Article

Do spider monkeys use artificial canopy bridges to cross linear infrastructure?

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Deforestation impacts canopy connectivity when landscapes are fragmented due to roads and other types of linear infrastructure. Natural canopy bridges become vital to arboreal animals, especially for animals that are reluctant to use the ground. When canopy regrowth cannot occur, artificial canopy bridges have been implemented to mitigate the consequences of linear infrastructure. The aim of our study was to evaluate the evidence for the use of artificial canopy bridges by spider monkeys (Ateles spp.) to cross linear infrastructure that interrupts canopy connectivity. We report details of five cases in which the absence of evidence for spider monkeys using artificial canopy bridges to cross linear infrastructure was based on systematic monitoring. We examined the factors that may constrain spider monkeys to use artificial faunal overpasses and made recommendations for effective artificial faunal overpasses for spider monkeys.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... of the bridge, which was made of a naturally occurring liana growing on one side of the road. Other species can take several weeks (Das et al., 2009;Birot et al., 2020) or never use them at all (Aureli et al., 2022). Chan and colleagues (2020) observed that Hainan gibbons used rope bridges after 176 days. ...
... Chan and colleagues (2020) observed that Hainan gibbons used rope bridges after 176 days. A group of spider monkeys, a primate species with a very similar locomotor patterns to gibbons, did not use artificial bridges to cross over roads in a recent study (Aureli et al., 2022). Although the reasons behind this reluctance to use the bridges are not fully understood, authors suggest that the lack of vegetation layer under the bridges could be the key to explain it. ...
Article
Gibbons (Hylobatidae) are species highly adapted to tree-top living. Thus, their movement can be compromised due to the negative impact roads have on canopy habitats. In this study, we built two single-rope artificial canopy bridges and a ladder bridge at two out of five locations where a group of white-handed gibbons ( Hylobates lar ) in Khao Yai National Park, Thailand were known to cross a main park road. We compared road crossing frequencies, home-range characteristics, and other ad libitum observations during the periods before and after bridge installation. After bridge construction was complete, the group took 10 weeks to use the single rope bridges to navigate over the road. During 442 group follow observation hours and 539 bridge observation hours, 131 crosses over the road were observed. The adult female usually crossed the road first, and the group showed a clear preference for the single-rope bridges over the ladder bridge (92 crossings versus 5). Gibbons crossed the road approximately once a day and crossed mostly at the bridge locations both before and after bridge construction. There were not significant changes in crossing rates from before (crossing between the tree branches and on the ground) to after bridge installation at both the places where bridges were installed (crossing using the bridges). Nonetheless, with more crossings being in the bridges than on the ground after bridge installation, crossings were presumably safer. These findings suggest that gibbons will cross a road on the ground, risking predation, encountering people, or being hit by a vehicle, but artificial canopy bridges provided a safer crossing option since gibbons no longer crossed on the road or jumped across wide gaps at the two locations where bridges were constructed. Maintaining canopy connectivity over roads using artificial bridges logically improves home range connectivity, potentially gene flow, and safety of canopy dwellers. However, connecting areas which were not previously connected should be considered carefully. The new connection could disrupt group dynamics, particularly for species that defend territories, such as gibbons.
... However, there is not enough evidence to predict species use of a particular bridge design or even predict species use of canopy bridges in general. There are hints that smaller species may cross more frequently than larger species on bridges (Martín, 2012;Aureli et al., 2022;Flatt et al., 2022) but these studies do not compare crossing frequency to population size. ...
... For example, the colobus hand does not have a thumb, the typical morphology of the African colobines (Davies and Oates, 1994), which with their larger body size, may contribute to greater instability on the bridges resulting in a lower crossing rate than otherwise would be expected. Interestingly, but perhaps coincidentally, the spider monkey (Ateles spp.), a genus also lacking a thumb, has not been observed to use bridges (Aureli et al., 2022). ...
Article
Full-text available
For primates, canopy bridges can reduce the road barrier effect. Yet little information exists to predict species bridge use. We examined bridge use across a 9 km suburban road in Diani, Kenya, in three survey years (N bridges : 21 = 2004, 27 = 2011, 29 = 2020) by four sympatric species of monkeys. The asphalt road is 6 m wide with a 50 km/h speed limit. Roadside observers recorded ground (N = 4931) and bridge (N = 3413) crossings, crossing direction, and traffic volume. Colobus (Colobus angolensis palliatus), Sykes' monkeys (Cercopithecus mitis albogularis), and vervets (Chlorocebus pygerythrus hilgerti) used the bridges while baboons (Papio cynocephalus cynocephalus) rarely did. Crossing rates (Sykes'>vervet>colobus>baboon) did not fit our predictions based on species' attributes of stratum preference (arboreal>terrestrial) or body mass (small>large), while the interaction between these attributes was more informative. Crossings were bidirectional. Colobus crossed bridges during higher traffic volumes than on the ground, whereas we found the opposite for vervets. Sykes' monkeys crossed at similar traffic volumes on the ground and bridges. The mean annual bridge cost was USD 157, deriving a cost per crossing as < USD 0.10, though it undervalues the savings in ecosystem services, tourism benefits, and contributions to protecting colobus, a vulnerable species. While we consider this highly economical, funders and road engineers will ultimately determine if it is so.
... There is great difficulty in measuring the barrier effect of roads and railways on arboreal species, especially primates and other strictly arboreal species that use very high forest canopies (e.g., spider monkeys (Ateles spp.), Aureli et al., 2022). As these animals are rarely recorded being roadkilled on highways/railways, both public opinion and environmental and transport agencies do not see the need to install mitigation such as canopy bridges. ...
