Statutory protected areas and avian species richness in Britain

An effective portfolio of protected areas should, all else being equal, give rise to positive relationships between the amount of protected land in a region and the numbers of species present. Tests of this prediction are, however, extremely scarce, and most do not control for the potentially confounding effects of environmental factors that influence broad geographic trends in biodiversity. Here, we document the form of the relationship between species richness and coverage by protected areas using the British avifauna as a case study. We contrast relationships that arise for breeding and wintering assemblages, considering both all species collectively and threatened species only. We use spatially explicit multiple regression analyses that take into account environmental factors previously shown to exert a marked influence on avian species richness in Britain (temperature and altitude). Avian species richness and the amount of protected land are consistently positively correlated with each other, and the slopes of these relationships do not differ between assemblages (breeding/wintering and all species/threatened species). Explanatory power is, however, very weak which may be indicative of the ability of conservation measures in the wider landscape to maintain avian species richness, reducing any distinctive influence of protected areas. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Effects of hunting on guianan forest game birds

To assess the effect of on-going and of previous or near by hunting pressure on game birds in a neotropical rain forest (French Guiana), I compared species abundances between six hunted and disturbed areas, seven non-hunted and pristine areas and eight intermediate areas, undisturbed and not currently hunted, but formerly hunted or close to current hunting areas. I recorded all birds detected within 100 m-wide strip transects, walked at random through every forest type all day long. The frequency of records per 10 h and flock sizes on each transect were averaged over all surveys in each study site (N = 3025 h). Censused groups included terrestrial (tinamous, woodquails, curassow and trumpeter) and arboreal species (guans, macaws, parrots, toucans), but not waterbirds. The abundance of all game birds was higher in non-hunted than in hunted areas, though not always significantly for secretive understorey species (tinamous, guans, wood-quail) or canopy frugivores (parrots, macaws, toucans). The Black Curassow and Gray-winged Trumpeter exhibited the highest and most consistent increases (7–10-fold) and more so between intermediate and non-hunted sites than between hunted and intermediate sites. The mean flock size also increased along the hunting gradient, especially in flocking species (macaws, parrots, trumpeter). Low reproductive rates and/or seasonal movements may explain that hunting pressure could still be felt after hunting has ceased or when it persists only away from a given area. Such a persistent effect would affect some populations in small protected areas.     

Development of a scoring method to identify important areas of plant diversity in Ireland

In the face of accelerating biodiversity loss it is more important than ever to identify important areas of biodiversity and target limited resources for conservation. We developed a method to identify areas of important plant diversity using known species’ distributions and evaluations of the species importance. We collated distribution records of vascular plants and developed a scoring method of spatial prioritisation to assign conservation value to the island of Ireland at the hectad scale (10 km × 10 km) and at the tetrad scale (2 km × 2 km) for two counties where sufficient data were available. Each plant species was assigned a species conservation value based on both its conservation status and distribution in Ireland. For each cell, the species conservation values within the cell were summed, thereby differentiating between areas of high and low conservation value across the landscape. Areas with high conservation value represent the most important areas for plant conservation.The protected area cover and the number of species present in these important areas were also examined by first defining threshold values using two different criteria. Species representation was high in the important areas; the identified important areas of plant diversity maintained high representation of species of conservation concern and achieved high species representation overall, requiring a low number of sites (<8%) to do so. The coincidence of protected areas and important areas for plant diversity was found to be low and while some important areas of plant diversity might benefit from the general protection afforded by these areas, our research highlights the need for conservation outside of protected areas.     

