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The impacts of roads and other infrastructure on mammal and bird populations: A meta-analysis
... While the negative effects of urban areas certainly decrease with increasing distance from the urban periphery (Mcdonald et al., 2009;Benítez-López et al., 2010), not enough research has been conducted to determine if this relationship is linear or otherwise. For simplicity, we assumed urban impacts decrease linearly with increasing distance from the urban area (depending on the size of the population: Table 1). ...
... These combined effects can affect vertebrate distribution and abundance for up to 3,000 m either side of a road, with most impacts occurring closer to the road. Busier roads have wider-reaching impacts on biodiversity than narrower roads with lower traffic volume (see reviews in Reijnen et al., 1995;Forman et al., 2003;Riitters & Wickham, 2003;Benítez-López et al., 2010;Silva et al., 2012;Bennett, 2017). Therefore, our model assumes highways and secondary roads have impacts on arid vertebrates that attenuate linearly for 3,000 m and 1,000 m, respectively. ...
... A meta-analysis covering 234 bird and mammal species found that the impacts of powerlines and other infrastructure can be detected for up to a kilometer on bird populations and for up to five kilometers in mammals, with variation according to taxa and habitat type. Such avoidance behavior tends to be particularly strong in open habitats, such as arid environments, due to enhanced visibility (Benítez-López et al., 2010). In our model, we assumed that powerlines reduce biodiversity for up to 1 km with diminishing effect with distance. ...
Few arid nations have the baseline data needed to map high value habitat at local scales. We used remote sensing to model local habitat value across Saudi Arabia, an arid nation with degraded ecosystems and limited baseline data. First, we digitally mapped the ranges of Saudi Arabia's 199 high conservation priority terrestrial vertebrate species to produce a Conservation Priority Species Score for every point in the Kingdom. We then used ArcGIS to score five landscape attributes (to 30-m resolution) that correlate with vertebrate occupancy rates in arid ecosystems (urban development, land-use naturalness, hydrology, protected area status, and terrain complexity) to produce a Site Quality Score for every location. By multiplying the broadscale Conservation Priority Species Score by the local Site Quality Scores, we generated a Site Conservation Value Score for every location in Saudi Arabia. Modelled Site Conservation Value Scores correlated significantly with species counts from field surveys conducted at 12 sites, suggesting our model has value. We review the literature from arid ecosystems to test the assumptions inherent in our model and acknowledge the limitations of our approach. These results suggest our interim model can help identify local site value in arid ecosystems until more refined models are generated.
... Studies ought to concentrate on ecological patterns and processes using tests and simulation analysis to identify important impact thresholds, in order to produce useful recommendations and strategies for the development of infrastructure. To offer the fundamental information needed to create assessment methods and indexes, empirical research is required [1]. ...
... The speakers talked about measures that developers, financiers, lenders, and regulators can take to reduce or lessen the harm caused by new infrastructural projects [2]. Similar research was undertaken by to investigate the impacts of roads and other infrastructure on biodiversity [1]. The study used a meta-analytical approach to analyze data from 49 studies and 90 datasets, encompassing 201 bird species and 33 species of mammals, to determine the infrastructureeffect regions for bird and mammal populations. ...
... Although these relationships have been employed in a plethora of scientific publications, their full validity in biodiversity evaluations is constrained by geographical bias (88% of studies come from Europe and North America), taxonomic bias (only birds and mammals), an absence of distinction between infrastructure types and ecosystems types, and an ignorance of the effects of infrastructure-mediated changes on various functional categories. There is a need for an update on how wildlife population responds to infrastructure proximity [1]. ...
Research has been done to find ways to inhibit and put to an end the degradation facing wildlife due to human activities. Studies indicates that the billions of individuals on this planet are consuming resources more quickly than before. Methods to support the existence of wildlife in the territory should be put in place. Results in the article show that though these aspects are being taken into consideration, wildlife are still being affected by the anthropogenic activities that happen in the world. The goals of this research are to identify and assess the effects of various infrastructural projects on wildlife and other environmental factors and recommend suitable strategies to planning and design, wildlife management, and environmental protection to counteract any negative effects.
... Among the direct environmental threats posed by the unsustainable development of transportation networks are environmental fragmentation, leading to the loss of genetic diversity in the area, habitat loss, and increased animal mortality [59][60][61]. Many studies on that topic concern roads and highways [62,63] instead of railways. ...
... Railroads can act as physical or psychological barriers that impede or disrupt the natural movement and behaviour of wildlife, leading to fragmentation, isolation, and potential negative consequences for ecological connectivity. This barrier can act on large ungulates, birds, reptiles, small mammals, and insects, such as bumblebees [59,67,68]. ...
The development of railways stands as a pivotal milestone in the history of transportation, transforming the world and revolutionising the movement of people and goods. From their humble beginnings as rudimentary track systems to the sophisticated and interconnected networks we witness today, railways have played a crucial role in fostering economic growth, promoting globalisation, and shaping modern societies. Moreover, as the world grapples with the urgent need to mitigate climate change and transition to sustainable modes of transportation, the role of railways has gained significant attention. Railways have long been recognised as one of the most environmentally friendly means of mass transit, offering lower carbon emissions, energy efficiency, and reduced congestion compared to other transportation modes. However, there are still many challenges to overcome to provide continuous sustainability in the context of environmental impacts, especially related to wildlife and habitat protection. This scientific paper aims to explore the concept of sustainability in the context of railways, providing a comprehensive analysis of their environmental influences. As a result, the authors present a complex analysis of the topic, combining different perspectives—ecological, engineering, and legislative. They present methods of reducing noise pollution—constructional and legal ways; emission pollution reduction associated with combustion engines; and innovative analysis of limiting the impact of transportation on natural habitats and forest animal populations, which is not yet sufficiently elaborated scientifically in the literature. By examining key strategies, technologies, and policy frameworks, this research sheds light on the challenges and opportunities related to sustainability within the railway industry around the world.
... Direct effects of roads include mortality due to collisions with vehicles Grilo et al. 2021), disturbance of habitat close to roads (Benitez-Lopez et al. 2010;de Jonge et al. 2022), and impediment of movement (Chen & Koprowski 2019). In turn, movement impediment may affect migration patterns as well as gene flows within and among populations (Holderegger & Di Giulio 2010), thus increasing habitat fragmentation effects. ...
... In addition, the plans to upgrade a large number of existing roads in New Guinea (Government of Papua New Guinea 2018), which we did not consider in the future situation, could further increase habitat fragmentation. Moreover, we only quantified the effect of roads on habitat connectivity, whereas roads can have several other detrimental effects on species as well, such as mortality due to collisions with vehicles and disturbance of the habitat close to the roads (Laurance et al. 2009;Benitez-Lopez et al. 2010;Grilo et al. 2021;de Jonge et al. 2022). For example, a global study on roadkill data found that roadkill rates of some mammals were higher than 10 individuals per km road per year, posing a significant threat to the persistence of species (Grilo et al. 2021). ...
New Guinea is one of the last regions in the world with vast pristine areas and is home to many endemic species. However, extensive road development plans threaten the island's biodiversity. Here, we quantified habitat fragmentation due to both existing and planned roads for 139 terrestrial mammal species in New Guinea. For each species, we calculated the equivalent connected area (ECA) of habitat, a metric that takes into account both the area and the connectivity of habitat patches, for three situations: (1) no roads (baseline situation), (2) existing roads (current situation), and (3) existing and planned roads combined (future situation). On average across the species, the ECA in the current situation equals 89% (SD = 12%) of the baseline ECA values (i.e., a situation without roads) and the lowest remaining ECA was found for Shawmayer's coccymys ( Coccymys shawmayeri , 53%). The average remaining ECA decreases to 71% (SD = 20%) of the baseline ECA values in the future situation. Further, the future remaining ECA drops to below 50% of the baseline for 28 species and the lowest remaining ECA was found for the montane soft‐furred paramelomys ( Paramelomys mollis , 36%). Especially currently non‐threatened carnivorous species with a large body mass will experience a large reduction in ECA. Future road development plans thus imply extensive additional habitat fragmentation for a large number of terrestrial mammal species in New Guinea. It is therefore important to limit the impact of planned roads, for example by reconsidering the location of planned roads that intersect habitat of the most threatened species, or by the implementation of mitigation measures such as underpasses.
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... Land-use change and infrastructure development are increasing at an accelerating pace worldwide (Ibisch et al., 2016;Venter et al., 2016), including all global biodiversity hotspots (Hu et al., 2021), and are among the main causes of an unprecedented biodiversity decline (Benítez-López et al., 2010;IPBES, 2019;Newbold et al., 2015). Most infrastructure development takes place in areas already affected by multiple sources of disturbance (Barber et al., 2014) and, therefore, anthropogenic features are often clustered in the landscape. ...
... The formulation presented here can be used to model cumulative impacts of anthropogenic features not only on species' habitat selection, but on virtually all spatially explicit response variables, including population abundance (e.g. Benítez-López et al., 2010), species richness (e.g. Ficetola & Denöel, 2009), measures of biological diversity, community dynamics and ecological processes such as movements. ...
1. The concept of cumulative impacts is widespread in policy documents, regulations and ecological studies, but quantification methods are still evolving. Infrastructure development usually takes place in landscapes with preexisting anthropogenic features. Typically, their impact is determined by computing the distance to the nearest feature only, thus ignoring the potential cumulative impacts of multiple features. We propose the cumulative ZOI approach to assess whether and to what extent anthropogenic features lead to cumulative impacts.
2.The approach estimates both effect size and zone of influence (ZOI) of anthropogenic features and allows for estimation of cumulative effects of multiple features distributed in the landscape. First, we use simulations and an empirical study to understand under which circumstances cumulative impacts arise. Second, we demonstrate the approach by estimating the cumulative impacts of tourist infrastructure in Norway on the habitat of wild reindeer (Rangifer t. tarandus), a near-threatened species highly sensitive to anthropogenic disturbance.
3. In the simulations, we showed that analyses based on the nearest feature and our cumulative approach are indistinguishable in two extreme cases: when features are few and scattered and their ZOI is small, and when features are clustered and their ZOI is large. The empirical analyses revealed cumulative impacts of private cabins and tourist resorts on reindeer, extending up to 10 and 20 km, with different decaying functions. Although the impact of an isolated private cabin was negligible, the cumulative impact of ‘cabin villages’ could be much larger than that of a single large tourist resort. Focusing on the nearest feature only underestimates the impact of ‘cabin villages’ on reindeer.
