			Home About us Contact

Lowest Diversity (lowest + diversity)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

Genetic diversity of Chinese domestic goat based on the mitochondrial DNA sequence variation

JOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 1 2009
Y.-P. Liu
Summary The aim of this study was to characterize the genetic diversity of domestic goat in China. For this purpose, we determined the sequence of the mitochondrial DNA (mtDNA) control region in 72 individuals of the Yangtze River delta white goat, and reanalysed 723 published samples from 31 breeds/populations across China. All goat haplotypes were classified into four haplogroups (A,D) previously described. The phylogenetic pattern that emerged from the mtDNA control region sequence was confirmed by the analysis of the entire cytochrome b sequence of eight goats representative of the four haplogroups. It appeared that in Chinese domestic goat, haplogroups A and B were dominant and distributed in nearly all breeds/populations, while haplogroups C and D were only found in seven breeds/populations. Four breeds/populations contained all four haplogroups. When grouping the breeds/populations into five geographic groups based on their geographic distributions and ecological conditions, the southern pasturing area had the highest diversity whereas the northern farming area had the lowest diversity. 84.29% and 11.37% of the genetic variation were distributed within breeds and among breeds within the ecologically geographical areas, respectively; only 4% of genetic variation was observed among the five geographic areas. We speculate that the traditional seasonal pastoralism, the annual long-distance migrations that occurred in the past, and the commercial trade would account for the observed pattern by having favoured gene flows. [source]

Changes in carabid beetle diversity within a fragmented agricultural landscape

AFRICAN JOURNAL OF ECOLOGY, Issue 1 2003
C. N. Magagula
Abstract The distribution of carabid and cicindelid (Coleoptera: Carabidae) beetles in five distinct habitats (riparian, mature orchard, pine windbreak, young orchard, natural veld), within Tambuti Citrus Estate (Swaziland) was examined by pitfall trapping over 18 months. Habitats with high vegetation and litter cover had the highest species diversity and larger specimens, e.g. riparian border and pine windbreak, while the lowest diversity was observed in intensively managed mature citrus orchards. While species such as Tefflus delagorguei Guérin occurred in all the habitats sampled, certain species illustrated habitat specificity; e.g. Dromica ambitiosa Péringuey was observed only in the pine windbreaks while Haplotrachelus sp. Chaudoir occurred mainly in the vegetated riparian and natural veld habitats. Four unidentified carabid beetles were exclusive to the riparian border habitat. This habitat was the only one with a distinct assemblage of species in the agricultural mosaic studied. Multivariate analyses were used to assess the role of soil and environmental variables in relation to the ground beetle diversity within the agricultural mosaic studied. Résumé La distribution des carabes et des cicindèles (Coléoptères: Carabidae) dans cinq habitats distincts (riverain, verger mature, coupe-vent de pins, jeune verger, prairie naturelle) dans le Tambuti Citrus Estate (Swaziland) a été examinée pendant 18 mois au moyen de pièges. Les habitats qui avaient la végétation la plus haute et une litière présentaient la plus forte diversité en espèces et les plus grands spécimens, c'est-à-dire l'habitat riverain et les coupe-vent de pins, tandis qu'on observait la plus faible diversité dans les vergers de citronniers intensément gérés. Alors que des espèces comme Tefflus delagorguei Guérin se retrouvaient dans tous les habitats étudiés, certaines espèces illustraient une certaine spécificité, par exemple Dromica ambitiosa Péringuey, qui n'a été observée que dans les coupe-vent de pins tandis que Haplotrachelus sp. Chaudoir se trouvait surtout dans les habitats riverains et les prairies naturelles. Cinq coléoptères carabidés non identifiés se trouvaient exclusivement dans l'habitat riverain. Cet habitat était le seul à avoir un assemblage d'espèces distinct dans la mosaïque agricole étudiée. Des analyses multivariées ont été utilisées pour évaluer le rôle du sol et des variables environnementales par rapport à la diversité des coléoptères dans le sol de la mosaïque agricole étudiée. [source]

Diversity and extinction patterns of Permian coral faunas of China

LETHAIA, Issue 4 2000
Xiang-Dong Wang
Coral diversity and extinction patterns in the Permian of China are revealed through statistical analyses of 56 coral families, 263 genera and 2100 species from five consecutive time intervals. The highest coral diversity is in the Chuanshanian, with 753 species, 167 genera and 39 families. In contrast, the lowest diversity is in the Changhsingian, with only 68 species, 20 genera and 10 families. Two decreases in diversity can be recognized during the Permian. The first occurred at the end of the Maokouan (end-Guadalupian) and is marked by the loss of 75.6% of coral families, 77.8% of coral genera and 82.2% of coral species. The second major diversity drop took place at the end of the Changhsingian, when all rugose and tabulate corals became extinct. The extinction at the end of the Guadalupian in Pangea may be related to the middle Permian global regression. However, in South China the end-Maokouan extinction may be related to the eruption of the Omeishan Basalt. A triple-zoned palaeobiogeographical pattern is well expressed by coral diversity. [source]

Does Facilitation of Faunal Recruitment Benefit Ecosystem Restoration?

RESTORATION ECOLOGY, Issue 4 2002
An Experimental Study of Invertebrate Assemblages in Wetland Mesocosms
Abstract We used wetland mesocosms (1) to experimentally assess whether inoculating a restored wetland site with vegetation/sediment plugs from a natural wetland would alter the development of invertebrate communities relative to unaided controls and (2) to determine if stocking of a poor invertebrate colonizer could further modify community development beyond that due to simple inoculation. After filling mesocosms with soil from a drained and cultivated former wetland and restoring comparable hydrology, mesocosms were randomly assigned to one of three treatments: control (a reference for unaided community development), inoculated (received three vegetation/sediment cores from a natural wetland), and stocked + inoculated (received three cores and were stocked with a poorly dispersing invertebrate group,gastropods). All mesocosms were placed 100 m from a natural wetland and allowed to colonize for 82 days. Facilitation of invertebrate colonization led to communities in inoculated and stocked + inoculated treatments that contrasted strongly with those in the unaided control treatment. Control mesocosms had the highest taxa richness but the lowest diversity due to high densities and dominance of Tanytarsini (Diptera: Chironomidae). Community structure in inoculated and stocked + inoculated mesocosms was more similar to that of a nearby natural wetland, with abundance more evenly distributed among taxa, leading to diversity that was higher than in the control treatment. Inoculated and stocked + inoculated communities were dominated by non-aerial invertebrates, whereas control mesocosms were dominated by aerial invertebrates. These results suggest that facilitation of invertebrate recruitment does indeed alter invertebrate community development and that facilitation may lead to a more natural community structure in less time under conditions simulating wetland restoration. [source]