Microhabitat associations and seedling bank dynamics in a neotropical forest

We conducted a rigorous test of tropical tree seedling microhabitat differentiation by examining microhabitat associations, survival and growth of established seedlings of ten tropical tree species representing a four-factor gradient in seed size. Eight microhabitat variables describing soil and light conditions were measured directly adjacent to each of 588 seedlings within twelve 10×100 m belt transects at Paracou, French Guiana, and at 264 reference points along the transects. From these measurements, we defined three principal components describing soil richness, soil softness and canopy openness. Six of ten species (in 9 of 30 total cases) were distributed non-randomly with respect to microhabitat along at least one principal component. However, few species demonstrated clear microhabitat specialization. All shifts in distribution relative to reference points were in the same direction (richer, softer soil). Furthermore, of 135 pairwise comparisons among the species, only 7 were significantly different. More than three-fourths of all seedlings (75.3%) survived over the 2-year monitoring period, but survival rates varied widely among species. In no case was the probability of survival influenced by any microhabitat parameter. Relative height growth rates for the seedlings over 2 years varied from –0.031 cm cm^–1 year^–1 (Dicorynia guianensis, Caesalpiniaceae) to 0.088 cm cm^–1 year^–1 (Virola michelii, Myristicaceae). In only 4 of 30 cases was height growth significantly associated with one of the three principal components. Because the conditions in this study were designed to maximize the chance of finding microhabitat differentiation among a group of species differing greatly in life history traits, the lack of microhabitat specialization it uncovered suggests that microhabitat partitioning among tropical tree species at the established seedling stage is unlikely to contribute greatly to coexistence among these species.     

The influence of soil cover organization on the floristic and structural heterogeneity of a Guianan rain forest

The impact of soil cover organization on the forest community has been studied in a 19-ha tract at Piste de St Elie station in French Guiana. 195 species each represented by at least 10 individuals were chosen from records of the position, diameter at breast height (dbh) and precise identification by botanical sampling of 12104 ligneous plants (dbh 10 cm).Spatial variations in the soil were mapped using the method proposed by Boulet et al. (1982). The soil mapping units correspond to the successive stages of evolution of a currently unbalanced ferralitic cover. These stages describe firstly the thinning by erosion of the microaggregated upper horizon and secondly the mineralogical changes under more or less extended hydromorphic conditions. The degree of evolution of ferralitic cover is also related to the hydrodynamic functioning and chemical properties of the soil. Geological substrate, topography and slope have also been taken into account.Analysis of the influence of environmental variables on plant cover has been performed using the Ecological Profiles method and Correspondence Analysis (CA) of the table of ecological profiles.The forest community seems to be dependent on the soil and the topographical features that govern it. There are significant, exclusive soil-species links for each soil functioning mapping unit. However, the highest proportion of significant positive links is connected with a thick microaggregated horizon (25%). Several species are of real value as indicators and more particularly enable differentiation between the forest stands of typical ferralitic soil and the ones of thinned out, transformed and hydromorphic soils. The CA of the species by environmental variables matrices reveals two significant factorial axes. The first can be associated with the drainage mainly related to the thinning of the soil and the second with the hydromorphic conditions related to the topography. The vegetation ordination of the stands ( 0.25 ha) delimited in the various soil domains clearly shows that changes in ferralitic cover and in particular the transition from soil with deep vertical drainage to soil with superficial lateral drainage is accompanied by substantial changes in the forest community.     

The unpredictability of favourability: condition assessment and protected areas in England

The probability that protected areas will deliver their potential for maintaining or enhancing biodiversity is likely to be maximised if they are appropriately and effectively managed. As a result, governments and conservation agencies are devoting much attention to the management of protected areas. In the U.K., the demand for performance accountability has resulted in Public Service Agreements (PSA) that set out targets for government departments to deliver results in return for investments being made. One such target for England is to ensure that all nationally important wildlife sites are in favourable condition by 2010. Here, we tested the hypothesis, of potential strategic importance, that the ecological condition of these sites is predictable from relationships with a range of physical, environmental and demographic variables. We used binary logistic regression to investigate these relationships, using the results of English Nature’s 1997–2003 condition assessment exercise. Generally, sites in unfavourable condition tend to be larger in area, located at higher elevations, but with higher human population density and are more spatially isolated from units of the same habitat. However, despite the range of different parameters included in our models, the extent to which the condition of any given site could be predicted was low. Our results have implications for the delivery of PSA targets, funding allocation, and the location of new protected areas.     