Article
Brazil is known as a high biodiversity country, but at the same time, it has an extensive road network that threatens its wildlife and ecosystems. The impacts of roads and railways on vertebrates have been documented extensively, and the discussion concerning the implementation of mitigation measures for terrestrial wildlife has increased in the last decade. Arboreal animals are especially affected by the direct loss of individuals due to animal-vehicle collisions and by the barrier effect, because most arboreal species, especially the strictly arboreal ones, avoid going down to the ground to move across the landscape. Here we summarize and review information on existing canopy bridges across Brazil, considering artificial and natural canopy bridge initiatives implemented mainly on road and railway projects. A total of 151 canopy bridges were identified across the country, 112 of which are human-made structures of different materials, while the remaining 39 are natural canopy bridges. We found canopy bridges in three of the six biomes, with higher numbers in the Atlantic Forest and Amazon, the most forested biomes. Most of the canopy bridges are in protected areas (76%) and primates are the most common target taxa for canopy bridge implementation. Our study is the first biogeographic mapping and review of canopy bridges for arboreal wildlife conservation in a megadiverse country. We synthesize the available knowledge concerning canopy bridges in Brazil and highlight gaps that should be addressed by future research and monitoring projects.
... In addition, there is evidence that some species are entirely averse to using bridges. A survey by Aureli et al. (2022) sent to 1500 researchers, produced 34 responses and no records of spider monkeys using bridges to cross over linear infrastructure. Furthermore, habituation time for bridges is often unknown but can be lengthy and seems to vary by species (e.g., Lokschin et al., 2007;Mass et al., 2011;Balbuena et al., 2019;Monticelli et al., 2022;Saralamba et al., 2022). ...
Article
Full-text available
Canopy bridges are an increasingly popular method to mitigate linear infrastructure fragmentation impacts, but little is known about when, over the course of the day and night, they are used. Natural canopy bridges monitored with camera traps provide an excellent source of information on community-wide arboreal mammal activity patterns, which are otherwise challenging to document. Natural bridges represent a hotspot of activity, being bottleneck crossing points over linear infrastructure, and cameras provide 24-hour monitoring capability. We monitored 20 natural canopy bridges over pipeline clearings distributed at two sites in the Peruvian Amazon for over a year using camera traps. Across 11 492 camera trap nights, we recorded 5165 events of 27 arboreal mammal species and used these events to describe both overall mammal activity in natural canopy bridges and activity patterns for the most frequently registered species: Aotus nigriceps, Potos flavus, Bassaricyon alleni, Caluromys lanatus, Coendou ichillus, and Sapajus apella. The long duration of our study allowed us to investigate potential changes in activity patterns resulting from seasonality and disturbance associated with pipeline construction, and the inclusion of two study sites allowed comparisons between them. We found substantially more mammalian activity in bridges during the night (87.4%) than the day, with only one of the most frequently registered species being diurnal (S. apella). Changes in activity between disturbance phases and seasons were only apparent for C. ichillus, and comparisons across species revealed differences in activity peaks, such as a unique peak early in the night for A. nigriceps. Our data provide some of the first substantial activity information for the species evaluated and help elucidate temporal patterns of canopy bridge usage to be expected for arboreal Neotropical wildlife. Knowing when to expect bridge use helps both guide the design of mitigation plans for future projects that include natural and artificial canopy bridges and identify the best monitoring methods. Given the high rate of nocturnal activity we observed, we recommend mitigation plans consider limiting human activity on linear infrastructure at night, if possible, and consider the requirements of nocturnal species in bridge designs. We also recommend camera trapping for monitoring.
Article
Full-text available
In March 2021, as the COVID-19 pandemic raged, two of us decided to organise a virtual symposium on canopy bridges for the American Society of Primatology and Smithsonian's Earth Optimism initiative. Afterall, canopy bridges are a conservation solution that invites optimism in the face of all the challenges confronting the natural world. We were astounded by the response to the symposium-we received 540 registration requests from 53 countries, and the seminar itself was a major success, with 130 live attendees (see link to recording on the ASP website: https://www.asp.org/asp-conservation/ conservation-videos/). Following that experience , we could tell that interest in the topic of canopy bridges was growing, and we therefore invited our seminar speakers and others-together representing research on five continents to join us in developing a special issue on the topic for Folia Primatologica. We had the sense that there were many studies waiting to be written, given the discrepancy between the number of studies we had heard of and the number of publications in the scientific literature. At the time of this writing, there were only 32 peer reviewed papers on bridges worldwide, with another 15 in the grey literature. Once again, we were surprised and excited to have a whopping 33 research teams submit proposals for special issue submissions, with 23 of them submitting and finally publishing their full manuscripts in this issue. These 23 additions represent research from 14 countries and five continents and a 72% increase in the number of peer reviewed publications on this topic (fig. 1). Each canopy bridge project and practitioner has a contribution to make on this relatively unknown and increasingly important topic. Given that many canopy bridge projects are grassroots initiatives, they are often run by practitioners with little publishing experience or motivation to publish-another reason we wanted to provide the opportunity to publish in a special issue. We were very pleased to see that
Article
Although artificial crossing structures are increasingly implemented by conservationists and wildlife managers to connect fragmented wildlife habitat, the study of artificial crossing structure design, particularly of canopy bridges, is an emerging field of study in primatology. We address this issue by evaluating five competing bridge models with varying width, material stiffness, and substrate spacing. We assessed bridge preference and performance by sampling the behavior of three species of Costa Rican monkeys ( Alouatta palliata : n = 4, Ateles geoffroyi : n = 3, Cebus imitator : n = 3). In a semi-wild setting, we used focal individual sampling with instantaneous recording once every minute for ten-minute intervals and all occurrences sampling whenever study subjects used the bridge. We hypothesized that monkeys prefer bridges that are more stable, and that are made of materials that resemble tree branches. During nearly 37 sampling hours we observed 119 crossing events. We found that study subjects prefer bridge models that are built using more rigid materials, such as the bamboo pole bridge, or wider bridges that offer more stability than narrower bridges. The bridge type and the materials used to build the bridges are both significant predictors of bridge use. While preference for bridges and their performance varies by species, the bamboo pole bridge model and the horizontal mesh bridge were preferred and performed best in our study. The simple liana bridge model was the least preferred by all species and performed poorly in comparison to the other models. Our findings will help us better understand how design and materials impact the use of canopy bridges by monkeys, which can help improve biological corridors and offer new information for the management and conservation of primates living near infrastructure corridors and other kinds of dangerous matrix.
