Sophie Calmé

Nested bird and micro-habitat assemblages in a peatland archipelago

Abstract Biotic assemblages of insular habitats are nested when poor assemblages are subsets of richer ones. Nestedness of species assemblages is frequent and may result from selective extinction or frequent colonization in insular habitats. It may also be created by a nested distribution of habitats among islands or by sampling bias. We sampled 67 isolated peatlands (7–843 ha) in southern Quebec, Canada, to measure nestedness of bird species assemblages among peatlands and assess the habitat nestedness hypothesis. Species and microhabitat assemblages were both strongly nested among peatlands. Whether sites were ranked by species richness, microhabitat richness or peatland area had no effect on nestedness. However, microhabitat nestedness was significantly reduced when sites were sorted by area rather than by microhabitat richness. As expected, if bird-microhabitat associations are responsible for the nested pattern of distribution, we found a positive correlation between the contributions of bird species and microhabitats to individual site nestedness. Nevertheless, microhabitat assemblages were significantly less nested than bird species assemblages, possibly because of frequent recolonization by birds or uneven sampling among sites.

Soil preference and burrow structure of an endangered tarantula, Brachypelma vagans (Mygalomorphae: Theraphosidae)

Brachypelma vagans is an endangered tarantula included in Appendix II of CITES because of its popularity as a pet. However, little is known about its ecology, in particular microhabitat choices. In this work we analyse the structure of the vegetation surrounding burrows of this tarantula, as well as soil preference for the burrow at different sites in relation to the density of the species. We also offer the first description of the burrow of this spider. Brachypelma vagans mostly uses open sites with low vegetation for establishing its burrow, rather than primary or secondary forest. The burrows are essentially built in sites with deep clay soils, whereas sandy soils or soils with a high density of roots and stones are avoided. The soil characteristics may be the key factor determining the presence of B. vagans. The burrow of B. vagans is deep and complex, exhibiting various chambers, even if only one seems to be used by the occupant. The structure of the burrow and soil characteristics are obviously related. These results could help determine the real distribution of B. vagans within its geographic range, and might be useful for a better management focused on protection and reintroduction.

Applying evolutionary concepts to wildlife disease ecology and management.

Existing and emerging infectious diseases are among the most pressing global threats to biodiversity, food safety and human health. The complex interplay between host, pathogen and environment creates a challenge for conserving species, communities and ecosystem functions, while mediating the many known ecological and socio‐economic negative effects of disease. Despite the clear ecological and evolutionary contexts of host–pathogen dynamics, approaches to managing wildlife disease remain predominantly reactionary, focusing on surveillance and some attempts at eradication. A few exceptional studies have heeded recent calls for better integration of ecological concepts in the study and management of wildlife disease; however, evolutionary concepts remain underused. Applied evolution consists of four principles: evolutionary history, genetic and phenotypic variation, selection and eco‐evolutionary dynamics. In this article, we first update a classical framework for understanding wildlife disease to integrate better these principles. Within this framework, we explore the evolutionary implications of environment–disease interactions. Subsequently, we synthesize areas where applied evolution can be employed in wildlife disease management. Finally, we discuss some future directions and challenges. Here, we underscore that despite some evolutionary principles currently playing an important role in our understanding of disease in wild animals, considerable opportunities remain for fostering the practice of evolutionarily enlightened wildlife disease management.

Regional significance of peatlands for avifaunal diversity in southern Québec

Altough peatlands in southern Quebec are facing increasing pressure, neither specific nor substantial protection measures have been implemented, partly due to a lack of information on this ecosystem. We determined the contribution of peatlands to bird regional diversity by measuring the difference between peatland and associated regional avifaunas. We sampled 112 peatlands located along the Saint Lawrence River during one breeding season. We used data on regional nesting bird assemblages from the Quebec breeding bird atlas. Peatland bird species contrasted increasingly with regional avifauna from north to south or from undisturbed to managed landscapes. Of the 17 bird species found significantly more often in peatlands than in surroundings, some preferred peatlands in the whole study area and others preferred peatlands only in particular regions. Peatland avifaunas within regions were more similar to each other than to their regional avifauna, and differences between regions probably reflected changes in peatland physiognomy. We conclude that peatlands contribute to enrich local and regional avian diversity, particularly in the lowlands of the Saint Lawrence River, where industrial pressure on peatlands is highest. # 2002 Elsevier Science Ltd. All rights reserved.

Competing pressures on populations: long-term dynamics of food availability, food quality, disease, stress and animal abundance

Despite strong links between sociality and fitness that ultimately affect the size of animal populations, the particular social and ecological factors that lead to endangerment are not well understood. Here, we synthesize approximately 25 years of data and present new analyses that highlight dynamics in forest composition, food availability, the nutritional quality of food, disease, physiological stress and population size of endangered folivorous red colobus monkeys (Procolobus rufomitratus). There is a decline in the quality of leaves 15 and 30 years following two previous studies in an undisturbed area of forest. The consumption of a low-quality diet in one month was associated with higher glucocorticoid levels in the subsequent month and stress levels in groups living in degraded forest fragments where diet was poor was more than twice those in forest groups. In contrast, forest composition has changed and when red colobus food availability was weighted by the protein-to-fibre ratio, which we have shown positively predicts folivore biomass, there was an increase in the availability of high-quality trees. Despite these changing social and ecological factors, the abundance of red colobus has remained stable, possibly through a combination of increasing group size and behavioural flexibility.

