<p>The threats of human encroachment and climate change are increasing and understanding the interplay between genetic diversity, fitness, and ecological variation has become critical for predicting adaptive responses and species extinction risk. Decreasing genetic diversity, owing to population decline or inbreeding, can be detrimental at the level of the individual, population, or species. One of the major challenges for evolutionary and conservation biologists is identifying the specific genetic components that influence inter-individual variation in fitness remains. As a direct link between genetic-make up and individual fitness, the Major Histocompatibility Complex (MHC) is critical to the activation of the adaptive immune system. Biologist have suggested that in addition to influencing an individual's health, variation at the MHC may be related to an individual's survival and reproductive success. Here, I test this hypothesis using two populations of ring-tailed lemurs (<italic>Lemur catta</italic>) at long-term study sites to achieve individual and population-level comparisons of MHC diversity and to integrate new genetic technology with behavioral, ecological, and environmental data. First, I address the difficulty of genotyping large populations at hypervariable genes by using next generation sequencing and suggest improvements to current methods. Second, I describe patterns of variation at the MHC-DRB 2nd exon, including diversity between alleles, individuals, and populations. Next, I examine the relationship between MHC-DRB diversity and measures of immunocompetence, parasitism, and survival within a broader framework of ecological variability across captive and wild conditions. Because the MHC is also thought to be important in mate choice and reproduction, I use an experimental approach in captive individuals to investigate possible mechanisms of MHC-based signaling through olfactory communication. Lastly, I link a female's MHC genotype to her reproductive success in the wild and explore if this relationship is altered by environmental stressors. The results of this dissertation emphasize the increasing feasibility of using genetic approaches to investigate the fitness correlates of genetic diversity non-model systems. These advances are critical for future studies and the integration of behavioral, ecological, and genetic perspectives in semi-natural and wild environments.</p> / Dissertation

Global climate change and habitat fragmentation represent two of the greatest threats to biodiversity and ecological processes worldwide. It is predicted that anthropogenic induced climate change could represent a key factor for extinctions in the near future, considering that the Earth is set to become warmer than at any period in the past 40 million years. Habitat fragmentation and isolation pose a number of challenges for the fauna inhabiting degraded areas, including lack of dispersal opportunities leading to inbreeding resulting in a loss of genetic diversity, reduced reproductive fitness; increases in vulnerability to predation, hunting, and disease, and an inability to deal with or respond to environmental changes and/or disease. Madagascar, the fourth largest island in the world, is home to unprecedented levels of endemism, including over 100 species of lemur. The island has undergone a range of historical and contemporary landscape transformations, both natural and anthropogenic. These landscape transformations combined with additional human-induced disturbances, such as the illegal pet and bushmeat trades, have had devastating effects on the island’s extant primate populations. Thus, Madagascar’s lemurs have been deemed the most endangered group of mammals and now represent the highest primate conservation priority in the world. The ring-tailed lemur (Lemur catta) is endemic to the southern regions of the island and occupies an array of habitats. L. catta is known for its remarkable behavioral and ecological flexibility, which contributes to its ability to exist in a mostly fragmented landscape. While this species represents one of the most well studied Malagasy strepsirhines, there has been a paucity of research regarding the population and conservation genetics of this endangered species. The goal of my dissertation was to examine the influence of habitat fragmentation and isolation on the genetic diversity and population structuring of this flagship species in three populations living in the central highlands of Madagascar: Anja Reserve, Sakaviro, and Tsaranoro Valley. Non-invasive fecal samples from 30 individual lemurs were collected from three fragmented forests and genotyped at six polymorphic microsatellite loci. Population genetic analyses were examined via GenAlEx software and revealed a moderate level genetic diversity. Genetic differentiation (FST) among the three fragmented populations ranged from 0.05-0.11. These data suggest that the L. catta populations within south-central Madagascar have not yet lost significant genetic variation. To examine past and recent demographic declines or genetic bottlenecks, I employed three approaches, including mode-shift and M-Ratio tests, as well as a test to detect heterozygosity excess using three mutation models: the two-phase model (TPM), step-wise mutation model (SMM), and the infinite allele model (IAM). Results were equivocal depending on the test that was applied; however, a mode-shift was detected for Anja, signifying this population underwent a historical bottleneck. M-ratio tests revealed that all three populations suffered historical bottlenecks. A population bottleneck was indicated via heterozygosity excess under the IAM for both the Anja and Sakaviro populations. To understand the impact of natural (e.g., mountains) and anthropogenic disturbances (e.g., roads, habitat fragmentation) on male reproductive strategies (dispersal) and population structuring, I utilized both GenAlEx and STRUCTURE software. Population assignment analyses suffered from a likely ‘lack of signal’. Therefore, individuals were unable to be reliably assigned to their population of origin. Genetic population structure was ambiguous. These data suggest that that these three fragmented populations are not genetically differentiated enough for proper population assignment, or perhaps the sample is not robust enough for population assignment analyses to produce unequivocal results. My research represents the first population genetic data for ring-tailed lemurs within the central highlands, and thus, serves as a baseline for future investigations into the genetic health of these populations. These data support the suggestion that these three fragments represent areas in which concerted conservation efforts are necessary if genetic diversity is to be maintained and future demographic declines are to be prevented. My results are informative for the local community conservation associations working within south-central Madagascar and can now be applied to determine areas of conservation priority and where forest corridors will be the most beneficial for maintaining gene flow. The loss and fragmentation of habitat continues across Madagascar, including the central highlands; thus, all remaining L. catta populations should be considered a high conservation priority. If we are to safeguard the long-term viability of this species, continued conservation and research initiatives will be crucial. / Graduate / 0327 / 0369 / lemurgirl.clarke@gmail.com