The influence of epiphyte cover on branch temperature in a tropical tree

The air temperature around three branches loaded with epiphytes in a tropical lowland rain forest in French Guiana was measured from mid-June to mid-July 1997. These data represent the first direct measurements of temperature close to epiphyte-loaded branches in a tropical lowland forest. The epiphytic biomass of one of the branches was removed after two weeks of measurements. These differences in stripped versus unstripped branch temperatures were positive during day time. A maximum difference of 4.8 °C was measured on a single sunny day; the maximum of four mid-day hours averaged over all days was 2.3 °C. Maxima were determined at locations close to the branch, representing high accumulations of humus, while nearly no differences were detected 75 cm away from the branch. At night, the temperature was cooler after epiphyte biomass removal; differences were up to –0.5 °C. Close to the branch, evaporation of stored water in humus cools the environment while latent heat transformation on epiphyte surfaces raises temperature. Shading under a branch prevents heating. Epiphytes reduce air circulation, keeping unheated air on branch undersides. At night, auto-heating of humus may occur through increased rates of respiration.     

The structure and status of forest fragments outside protected areas in central Uganda

Given the extent of tropical forest deforestation and as a number of conservation programmes and local communities rely on forest fragments, it has become important to understand how fragment exploitation by local communities affects forest structure and function. The effects of forest exploitation on forest structure and status of forest fragments were investigated in 20 nonreserved forest fragments in central Uganda. Enumeration of plots showed that tree species composition of the forest fragments was 60.0%, 23.7% and 6.3% for under‐storey, middle and top canopy trees respectively. The major activity was fuel wood extraction (65%), followed by brick making (10%), cultivation and livestock paddocks (10%), charcoal burning (5%), local brew distillation and others (5%). These extractive processes caused drastic structural changes, habitat degradation and destruction. Tree stumps enumeration indicated that under storey trees formed the highest proportion for wood extraction. There was no significant difference in the level of forest exploitation (basal area loss) among forest patches of varying sizes.     

Report on wind dispersal in a lowland moist forest in central French Guiana

An analysis of the flowering plant flora of a lowland moist forest in central French Guiana reveals 298 species with adaptations for wind dispersal. This represents 16.2% of the flowering plant flora and 9.8% of the class Magnoliopsida (dicotyledons). The most diverse wind-dispersed families are the Orchidaceae in the Liliopsida (monocotyledons) with 135 species and the Bignoniaceae in the Magnoliopsida with 37 species. The wind-dispersed species of central French Guiana have evolved either small, dust-like seeds, fruits or seeds with various kinds of wings, fruits or seeds with tufts of hairs, or expanded wing- or parachute-like persistent calyces. Most wind-dispersed species, among the liliopsids, are epiphytes and, among the magnoliopsids, trees or lianas. In central French Guiana, collections of these species with mature diaspores have been gathered most often in October and March, the months with peak wind velocities. In contrast, collections from June and July, when wind velocities are at a minimum, are rare.     

Early warning sign of forest loss in protected areas

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Patterns of frugivore species richness and abundance in forest islands and in agricultural habitats at Los Tuxtlas,Mexico

Destruction and fragmentation of tropical rain forest result in a loss of species and of generating capacity of the ecosystem via animal vectors such as seed dispersal agents. To gather quantitative data regarding this ecological problem, birds and mammals were censused in 30 forest fragments, 15 agricultural islands representing five types of vegetation (coffee, cacao, citrus, pepper and mixed-crops) and in three pastures in Los Tuxtlas, southern Veracruz, Mexico. More than 6000 animals of 257 species were detected thus suggesting the existence of a rich species pool in the fragmented landscape. Frugivores accounted for 60% of species, for 72% of individuals censured and for 85% of the total animal biomass recorded. Clusters of small forest fragments (<100 ha) were richer in species and individuals than clusters of large area (>100 ha) forest islands. Pastures were especially poor in forest birds and mammals. While the agricultural islands studied contributed to only 1% of the total area of vegetation sampled, they contained 58% of all species detected and 34% of all individual birds and mammals censured. Recaptures indicated inter-island movements of forest birds and mammals. Forty percent of the species were detected in forest habitats only, the rest were detected in forest and in agricultural habitats. Seeds of forest interior plants dispersed by birds and bats were detected in the agricultural habitats. The value of agricultural islands as landscape features providing some degree of biotic connectivity among fragmented animal populations is discussed.     