A not so natural history of the tarantula Brachypelma vagans: Interaction with human activity

We describe the structure of a population of Brachypelma vagans (Ausserer, 1875) in relation to the intensity of human activity and report characteristics of the burrows in Campeche, Mexico. During September and October 2003, we established sampling areas in five different classes of vegetation type/land use: mature forest (MF), secondary forest (SF), backyard (BY), and a football field divided into corner area (FC) and goal area (FG). The densities of spiders and the proportion of different age/gender classes of individuals on the sites were compared. Morphological data among adults and juveniles were contrasted, and differences in morphology between juveniles were tested according to land use class. We compared the nearest distances between neighbouring burrows and between burrows and trees. Also, we studied the orientation of the burrows, and compared the diameter of the burrow entrance. Brachypelma vagans was found exclusively in the open areas with densities that ranked from 0.02 to 0.1 individuals per square metre, being among the highest ever reported for Theraphosidae. However, there was a negative relationship between density and intensity of human activity. The population of this tarantula shows segregation in occupation of space. Females occupied exclusively the backyards, whereas juveniles occupied sites according to their stage of development. The youngest juveniles occupied the backyards, while the pre‐adults occupied the football field. The distance between burrows was highly variable at all the sites. However it tended to be shorter in the backyards. The orientation of burrows was in all sites preferentially directed northwards. The diameter of the burrow entrances was a relatively good indicator of the sex and age of its occupier, and related almost directly to the dimension of the body. This study provides better knowledge of the structure of B. vagans populations in a human‐modified environment and gives new information on the natural history of these spiders.

Improving Conservation Outcomes with Insights from Local Experts and Bureaucracies

We describe conservation built on local expertise such that it constitutes a hybrid form of traditional and bureaucratic knowledge. Researchers regularly ask how local knowledge might be applied to programs linked to protected areas. By examining the production of conservation knowledge in southern Mexico, we assert local expertise is already central to conservation. However, bureaucratic norms and social identity differences between lay experts and conservation practitioners prevent the public valuing of traditional knowledge. We make this point by contrasting 2 examples. The first is a masters thesis survey of local experts regarding the biology of the King Vulture (Sarcoramphus papa) in which data collection took place in communities adjacent to the Calakmul Biosphere Reserve. The second is a workshop sponsored by the same reserve that instructed farmers on how to monitor endangered species, including the King Vulture. In both examples, conservation knowledge would not have existed without traditional knowledge. In both examples, this traditional knowledge is absent from scientific reporting. On the basis of these findings, we suggest conservation outcomes may be improved by recognizing the knowledge contributions local experts already make to conservation programming.

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.

When landscape modification is advantageous for protected species. The case of a synanthropic tarantula, Brachypelma vagans

Landscape fragmentation usually has a considerable effect on the genetic and demographic viability of most species because it reduces population size and increases isolation among populations. This situation provokes loss of genetic diversity and increased inbreeding that can lead to population or species extinctions. Some studies also show that landscape fragmentation may have no effect on or even positive consequences for species genetic diversity. The protected tarantula, Brachypelma vagans, exhibits a particular situation in the Mexican Caribbean, which has experienced high lowland and coastal fragmentation because of recent increases in agricultural, urban and touristic development. This modified landscape structure creates favorable conditions for establishment of B. vagans populations in rural settlements. Populations of this tarantula have high densities of individuals, principally females and juveniles, and gene dispersion is assumed by the rare males. Within this context, we studied the influence of natural and anthropogenic fragmentation on the genetic diversity of six B. vagans populations (five continental, one insular), together with their spatial organization. Our approach used seven inter simple sequence repeat markers, which are highly polymorphic markers. The 76 loci selected revealed high genetic variability for continental populations and a low, but not critical situation, for the insular population. We detected a good level of gene exchange among continental populations, and an evident and recent isolation of the island population. This species exhibits a metapopulation structure in the lowlands with numerous local populations where mature females exhibit high birth site fidelity. We conclude that this protected species does not exhibit characteristics to warrant its current conservation status, and we propose complete revision of the ecological and genetic situation for B. vagans in particular, and for all species within the genus Brachypelma in general.

Insect attraction by webs of Nephila clavipes (Araneae: Nephilidae)

Abstract Although well studied, the role of spider webs in attracting prey and the role of web ornaments remain open questions. We carried out a field study to determine whether webs of Nephila clavipes (Linnaeus 1767) attract insects. Nephila builds large orb-webs with debris-decoration that host kleptobiotic Argyrodes spiders. We studied the potential prey of Nephila with sticky traps placed in two similar linear plots. One plot contained 20 Nephila webs, and the other was cleared of Nephila webs. We measured the number and size of the insects caught in the traps. We compared the size of the trapped insects with prey caught by Nephila and gleaned by Argyrodes. In the plot with Nephila webs we collected 314 individuals versus 105 individuals in the plot without Nephila. Species of Diptera and Coleoptera were captured most frequently. Four saprophagous families, Phoridae and Sciaridae (both Diptera), Staphylinidae and Elateridae (both Coleoptera), were more abundant in the plot with Nephila webs. We show for the first time under natural conditions that prey attraction is most efficient for saprophagous insects, suggesting that the debris-decoration in Nephila webs attracts this guild. We also found that the size of some insects captured does not correspond to the range of prey consumed by Nephila, but to that of kleptobiotic Argyrodes spiders. We hypothesize that the debris-decoration may be used by Nephila as a strategy to limit food competition with Argyrodes.