Jean-Marc Thiollay

Bio: Jean-Marc Thiollay is an academic researcher from Centre national de la recherche scientifique. The author has contributed to research in topics: Species richness & Habitat. The author has an hindex of 9, co-authored 11 publications receiving 1109 citations.

Influence of Selective Logging on Bird Species Diversity in a Guianan Rain Forest

Abstract: The composition and structure of the bird com- munity were investigated in French Guiana (northeastern Amazonia) I year and 10 years after selective logging and compared with bird community composition and structure in undisturbed primary forest A point-count method was used in which 937 0.25-ha sample quadrats were censused for 20 minutes each. Whereas logging removed little more than 3 trees/ha, 38% of the forest undergrowth was destroyed and a higher proportion of the canopy was opened or dam- aged. An overall 27-33% decrease of species richness, fre- quency, and abundance occurred after logging with a less marked decline of diversity and evenness indices, a substan- tial increase in the proportion of dominant species, and a 45% difference in species composition, weighed by fre- quency, between logged and undisturbed forest communi- ties. Forty-two percent of the species from the primary forest decreased sharply or disappeared after logging and only 34% increased or remained unchanged. Microhabitat selection was the main correlate of sensitivity to disturbance. Most affected by logging were species associated with the under- story of tall mature stands especially terrestrial species, members of mixed flocks, and solitary sallying insectivores, all of which decreased by 70% to over 90%. Most birds as- sociated with canopy, small gaps, and vine tangles declined by only 10-30%. Small frugivores and species associated with clearings or edges increased. Among other factors, phys-

The Role of Traditional Agroforests in the Conservation of Rain Forest Bird Diversity in Sumatra

Abstract: Bird community composition and structure were compared among three different types of traditionally managed agroforests and the nearby primary forests in southwestern Sumatra during the breeding season. The agroforests were dominated respectively by rubber tree (Hevea brasiliensis), damar (Shorea javanica), and durian (Durio zibethinus) and were managed for cash crops (latex, resin, fruits, spices, coffee and timber). Although planted on formerly clearfelled and cultivated areas, these agroforests were highly diversified and structurally complex. Species relative abundance was obtained in 112 random samples of 50 individuals within limited census areas. The species were classified according to size, main diet, and observed habitat use. Eighty-three percent of all the regional pool of resident species were recorded at least once (excluding aerial, nocturnal, and aquatic species). Species richness, diversity, and equitability were all significantly lower (12% to 62% less) in every agroforest than in the primary forest, and the coefficients of similarity between the natural and managed forest communities were low (0.43–0.55). Less than half the lowland primary forest species known from western Sumatra were recorded in at least one agroforest. Among the 216 species occurring in samples, 56% significantly decreased in or disappeared from agroforests, whereas only 22% appeared or increased. The species most affected by the conversion of primary forests were large frugivores and large insectivores of the canopy and low understory, or terrestrial interior forest specialists. Species thriving in agroforests were small frugivores, foliage insectivores, and nectarivores often originally associated with gaps. The factors affecting biodiversity in agroforests may involve reduced tree height, canopy foliage volume, vertical diversity of the vegetation structure, floristic richness, and associated variety of food resources. High hunting pressure may also be a factor. These multipurpose, traditionally managed agroforests still are a valuable compromise between conservation of tropical forest biodiversity and sustainable use of natural resources. They also function as buffer zones between densely populated and protected areas and are one of the most successful examples of silviculture of dipterocarps. Yet they are not equivalent to primary forests.

Structure, density and rarity in an Amazonian rainforest bird community

Abstract: A 100-ha quadrat of primary rainforest in French Guiana was ccnsused over two consecutive years by the mapping method, and a 24-ha core area was intensively mistnetted at the same time. More extensive surveys were conducted in successively larger areas including up to a large part of the forested interior of the country. From a total of 441 resident species found in the rainforest zone, 248 were regularly recorded within the 100-ha plot, 157 of which had mean densities of more than 1 pair km-2. The total estimated density of birds was at least 829 pairs km-2. Only two dominant species exceeded 20 pairs km-2, while 52% of all the species were represented by less than 2 pairs km-2. The distribution of body masses and niche characteristics among the bird community is given as well as the sample bias of the mistnet captures.Rare species were a key component of this primary rainforest community. Several patterns of rarity were described and no marked and constant relationships were found between rarity and body size, habitat, diet, foraging behaviour or social system. Among a wide set of environmental constraints, the population of each species may be limited by a different combination of factors. Habitat heterogeneity, low, irregular and seasonal food availability, interspecific competition or heavy predation pressure were prominent and likely causes of the low density of most species which in turn facilitated the high species richness.

Multi-species territoriality and dynamic of neotropical forest understorey bird flocks

Abstract: 1. Eleven contiguous mixed-species bird flocks, with colour-banded individuals, were monitored continuously during 3 years in a 132-ha study area of primary rainforest in French Guiana. 2. Flock members were divided into six categories according to their flocking propensity and occurrence: 10 core or permanent species and 56 regular, occasional or incidental species. Each core species was represented by a single breeding pair with their fledglings and extra ‘floaters’ (unmated subadults and adults). 3. Flock home ranges overlapped slightly, but were communally defended by all core species in areas of overlap. Their size varied from 3·2 to 14·3 ha and was inversely correlated with vegetation density, but not flock size or species composition. 4. Flock number, size and composition, as well as boundaries were highly stable between seasons and years. Each flock had a single permanent gathering site and bathing site in late afternoon, the latter sometimes shared by 2–3 flocks. 5. Core species produced 0·18–0·73 fledglings per pair per year, which stayed in their natal flock for 200 to over 421 days. Then, these individuals usually moved between two and six different flocks, sometimes for up to 3 years, before finding a mate and a flock where they could settle and breed. Once breeding, they probably remained for life in the same flock. The mean annual survival rate was at least 0·75. 6. This highly evolved and stable organization, associated with a low breeding success and high survival rate was a critical factor maintaining low species density, delayed reproduction and a proportion of floating individuals buffering population fluctuations. 7. These social groups with their multi-species territoriality and co-evolved roles of flock members were similar to those described elsewhere in South America. They seem to be a general phenomenon in neotropical lowland rainforests.

