Wild origins and mitochondrial genetic diversity of Angolan Colobus monkeys (Colobus angolensis) in AZA-accredited zoos and its implications for ex situ population management.

Across zoo's accredited by the Association of Zoos and Aquariums (AZA), species are typically managed as a single population to retain 90% of the founding members' gene diversity. Often, little is known about the specific geographic origins of the founders or how representative the ex situ population's genetic diversity is of the wild population. This study uses mitochondrial DNA (mtDNA) sequencing to investigate haplotype diversity and geographic female founder origin of the AZA-managed Angolan colobus (Colobus angolensis) monkey population. We obtained fecal samples from individuals closely related to founder animals at five zoos and found four haplotypes among 23 individuals. Analyzed together with wild C. angolensis haplotypes, we found two haplotypes identical to those found in Tanzanian populations: one haplotype, possessed by 13 individuals (descended from three founders), matched an East Usambara Mountains haplotype, while the other, possessed by seven individuals (from four founders), matched a haplotype found in both the South Pare Mountains and Rufiji River. Two haplotypes were not detected in wild populations but were closely related to haplotypes found in the Rufiji River (one individual descended from one founder) and Shimoni, Kenya (two individuals descended from one founder) populations, suggesting nearby origins. Thus, the AZA-managed population of Angolan colobus likely originated from several localities, but all have mtDNA lineages associated with the subspecies C. a. palliatus, a Vulnerable subspecies. Examining founders' mtDNA haplotypes may be a useful addition to the zoo population management toolkit to help improve breeding recommendations by identifying individuals with rare haplotypes and revealing likely kinship among founders.

Aspects of molar form and dietary proclivities of African colobines.

This study investigates aspects of molar form in three African colobine species: Colobus polykomos, Colobus angolensis, and Piliocolobus badius. Our samples of C. polykomos and P. badius are from the Taï Forest, Ivory Coast; our sample of C. angolensis is from Diani, Kenya. To the extent that protective layers surrounding seeds are hard, we predicted that molar features related to hard-object feeding would be more pronounced in Colobus than they are Piliocolobus, as seed-eating generally occurs at higher frequencies in species of the former. We further predicted that among the colobines we studied, these features would be most pronounced in Taï Forest C. polykomos, which feeds on Pentaclethra macrophylla seeds encased within hard and tough seed pods. We compared overall enamel thickness, enamel thickness distribution, absolute crown strength, cusp tip geometry, and flare among molar samples. Sample sizes per species and molar type varied per comparison. We predicted differences in all variables except overall enamel thickness, which we expected would be invariant among colobines as a result of selection for thin enamel in these folivorous species. Of the variables we examined, only molar flare differed significantly between Colobus and Piliocolobus. Our findings suggest that molar flare, an ancient feature of cercopithecoid molars, was retained in Colobus but not in Piliocolobus, perhaps as a result of differences in the seed-eating proclivities of the two genera. Contrary to predictions, none of the aspects of molar form we investigated tracked current dietary differences in seed-eating between the two Colobus species. Finally, we explored the possibility that molar flare and absolute crown strength, when analyzed together, might afford greater differentiation among these colobine species. A multivariate t test of molar flare and absolute crown strength differentiated C. polykomos and P. badius, possibly reflecting known niche divergence between these two sympatric Taï Forest species.

Road Infrastructure and Primate Conservation: Introducing the Global Primate Roadkill Database.

As road infrastructure networks rapidly expand globally, especially in the tropics, previously continuous habitats are being fragmented, resulting in more frequent wildlife-vehicle collisions (WVC). Primates are widespread throughout many sub-/tropical countries, and as their habitats are fragmented, they are increasingly at risk of WVC. We created the Global Primate Roadkill Database (GPRD), the largest available standardized database of primate roadkill incidents. We obtained data from published papers, un-published and citizen science databases, anecdotal reports, news reports, and social media posts. Here, we describe the collection methods for the GPRD and present the most up-to-date version of the database in full. For each primate roadkill incident, we recorded the species killed, the exact location, and the year and month the roadkill was observed. At the time of publication, the GPRD includes 2862 individual primate roadkill records from 41 countries. As primates range in more than twice as many countries, the absence of data from these countries is not necessarily indicative of a lack of primate vehicular collisions. Given the value of these data for addressing both local and global research questions, we encourage conservationists and citizen scientists to contribute to the GPRD so that, together, we can better understand the impact road infrastructure has on primates and evaluate measures which may help mitigate risk-prone areas or species.

An effect of canopy bridges on monkey-vehicle collision hotspots: Spatial and spatiotemporal analyses.

