Contrasting effects of habitat area and connectivity on evenness of pollinator communities
2014 (English)In: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 37, no 6, 544-551 p.Article in journal (Refereed) Published
Losses of both habitat area and connectivity have been identified as important drivers of species richness declines, but littletheoretical and empirical work exists that addresses the effect of fragmentation on relative commonness of highly mobilespecies such as pollinating insects. With a large dataset of wild bee and butterfly abundances collected across Europe,we first tested the effect of habitat area and connectivity on evenness in pollinator communities using a large array ofindexes that give different weight to dominance and rarity. Second, we tested if traits related to mobility and diet breadthcould explain the observed evenness patterns. We found a clear negative effect of area and a weaker, but positive effectof connectivity on evenness. Communities in small habitat fragments were mainly composed of mobile and generalistspecies. The higher evenness in small fragments could thereby be generated by highly mobile species that maintain localpopulations with frequent inter-fragment movements. Trait analysis suggested an increasing importance of dispersalover local recruitment, as we move from large to small fragments and from less to more connected fragments. Speciesrichness and evenness were negatively correlated indicating that the two variables responded differently to habitat areaand connectivity, although the mechanisms underlying the observed patterns are difficult to isolate. Even though habitatarea and connectivity often decrease simultaneously due to habitat fragmentation, an interesting practical implicationof the contrasting effect of the two variables is that the resulting community composition will depend on the relativestrength of these two processes.
Place, publisher, year, edition, pages
Wiley-Blackwell, 2014. Vol. 37, no 6, 544-551 p.
IdentifiersURN: urn:nbn:se:liu:diva-104592DOI: 10.1111/j.1600-0587.2013.00369.xISI: 000337694100004OAI: oai:DiVA.org:liu-104592DiVA: diva2:697807