• Habitat differentiation among three Nigeria–Cameroon chimpanzee (Pan troglodytes ellioti) populations

      Abwe, Ekwoge E.; Morgan, Bethan J.; Tchiengue, Barthelemy; Kentatchime, Fabrice; Doudja, Roger; Ketchen, Marcel E.; Teguia, Eric; Ambahe, Ruffin; Venditti, Dana M.; Mitchell, Matthew W.; et al. (2019)
      Ecological niche models (ENMs) are often used to predict species distribution patterns from datasets that describe abiotic and biotic factors at coarse spatial scales. Ground-truthing ENMs provide important information about how these factors relate to species-specific requirements at a scale that is biologically relevant for the species. Chimpanzees are territorial and have a predominantly frugivorous diet. The spatial and temporal variation in fruit availability for different chimpanzee populations is thus crucial, but rarely depicted in ENMs. The genetic and geographic distinction within Nigeria–Cameroon chimpanzee (Pan troglodytes ellioti) populations represents a unique opportunity to understand fine scale species-relevant ecological variation in relation to ENMs. In Cameroon, P. t. ellioti is composed of two genetically distinct populations that occupy different niches: rainforests in western Cameroon and forest–woodland–savanna mosaic (ecotone) in central Cameroon. We investigated habitat variation at three representative sites using chimpanzee-relevant environmental variables, including fruit availability, to assess how these variables distinguish these niches from one another. Contrary to the assumption of most ENM studies that intact forest is essential for the survival of chimpanzees, we hypothesized that the ecotone and human-modified habitats in Cameroon have sufficient resources to sustain large chimpanzee populations. Rainfall, and the diversity, density, and size of trees were higher at the rainforest. The ecotone had a higher density of terrestrial herbs and lianas. Fruit availability was higher at Ganga (ecotone) than at Bekob and Njuma. Seasonal variation in fruit availability was highest at Ganga, and periods of fruit scarcity were longer than at the rainforest sites. Introduced and secondary forest species linked with anthropogenic modification were common at Bekob, which reduced seasonality in fruit availability. Our findings highlight the value of incorporating fine scale species-relevant ecological data to create more realistic models, which have implications for local conservation planning efforts.
    • Habitat drives dispersal and survival of translocated juvenile desert tortoises

      Nafus, Melia G.; Esque, Todd C.; Averill-Murray, Roy C.; Nussear, Kenneth E.; Swaisgood, Ronald R. (2017)
      In spite of growing reliance on translocations in wildlife conservation, translocation efficacy remains inconsistent. One factor that can contribute to failed translocations is releasing animals into poor-quality or otherwise inadequate habitat. Here, we used a targeted approach to test the relationship of habitat features to post-translocation dispersal and survival of juvenile Mojave desert tortoises Gopherus agassizii. We selected three habitat characteristics – rodent burrows, substrate texture (prevalence and size of rocks) and washes (ephemeral river beds) – that are tied to desert tortoise ecology. At the point of release, we documented rodent burrow abundance, substrate texture and wash presence and analysed their relationship to the maximum dispersal. We also documented the relative use by each individual for each habitat characteristic and analysed their relationships with survival and fatal encounters with a predator in the first year after release. In general, the presence of refugia or other areas that enabled animals to avoid detection, such as burrows and substrate, decreased the overall mortality as well as predator-mediated mortality. The presence of washes and substrate that enhanced the tortoises’ ability to avoid detection also associated with the reduced dispersal away from the release site. These results indicate an important role for all three measured habitat characteristics in driving dispersal, survival or fatal encounters with a predator in the first year after translocation. Synthesis and applications. Resource managers using translocations as a conservation tool should prioritize acquiring data linking habitat to fitness. In particular, for species that depend on avoiding detection, refuges such as burrows and habitat that improved concealment had notable ability to improve the survival and dispersal. Our study on juvenile Mojave desert tortoises showed that refuge availability or the distributions of habitat appropriate for concealment are important considerations for identifying translocation sites for species highly dependent on crypsis, camouflage or other forms of habitat matching.
    • Habitat utilization of Roatán Spiny-tailed Iguanas (Ctenosaura oedirhina) and its implications for conservation

      Goode, A.B.C.; Pasachnik, Stesha A.; Maple, T.L.; Iverson, John B.; Grant, Tandora D.; Knapp, Charles R.; Pasachnik, Stesha A. (2016)
      ...With data gathered from use/availability surveys, resource selection functions can identify habitats and environmental variables associated with the presence of a species. Herein, we used these techniques to better understand the distribution of the Roatán Spiny-tailed Iguanas (Ctenosaura oedirhina), a narrow-range endemic on the island of Roatán, Honduras....
    • Hapalemur meridionalis. The IUCN Red List of Threatened Species 2020