Article
Although artificial crossing structures are increasingly implemented by conservationists and wildlife managers to connect fragmented wildlife habitat, the study of artificial crossing structure design, particularly of canopy bridges, is an emerging field of study in primatology.We address this issue by evaluating five competing bridge models with varying width, material stiffness, and substrate spacing. We assessed bridge preference and performance by sampling the behavior of three species of Costa Rican monkeys (Alouatta palliata: n = 4, Ateles geoffroyi: n = 3, Cebus imitator: n = 3). In a semi-wild setting, we used focal individual sampling with instantaneous recording once every minute for ten-minute intervals and all occurrences sampling whenever study subjects used the bridge. We hypothesized that monkeys prefer bridges that are more stable, and that are made of materials that resemble tree branches. During nearly 37 sampling hours we observed 119 crossing events. We found that study subjects prefer bridge models that are built using more rigid materials, such as the bamboo pole bridge, or wider bridges that offer more stability than narrower bridges. The bridge type and the materials used to build the bridges are both significant predictors of bridge use. While preference for bridges and their performance varies by species, the bamboo pole bridge model and the horizontal mesh bridge were preferred and performed best in our study. The simple liana bridge model was the least preferred by all species and performed poorly in comparison to the other models. Our findings will help us better understand how design and materials impact the use of canopy bridges by monkeys, which can help improve biological corridors and offer new information for the management and conservation of primates living near infrastructure corridors and other kinds of dangerous matrix.
Article
This paper reports the social-cultural findings from building an artificial canopy bridge for mantled howler monkeys ( Alouatta palliata ) and other arboreal mammals in Puerto Viejo, Costa Rica. We analyzed participatory observation results from participatory designing and building, and camera trap data from monitoring the bridge. This article also discusses how local perceptions towards monkeys, regional developments, and bridge functions inform primate conservation in that region. It examines a broader primate conservation strategy that addresses entangled values and bridge design in a human-centered, peri-urban, and coastal evergreen forest. We found that artificial canopy bridge design is a complex problem related to humans and targeted species. Connecting habitat with artificial canopy bridges in this context is part of a more significant urban planning problem. Bridge material and design are related to animal usage and existing infrastructure and can shape public views that build or jeopardize public trust.
Article
Full-text available
Shared habitats between humans and other animals are increasing in the twenty-first century, which may require behavioral flexibility from animal species to adjust to these new environments. We evaluated the effects of anthropogenic pressure on Geoffroy’s spider monkeys (Ateles geoffroyi) in a low-impact tourism area. Over the course of 18 months, we repeatedly assessed the presence of spider monkeys at 49 sampling locations for a total of 98 hours of point-count sampling and 6,768 hours of passive acoustic monitoring. Combining these data, we assessed the effects of human settlements, recreational areas, forest loss, and anthropogenic noise on spider monkey abundance using Royle–Nichols models. We found positive associations of various sources of anthropogenic pressure with spider monkey abundance. We interpret the results as Geoffroy´s spider monkeys habituating to various sources of anthropogenic pressure, and conclude that the species has the potential to live in low-impacted habitats shared with humans, but that conservation efforts should focus on evaluating the risk of human–wildlife conflict emergence. By combining our multi-method survey with Royle–Nichols statistical models, we offer a flexible approach to monitor primate populations with a high degree of fission–fusion dynamics, while controlling for heterogeneity in detection probability.
Presentation
Although wildlife bridges have been shown to aid nonhuman primates by connecting fragmented habitats, the evaluation of crossing structure (CS) design is a fledgling field of study in primatology. To address this problem, we evaluated CS preference and performance among three Neotropical primate species (Alouatta palliatta, n=4 individuals; Cebus capucinus, n=3; and Ateles geofroyii, n=3) at a rescue center in Puerto Viejo de Talamanca, Costa Rica. We tested the hypothesis that the monkeys prefer bridges that are relatively stiff. Study subjects were given uniform access to five models varying in stiffness and width during 27 sampling hours in July 2015. Model preference and performance was assessed by sampling focal individuals’ behavior and estimating bridge crossing rates. Our results show that there was a clear difference between bridge models in crossing events (N=122, x2= 10.4335, df= 4, p=0.0337). The least popular model was used in 6.7% of the crossings and the most used bridge comprised 41% of our sample. Moreover, the most popular CS model had a high degree of stiffness, indicating that this material property may be a determinate of CS preference. On the other hand, the least popular model is less stiff or stable. Our findings provide a better understanding of CS design for nonhuman primates and may be incorporated into biological corridor management. This research was supported by the Riverbanks Conservation Support Fund.
Article
Full-text available
Over the past decades, primate populations have been declining. Four years ago, >60% of species were listed as threatened. As the rate of loss accelerates and new IUCN assessments are being published, we used IUCN Red List assessments and peer-reviewed literature published within the last 5 yr to evaluate the status of primates globally, by region and by taxonomic group. We also examined the main factors affecting a species' conservation status to determine if we could predict the status of understudied species. We found that 65% of species are in the top three IUCN Red List categories (Vulnerable, Endangered, Critically Endangered). Globally, the main threats to primates are Biological Resource Use, including Hunting & Logging, and Agriculture. The impact of these threats varied by region and taxon. Our model showed that Malagasy and Asian primates, and those affected by Agriculture, Human Disturbance, and Climate Change were more likely to be considered at risk of extinction. The model's predictive probability, however, was low. Our literature analysis showed that some threats, especially climate change and disease, affected more species than indicated by the IUCN Red List. As we move into the next decade, we must continue tackling hunting and agricultural expansion but also be vigilant about emerging threats. We must also aim to regularly test the effectiveness of mitigation strategies, evaluating their long-term adoption and their impact on primates; as well as to increase communication between researchers and applied conservationists to ensure IUCN assessments include current and emerging threats. Supplementary information: The online version contains supplementary material available at 10.1007/s10764-021-00242-2.
Poster
Full-text available
Los puentes pasafauna, son estructuras artificiales que conectan fragmentos de hábitat natural interrumpidos por infraestructura linear. Estos puentes pueden proveer paso seguro para monos al conectar el dosel del bosque y reducir muertes por actividades antropogénicas. Problema: La importancia del diseño estructural de los puentes pasafauna para monos es un área muy poco estudiada. Preguntas de investigación: ¿Cómo afecta el diseño estructural y los materiales al uso del puente por los monos? ¿Hay diferencias en el uso del puente entre especies?
