The Influence of Landscape Structure on the Occurrence of Neospora caninum, Toxoplasma gondii, and Sarcocystis spp. in Free-Living Neotropical Primates

PURPOSE

Habitat fragmentation is the main threat to primate survival in the world. Additionally, changes in the environments in which they live can also contribute to exposure to pathogens. To investigate some pathogens that free-living primates may be exposed to in Rio Grande do Sul State (RS; southern Brazil) and characterize the forest remnants in which they live, we investigated anti-Neospora caninum, Toxoplasma gondii, and Sarcocystis spp. antibodies in the serum of the animals.

METHODS

We analyzed 105 serum samples from 63 black howler monkeys (Alouatta caraya), 39 southern brown howler monkeys (Alouatta guariba clamitans), and 03 capuchin monkeys (Sapajus nigritus cucullatus), which were captured in forest fragments of RS. Indirect fluorescence antibody test (IFAT) and indirect hemagglutination assay (IHA) were used to detect antibodies to the agents. We then characterized the landscapes in a multiscale approach in radii from 200 to 1400 m to investigate the relationship of the presence of the agents with landscape elements.

RESULTS

In the IFAT-IgG, 13.3% (14/105) of the samples were seropositive for N. caninum, 4.8% (5/105) for T. gondii, and 5.7% (6/105) for Sarcocystis spp. In the IHA-IgM/IgG, 24.8% (26/105) were seropositive for T. gondii. The metrics that best explained exposure to agents were edge and patch density, forest cover, urban cover, and average Euclidean distance to the nearest patch.

CONCLUSIONS

This study indicated that the primates were exposed to the agents studied, demonstrating that some landscape features are associated with exposures to the investigated pathogens.

Artificialcanopy bridge use by primates and other arboreal mammals in a fragmented tropical forest of northeast Bangladesh

Forest fragmentation has resulted in a breakdown in connectivity for arboreal species. Effects of fragmentation are particularly acute in forest patches in densely populated countries, resulting in high mortality in many species attempting to cross roads to travel between forest patches. We evaluated the use of three, single-line artificial canopy bridges made of polypropylene ropes in a forest patch in northeastern Bangladesh. Camera traps were used to determine the extent of bridge use by different species. A total of 1060 events of bridge use by mammals were observed using our artificial canopy bridges over the 157 camera trap days. Eight mammal species, including five primate species, two squirrel species and one palm civet species were recorded using the bridges at varying levels of frequency. The location of the bridge and season influenced bridge use. We did not observe mortality of mammals from road accidents or electrocution during the study period. We suggest that artificial canopy bridges increased connectivity between forest patches and reduced mortality from road accidents and electrocution. We strongly recommend the use of this and other, simple canopy bridges to prevent mortality of arboreal mammals.

Community-level awareness and attitudes towards human-monkey conflict in Polonnaruwa district, Sri Lanka

As the demand for resources has increased with the high population growth rate, people have been tempted to encroach on wildlife areas for activities such as logging, animal husbandry, agriculture, and developmental projects. This has led to the spread of human-inhabited areas into wildlife habitats and resulting conflict between humans and wildlife. Human-monkey conflict (HMC) is a developing issue in Sri Lanka, negatively impacting both nonhuman primate conservation and human welfare. To address and mitigate HMC, it is essential to assess community-level awareness about nonhuman primates in order to mitigate such conflict. The aim of this study was to evaluate awareness and public perception towards diurnal monkeys in Polonnaruwa district in North Central Sri Lanka. A structured questionnaire survey (N = 200) was carried out from December 2018 to November 2019. Respondents' knowledge about monkeys was found to depend on gender and occupation. Respondents' attitudes towards monkeys were dependent on gender, ethnic group, religion, state of education, and monthly household income. Those who had experienced many disturbances from monkeys held more negative attitudes towards monkeys than others. A nonlethal multidisciplinary approach is critical to reducing the increasing HMC in Polonnaruwa district. Similar approaches can be operated in other areas where human-wildlife conflict is causing strain on wildlife conservation and human welfare.

Crop and property damage caused by Purple-faced Langurs Trachypithecus vetulus (Mammalia: Primates: Cercopithecidae)

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The costs and benefits of coexistence: What determines people's willingness to live near nonhuman primates?

Living near primate species has positive and negative outcomes for human communities. While most studies focus on understanding people's perceptions regarding the adverse consequences of interacting with primates, less is known about people's willingness to coexist with primates or reasons that may promote human-primate coexistence. We surveyed 794 people co-living with four different primate species-rhesus macaque Macaca mulatta, bonnet macaque Macaca radiata, lion-tailed macaque Macaca silenus, and Hanuman langur Semnopithecus dussumieri-in southern and western India to understand how people perceived the costs and benefits of coexistence. The results of our semi-structured interview study revealed that although tangible costs (i.e., financial losses from primate depredation) primarily drive people's stated tolerance for primate presence, intangible benefits from primates (i.e., their ecological, existence, sentience, and religious values) also critically affect attitudes towards coexistence. Amongst the four species, people associated rhesus macaques with the greatest costs and fewest benefits, lion-tailed macaques with the lowest costs, and bonnet macaques with the highest benefits. People preferred lion-tailed macaques and Hanuman langurs more than bonnet and rhesus macaques, and affection for a species shaped how people viewed costs accruing from the species. People's preferences for species were influenced by their existence, ecological, and sentience values more than their religious value. We suggest that intangible benefits influence people's fondness for a primate species and this, in turn, shapes how people perceive costs resulting from the species. Hence strengthening people's perceptions of the intangible benefits they receive from primate species will improve human tolerance for living near primates. We argue that there is a need to understand the context of human-primate conflicts beyond the cost aspects and focus on the benefits to improve human-primate coexistence.