      Donati, G; Balestri, M; Campera, M; Eppley, Timothy M. (2020)
      There is a suspected population reduction of greater than or equal to30% in this species over a three generation period. Causes of this reduction (which have not ceased) include continuing decline in area, extent and quality of habitat, and exploitation through hunting. Between 1999-2005 habitat loss in the Tsitongambarika Protected Area has been 1.74% per year (Andriamasimanana 2008). A population reduction of greater than or equal to 30% is also suspected to be met in the next 27 years (over a three generation time period) due to the same causes. These causes have not ceased, and will to a large extent not be easily reversible. Of note, it has been estimated that there will be a 21% reduction in the species' range from 2000 to 2080 due to climate change alone (Brown and Yoder 2015). Based on these premises, the species is listed as Vulnerable.
    • Harpy eagles (Harpia harpyja) nesting at Refugio Amazonas, Tambopata, Peru feed on abundant disturbance-tolerant species

      Bowler, Mark; Couceiro, Daniel; Martinez, Rocio; Orihuela, Gabriela; Shoobridge, Juan Diego; Nycander, Eduardo; de Miranda, Everton B. P.; Tobler, Mathias W. (2020)
      The harpy eagle (Harpia harpyja) is one of the main predators of arboreal mammals in the neotropics, affecting the ecology and behaviour these species. Knowledge of harpy eagle diets across their geographical range is patchy, the ability of harpy eagles to adapt to changing habitats is still open to question….
    • Health risks from lead-based ammunition in the environment

      Bellinger, David C.; Burger, Joanna; Cade, Tom J.; Cory-Slechta, Deborah A.; Finkelstein, Myra; Hu, Howard; Kosnett, Michael; Landrigan, Philip J.; Lanphear, Bruce; Pokras, Mark A.; et al. (2013)
      ...No rational deliberation about the use of lead-based ammunition can ignore the overwhelming evidence for the toxic effects of lead, or that the discharge of lead bullets and shot into the environment poses significant risks of lead exposure to humans and wildlife. Given the availability of non-lead ammunition for shooting and hunting (Thomas 2013), the use of lead-based ammunition that introduces lead into the environment can be reduced and eventually eliminated. This seems to be a reasonable and equitable action to protect the health of humans and wildlife....
    • Hearing sensitivity in context: Conservation implications for a highly vocal endangered species

      Owen, Megan A.; Keating, Jennifer L.; Denes, Samuel K.; Hawk, Kathy; Fiore, Angela; Thatcher, Julie; Becerra, Jennifer; Hall, Suzanne; Swaisgood, Ronald R. (2016)
      Hearing sensitivity is a fundamental determinant of a species’ vulnerability to anthropogenic noise, however little is known about the hearing capacities of most conservation dependent species. When audiometric data are integrated with other aspects of species’ acoustic ecology, life history, and characteristic habitat topography and soundscape, predictions can be made regarding probable vulnerability to the negative impacts of different types of anthropogenic noise. Here we used an adaptive psychoacoustic technique to measure hearing thresholds in the endangered giant panda; a species that uses acoustic communication to coordinate reproduction. Our results suggest that giant pandas have functional hearing into the ultrasonic range, with good sensitivity between 10.0 and 16.0 kHz, and best sensitivity measured at 12.5–14.0 kHz. We estimated the lower and upper limits of functional hearing as 0.10 and 70.0 kHz respectively. While these results suggest that panda hearing is similar to that of some other terrestrial carnivores, panda hearing thresholds above 14.0 kHz were significantly lower (i.e., more sensitive) than those of the polar bear, the only other bear species for which data are available. We discuss the implications of this divergence, as well as the relationship between hearing sensitivity and the spectral parameters of panda vocalizations. We suggest that these data, placed in context, can be used towards the development of a sensory-based model of noise disturbance for the species.
    • Hepatitis and splenitis due to systemic tetratrichomoniasis in an American white pelican (Pelecanus erythrorhynchos)

      Burns, Rachel E.; Braun, Josephine; Armién, Aníbal G.; Rideout, Bruce (2013)
      A free-ranging, young adult, female American white pelican (Pelecanus erythrorhynchos), found dead on the grounds of the San Diego Zoo Safari Park in Southern California, had severe multifocal to coalescing necrotizing hepatitis and splenitis on postmortem examination. Histologically, within the large areas of necrosis were myriad pleomorphic, 5–20 µm in diameter, protozoal organisms with 1 to multiple nuclei. Ultrastructurally, the organisms were consistent with a trichomonad flagellate. Polymerase chain reaction and sequencing of the small subunit ribosomal RNA gene identified nucleotide sequences with 99% identity to Tetratrichomonas gallinarum, which is a common inhabitant of the intestinal tract of galliform and anseriform birds that has occasionally been associated with disease, including typhlitis and hepatitis. Damage to the cecal mucosa in the pelican from trematodes and secondary bacterial infection could have allowed invasion and systemic dissemination of the organism. Exposure of the pelican to a variety of native and exotic anseriform and galliform birds at the zoological institution could have led to cross-species infection and severe manifestation of disease in a novel host.
    • Heterozygosity–Fitness Correlations Reveal Inbreeding Depression in Neonatal Body Size in a Critically Endangered Rock Iguana