Article
Full-text available
All gibbon species (Primates: Hylobatidae) are facing high extinction risk due to habitat loss and hunting. The Hainan gibbon Nomascus hainanus is the world’s most critically endangered primate, and one of the priority conservation actions identified is to establish artificial canopy corridors to reconnect fragmented forests. The effectiveness of artificial canopy bridge as a conservation tool for wild gibbons has not been widely tested, and the results are rarely published. We constructed the first canopy bridge for Hainan gibbon in 2015 to facilitate passage at a natural landslide; mountaineering-grade ropes were tied to sturdy trees with the help of professional tree climbers and a camera trap was installed to monitor wildlife usage. Hainan gibbon started using the rope bridge after 176 days, and usage frequency increased with time. All members in the gibbon group crossed the 15.8 m rope bridge except adult male. Climbing was the predominant locomotor mode followed by brachiation. This study highlights the use and value of rope bridges to connect forest gaps for wild gibbons living in fragmented forests. While restoring natural forest corridors should be a priority conservation intervention, artificial canopy bridges may be a useful short-term solution.
Article
Full-text available
Fragmentation caused by linear infrastructures is a threat to forest-dwelling wildlife globally. Loss of canopy connectivity is particularly problematic for highly arboreal species such as those of the Neotropics. We explored the use of both natural canopy bridges (NCBs) and a semi-artificial one over a natural gas pipeline right-of-way (RoW) in the Peruvian Amazon to provide more information on both a proven and a novel solution to the problem of fragmentation. We monitored seven NCBs over 14 months and found crossing rates higher than previously recorded (57.70 crossings/100 trap nights by 16 species). We also constructed a semi-artificial canopy bridge (SACB) out of a liana and found it to be used quickly (seven days after installation) and frequently (90.23 crossings/100 trap nights—nearly nightly) by five species (two procyonids, one didelphid, one primate, and one rodent). This information contributes to our knowledge of mitigation solutions for fragmentation. As linear infrastructure grows globally, more solutions must be developed and tested.
Article
Full-text available
The Nuevo Xcan-Playa del Carmen highway in Quintana Roo, bisects the vegetation corridor connecting two Jaguar Conservation Units (JCUs): Yum Balaam (north) and Sian Ka´an (south). The project´s main goal was to describe differential use of available crossing structures (wildlife underpasses and culverts) by mammals present along this highway. We set 28 camera traps along the 54km stretch of the highway covering wildlife underpasses (10), and culverts such as box culverts (9) and pipes (9) from September 2016 until March 2017. A total of 24 jaguar crossings have been recorded exclusively using wildlife underpasses, including four males and two females. At least 18 other mammal species including five of the target priority species (protected by Mexican law) were documented, all of which were native except for two invasive species. In terms of species using the crossing structures, we identified 13 species using wildlife underpasses, nine using concrete box culverts and 10 using concrete pipes. Wildlife underpasses show higher diversity values (Shannon´s exponential index = 5.8 and Inverse Simpson´s index = 4.66) compared to culverts because they allow bigger species to cross. We recommend more highways along the jaguar´s distribution should develop mitigation measures to allow for wildlife connectivity. Wildlife underpasses, along with retrofitted culverts, could help secure not only the permanence of this species by facilitating the functional connectivity between populations but have positive impacts on other neotropical mammalian fauna as well.
Article
Full-text available
The Thin-spined Porcupine (Chaetomys subspinosus) is a medium-sized and mainly arboreal rodent, endemic to the Brazilian Atlantic Forest, and threatened with extinction. Habitat loss, hunting, forest fires, agriculture and livestock are threats identified for the species. Here we raise the alert to the impact of roads on remaining populations of C. subspinosus based on roadkill records from the state of Espírito Santo, southeastern Brazil. Mortality due to roadkill is likely to impact C. subspinosus in different regions of the state, and is a widespread problem, not unique to a single location or population. The pattern of roadkills in the studied regions suggest that the species is more susceptible to collisions with vehicles in the breeding period. Additionally, concrete barriers that divide lanes on highways seens to increase the likelihood of roadkill for Thin-spined Porcupines. We recommend that roadkill should be included in the list of threats to C. subspinosus in the Espírito Santo. Mortality due to roadkill is probably relevant also for populations in the states of Bahia and Sergipe, and it should be evaluated locally. The installation of road-crossing structures for wildlife, such as arboreal overpasses, is recommended on roads crossing or close to protected areas with C. subspinosus presence in Espírito Santo and elsewhere.
Article
Full-text available
Linear infrastructure development and resulting habitat fragmentation are expanding in Neotropical forests, and arboreal mammals may be disproportionately impacted by these linear habitat clearings. Maintaining canopy connectivity through preservation of connecting branches (i.e. natural canopy bridges) may help mitigate that impact. Using camera traps, we evaluated crossing rates of a pipeline right-of-way in a control area with no bridges and in a test area where 13 bridges were left by the pipeline construction company. Monitoring all canopy crossing points for a year (7,102 canopy camera nights), we confirmed bridge use by 25 mammal species from 12 families. With bridge use beginning immediately after exposure and increasing over time, use rates were over two orders of magnitude higher than on the ground. We also found a positive relationship between a bridge’s use rate and the number of species that used it, suggesting well-used bridges benefit multiple species. Data suggest bridge use may be related to a combination of bridge branch connectivity, multiple connections, connectivity to adjacent forest, and foliage cover. Given the high use rate and minimal cost, we recommend all linear infrastructure projects in forests with arboreal mammal populations include canopy bridges.