Residents’ attitudes toward three protected areas in southwestern Nepal

Understanding people’s beliefs and attitudes toward protected areas is a key factor in developing successful management plans to conserve those areas over the long-term. Yet, most of the emphasis in understanding people’s perceptions has been on the conflicts that exist between people and protected areas, such as loss of traditional extraction access or damage by wildlife to crops and livestock. This study addresses the need to explore people’s attitudes toward protected areas in a way that allows them to define and describe the values they hold toward the areas and the relevant issues and concepts. Three contrasting protected areas in the southwestern region of Nepal were chosen for this study to gain a broad representation of the values people hold toward different types of protected areas. Three themes emerged that describe the positive perceptions residents have: recreation/esthetics, environmental preservation, and economic benefits. Four themes emerged that describe the negative perceptions: negative economic impacts, belief that benefits are for the government or foreigners, fear of wildlife, and negative interactions with park guards. People’s perceptions are affected by different aspects of the areas, including the size of the area and people’s access to them, management objectives, history, and tourism. The diversity of these perceptions suggests that conservation strategies should recognize both positive and negative perceptions and work to foster and integrate diverse values in order to more accurately reflect the reality and complexity of people’s lives.     

Epizoochorous dispersal by barbs, hooks, and spines in a lowland moist forest in central French Guiana

An analysis of the flowering plant flora of a lowland moist forest in central French Guiana reveals 25 species with adaptations for epizoochorous dispersal by barbs, hooks, or spines (stick-tights). This represents 1.5% of the flowering plant flora. Stick-tights are represented among the monocotyledons of the flora of central French Guiana by five species of Poaceae. The Fabaceae and Asteraceae, each with six species with stick-tight dispersal, are the richest families of flowering plants in terms of stick-tight dispersal in central French Guiana. This region possesses numerous potential mammal and bird dispersal agents, therefore it is a puzzle why stick-tight dispersal, especially among species of the canopy, is not more frequent.     

Floristic composition across a climatic gradient in a neotropical lowland forest

Abstract. This study deals with the floristic composition of lowland tropical forest in the watershed of the Panama Canal. The floristic composition of large trees in 54 forest plots was analysed with respect to environmental factors, including precipitation, geologic parent material, stand age, topography, and soils. The plots contain 824 species of trees with a diameter at breast height ≥10 cm and represent a regional flora with exceptional β‐diversity. Plot data indicate that the Panamanian forest is strongly spatially structured at the landscape scale with floristic similarity decreasing rapidly as a function of inter‐plot geographic distance, especially for distances <5 km. The ordinations and patterns of endemism across the study area indicate broad floristic associations well correlated with Holdridge life zones. The results indicate the positive aspects of life zone classification at regional scales, while simultaneously highlighting its inadequacy for finer scales of analysis and resource management. Multivariate gradient analysis techniques (Non‐metric Multidimensional Distance Scaling and Detrended Correspondence Analysis) show clear patterns of floristic variability correlated with regional precipitation trends, surficial geology, and local soil attributes. Geologic and edaphic conditions, such as acidic soils or excessively drained limestone substrates, appear to override the effects of precipitation and modify forest composition. We conclude that the Panamanian forest shows clear patterns of spatial organization along environmental gradients, predominantly precipitation. The rapid decline in floristic similarity with distance between stands also suggests a role for dispersal limitation and stochastic events.     