Le comportement alimentaire des primates varie en fonction de la disponibilité des ressources donc des saisons, et du choix de l'animal, facteur lié à des paramètres individuels. Les aliments consommés sont choisis en fonction de leur chimie (présence de nutriments, de composés toxiques...), et c'est le système gustatif qui permet de faire le lien entre un primate et les aliments qu'il consomme. Les tannins, toxiques à forte dose, sont les composés secondaires des plantes les plus répandus. Le Lemur catta, primate emblématique de Madagascar y est confronté dans son milieu naturel. <br />L'étude de lémurs catta captifs, confrontés à des plantes de climat tempéré riches en tannins (chênes, saules, ronces) montre qu'ils consomment spontanément des tannins dont le goût est perçu comme répulsif (dès 0,1 g/L pour l'acide tannique, seuil déterminé par le « two-bottle test »). Les quantités de tannins consommés et la concentration en tannins du régime varient en fonction des saisons alors que la perception du goût de l'acide tannique ne varie pas. Par contre, les différences individuelles de consommation de tannins sont expliquées par les différences de perception gustative : les animaux les plus sensibles aux tannins en sont les plus gros consommateurs.<br />La consommation de terre observée quasi-quotidiennement (principalement le matin, souvent à jeun) est corrélée avec celle de plantes à tannins, la géophagie serait alors un moyen de protection utilisé par les lémurs catta, les argiles ayant la capacité d'adsorber les tannins. Les tannins condensés consommés pourraient jouer un rôle dans la diminution avec le temps du parasitisme des individus. La semi-liberté associée à un accès à des plantes variées apporte de nombreux avantages aux lémuriens captifs car elle leur permet de diversifier leur alimentation et d'avoir accès à certaines activités pratiquées par les lémuriens sauvages.

Habitat fragmentation potentiates biodiversity loss worldwide. Species preservation requires an integrated understanding of wildlife-habitat relationships; however, responses to habitat fragmentation may vary considerably as a function of the species ecological flexibility and the unique attributes of each fragment habitat. In this dissertation, I explore the behavioural and health ecology of an ecologically flexible primate, the ringtailed lemur (Lemur catta), occupying forest fragments in south-central Madagascar that differ in isolation, degree of anthropogenic pressure, and L. catta food resource structure. Anja Special Reserve is a 34 ha rocky-outcrop forest fragment that is highly isolated from other forests containing L. catta. L. catta in this reserve have access to abundant food and water resources year-round due to the introduction of non-native fruit trees and the construction of an artificial lake adjacent the reserve, which support a population density of L. catta (6.6 lemurs/ha) that is higher than at any other site in which the species has been studied. In comparison, the Tsaranoro Valley forest is a 53 ha rocky-outcrop forest fragment that is surrounded by a matrix of grassy savannah and a few anthropogenic crops. While land clearing is pronounced in the valley, a few fragments remain within range for L. catta dispersal. L. catta in this fragment have limited access to introduced or anthropogenic resources and the population density (1.13 lemurs/ha) is one-sixth that at Anja. During the late dry season of 2010 and mid- to late-wet season of 2011, I collected continuous time focal animal data to examine behavioural patterns related to habitat use (ranging, matrix use, terrestriality), activity budgets, and feeding ecology of L. catta in each fragment. In addition, I examined two health parameters, stress and endoparasitism, through the collection of fecal samples from focal individuals. I compared these variables between and within populations to examine the potential impacts of habitat fragmentation on an ecologically adaptable primate. L. catta at Anja depended on smaller home range areas and a focused diet consisting largely of introduced food resources, and correspondingly exhibited lower energy expenditure, while spending more time engaging in rest and social acitivities when compared with the Tsaranoro lemurs. In comparison, L. catta at Tsaranoro occupied large home ranges, traveled greater distances to forage in the matrix habitat surrounding the fragment, and exhibited a more broad-based dietary strategy that contained few introduced or anthropogenic resources. From a health perspective, L. catta at Anja exhibited higher stress levels throughout the study period, while L. catta at Tsaranoro exhibited a greater prevalence of endoparasites, which may be reflective of differences in the social pressures and ranging patterns of L. catta between the two fragments, respectively. These results illustrate differences in the quality of the habitats and the potential fitness consequences that the L. catta populations must cope with, with important implications regarding the long-term suitability of these fragments for sustaining these populations. Such information is integral when assessing the viability of wildlife populations in degraded landscapes and should be a primary consideration for wildlife managers in biodiversity conservation. / Graduate / 0327 / 0329 / denisegabrie@gmail.com