4. The suggested approach allows us to quantify the magnitude and spatial extent of cumulative impacts of point, linear, and polygon features in a computationally efficient and flexible way and is implemented in the oneimpact R package. The formal framework offers the possibility to avoid widespread underestimations of anthropogenic impacts in ecological and impact assessment studies and can be applied to a wide range of spatial response variables, including habitat selection, population abundance, species richness and diversity, community dynamics and other ecological processes.
... Functional connectivity is particularly important for large, mobile animals (Benitez-López et al., 2010). Such species are prone to decline and extinction (Woodroffe and Ginsberg, 1998), especially where landscapes are altered or where permeability is diminished (Wilcove and Wikelski, 2008). ...
... Notably, northern trails are commonly associated with hunting (including hunting for caribou ;Freeman, 1976;Aporta, 2004Aporta, , 2009Aporta, , 2011, an activity with marked effects on the movement and range use of harvested species (Doherty et al., 2021;Ghoddousi et al., 2021). Our study area is open and treeless, and the impacts of humans occur over greater distances in these environments (Benitez-López et al., 2010). Because trails were moderately correlated with distance to [both] community and shipping routes (Table S5), however, we cannot discount that this pattern may be amplified by these associations and reflect cumulative effects. ...
Sea ice loss, disturbance, and habitat modification by humans can alter functional landscape connectivity, with negative impacts on wildlife. Connectivity facilitates movement and gene flow, and contributes to genetic diversity, metapopulation dynamics, and species range-shifts under climate change. For Arctic ungulates, which disperse over large areas including sea ice, environmental change threatens further isolation. Protecting habitat and its linkages is critical and depends on identifying such areas at commensurate, broad scales. Using caribou, the world's most vagile species, we modelled and mapped the drivers of connectivity across ca. 2 million km2 of the Canadian Arctic Archipelago — where the pace of climate change is among the fastest and caribou are threatened with extinction. First, we quantified hierarchical genetic structure and identified two discrete groups. Next, using circuit theory and simultaneous multi-surface optimization, we tested whether land- and sea-scape heterogeneity or geographic distance better accounted for movement and gene flow within each group. We show that anthropogenic interference is far-reaching. High Arctic Peary caribou displayed isolation-by-resistance, where glacier cover, low sea-ice concentrations during fall, and human trails impeded connectivity. In contrast, more southerly barren-ground caribou displayed largely unrestricted gene flow. These divergent outcomes underscore that organism-landscape relationships can vary across space and highlight the importance of intra-specific structure and responses. By leveraging genetic data, our study demonstrates how critical movement pathways can be identified, even for remote and imperilled species. Such knowledge supports broadscale conservation planning, in particular, by accounting for complex organism-landscape relationships, across vast, heterogeneous ecosystems.
... These infrastructures are well-recognized as linear intrusions. Today they are a threat to biodiversity and now one of the most significant worldwide threats to wildlife (Forman et al., 2003;Benítez-López et al., 2010;van der Ree et al., 2015). Intrusions, such as road, railway, and canal networks act as physical and behavioral barriers to the movement of wildlife and cause fragmentation of habitats. ...
... Finally, they disrupt Journal of Animal Diversity (2023) | © Lorestan University Press populations (Rajvanshi et al., 2001; Barrientos and Borda de Água, 2017). It is well established that road and railway tracks are one of the direct threats to many vertebrate species (Forman et al., 2003;Benítez-López et al., 2010;van der Ree et al., 2015). The impacts of roads and railways on herpetofauna have been extensively reviewed considering various aspects of threats (Vijaykumar et al., 2001;Andrews and Jochimsen, 2007). ...
Railway lines, roadways, canals, and electricity cable networks pose serious problems to wildlife, fragmenting habitats worldwide. These infrastructures are well-recognized as linear intrusions. Today they represent a threat to wildlife, including to the mugger or marsh crocodile (Crocodylus palustris Lesson, 1831). The current study documents 15 crocodile-vehicle collisions (CVCs) recorded in 2 years (2021 and 2022); 11 were on roads, and 4 were on railway tracks. Sex was determined for eleven individuals (five males, six females) and four were of undeterminable sex due to crushing. A total of thirteen individuals were found dead at the various sites of collision, and two juvenile individuals were found injured and one of them was treated successfully and returned to the wild. The highest number of CVCs (nine) occurred in Central Gujarat, followed by three CVCs in Saurashtra, two in the Kutch region, and one in North Gujarat. Mitigation measures required for the collision situations in Gujarat are discussed. A literature survey showed that a total of 75 CVCs were recorded within the last 18 years due to the state's road (n= 51, 68%) and railway (n= 24, 32%) networks, with the highest number of CVCs (56) observed in Central Gujarat and the lowest numbers of CVCs noted in North Gujarat (2) and South Gujarat (no CVCs). There was a high number of subadult and juvenile mugger CVC victims. The CVC site location in the different regions of Gujarat state positively corresponds to crocodile populations. However, the mugger crocodile (C. palustris) is nationally protected under the Indian Wildlife Act as a Schedule I species, and the IUCN criteria is 'Vulnerable' and it is an Appendix 1 (CITES) species; therefore, conservation measures are required. CVC incidences were recorded widely in the entire species distribution range, from Iran, India, and Sri Lanka, and can be considered as an emerging threat to mugger crocodiles.
... Habitat degradation and loss are among the biggest threats to biodiversity (Dirzo et al. 2014), and in this regard, roads are considered the most prevalent landscape alteration trigger since the early 20th century (Geneletti, 2003;Trombulak & Frissell, 2001), with an expansion up to 60% (25 million of kilometres) foreseen until 2050 . Such a considerable expansion is a matter of concern also due to the roads associated "Pandora' box" of many additional ecological problems: facilitated access to natural resources, accelerated deforestation, wildlife mortality, as well as encouraged speculative activities (Benítez-López et al, 2010;Gross, 2016;. The road expansion and construction phase represent a direct serious threat to wildlife (e.g., for species with low mobility; Trombulak & Frissell, 2001), even though mortality may also persist over longer term in the form of wildlife collisions with vehicles (Coffin, 2007;Forman et al., 2003;. ...
... The spatial and temporal extent to which roads negatively affect multiple taxa, in particular mammal and bird populations at the landscape level represent a research priority, given that this knowledge may greatly benefit a better green infrastructure design and more effective mitigation planning (Benítez-López et al., 2010;. The chapter 4 forms the cornerstone of the thesis in this regard, by integrating road ecology, remote sensing and landscape connectivity science within EIA-based modeling tools, developed to represent an essential guidance for increasing mitigation efficiency during the strategic planning phase (sensu . ...
Roads are a major threat to wildlife due to induced mortality and restrictions to animal movement. A central issue in conservation biology is the accurate site identification for the implementation of multispecies mitigation measures, on roads. Those measures entail high costs and methodological challenges and their efficiency highly depend on the right location. The aim of this PhD is to inform, through remote sensing and connectivity modelling, how to increase the efficiency of planning mitigation measures to reduce roadkill and promote connectivity; and demonstrate the usefulness of remote sensing in defining suitable areas for the conservation of an endangered species that often occurs in the vicinity of roads. To do so, we first assessed whether occurrence-based strategies were able to infer functional connectivity, compared to those more complex and financially demanding based on telemetry, with respect to daily and dispersal movements. Secondly, we assessed whether remote sensing data were sufficiently informative to identify key habitats for a threatened species around road verges. Thirdly, we assessed the predictive and prioritisation ability of road mitigation units intercepting multispecies corridors to prevent vulnerability to roadkill. Findings revealed that simple models are suitable as complex ones for both daily and dispersal movements, allowing for costly-effective connectivity assessments. Results demonstrated the ability of free remote sensing data to identify microhabitat conditions in verges and surrounding landscape, for a threatened rodent, allowing for the delimitation of refugee areas and definition of monitoring strategies for the species. Undemanding data (occurrence and remote sensing) were able to describe species-specific ecological requirements for birds, bats and non-flying mammals as well as roadkill patterns, possibly due to similar overlapping corridors and habitats, despite some mismatches that occurred for highly mobile species. This framework ensured high efficiency in prioritisation of multispecies roadkill mitigation planning, resilient to long-term landscape dynamics.
... Only 3% of the original Cerrado cover persists in São Paulo state (Nalon et al. 2020). Most of the remaining Cerrado and Atlantic Forest vegetation is immersed in a human-dominated matrix composed of pasture and agriculture (i.e., monocultures), and surrounded by the highest density of paved roads in Brazil (Durigan et al. 2007;CNT 2018;Oliveira et al. 2020), which has important implications for species persistence (Benítez-López et al. 2010). For example, P. concolor is the top-predator most killed by vehicle collision in this region (Abra et al. 2021). ...
Habitat loss and fragmentation threaten population persistence because they affect the ability of individuals to disperse between remaining patches of good-quality habitat and reduce refuge areas for populations. In cougars (Puma concolor), males are predominantly dispersers while females tend to be more philopatric. To examine the dispersal ability and philopatry of cougars in a human-dominated landscape in Brazil, we performed relatedness and spatial autocorrelation analyses based on genotyped cougars from different sampling groups: forest fragments within a human-modified matrix, continuous forest, and road-killed individuals. We found similarly high relatedness and a positive spatial autocorrelation at the shortest spatial scale (0-100 km) for both males and females from the forest fragments within a human-modified matrix. In the continuous forest and among cougars sampled as roadkills, we detected no spatial autocorrelation and observed low relatedness for both sexes. We also detected higher male:female sex ratio among road-killed individuals, likely due to the greater dispersal tendency of males. Our results confirm female philopatry in the forest fragments. However, the high relatedness and positive autocorrelation observed in the forest fragments suggest kin clustering also for males, which may be a result of unsuccessful dispersal. We reported the first evidence for a South American cougar population of unsuccessful dispersal in response to human-altered landscapes. Further research is needed to assess the specific causes of male unsuccessful dispersal and how it may affect species persistence in human-dominated landscapes.
... This process, driven by land expansion, has extensively utilized ecologically valuable areas, leading to the degradation of natural environments and the loss of critical ecosystem services [2,3]. These consequences contribute to global challenges like climate change and biodiversity loss [4]. The ecological costs associated with land urbanization are substantial [5], and the irreversible nature of this process means that restoring ecosystems to their original states may require significant long-term investments in labor and resources [6,7]. ...