Spatial distribution of primates in a mosaic of colonizing and old growth forest at Ngogo, Kibale National Park, Uganda

Primate censuses were conducted in a mosaic of colonizing (two locations) and old-growth forests using line transect methods at the Ngogo study site, Kibale National Park, Uganda. Black and white colobus monkeys (Colobus guereza) were encountered more frequently in the colonizing forests than in the old growth forest, while chimpanzees (Pan troglodytes) were encountered more frequently in the old growth forest than in colonizing forests. Although not significant, results suggest that blue monkeys (Cercopithecus mitis) frequented colonizing forests more often than old growth forest. The encounter rates of mangabey (Lophocebus albigena), and redtail (Cercopithecus ascanius) groups were ambiguous with their density being higher in some colonizing forests but not others as compared to old-growth forest. No significant differences were detected for baboons (Papio anubis), Lhoests (Cercopithecus lhoesti), and red colobus monkeys (Piliocolobus tephroscales). The conversion of forests to farmland is one of the major problems encountered in primate conservation. This study shows that secondary forests replacing anthropogenic grasslands have the potential of supporting some primate species such as black and white colobus, redtail monkeys, and possibly blue monkeys. Therefore, such areas should not be given up but should be conserved for the benefit of primates that can survive in secondary forests; as the forests mature further, primate species that are adapted to old growth forest will colonize the area provided there is a nearby source.     

Fruit choice by red howler monkeys (Alouatta seniculus) in a tropical rain forest

This paper presents and discusses aspects of fruit selectivity by red howler monkeys (Alouatta seniculus) in relation with morphological characteristics of fruits. These data are used to provide an answer to the following questions: which are the fruit characteristics that lead fruit choice of howler monkeys and to what extent fruit characteristics play a role in seed dispersal by monkeys? The frugivorous diet of a troop of red howler monkeys was determined during a 2-year field study in French Guiana. The selection of fruit by howler monkeys was analyzed in relation to the fruit availability. Results showed that, although consumption followed availability, fruit species could be classified in three categories according to their selection ratio (percentage of consumption/percentage of abundance) as “high ranking,” “middle ranking,” and “low ranking” species. Also, the 97 species of fruit eaten by the monkeys were grouped according to the morphological characteristics thought to influence the monkeys' choice. This showed that howler monkeys consumed essentially fruits with juicy pulp, bright color, and a small number of well-protected seeds. Most of high ranking species had medium-sized fruits with yellow color, and low ranking species often had small fruits. However, howler monkeys are associated with the dispersal of seeds from fruit with a hard and indehiscent pericarp and/or large seeds, like those of the Sapotaceae family. Consequently, they can be considered as “specialized” frugivores for this fruit syndrome. © l996 Wiley-Liss, Inc.     

Tree and shrub diversity and abundance in fragmented littoral forest of southeastern Madagascar

In the coastal littoral forest of extreme southeastern Madagascar, westudied tree diameter at breast height (DBH) 10 cm in 20, 50× 50 m plots in each of four forest fragments, andunderstorywoody vegetation (DBH < 10 cm, 1 m tall) in60,10 × 10 m plots in three of the fragments. Oneforestfragment was located in the highly degraded Lokaro region, and three in the nearbySainte-Luce forest. Atotal of 3476 trees, representing 169 species in 55 families, were recorded inthe50 × 50 m plots, and 10282 understory stems, representing195 species in 54 families, were found in the 10 × 10m plots. For each tree, DBH was recorded. Mean tree diameter andpatterns of tree size class distribution did not differ among the four forestfragments. However, the fragments differed significantly in both tree andunderstory stem densities, species richness and diversity values, and familyrichness values, with the Lokaro fragment having the lowest values for allmeasures. Furthermore, floristic patterns, family importance values, and communitysimilarity measures revealed that the species composition at theLokaro fragment was very different from the Sainte-Luce fragments. Anthropogenicdisturbance appears most pronounced in the isolated Lokaro forest, where bioticresources are limited to this single fragment.