Can small wildlife conservancies maintain genetically stable populations of large mammals? Evidence for increased genetic drift in geographically restricted populations of Cape buffalo in East Africa

The Cape buffalo (Syncerus caffer caffer) is one of the dominant and most widespread herbivores in sub‐Saharan Africa. High levels of genetic diversity and exceptionally low levels of population differentiation have been found in the Cape buffalo compared to other African savannah ungulates. Patterns of genetic variation reveal large effective population sizes and indicate that Cape buffalos have historically been interbreeding across considerable distances. Throughout much of its range, the Cape buffalo is now largely confined to protected areas due to habitat fragmentation and increasing human population densities, possibly resulting in genetic erosion. Ten buffalo populations in Kenya and Uganda were examined using seventeen microsatellite markers to assess the regional genetic structure and the effect of protected area size on measures of genetic diversity. Two nested levels of genetic structure were identified: a higher level partitioning populations into two clusters separated by the Victoria Nile and a lower level distinguishing seven genetic clusters, each defined by one or two study populations. Although relatively small geographic distances separate most of the study populations, the level of genetic differentiation found here is comparable to that among pan‐African populations. Overall, correlations between conservancy area and indices of genetic diversity suggest buffalo populations inhabiting small parks are showing signs of genetic erosion, stressing the need for more active management of such populations. Our findings raise concerns about the future of other African savannah ungulates with lower population sizes and inferior dispersal capabilities compared with the buffalo.     

Are fission–fusion dynamics consistent among populations? A large‐scale study with Cape buffalo

Fission–fusion dynamics allow animals to manage costs and benefits of group living by adjusting group size. The degree of intraspecific variation in fission–fusion dynamics across the geographical range is poorly known. During 2008–2016, 38 adult female Cape buffalo were equipped with GPS collars in three populations located in different protected areas (Gonarezhou National Park and Hwange National Park, Zimbabwe; Kruger National Park, South Africa) to investigate the patterns and environmental drivers of fission–fusion dynamics among populations. We estimated home range overlap and fission and fusion events between Cape buffalo dyads. We investigated the temporal dynamics of both events at daily and seasonal scales and examined the influence of habitat and distance to water on event location. Fission–fusion dynamics were generally consistent across populations: Fission and fusion periods lasted on average between less than one day and three days. However, we found seasonal differences in the underlying patterns of fission and fusion, which point out the likely influence of resource availability and distribution in time on group dynamics: During the wet season, Cape buffalo split and associated more frequently and were in the same or in a different subgroup for shorter periods. Cape buffalo subgroups were more likely to merge than to split in open areas located near water, but overall vegetation and distance to water were very poor predictors of where fission and fusion events occurred. This study is one of the first to quantify fission–fusion dynamics in a single species across several populations with a common methodology, thus robustly questioning the behavioral flexibility of fission–fusion dynamics among environments.     

Phylogeography of an Australian termite, Amitermes laurensis (Isoptera, Termitidae), with special reference to the variety of mound shapes

In northern Australia, the debris-feeding termite Amitermes laurensis builds tall, wedge-shaped mounds in the northern part of Cape York Peninsula and Arnhem Land, where their habitats are seasonally flooded, and small dome shaped mounds in the southeastern part of Cape York Peninsula, where their habitats are well-drained. Phylogeographic analyses were conducted in 238 individuals from 30 populations using the mitochondrial cytochrome oxidase II (COII) gene. DNA sequences of 50 haplotypes were used to construct NJ, MP and ML trees. Phylogenetic trees for 16 Amitermes species showed monophyly of A. laurensis and the variation of A. laurensis mounds did not strongly correspond to the intraspecific phylogeny. It was observed that mounds with the same shape were constructed by phylogenetically different groups under similar environmental conditions and different mounds shapes were built by phylogenetically closely related groups under the different environmental conditions. Thus, phylogenetically close groups of A. laurensis, in different habitats, may adapt to environmental conditions by constructing different mound shapes. We also investigated the phylogeographic structure of A. laurensis. The significant positive correlation between genetic and geographic distances indicated isolation by distance, reflecting restricted dispersal ability of alates. Although the overall genetic structure of A. laurensis showed isolation by distance, we also identified two exceptions: (i) secondary contacts of genetically divergent lineages in southern Cape York Peninsula, and (ii) low genetic differences between geographically separated populations of Cape York Peninsula and Arnhem Land. Therefore, the phylogeography of A. laurensis may reflect continuous gene flow restricted to short distances and past changes of gene flow associated with the fluctuation of environmental conditions accompanying the changing sea levels in the Quaternary.     

