Forest fragmentation and edge effects impact body condition, fur condition and ectoparasite prevalence in a nocturnal lemur community.

Forest fragmentation and edge effects are two major threats to primate populations. Primates inhabiting fragmented landscapes must survive in a more degraded environment, often with lower food availability compared to continuous forests. Such conditions can have deleterious effects on animal physiological health, yet some primates thrive in these habitats. Here, we assessed how forest fragmentation and associated edge effects impact three different components of physiological health in a nocturnal primate community in the Sahamalaza-Iles Radama National Park, northwest Madagascar. Over two periods, 6 March 2019-30 October 2019 and 10 January 2022-17 May 2022, we collected data on body condition, fur condition scores and ectoparasite prevalence for 125 Mirza zaza, 51 Lepilemur sahamalaza, 27 Cheirogaleus medius and 22 Microcebus sambiranensis individuals, and we compared these metrics between core and edge areas of continuous forest and fragmented forest. Body condition scores for all species varied between areas, with a positive response to fragmentation and edge effects observed for M. zaza and L. sahamalaza and a negative response for C. medius and M. sambiranensis. Fur condition scores and ectoparasite prevalence were less variable, although M. zaza and L. sahamalaza had a significantly negative response to fragmentation and edge effects for these two variables. Interestingly, the impacts of fragmentation and edge effects on physiological health were variable-specific. Our results suggest that lemur physiological responses to fragmentation and edge effects are species-specific, and body condition, fur condition and ectoparasite prevalence are impacted in different ways between species. As other ecological factors, including food availability and inter/intraspecific competition, likely also influence physiological health, additional work is required to determine why certain aspects of lemur physiology are affected by environmental stressors while others remain unaffected. Although many nocturnal lemurs demonstrate resilience to fragmented and degraded habitats, urgent conservation action is needed to safeguard the survival of their forest habitats.

Effects of forest fragmentation on the dietary ecology and activity of a nocturnal lemur community in North West Madagascar.

Deforestation and habitat fragmentation is the primary threat to primate populations. The primates that live within degraded and anthropogenically disturbed habitats typical of fragmented landscapes have to cope with lower availability of resources in comparison to primates in continuous, undisturbed forests. While some species are sensitive to forest fragmentation, some evidence exists to suggest that primates can alter their behavior and adapt to such changes, which enables their survival in suboptimal habitat. In this study, we assessed how forest fragmentation and its associated edge-effects impact the feeding ecology and activity levels of a nocturnal primate community in the Sahamalaza-Iles Radama National Park, North West Madagascar. From March 06, 2019 to May 17, 2022, we collected data on tree and invertebrate phenology at our study site, and feeding ecology and activity for 159 lemur individuals from four species. Fruit and flower availability varied significantly between continuous and fragmented forest, and between forest core and edge areas, with continuous forest exhibiting higher continuous fruit and flower availability. Lemur feeding ecology varied significantly too, as the feeding niches of all four species were significantly different between continuous and fragmented forest and between core and edge areas. However, lemur activity levels were mostly consistent among all forest areas. The results of this study suggest that nocturnal lemurs are able to adapt their dietary ecology in response to the available food sources within their habitat. Due to this flexible ecology and dietary plasticity, the lemurs do not need to significantly alter their behavior in different environments to fulfill their dietary needs. While nocturnal lemurs demonstrate adaptability and flexibility to degraded habitat, it is unclear how far this plasticity will stretch considering that Madagascar's forests are still being cleared at an alarming rate. Urgent conservation action is therefore needed to ensure the future of lemur habitat.

RETROSPECTIVE REVIEW OF MORTALITY IN CAPTIVE PINK PIGEONS (NESOENAS MAYERI) HOUSED IN EUROPEAN COLLECTIONS: 1977-2018.

The Mauritian pink pigeon (Nesoenas mayeri) is vulnerable, with only 400 individuals remaining in the free-living population. A European captive population was established in 1977 and a European Endangered Species Program (EEP) in 1992. The EEP long-term management plan recommends integrating the EEP and free-living Mauritius populations through pigeon transfers. A retrospective mortality review of the captive population was performed as part of a disease risk assessment process and to inform infectious disease screening prior to exporting captive birds to Mauritius. Six hundred pink pigeons from 34 institutions died from 1977 to 2018. Each individual was categorized according to age at time of death. Records from 404 individuals were categorized according to cause of death. Neonatal mortality (39%) and juvenile mortality (10.8%) were most commonly caused by noninfectious diseases (52% and 54.4%, respectively), including parental neglect and failure to thrive in neonates and nutritional secondary hyperparathyroidism in juveniles. Trauma (43.1%) was the most common cause of mortality in adults, with significantly higher mortality in males from interspecific aggression and in females due to intraspecific aggression. Yersinia pseudotuberculosis, Mycobacterium avium, and Escherichia coli were the most common infectious causes of adult mortality, and E. coli was the most common infectious cause in neonates. The following infectious diseases were identified as priorities for pre-export disease risk analysis, though not all caused mortality: Y. pseudotuberculosis, M. avium, Trichomonas spp., Chlamydia psittaci, and Coccidia spp. Husbandry changes have been made over the years to mitigate many of the noninfectious causes of mortality. These include alterations to nest sites to reduce neonatal trauma and abandonment, ultraviolet light supplementation and diet optimization to reduce metabolic disorders, improving enclosure design to reduce impact trauma, allowing females rest periods during breeding season, and avoiding housing with certain species.

Range Extension and Behavioural Observations of the Recently Described Sheth's Dwarf Lemur (Cheirogaleus shethi).

Sheth's dwarf lemur, Cheirogaleus shethi, is a small, recently discovered nocturnal primate endemic to northern Madagascar. Unlike many other nocturnal lemurs, C. shethi lives sympatrically with morphologically similar species of its cryptic genus, making it difficult for biologists to determine its population density and distribution. Here, we present new data and observations of this species. During a series of rapid biodiversity assessments in the SAVA region of north-eastern Madagascar, we observed C. shethi in 10 different sites, 9 of which were not previously known to harbour C. shethi populations. More significantly, 2 of these sites, in Analamanara, were situated approximately 20 km south of the previously known southern extremity of this species' distribution. This represents a large increase in the previously limited geographic range of this species. Moreover, our relatively high encounter rates at these sites suggest that C. shethi population densities may be high. We also observed C. shethi in human-altered (e.g., vanilla plantations) and non-forest, savannah environments, suggesting that this species can tolerate disturbed habitats. Our findings therefore provide important additional information on the distribution of C. shethi populations and highlight the necessity of further study for the conservation of this species.