The Yellow River Basin (YRB) stands as one of China’s most significant river basins, and the maintenance of its ecological functionality is of paramount importance for national well-being. The Guanzhong Plain Urban Agglomeration (GPUA), situated in the middle reaches of the YRB, represents the central hub of human activities. The rapid expansion of cities within this region poses formidable challenges to the ecological security framework of the highly sensitive middle reaches of the YRB. In this study, the dynamic equivalent coefficient method was employed to evaluate the changes in Ecological Service Values (ESVs) within the GPUA from 1990 to 2020, as well as the ecological costs incurred due to urban expansion. The results indicate the following: (1) Over the past three decades, the land-use pattern within the GPUA has undergone significant transformations. The area designated for urban development has expanded by a factor of 1.16 compared to its original extent, while the areas encompassing forests, shrubs, agricultural land, grassland, wetland, and bare land have experienced continuous reductions. (2) The ESV of the study area displays a declining trend initially, followed by a subsequent increase over the 30-year period. Forests play a predominant role in contributing to the ESV of the GPUA, with regulating services and supporting services standing out as the primary ecosystem functions. (3) The expansion of the GPUA between 1990 and 2020 has resulted in a net loss of 3772.10 km2 of ecological land. The ecological costs associated with urban expansion soar to an astonishing CNY 2.54 billion, with the highest costs attributed to the loss of hydrological regulation and soil conservation services; this issue demands significant attention. The outcomes of this research contribute to a better comprehension of the ecological costs and benefits that accompany the development of urban agglomerations in the middle reaches of the YRB. Furthermore, they provide invaluable insights for decision makers seeking to implement more effective strategies for sustainable land-use management.
... The sprawl of roads, transmission lines, and pipelines associated with relatively compact lease sites affect a disproportionate habitat area through fragmentation, edge effects, and other forms of degradation ( Trainor et al. 2016 ;Daniel and Koper 2019 ;Ott et al. 2021 ;Davis et al. 2023 ). For example, it is estimated that for every oil well, 100 ha of road is constructed ( Riley et al. 2012 ), and some of the ecological effects of these roads may extend up to 1 km ( Benítez-López et al. 2010 ). Roads cut through otherwise intact grassland landscapes and can act as corridors for invasive vegetation ( Forman and Alexander 1998 ;Gelbard and Belnap 2003 ), alter predator communities ( Frey and Conover 2006 ;Glass and Eichholz 2022 ), and create movement barriers for grassland bird species ( Londe et al. 2022 ). ...
North America's grassland birds remain in crisis despite decades of conservation effort s. This review provides an overview of factors contributing to these declines, as well as strategies and resources available to a diversity of stakeholders to help conserve grassland bird communities with an emphasis on the Great Plains-a grassland region of global ecological significance and a habitat stronghold for grassland birds. Grassland bird declines are driven by historical and continuing threats across the full annual cycle including grassland habitat loss, agriculture intensification, woody encroachment, and disruption of fire and grazing regimes. More recently, energy development activities, the use of neonicotinoid pesticides, and anthropogenic climate change have emerged as additional threats. While threats to grassland birds are numerous and often synergistic, possibilities for conservation are also diverse and multifaceted. Land set-aside programs, incentives and voluntary practices for producers, improved environmental management by energy and utility companies, and policy and regulation can all contribute to the conservation of these unique species. We suggest that future grassland bird research should focus on poorly studied aspects of the annual cycle, such as overwinter survival and habitat use, and the migratory period, which remains completely unexplored for many species. Filling these knowledge gaps may facilitate more sophisticated population modeling that can identify limiting factors and more effectively guide investment in conservation.
... Although roads are included in the major transportation land use class, their influence goes beyond the area of direct intervention, generating effects at different distances depending on the species or the effect evaluated (Benítez-López et al., 2010;Forman & Deblinger, 2000). Most naturalness indices use distance from roads as a separate variable from land use (Aplet et al., 2000;Sanderson et al., 2002;Woolmer et al., 2008). ...
Trail advocates argue that trails promote contact with nature, generate economic benefits for communities, and raise awareness about the importance of nature conservation. Mega trails, thousands of kilometers long crossing different regions, could spread these benefits for extensive landscapes, protecting important ecological and climate corridors. However, these benefits are poorly supported, and few studies evaluated whether these trails show effective conservation outcomes. This study uses a multidisciplinary approach to explore these outcomes and assess if mega trails are effective conservation tools. Based on extensive surveys and interviews along the three most renowned US national scenic trails – NST (Appalachian, Pacific Crest, and Continental Divide Trail) the influence of these trails on hikers, local communities, and landscapes is investigated. Regarding hikers, the results suggest that the longer the hiking experience, the stronger and broader the sense of place. Hikers motivated by NSTs present a stronger and broader sense of place, and this difference occurs even among day hikers, suggesting a brand effect. Mega trails help create meaning for extensive landscapes, facilitating the understanding of large-scale ecological processes. However, the path leading from sense of place to support for conservation and pro-environmental behavior is complex and seems to be mediated by a connection to nature as a whole. Mega trails also influence residents’ perceptions of trail benefits. Initiatives such as trail town programs and personal experiences influence the gateway communities’ residents’ perceptions more than economic benefits. The engagement of hikers, communities, and other actors to protect trail corridors, scenic views, and landscapes results in legal protection, land acquisition, and other land use actions. Trails with a high level of mobilization result in greater landscape connectivity and can be large corridors to allow species range shifts in response to climate change and habitat destruction. These findings suggest some guidelines for mega trail implementation worldwide, such as investing in the association of trail brands with geographical features or ecoregions and alternate routes to reach a diverse audience. Overall, when properly managed, mega trails seem to contribute to people’s awareness, community engagement, and habitat connectivity, corroborating the discourse in favor of mega trails as conservation tools.
... Moose and black bear also exhibit significant avoidance behavior of up to 1 km from human activity, including human presence, urban and industrial development, agriculture, and roads (Jalkotzy et al. 1997;Laurian et al. 2008). This disturbance distance, also referred to as the "zone of influence" and the "road effect zone", cause avoidance of, or displacement from, preferred habitats due to disturbances such as noise, light, pollutants, habitat degradation and other anthropogenic alterations (Forman and Alexander 1998;Benítez-López et al. 2010;Polfus et al., 2011). Between 2000 and 2018, the length of the road network within the Québec portion of the study area increased by 7684 km (16%), with primary road length increasing by 29%; and in the Ontario portion, the length of the road network increased by 2380 km (12%), with primary road length increasing by 13% (Cole et al. 2023). ...
Context
The Adirondack-to-Laurentians (A2L) transboundary wildlife linkage is one of three north–south movement linkages that connect natural areas in northeastern USA and southeastern Canada. This region still retains habitats of high ecological integrity and biodiversity; however, anthropogenic land transformation may be putting transboundary connectivity at risk.
Objectives
We measured the impacts of anthropogenic land transformation on species-specific habitat amount, fragmentation, and connectivity in the A2L between 2000 and 2015.
Methods
We developed suitable habitat and resistance models for the American black bear (Ursus americanus), fisher (Pekania pennanti), moose (Alces alces), and white-tailed deer (Odocoileus virginianus) to identify suitable and optimal habitat patches for each species. We quantified habitat amount, fragmentation, and connectivity, and used Linkage Mapper and Circuitscape to map corridors and pinch-points important for connectivity.
Results
In the A2L between 2000 and 2015, suitable and optimal habitat patch area declined considerably, fragmentation increased, and inter-patch connectivity decreased for each species. Moose and black bear habitat patches experienced the greatest habitat loss, fragmentation, and decline in inter-patch connectivity. The majority of habitat patch area loss and fragmentation occurred in the southern Québec and Ontario portions.
Conclusions
To achieve long-term functionality of the A2L, collaborative and coordinated measures will be necessary to preserve the integrity of the Québec mega-patch, restore extensive habitat in eastern Ontario, and reestablish or maintain connectivity throughout the linkage. Left unaddressed, continued anthropogenic land transformation is likely to have detrimental effects on the ability of the A2L to function as a transboundary wildlife linkage.
... Decreases in air traffic volume would reduce these stressors, making the airport environment more appealing to wildlife and, therefore, result in collision-enhancing changes to wildlife abundance and behavior. For birds within the airport environment, stressors such as chemical and noise pollution might also affect nesting decisions and reproductive success 17,21,22 , and reductions in air traffic volume might make near and on-airfield nesting more attractive. This potential mechanism is particularly relevant to our investigation since the most pronounced reductions in air traffic volume were coincident with the nesting and fledging of birds in most of the study area-i.e., March-July in the contiguous United States (Figs. ...
Exploiting unprecedented reductions in aircraft movements caused by the COVID-19 pandemic, we investigated the relationship between air traffic volume and the frequency of wildlife-aircraft collisions, or wildlife strikes, at the 50 largest airports in the United States. During the COVID-19 months of 2020 (March–December), both air traffic volume and the absolute number of wildlife strikes were reduced. The net effect of these two movements, however, was an increase in the wildlife strike rate from May 2020–September 2020. This increase was found to be most pronounced at airports with larger relative declines in air traffic volume. We concluded that the observed increase in the wildlife strike rate was, at least in part, generated by risk-enhancing changes in wildlife abundance and behavior within the airport environment. That is, wildlife became more abundant and active at airports in response to declines in air traffic volume.
... The global decline of biodiversity has reached an unprecedented rate, and infrastructure development to support a growing human population is a key driver (Rockström et al., 2009;Butchart et al., 2010;EEA-FOEN, 2011;McCallum, 2015). The variety of impacts that LTI has on biodiversity and ecosystems are well-described and include habitat loss, wildlife-vehicle collisions (WVCs) which kill and injure wildlife and motorists, creation of physical barriers, noise and light disturbance, the spread of pollution and invasive alien species, and changes in hydrology and microclimate (Forman et al., 2003;Benítez-López et al., 2010;van der Ree et al., 2015a). The increasing scale of impacts is exemplified by the prevalence of roads now fragmenting Earth's terrestrial surface into more than 600,000 patches, the majority less than one square kilometre in area (Ibisch et al., 2016). ...
The purpose of this technical report is to address ecological connectivity during the development of roads, railways and canals. To provide an overview of practical, feasible science-based strategies for Protected and Connected Area (PCA) managers, transport practitioners, industry, conservationists and other interested
stakeholders. It introduces and describes the numerous solutions that are available to support biodiversity and ecological connectivity conservation in, and adjacent to,
PCAs. It promotes best practices and provides details for the various phases of infrastructure development.
... The unprecedented expansion of linear infrastructure such as roads and rail is causing detrimental impacts on many wildlife populations around the world (Benítez-López et al., 2010;Forman and Alexander, 1998;Rytwinski and Fahrig, 2012;Torres et al., 2016). Roads affect wildlife directly via traffic-induced mortality (Abraham and Mumma, 2021), and indirectly through habitat loss, landscape fragmentation, and degradation (Engert et al., 2021;Laurance et al., 2014Laurance et al., , 2009. ...