Population structure of African buffalo inferred from mtDNA sequences and microsatellite loci: high variation but low differentiation

The African buffalo ( Syncerus caffer ) is widespread throughout sub-Saharan Africa and is found in most major vegetation types, wherever permanent sources of water are available, making it physically able to disperse through a wide range of habitats. Despite this, the buffalo has been assumed to be strongly philopatric and to form large aggregations that remain within separate home ranges with little interchange between units, but the level of differentiation within the species is unknown. Genetic differences between populations were assessed using mitochondrial DNA (control region) sequence data and analysis of variation at six microsatellite loci among 11 localities in eastern and southern Africa. High levels of genetic variability were found, suggesting that reported severe population bottlenecks due to outbreak of rinderpest during the last century did not strongly reduce the genetic variability within the species. The high level of genetic variation within the species was found to be evenly distributed among populations and only at the continental level were we able to consistently detect significant differentiation, contrasting with the assumed philopatric behaviour of the buffalo. Results of mtDNA and microsatellite data were found to be congruent, disagreeing with the alleged male-biased dispersal. We propose that the observed pattern of the distribution of genetic variation between buffalo populations at the regional level can be caused by fragmentation of a previous panmictic population due to human activity, and at the continental level, reflects an effect of geographical distance between populations.     

Informing Disease Models with Temporal and Spatial Contact Structure among GPS-Collared Individuals in Wild Populations

Contacts between hosts are essential for transmission of many infectious agents. Understanding how contacts, and thus transmission rates, occur in space and time is critical to effectively responding to disease outbreaks in free-ranging animal populations. Contacts between animals in the wild are often difficult to observe or measure directly. Instead, one must infer contacts from metrics such as proximity in space and time. Our objective was to examine how contacts between white-tailed deer (Odocoileus virginianus) vary in space and among seasons. We used GPS movement data from 71 deer in central New York State to quantify potential direct contacts between deer and indirect overlap in space use across time and space. Daily probabilities of direct contact decreased from winter (0.05–0.14), to low levels post-parturition through summer (0.00–0.02), and increased during the rut to winter levels. The cumulative distribution for the spatial structure of direct and indirect contact probabilities around a hypothetical point of occurrence increased rapidly with distance for deer pairs separated by 1,000 m – 7,000 m. Ninety-five percent of the probabilities of direct contact occurred among deer pairs within 8,500 m of one another, and 99% within 10,900 m. Probabilities of indirect contact accumulated across greater spatial extents: 95% at 11,900 m and 99% at 49,000 m. Contacts were spatially consistent across seasons, indicating that although contact rates differ seasonally, they occur proportionally across similar landscape extents. Distributions of contact probabilities across space can inform management decisions for assessing risk and allocating resources in response.     

Phylogeography of the African buffalo based on mitochondrial and Y-chromosomal loci: Pleistocene origin and population expansion of the Cape buffalo subspecies

