Biodiversity Hotspot (biodiversity + hotspot)

Distribution by Scientific Domains
Distribution within Life Sciences


Selected Abstracts


DIVERSIFICATION OF THE AFRICAN GENUS PROTEA (PROTEACEAE) IN THE CAPE BIODIVERSITY HOTSPOT AND BEYOND: EQUAL RATES IN DIFFERENT BIOMES

EVOLUTION, Issue 3 2010
Luis M. Valente
The Cape region of South Africa is a hotspot of flowering plant biodiversity. However, the reasons why levels of diversity and endemism are so high remain obscure. Here, we reconstructed phylogenetic relationships among species in the genus Protea, which has its center of species richness and endemism in the Cape, but also extends through tropical Africa as far as Eritrea and Angola. Contrary to previous views, the Cape is identified as the ancestral area for the radiation of the extant lineages: most species in subtropical and tropical Africa are derived from a single invasion of that region. Moreover, diversification rates have been similar within and outside the Cape region. Migration out of the Cape has opened up vast areas, but those lineages have not diversified as extensively at fine spatial scales as lineages in the Cape. Therefore, higher net rates of diversification do not explain the high diversity and endemism of Protea in the Cape. Instead, understanding why the Cape is so diverse requires an explanation for how Cape species are able to diverge and persist at such small spatial scales. [source]


The discordance of diversification: evolution in the tropical-montane frogs of the Eastern Arc Mountains of Tanzania

MOLECULAR ECOLOGY, Issue 18 2010
LUCINDA P. LAWSON
Abstract Species with similar geographical distribution patterns are often assumed to have a shared biogeographical history, an assumption that can be tested with a combination of molecular, spatial, and environmental data. This study investigates three lineages of Hyperolius frogs with concordant ranges within the Eastern Afromontane Biodiversity Hotspot to determine whether allopatric populations of co-distributed lineages shared a parallel biogeographical response to their shared paleoclimatic histories. The roles of refugial distributions, isolation, and climate cycles in shaping their histories are examined through Hierarchical Approximate Bayesian Computation, comparative phylogeography, and comparisons of current and past geographical distributions using ecological niche models. Results from these analyses show these three lineages to have independent evolutionary histories, which current spatial configurations of sparsely available habitat (montane wetlands) have moulded into convergent geographical ranges. In spite of independent phylogeographical histories, diversification events are temporally concentrated, implying that past vicariant events were significant at the generic level. This mixture of apparently disparate histories is likely due to quantifiably different patterns of expansion and retreat among species in response to past climate cycles. Combining climate modelling and phylogeographical data can reveal unrecognized complexities in the evolution of co-distributed taxa. [source]


Floristic diversity in fragmented Afromontane rainforests: Altitudinal variation and conservation importance

APPLIED VEGETATION SCIENCE, Issue 3 2010
Christine B. Schmitt
Abstract Question: How does the floristic diversity of Afromontane rainforests change along an altitudinal gradient? What are the implications for conservation planning in these strongly fragmented forest areas that form part of the Eastern Afromontane Biodiversity Hotspot? Location: Bonga, southwestern Ethiopia. Methods: Based on evidence from other montane forests, we hypothesized that altitude has an effect on the floristic diversity of Afromontane rainforests in southwestern Ethiopia. To test this hypothesis, detailed vegetation surveys were carried out in 62 study plots located in four relatively undisturbed forest fragments situated at altitudes between 1600 m and 2300 m. Floristic diversity was evaluated using a combination of multivariate statistical analyses and diversity indices. Results: Ordination and indicator species analyses showed gradual variations in floristic diversity along the altitudinal gradient with a pronounced shift in species composition at ca. 1830 m. Upper montane forest (>1830 m) is characterized by high fern diversity and indicator species that are Afromontane endemics. Lower montane forest (<1830 m) exhibits a greater diversity of tree species and a higher abundance of the flagship species Coffea arabica. Conclusions: Our results provide crucial ecological background information concerning the montane rainforests of Ethiopia, which have been poorly studied until now. We conclude that both forest types identified during this study need to be considered for conservation because of their particular species compositions. Owing to the high degree of forest fragmentation, conservation concepts should consider a multi-site approach with at least two protected areas at different altitudinal levels. [source]


Effects of Tea Plantations on Stream Invertebrates in a Global Biodiversity Hotspot in Africa

BIOTROPICA, Issue 4 2009
Olly van Biervliet
ABSTRACT Tropical stream ecosystems in montane forest watersheds are important centers of endemism and diversity and provide essential ecosystem services. These habitats are subject to a variety of stressors, including the conversion of adjacent terrestrial habitats from forest to agriculture, but the impacts of these anthropogenic effects are largely unknown because of the paucity of studies in these systems. In montane habitats in the wet tropics, large-scale cultivation of tea is common and can represent an important source of income at local and national scales. However, little is known about how tea cultivation impacts adjacent stream ecosystems. In this study, we examine stream macroinvertebrate assemblages in a biodiversity hotspot the East Usambara Mountains, Tanzania. Specifically, we compare diversity of macroinvertebrate assemblages found on cobbles in stream riffles in watersheds dominated by forest with those surrounded by tea cultivation. We found that streams surrounded by tea were characterized by significantly lower dissolved oxygen and had lower total estimated species richness and number of families. Furthermore, the richness of invertebrate taxa known to be sensitive to anthropogenic disturbance were substantially reduced in tea streams and general assemblage-level analysis shows significant differences in the composition of macroinvertebrate assemblages between tea and forested streams. Our results suggest that tea cultivation may reduce stream habitat quality and biodiversity in the East Usambaras. Further research is needed to evaluate the effects of tea cultivation on streams over longer times scales and to address methods for minimizing negative effects of agriculture on montane stream communities. [source]


Passive Restoration in Biodiversity Hotspots: Consequences for an Atlantic Rainforest Lizard Taxocene