<p>This thesis employs a network perspective in studying ecosystems and natural resource management. It explores the structural characteristics of social and/or ecological networks and their implications on societies’ and ecosystems’ ability to adapt to change and to cope with disturbances while still maintaining essential functions and structures (i.e. resilience).</p><p>Paper I introduces terminology from the network sciences and puts these into the context of ecology and natural resource management. Paper II and III focus on habitat fragmentation and how it affects an agricultural landscape in southern Madagascar. Two ecosystem services were addressed: (1) crop pollination by bees, and (2) seed dispersal by ring-tailed lemurs. It is shown that the fraction of the studied landscape presently covered by both crop pollination and seed dispersal is surprisingly high, but that further removal of the smallest habitat patches in the study area could have a severe negative impact on the landscape’s capacity to support these ecosystem services.</p><p>In Papers IV and V, the network approach is used to study social networks and the impact they may have on the management of natural resources. In Paper IV it is found that social networks of low- to moderate link densities (among managers) significantly increase the probability for relatively high and stable utility returns whereas high link densities cause occasional large-scale ecological crises between periods of stable and excessively high utility returns. In Paper V, social networks of a rural fishing community in eastern Africa were analyzed. The results indicate that patterns of communication partly explain the distribution of ecological knowledge among villagers, and that gear type used by small-scale coastal fishermen strongly correlates with their patterns of communication. The results also show that groups most central in the network, and hence potentially most influential, are dominated by one type of fishermen.</p>

This thesis employs a network perspective in studying ecosystems and natural resource management. It explores the structural characteristics of social and/or ecological networks and their implications on societies’ and ecosystems’ ability to adapt to change and to cope with disturbances while still maintaining essential functions and structures (i.e. resilience). Paper I introduces terminology from the network sciences and puts these into the context of ecology and natural resource management. Paper II and III focus on habitat fragmentation and how it affects an agricultural landscape in southern Madagascar. Two ecosystem services were addressed: (1) crop pollination by bees, and (2) seed dispersal by ring-tailed lemurs. It is shown that the fraction of the studied landscape presently covered by both crop pollination and seed dispersal is surprisingly high, but that further removal of the smallest habitat patches in the study area could have a severe negative impact on the landscape’s capacity to support these ecosystem services. In Papers IV and V, the network approach is used to study social networks and the impact they may have on the management of natural resources. In Paper IV it is found that social networks of low- to moderate link densities (among managers) significantly increase the probability for relatively high and stable utility returns whereas high link densities cause occasional large-scale ecological crises between periods of stable and excessively high utility returns. In Paper V, social networks of a rural fishing community in eastern Africa were analyzed. The results indicate that patterns of communication partly explain the distribution of ecological knowledge among villagers, and that gear type used by small-scale coastal fishermen strongly correlates with their patterns of communication. The results also show that groups most central in the network, and hence potentially most influential, are dominated by one type of fishermen.

By studying how captive animals use outdoor space, we can determine which areas fulfill their biological and behavioral needs to improve enclosure design for animal welfare and visitor experience. The aim of the study was to determine the differential use of outdoor space in a mixed exhibit of captive ring-tailed lemurs (Lemur catta) and red ruffed lemurs (Varecia rubra), and to assess both the effect of adding environmental enrichment and possible visitor and meteorological effects on the lemurs’ use of space and behavior. For one month, five-minute interval scan sampling was used to record lemur location and behavior, as well as the meteorological conditions and presence of zoo visitors in the lemurs’ outdoor enclosure. That baseline was followed by four alternating two-week periods of food or structural enrichment, both with and without visitors. Enrichment increased the lemurs’ use of the enriched sectors, decreased resting, and increased locomotion. Structural enrichment increased their exploratory behaviors and stimulated arboreal locomotion. Both species preferred sunny and warm conditions for sunbathing and resting, while moving more around the enclosure in cooler and cloudier weather. The visitor effect on the lemurs’ use of space was weaker than the effects of enrichment and meteorological conditions. The availability of areas to hide and possible habituation to humans may have played a role in the reduced visitor effect. The results of the study showed inter-specific differences in the lemurs’ use of space and behavior and a complex combined effect of enrichment, visitor presence and meteorological conditions.