Population genetics and phylogeography of the African buffalo (Syncerus caffer) are inferred from genetic diversity at mitochondrial D-loop hypervariable region I sequences and a Y-chromosomal microsatellite. Three buffalo subspecies from different parts of Africa are included. Nucleotide diversity of the subspecies Cape buffalo at hypervariable region I is high, with little differentiation between populations. A mutation rate of 13-18% substitutions/million years is estimated for hypervariable region I. The nucleotide diversity indicates an estimated female effective population size of 17 000-32 000 individuals. Both mitochondrial and Y-chromosomal diversity are considerably higher in buffalo from central and southwestern Africa than in Cape buffalo, for which several explanations are hypothesized. There are several indications that there was a late middle to late Pleistocene population expansion in Cape buffalo. This also seems to be the period in which Cape buffalo evolved as a separate subspecies, according to the net sequence divergence with the other subspecies. These two observations are in agreement with the hypothesis of a rapid evolution of Cape buffalo based on fossil data. Additionally, there appears to have been a population expansion from eastern to southern Africa, which may be related to vegetation changes. However, as alternative explanations are also possible, further analyses with autosomal loci are needed.     

Where buffalo and cattle meet: modelling interspecific contact risk using cumulative resistant kernels

African buffalo the primary source of foot and mouth disease (FMD) infection for livestock in South Africa. Predicting the spatial drivers and patterns of buffalo–cattle contact risk is crucial for developing effective FMD mitigation strategies. Therefore, the goal of this study was to predict fine‐scale, seasonal contact risk between cattle and buffaloes straying into communal lands adjacent to Kruger National Park. This study provides the first application of the cumulative resistant kernel method to calculate contact risk between two species. We built resistance surfaces from resource utilization models of buffalo and cattle and calculated the intersection of resistant kernels of the two species. This revealed that the contact risk is influenced by seasonality, water sources and fence strength, and the magnitude of contact risk is largely driven by buffalo and cattle dispersal abilities. The probability of contact was higher in the dry season, with hotspots along a main river and the weakest parts of the perimeter fence. In the wet season, contact risk was more diffuse and less concentrated along the main river and near settlements. The new approach of intersecting cumulative resistant kernels of two species can produce quantitative predictive maps of animals’ contact risk and help identify potential hotspots of disease transmission.     

Variation of group size among African buffalo herds in a forest-savanna mosaic landscape

Documenting within species group size variation is important to completely understand social organization within species and to interpret variation among species. Here, I investigated group size of African buffalo Syncerus caffer over 2 years in a heterogeneous landscape. African buffalo use closed continuous forest and vast open savannas, and anecdotal observations suggest that habitat type influences their social structure. While the Cape buffalo Syncerus caffer caffer is well studied, few data exist for the forest-dwelling Syncerus caffer nanus . I observed forest buffalo at Lopé National Park, Gabon, and examined variation of group size. Eighteen forest buffalo herds used the study area with an estimated population of 342 individuals (∼5 buffalo km⁻²). The mean group size for the 18 herds was 12 ± 2 (range of means=3–24), considerably smaller than Cape buffalo herds. For eight radiocollared forest buffalo, the mean group size was stable, varying little with time of day, across seasons, or between savanna and marsh habitat. However, herd size varied widely across herds, from fewer than 10 individuals in the smallest herds to more than 20 buffalo in the largest. Large herd size is associated with home ranges that contain substantial areas of open habitat, and thus more food resources than forested habitats.     

The role of dispersal ability, climate and spatial separation in shaping biogeographical patterns of phylogenetically distant plant groups in seasonally dry Andean forests of Bolivia