Almost one-quarter of primate species are reported to be involved in vehicle collisions. To mitigate these collisions, canopy bridges are used though their effectiveness is not broadly substantiated. We studied bridge impact on 23 years of vehicle collisions (2000-2022: N = 765) with colobus (Colobus angolensis palliatus), Sykes' (Cercopithecus mitis albogularis), and vervet (Chlorocebus pygerythrus hilgerti) monkeys in Diani, Kenya. Along a 9 km road, collisions did not decrease over the study duration, although bridges increased from 8 to 30. Using the kernel density estimation plus (KDE+) method, collisions appeared highly concentrated at some locations. These concentrations, called hotspots, represent hazardous road segments, though the hotspots for all three species overlapped for only 3% of the road length. We then inspected the collision hotspots over time, using the spatiotemporal extension of the KDE+ method. We compared hotspot presence in the 3 years before and after bridge installation to determine if bridges mitigated these hotspots. Hotspots disappeared for ~60% of bridges postinstallation, suggesting that bridges effectively reduce some collisions. However, of the bridges installed in locations that were not hotspots, 13% had hotspots emerge. Surprisingly, regardless of preinstallation hotspot occurrence, almost one-fifth of bridges had postinstallation hotspots. To understand the extent to which bridges mitigate collisions, other factors need consideration, including species attributes and crossing behavior, and road features and vehicle volume. We used the novel analytical method because it best suited our data set, given the challenges of determining the bridge impact zone and the low collision frequency.

Mitochondrial genetic diversity and divergence dating of Angolan colobus monkeys (Colobus angolensis) in the eastern forests of Kenya and Tanzania: Implications for subspeciation and reconstructing historical biogeography.

Whether the Colobus angolensis that reside in the fragmented forests in eastern Kenya and Tanzania represent one subspecies or two has been debated for 50 years. Morphological and more recent genetic and ecological studies suggest that these populations represent two subspecies, C. a. palliatus and C. a. sharpei. However, their distribution of mitochondrial variation remains unresolved since the genetic study only characterized four populations at the range ends. Therefore, we characterized five populations in the area of the hypothesized subspecies divide. We identified eight new haplotypes which, combined with those previously identified, provided 26 haplotypes from nine populations for analysis. Haplotypes found south of the Rufiji River cluster together but separately from northern haplotypes. The largest sequence differences within cytochrome b occur between population pairs representing opposite sides of the river; their mean difference (1.5%) is more than that of other primate subspecies. Analysis of molecular variance attributes most of the variation to that north versus south of the river. These results support the previous subspecies distinction between C. a. palliatus (northern) and C. a. sharpei (southern), divided by the Rufiji River. The estimated time of the most recent common ancestor of all haplotypes indicates that the subspecies have been isolated from each other for approximately 550,000 years. The common ancestor of northern and southern haplogroups was 370,000 and 290,000 years ago, respectively. Nevertheless, the correlation between genetic and geographic distances suggests that isolation-by-distance contributed to population structuring. Significant variation among populations, with only three haplotypes shared between populations, also indicates that an extended period of isolation drove population distinctiveness. Considering these results, we evaluate hypotheses about the founding and differentiation of these subspecies during Pleistocene climatic fluctuations and propose a novel, more direct migration route from Central Africa to their current range navigating Lake Tanganyika, the central Tanzanian corridor, and the Rufiji River.

Differences between ecological niches in northern and southern populations of Angolan black and white colobus monkeys (Colobus angolensis palliatus and Colobus angolensis sharpei) throughout Kenya and Tanzania.

Ecological niche models can be useful for clarifying relationships between environmental factors and a species' geographic distribution. In this study, we use presence-only data and environmental layers to create an ecological niche model to better understand the distribution of the East African Angolan black and white colobus monkey, Colobus angolensis palliatus, and to assess whether the model supports considering the population as two separate subspecies, Colobus angolensis sharpei and C. a. palliatus. We found the range of the predicted distribution for suitable habitat of C. a. palliatus as currently classified to be only 12.4% of that shown in the International Union for Conservation of Nature Red List range map and to be fragmented. As C. angolensis is considered a "Least Concern" species, this difference suggests that generalized maps may lead to understating the species' extinction risk. When presence points were divided into two previously proposed subspecies -C. a. palliatus (Kenya and Northern Tanzania) and C. a. sharpei (Southern Tanzania)-we found significant environmental differences between the distributions. The most important ecological variable for C. a. palliatus was predominantly precipitation of the driest month (69.1%) whereas for C. a. sharpei annual precipitation (44.8%) and land cover (normalized difference vegetation index, 16.4%) were the most important. When comparing suitable ranges for the separate distributions, we found only a 1.2% geographical overlap. These differences are consistent with previous subspecies delineations of C. a. palliatus and C. a. sharpei based upon morphology, pelage, and genetics. Our study suggests that extirpation of C. a. palliatus in suitable habitat areas and occurrence of this subspecies in anthropogenic environments, warrant further consideration for conservation actions.

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.