Crossing structures are frequently installed worldwide to ameliorate the impacts of road and rail infrastructure on wildlife populations, yet their effectiveness is often uncertain. We monitored various species at multiple drainage culverts, dedicated wildlife underpasses, and a large viaduct, as well as in adjacent bushland over 12 months along a 13 km section of a new highway in eastern Australia. We quantified the frequency that species approached each structure relative to their presence in adjacent bushland, and compared species’ utilisation preferences between the three types of crossing structure. Of the 46 species detected, only 28 were detected at crossing structures. Brush turkeys (Alectura lathami), echidnas (Tachyglossus aculeatus), European brown hares (Lepus europaeus), rats (Rattus spp.), red-necked wallabies (Macropus rufogriseus) and swamp wallabies (Wallabia bicolor) were less frequently observed at crossing structures than in adjacent bushland. Feral cats (Felis catus) and European red foxes (Vulpes vulpes) were observed 3.5 and 2.7 times more frequently at crossing structures than in adjacent bushland. Culverts, underpasses and the viaduct performed equally for all species except for swamp wallabies and hares, which preferred the viaduct. Feral cats, foxes, dingoes (Canis familiaris), and hares were responsible for 76% of the successful crossings, and individually identified feral cats and foxes repeatedly crossed the road during the study period. We recommend increased use of experimental study designs to evaluate the effectiveness of crossing structures and provide construction authorities with reliable information on structure performance.
... Among many harmful effects, roads contribute to habitat loss and fragmentation, which are main causes for species decline and extinction (Forman et al., 2003;Fahrig and Rytwinski, 2009;Benítez-López et al., 2010). Species persistence on fragmented habitats depends on their ability to move (through a hostile environment) and reach suitable patches to access food, shelter, and mates (Gardiner et al., 2019). ...
Roads are often considered barriers to animal movement thereby reducing the persistence of species in their vicinity. Nonetheless, road verges may provide refuges or corridors for small mammals across highly human-modified landscapes. In these landscapes, road verges can be the last remnants of suitable habitats. However, in well-preserved habitats, road verges may show a similar vegetation structure to surrounding areas. In these circumstances, the effects of roads, road verges and roadside management on small-mammal conservation are still not clearly understood. These effects are expected to
depend on management practices on road surrounding land. This thesis aims to assess the effects of roads on demographic traits, movements patterns and landscape connectivity for small mammals in a well-preserved agro-silvo pastoral system. Populations of wood mice (Apodemus sylvaticus) were studied using capture-mark-recapture methods in a road area and in a similar roadless area. Extended Pollock’s robust design models were used to assess several population parameters. Movement patterns were evaluated by step analysis. Graph theory was used to quantify landscape connectivity. Road and roadside management decreased abundance and body condition, hampered road crossings, changed movement direction, and decreased overall landscape connectivity for wood
mice. Road verges provided habitat and pathways, promoting functional connectivity for this species in the road area. Nevertheless, road verges’ role depended on the vegetation management on verges and surrounding areas. The recommendations suggested in this work for roadside vegetation management also account for the potential increase in roadkill and fire risk. The outcomes of this thesis emphasize the importance of properly managing vegetation on road verges and surrounding private land for the conservation of small mammals in well-preserved habitats.
... Urban areas can be challenging for wildlife to inhabit, with many factors reducing their suitability (Grimm et al. 2008), including roads and traffic (Fahrig et al. 1995;Ben ıtez-Ló pez, Alkemade, and Verweij 2010;Claireau et al. 2019), fragmented and species-poor habitats (Krauss et al. 2010), as well as air quality, noise and light pollution (Kunc and Schmidt 2019;Murray et al. 2019;Owens et al. 2020). The UK is highly urbanized, with 83.9% of its population in urban areas, following an almost 3% increase over the past decade (O'Neill 2021). ...
Urbanization damages biodiversity, reducing people’s connection to nature and negatively impacting the survivability of local species. However, with small adjustments, the damage could be mitigated. In temperate regions, several bat species inhabit urban areas, and with urbanization set to increase, adapting urban areas to improve their suitability for bats is imperative. Therefore, we investigated if wooded streets and streetlight dimming in an urban setting influenced bat activity. Static bat detectors were used to compare wooded versus non-wooded, and bright versus dim streets in Leicester, UK, on predominantly residential streets. The collected calls were quantified into bat activity (passes per night). Six species were identified, but the common pipistrelle (Pipistrellus pipistrellus) was dominant, making up 94.1% of all calls, so it was the sole species included in the statistical model. Wooded streets had significantly higher bat activity than non-wooded streets, but bright and dim streets were not significantly different. The results suggest that wooded streets were being used as green corridors, with common pipistrelles possibly following them to conceal themselves from predators, such as the tawny owl, and the proliferation of wooded streets in urban areas could allow the formation of better-connected populations. Streetlight dimming did not affect bat activity, but no light-averse bats were detected, likely because even the most dimmed streets deterred them despite street lighting increasing food availability by attracting insects. Therefore, an alternate solution, such as part-night lighting, may be required to increase the suitability of urban areas to light-averse species.
... The negative effects of roads and other linear infrastructure on biodiversity have been documented for many decades (Stoner 1925, Forman andAlexander 1998). Over two hundred avian species have been reported to be affected by roads (Benítez-López et al. 2010). Of these, vultures can be attracted to roads (Meunier et al. 2000, Bautista et al. 2004, Lambertucci et al 2009. ...
The demography of, and factors that influence these metrics, are largely unknown for most vultures in the Americas. Survivorship of Turkey Vultures (Cathartes aura) may be influenced by landscape heterogeneity and human disturbance. We quantified the effects of landscape composition (Shannon’s diversity index) and configuration (contagion, edge density, and largest patch index), and human disturbance (road density) on the annual and seasonal survival probabilities of the 3 North American breeding populations (western, central, and eastern) of Turkey Vultures that spend the nonbreeding season in the southeastern portion of the Nearctic and the northern Neotropics during a 17-yr period. We used Cox’s proportional hazards models with time-varying covariates to estimate spatial and temporal changes in survival rates of adult Turkey Vultures. Road density, but not landscape composition or configuration, influenced survival rates in space and time. Overall annual survival averaged 0.87 (95% CI: 0.74–0.98). Mortality risk was low in western and central populations (hazard ratio < 1) but was 3.7 times greater for vultures in the eastern population. Survival during the breeding (0.97, 95% CI: 0.96–0.98) and outbound migration (1.0, 95% CI: 1–1) seasons was significantly higher than the other seasons. Average survival tended to be higher for nonbreeding (0.81, 95% CI: 0.71–0.88) compared to return migration (0.69, 95% CI: 0.56–0.81) seasons. Risk of mortality for all vulture populations increased with road density, and this was greater during the nonbreeding and return migration seasons. The spatial variation in road density across the Americas may generate a network of ecological traps for Turkey Vultures induced to stop in areas of greater road-kill abundance. Road killed animals acting as an attractant for vultures can increase the occurrence of vulture–vehicle collisions and potentially aggravate human–wildlife conflicts. Further analyses are needed to address survivorship and mortality factors for young birds. Our results may help to the implementation of specific mitigation efforts to reduce human–vulture conflicts and vulture mortality. For instance, concentrating efforts to remove road-killed animals in areas where road density is highest can likely reduce vulture–vehicle collisions and associated mortalities of these birds.
... Such artificial structures can also be used successfully to enhance the biodiversity of urban environments. So, the intelligent use of such structure by managing agencies can reduce the direct and indirect impacts of linear infrastructure intrusions and support and sustain the biodiversity of the area (Bissonette, 2002;Benítez-López et al., 2010). Environmental impact assessment studies that are currently not mandatory in some countries (e.g., India) should be made mandatory to facilitate such planning along the potential habitats of sensitive faunal groups before implementation of the projects and the effects should be regularly monitored during the operation phase. ...
This review examines the reported impacts of three major linear infrastructure developments, namely railways, roads and power lines on avifauna. These infrastructures are proliferating worldwide posing serious threats to wildlife including avifauna. The major impacts involved with linear infrastructures are habitat degradation, fragmentation, direct mortality by collision and electrocution. The factors affecting collision mortality can be divided into intrinsic and extrinsic factors. The intrinsic factors include species morphology and species behavior whereas the extrinsic factors are the external factors such as weather, landscape features and the technical aspects of the infrastructure. Power lines affect a large number of birds, killing more than one billion birds globally each year. Studies suggest the implementation of anti-collision devices such as wire markers; flight diverters and physical barriers like trees, diversion poles or noise barriers are effective mitigation measures to reduce bird mortality due to the linear infrastructures. Therefore, understanding the overall impact of linear infrastructures is crucial for effectively managing their impacts on avifauna and helping make future developments less destructive and more sustainable.
... Global assessments showed that urban expansion has caused about 50 % loss of local species richness, and about 38 % loss of total abundance of species in intensively used urbanised areas compared to a naturally unimpacted land (Li et al., 2022). Transport infrastructure such as roads and railways also alter ecological conditions, by cutting through natural habitats and consequently reducing populations of many wildlife species, with ecological impacts extending into the adjacent landscape from few hundred meters up to 50 km (Benítez- López et al., 2010). Impacts of urban development can also be linked to the direct transformation and alteration of ecosystem functioning (e.g. the construction of dams and weirs in rivers and lakes, port infrastructure hindering coastal drift and sediment transport, etc.), as well as to source-related impacts from upstream rural or urban terrestrial areas (e.g. ...
The world is facing a triple planetary crisis consisting of climate change, biodiversity loss, and pollution, which pose a major challenge to human health, well-being and prosperity for present and future generations. One of the main reasons for this is our current production and consumption system. Consequently, the entire production and consumption system and the entire value chain of products and services must be considered to minimise those unsustainable levels. Circular economy aims to transform our economy from the current mostly linear take-make-waste model towards a closed-loop model. In doing so, a circular economy can minimise the use of materials and energy, while reducing environmental pressures. This report therefore analyses how circular economy can contribute to halting biodiversity loss. It concludes that while circular economy measures (directly and indirectly) contribute to meeting biodiversity and climate strategic objectives, the combination with biodiversity-friendly sourcing is crucial in order to halt biodiversity loss.