BIOTROPICA, Issue 3 2010
Agustín Camacho Guerrero
ABSTRACT Long-term conservation in biodiversity hotspots depends on the recovery of communities in secondary forest fragments. In most cases, however, recovery strategies for these areas are based only on passive restoration. It is therefore necessary to determine the efficiency of such strategies. In this study, we assess the efficiency of passive restoration on a 567-ha 28-yr-old fragment of Atlantic Rainforest in Northeastern Brazil. We measured richness, composition, abundance and biomass of a lizard taxocene and also vegetation structure and availability of several microhabitat descriptors in 18 plots of this secondary forest. We then compared them with measures in 29 plots from two neighboring reference sites. Species richness, abundance, biomass and microhabitat descriptors availability inside the secondary fragment did not differ from reference sites. However, composition and vegetation structure showed small differences. Some forest specialist lizards, which should be a focus of conservation efforts in fragmented landscapes of the Atlantic Rainforest, were not found in the fragment and data indicate that this was not due to sampling or a lack of suitable habitat or microhabitat. In the presence of preserved source sites, passive restoration may be a cheap and effective way to recover lizard taxocenes of the Atlantic Rainforest. Some of the species may need to be re-introduced to accelerate the full recovery of original composition of lizard taxocenes in secondary Atlantic Rainforests. Abstract in Portuguese is available at http://www.blackwell-synergy.com/loi/btp [source]


Biodiversity hotspots, centres of endemicity, and the conservation of coral reefs

ECOLOGY LETTERS, Issue 6 2002
Terry P. Hughes
Abstract On land, biodiversity hotspots typically arise from concentrations of small-range endemics. For Indo-Pacific corals and reef fishes, however, centres of high species richness and centres of high endemicity are not concordant. Moreover ranges are not, on average, smaller inside the Central Indo-Pacific (CI-P) biodiversity hotspot. The disparity between richness and endemicity arises because corals and reef fishes have strongly skewed range distributions, with many species being very widespread. Consequently, the largest ranges overlap to generate peaks in species richness near the equator and the CI-P biodiversity hotspot, with only minor contributions from endemics. Furthermore, we find no relationship between the number of coral vs. fish endemics at locations throughout the Indo-Pacific, even though total richness of the two groups is strongly correlated. The spatial separation of centres of endemicity and biodiversity hotspots in these taxa calls for a two-pronged management strategy to address conservation needs. [source]


Assessing priority areas by imperilled species: insights from the European butterflies

ANIMAL CONSERVATION, Issue 4 2009
S. Fattorini
Abstract Biodiversity hotspots have been variously defined in terms of species richness, endemic species or imperilled species. The use of imperilled species to locate priority areas is particularly problematic, because an area that hosts a large number of imperilled species is likely to be under severe threats, making less effective conservation efforts. A possibly way to answer this problem is to assess species threats at two spatial scales. Then, areas which host concentrations of species that are imperilled at the larger scale, but not at the smaller scale, can be considered as priority areas where conservation efforts are expected to be more effective. An application of this procedure to the European butterfly fauna with the Biodiversity Conservation Concern index calculated with two IUCN red listings (European and national) allowed the construction of a four-celled model that reflects different types of conservation priority. This combined use of international and regional red lists may be a tool to make practical decisions (e.g. allocation of funds or legislative actions) to preserve imperilled species. [source]


Challenging Wallacean and Linnean shortfalls: knowledge gradients and conservation planning in a biodiversity hotspot

DIVERSITY AND DISTRIBUTIONS, Issue 5 2006
Luis Mauricio Bini
ABSTRACT Knowledge about biodiversity remains inadequate because most species living on Earth were still not formally described (the Linnean shortfall) and because geographical distributions of most species are poorly understood and usually contain many gaps (the Wallacean shortfall). In this paper, we developed models to infer the size and placement of geographical ranges of hypothetical non-described species, based on the range size frequency distribution of anurans recently described in the Cerrado Biome, on the level of knowledge (number of inventories) and on surrogates for habitat suitability. The rationale for these models is as follow: (1) the range size frequency distribution of these species should be similar to the range-restricted species, which have been most recently described in the Cerrado Biome; (2) the probability of new discoveries will increase in areas with low biodiversity knowledge, mainly in suitable areas, and (3) assuming range continuity, new species should occupy adjacent cells only if the level of knowledge is low enough to allow the existence of undiscovered species. We ran a model based on the number of inventories only, and two models combining effects of number of inventories and two different estimates of habitat suitability, for a total of 100 replicates each. Finally, we performed a complementary analysis using simulated annealing to solve the set-covering problem for each simulation (i.e. finding the smallest number of cells so that all species are represented at least once), using extents of occurrence of 160 species (131 real anuran species plus 29 new simulated species). The revised reserve system that included information about unknown or poorly sampled taxa significantly shifted northwards, when compared to a system based on currently known species. This main result can be explained by the paucity of biodiversity data in this part of the biome, associated with its relatively high habitat suitability. As a precautionary measure, weighted by the inferred distribution data, the prioritization of a system of reserves in the north part of the biome appears to be defensible. [source]


Integrating DNA data and traditional taxonomy to streamline biodiversity assessment: an example from edaphic beetles in the Klamath ecoregion, California, USA

DIVERSITY AND DISTRIBUTIONS, Issue 5 2006
Ryan M. Caesar
ABSTRACT Conservation and land management decisions may be misguided by inaccurate or misinterpreted knowledge of biodiversity. Non-systematists often lack taxonomic expertise necessary for an accurate assessment of biodiversity. Additionally, there are far too few taxonomists to contribute significantly to the task of identifying species for specimens collected in biodiversity studies. While species level identification is desirable for making informed management decisions concerning biodiversity, little progress has been made to reduce this taxonomic deficiency. Involvement of non-systematists in the identification process could hasten species identification. Incorporation of DNA sequence data has been recognized as one way to enhance biodiversity assessment and species identification. DNA data are now technologically and economically feasible for most scientists to apply in biodiversity studies. However, its use is not widespread and means of its application has not been extensively addressed. This paper illustrates how such data can be used to hasten biodiversity assessment of species using a little-known group of edaphic beetles. Partial mitochondrial cytochrome oxidase I was sequenced for 171 individuals of feather-wing beetles (Coleoptera: Ptiliidae) from the Klamath ecoregion, which is part of a biodiversity hotspot, the California Floristic Province. A phylogram of these data was reconstructed via parsimony and the strict consensus of 28,000 equally parsimonious trees was well resolved except for peripheral nodes. Forty-two voucher specimens were selected for further identification from clades that were associated with many synonymous and non-synonymous nucleotide changes. A ptiliid taxonomic expert identified nine species that corresponded to monophyletic groups. These results allowed for a more accurate assessment of ptiliid species diversity in the Klamath ecoregion. In addition, we found that the number of amino acid changes or percentage nucleotide difference did not associate with species limits. This study demonstrates that the complementary use of taxonomic expertise and molecular data can improve both the speed and the accuracy of species-level biodiversity assessment. We believe this represents a means for non-systematists to collaborate directly with taxonomists in species identification and represents an improvement over methods that rely solely on parataxonomy or sequence data. [source]