Conference Paper
Full-text available
Road and pipeline right-of-way construction in high-diversity tropical rainforest has isolated populations of arboreal animals that depend on the canopy as their principal habitat and pathways. Walsh and Petroamazonas EP developed a robust and safe engineering solution to recreate canopy connection using artificial canopy bridges spanning up to 35 m across a multi-use corridor to facilitate the movement of arboreal mammals in ecologically protected areas in Ecuador. The following criteria were used for design and installation of artificial canopy bridges: resistance to wind, movement of trees, and decay; facilitate the sway of trees; tested at a zoo for animal acceptance and resistance to chewing; installation in robust trees with minimal root damage during earth movement; locate in areas with arboreal presence or "canopy trails", install at a sufficient height as not to interfere with the field logistics, use light-weight materials so the bridges could transported and installed without the use of motorized equipment. Wildlife cameras were installed to record use by arboreal mammals. Trained arborists and tree-climbers strung ropes through branch crotches and scaled the anchor trees. Anchor holes were drilled (between 10 m and 25 m above the ground surface) with potable electric drills in trunks and large branches; treaded rod and eyebolt anchors were installed in these holes; the bridges were then raised, attached and adjusted; and finally motion and heat activated cameras were installed to record (day and night) animal use over time. Six (6) bridges were installed across a right-of-way consisting of a road with an adjacent pipeline, communication cable and power cable; and five (5) bridges were installed across a cross-country pipeline. These artificial canopy bridges have been designed to last over 10 years, which will allow for natural regrowth of branches across the right-of-way and reconnection of the canopy. The motion and heat-activated cameras included sealant and desiccant to avoid damage from humidity, and were bolted to tree trunks on brackets to properly orient the lens towards the bridges and resist animal damage. The eight (8) installed cameras have been collecting photos for approximately 11 months. The following animals have been photographed on or near the bridges: olingo, porcupine, and various species of monkeys. This experiment in recreating canopy connection demonstrates that fragmented arboreal habitats can be reconnected artificially in areas where natural canopy bridges cannot be maintained due to wide right-of ways. These artificial bridges and motion and heat activated cameras provide an important research opportunity for biologists studying behavior of arboreal animals, since canopy access is logistically challenging.
Chapter
Full-text available
The Monkey Bridge Project began in 2006 in order to minimize the influence of habitat fragmentation due to urban development within primate ranges in the Caribe Sur region of Costa Rica. The majority of research has focused on evaluating the effectiveness of artificial crossing structures (i.e., wildlife bridges) and natural canopy crossings in a peri-urban landscape for reducing mortality risks in nonhuman primates. In addition, this study used an ethnoprimatological approach to examine sociocultural drivers of habitat fragmentation and their impacts on nonhuman primates. Results show that although roads and power lines represent a major risk, primates rarely used artificial crossings. Other mammals, however, commonly used these structures. Furthermore, a rise in the number of natural canopy bridges occurred over 9 years and preliminary findings suggest that monkeys may favor natural canopy crossings. These simple “corridors” have the potential to complement larger habitat preservation efforts in the region and contribute to the broader goals of connecting habitat fragments and growing synergistic relationships between human and nonhuman primates in the Caribe Sur.
Chapter
Full-text available
Diani is an international tourist destination located on the south coast of Kenya. This chapter addresses the issue of primate injury and death caused by wildlife-vehicle collision (WVC), the Colobus Conservation installed the first canopy bridge in 1997, locally known as a 'colobridge'. A preliminary study in 2011 assessed traffic volume along the Diani Beach Road and rate of use of the canopy bridges. It is important to note that canopy bridges may not be used by larger primates or those of a terrestrial nature. Between 1999 and 2012, 518 monkeys were injured or killed by vehicles on the Diani Beach Road. This is approximately a 3% loss in the local primate population annually. Though no data is available on primate road injury or mortality prior to our colobridge installations, we believe that bridge use represents a significant reduction in risk of mortality for each crossing event.
Article
Full-text available
The banded leaf monkey (Presbytis femoralis femoralis) is critically endangered in Singapore and affected by widespread deforestation in southern Peninsular Malaysia. The Singapore population has recovered from a low of 15–20 to more than 40 individuals, but prior to our study it was unclear how severely the past bottleneck had depleted the genetic diversity of the population. Here, we provide the fi rst analysis of the genetic variability based on seven samples (ca. 20% of population) collected over two years of fi eldwork. We fi nd only two haplotypes that differ only in one variable site for the hypervariable region I (HV-I) of the mitochondrial d-loop. Compared to available population-level data for other colobines (proboscis monkey, Yunnan snub-nosed monkey, Sichuan snub-nosed monkey, Angolan black and white colobus), the banded leaf monkey population in Singapore has the lowest number and the most similar haplotypes. This low genetic variability is the next challenge for the conservation of the population. Protected habitats in prospering urban environment may become important sanctuaries for endangered species, but reintroductions may have to be considered in order to restore genetic variability that was lost during past bottlenecks.
Chapter
Full-text available
Spider monkeys are one of the most widespread New World primate genera, ranging from southern Mexico to Bolivia. Although they are common in zoos, spider monkeys are traditionally very difficult to study in the wild, because they are fast moving, live high in the canopy and are almost always found in small subgroups that vary in size and composition throughout the day. This book is an assimilation of both published and previously unpublished research. It is a comprehensive source of information for academic researchers and graduate students interested in primatology, evolutionary anthropology and behavioral ecology and covers topics such as taxonomy, diet, sexuality and reproduction, and conservation.
Article
Full-text available
Neotropical monkeys of the genera Cacajao, Chiropotes, and Pithecia (Pitheciidae) are considered to be highly arboreal, spending most of their time feeding and traveling in the upper canopy. Until now, the use of terrestrial substrates has not been analyzed in detail in this group. Here, we review the frequency of terrestrial use among pitheciin taxa to determine the ecological and social conditions that might lead to such behavior. We collated published and unpublished data from 14 taxa in the three genera. Data were gleaned from 53 published studies (including five on multiple pitheciin genera) and personal communications of unpublished data distributed across 31 localities. Terrestrial activity was reported in 61% of Pithecia field studies (11 of 18), in 34% of Chiropotes studies (10 of 29), and 36% of Cacajao studies (4 of 11). Within Pithecia, terrestrial behavior was more frequently reported in smaller species (e.g. P. pithecia) that are vertical clingers and leapers and make extensive use of the understory than in in the larger bodied canopy dwellers of the western Amazon (e.g. P. irrorata). Terrestrial behavior in Pithecia also occurred more frequently and lasted longer than in Cacajao or Chiropotes. An apparent association was found between flooded habitats and terrestrial activity and there is evidence of the development of a "local pattern" of terrestrial use in some populations. Seasonal fruit availability also may stimulate terrestrial behavior. Individuals also descended to the ground when visiting mineral licks, escaping predators, and responding to accidents such as a dropped infant. Overall, the results of this review emphasize that terrestrial use is rare among the pitheciins in general and is usually associated with the exploitation of specific resources or habitat types. Am. J. Primatol. 00:1-22, 2012. © 2012 Wiley Periodicals, Inc.