... Several studies provided evidence of broad-scale impacts of human activity on animal movement, such as shortened displacements, alternated movement rates and timing, and decreased home range sizes (Doherty et al., 2021;Main et al., 2020;Tucker et al., 2018;Wyckoff et al., 2018). For ungulates, anthropogenic infrastructure such as roads, railways, and fences are well known to act as barriers (Benítez-López et al., 2010;Linnell et al., 2016;McInturff et al., 2020). The presence of infrastructure can disrupt both longdistance movements, such as in Mongolian gazelles (Procapra gutturosa; Nandintsetseg et al., 2019), Asiatic wild asses (Equus hemionus kulan; Ito et al., 2013), and mule deer (Odocoileus hemionus; Wyckoff et al., 2018), and short-distance movements, such as in elk (Prokopenko et al., 2017) and roe deer . ...
Human activity and associated landscape modifications alter the movements of animals with consequences for populations and ecosystems worldwide. Species performing long-distance movements are thought to be particularly sensitive to human impact. Despite the increasing anthropogenic pressure, it remains challenging to understand and predict animals' responses to human activity. Here we address this knowledge gap using 1206 Global Positioning System movement trajectories of 815 individuals from 14 red deer (Cervus elaphus) and 14 elk (Cervus canadensis) populations spanning wide environmental gradients, namely the latitudinal range from the Alps to Scandinavia in Europe, and the Greater Yellowstone Ecosystem in North America. We measured individual-level movements relative to the environmental context, or movement expression, using the standardized metric Intensity of Use, reflecting both the directionality and extent of movements. We expected movement expression to be affected by resource (Normalized Difference Vegetation Index, NDVI) predictability and topography, but those factors to be superseded by human impact. Red deer and elk movement expression varied along a continuum, from highly segmented trajectories over relatively small areas (high intensity of use), to directed transitions through restricted corridors (low intensity of use). Human activity (Human Footprint Index, HFI) was the strongest driver of movement expression, with a steep increase in Intensity of Use as HFI increased, but only until a threshold was reached. After exceeding this level of impact, the Intensity of Use remained unchanged. These results indicate the overall sensitivity of Cervus movement expression to human activity and suggest a limitation of plastic responses under high human pressure, despite the species also occurring in human-dominated landscapes. Our work represents the first comparison of metric-based movement expression across widely distributed populations of a deer genus, contributing to the understanding and prediction of animals' responses to human activity.
... • The reduction of road density significantly improves aquatic and terrestrial systems, decreases stressors to wildlife, and also brings jobs to local communities (39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49). The maps on pages 52 to 54 highlight the specific roads we have identified for closing or decommissioning due to ecological risk, including aquatic impact factors such as the number of stream crossings, particular topographic qualities, and erosion potential. ...
... Additionally, road networks constitute an ecological barrier to the movement of terrestrial animals, affecting the distribution and isolation of populations (Barrientos et al., 2021;van der Ree et al., 2011). Currently, evidence shows that a significant decline in biodiversity is associated with the presence and density of road networks (Benítez-López et al., 2010;Kociolek and Clevenger, 2009;Loss et al., 2014;van der Ree et al., 2011). To study the persistence of animal populations under the ecological pressures imposed by roads and traffic, a growing body of studies is accumulating on the causes of species susceptibility to road mortality. ...
We test a forecasting strategy to identify potential hotspots of amphibian roadkill, combining the spatial distribution of amphibians, their relative risk of collision with vehicles and data on road density in Spain. We extracted a large dataset from studies reporting road casualties of 39 European amphibian species and then estimated the ‘relative roadkill risk’ of species as the frequency of occurrence of casualties for each amphibian and standardized by the range of distribution of the species in Europe. Using a map with the spatial distribution of Spanish amphibians at a spatial resolution of 10 × 10 Km squares, we estimated the ‘cumulative relative risk of roadkill’ for each amphibian assemblage as the sum of risk estimates previously calculated for each species. We also calculated the total length of roads in each square (road density). Finally, combining all layers of information, we elaborated a forecasting map highlighting the potential amphibian roadkill risk across Spain. Our findings are relevant to suggest areas that should be focused on at more detailed spatial scales. Additionally, we found that the frequency of roadkill was unrelated to the evolutionary distinctiveness score and conservation status of amphibian species, while was positively correlated with their distribution range.
... Knowledge of the REZ effects for different species is critical when designing road mitigation measures. Road effect zones can differ widely for wildlife species and road types (Benítez-López et al. 2010). Larger carnivores such as grizzly bears (Ursus arctos) shift their REZ (0.2 to 0.9 km) when encountering major and minor roads (Kasworm and Manley 1990), whereas western chimpanzees (Pan troglodyes verus) have much larger REZs (major: 17.2 km; minor: 5.4 km; Andrasi et al. 2021). ...
Assessment of locations where wildlife species cross highways is a key question in mitigating future wildlife-vehicle mortality. Examination of the spatial structure, complexities, and patterns of vegetation or other land-use types (i.e., cropland, urban areas) near roadways allows scientists to identify any thresholds that influence where animals are likely to die or successfully cross the roadway. We used a historic 1982 to 2017 dataset of ocelot (Leopardus pardalis pardalis) mortality locations and approximate road crossing locations of telemetered ocelots in the Lower Rio Grande Valley in Texas to examine the spatial structure of woody vegetation within a hypothesized road effect zone. We determined if there were differences in the spatial structure of woody cover within a 1050 m buffer of each successful crossing and roadkill location using PERMANOVA and principal component analyses. We used a similarity percentages analysis to determine the relative contribution of each aspect of spatial structure on differences in successful crossing and roadkill locations. We found statistically significant differences in spatial attributes of patches at the locations of successful crossing versus roadkill locations of ocelots at the 150 m spatial extent (pseudo-F 1,41 = 4.85, P(perm) = 0.008, permutations = 9949). Largest patch index contributed most to the differences between successful crossing and roadkill locations (15.94%), followed by mean patch area (15.44%), percent woody cover (15.18%), aggregation indices (14.53%), Euclidean nearest neighbor (13.47%), edge (13.08%) and patch densities (12.36%). Roadkill locations were clustered in locations with lower-quality woody cover within 300 m of the highway. This suggests areas immediately surrounding roads need to contain woody patches that are larger and closer together to reduce the barrier-effects of roads. Such information is important for informing highway planners about where to encourage crossings or to build wildlife crossing structures to promote movement across the highway.
... The effect of disturbance associated with energy development is most significant for habitat specialists and area-sensitive species that require large expanses of intact habitat (e.g., Brittingham et al., 2014;Walker et al., 2019). Up to 75% of habitat loss associated with energy development can be attributed to supporting infrastructure such as roads, fences, and pipelines (Baynard et al., 2017;Copeland et al., 2017;Donnelly et al., 2017;Preston & Kim, 2016;Sawyer et al., 2002) resulting in biodiversity decline for multiple taxa in proximity to these features (Benítez-López et al., 2010). ...
Wildlife population dynamics are modulated by abiotic and biotic factors, typically climate, resource availability, density-dependent effects, and predator-prey interactions. Understanding whether and how human-caused disturbances shape these ecological processes is helpful for the conservation and management of wildlife and their habitats within increasingly human-dominated landscapes. However, many jurisdictions lack either long-term longitudinal data on wildlife populations or measures of the interplay between human-mediated disturbance, climate, and predator density. Here, we use a 50-year time series (1962-2012) on mule deer (Odocoileus hemionus) demographics, seasonal weather, predator density, and oil and gas development patterns from the North Dakota Badlands, USA, to investigate long-term effects of landscape-level disturbance on mule deer fawn fall recruitment, which has declined precipitously over the last number of decades. Mule deer fawn fall recruitment in this study represents the number of fawns per female (fawn:female ratio) that survive through the summer to October. We used this fawn recruitment index to evaluate the composite effects of interannual extreme weather conditions, energy development, and predator density. We found that density-dependent effects and harsh seasonal weather were the main drivers of fawn fall recruitment in the North Dakota Badlands. These effects were further shaped by the interaction between harsh seasonal weather and predator density (i.e., lower fawn fall recruitment when harsh weather was combined with higher predator density). Additionally, we found that fawn fall recruitment was modulated by interactions between seasonal weather and energy development (i.e., lower fawn fall recruitment when harsh weather was combined with higher density of active oil and gas wells). Interestingly, we found that the combined effect of predator density and energy development was not interactive but rather additive. Our analysis demonstrates how energy development may modulate fluctuations in mule deer fawn fall recruitment concurrent with biotic (density-dependency, habitat, predation, woody vegetation encroachment) and abiotic (harsh seasonal weather) drivers. Density-dependent patterns emerge, presumably due to limited quality habitat, being the primary factor influencing fall fawn recruitment in mule deer. Secondarily, stochastic weather events periodically cause dramatic declines in recruitment. And finally, the additive effects of human disturbance and predation can induce fluctuations in fawn fall recruitment. Here we make the case for using long-term datasets for setting long-term wildlife management goals that decision makers and the public can understand and support.
... Indicators for ecosystem integrity were developed following the process described in the United Nations' SEEA-EA framework ( Fig. 3; United Nations, 2021): Seven characteristics of active dune ecological processes were identified from the literature, incorporating abiotic (physical), biotic (composition, structure, function), and landscape characteristics (Table 1) and following SEEA-EA guidelines (Czúcz et al., (Bennett, 2017;Gao et al., 2020). Increasing distance from road networks reduces negative impacts on ecosystems (Bennett, 2017;Benítez-López et al., 2010). ...
Biodiversity and ecosystem functions are deteriorating worldwide, and there is an urgent need to reverse these declines and set ecosystems on a path to recovery. Effective monitoring, including a fit for purpose indicator framework, is essential to track progress towards targets but, as yet there is no universal framework that delivers timely data on biodiversity and ecosystem change. Ecosystem integrity is a unifying concept that refers to the capacity of an ecosystem to be resilient to natural or anthropogenic perturbations, and to maintain characteristic species composition, structure, functioning and self-organisation over time within a natural range of variability. Using a case study which can be generalised to international contexts, we implement and test a new global standard for the assessment, monitoring and ranking of ecosystem integrity of active sand dunes in Aotearoa New Zealand.
... Populations can also fluctuate substantially fromyear to year, especially in unstable environments (e.g., semi-deserts;Jordan et al., 2017). Finally, humans can directly (e.g.,Benítez-López et al., 2017) or indirectly (e.g.,Benítez-López et al., 2010;de Jonge et al., 2022) influence bird population densities, which in turn can cause trophic cascade effects ...
Aim: How population density varies across animal species in the context of environmental gradients, and associated migratory strategies, remains poorly understood. The recent influx of avian trait data and population density estimates allows these patterns to be described and explored in unprecedented detail. This study aims to identify the main macroecological drivers of population density in birds.