Biodiversity hotspots, centres of endemicity, and the conservation of coral reefs

ECOLOGY LETTERS, Issue 6 2002
Terry P. Hughes
Abstract On land, biodiversity hotspots typically arise from concentrations of small-range endemics. For Indo-Pacific corals and reef fishes, however, centres of high species richness and centres of high endemicity are not concordant. Moreover ranges are not, on average, smaller inside the Central Indo-Pacific (CI-P) biodiversity hotspot. The disparity between richness and endemicity arises because corals and reef fishes have strongly skewed range distributions, with many species being very widespread. Consequently, the largest ranges overlap to generate peaks in species richness near the equator and the CI-P biodiversity hotspot, with only minor contributions from endemics. Furthermore, we find no relationship between the number of coral vs. fish endemics at locations throughout the Indo-Pacific, even though total richness of the two groups is strongly correlated. The spatial separation of centres of endemicity and biodiversity hotspots in these taxa calls for a two-pronged management strategy to address conservation needs. [source]


Patterns of bacterial diversity across a range of Antarctic terrestrial habitats

ENVIRONMENTAL MICROBIOLOGY, Issue 11 2007
Etienne Yergeau
Summary Although soil-borne bacteria represent the world's greatest source of biological diversity, it is not well understood whether extreme environmental conditions, such as those found in Antarctic habitats, result in reduced soil-borne microbial diversity. To address this issue, patterns of bacterial diversity were studied in soils sampled along a > 3200 km southern polar transect spanning a gradient of increased climate severity over 27° of latitude. Vegetated and fell-field plots were sampled at the Falkland (51°S), South Georgia (54°S), Signy (60°S) and Anchorage Islands (67°S), while bare frost-sorted soil polygons were examined at Fossil Bluff (71°S), Mars Oasis (72°S), Coal Nunatak (72°S) and the Ellsworth Mountains (78°S). Bacterial 16S rRNA gene sequences were recovered subsequent to direct DNA extraction from soil, polymerase chain reaction amplification and cloning. Although bacterial diversity was observed to decline with increased latitude, habitat-specific patterns appeared to also be important. Namely, a negative relationship was found between bacterial diversity and latitude for fell-field soils, but no such pattern was observed for vegetated sites. The Mars Oasis site, previously identified as a biodiversity hotspot within this region, proved exceptional within the study transect, with unusually high bacterial diversity. In independent analyses, geographical distance and vegetation cover were found to significantly influence bacterial community composition. These results provide insight into the factors shaping the composition of bacterial communities in Antarctic terrestrial habitats and support the notion that bacterial diversity declines with increased climatic severity. [source]


Pursuing community forestry in Liberia

ENVIRONMENTAL POLICY AND GOVERNANCE, Issue 5 2009
Jennifer N. Lamb
Abstract While Liberian forests are a biodiversity hotspot and integral to the livelihoods of indigenous communities, 14 years of conflict forestry turned this national asset into a source of economic inequality and corruption in an extreme example of a ,natural resource curse'. Moreover, overharvesting of timber through the conflict period has endangered community livelihoods and raised concerns regarding resource sustainability from international conservation organizations. Since the end of conflict in 2003, the Liberian government has forged international partnerships to create a reformed policy framework balancing commercial, conservation and community (the three Cs) interests. In an effort to contribute to the larger body of work on the role of natural resource management institutions in the creation and fostering of the resource curse, this paper offers a case study of timber in Liberia. We feel that an in-depth understanding of the Liberian case clarifies the challenge of timber as an extractive commodity and how the institutional framework can be shaped to provide a positive contribution to economic development. The discussion focuses on the historical development of Liberian land and forest tenure institutions that lead to poverty, ecological degradation and conflict. Tracing the more recent implementation of the three Cs, this paper analyzes the current conditions of community engagement and outlines critical steps to be taken for Liberia to escape further resource driven cycles of conflict. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment. [source]


Patterns in diversity of anurans along an elevational gradient in the Western Ghats, South India

JOURNAL OF BIOGEOGRAPHY, Issue 5 2007
Rohit Naniwadekar
Abstract Aim, To examine patterns in anuran species richness along an elevation gradient and identify factors that govern anuran species richness on a tropical elevational gradient. Location, Sampling for anurans was carried out in Kalakad Mundanthurai Tiger Reserve (KMTR) in the southern Western Ghats, India. Methods, Night-time sampling for anuran species richness was carried out from 20 November 2004 to 20 April 2005, during the north-east monsoon and dry seasons, using transects (50 × 2 m) and visual encounter surveys along the streams. The entire gradient was classified into thirteen 100-m elevation zones. Sampling at the alpha (single drainage basin) level was carried out in the Chinnapul River drainage basin (40,1260 m a.s.l.) and at the gamma (landscape) level in four drainage basins. Additionally, published records were used to arrive at an empirical species richness (S) for the entire landscape. Mid-Domain Null software was used to test for the possible influence of geometric constraints on anuran species at both the alpha and gamma levels. The influence of area under each elevation zone on empirical S was tested. The pattern in anuran species richness along the elevational gradient was investigated using: (1) species boundaries in each elevation zone and their habitat correlates, (2) abiotic factors as predictor variables, (3) mean snout vent lengths of anurans, and (4) correlation between the matrices of distance in the elevation zones based on microhabitat parameters and species composition. Cluster analysis on species presence,absence in the elevation zones was used to categorize the entire gradient into high, middle and low elevations. In these three elevation categories, pattern in composition of species was examined for endemism in Western Ghats,Sri Lanka biodiversity hotspot, uniqueness to an elevation zone, adaptations of adults and modes of breeding. Results, Species richness at the alpha level increased linearly with elevation, while at the gamma level there were three peaks. Maximum species richness was observed at the highest elevation (1200 m) at both the alpha and the gamma levels. The observed patterns differed significantly from mid-domain null predictions. The multi-modal pattern in species richness was a consequence of overlapping species range boundaries. Soil temperature was the best single measure in explaining the majority of variation in species richness at the alpha level (r2 = 0.846, P < 0.01). However, soil moisture was the best predictor when both the alpha and the gamma sites were pooled (r2 = 0.774, P < 0.01). Anuran body size decreased with an increase in elevation. The highest proportions of endemic and unique species were found at high elevations (> 700 m). The proportion of arboreal anurans increased from low to high elevation. Anurans exhibiting direct development were predominantly found at high elevations. Main conclusions, Geometric constraints did not influence anuran species richness along the elevational gradient. Overlapping range boundaries influenced species richness at the gamma level. Abiotic factors such as soil temperature and moisture influenced anuran species richness in the mountain range. The ,Massenerhebung effect' could be responsible for range restriction and endemism of anurans, differences in guilds and mode of reproduction. These findings highlight the importance of cloud forests for endemic anurans. [source]


