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Tropical Biodiversity (tropical + biodiversity)

Distribution by Scientific Domains

Life Sciences	100%

Selected Abstracts

Wash and Spin Cycle Threats to Tropical Biodiversity

BIOTROPICA, Issue 1 2010
Lian Pin Koh
First page of article [source]

Can the tropical conservatism hypothesis explain temperate species richness patterns?

GLOBAL ECOLOGY, Issue 4 2009
An inverse latitudinal biodiversity gradient in the New World snake tribe Lampropeltini
ABSTRACT Aim, A latitudinal gradient in species richness, defined as a decrease in biodiversity away from the equator, is one of the oldest known patterns in ecology and evolutionary biology. However, there are also many known cases of increasing poleward diversity, forming inverse latitudinal biodiversity gradients. As only three processes (speciation, extinction and dispersal) can directly affect species richness in areas, similar factors may be responsible for both classical (high tropical diversity) and inverse (high temperate diversity) gradients. Thus, a modified explanation for differential species richness which accounts for both patterns would be preferable to one which only explains high tropical biodiversity. Location, The New World. Methods, We test several proposed ecological, temporal, evolutionary and spatial explanations for latitudinal diversity gradients in the New World snake tribe Lampropeltini, which exhibits its highest biodiversity in temperate regions. Results, We find that an extratropical peak in species richness is not explained by latitudinal variation in diversification rate, the mid-domain effect, or Rapoport's rule. Rather, earlier colonization and longer duration in the temperate zones allowing more time for speciation to increase biodiversity, phylogenetic niche conservatism limiting tropical dispersal and the expansion of the temperate zones in the Tertiary better explain inverse diversity gradients in this group. Main conclusions, Our conclusions are the inverse of the predictions made by the tropical conservatism hypothesis to explain higher biodiversity near the equator. Therefore, we suggest that the processes invoked are not intrinsic to the tropics but are dependent on historical biogeography to determine the distribution of species richness, which we refer to as the ,biogeographical conservatism hypothesis'. [source]

Integration of DNA barcoding into an ongoing inventory of complex tropical biodiversity

MOLECULAR ECOLOGY RESOURCES, Issue 2009
DANIEL H. JANZEN
Abstract Inventory of the caterpillars, their food plants and parasitoids began in 1978 for today's Area de Conservacion Guanacaste (ACG), in northwestern Costa Rica. This complex mosaic of 120 000 ha of conserved and regenerating dry, cloud and rain forest over 0,2000 m elevation contains at least 10 000 species of non-leaf-mining caterpillars used by more than 5000 species of parasitoids. Several hundred thousand specimens of ACG-reared adult Lepidoptera and parasitoids have been intensively and extensively studied morphologically by many taxonomists, including most of the co-authors. DNA barcoding , the use of a standardized short mitochondrial DNA sequence to identify specimens and flush out undisclosed species , was added to the taxonomic identification process in 2003. Barcoding has been found to be extremely accurate during the identification of about 100 000 specimens of about 3500 morphologically defined species of adult moths, butterflies, tachinid flies, and parasitoid wasps. Less than 1% of the species have such similar barcodes that a molecularly based taxonomic identification is impossible. No specimen with a full barcode was misidentified when its barcode was compared with the barcode library. Also as expected from early trials, barcoding a series from all morphologically defined species, and correlating the morphological, ecological and barcode traits, has revealed many hundreds of overlooked presumptive species. Many but not all of these cryptic species can now be distinguished by subtle morphological and/or ecological traits previously ascribed to ,variation' or thought to be insignificant for species-level recognition. Adding DNA barcoding to the inventory has substantially improved the quality and depth of the inventory, and greatly multiplied the number of situations requiring further taxonomic work for resolution. [source]

The Wildlife Picture Index: monitoring top trophic levels

ANIMAL CONSERVATION, Issue 4 2010
T. G. O'Brien
Abstract Although recent biodiversity loss has been compared with cataclysmic mass extinctions, we still possess few indicators that can assess the extent or location of biodiversity loss on a global scale. The Convention on Biological Diversity (CBD) has mandated development of indicators that can meet the needs of monitoring biodiversity by 2010. To date, many indicators rely on unwarranted assumptions, secondary data, expert opinion and retrospective time series. We present a new biodiversity indicator, the Wildlife Picture Index (WPI) that targets medium and large-sized terrestrial birds and mammals in forested and savannah ecosystems that. The WPI is a composite indicator based on the geometric mean of relative occupancy estimates derived from camera trap sampling at a landscape scale. It has been designed to meet the needs of a CBD indicator while avoiding many of the pitfalls that characterize some CBD indicators. We present an example using 8 years of camera trap data from Bukit Barisan Selatan National Park, Indonesia to show that the WPI is capable of detecting changes in the rate of loss of biodiversity, a key requirement of a CBD indicator. We conclude that the WPI should be effective at monitoring top trophic levels in forest and savannah ecosystems using primary data and can fill the gap in knowledge about trends in tropical biodiversity. [source]