Article
Full-text available
Roads are a widespread and increasing feature of most landscapes. We reviewed the scientific literature on the ecological effects of roads and found support for the general conclusion that they are associated with negative effects on biotic integrity in both terrestrial and aquatic ecosystems. Roads of all kinds have seven general effects: mortality from road construction, mortality from collision with vehicles, modification of animal behavior, alteration of the physical environment, alteration of the chemical environment, spread of exotics, and increased use of areas by humans. Road construction kills sessile and slow-moving organisms, injures organisms adjacent to a road, and alters physical conditions beneath a road. Vehicle collisions affect the demography of many species, both vertebrates and invertebrates; mitigation measures to reduce roadkill have been only partly successful. Roads alter animal behavior by causing changes in home ranges, movement, reproductive success, escape response, and physiological state. Roads change soil density, temperature, soil water content, light levels, dust, surface waters, patterns of runoff, and sedimentation, as well as adding heavy metals (especially lead), salts, organic molecules, ozone, and nutrients to roadside environments. Roads promote the dispersal of exotic species by altering habitats, stressing native species, and providing movement corridors. Roads also promote increased hunting, fishing, passive harassment of animals, and landscape modifications. Not all species and ecosystems are equally affected by roads, but overall the presence of roads is highly correlated with changes in species composition, population sizes, and hydrologic and geomorphic processes that shape aquatic and riparian systems. More experimental research is needed to complement post-hoc correlative studies. Our review underscores the importance to conservation of avoiding construction of new roads in roadless or sparsely roaded areas and of removal or restoration of existing roads to benefit both terrestrial and aquatic biota. Resumen: Las carreteras son una característica predominante y en incremento de la mayoría de los paisajes. Revisamos la literatura científica sobre los efectos ecológicos de las carreteras y encontramos sustento para la conclusión general de que las carreteras están asociadas con efectos negativos en la integridad biótica tanto de ecosistemas terrestres como acuáticos. Las carreteras de cualquier tipo ocasionan siete efectos generales: mortalidad ocasionada por la construcción de la carretera; mortalidad debida a la colisión con vehículos; modificaciones en la conducta animal; alteración del ambiente físico; alteración del ambiente químico; dispersión de especies exóticas e incremento en el uso de áreas por humanos. La construcción de carreteras elimina a organismos sésiles y a organismos de lento movimiento, lesiona a organismos adyacentes a la carretera y altera las condiciones físicas debajo ella misma. Las colisiones con vehículos afectan la demografía de muchas especies tanto de vertebrados como invertebrados; las medidas de mitigación para reducir la pérdida de animales por colisiones con vehículos han sido exitosas solo de manera parcial. Las carreteras alteran la conducta animal al ocasionar cambios en el rango de hogar, movimientos, éxito reproductivo, respuesta de escape y estado fisiológico. Las carreteras cambian la densidad del suelo, temperatura, contenido de agua en el suelo, niveles de luz, polvo, aguas superficiales, patrones de escurrimiento y sedimentación, además de agregar metales pesados (especialmente plomo), sales, moléculas orgánicas, ozono y mutrientes a los ambientes que atraviesan. Las carreteras promueven la dispersión de especies exóticas al alterar los hábitats, al estresar a las especies nativas y proveer corredores para movimiento. Las carreteras también promueven el incremento de la caza y la pesca, el hostigamiento pasivo de animales y modificaciones del paisaje. No todas las especies ni todos los ecosistemas son afectados por las carreteras de igual forma, pero en general la presencia de carreteras está altamente correlacionada con cambios en la composición de especies, los tamaños poblacionales y los procesos hidrológicos y geomorfológicos que afectan a la estructura de sistemas acuáticos y reparios. Se necesita más investigación experimental para complementar estudios correlativos post-hoc. Nuestra revisión hace énfasis en que en trabajos de conservación es importante evitar la construcción de nuevas carreteras en áreas carentes de ellas o en áreas con pocas carreteras, además de remover o restaurar carreteras existentes con la finalidad de beneficiar tanto a la biota acuática como la terrestre.
Article
Full-text available
Spider monkeys (Ateles spp.) are well known for their highly arboreal lifestyle, spending much of their time in the highest levels of the canopy and rarely venturing to the ground. To investigate terrestriality by Ateles and to illuminate the conditions under which spider monkeys venture to the ground, we analyzed ad libitum data from 5 study sites, covering 2 species and 5 subspecies. Three of the sites are in Central/North America: Barro Colorado Island (BCI), Panama (Ateles geoffroyi panamensis), Santa Rosa National Park, Costa Rica (A. g. frontatus), and Punta Laguna, Mexico (A. g. yucatanensis). The 2 remaining sites are in South America: Cocha Cashu Biological Station, Perú (A. belzebuth chamek) and Yasuni National Park, Ecuador (A. b. belzebuth). Terrestrialism by Ateles at all sites is rare; however, it is more restricted at the 2 South American sites. In South America, ground use only occurred in the contexts of eating soil or rotten wood and visiting salt licks. In contrast at the 3 sites with Ateles geoffroyi it rarely occurred in a feeding context, but instead more frequently while drinking from streams during the dry season, by adult females escaping attack by adult males, and as part of a chase game. In addition, on BCI adult males were on the ground before attacking adult females. We discuss potential explanations, e.g., climate, species differences, predation pressure, for the differences between the Central/North and South American observations.
