to playback by becoming agitated and moving to the extreme edge of the roadside vegetation, they were less likely to cross the road and did so only after a longer duration of playback. Our results suggest that flocks respond to a road as they would to a long linear gap. They use the vegetation along the edges of the road, but because they are unwilling to cross the open area, it becomes a flock territory boundary. Similarly, as in forest gaps, successional change along the closed road produced suitable habitat for flocks. Although this suggests that roads are a trivial problem, we caution that this result applies only to narrow roads that are not accompanied by deforestation or other disturbance.
Abstract A huge road network with vehicles ramifies across the land, representing a surprising frontier of ecology. Species-rich roadsides are conduits for few species. Roadkills are a premier mortality source, yet except for local spots, rates rarely limit population size. Road avoidance, especially due to traffic noise, has a greater ecological impact. The still-more-important barrier effect subdivides populations, with demographic and probably genetic consequences. Road networks crossing landscapes cause local hydrologic and erosion effects, whereas stream networks and distant valleys receive major peak-flow and sediment impacts. Chemical effects mainly occur near roads. Road networks interrupt horizontal ecological flows, alter landscape spatial pattern, and therefore inhibit important interior species. Thus, road density and network structure are informative landscape ecology assays. Australia has huge road-reserve networks of native vegetation, whereas the Dutch have tunnels and overpasses perforating road barriers to enhance ecological flows. Based on road-effect zones, an estimated 15–20% of the United States is ecologically impacted by roads.
Responses of deer (Odocoileus hemionus) and elk (Cervus canadensis) to roads were assessed by counting fecal-pellet groups near roads on winter ranges. Data were obtained in Colorado in shrub and pine habitats adjacent to paved, gravel, and dirt roads east of the continental divide; and in shrub and juniper woodland habitats west of the divide. Deer and elk avoid roads, particularly areas within 200 m of a road. Road avoidance was greater (1) east, rather than west, of the continental divide, (2) along more heavily traveled roads, (3) by deer, when compared to elk, and (4) for deer in shrub habitats when compared to pine and juniper habitats. Because of less snow accumulation, winter habitat is more available to cervids east of the continental divide where more pronounced avoidance of roads presumably results from a greater availability of habitat away from roads.
(1) The response of grizzly bears (Ursus arctos Ord) to gas exploration and timber harvest was investigated by comparing the locations of radio-collared individuals before, during, and after the activity in five tests. (2) In the first test, there was no significant difference in distribution of four bears involved in eleven bear-seismic situations over 3 years (data combined). In comparisons of within-year distributions of individual bears, two of the eleven bears showed a significant difference in habitat use. (3) Significant displacement was not found in the four other bear-industry interactions, including two seismic, one road maintenance and one timber-harvest activity. These activities all occurred in spring, when bears are more mobile than in summer. (4) The effect of industrial activity on the productivity of the test bears, the potential factors influencing the general lack of displacement, and management implications are discussed.