Rafael Reyna-Hurtado

Range-wide declines of a key Neotropical ecosystem architect, the Near Threatened white-lipped peccary Tayassu pecari

We report a range-wide status assessment of a key Neotropical ecosystem architect, the white-lipped peccary Tayassu pecari , categorized as Near Threatened on the IUCN Red List, using published information and unpublished data from 41 scientists in 15 range countries. We estimate that the white-lipped peccary has been extirpated in 21% of its historical range over the last 100 years, with reduced abundance and a low to medium probability of long-term survival in another 48% of its current range. We found major range declines in Argentina, Paraguay, southern Brazil, Colombia, Venezuela, north-east Brazil, Mexico and Costa Rica. This species is particularly at risk in more xeric ecosystems, especially the caatinga, cerrado and pampas. Hunting and habitat destruction are the most severe threats, although there are also unexplained sudden die-offs suggestive of disease. We evaluate our results in light of this species’ important interspecific interactions and its role as an ecosystem architect. One of our recommendations is that conservation efforts should focus on landscape conservation of large, continuous and ecologically intact areas containing a mosaic of different habitat types.

Going, Going, Gone: A 15-Year History of the Decline of Primates in Forest Fragments near Kibale National Park, Uganda

Given accelerating trends of deforestation and human population growth, immediate and innovative solutions to conserve biodiversity are sorely needed. Between 1995 and 2010, we regularly monitored the population size and structure of colobus monkey populations in the forest fragments outside of Kibale National Park, Uganda. Through this monitoring we assessed the monkeys’ gastrointestinal parasites and fecal cortisol levels. Over 15 years, we documented a rapid decline in the number of fragments that supported primates, largely as a result of tree removal. Fecal cortisol levels of primates found in the fragments were consistently higher than in populations found in the continuous forest of the national park. The fragment populations also harbored gastrointestinal parasites rarely found in the main forest and exchanged bacteria with nearby people and livestock at high rates, suggesting that fragmentation facilitates disease transmission. Fragments supported the fuelwood needs of an average of 32 people living immediately adjacent to the fragment, and partially supported families up to three farms away (~400 m, representing 576 people). Intensive fuelwood harvesting occurred when neighboring households engaged in brewing beer (an average of 9.6 % of the households), distilling gin (8.8 %), or producing charcoal (14.5 %). Our data suggest that the future of small and unprotected forest fragments is bleak; a scenario that is unfortunately typical outside protected areas in many tropical regions.

Assessing Habitat Fragmentation Effects on Primates: The Importance of Evaluating Questions at the Correct Scale

Forest-dwelling mammals such as primates could be particularly vulnerable to habitat fragmentation; however, the definition and quantification of fragmentation have varied considerably among studies. This has resulted in contradictions and thus results are difficult to interpret and compare. To encourage a consistent and more precise use of the term “habitat fragmentation,” we reviewed 100 fragmentation studies on primates to quantify how fragmentation effects are assessed. We advocate that habitat fragmentation is a landscape-scale process that involves both loss and the breaking apart of habitat. Hence, independently analyzing both effects is necessary to assess the effects of the breaking apart of habitat while controlling for habitat loss (fragmentation per se). This needs to be done through landscape-scale studies (that is, using landscapes as the independent unit of observation); however, fragmentation studies on primates are typically at the single fragment scale, often with a single continuous forest used for comparison. We suggest that primate responses at the fragment scale can vary dramatically in landscapes with different habitat amounts and configurations. In this review we provide clear and consistent terminology to help future studies to accurately assess the effects of fragmentation on primates and to help to form a body of literature where comparisons among studies are possible?