      Moss, Jeanette B.; Gerber, Glenn P.; Welch, Mark E. (Oxford University Press (OUP), 2019)
      Inbreeding depression, though challenging to identify in nature, may play an important role in regulating the dynamics of small and isolated populations. Conversely, greater expression of genetic load can enhance opportunities for natural selection. Conditional expression concentrates these opportunities for selection and may lead to failure of detection. This study investigates the possibility for age-dependent expression of inbreeding depression in a critically endangered population of rock iguanas, Cyclura nubila caymanensis. We employ heterozygote-fitness correlations to examine the contributions of individual genetic factors to body size, a fitness-related trait. Nonsignificant reductions in homozygosity (up to 7%) were detected between neonates and individuals surviving past their first year, which may reflect natural absorption of inbreeding effects by this small, fecund population. The majority of variation in neonate body size was attributed to maternal or environmental effects (i.e., clutch identity and incubation length); however, heterozygosity across 22 microsatellite loci also contributed significantly and positively to model predictions. Conversely, effects of heterozygosity on fitness were not detectable when adults were examined, suggesting that inbreeding depression in body size may be age dependent in this taxon. Overall, these findings emphasize the importance of taking holistic, cross-generational approaches to genetic monitoring of endangered populations.
    • Hiding in plain sight: a study on camouflage and habitat selection in a slow-moving desert herbivore

      Nafus, Melia G.; Germano, Jennifer M.; Perry, Jeanette A.; Todd, Brian D.; Walsh, Allyson; Swaisgood, Ronald R. (2015)
    • Hierarchical dominance structure in reintroduced California condors: correlates, consequences, and dynamics

      Sheppard, James; Walenski, Matthew; Wallace, Michael P.; Vargas Velazco, J.J.; Porras, C.; Swaisgood, Ronald R. (2013)
      Populations of reintroduced California condors (Gymnogyps californianus) develop complex social structures and dynamics to maintain stable group cohesion, and birds that do not successfully integrate into group hierarchies have highly impaired survivability. Consequently, improved understanding of condor socioecology is needed to inform conservation management strategies…
    • High jaguar densities and large population sizes in the core habitat of the southwestern Amazon

      Tobler, Mathias W.; Carrillo-Percastegui, S.E.; Zúñiga Hartley, A.; Powell, G.V.N. (2013)
      Over 80% of the currently occupied range of the jaguar (Panthera onca) lies in the Amazon. However, few density estimates exist for this habitat. Between 2005 and 2010 we carried out six camera trap surveys at three different sites in the department of Madre de Dios in the Peruvian Amazon….
    • High-energy, high-fat lifestyle challenges an Arctic apex predator, the polar bear

      Pagano, Anthony M.; Durner, G. M.; Rode, K. D.; Atwood, T. C.; Atkinson, S. N.; Peacock, E.; Costa, D. P.; Owen, Megan A.; Williams, T. M. (2018)
      A demanding lifestyle Polar bears appear to be well adapted to the extreme conditions of their Arctic habitat. Pagano et al., however, show that the energy balance in this harsh environment is narrower than we might expect (see the Perspective by Whiteman). They monitored the behavior and metabolic rates of nine free-ranging polar bears over 2 years....
    • Highly polymorphic colour vision in a New World monkey with red facial skin, the bald uakari Cacajao calvus

      Corso, Josmael; Bowler, Mark; Heymann, Eckhard W.; Roos, Christian; Mundy, Nicholas I. (2016)
      Colour vision is highly variable in New World monkeys (NWMs). Evidence for the adaptive basis of colour vision in this group has largely centred on environmental features such as foraging benefits for differently coloured foods or predator detection, whereas selection on colour vision for sociosexual communication is an alternative hypothesis that has received little attention. The colour vision of uakaris (Cacajao) is of particular interest because these monkeys have the most dramatic red facial skin of any primate, as well as a unique fission/fusion social system and a specialist diet of seeds. Here, we investigate colour vision in a wild population of the bald uakari, C. calvus, by genotyping the X-linked opsin locus. We document the presence of a polymorphic colour vision system with an unprecedented number of functional alleles (six), including a novel allele with a predicted maximum spectral sensitivity of 555 nm. This supports the presence of strong balancing selection on different alleles at this locus. We consider different hypotheses to explain this selection. One possibility is that trichromacy functions in sexual selection, enabling females to choose high-quality males on the basis of red facial coloration. In support of this, there is some evidence that health affects facial coloration in uakaris, as well as a high prevalence of blood-borne parasitism in wild uakari populations. Alternatively, the low proportion of heterozygous female trichromats in the population may indicate selection on different dichromatic phenotypes, which might be related to cryptic food coloration. We have uncovered unexpected diversity in the last major lineage of NWMs to be assayed for colour vision, which will provide an interesting system to dissect adaptation of polymorphic trichromacy.
    • Histopathologic findings in free-ranging California hummingbirds, 1996–2017