Fine-scale comparative phylogeography of a sympatric sister species triplet of subterranean diving beetles from a single calcrete aquifer in Western Australia

MOLECULAR ECOLOGY, Issue 17 2009
M. T. GUZIK
Abstract Calcrete aquifers in the arid Yilgarn region of central Western Australia are a biodiversity hotspot for stygofauna. A distinct pattern of interspecific size class variation among subterranean dytiscid beetle species has been observed in 29 of these aquifers where either two or three small, medium and/or large sympatric species are found that are in some cases sister species. We used a 3.5 km2 grid of bores to sample dytiscids on a fine-scale and employed a comparative phylogeographical and population genetic approach to investigate the origins of a sympatric sister species triplet of diving beetles from a single aquifer. Mitochondrial DNA sequence data from the Cytochrome oxidase c subunit I gene revealed that all three species have high levels of haplotype diversity with ancient (,1 million years ago) intra-specific coalescence of haplotypes, but low levels of nucleotide diversity. Population analyses provide evidence for multiple expansion events within each species. There was spatial heterogeneity in the distribution of genetic variation and abundance both within and among the three taxa. Population analyses revealed significant fine-scale differentiation with isolation by distance for Paroster macrosturtensis and P. mesosturtensis, but not the smallest species P. microsturtensis. Haplotype network analyses provided limited or no evidence for past population fragmentation within the large and small species, but substantial historical divergence was observed in P. mesosturtensis that was not spatially structured. A patchy population structure with contemporaneous and historical isolation by distance in the three species is likely to have been a significant isolating and diversifying force, preventing us from ruling out a potential role for allopatric divergence during speciation of this beetle sister triplet. [source]


The 29°N latitudinal line: an important division in the Hengduan Mountains, a biodiversity hotspot in southwest China

NORDIC JOURNAL OF BOTANY, Issue 5 2009
Da-Cai Zhang
This paper aimed to explore the division of the southern and northern Hengduan Mountains based on gradients in species similarity and richness, and to analyze species richness in each sub-region. The Hengduan Mountain region was divided into nine latitudinal belts using one degree of latitude to define the belt after which distribution of seed plants within each latitudinal belt was recorded. Latitudinal patterns of species similarity were measured using the Jaccard similarity index for each pair of adjacent latitudinal belts. Non-metric multidimentional scaling (NMDS) was also used to analyze the similarity in species composition among the nine latitudinal belts. The latitudinal pattern of species similarity and the NMDS ordination both showed a great change in species composition across the 29°N latitudinal line, essentially dividing the Hengduan Mountain region into southern and northern sub-regions. Species richness, shown by the c-value of the species,area power function, and species,area ratio along a latitudinal gradient both showed a sharp decrease across the latitudinal belt from 29°0, to 29°59,N. The southern sub-region occupied 40% of the total area of the Hengduan Mountain region, but contained more than 80% of all the seed plants in the region. The higher species richness and endemism in the southern sub-region showed it to be the core of the Hengduan biodiversity hotspot, a result not unexpected because of the greater extremes of topography and wider diversity of habitats in the southern portion. [source]


The species,area relationship and confounding variables in a threatened monkey community

AMERICAN JOURNAL OF PRIMATOLOGY, Issue 4 2010
Andrew R. Marshall
Abstract This study investigates the species,area relationship (SAR) for forest monkeys in a biodiversity hotspot. The Udzungwa Mountains of Tanzania are well-suited to investigate the SAR, with seven monkey species in a range of fragment sizes (0.06,526,km2). We test the relationship between species richness and forest fragment size, relative to human and environmental factors. We distinguish resident and transitory species because the latter have an "effective patch size" beyond the area of forest. Forest area was the strongest (log-linear) predictor of species richness. However, forest area, elevation range and annual moisture index were intercorrelated. Previous knowledge of the relationship between elevation and tree communities suggests that the SAR is largely a result of habitat heterogeneity. Isolation by farmland (matrix habitat) also had a significant negative effect on species richness, probably exacerbated by hunting in small forests. The effect of area and isolation was less for transitory species. The human influence on species' presence/absence was negatively related to the extent of occurrence. Weaker relationships with temperature and precipitation suggest underlying climatic influences, and give some support for the influence of productivity. A reduced area relationship for smaller forests suggests that fragment sizes below 12,40,km2 may not be reliable for determining SAR in forest monkeys. Further practical implications are for management to encourage connectivity, and for future SAR research to consider residency, matrix classification and moisture besides precipitation. Am. J. Primatol. 72:325,336, 2010. © 2009 Wiley-Liss, Inc. [source]


Chagos feels the pinch: assessment of holothurian (sea cucumber) abundance, illegal harvesting and conservation prospects in British Indian Ocean Territory

