The Super-population Bridges the Habitat Diversity and Biodiversity

There is another way for new species to invade former settlers＇ habitats and successfully settle there; it is demonstrated that the su- per-population, which plays a key role in changing the world-wide environment, can create many new microhabitats in the old habitat, it is these new microhabitats that make new species easily come into the old habitat and settle there without fierce competition with former settlers. In other words, the super-population lead to the differentiation of the worldwide environment, lead to the environmental diversity in the biosphere. Through the differentiation of the environment the super-population produces many new microhabitats for new species, the appearance of many new microhabitats make it possible for new species to coexist with former settlers in the biosphere. The cqexistence of new species with former settlers or with new species＇ ＂ancestors＂ results in the increaseing in the biodiversity of the biosphere. The super-population is the founder of many new environments on the earth, it bridges the habitat diversity and the biodiversity. Now It is easy to explain the phenomenon that new species sometimes coexist with former settlers and even depend on former settlers in the biosphere rather than fierce competition between them.

Plant assemblage and diversity variation with human disturbances in coastal habitats of the western Arabian Gulf

Knowledge about plant diversity along disturbance gradients is essential for conservation and management of fragmented coastal habitats.This study examined the effects of human disturbance intensity in coastal habitats of Kuwait on diversity,composition,identity and assemblage of vascular plant species.Plant survey data from 113 plots （5m×5m each） were randomly selected in 51 sites at coastal fragmented habitats at three levels of disturbance intensities （high,moderate and low） and were statistically analyzed.The results revealed that about 76% of the recorded species are considered threatened species in Kuwait,most of which are being lost in high disturbed habitats.Disturbance led to the dominance of Zygophyllum qatarense,Cornulaca aucheri and Salsola imbricata,which are species of disturbance indicators.Richness,total plant cover and species diversity were higher in moderate and low disturbed habitats than in high disturbed habitats.Beta diversity between high and low disturbed habitats was higher than either between high and moderate,or between moderate and low disturbed habitats.Cluster analyses showed statistically significant differences in composition of plant assemblages,which indicate high beta diversity between the habitat types.Intensive urbanization and industrialization are among the most serious threats that contribute to declines in biological diversity and rapid fragmentation of coastal habitats in Kuwait.Establishing protective enclosures in the disturbed habitats,planting endangered and vulnerable species,and establishing a natural reserve at Nuwaiseeb are recommended conservation actions to avoid loss of the fragmented coastal habitats and to facilitate restoration of native plants.

The influence of urban park characteristics on bird diversity in Nanjing, China

Background:Habitat loss,fragmentation and decrease of habitat quality caused by urbanization have led to a dramatic decline in biodiversity worldwide.For highly urbanized areas,parks have become“islands”or habitat fragments for wildlife.As an important indicator group of urban ecosystem health,the response of birds to urbanization has attracted the global attention of ecologists.Understanding the key factors affecting bird diversity in urbanized environment is crucial to the protection of biodiversity in urban ecosystems.Methods:We used the line-transect method to survey birds in 37 urban parks in Nanjing,China.We also measured a number of park characteristics(area,isolation,shape index,environmental noise,distance to city center,and habitat diversity)that are commonly assumed to influence bird diversity.We then used the information-theoretic multi-model inference approach to determine which park characteristics had significant impacts on bird species richness.Results:We found that park area,habitat diversity and the distance to city center were the best positive predictors of bird species richness in Nanjing urban parks.By contrast,park isolation,park shape and environmental noise had little or no influence on bird diversity.Conclusions:Our study highlights the importance of park area,habitat diversity and the distance to city center in determining bird diversity in Nanjing city parks.Therefore,from a conservation viewpoint,we recommend that large parks with complex and diverse habitats far away from the city center should be retained or constructed to increase bird diversity in urban design and planning.

Demographic variation and habitat specialization of tree species in a diverse tropical forest of Cameroon

Background： Many tree species in tropical forests have distributions tracking local ridge-slope-valley topography. Previous work in a 50-ha plot in Korup National Park, Cameroon, demonstrated that 272 species, or 63% of those tested, were significantly associated with topography. Methods： We used two censuses of 329,000 trees ≥1 cm dbh to examine demographic variation at this site that would account for those observed habitat preferences. We tested two predictions. First, within a given topographic habitat, species specializing on that habitat （＇residents＇） should outperform species that are specialists of other habitats （＇foreigners＇）. Second, across different topographic habitats, species should perform best in the habitat on which they specialize （＇home＇） compared to other habitats （＇away＇）. Species＇ performance was estimated using growth and mortality rates. Results： In hierarchical models with species identity as a random effect, we found no evidence of a demographic advantage to resident species. Indeed, growth rates were most often higher for foreign species. Similarly, comparisons of species on their home vs. away habitats revealed no sign of a performance advantage on the home habitat. Conclusions＂ We reject the hypothesis that species distributions along a ridge-valley catena at Korup are caused by species differences in trees _〉1 cm dbh. Since there must be a demographic cause for habitat specialization, we offer three alternatives. First, the demographic advantage specialists have at home occurs at the reproductive or seedling stage, in sizes smaller than we census in the forest plot. Second, species may have higher performance on their preferred habitat when density is low, but when population builds up, there are negative density-dependent feedbacks that reduce performance. Third, demographic filtering may be produced by extreme environmental conditions that we did not observe during the census interval.

Predicting global numbers of teleomorphic ascomycetes

Sexual reproduction is the basic way to form high genetic diversity and it is beneficial in evolution and speciation of fungi.The global diversity of teleomorphic species in Ascomycota has not been estimated.This paper estimates the species number for sexual ascomycetes based on five different estimation approaches,viz.by numbers of described fungi,by fungus:substrate ratio,by ecological distribution,by meta-DNA barcoding or culture-independent studies and by previous estimates of species in Ascomycota.The assumptions were made with the currently most accepted,“2.2–3.8 million”species estimate and results of previous studies concluding that 90%of the described ascomycetes reproduce sexually.The Catalogue of Life,Species Fungorum and published research were used for data procurement.The average value of teleomorphic species in Ascomycota from all methods is 1.86 million,ranging from 1.37 to 2.56 million.However,only around 83,000 teleomorphic species have been described in Ascomycota and deposited in data repositories.The ratio between described teleomorphic ascomycetes to predicted teleomorphic ascomycetes is 1:22.Therefore,where are the undiscovered teleomorphic ascomycetes?The undescribed species are no doubt to be found in biodiversity hot spots,poorly-studied areas and species complexes.Other poorly studied niches include extremophiles,lichenicolous fungi,human pathogens,marine fungi,and fungicolous fungi.Undescribed species are present in unexamined collections in specimen repositories or incompletely described earlier spe-cies.Nomenclatural issues,such as the use of separate names for teleomorph and anamorphs,synonyms,conspecific names,illegitimate and invalid names also affect the number of described species.Interspecies introgression results in new species,while species numbers are reduced by extinctions.