Hunting and the conservation of a social ungulate: the white-lipped peccary Tayassu pecari in Calakmul, Mexico

The white-lipped peccary Tayassu pecari is a social ungulate that forms the largest groups documented for any tropical forest ungulate species. Since the 1950s the species has become increasingly rare in Mesoamerica, and the more frequent reporting of smaller groups may be related to increased hunting pressure. Here we address the conservation status of this species in terms of its group size and structure, breeding season, population density, and relationship with hunting patterns in the Calakmul region of southern Mexico. Group sizes, age structure and breeding season were recorded in one large non-hunted site (Calakmul Biosphere Reserve) and four adjacent hunted sites. Population density was estimated in the Reserve and hunting patterns were recorded from three adjacent villages. Results indicate that hunting pressure affects peccary populations by reducing group size. White-lipped peccary groups were larger in the Reserve (median = 25) than in the hunted areas (median = 16) but groups were generally smaller than those reported in other forests. These smaller group sizes indicate conservation concern for this species in the Calakmul region. In addition, the estimated population (0.43 km 2 ) is one of the lowest reported for this species. Hunting occurs mainly in the dry season, which is the peak of the breeding season and when peccary groups visit water bodies, where they are more easily hunted.

Patch depletion behavior differs between sympatric folivorous primates

Food competition in group-living animals is commonly accepted as a critical determinant of foraging strategies and social organization. Here we examine food patch depletion behavior in a leaf-eating (folivorous) primate, the guereza (Colobus guereza). Snaith and Chapman (2005) studied the sympatric folivorous red colobus (Procolobus rufomitratus), which shares many food resources with the guereza. They determined that red colobus deplete the patches (feeding trees) they use, while we found contrary evidence for guerezas using the same methods. We found that the time guerezas spent feeding in a patch was affected by neither tree size, an indicator of food abundance, nor the size of the feeding group, an indicator of feeding competition. For their principal food item (young leaves), intake rate remained constant and coincided with a decrease in the distance moved to find food within a patch, implying that guerezas do not deplete patches. This points to a fundamental difference in the use of food by guerezas and red colobus, which may be linked to the large difference in their group sizes and/or to a disparity in their digestive physiologies. However, further analyses revealed that the number of feeders within a patch did not affect patch depletion patterns in either species, leaving the potential for a physiological basis as the most plausible explanation. Our research highlights the need for a more critical examination of folivorous primate feeding ecology and social behavior, as all folivorous primates are typically lumped into a single category in socioecological models, which may account for conflicting evidence in the literature.

Primates in Fragments 10 Years Later: Once and Future Goals

In 2010, the Food and Agriculture Organization of the United Nations (FAO) estimated that 16 million hectares of forest per year were lost globally in the 1990s (FAO 2010), and approximately 12.5 million hectares/year were lost in countries with primate populations, an area just smaller than Greece or the US State of Mississippi (Chapman and Peres 2001; Chapman and Gogarten 2012). In contrast, in the last decade (2000–2010), the rate of deforestation has decreased globally by approximately 5.2 million hectares/year, and reforestation and natural expansion of forests in some countries significantly reduced the net loss of forest (FAO 2010). This may be in part due to the lack of resonance in satellite imagery between secondary and primary forest regions, particularly in the tropics. Unfortunately, the increase in forested lands has principally affected temperate regions of Europe and eastern Asia (e.g., China, Japan), but deforestation of most tropical forests has continued steadily (e.g., annual loss: 0.5 % in Africa, 1.2 % in Mesoamerica, 0.5 % in South America, 0.4 % in southeastern Asia; FAO 2011).

Safeguarding biodiversity: what is perceived as working, according to the conservation community?

Dramatic increases in human populations and per capita consumption, climate change, overexploitation of marine and freshwater resources, and deforestation have caused a litany of negative consequences for biodiversity. Such doom-and-gloom scenarios are widely known, frequently cited and frankly depressing. Although accurate assessments of threats have clear value for intervention planning, we believe there is also a need to reflect on successes. Such reflection provides balance to negative scenarios and may shift attention towards constructive, positive action. Here we use a systematic evaluation of 90 success stories provided by conservation scientists and practitioners to explore the characteristics of the projects perceived as being associated with success. Success was deemed to have occurred for 19.4% of the projects simply because an event had occurred (e.g. a law was passed) and for 36.1% of projects quantitative data indicated success (e.g. censuses demonstrated population increase). However, for most projects (63.9%) there was no evaluation and success was defined by the subjective opinion of the respondent. Conservation community members viewed successful projects most often as those being long-term (88%), small in spatial scale (52%), with a relatively low budget (68%), and involving a protectionist approach alone or in combination with another approach. These results highlight the subjectivity of definitions of success in conservation but also the characteristics of conservation efforts that the conservation community perceives as indicative of success.