Aim To assess biogeographical patterns of Acanthaceae, Bromeliaceae, Cactaceae and Pteridophyta in Bolivian Andean seasonally dry forest islands and to explain current floristic differences between these islands by means of extrinsic (precipitation, elevation) and intrinsic (dispersal ability) factors. Location Ten isolated and disjunct seasonally dry forest areas in the Bolivian Andes and the adjacent seasonal forest areas of the Chiquitanía and Chaco regions. Methods We collated species data from recently updated and revised taxonomic treatments and herbarium collections for Acanthaceae, Bromeliaceae, Cactaceae and Pteridophyta, constructed floristic distance matrices to estimate beta diversity at the study sites and subjected them to Mantel correlation analyses. Multiple regressions on distance matrices allowed us to test the influence of geographical distance and environmental (elevation and precipitation) differences on floristic differentiation. Results Acanthaceae and Bromeliaceae, and to a lesser extent Cactaceae, showed coincident biogeographical patterns and suggested the presence of two seasonally dry forest groups in Andean Bolivia: one including all small isolated northern dry valleys and another including all southern valleys with connections to the lowland seasonal forests of the Chiquitanía and the Chaco. Most of the variation in the floristic distance matrices in these plant groups, with seed dispersal typically restricted to short distances, was explained by spatial separation between habitat islands. In contrast, pteridophytes showed a different biogeographical pattern. Their floristic differences between sites were determined by the environmental variables. The anemochorous and spore‐based dispersal system of this plant group seems to be a highly effective mechanism allowing pteridophytes to easily reach even the isolated dry valleys in inter‐Andean Bolivia. Main conclusions Current biogeographical patterns in dry Andean habitat islands can provide insights into the factors that control the processes of community assembly. We show that differences in community composition of phylogenetically distant plant groups in the understorey of seasonally dry forest islands can be explained by a combination of the habitat characteristics where the group is present (either precipitation, elevation or both) and, more interestingly, by group specific dispersal limitation (as inferred by geographical distance between island habitats).     

Effect of age,pregnancy, and tuberculosis status on oocyte parameters in African buffalo

In the past decades, the African buffalo (Syncerus caffer) population has steadily declined; an estimated reduction of 31.2% over 3 generations has resulted in classifying it as near threatened by the International Union for Conservation of Nature. Therefore, the aim of this work was a preliminary evaluation of the size and number of ovarian follicles and oocyte quality and quantity in African buffaloes in relationship to age, tuberculosis, and pregnancy status to assess feasibility of in vitro embryo production (IVEP) as a tool for conservation and propagation of this species. The study occurred during the winter dry season (Jul–Aug) of 2018 within Huluhluwe-Imfolozi National Park in Kwa-Zulu Natal, South Africa during the routine culling procedures of African buffalo carried out at the park by the provincial authorities as means of disease management and population control. We obtained ovaries from 39 adults and 10 juveniles, and transported them to the field laboratory where we counted follicles, collected oocytes by aspiration and slicing, and classified oocytes according to their morphology. Adult animals had more small and medium follicles compared to juveniles (small: 14.5 ± 0.1 [SE] vs. 14.0 ± 0.1; medium: 4.6 ± 0.7 vs. 2.0 ± 1.3); however, juvenile animals had more cumulus-oocyte complexes (COCs). Pregnancy and tuberculosis status did not affect COC recovery rate and quality. The oocyte recovery rate is comparable to cattle and higher than in water buffalo (Bubalus bubalis). Therefore, our results suggest that IVEP could be an effective tool for conservation of valuable germplasm in African buffalo. The use of aspiration, using an 18-gauge needle and syringe, followed by slicing the ovary with a scalpel blade increased the recovery of suitable COCs (aspiration = 37.2 ± 3.02%; aspiration and slicing = 46.1 ± 3.02%), supporting the use of aspiration and slicing to optimize oocyte collection for conservation of African buffalo.     

Social encounter networks: characterizing Great Britain

A major goal of infectious disease epidemiology is to understand and predict the spread of infections within human populations, with the intention of better informing decisions regarding control and intervention. However, the development of fully mechanistic models of transmission requires a quantitative understanding of social interactions and collective properties of social networks. We performed a cross-sectional study of the social contacts on given days for more than 5000 respondents in England, Scotland and Wales, through postal and online survey methods. The survey was designed to elicit detailed and previously unreported measures of the immediate social network of participants relevant to infection spread. Here, we describe individual-level contact patterns, focusing on the range of heterogeneity observed and discuss the correlations between contact patterns and other socio-demographic factors. We find that the distribution of the number of contacts approximates a power-law distribution, but postulate that total contact time (which has a shorter-tailed distribution) is more epidemiologically relevant. We observe that children, public-sector and healthcare workers have the highest number of total contact hours and are therefore most likely to catch and transmit infectious disease. Our study also quantifies the transitive connections made between an individual''s contacts (or clustering); this is a key structural characteristic of social networks with important implications for disease transmission and control efficacy. Respondents'' networks exhibit high levels of clustering, which varies across social settings and increases with duration, frequency of contact and distance from home. Finally, we discuss the implications of these findings for the transmission and control of pathogens spread through close contact.     