Lemur catta in small forest fragments: Which variables best predict population viability?

Habitat fragmentation is an increasingly serious issue affecting primates in most regions where they are found today. Populations of Lemur catta (ring-tailed lemur) in Madagascar's south-central region are increasingly restricted to small, isolated forest fragments, surrounded by grasslands or small-scale agriculture. Our aim was to evaluate the potential for population viability of L. catta in nine forest fragments of varying sizes (2-46 ha, population range: 6-210 animals) in south-central Madagascar, using a set of comparative, quantitative ecological measures. We used Poisson regression models with a log link function to examine the effects of fragment size, within-fragment food availability, and abundance of matrix resources (food and water sources) on L. catta population sizes and juvenile recruitment. We found a strong association between overall population size and (a) fragment size and (b) abundance of key food resources Melia azedarach and Ficus spp. (per 100 m along transect lines). Juvenile recruitment was also associated with fragment size and abundance of the two above-mentioned food resources. When the largest population, an outlier, was removed from the analysis, again, the model containing fragment size and abundance of M. azedarach and Ficus spp. was the best fitting, but the model that best predicted juvenile recruitment contained only fragment size. While our results are useful for predicting population presence and possible persistence in these fragments, both the potential for male dispersal and the extent of human disturbance within most fragments play crucial roles regarding the likelihood of long-term L. catta survival. While seven of the nine fragments were reasonably protected from human disturbance, only three offered the strong potential for male dispersal, thus the long-term viability of many of these populations is highly uncertain.

Mortality of primates due to roads and power lines in two forest patches in Bangladesh

Primates are in imminent risk of extinction due to different types of anthropogenic activities. Mortality due to road accidents and electrocution from power lines are among the major direct anthropogenic threats to the survival of primates. We collected primate mortality data from 2015 to 2017 at Lawachara National Park and Satchari National Park in northeastern Bangladesh. We recorded 27 fatalities in five species of primates caused by road accidents (n = 15) and electrocution (n = 12). Most mortality records were for Trachypithecus phayrei (Blyth, 1847) (n = 8) while the lowest recorded mortality was for Macaca mulatta (Zimmermann, 1780) (n = 3). Ninety percent of primates in Bangladesh are threatened and populations are gradually declining. Our results suggest that roads and power supply lines are major sources of primate mortality that should be managed in these two forests. We strongly suggest avoiding construction of roads and power supply lines inside forests. Furthermore, control of the speed limit of vehicles inside the forests, use of insulated power lines, maintenance of natural canopy bridges and preparation of artificial canopy bridges are strongly recommended.

Spatial Patterns of Primate Electrocutions in Diani, Kenya

Electrocution from power infrastructure threatens many primate species, yet knowledge of effective evidence-based mitigation strategies is limited. Mitigation planning requires an understanding of the spatial distribution of electrocutions to prioritize high-risk areas. In Diani, a coastal Kenyan town, electrocution is an important cause of death for five primate species. In this study we aim to describe the spatial patterns of electrocutions and electric shock incidents (collectively referred to as electrocutions hereafter) and identify electrocution hotspots to guide an effective primate conservation approach in Diani. Colobus Conservation, a not-for-profit organization, has recorded electrocutions and annual primate census data since 1998. We georeferenced 329 electrocution data points and analyzed them using QGIS. We identified and compared hotspots across species, seasons, and time using kernel density estimation and Getis-Ord-Gi*. We employed spatial regression models to test whether primate population density and power line density predicted the location of electrocution hotspots. Electrocutions occurred in hotspots that showed little variation in location between species and seasons. The limited variation in hotspot location over time likely occurred as a result of new building development in Diani and variability in primate detection rates by community members. Primate density and power line density were significant predictors of electrocution density for Angolan black-and-white colobus (Colobus angolensis palliatus) and Sykes monkeys (Cercopithecus mitis albogularis), but the relationship was weak, suggesting the presence of additional risk factors. This study provides a framework for systematic spatial prioritization of power lines that can be used to reduce primate electrocutions in Diani, and can be adopted in other areas of the world where primates are at risk from electrocution.

Is diet flexibility an adaptive life trait for relictual and peri-urban populations of the endangered primate Macaca sylvanus?

Habitat loss, fragmentation and urban expansion may drive some species to marginal habitats while others succeed in exploiting urban areas. Species that show dietary flexibility are more able to take advantage of human activities to supplement their diet with anthropogenically abundant and accessible resources. The Barbary macaque (Macaca sylvanus) is an endangered species due to the loss of its habitat, and human pressure. The population of Gouraya National Park (Algeria) lives in a relictual habitat that constitutes about 0.6% of the species range. In addition, this population is a unique case where urban expansion favours contact zones between Barbary macaque habitats and a big city (Bejaia). We quantified the dietary composition of Gouraya macaques over an annual cycle with the objective to understand how diet flexibility of this species may help it adapt to a relictual habitat or cope with urban expansion. We recorded the phenology of plant species every month. This study shows that Gouraya macaques, compared to those living in other forest types of the distribution area, are under lower seasonal constraints. They consume a greater amount of fruit and seeds that are available throughout much of the year, and a lesser amount of costly to find and extract subterranean foods. Therefore the Gouraya relictual habitat appears as a favourable environment compared to other major habitats of that species. This study also shows that colonizing peri-urban zones increases the availability and species richness of diet resources for Barbary macaques as they consume more human foods and exotic plants than in farther sites. Adult males eat more human foods than adult females and immatures do. The exploitation of high-energy anthropogenic food could favour macaque population growth and expansion towards the city center associated with human/macaque conflicts. We recommend applying management actions to restore macaques back to their natural habitat.