The relationship between biodiversity and ecosystem functioning is a central issue in ecology, but how this relationship is affected by nutrient stress is still unknown. In this study, we analyzed the phytoplankton diversity effects on community biomass and stability along nutrient gradients in an artificial eutrophic lake. Four nutrient gradients, varying from slightly eutrophic to highly eutr...

Knowledge of the composition of the bird community in Alto Balsas (southwestern Puebla, Central Mexico) is needed for management programs aiming at protection and conservation of bird species and their habitats I studied sites with tropical deciduous forest. Data were obtained during 1666 hours of field work in 238 days from March 1998 to September 2000. Six permanent transect (3.5 km long and ...

aim of this research was evaluated and compared of density (number tree per hectare), basal area and volume characteristics for estimation of tree species diversity in degraded forests. in order to, 73 hectares of kouhmian forests was inventory based on random systematic pattern with circular plots (10r and 26 plots). in each plot species, dbh and number of tree were measured and recorded. to e...

The conservationist community is giving special attention to epigean insects due to their importance in the preservation of terrestrial habitats. This work analysed the diversity, richness, abundance and similarity at the soil surface of Coleoptera composition among five environments: native forest, native grassland, Pinus elliottii plantation, Eucalyptus saligna plantation and degraded area by...

this study was performed  in second half of year 2009.for bird counting , monthly from septamber until march 2009. total counted birds in maroon lake were (971). maximum number of counted birds was in february  (191) and minimum of counted was in septamber (95). total counted birds in jaizan were (385. maximum number of the counted bird was in february (84) and minimum of counted (52) was in ja...

statistical studies on palynology contents of late cretaceous to paleocene age gurpi formation in a surface section in zagros basin,sw iran indicate changes in abundance, species diversity, ratio of spiniferites to cyclonephelium (s/c), palynological marine index(pmi) values and organic facies. these palynological variations clearly reflect fluctuations in relative sea-level and depositionalenv...