Contrasting effects of habitat area and connectivity on evenness of pollinator communities

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

Losses of both habitat area and connectivity have been identified as important drivers of species richness declines, but little theoretical and empirical work exists that addresses the effect of fragmentation on relative commonness of highly mobile species 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 of indexes that give different weight to dominance and rarity. Second, we tested if traits related to mobility and diet breadth could explain the observed evenness patterns. We found a clear negative effect of area and a weaker, but positive effect of connectivity on evenness. Communities in small habitat fragments were mainly composed of mobile and generalist species. The higher evenness in small fragments could thereby be generated by highly mobile species that maintain local populations with frequent inter-fragment movements. Trait analysis suggested an increasing importance of dispersal over local recruitment, as we move from large to small fragments and from less to more connected fragments. Species richness and evenness were negatively correlated indicating that the two variables responded differently to habitat area and connectivity, although the mechanisms underlying the observed patterns are difficult to isolate. Even though habitat area and connectivity often decrease simultaneously due to habitat fragmentation, an interesting practical implication of the contrasting effect of the two variables is that the resulting community composition will depend on the relative strength of these two processes.

Detaljer

Författare
  • Lorenzo Marini
  • Erik Ockinger
  • Karl-Olof Bergman
  • Birgit Jauker
  • Jochen Krauss
  • Mikko Kuussaari
  • Juha Poyry
  • Henrik Smith
  • Ingolf Steffan-Dewenter
  • Riccardo Bommarco
Enheter & grupper
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Ekologi
  • Geovetenskap och miljövetenskap
Originalspråkengelska
Sidor (från-till)544-551
TidskriftEcography
Volym37
Utgivningsnummer6
StatusPublished - 2014
PublikationskategoriForskning
Peer review utfördJa