Location: Global.
Time period: 1970-2021.
Major taxa studied: Birds (Aves).
Methods: We collated a dataset of 5072 local population density estimates for 1853 species and modelled population density as a function of trait and environmental predictors in a Bayesian framework accounting for phylogenetic and spatial autocor-relation. We explored the influence of body mass, diet, primary lifestyle, mating system , nesting behaviour, territoriality, and migratory behaviour on population density, accounting for a range of environmental variables, including preferred habitat type, primary productivity, precipitation and temperature. Based on this empirical baseline, we then predicted the mean population density for 9089 species of birds and estimated global geographic patterns of bird population density. Results: Population density was lower in species with larger body mass and higher trophic levels, and also declined in territorial species, migratory species, brood parasites and species inhabiting resource-poor habitat types (e.g., deserts). Conversely, population density increased in cooperative breeders. Environmental drivers were most influential for migratory birds, with precipitation and temperature both associated with higher population density. Overall, bird population densities were higher at lower latitudes.
Main conclusions: Our results support previous findings on the role of body mass, diet and environmental gradients, but also reveal novel species-specific drivers of avian densities related to reproduction, migration and resource-holding behaviour. Substantial fine-scale variation remains unexplained. We provide a global dataset of population density predictions for use in macroecological analyses and conservation assessments.
... It is particularly preferred during times of uncertainty, to create jobs and stimulate demand. However, numerous studies have shown that infrastructure-led growth causes significant and often irreversible negative impacts on ecosystems and biodiversity conservation (Benítez-López et al. 2010;Laurance et al. 2009Laurance et al. , 2015Seto et al. 2012). Figure 1 visualizes the three cycles through which infrastructure development contributes to biodiversity loss. ...
Standing in front of perhaps the most crucial decade of the future to come, when mankind has just experienced three years of global pandemic, a raging war, extreme climate events and mass extinction of animals and plants, we have arrived at a crossroads. Decisions must be made on whether we charge at full speed to explore alternative social-ecological systems that lead to human well-being and regeneration of nature; or continue down a pathway built on resource extraction, unsustainable and unethical urbanization and destruction of nature and lives. Recently, as countries seek to recover from the pandemic, many are contemplating large-scale infrastructure schemes and projects, which have been tried and proven means to drive extraction-based economic growth. This highlights the importance of environmental justice and resistance-an area from which voices are not often heard loud enough, yet offers fertile ground where radical, sustainable alternatives may emerge among people and communities that refuse to comply with the unjust development imposed on them. Our work seeks to contribute to research studying the potential of such phenomena, by designing a framework to capture key organizational, political and ethical features that make resistance a transformative practice. The outcome of this effort is a Resistance-Based Transformative Alternative (ReBasTA) Framework, which can be employed to inform both desktop-based data collection and analysis on resistance practices, as well as in-depth field research on deep drivers and leverage points for transformation. Moreover, the framework makes longitude study of transformative practice possible, by using a consistent set of criteria. This paper introduces the conceptual and methodological approach underlying our framework and, the collaborative process employed in designing it and its key criteria. In the final section, we also discuss possible applications, with particular reference to resistance movements triggered by large-scale infrastructures.
... Both roads and railways are considered biodiversity disturbing infrastructure. The cause-and-effect relationship between infrastructure and MSA is quantified based on a meta-analysis (Benítez-López, Alkemade and Verweij, 2010), assigning the overall MSAI for the 1-km impact zone as 0.78. As GLOBIO assumes that infrastructure does not cause additional MSA loss in urban areas and cropland except for the direct effect of land use, the MSA I for urban areas and cropland is 1. ...
ABC-Map was designed with the specific objective of holistically assessing the environmental impacts of national policies, plans and investments in the agriculture, forestry and other land use (AFOLU) sector through Google Earth-based satellite imagery. ABC-Map helps to develop synergies and trade-offs between climate, biodiversity and land restoration actions.
The Adaptation section helps to understand exposure to climate change risks and to assess climate change over time in a given area. It includes a climate and geophysical profile with, for example, information on temperature and precipitation trends over the past 40 years.
The Biodiversity section covers a series of indicators that are intended to complement each other and provide a more comprehensive view of pressures and impacts on biodiversity. These indicators are average species abundance, land use change in protected areas and key biodiversity areas, and natural capital.
The Carbon section aims to account for greenhouse gas (GHG) emissions in the AFOLU sector and work towards their reduction. The Carbon section is similar to the Nationally Determined Contributions Expert Tool (NEXT), it takes into account the evolution of the carbon stock, the carbon balance and the social value of carbon.
The overall objective of this technical manual is to provide users with (i) the detailed structure of ABC-Map, (ii) its methodological background, and (iii) the different data and factors used such as emission factors and default carbon stock values, reference values from ESVD, GLOBIO, climate and geophysical datasets among others.
... The development of transportation networks and complex settlement shapes in mountainous areas has led to a stronger disorderly fragmentation of the original landscape patches, seriously impacting the cycle of regional ecological functions [92]. While rural settlement roads can extend to higher heights, steeper slopes, and more sensitive habitats than urban roads [99], the length and spatial distribution of the rural roads largely complicate the landscape and ecological impacts [29], resulting in the landscape fragmentation of woodlands and biological reserves. ...
Exploring the influence of settlement patterns on the landscape fragmentation in woodlands and biological reserves is key to achieving ecologically sustainable development. In this research, we chose the Nanshan National Park in Hunan Province, China, as a case study, to explore the influence mechanisms. First, we identified the biological reserves through the landscape security patterns of biological conservation. Second, we constructed a coupling coordination model to analyze the coupling relationship between the settlement patterns and landscape fragmentation in the woodlands and biological reserves. The analysis showed that, overall, the effect of the settlement area on the landscape fragmentation in the biological reserves was more pronounced, while the effect of the settlement spread and shape on the landscape fragmentation in the woodlands was more obvious. From a type-specific perspective, we analyzed the coupling relationship between the settlement patterns and (1) the landscape fragmentation in different woodlands and (2) the landscape fragmentation in the biological reserves, namely concerning Leiothrix lutea and Emberiza aureola. We found that the effect of the settlement patterns on the landscape fragmentation of the Leiothrix lutea biological reserve was more significant than that of the landscape fragmentation of its main habitat, the evergreen broad-leaved forest. The effect of settlement patterns on the landscape fragmentation of the Emberiza aureola biological reserve was more significant than that of the landscape fragmentation of its other habitats. In addition, the results demonstrated that the habitat protection of the woodlands was not a substitute for the systematic protection of biosecurity patterns. This research could assist in developing more efficient conservation measures for ecologically protected sites with rural settlements.
... Our results from the dbRDA analysis showed that, in addition to natural barriers like rivers, the presence of pervasive infrastructures in anthropogenic landscapes, such as roads and railways, explains a large part of genetic variance among populations, despite the short geographical distance between them. Several studies have revealed that human landscape disturbances have significant genetic effects on wild species at different temporal and spatial scales (Benítez-López et al. 2010;García et al. 2021). Because the expansion occurs when most linear infrastructures were already built, the system provides a natural experiment for studying the impact of humandriven habitat fragmentation on a species' genetic variation. ...
In the Anthropocene, many species are rapidly shifting their ranges in response to human-driven habitat modifications. Studying patterns and genetic signatures of range shifts helps to understand how species cope with environmental disturbances and predict future shifts in the face of global environmental change. We investigated the genetic signature of a contemporary wide-range expansion observed in the Iberian common vole Microtus arvalis asturianus shortly after a colonization event. We used mtDNA and microsatellite data to investigate patterns of genetic diversity, structure, demography, and gene flow across 57 localities covering the historical range of the species and the newly colonized area. The results showed a genetic footprint more compatible with a true range expansion (i.e. the colonization of previously unoccupied areas), than with a model of "colonization from within" (i.e. local expansions from small, unnoticed populations). Genetic diversity measures indicated that the source population was likely located at the NE of the historical range, with a declining gradient of genetic diversity towards the more recently invaded areas. At the expansion front, we observed the greatest gene flow and smallest pairwise differences between nearby localities. Both natural landscape features (rivers) and recent anthropogenic barriers (roads, railways) explained a large proportion of genetic variance among populations and had a significant impact on the colonization pathways used by voles.
... The last row indicates the total number of admissions for each animal group. abundance (Klem, 1989;Fahrig & Rytwinski, 2009;Klem et al., 2009;Benítez-López et al., 2010;Loss et al., 2014;Loss et al., 2015;Aymí et al., 2017). We found that there is a wide range of taxa (61 species from 38 families) that were injured due to road accidents with less than one quarter of these animals (23 %) which are eventually released. ...
The ultimate goal of Wildlife Rehabilitation Centres is to release wild animals back into the wild, after providing care and treatment according to protocol. The data collected during the process though, can be an invaluable resource of information, and act as a proxy of the anthropogenic impact on wild populations. They can even help to propose mitigation and conservation measures that could reduce pressure on wildlife. In the current study, we analysed the records of ANIMA, a prominent Wildlife Rehabilitation Centre in Athens, Greece, over a 17-year study period. Using a database of 54,445 animals representing 353 species from 104 families, we draw connections between the magnitude of admission causes and their predicted outcomes based on the animals admitted. We found that while many animals that are admitted as orphans or after living in captivity have good chances of being released, that is not the case for victims of electrocution or domestic animal attacks. Illegal shooting is clearly present in our data and seems to also affect wild populations negatively. We highlight the importance of Wildlife Rehabilitation Centres’ data towards understanding and defining human impact on wildlife, the importance of communicating the results to policymakers for biodiversity conservation and even proposing possible management directions. In that context, we also urge for more population monitoring field studies, so that admission data can be accurately combined and make meaningful predictions for the status of wild populations. Full text available at: https://authors.elsevier.com/a/1gkm45liTFNyfm
Jaringan jalan dan penggunaan lahan di sekitarnya menciptakan lanskap dengan struktur, komposisi, konfigurasi, dan interaksi tertentu yang berpengaruh terhadap proses-proses ekologis bagi keberadaan dan sebaran satwa burung. Membandingkan kekayaan jenis burung pada areal-areal yang demikian akan memberikan pemahaman yang lebih baik tentang bagaimana jaringan jalan dan penggunaan lahan dalam suatu lanskap berpengaruh terhadap sebaran kekayaan jenis burung. Tujuan penelitian adalah untuk mengetahui perbedaan kekayaan jenis burung pada berbagai kelompok jarak pengamatan di sekitar ruas jalan Negeri Lima – Laha. Uji korelasi dan uji analisis varians (ANOVA) satu arah digunakan untuk mengetahui karakteristik hubungan serta perbedaan rerata kekayaan jenis burung dari setiap kelompok jarak pengamatan dari ruas jalan. Kekayaan jenis burung yang ditemukan di lokasi penelitian sebanyak 38 spesies dengan 32 spesies burung diantaranya dapat diidentifikasi dan 6 spesies lainnya belum teridentifikasi. Kekayaan jenis burung pada masing-masing kelompok jarak pengamatan dari ruas jalan menunjukkan tren penurunan kekayaan jenis seiring bertambahnya jarak pengamatan dari ruas jalan. Hasil uji korelasi didapatkan nilai koefisien korelasi (r) = -0,69 dengan Pvalue (0,001) < α (0,05), yang menunjukkan adanya korelasi negatif moderat dan signifikan antara variabel kekayaan jenis burung dengan variabel jarak pengamatan dari ruas jalan. Hasil uji ANOVA dari rerata hitung kekayaan jenis burung di antara kelompok-kelompok jarak menghasilkan nilai Pvalue (0.04) < α (0.05), dengan demikian H0 ditolak, yang berarti bahwa terdapat perbedaan yang nyata dari rerata hitung kekayaan jenis burung di antara kelompok jarak pengamatan dari ruas jalan di lokasi penelitian.