Activity rhythm and the ranging of a solitary male mountain gorilla (Gorilla gorilla beringei)

To clarify the advantages of solitary life in gorilla males, a lone silverback mountain gorilla (Gorilla gorilla beringei) was studied for nine months in the natural habitat of the Virunga volcanoes. While the time budget for each activity and daily activity cycle were similar to those of groups, his daily journey distance and ranging patterns differed from those of groups. His movements were little influenced by the distribution and abundance of foods, which strongly influence the movements of groups. He notably increased his day journey distances when he encountered neighboring groups. He persistently followed the groups for days and went out of his usual range area. These encounters shifted his monthly range from his natal group's range to that of other groups. When the silverbacks of the encountered groups noticed his presence, they usually gave hoots and chest-beats and sometimes fought violently with him, while females and immatures did not show positive responses towards him. Lone males could have more chance to contact females and to lure them away from their groups than silverbacks within groups. The lone male stage, accompanied by frequent contacts with different groups, probably provides maturing males with useful knowledge of neighboring groups and areas.     

Seasonal variation in daily patterns of social contacts in the European badger Meles meles

Social interactions among hosts influence the persistence and spread of infectious pathogens. Daily and seasonal variation in the frequency and type of social interactions will play an important role in disease epidemiology and, alongside other factors, may have an influence on wider disease dynamics by causing seasonal forcing of infection, especially if the seasonal variation experienced by a population is considerable. We explored temporal variation in within‐group contacts in a high‐density population of European badgers Meles meles naturally infected with Mycobacterium bovis (the causative agent of bovine tuberculosis). Summer contacts were more likely and of longer duration during the daytime, while the frequency and duration of winter contacts did not differ between day and night. In spring and autumn, within‐group contacts peaked at dawn and dusk, corresponding with when they were of shortest duration with reduced potential for aerosol transmission of pathogens. Summer and winter could be critical for transmission of M. bovis in badgers, due to the high frequency and duration of contacts during resting periods, and we discuss the links between this result and empirical disease data. This study reveals clear seasonality in daily patterns of contact frequency and duration in species living in stable social groups, suggesting that changes in social contacts could drive seasonal forcing of infection in wildlife populations even when the number of individuals interacting remains similar.     

Mid‐Holocene decline in African buffalos inferred from Bayesian coalescent‐based analyses of microsatellites and mitochondrial DNA

Genetic studies concerned with the demographic history of wildlife species can help elucidate the role of climate change and other forces such as human activity in shaping patterns of divergence and distribution. The African buffalo (Syncerus caffer) declined dramatically during the rinderpest pandemic in the late 1800s, but little is known about the earlier demographic history of the species. We analysed genetic variation at 17 microsatellite loci and a 302‐bp fragment of the mitochondrial DNA control region to infer past demographic changes in buffalo populations from East Africa. Two Bayesian coalescent‐based methods as well as traditional bottleneck tests were applied to infer detailed dynamics in buffalo demographic history. No clear genetic signature of population declines related to the rinderpest pandemic could be detected. However, Bayesian coalescent modelling detected a strong signal of African buffalo population declines in the order of 75–98%, starting in the mid‐Holocene (approximately 3–7000 years ago). The signature of decline was remarkably consistent using two different coalescent‐based methods and two types of molecular markers. Exploratory analyses involving various prior assumptions did not seriously affect the magnitude or timing of the inferred population decline. Climate data show that tropical Africa experienced a pronounced transition to a drier climate approximately 4500 years ago, concurrent with the buffalo decline. We therefore propose that the mid‐Holocene aridification of East Africa caused a major decline in the effective population size of the buffalo, a species reliant on moist savannah habitat for its existence.     