Searching in heterogeneous and limiting environments: foraging strategies of white-lipped peccaries (Tayassu pecari)

Abstract Searching for patchily distributed, highly localized, and seasonally variable resources in heterogeneous environments poses significant challenges for social species living in cohesive groups. Here, we studied the searching strategies of a highly social mammal, the white-lipped peccary (Tayassu pecari), in Calakmul Biosphere Reserve, Mexico. Calakmul Biosphere Reserve is a seasonal tropical forest where important resources, such as water and food, are patchy distributed and temporarily scarce. We attempted to determine what theoretical searching model best explained the movement patterns of groups of white-lipped peccaries, including short-tailed, long-tailed, and scale-free distributions. We found that the only distribution that was well supported by the data was a zero-inflated lognormal distribution; this implies a general pattern of normally short-range intensive searching with occasional long-distance directed movements taking the animals away from previously searched areas. We also found that groups concentrated foraging activities around sources of water during the dry season, behaving as central-place foragers while occasionally searching distant areas. We discuss the potential adaptive values of such behavioral strategies for social species living in highly heterogeneous environments.

Emergent group level navigation: An agent-based evaluation of movement patterns in a folivorous primate

The foraging activity of many organisms reveal strategic movement patterns, showing efficient use of spatially distributed resources. The underlying mechanisms behind these movement patterns, such as the use of spatial memory, are topics of considerable debate. To augment existing evidence of spatial memory use in primates, we generated movement patterns from simulated primate agents with simple sensory and behavioral capabilities. We developed agents representing various hypotheses of memory use, and compared the movement patterns of simulated groups to those of an observed group of red colobus monkeys (Procolobus rufomitratus), testing for: the effects of memory type (Euclidian or landmark based), amount of memory retention, and the effects of social rules in making foraging choices at the scale of the group (independent or leader led). Our results indicate that red colobus movement patterns fit best with simulated groups that have landmark based memory and a follow the leader foraging strategy. Comparisons between simulated agents revealed that social rules had the greatest impact on a group’s step length, whereas the type of memory had the highest impact on a group’s path tortuosity and cohesion. Using simulation studies as experimental trials to test theories of spatial memory use allows the development of insight into the behavioral mechanisms behind animal movement, developing case-specific results, as well as general results informing how changes to perception and behavior influence movement patterns.

Analysing small-scale aggregation in animal visits in space and time: the ST-BBD method

Movement behaviour plays an important role in many ecological interactions. As animals move through the environment, they generate movement patterns, which are a combined result of landscape characteristics and species-specific behaviour. Measuring these ranging patterns is being facilitated by technological advances in collection methods, such as GPS collars, that are capturing movement on finer spatial and temporal scales. We propose the use of a novel spatiotemporal analytical framework (ST-BBD), based on the beta-binomial distribution (BBD) model, to measure small-scale aggregation in animal movement data sets, including two simulated and three collected primate data sets. We use this approach to distinguish different habitat uses of three primate species (red colobus, Procolobus rufomitratus , black howler, Alouatta pigra , and spider monkey, Ateles geoffroyi ) and quantify their specific use of the landscape in space and in time, using a parameter of the BBD that measures the variation in sites visited on a landscape. We found that estimates of aggregation in habitat use were higher in the frugivorous spider monkey, compared to the more folivorous howler monkey, and that in the red colobus, aggregation in site visits was dependent on group size and food availability. Applications of this framework to animal movement data could be useful in understanding ecological systems where habitat use is an important factor, such as the relationships between hosts and parasites, or parent plants and seed dispersers.