Effects of rain forest disturbance and fragmentation: comparative changes of the raptor community along natural and human‐made gradients in French Guiana

Abstract: A density index of every diurnal raptor species (Falconiformes) was obtained on 101 400 ha sample plots distributed among eight natural habitats and five man-made habitats arranged along gradients of increasing forest degradation and fragmentation. The most significant structural parameter affecting species distribution was the tall canopy forest cover. Species richness, diversity and density all decreased with this mature forest cover index. Individual species and overall community densities decreased along the deforestation gradient but the species richness was partly maintained by species turnover. Six groups of species were identified according to their natural habitat preferences. Their distribution along the deforestation gradient was correlated with their natural habitat selection pattern. Thus the community composition of each vegetation or landscape type was predictable. Fifty-six percent of the regional assemblage of species had their optimal density in the primary forest. A third of them were interior forest species highly sensitive to forest disturbance and opening. The other two-thirds were upper canopy, gap or edge species more tolerant to forest fragmentation. The last twenty-one species were associated with various coastal habitats, from dense forest patches to mangrove and savanna. Again, one third of them were strictly restricted to their specialized habitats while the last two-thirds colonized human-altered habitats and progressively replaced primary forest species with increasing deforestation. The maintenance of large areas of every natural habitat was essential for the conservation of (1) the whole population of a third of the total raptor diversity and (2) optimal and presumably potential source populations of most other species surviving in human-modified habitats.

The Theory of Island Biogeography

Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

Biotic homogenization: a few winners replacing many losers in the next mass extinction

Abstract: Human activities are not random in their negative and positive impacts on biotas. Emerging evidence shows that most species are declining as a result of human activities ('losers') and are being replaced by a much smaller number of expanding species that thrive in human-altered environments ('winners'). The result will be a more homogenized biosphere with lower diversity at regional and global scales. Recent data also indicate that the many losers and few winners tend to be non-randomly distributed among higher taxa and ecological groups, enhancing homogenization.

Southeast Asian biodiversity: an impending disaster

Abstract: Southeast Asia has the highest relative rate of deforestation of any major tropical region, and could lose three quarters of its original forests by 2100 and up to 42% of its biodiversity. Here, we report on the current state of its biota and highlight the primary drivers of the threat of extinction now faced by much of the unique and rich fauna and flora of the region. Furthermore, the known impacts on the biodiversity of Southeast Asia are likely to be just the tip of the iceberg, owing to the paucity of research data. The looming Southeast Asian biodiversity disaster demands immediate and definitive actions, yet such measures continue to be constrained by socioeconomic factors, including poverty and lack of infrastructure. Any realistic solution will need to involve a multidisciplinary strategy, including political, socioeconomic and scientific input, in which all major stakeholders (government, non-government, national and international organizations) must participate.

Pattern and Process in Macroecology

Abstract: © 2000 by Blackwell Science Ltd. All rights reserved. Issues of scale have become increasingly important to ecologists. This book addresses the structure of regional (large-scale) ecological assemblages or communities, and the influence this has at a local (small-scale) level. This macroecological perspective is essential for the broader study of ecology because the structure and function of local communities cannot be properly understood without reference to the region in which they are situated. The book reviews and synthesizes the issues of current importance in macroecology, providing a balanced summary of the field that will be useful for biologists at advanced undergraduate level and above. These general issues are illustrated by frequent reference to specific well-studied local and regional assemblages -- an approach that serves to relate the macroecological perspective (which is perhaps often difficult to comprehend) to the everyday experience of local sites. Macroecology is an expanding and dynamic discipline. The broad aim of the book is to promote an understanding of why it is such an important part of the wider program of research into ecology. Summarises the current macroecological literature. Provides numerous examples of key patterns. Explicitly links local and regional scale processes. Exploits detailed knowledge of one species assemblage to explore broad issues in the structuring of biodiversity.

Biodiversity Conservation in Traditional Coffee Systems of Mexico

Abstract: In Mexico, coffee is cultivated on the coastal slopes of the central and southern parts of the country in areas where two or more types of vegetation make contact. Based on management level and vegetational and structural complexity, it is possible to distinguish five main coffee production systems in Mexico: two kinds of traditional shaded agroforests (with native trees), one commercially oriented polyspecific shaded sys- tem, and two "modern" systems (shaded and unshaded monocultures). Traditional shaded coffee is cultivated principally by small-scale, community-based growers, most of whom belong to some indigenous culture group. Through an exhaustive review of the literature, we found that traditional shaded coffee plantations are important repositories of biological richness for groups such as trees and epiphytes, mammals, birds, rep- tiles, amphibians, and arthropods. We evaluated the conservation role of these traditional shaded systems by estimating the percentage of the whole coffee area under traditional management, by reviewing the ecologi- cal and geographical distribution of coffee areas in Mexico, and by connecting the geographical distribution of these coffee areas with recognized centers of species richness and endemism. The assesment revealed that in Mexico, coffee fields are located in a biogeographically and ecologically strategic elevational belt that is an area of overlap between the tropical and temperate elements and of contact among the four main types of Mexican forests. We also found that between 60% and 70% of these coffee areas are under traditional man- agement and that at least 14 of 155 priority regions selected by experts as having high numbers of species and endemics overlap with or are near traditional coffee-growing areas.