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 1 2010
A. R. G. Price
Abstract 1.Data are analysed from visual censuses of shallow-water holothurians (sea cucumbers) in 72 shallow water transects 100,m×2,m within four atolls of Chagos. Mean holothurian abundance in Diego Garcia, where harvesting is absent, was 18.5 individuals/transect (all transects) and 55.4 individuals/transect (only those containing holothurians). In the three exploited atolls, mean abundance did not exceed 3.5 and 5.2 individuals/transect, respectively. 2.Comparison with data collected during this study and an earlier investigation reveals a marked decline over four years in both mean and maximum density of commercially valuable Stichopus chloronotus and Holothuria atra in Salomon and Peros Banhos, both exploited atolls, and also for Holothuria nobilis in the latter. 3.Holothurian counts were also made along an extensive transect (21,km×4,m) encircling Salomon atoll. Abundance showed highly significant negative correlation with fishing pressure, the latter estimated using an ordinal (0,3) scale (Rs=,0.605, P,0.01). Harvesting effects were not discernible using data from 200,m2 transects. 4.While recent studies have shown Chagos is virtually pristine regarding contaminant levels, its holothurian resources are under increasing pressure. Results from this study, and examination of Sri Lanka's fishing activity in distant waters, point to heavy and illegal harvesting. 5.Stronger measures are needed to control the illegal fishery, to prevent holothurian abundances falling to the non-sustainable levels now prevalent across much of the Indo-Pacific, and to ensure that Chagos remains a biodiversity hotspot and environment of international renown. Use of smaller surveillance vessels would facilitate this.Copyright © 2009 John Wiley & Sons, Ltd. [source]


Decadal changes (1996,2006) in coastal ecosystems of the Chagos archipelago determined from rapid assessment

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 6 2009
Andrew R.G. Price
Abstract 1.The atolls and islands comprising Chagos are a biodiversity hotspot of global conservation significance in a remote part of the central Indian Ocean. 2.This study examines the condition of the archipelago's coastal ecosystems by rapid environmental assessment at 21 sites/islands, which were also investigated a decade earlier using the same methodology. Major changes in ecosystem structure and environmental disturbance were determined. 3.Coral fish abundance was significantly lower in 2006 than 1996. Decrease in the physical structural complexity of the reefs, as a result of coral bleaching and mortality induced by the 1998 warming event, may have been a contributing factor. 4.Evidence of collecting/fishing was significantly greater in 2006 than 1996. This is attributed mainly to an illegal fishery for holothurians (sea cucumbers), which has expanded over recent years and now exerts substantial pressure on the resource. The significant decline observed in beach wood, a readily accessible fuel for fishing camps, is consistent with this. 5.Solid waste on islands was high (median 2 to 20 items m,1 beach) in both 1996 and 2006. Potentially harmful biological impacts, determined from other studies, include entanglement, toxic effects and provision of transport for invasives or other ,hitchhiker' species. 6.Significantly higher bird abundances were recorded in protected areas than ,unprotected' areas, attributed mainly to absence of predation by rats. 7.Rapid assessment augments more comprehensive ecosystem investigations. It provides a valuable snapshot of environmental conditions based upon a broad suite of features (ecosystems and disturbances) determined, concurrently, within the same site inspection quadrats and using the same scale of assessment. Copyright © 2009 John Wiley & Sons, Ltd. [source]


,Damsel in distress'- The tale of Miss Kerala, Puntius denisonii (Day), an endemic and endangered cyprinid of the Western Ghats biodiversity hotspot (South India)

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 1 2009
Rajeev Raghavan
Abstract 1.Denison's Barb, Puntius denisonii (Day) is an endemic and endangered cyprinid fish of the Western Ghats biodiversity hotspot in peninsular India, which is the focus of an organized yet undocumented fishery targeting juveniles for the international aquarium trade. 2.Research on P. denisonii has been very limited and there has been no systematic effort to assess and monitor their abundance, distribution and populations. 3.Anecdotal and circumstantial evidence indicates a highly restricted distribution, low abundance, declining populations, low catch per unit effort and increasing market prices, providing evidence of an impending conservation crisis and the need for urgent management of wild stocks. 4.This paper reviews current knowledge, provides results from the authors' field study and suggests priorities for conservation and management actions for P. denisonii in the streams of Kerala. Copyright © 2008 John Wiley & Sons, Ltd. [source]


Effects of Tea Plantations on Stream Invertebrates in a Global Biodiversity Hotspot in Africa

BIOTROPICA, Issue 4 2009
Olly van Biervliet
ABSTRACT Tropical stream ecosystems in montane forest watersheds are important centers of endemism and diversity and provide essential ecosystem services. These habitats are subject to a variety of stressors, including the conversion of adjacent terrestrial habitats from forest to agriculture, but the impacts of these anthropogenic effects are largely unknown because of the paucity of studies in these systems. In montane habitats in the wet tropics, large-scale cultivation of tea is common and can represent an important source of income at local and national scales. However, little is known about how tea cultivation impacts adjacent stream ecosystems. In this study, we examine stream macroinvertebrate assemblages in a biodiversity hotspot the East Usambara Mountains, Tanzania. Specifically, we compare diversity of macroinvertebrate assemblages found on cobbles in stream riffles in watersheds dominated by forest with those surrounded by tea cultivation. We found that streams surrounded by tea were characterized by significantly lower dissolved oxygen and had lower total estimated species richness and number of families. Furthermore, the richness of invertebrate taxa known to be sensitive to anthropogenic disturbance were substantially reduced in tea streams and general assemblage-level analysis shows significant differences in the composition of macroinvertebrate assemblages between tea and forested streams. Our results suggest that tea cultivation may reduce stream habitat quality and biodiversity in the East Usambaras. Further research is needed to evaluate the effects of tea cultivation on streams over longer times scales and to address methods for minimizing negative effects of agriculture on montane stream communities. [source]


Plant Community Structure in Tropical Rain Forest Fragments of the Western Ghats, India,