Parasite species richness in carnivores: effects of host body mass, latitude, geographical range and population density

Aim  Comparative studies have revealed strong links between ecological factors and the number of parasite species harboured by different hosts, but studies of different taxonomic host groups have produced inconsistent results. As a step towards understanding the general patterns of parasite species richness, we present results from a new comprehensive data base of over 7000 host–parasite combinations representing 146 species of carnivores (Mammalia: Carnivora) and 980 species of parasites.
Methods  We used both phylogenetic and non-phylogenetic comparative methods while controlling for unequal sampling effort within a multivariate framework to ascertain the main determinants of parasite species richness in carnivores.
Results  We found that body mass, population density, geographical range size and distance from the equator are correlated with overall parasite species richness in fissiped carnivores. When parasites are classified by transmission mode, body mass and home range area are the main determinants of the richness of parasites spread by close contact between hosts, and population density, geographical range size and distance from the equator account for the diversity of parasites that are not dependent on close contact. For generalist parasites, population density, geographical range size and latitude are the primary predictors of parasite species richness. We found no significant ecological correlates for the richness of specialist or vector-borne parasites.
Main conclusions  Although we found that parasite species richness increases instead of decreases with distance from the equator, other comparative patterns in carnivores support previous findings in primates, suggesting that similar ecological factors operate in both these independent evolutionary lineages.     

Effects of low-density feeding on elk–fetus contact rates on Wyoming feedgrounds

High seroprevalance for Brucella abortus among elk on Wyoming feedgrounds suggests that supplemental feeding may influence parasite transmission and disease dynamics by altering the rate at which elk contact infectious materials in their environment. We used proximity loggers and video cameras to estimate rates of elk-to-fetus contact (the primary source of brucellosis transmission) during winter supplemental feeding. We compared contact rates during high-density and low-density (LD) feeding treatments that provided the same total amount of food distributed over different areas. Low-density feeding led to >70% reductions in total number of contacts and number of individuals contacting a fetus. Proximity loggers and video cameras provided similar estimates of elk–fetus contact rates. Elk contacted fetuses and random control points equally, suggesting that elk were not attracted to fetuses but encountered them incidentally while feeding. The modeled relationship between contact rate and disease prevalence is nonlinear and LD feeding may result in large reductions in brucellosis prevalence, but this depends on the amount of transmission that occurs on and off feedgrounds. © 2012 The Wildlife Society.     

Effects of Joint Space Use and Group Membership on Contact Rates Among White-Tailed Deer

Abstract: Establishment and spread of infectious diseases are controlled by the frequency of contacts among hosts. Although managers can estimate transmission coefficients from the relationship between disease prevalence and age or time, they may wish to quantify or compare contact rates before a disease is established or while it is at very low prevalence. Our objectives were to quantify direct and indirect contacts rates among white-tailed deer (Odocoileus virginianus) and to compare these measures of contact rate with simpler measures of joint space use. We deployed Global Positioning System (GPS) collars on 23 deer near Carbondale, Illinois, USA, from 2002 to 2005. We used location data from the GPS collars to measure pairwise rates of direct and indirect contact, based on a range of proximity criteria and time lags, as well as volume of intersection (VI) of kernel utilization distributions. We analyzed contact rates at a given distance criterion and time lag using mixed-model logistic regression. Direct contact rates increased with increasing VI and were higher in autumn—spring than in summer. After accounting for VI, the estimated odds of direct contact during autumn—spring periods were 5.0–22.1-fold greater (depending on the proximity criterion) for pairs of deer in the same social group than for between-group pairs, but for direct contacts during summer the within:between-group odds ratio did not differ significantly from 1. Indirect contact rates also increased with VI, but the effects of both season and pair-type were much smaller than for direct contacts and differed little as the time lag increased from 1–30 days. These results indicate that simple measures of joint space use are insufficient indices of direct contact because group membership can substantially increase contacts at a given level of joint space use. With indirect transmission, however, group membership had a much smaller influence after accounting for VI. Relationships between contact rates and season, VI, and pair-type were generally robust to changes in the proximity criterion defining a contact, and patterns of indirect contacts were affected little by the choice of time lag from 1–30 days. The use of GPS collars provides a framework for testing hypotheses about the form of contact networks among large mammals and comparing potential direct and indirect contact rates across gradients of ecological factors, such as population density or landscape configuration.     