Article
There are few highways in Mexico that have built canopy bridges as a mitigation strategy for maintaining connectivity of arboreal fauna. Main target species have been primates, both, howler (Allouatta pigra, A. palliata) and spider monkeys (Atteles geofforyi), as well as several other arboreal priority species such as the kinkajou (Potos flavus), the northern tamandua (Tamandua mexicana) and the Mexican hairy porcupine (Sphiggurus mexicanus). The Nuevo Xcan-Playa del Carmen highway built 22 canopy bridges along its 54 km length. All bridges were surveyed using camera traps installed at both ends and after an 8,418 trap/night effort, 10 records of four mammal species were recorded using the canopy bridges: the kinkajou, opossum (Didelphis virginiana) and squirrels (Sciurus deppei and S. yucatanensis). More monitoring is required to properly assess the effectiveness of these mitigation measures, as the need for cost/benefit feedback is necessary to enhance further mitigation in this or other projects. Also, long term monitoring is required for properly assessing the use patterns of species. The current study was shortly after the infrastructure became operational, so it covers the adaptation period for several species but its insufficient to properly assess the current use.
Article
Roads affect the integrity of ecosystems worldwide as a cause of mortality to animals and a barrier to animal movement, decreasing gene flow and increasing local extinction probability. It is estimated that construction of linear infrastructure impacts up to 13% of primate species but research focusing on primate road fatalities and mitigation is not extensive and experimental research on canopy crossing designs for primates is lacking. We used the South African samango monkey (Cercopithecus albogularis) as a model species to test suitable bridge design through field experimentation and behavioural data collection for arboreal guenon roadkill mitigation and a mapped actual roadkill data in the region. We show that canopy overpasses are a viable intervention for mitigating arboreal guenon road fatalities, reducing the probability that monkeys will cross a road on the ground. Samango monkeys clearly preferred a pole bridge over a rope ladder design and canopy bridges were preferred to trees and the ground when the tree canopy was open. Pole bridges were also used by other non-guenon and non-primate species. Although samango roadkills are not predictable in time (no seasonality), adult female and immature fatalities are predictable in space, restricted to bisected riparian zones and roads close to intact forests. Adult male road fatalities can also be expected in seemingly unsuitable habitat areas. Our study shows how important correct interpretation of spatial, temporal and demographic data on road fatalities is and how experimental research prior to installing crossing structures could increase mitigation impact.
Article
Canopy bridges are increasingly used to reduce fragmentation in tropical habitats yet monitoring of their impact on the behavior of primates remains limited. The Javan slow loris (Nycticebus javanicus) is endemic to Java, Indonesia, where the species most often occurs in human-dominated, highly patchy landscapes. Slow lorises cannot leap, are highly arboreally adapted, and are vulnerable on the ground. To increase arboreal connectivity, as part of a long-term conservation project in Cipaganti, West Java, we built and monitored seven slow lorises bridges of two types-waterline or rubber-and monitored their use by seven adult individuals from 2016 to 2017. Motion triggered camera traps collected data for 195 ± standard deviation (SD) 85 days on each bridge. We collected 341.76 hr (179.67 hr before and 162.09 hr after the installation of bridges) of behavioral and home range data via instantaneous sampling every 5 min, and terrestrial behavior (distance and duration of time spent on the ground) via all occurrences sampling. We found that slow lorises used bridges on average 12.9 ± SD 9.7 days after their installment mainly for traveling. Slow lorises showed a trend toward an increase in their home range size (2.57 ha before, 4.11 ha after; p = 0.063) and reduced ground use (5.98 s/hr before, 0.43 s/hr; p = 0.063) after implementation of bridges. Although the number of feeding trees did not change, new feeding trees were included in the home range, and the proportion of data points spent traveling and exploring significantly decreased (p = 0.018). Waterline bridges serve a purpose to irrigate the crops of local farmers who thus help to maintain the bridges, and also ascribe value to the presence of slow lorises. Other endemic mammal species also used the bridges. We advocate the use and monitoring of artificial canopy bridges as an important supplement for habitat connectivity in conservation interventions.
Article
Arboreal fauna living in tropical ecosystems may be particularly affected by roads given their dependency on forest cover and the high vulnerability of such ecosystems to changes. Over a period of 4 yr, we followed subgroups of spider monkeys living in a regenerating dry tropical forest with 8.2 km of roads within their home range. We aimed to understand whether roads shaped the home range of spider monkeys and which road features affected their movement. Only 18 percent (3 km) of the spider monkeys' home range perimeter bordered with roads; these roads had greater habitat disparity between road sides than roads inside the home range. Although monkeys were reluctant to be close to roads, and roadside habitat contained low proportions of mature forest, spider monkeys crossed roads at 69 locations (7.5 crossings per kilometer). The main road characteristic affecting crossings was canopy opening size, with greater probability of crossing where canopy openings were smaller. Our findings support the importance of canopy opening size for road crossing of arboreal taxa, but they also indicate the relevant role roadside forest structure may have. Minimizing canopy opening size and forest disturbance along roads can facilitate the movement of arboreal fauna and preserve the important role of spider monkeys and other arboreal taxa in seed dispersal and thus the maintenance and regeneration of forest diversity.
Article
The Ambatovy Project includes a large, open-pit nickel mine located in Madagascar's eastern humid forest, and an associated pipeline to remove laterite slurry off site. The area is recognized for its high biodiversity exemplified by the presence of at least 13 lemur species in forests surrounding the mine site. In order to reduce potential habitat fragmentation impacts on the lemur populations as a consequence of recent access road construction, seven crossing structures (referred to as 'lemur bridges') were erected within the mine footprint area and along the slurry pipeline that will remain in place until rehabilitated forest allows for movement over roads via the forest canopy. Two bridge designs were used due to differences in road width and vehicle traffic type. Lemur bridges have been monitored since their construction in January-February 2009. To date (10 August 2010), bridges have been used by six lemur species. Mine footprint type bridges (suspension bridge design) have been used more frequently than slurry pipeline bridges (plank bridge design) and, overall, there has been an increase in bridge use in 2010 when compared to 2009 (from 8% to 24% of total observations where lemurs are present in proximity to bridges). These results suggest that although a certain time period may be required for lemurs to locate and habituate to bridges, these crossing structures offer an effective mitigation measure to assist in reducing the impacts of habitat fragmentation.
