Diversity Of Common Species Research Articles

Effects of chronic anthropogenic disturbances on flesh fly (Diptera, Sarcophagidae) assemblages in areas of seasonally dry tropical forest

Seasonally dry tropical forests (SDTF) are among the most vulnerable ecosystems to chronic anthropogenic disturbances (CAD) such as agriculture, livestock and exploitation of wood and non-timber forest products which can negatively affect the local biota. We evaluated the influence of CAD and rainfall on the diversity of flesh flies (Diptera, Sarcophagidae) in the Brazilian Caatinga. We expected that the increase in CAD would negatively affect the specialist Sarcophagidae species and promote homogenisation of the assemblage. Specimens were collected using traps baited with fish, bovine spleen or human feces in six environments with different intensities of CAD—low, intermediate and high, based on land use and conservation status. We collected 29,810 specimens (3760 males, identified to 14 genera, 32 species). We observed a positive relationship between disturbance intensity and the abundance of synanthropic flies, mainly Tricharaea occidua. The diversity of common species and dominant species were affected only by CAD. There was also a marked substitution of species throughout the Caatinga environments (βSIM = 0.91), with few taxa (less than 50%) occurring indiscriminately in the areas under the three levels of impact. Chronic disturbances pose a constant threat to the conservation of flesh fly species. CAD act as a trigger for the homogenisation of Sarcophagidae assemblages, and magnify the dominance of synanthropic and generalist species. Empirical data on the effect of chronic disturbances can subsidize quantitative studies addressing local extinction. Our data strengthen the use of Sarcophagidae as biological indicators of anthropogenic action and can subsidize protocols for monitoring anthropogenic impacts in dry forests.

New Data on Spatio-temporal Stability and Variability of the Vietnamese Reefs

Research work on reefs of open South-China Sea and clause bay (South Vietnam), and the Gulf of Thailand investigated in the beginning of the 80s of the previous century were conducted in 2005-2007. A distinct dependence of the level of coral communities’ degradation on their closeness to settlements and aquaculture areas were established. Appreciable changes due to anthropogenic impact have occurred on the reefs that are the nearest to the city. There was a reduction in substrate cover by reef-building corals, a substitution of dominant scleractinian species, and a decrease in the numbers and diversity of common species of corallobionts. The index of species diversity for scleractinian also decreased. The seaweeds Chnoospora and Halimeda spread into all zones of the reefs. Changes in coral communities on more distant and protected reefs were not so marked

Grassland restoration to conserve landscape‐level biodiversity: a synthesis of early results from a large‐scale project

AbstractQuestionEuropean landscapes have long been influenced by intensifying use by humans. Although habitat restoration can reverse this process, it is often limited in scope by socioeconomic constraints. Here we present a grassland restoration project that is exceptional in spatial scale in Europe.LocationA total area of 760 ha of arable land was restored in the Egyek‐Pusztakócs unit (50 km2) of Hortobágy National Park, east Hungary, between 2005 and 2008.MethodsRestoration targeted alkali steppes and loess grasslands by sowing seeds of either two (alkali) or three (loess) foundation grass species. In 2009, we surveyed the vegetation in restored and target grasslands and quantified the factors influencing restoration success in a space‐for‐time substitution design.ResultsWe recorded 100 species of flowering plants, of which 37 species were non‐weed, ‘target’ species. Annual weeds dominated 1‐yr‐old fields but had decreased dramatically by the third year due to a developing perennial grass cover. Former alfalfa fields had proportionally fewer weeds than former cereal and sunflower fields. The diversity of common species and the cover of target species increased from 1‐ to 4‐yr‐old restored fields. Alkali‐restored fields had more heterogeneous vegetation and more species than loess‐restored fields. Distance to the target vegetation did not directly affect vegetation variables. There was significant spatial variability in vegetation development, possibly suggesting several local pathways of succession.ConclusionsGrassland restoration was generally successful in accelerating secondary succession towards alkali steppes and loess grasslands. However, further management is necessary to counter the homogenizing effects of litter accumulation, to reduce perennial weeds and to enhance the colonization of target species. Our project provides useful practical insights into grassland restoration and in applying restoration at a number of sites within a larger area to conserve biodiversity at the landscape scale.

Changes in the composition and structure of coral communities of Mju and Moon islands, Nha Trang Bay, South China Sea

In October 2003 and January 2005, comparative observations were made on the reefs of Mju and Moon islands near the city and port of Nha Trang, which we first investigated in 1981. Appreciable changes due to anthropogenic impact have occurred on the reefs that are the nearest to the city. There was a reduction in substrate cover by reef-building corals, a substitution of dominant scleractinian species, and a decrease in the numbers and diversity of common species of corallobionts. The index of species diversity for scleractinians also decreased. The seaweeds Chnoospora and Halimeda spread into all zones of the reefs. Changes in coral communities on more distant and protected reefs were not so marked.