Species assemblages of cyclopoid Copepoda from Mantecal,Venezuela

A 14 year monitoring of species composition and abundance of cyclopoid copepods throughout the rainy and dry seasons in a flooded savanna at Mantecal, Apure State, Venezuela, is presented. Two characteristic habitats within these water bodies were selected: the open center of small ponds free of emergent vegetation and the surrounding flooded grassland. In total, 13 species were registered, all of which appeared in the flooded grassland and 11 of which occurred in the open water. Ten species were common for the two habitats during the dry season. The highest abundance was found in flooded grassland during the dry season. Eight species showed abundances greater than 1.0 individual per liter in flooded grassland during both seasons; 3 and 7 species were this abundant in the open water during rainy and dry seasons, respectively. Mesocyclops meridianus and Microcyclops varicans were the most abundant species in both habitats and seasons, while Thermocyclops decipiens was the dominant species during rainy season in open water. Principal component analysis indicates that the important species were positively correlated between them (sharing habitat and season).     

Vertebrate responses to fruit production in Amazonian flooded and unflooded forests

We document patterns of fruit and vertebrate abundance within an extensive, virtually undisturbed mosaic of seasonally flooded (várzea and igapó) and unflooded (terra firme) forests of central Amazonia. Using phenological surveys and a standardised series of line-transect censuses we investigate the spatial and temporal patterns of immature and mature fruit availability and how this may affect patterns of habitat use by vertebrates in the landscape. All habitats showed marked peaks in fruiting activity, and vertebrate detection rates varied over time for most species both within and between forest types. Many arboreal and terrestrial vertebrates used both types of flooded forest on a seasonal basis, and fluctuations in the abundance of terrestrial species in várzea forest were correlated with fruit availability. Similarly, the abundance of arboreal seed predators such as buffy saki monkeys (Pithecia albicans) and macaws (Ara spp.) were closely linked with immature fruit availability in terra firme forest. We conclude that highly heterogeneous landscapes consisting of terra firme, várzea and igapó forest appear to play an important role in the dynamics of many vertebrate species in lowland Amazonia, but the extent to which different forest types are used is highly variable in both space and time.     

Microsatellite analysis of genetic diversity in African buffalo (Syncerus caffer) populations throughout Africa

Genetic diversity in nine African buffalo (Syncerus caffer) populations throughout Africa was analysed with 14 microsatellites to study the effects of rinderpest epidemics and habitat fragmentation during the 20th century. A gradient of declining expected heterozygosity was observed among populations in Save Valley Conservancy (Zimbabwe), and northern and southern Kruger National Park (South Africa). This was explained by a high mortality in northern Kruger National Park during the rinderpest pandemic at the end of the 19th century followed by recolonization from neighbouring populations, resulting in intermediate heterozygosity levels in northern Kruger National Park. In other populations expected heterozygosity was very high, indicating that rinderpest and recent habitat fragmentation had a limited effect on genetic diversity. From expected heterozygosity, estimates of long-term effective population size were derived. Migration rates among populations in eastern and southern Africa were very high, as shown by a weak isolation by distance and significant correlation in allele frequencies between populations. However, there were indications that dry habitats could limit migration. Genetic distances within buffalo in central Africa were relatively large, supporting their status as distinct subspecies. Finally, it was observed that the higher polymorphic microsatellites were less sensitive at detecting isolation by distance and differences in Ne, which may be a result of the high mutation pressure at these loci.