Article
A system of natural reserves, each surrounded by altered habitat, resembles a system of islands from the point of view of species restricted to natural habitats. Recent advances in island biogeography may provide a detailed basis for understanding what to expect of such a system of reserves. The main conclusions are as follows:The number of species that a reserve can hold at equilibrium is a function of its area and its isolation. Larger reserves, and reserves located close to other reserves, can hold more species.If most of the area of a habitat is destroyed, and a fraction of the area is saved as a reserve, the reserve will initially contain more species than it can hold at equilibrium. The excess will gradually go extinct. The smaller the reserve, the higher will be the extinction rates. Estimates of these extinction rates for bird and mammal species have recently become available in a few cases.Different species require different minimum areas to have a reasonable chance of survival.Some geometric design principles are suggested in order to optimise the function of reserves in saving species.
Article
Linear infrastructure such as roads, highways, power lines and gas lines are omnipresent features of human activity and are rapidly expanding in the tropics. Tropical species are especially vulnerable to such infrastructure because they include many ecological specialists that avoid even narrow (<30-m wide) clearings and forest edges, as well as other species that are susceptible to road kill, predation or hunting by humans near roads. In addition, roads have a major role in opening up forested tropical regions to destructive colonization and exploitation. Here, we synthesize existing research on the impacts of roads and other linear clearings on tropical rainforests, and assert that such impacts are often qualitatively and quantitatively different in tropical forests than in other ecosystems. We also highlight practical measures to reduce the negative impacts of roads and other linear infrastructure on tropical species.
Ateles geoffroyi (amended version of 2020 assessment)
  • L Cortes-Ortíz
  • D Solano-Rojas
  • M Rosales-Meda
  • K Williams-Guillén
  • P G Méndez-Carvajal
  • L K Marsh
  • D Canales-Espinosa
  • R A Mittermeier
  • Cortes-Ortíz L
Cortes-Ortíz L, Solano-Rojas D, Rosales-Meda M, Williams-Guillén K, Méndez-Carvajal PG, Marsh LK, Canales-Espinosa D, Mittermeier RA (2021). Ateles geoffroyi (amended version of 2020 assessment). The IUCN Red List of Threatened Species 2021: e.T2279A191688782. DOI: 10.2305/IUCN.UK.2021-1.RLTS.T2279A 191688782.en. Accessed on 22 January 2022.
Endangered Brazilian monkeys get a bridge to themselves
  • M De Sousa
  • M Lobao
  • de Sousa M
de Sousa M, Lobao M (2020). Endangered Brazilian monkeys get a bridge to themselves [Internet].
Central American Spider Monkey Ateles geoffroyi Kühl, 1820. In Primates in Peril: the World's 25 Most Endangered Primates
  • P G Méndez-Carvajal
  • M E Rodríguez
  • Pozo Montuy
  • G Chaves
  • Ó M Ponce
  • G Rodríguez-Beitia
Méndez-Carvajal PG, Rodríguez ME, Pozo Montuy G, Chaves ÓM, Ponce G, Rodríguez-Beitia BA, et al. (2019). Central American Spider Monkey Ateles geoffroyi Kühl, 1820. In Primates in Peril: the World's 25 Most Endangered Primates 2018-2020 (Schwitzer C, Mittermeier RA, Rylands AB, Chiozza F, Williamson EA, Byler D, et al., eds.), pp. 98-101. Washington D.C., IUCN SSC Primate Specialist Group, International Primatological Society, Global Wildlife Conservation, and Bristol Zoological Society.
Monitoreo del jaguar, otros felinos silvestres y sus especies presa en el cantón central de Limón, Costa Rica. Informe final para CCT-APM Terminals
  • Panthera
Panthera (2019). Monitoreo del jaguar, otros felinos silvestres y sus especies presa en el cantón central de Limón, Costa Rica. Informe final para CCT-APM Terminals, Costa Rica.
Etude sur la qualite et l’efficacite des corridors ecologiques de la RN 2 en Guyane
  • K Pineau
  • E Mirouze
  • V Rufray
  • Pineau K
Pineau K, Mirouze E, Rufray V (2016). Etude sur la qualite et l'efficacite des corridors ecologiques de la RN 2 en Guyane.
Monitoreo de mamíferos del Proyecto Carretero Ramales Cedral-Tintal y Tintal-Playa del Carmen con una longitud de 54 km, en el estado de Quintana Roo
  • Sega Sa De Cv
SEGA SA de CV (2014). Monitoreo de mamíferos del Proyecto Carretero Ramales Cedral-Tintal y Tintal-Playa del Carmen con una longitud de 54 km, en el estado de Quintana Roo. Noviembre 2012-Septiembre 2013.
First use of artificial canopy bridge by the world’s most critically endangered primate the Hainan gibbon Nomascus hainanus
  • Bpl Chan
  • Yfp Lo
  • X-J Hong
  • C F Mak
  • Z Ma
  • Chan BPL
Natural canopy bridges effectively mitigate tropical forest fragmentation for arboreal mammals
  • T Gregory
  • F Carrasco-Rueda
  • Alonso A Kolowski
  • J Deichmann
  • Gregory T
Mammal use of canopy bridges along the Nuevo Xcan-Playa del Carmen highway
  • M Hidalgo-Mihart
  • A González-Gallina
  • J A Iglesias-Hernández
  • N Mendoza-Cárdenas
  • F Pérez-Garduza
  • A Chacón-Hernández
  • O Vázquez-Zúñiga
  • Hidalgo-Mihart M
Lemur bridges provide crossing structures over roads within a forested mining concession near Moramanga, Toamasina Province, Madagascar
  • V Mass
  • B Rakotonmanga
  • G Rakotondratsimba
  • S Razafindramisa
  • P Andrianaivomahefa
  • S Dickinson
  • Mass V
Central American Spider Monkey Ateles geoffroyi Kühl, 1820
  • P G Méndez-Carvajal
  • M E Rodríguez
  • Pozo Montuy
  • G Chaves
  • Ó M Ponce
  • G Rodríguez-Beitia
  • Méndez-Carvajal PG
The Human-Alloprimate Interface in Gandoca, Costa Rica. An Ethnoprimatological Approach to Assess Conflict Between Residents and Three Neotropical Primates
  • G Narvaez Rivera
  • Narvaez Rivera G