Extinction order and altered community structure rapidly disrupt ecosystem functioning

Abstract

By causing extinctions and altering community structure, anthropogenic disturbances can disrupt processes that maintain ecosystem integrity. However, the relationship between community structure and ecosystem functioning in natural systems is poorly understood. Here we show that habitat loss appeared to disrupt ecosystem functioning by affecting extinction order, species richness and abundance. We studied pollination by bees in a mosaic of agricultural and natural habitats in California and dung burial by dung beetles on recently created islands in Venezuela. We found that large-bodied bee and beetle species tended to be both most extinction-prone and most functionally efficient, contributing to rapid functional loss. Simulations confirmed that extinction order led to greater disruption of function than predicted by random species loss. Total abundance declined with richness and also appeared to contribute to loss of function. We demonstrate conceptually and empirically how the non-random response of communities to disturbance can have unexpectedly large functional consequences.

Trait‐based approaches to analyze links between the drivers of change and ecosystem services: Synthesizing existing evidence and future challenges

“…For example, the trait of body size in female bees acts as a response trait under agricultural intensification, but also acts as an effect trait that contributes to pollination efficiency. This correlation between effect and response traits may lead to a decline in the ecosystem service of pollination following agricultural intensification processes (Larsen, Williams, & Kremen, 2005). …”

Functional traits in agriculture: agrobiodiversity and ecosystem services

“…Is there a set of core traits that can be measured across trophic levels to provide an informative understanding of the ecosystem services in a given agroecosystems? Larsen et al [81] used an experimental approach to determine important traits to pollination and decomposition efficiency. A similar approach could be used in other systems to determine relevant traits.…”

Importance of pollinators in changing landscapes for world crops

“…In addition, to adequately judge the value of conserving and managing for wild pollinators, key pollinators in the main producing areas must be identified, their habitat requirements studied and the economic benefit of their presence estimated (e.g. Cane 1997b; Larsen et al 2005). Today, only few areas and crops have all the necessary data elements to access the impact of pollinator loss.…”

“…Fragmentation and degradation of near-and seminatural habitats can be detrimental to bee communities (Rathcke & Jules 1994;Kremen et al 2002Kremen et al , 2004Steffan-Dewenter et al 2002Larsen et al 2005;Cane et al 2006). The main causal factor is loss or dissociation of important resources for food and nesting (Hines & Hendrix 2005;Potts et al 2005).…”