BIOTROPICA, Issue 2 2006
S. Muthuramkumar
ABSTRACT Changes in tree, liana, and understory plant diversity and community composition in five tropical rain forest fragments varying in area (18,2600 ha) and disturbance levels were studied on the Valparai plateau, Western Ghats. Systematic sampling using small quadrats (totaling 4 ha for trees and lianas, 0.16 ha for understory plants) enumerated 312 species in 103 families: 1968 trees (144 species), 2250 lianas (60 species), and 6123 understory plants (108 species). Tree species density, stem density, and basal area were higher in the three larger (> 100 ha) rain forest fragments but were negatively correlated with disturbance scores rather than area per se. Liana species density, stem density, and basal area were higher in moderately disturbed and lower in heavily disturbed fragments than in the three larger fragments. Understory species density was highest in the highly disturbed 18-ha fragment, due to weedy invasive species occurring with rain forest plants. Nonmetric multidimensional scaling and Mantel tests revealed significant and similar patterns of floristic variation suggesting similar effects of disturbance on community compositional change for the three life-forms. The five fragments encompassed substantial plant diversity in the regional landscape, harbored at least 70 endemic species (3.21% of the endemic flora of the Western Ghats,Sri Lanka biodiversity hotspot), and supported many endemic and threatened animals. The study indicates the significant conservation value of rain forest fragments in the Western Ghats, signals the need to protect them from further disturbances, and provides useful benchmarks for restoration and monitoring efforts. [source]


Diversity, endemism and evolution in the Coral Triangle

JOURNAL OF BIOGEOGRAPHY, Issue 10 2009
J. C. Briggs
Abstract In a recent paper by D. R. Bellwood and C. P. Meyer (,Searching for heat in a marine biodiversity hotspot', Journal of Biogeography, 2009, 36, 569,576), the authors had two evident objectives: (1) to disprove the theory that the geographical origins of reef organisms could be determined by locating concentrations of endemic species, and (2) to emphasize that the high diversity of the Coral Triangle was due to an accumulation of species from outside that area. With regard to the first point, no such theory had previously been proposed to my knowledge. Second, the accumulation theory was promoted without consideration of the facts supporting the centre of origin hypothesis, except to dismiss it by saying that it had its origin in pre-continental drift ideas. This short response outlines the properties and evidence for the operation of centres of origin in this region. [source]


Refining Biodiversity Conservation Priorities

CONSERVATION BIOLOGY, Issue 6 2005
GRANT M. HARRIS
Bosque del Atlántico; percepción remota; priorización; SIG; sitios prioritarios para la conservación Abstract:,Although there is widespread agreement about conservation priorities at large scales (i.e., biodiversity hotspots), their boundaries remain too coarse for setting practical conservation goals. Refining hotspot conservation means identifying specific locations (individual habitat patches) of realistic size and scale for managers to protect and politicians to support. Because hotspots have lost most of their original habitat, species endemic to them rely on what remains. The issue now becomes identifying where this habitat is and these species are. We accomplished this by using straightforward remote sensing and GIS techniques, identifying specific locations in Brazil's Atlantic Forest hotspot important for bird conservation. Our method requires a regional map of current forest cover, so we explored six popular products for mapping and quantifying forest: MODIS continuous fields and a MODIS land cover (preclassified products), AVHRR, SPOT VGT, MODIS (satellite images), and a GeoCover Landsat thematic mapper mosaic (jpg). We compared subsets of these forest covers against a forest map based on a Landsat enhanced thematic mapper. The SPOT VGT forest cover predicted forest area and location well, so we combined it with elevation data to refine coarse distribution maps for forest endemic birds. Stacking these species distribution maps enabled identification of the subregion richest in threatened birds,the lowland forests of Rio de Janeiro State. We highlighted eight priority fragments, focusing on one with finer resolved imagery for detailed study. This method allows prioritization of areas for conservation from a region >1 million km2 to forest fragments of tens of square kilometers. To set priorities for biodiversity conservation, coarse biological information is sufficient. Hence, our method is attractive for tropical and biologically rich locations, where species location information is sparse. Resumen:,Aunque hay acuerdo generalizado sobre las prioridades de conservación a escalas mayores (i. e., sitios prioritarios para la conservación de la biodiversidad), los límites son muy gruesos como para definir metas de conservación prácticas. La refinación de la conservación de sitios prioritarios significa la identificación de localidades específicas (parches de hábitat individuales) de tamaño y escala realistas para ser protegidos por gestores y apoyados por políticos. Debido a que los sitios prioritarios han perdido la mayor parte de su hábitat original, las especies endémicas dependen del que permanece. Ahora el asunto es identificar donde están el hábitat y las especies. Logramos lo anterior mediante técnicas directas de percepción remota y de SIG para identificar localidades específicas importantes para la conservación de aves en el sitio prioritario Bosque del Atlántico en Brasil. Nuestro método requiere de un mapa regional de la cobertura forestal actual, así que exploramos seis productos populares para el mapeo y cuantificación de bosques: campos continuos MODIS y una cobertura de suelo MODIS (productos preclasificados), AVHRR, SPOT VGT, MODIS (imágenes de satélite) y un mosaico GeoCover Landsat thematic mapper (jpg). Comparamos subconjuntos de estas coberturas forestales con las de un mapa basado en un Landsat enhanced thematic mapper. La cobertura forestal SPOT VGT predijo bien la superficie y localización del bosque, así que lo combinamos con datos de altitud para refinar los mapas generales de distribución de aves endémicas de bosques. La sobreposición de estos mapas de distribución permitió la identificación de la subregión más rica en aves amenazadas,los bosques en bajíos del Estado de Río de Janeiro. Dimos relevancia a ocho fragmentos prioritarios, con atención en uno con imágenes de resolución fina para estudio en detalle. Este método permite la priorización de áreas para conservación de fragmentos de decenas de kilómetros cuadrados en una región >1 millón km2. La información biológica general es suficiente para definir prioridades de conservación de la biodiversidad. Por lo tanto, nuestro método es atractivo para localidades tropicales y biológicamente ricas, para las que la información sobre la ocalización de las especies es escasa. [source]