      Magagna, Michelle; Noland, Erica; Tell, Lisa A.; Purdin, Guthrum; Rideout, Bruce; Lipman, Max W.; Agnew, Dalen (2018)
      A histopathologic study of free-ranging hummingbirds in California was performed to identify mortality trends. Tissues from 61 wild hummingbirds representing five native California species collected by the San Diego Zoo from 1996 to 2016 or the Lindsay Wildlife Experience from 2015 to 2017 were histologically examined....
    • Historical and geographical patterns in Knemidocoptes mite infestations in Southern California birds

      Clark, Kevin B.; Rideout, Bruce; Garrett, Kimball L.; Unitt, Philip; O’Connor, Barry (2019)
      We investigated the causes of toe and foot loss and other deformities long observed in urban Brewer’s Blackbirds (Euphagus cyanocephalus) in southern California. Histopathologic evaluation showed that afflicted individuals suffered from infestations of mites compatible with Knemidokoptes spp. (scaly-leg mites). We developed a case definition based on gross lesions in confirmed cases and the scientific literature to search two large ornithological collections for specimens exhibiting these lesions. In evaluating specimens among seven species of the family Icteridae, we found 34 specimens in the two collections with lesions consistent with Knemidokoptes spp. Species afflicted included the Red-winged Blackbird (Agelaius phoeniceus; 12 of 978 specimens), Brewer’s Blackbird (10/337 specimens), Tricolored Blackbird (A. tricolor; 4/101 specimens), Brown-headed Cowbird (Molothrus ater; 4/828 specimens), and Great-tailed Grackle (Quiscalus mexicanus; 4/224 specimens). The earliest cluster of California specimens dated to 1962. Fourteen of the 34 specimens exhibiting the condition were collected since 1999. No specimens of the Yellow-headed Blackbird (Xanthocephalus xanthocephalus; 0 of 214 specimens) or Western Meadowlark (Sturnella neglecta; 0/278) were found with the condition.
    • Hologenomic adaptations underlying the evolution of sanguivory in the common vampire bat

      Mendoza, M. Lisandra Zepeda; Xiong, Zijun; Escalera-Zamudio, Marina; Runge, Anne Kathrine; Thézé, Julien; Streicker, Daniel; Frank, Hannah K.; Loza-Rubio, Elizabeth; Liu, Shengmao; Ryder, Oliver A.; et al. (2018)
      The common vampire bat (Desmodus rotundus) is one of only three obligate blood-feeding mammals. By sequencing both its genome and gut metagenome, the authors provide a holistic view of the evolutionary adaptations that underlie this unusual diet.
    • Hopping over red leg: The metamorphosis of amphibian pathology

      Pessier, Allan P. (2017)
      It wasn’t very long ago that the only disease of amphibians that students might hear about in veterinary school was “red leg syndrome,” attributed to infections with the bacterium Aeromonas hydrophila.... This would begin to change with recognition of the “Amphibian Extinction Crisis.” ....
    • Hot monkey, cold reality: surveying rainforest canopy mammals using drone-mounted thermal infrared sensors

      Kays, Roland; Sheppard, James; Mclean, Kevin; Welch, Charlie; Paunescu, Cris; Wang, Victor; Kravit, Greg; Crofoot, Meg (2018)
      Animals of the rainforest canopies are often endangered by deforestation or hunting but are difficult to survey and study because of the inaccessibility of the treetops, combined with the visual camouflage of many species. Drone-based thermal sensors have the potential to overcome these hurdles by rapidly scanning large forested areas from above, detecting and mapping wildlife based on the contrast between their warm body temperatures and the cool tree canopies....
    • Human impact erodes chimpanzee behavioral diversity

      Kühl, Hjalmar S.; Boesch, Christophe; Kulik, Lars; Haas, Fabian; Arandjelovic, Mimi; Dieguez, Paula; Bocksberger, Gaëlle; McElreath, Mary Brooke; Agbor, Anthony; Angedakin, Samuel; et al. (2019)
      Chimpanzees possess a large number of behavioral and cultural traits among non-human species. The ‘disturbance hypothesis’ predicts that human impact depletes resources and disrupts social learning processes necessary for behavioral and cultural transmission....