Transportation infrastructure is one of the biggest concerns for biodiversity worldwide. Roads affect ecological processes by creating barriers to animal movement, causing habitat loss and fragmentation, and increasing pollution and habitat degradation by promoting human access to new areas. For many species, mortality due to collision with vehicles can lead to a drastic reduction in population size and change the population dynamics. These changes may also cause a reduction in population viability and increase the risk of local extinctions. In this scenario, the researchers have been focused primarily on understanding how mortality and barriers affect wildlife populations to propose mitigation measures to maintain long-term viable populations. The use of molecular tools has been a great advance to quantify the impacts of roads on populations and to estimate its extinction risk. In this chapter, our main goal is to provide the state-of-the-art on the impacts of roads on wildlife populations. We show how molecular analysis can be a valuable tool to evaluate the effects of roads on wildlife and to what extent it has been used in the Neotropics. Furthermore, this chapter opens up an important research frontier for biologists and ecologists by highlighting the current and future challenges of research in molecular road ecology.KeywordsBarrier effectsLandscape geneticsMolecular ecologyVertebrate roadkill
Pollinating insects provide vital ecosystem services and are facing global declines and habitat loss. Roadsides are increasingly regarded as important potential areas for enhancing pollinator habitat. Understanding which roadsides best support pollinators—and why—is essential to helping locate and prioritize pollinator conservation efforts across roadside networks. To support this effort, we assessed butterfly, bee, and flowering plant species richness and abundance on a set of 63 stratified randomized roadside transects in State-managed rights-of-way in SE Idaho. Our research evaluated pollinator diversity as a function of highway class (interstate, U.S., and state highways), remotely sensed NDVI values (a measure of vegetation greenness), and floral resources. We found that smaller highways and lower (less green) maximum NDVI values were associated with significantly more bee species and total bees. Roadsides bordering sagebrush habitats typically had low NDVI values and higher bee and butterfly species richness, potentially contributing to this observed pattern. Butterfly richness increased in association with higher floral abundance in roadsides. Additionally, we identified and mapped 1,363 roadside patches of milkweed (Asclepias speciosa), larval host plant for the imperiled monarch butterfly (Danaus plexippus), in a survey of over 900 miles of southern Idaho highways. Based on these results and a literature review, we recommend management strategies to promote the health of pollinator populations in Idaho’s rights-of-way and provide data to help ITD prioritize areas for pollinator-friendly management practices and habitat restoration within their highway system.
Immer mehr Windenergieanlagen (WEA) werden in Deutschland in Wirtschaftswäldern errichtet. Bisher ist wenig darüber bekannt, ob WEA in Wäldern häufige Vögel verdrängen, deren Schutz beim Bau von WEA geringe Priorität hat. Um diese Wissenslücke zu füllen, haben wir mittels Punkt-Stopp-Zählungen Singvögel in unterschiedlichen Distanzen zu WEA in 24 Wirtschaftswäldern in Hessen erfasst. Unsere Ergebnisse zeigen, dass Vogelgemeinschaften in Wirtschaftswäldern stark mit der Qualität des Waldes, der Jahreszeit und dem Rotordurchmesser der WEA zusammenhingen, nicht aber mit der Entfernung zur WEA. Beispielsweise war die Anzahl von Vögeln in strukturarmen gegenüber strukturreichen Wäldern um 38 %, in Monokulturen gegenüber Mischkulturen um 41 %, in jungen gegenüber alten Laubwäldern um 36 % und in Wäldern mit großen statt kleinen WEA um 24 % verringert. Unsere Ergebnisse deuten darauf hin, dass WEA in Wirtschaftswäldern häufige Vögel verdrängen. Allerdings reagierten Vogelgemeinschaften empfindlicher auf lokale Unterschiede in der Qualität von Wäldern als auf Einflüsse der WEA. Um eine weitere Verdrängung von Vögeln zu verhindern, sollten strukturarme Wirtschaftswälder mit niedriger Habitatqualität als Standorte für WEA bevorzugt werden.
Comprehending the population trend and understanding the distribution range dynamics of species are necessary for global species protection. Recognizing what causes dynamic distribution change is crucial for identifying species' environmental preferences and formulating protection policies. Here, we studied the rear-edge population of the flagship species, giant pandas (Ailuropoda melanoleuca), to (1) assess their population trend using their distribution patterns, (2) evaluate their distribution dynamics change from the second (1988) to the third (2001) survey (2-3 Interval) and third to the fourth (2013) survey (3-4 Interval) using a machine learning algorithm (eXtremely Gradient Boosting), and (3) decode model results to identify driver factors in the first known use of SHapley Additive exPlanations. Our results showed that the population trends in Liangshan Mountains were worst in the second survey (k = 1.050), improved by the third survey (k = 0.97), but deteriorated by the fourth survey (k = 0.996), which indicates a worrying population future. We found that precipitation had the most significant influence on distribution dynamics among several potential environmental factors, showing a negative correlation between precipitation and giant panda expansion. We recommend that further research is needed to understand the microenvironment and animal distribution dynamics. We provide a fresh perspective on the dynamics of giant panda distribution, highlighting novel focal points for ecological research on this species. Our study offers theoretical underpinnings that could inform the formulation of more effective conservation policies. Also, we emphasize the uniqueness and importance of the Liangshan Mountains giant pandas as the rear-edge population, which is at a high risk of population extinction.
Collisions between trains and moose that cross a track are common occurrences according to rail accident statistics. A moose lying on a track after a crash may increase the risk of train derailment. In addition, a moose thrown into the air during a collision may also hit and damage the pantograph, which prevents a train from running. This paper developed a finite element (FE) model of moose and is aimed at investigating the train crash safety and moose motion trajectory in train-moose collisions for different moose crossing scenarios using the FE method. Material biomechanics tests were conducted to obtain the mechanical property parameters of moose. Drop hammer impact tests were performed to validate the constitutive models of different moose segments. The whole moose FE model was verified against previous vehicle-moose crash tests. The numerical impact scenes of moose crossing the rail at different collision positions were established in LS-DYNA. The results showed that the impact force depends on the contact area between the train and the moose. A larger contact area corresponded to a larger impact force. The moose would be pushed away by the V-shaped locomotive and would not cause a derailment, and the height of the moose thrown into the air cannot reach the height of the pantograph, which would prevent damage to the pantograph of a bullet train.
Linear infrastructure (LI) has varying effects on landscapes depending on different ecosystems' sensitivity and threat levels. Economically developing tropical countries are particularly at risk from LI. Therefore, understanding a country's current LI network and planning future developments to avoid further fragmentation and disturbance is crucial. This study aimed to assess the extent of Sri Lanka's LI network (i.e., roads, railroads, and powerlines), given that it is both a biodiversity hotspot and an economically developing country in the tropics. First, we calculated the average Normalized Difference Vegetation Index (NDVI) and Normalized Difference Built-up Index (NDBI) indices and examined their spatial autocorrelation per divisional secretariat division. Then a multivariate cluster analysis was used to determine clusters of natural and protected areas that may receive similar impacts from different LI and their combinations. Results indicated that roads are the most widespread LI type in Sri Lanka, followed by transmission lines and railroads. Over 80% of Sri Lanka's total land area falls within 1 km of either a national or a provincial/local road. Areas with high NDVI were primarily manmade habitats, with less than 20% contribution from protected areas. Over 50% of the total protected area of Sri Lanka is being impacted by all three types of LI. Powerlines were the most common LI type in protected areas in proportion to their total lengths. To minimize environmental impact while achieving development goals, future LI development activities should use a landscape approach to identify development needs and strategies informed by these findings.
Current climate and land cover change threaten global mountaintops with increased spread of invasive species. Long-established plantations of invasive trees on these mountaintops can alter their surroundings, further increasing invader-facilitated invasion. Identifying the ecological conditions promoting such associations can help develop better management interventions. The Western Ghats's Shola Sky Islands (>1400 m MSL) host vast stretches of invasive tree plantations that sustain the colonization of other invasive woody, herbaceous, and fern species in their understories. Here, we analyzed vegetation and landscape variables from 232 systematically placed plots in randomly selected grids using non-metric multidimensional scaling and Phi coefficient approaches to examine patterns of association (positive interactions) between understory invasive species with specific invasive overstory species. We also conducted GLMM with zero inflation to determine the influence of environmental variables where such associations occur. We find that understory invasion of multiple species under the canopy of other invasives is widespread across the Shola Sky Islands. Stands of Eucalyptus host the colonization of 70% of non-native invasive species surveyed across the Shola Sky Islands. In particular, the Lantana camara invasion is strongly associated with Eucalyptus stands. We also found that climatic variables affect the colonization of understory woody invasive species, while invasion by exotic herbaceous species is associated with the density of road networks. Canopy cover impacts all invasives negatively, while fire incidence was negatively associated with invasion by Lantana spp. and the Pteridium spp. While the restoration of natural habitats primarily targets the highly invasive Acacia, less invasive Eucalyptus and Pinus are often not included. Our study suggests that retaining such invasive species in natural habitats, particularly protected areas, can hinder ongoing grassland restoration efforts by facilitating further invasions by multiple woody and herbaceous species.