Conservation of Brazilian Amphibians

CONSERVATION BIOLOGY, Issue 3 2005
DÉBORA L. SILVANO
The Brazilian Official List of Threatened Species and the results of a workshop for the Global Amphibian Assessment indicate that 26 species are threatened. The majority of these occur in the Atlantic Forest, one of the world's biodiversity hotspots. The main threat to amphibians is the destruction of their habitats through deforestation, conversion into agricultural land, mining, wildfires, and infrastructure development and urbanization. In Brazil little is known about other causes of amphibian decline observed worldwide, such as pesticides, infectious diseases, climate change, invasive species, or wildlife trade. Brazilian conservation policies include such important legal instruments as the Official List of Threatened Species and the selection of priority areas for conservation measures in all of Brazil's major biomes. Although there is little information on geographic distributions and the natural history and ecology of the large majority of the currently recognized species, a number of important regional studies for amphibian conservation are under way. New species are discovered each year. Resumen:,Brasil es el líder mundial en diversidad de anfibios, con 765 especies, la mayoría de las cuales han sido descritas en los últimos 40 años. La Lista Brasileña Oficial de Especies Amenazadas y los resultados de un taller para la Evaluación Global de Anfibios indican que 26 especies están amenazadas, la mayoría de ellas ocurre en el Bosque Atlántico, uno de los sitios de importancia para la biodiversidad global. La principal amenaza a los anfibios es la destrucción de sus hábitats por la deforestación, conversión a tierras agrícolas, minería, fuego no controlado, desarrollo de infraestructura y urbanización. En Brasil se conoce poco sobre otras causas de la declinación de anfibios observadas en todo el mundo, como pesticidas, enfermedades infecciosas, cambio climático, especies invasoras o comercio de vida silvestre. Las políticas Brasileñas de conservación incluyen importantes instrumentos legales como la Lista Oficial de Especies Amenazadas y la selección de áreas prioritarias para la conservación en todos lo biomas principales de Brasil. Existe escasa información sobre la distribución geográfica y la historia natural y ecología de la gran mayoría de las especies reconocidas actualmente, aunque se está desarrollando un importante número de estudios regionales para la conservación de anfibios. Cada año se descubren nuevas especies. [source]


Significance of Specimen Databases from Taxonomic Revisions for Estimating and Mapping the Global Species Diversity of Invertebrates and Repatriating Reliable Specimen Data

CONSERVATION BIOLOGY, Issue 2 2004
RUDOLF MEIER
More specifically, we demonstrate for a specimen database assembled during a revision of the robber-fly genus Euscelidia (Asilidae, Diptera) how nonparametric species richness estimators (Chao1, incidence-based coverage estimator, second-order jackknife) can be used to (1) estimate global species diversity, (2) direct future collecting to areas that are undersampled and/or likely to be rich in new species, and (3) assess whether the plant-based global biodiversity hotspots of Myers et al. (2000) contain a significant proportion of invertebrates. During the revision of Euscelidia, the number of known species more than doubled, but estimation of species richness revealed that the true diversity of the genus was likely twice as high. The same techniques applied to subsamples of the data indicated that much of the unknown diversity will be found in the Oriental region. Assessing the validity of biodiversity hotspots for invertebrates is a formidable challenge because it is difficult to decide whether species are hotspot endemics, and lists of observed species dramatically underestimate true diversity. Lastly, conservation biologists need a specimen database analogous to GenBank for collecting specimen records. Such a database has a three-fold advantage over information obtained from digitized museum collections: (1) it is shown for Euscelidia that a large proportion of unrevised museum specimens are misidentified; (2) only the specimen lists in revisionary studies cover a wide variety of private and public collections; and (3) obtaining specimen records from revisions is cost-effective. Resumen:,Sostuvimos que los millones de registros de especimenes publicados en miles de revisiones taxonómicas en décadas anteriores son una fuente de información costo-efectiva de importancia crítica para la incorporación de invertebrados en decisiones de investigación y conservación. Más específicamente, para una base de datos de especimenes de moscas del género Euscelidia (Asilidae, Diptera) demostramos como se pueden utilizar estimadores no paramétricos de riqueza de especies (Chao 1, estimador de cobertura basado en incidencia, navaja de segundo orden) para (1) estimar la diversidad global de especies, (2) dirigir colecciones futuras a áreas que están sub-muestreadas y/o probablemente tengan especies nuevas y (3) evaluar si los sitios globales de importancia para la biodiversidad basados en plantas de Myers et al. (2000) contienen una proporción significativa de invertebrados. Durante la revisión de Euscelidia el número de especies conocidas fue más del doble, pero la estimación de riqueza de especies reveló que la diversidad real del género probablemente también era el doble. Las mismas técnicas aplicadas a las sub-muestras de datos indicaron que gran parte de la diversidad no conocida se encontrará en la Región Oriental. La evaluación de la validez de sitios de importancia para la biodiversidad de invertebrados es un reto formidable porque es difícil decidir si las especies son endémicas de esos sitios y si las listas de especies observadas subestiman dramáticamente la diversidad real. Finalmente, los biólogos de la conservación requieren de una base de datos de especimenes análoga a GenBank, para obtener registros de especimenes. Dicha base de datos tiene una triple ventaja sobre la información obtenida de colecciones de museos digitalizadas. (1) Se muestra para Euscelidia que una gran proporción de especimenes de museo no revisados están mal identificados. (2) Sólo las listas de especimenes en estudios de revisión cubren una amplia variedad de colecciones privadas y públicas. (3) La obtención de registros en revisiones es costo-efectiva. [source]


Biodiversity hotspots, centres of endemicity, and the conservation of coral reefs

ECOLOGY LETTERS, Issue 6 2002
Terry P. Hughes
Abstract On land, biodiversity hotspots typically arise from concentrations of small-range endemics. For Indo-Pacific corals and reef fishes, however, centres of high species richness and centres of high endemicity are not concordant. Moreover ranges are not, on average, smaller inside the Central Indo-Pacific (CI-P) biodiversity hotspot. The disparity between richness and endemicity arises because corals and reef fishes have strongly skewed range distributions, with many species being very widespread. Consequently, the largest ranges overlap to generate peaks in species richness near the equator and the CI-P biodiversity hotspot, with only minor contributions from endemics. Furthermore, we find no relationship between the number of coral vs. fish endemics at locations throughout the Indo-Pacific, even though total richness of the two groups is strongly correlated. The spatial separation of centres of endemicity and biodiversity hotspots in these taxa calls for a two-pronged management strategy to address conservation needs. [source]


