Diversity patterns, environmental drivers and changes in vegetation composition in dry inter-Andean valleys  

作　　者：Catalina Quintana Marco Girardello Anders S.Barfod Henrik Balslev 

机构地区：[1]Department of Bioscience,Ecoinformatics and Biodiversity Group,Aarhus University,Ny Munkegade 114,DK-8000 Aarhus C,Denmark [2]Departamento de Ciencias Biológicas,Pontificia Universidad Católica del Ecuador,Av.12 de Octubre 1076,Apartado postal 17012184,Quito,Ecuador

出　　处：《Journal of Plant Ecology》2017年第3期461-475,共15页植物生态学报（英文版）

摘　　要：Aims We studied diversity,patterns of endemism and turnover of veg-etation composition in dry inter-Andean valleys(DIAVs)where lit-tle is known about the influence of the abiotic drivers controlling plant species composition and occurrences,and the life forms that contribute most toα-andβ-diversity,respectively.This study was focused on DIAVs located in the highlands(800-2800 m)around the Equator(1°N-5°S).The following questions were addressed:(i)what differences exist between endemic and non-endemic species in terms of species number,frequency and abundance?(ii)are pat-terns ofα-andβ-diversity correlated with latitude?(iii)what are the major environmental drivers controlling spatial patterns in species composition and occurrence?Methods We established 63 transects of 5×100 m in areas with DIAV vegetation,impacted as little as possible by human activities.In each transect,all mature trees and shrubs were identified and counted to determine their density.The coverage of terrestrial herbs was estimated.Generalized additive models were used to quantify the relationship betweenα-andβ-diversity with latitude.To recordα-diversity,we used the exponential Shannon index.The Sørensen index was used to measureβ-diversity or species turnover.We used canonical correspondence analysis to deter-mine species composition and generalized linear mixed models to quantify simultaneously the determinants of species occur-rence across species and sites.The models were evaluated using the Akaike information criterion.All analyses were run separately for trees,herbs and shrubs.Important Findings Overall,we found that shrubs was the most diverse life form,constituting 43%(12%endemic)of the 313 species,followed by herbs(36%;11.5%endemic)and trees(20%;5%endemic).Trees comprise mostly species with low abundance(e.g.<3 individuals ha^(−1)),which was also true for herbs,whereas shrubs showed a larger number of abundant species(>30 individuals ha^(−1)),includ-ing four endemic species.Most of the endemic species were locally rare

关 键 词：ENDEMICS α-diversity β-diversity life forms Ecuador 

分 类 号：Q94[生物学—植物学]