Keystone patches: upholding diversity in multi-trophic metacommunities
(English)Manuscript (preprint) (Other academic)
Due to the destruction of their habitat some organisms have an uneven distribution across the landscape. In affected areas a community of interacting organisms may be fragmented into a network of smaller patches connected through dispersal of individuals of the different species. These metacommunities can be modelled with explicit dynamics and spatial structure, with dependence on both local processes (interactions between species within a patch) and global processes (dispersal of individuals between patches). Dispersal between patches is important for the operation of processes like recolonizations and ‘rescue effects’, processes which can counteract local extinctions and hence reduce the risk of global extinctions. Recent studies have applied network theory to real ecological communities, with a wide selection of indices available to characterise either an individual patch or the whole patch network. Certain keystone patches may be the most important in upholding the local or global diversity of a metacommunity and may then be identified by such a network index. A range of network indices were calculated for the patches in a large set of simulated metacommunities and all of the indices identified the keystone patch quality to a certain degree. Some of the indices were consistently better than the others and the dependence of the keystone quality on these indices was at least two times larger than for the others. The quality identified by the indices was of being more important for upholding local rather than global diversity. Many parameters were varied between the different metacommunities and as a result of this the models for identifying keystone patches yielded small R2 values and therefore were not proven to be dependable predictors if applied to particular metacommunities.
Extinction; food web; metacommunity; fragmented landscapes; keystone patches; network theory; landscape connectivity
IdentifiersURN: urn:nbn:se:liu:diva-76164OAI: oai:DiVA.org:liu-76164DiVA: diva2:512858