Anthropogenic noise is ubiquitous across environments and can have negative effects on animals, ranging from physiology to community structure. Recent work with captive-bred zebra finches demonstrated that traffic noise also affects cognitive performance. We examined whether these results extend to animals that have experienced noise in the wild. We collected black-capped chickadees from areas frequently exposed to road traffic noise and tested them on a detour reaching task, a commonly used measure of inhibitory control. Those chickadees exposed to traffic noise playback had much lower performance on the task than control birds, indicating that noise negatively impacts inhibitory control. These data corroborate previous findings in lab-reared zebra finches. Furthermore, these results suggest that prior experience with traffic noise is not sufficient for animals to habituate to noise and overcome its negative effects on cognitive performance. Instead, noise-induced cognitive effects might have broad impacts on animal species living in noise-polluted habitats.
Due to rapid human expansion in the last century, wildlife roadkill is becoming a concerning threat to biodiversity and human safety. The frequency of roadkill events depends on factors related to specific traits of the road—tortuosity or the presence of fences, among others—and the animal ecology—such as activity patterns, reproductive season, or thermoregulation. These, in turn, are related to environmental factors, with seasonal variations. Here, we assessed roadkill mortality of terrestrial vertebrates over the year. To do this, we sampled 10 road sections (of 3 km, by walk) in the south of Spain for a full year, registering the carcasses of run-over vertebrates. Then, we analysed the spatiotemporal patterns of roadkill events for the four vertebrates’ classes and the effects of road traits (presence of fence, tortuosity, distance to water point) and environmental variables (mean temperature and precipitation). Mammals suffered the highest mortality by roadkill (45.72%). The frequency of collisions was independent of tortuosity, presence of fences, and precipitation, while mean temperature significantly increased the probability of collision of mammals, birds, and reptiles. There was a seasonal effect in the number of collisions, which spatial pattern depended on the class of vertebrates. All this leads us to conclude that, to reduce the impact caused by roadkill mortality on wildlife, we need specific measures to be taken timely in each critical place and for each vertebrate group.
Habitat fragmentation and habitat loss are two of the largest threats to biodiversity in the modern age. Because of this, the study of how animals move between patches of fragmented habitats is crucial to being able to plan for the protection and conservation of species and habitats. I conducted a functional connectivity analysis of barriers to movement for three species with different movement types and habitat requirements- northern flying squirrel (Glaucomys sabrinus), pickerel frog (Lithobates palustris), and smooth green snake (Opheodrys vernalis) - in four different regions across the eastern Canadian province of Prince Edward Island, which has seen a significant reduction in natural areas since the 19th century. Resistance maps were created for each species using critical habitat components and the open-source toolbox Linkage Mapper was used to find the least-cost
paths, barriers, and pinchpoints between core habitat areas in each region. I used the Linkage Pathways tool to find least-cost pathways between core habitat areas, Barrier Mapper tool to find areas where restoration could occur, and Pinchpoint Mapper tool to locate where movement could occur between core habitat areas outside of the least-cost path. I also compared this functional connectivity analysis to previous structural methods used on the island. I found that the cost-weighted distance and effective resistance for movement for the species varied by study region, and that O. vernalis was the least aligned with structural connectivity flow outputs. This analysis can assist landscape planners and environmental managers in making future conservation decisions.
There are great disparities in the quantity and quality of transport infrastructure. Differences in access to investment are 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’. This evidence and gap map identifies, maps and describes existing evidence on the effects of transport sector interventions related to all means of transport (roads, paths, cycle lanes, bridges, railways, ports, shipping, and inland waterways, and air transport). Suggested citation: Malhotra, S, White, H, de la Cruz, N, Saran, A, Eyers, J, John, D, Beveridge, E, Blondal, N 2021, Evidence and gap map-studies of the effectiveness of transport sector intervention in low and middle – income countries CEDIL/Campbell Gap Map 2021. Available at https://doi.org/10.51744/CSWP3
Land management priorities and decisions may result in population declines for non-target wildlife species. In the western United States, large-scale removal of conifer from sagebrush ecosystems (Artemisia spp.) is occurring to recover greater sage-grouse (Centrocercus urophasianus) populations and may result in pinyon jay (Gymnorhinus cyanocephalus) habitat loss. Jay populations have experienced long-term declines, due to unknown causes, resulting in a recent petition for listing under the Endangered Species Act of 1973. We developed a Bayesian hierarchical model of jay abundance, using 13 years of point count data (2008-2020) collected across the western United States, to estimate regional population trends, model habitat requirements, assess conifer removal effects on jays, and generate hypotheses regarding jay population declines. Our model included climate and landcover covariates and regional trends in pinyon jay density. We applied our modeled habitat relationships to map predicted pinyon jay density, given 2008 and 2020 resource conditions, and map density changes from 2008 to 2020. Our results indicate pinyon jay populations are declining within Bird Conservation Region 16. Jay density was positively associated with sagebrush cover, Palmer Drought Severity Index, and pinyon-juniper cover. Conversely, jay populations were negatively associated with Normalized Difference Vegetation Index (NDVI). We found higher pinyon jay densities within locations possessing both sagebrush and pinyon-juniper cover; conditions characteristic of phase I and II conifer encroachment which are preferentially targeted for conifer removal to restore sagebrush communities. Conifer removal, if conducted at locations with high pinyon jay densities, is therefore likely to negatively affect jay abundance.
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.
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.
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.
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.
Distribution and activity of white-tailed deer (Odocoileus virginianus) were studied on a 12.9-km sector of Interstate Highway 80 in a forested region of central Pennsylvania from May 1968 to May 1969 and on a 12.4-km agricultural section of the highway from April 1968 to May 1969. Observations of deer were made from a vehicle equipped with a spotlight for nighttime observing. Over 6,500 deer were observed and categorized as to location, behavior, sex, and age. Numbers of deer seen were related to time of day, topography, vegetation, traffic, and meteorological factors. Most of the deer seen in the forested area were grazing on the highway rights-of-way; most of those seen in the agricultural area were grazing in fields and rarely were seen on the rights-of-way. Deer tended to move into our study areas at dawn. Neither traffic volume nor weather correlated strongly with numbers of deer seen; spring and fall were times of great deer abundance in both study areas, but vegetation type and topography were more important factors in the forested area than in the agricultural area. Feeding behavior of deer in both areas dominated all other activities. The impact of the highway itself on deer abundance and distribution and the relationship between deer activity and deer-automobile collisions are functions of highway location relative to deer requisites such as feeding and resting sites and to relative availability of feeding areas other than rights-of-way.
Rapid encroachment on woodland caribou (Rangifer tarandus caribou) habitat by resource extraction industries (oil, gas, forestry, and peat) is occurring throughout northern Alberta, Canada. The effect of this human development on the movement and distribution of threatened woodland caribou remains poorly understood. We captured and fitted 36 woodland caribou with Global Positioning System (GPS) collars. These yielded 43,415 locations during the 12-month study period. We tested the hypothesis that woodland caribou use areas adjacent to wellsites, roads, and seismic lines as often as they use areas away from these developments. We analyzed caribou locations, controlling for vegetation cover classes to remove confounding effects of habitat, and grouped to examine seasonal variation in distribution. Caribou avoided human developments; the level of avoidance appeared to be related to the level of human activity in the study area. We recorded maximum avoidance distances of 1,000 m (wells) and 250 m (roads and seismic lines). By extrapolating avoidance distances to the entire study area, we calculated that 22-48% of our study area would receive reduced use by caribou. Avoidance effects were highest during late winter and calving and lowest during summer, possibly as a result of lower traffic levels then. We propose management strategies to balance caribou conservation with resource extraction in northern Alberta.
We investigated possible avoidance behavior of calving semi-domesticated reindeer (Rangifer tarandus tarandus) near recreational cabins, roads, and power transmission lines in Repparfjord Valley, northern Norway. The distribution, sex, and general age composition of the reindeer were mapped during the 1998 and 1999 calving seasons (n = 776 and n = 678, respectively) using systematic snowmobile and ski surveys. Mean reindeer density within preferred habitat was 78% lower in the area <4 km from the tourist resort compared to the area >4 km from the resort (1.47 vs. 6.68 reindeer/km2, respectively). Mean reindeer density by the power line corridor without traffic was 73% lower in the area <4 km from the power line compared to areas >4 km from the power line for comparable habitat. Areas <4 km from anthropogenic structures were avoided despite low levels of human traffic and a high proportion of preferred habitat. Within snow-free sites available for grazing, no significant differences occurred in phenological development of cotton-grass (Eriophorum spp.), in live:dead ratio of plant material, or in graminoid biomass with distance to the tourist resort. Almost 74% of all available forage was located within the avoided 0-4-km zones from the resort or the separate power line. Our results suggest that power lines, even without human traffic, may result in substantial reductions in the use of foraging areas. The combined actions of power lines, roads, and cabins may increase potential avoidance, thereby increasing the use of remaining undisturbed grazing grounds. Possible increased competition for high-quality forage may affect lactation, body condition, and, hence, reproductive success in the long term.
Park managers are concerned that moose (Alces alces), caribou (Rangifer tarandus), and grizzly bears (Ursus arctos) may be avoiding areas along the 130 km road through Denali National Park as a result of high traffic volume, thus decreasing opportunities for visitors to view wildlife. A wildlife monitoring system was developed in 1996 that used 19 landscape level viewsheds, stratified into four sections based on decreasing traffic along the road corridor. Data were collected from 22 samplings of all viewsheds during May-August in 1996 and 1997. In 1997, nine backcountry viewsheds were established in three different areas to determine whether density estimates for each species in the backcountry were higher than those for the same animals in similar road-corridor areas. Densities higher than those in the road corridor were found in one backcountry area for moose and in two backcountry areas for grizzly bears. None of the backcountry areas showed a higher density of caribou. We tested hypotheses that moose, caribou, and grizzly bear distributions were unrelated to the road and traffic. Moose sightings were lower than expected within 300 m of the road. More caribou and grizzly bears than expected occurred between 601 and 900 m from the road, while more moose and fewer caribou than expected occurred between 900 and 1200 m from the road. Bull moose in stratum 1 were distributed farther from the road than bulls and cows in stratum 4; cows in stratum 1 and bulls in stratum 2 were distributed farther from the road than cows in stratum 4. Grizzly bears in stratum 2 were distributed farther from the road than bears in stratum 3. The distribution of moose sightings suggests traffic avoidance, but the spatial pattern of preferred forage may have had more of an influence. Caribou and grizzly bear distributions indicated no pattern of traffic avoidance.