Threshold response of Madagascar's littoral forest to sea-level rise

GLOBAL ECOLOGY, Issue 1 2009
Malika Virah-Sawmy
ABSTRACT Aim, Coastal biodiversity hotspots are globally threatened by sea-level rise. As such it is important to understand how ecosystems resist, respond and adapt to sea-level rise. Using pollen, geochemistry, charcoal and diatom records in conjunction with previously published palaeoclimatic records, we investigated the mechanism, interactions and ecosystem response and resilience of Madagascar's littoral forest to late Holocene sea-level rise. Location, Sediment sequences were collected along the south-east coast of Madagascar in two adjacent habitats in Mandena; the highly diverse littoral forest fragment and species-poor Erica -matrix. Methods, We used a multi-proxy approach to investigate the relative influence of environmental changes on the littoral ecosystem. We reconstructed past vegetation and fire dynamics over the past 6500 years at two sites in the littoral forest using fossil pollen and macrofossil charcoal contained in sedimentary sequences. Alongside these records we reconstructed past marine transgressions from the same sedimentary sequences using geochemical analyses, and a salinity and drought index through the analysis of fossil diatoms. Results, Our findings indicated that it was the synergistic effect of sea-level rise coupled with rainfall deficits that triggered a threshold event with a switch from two types of littoral forest (an open Uapaca forest and a closed littoral forest fragment) to an Erica,Myrica heath/grassland occurring in approximately less than 100 years. Resilience to sea-level rise differed in the two adjacent habitats, suggesting that the littoral forest fragment was more resilient to the impacts of sea-level change and aridity than the open Uapaca woodland. Conclusions, We demonstrated that the littoral ecosystem was influenced by late Holocene sea-level rise and climatic desiccation. While climate change-integrated conservation strategies address the effects of climate change on species distribution and dispersal, our work suggests that more attention should be paid to the impacts of interactive climatic variables that affect ecosystem thresholds. [source]


Distribution pattern of endangered bird species in China

INTEGRATIVE ZOOLOGY (ELECTRONIC), Issue 4 2006
Fumin LEI
Abstract In this study, we determined six "hotspots" for avian biodiversity conservation in China. We analyzed the distribution patterns of 183 threatened bird species in China in conjunction with geographical data to produce a distribution map that shows the concentrations of threatened species. The six biodiversity hotspots are: the western Tianshan Mountains; the Qilian and Hengduan mountains; southern Anhui, southern Jiangsu, and the Zhejiang Hills; the Songliao Plain and the northern region of the North China Plain; the island of Taiwan; and the island of Hainan. Based on our analysis of a species,habitat matrix, species were determined to be distributed mainly in broadleaved forest, grassland and meadows, urban and agricultural areas, wetlands, and bush. Most species were commonly found to have a range of three to five different habitat types. Apart from the six biodiversity hotspots, six ecological clusters were determined. Protection strategies indicating different levels of habitat priority among the biodiversity hotspots were also recommended. [source]


Seamounts: identity crisis or split personality?

JOURNAL OF BIOGEOGRAPHY, Issue 12 2007
Craig R. McClain
Abstract At present, researchers propose that over 14,000 seamounts exist and, like their terrestrial analogues, function like islands. In addition, seamounts are described as oases, biodiversity hotspots, and lush coral/sponge gardens. Here I discuss the extent to which these tenets regarding seamounts may be inappropriate, suffer from a lack of support, and be over-generalizations of a broad range of environmental types encountered on seamounts. Ultimately, for seamount science to progress, we need to challenge our conventional wisdom on these habitats and the extent to which all seamounts function in a similar manner. [source]


Impact of cocoa farming on vegetation in an agricultural landscape in Ghana

AFRICAN JOURNAL OF ECOLOGY, Issue 2 2010
Alex Asase
Abstract Cocoa production occurs almost wholly within areas identified as biodiversity hotspots in West Africa and it has been noted as a major contributor to deforestation at the forest-agriculture interface. This study investigated the impact of cocoa farming on vegetation in relation to three land-use types of increasing cocoa production intensity from remnant native forest through shaded to unshaded cocoa farmlands in Ghana. The study used transects and forty-two 25 m × 25 m vegetation plots. The overall noncocoa plant species richness decreased significantly (95% CI) from the remnant native forest through shaded to the unshaded cocoa farmlands. Significant differences (P , 0.05) were also found in the mean density and basal area of noncocoa plants per hectare with the remnant native forest recording the highest values and the unshaded cocoa farmlands the lowest. The relative density of about 44.7% out of the 41 most abundant plant species declined in cocoa farmlands. The results of this study showed that cocoa farming could result in a drastic forest plant species loss with subsequent recruitment of nonforest species, forest plant species population decline as well as changes in the structural characteristics of the vegetation. This impact increases with increasing cocoa production intensity. Résumé En Afrique de l'Ouest, le cacao est produit presque entièrement dans des zones identifiées comme des hauts-lieux de la biodiversité et l'on a noté qu'il contribue toujours de façon importante à la déforestation à l'interface entre forêts et terres agricoles. Cette étude a analysé l'impact de la culture de cacao sur la végétation pour une utilisation des terres de trois types caractérisés par des intensités de production de cacao croissantes, allant des restes de forêt native à des exploitations ombragées et non ombragées de cacao, au Ghana. Cette étude a utilisé des transects et 42 parcelles de végétation de 25 m × 25 m. La richesse globale en espèces végétales - hors cacao - diminuait significativement (IC 95%) en passant des restes de forêt native aux exploitations de cacao ombragées et ensuite à celles qui sont exposées au soleil. On a aussi trouvé des différences significatives (P , 0,05) de la densité moyenne et de la surface basale par hectare des plants hors cacao, la forêt native restante donnant les valeurs les plus hautes et les exploitations exposées de cacao, les plus basses. La densité relative de près de 44,7% des 41 espèces végétales les plus abondantes diminuait dans les exploitations de cacao. Les résultats de cette étude ont montré que la production de cacao pouvait entraîner une perte drastique des espèces végétales forestières suivie d'un recrutement d'espèces non forestières, un déclin des populations d'espèces végétales forestières et des changements des caractéristiques structurelles de la végétation. Cette impacts augmentaient avec l'intensification de la production de cacao. [source]