Plant diversity and the stability of foodwebs

Abstract

Insect outbreaks in forest and agriculture monocultures led Charles Elton to propose, a half-century ago, that higher plant diversity stabilized animal foodweb dynamics in natural ecosystems. We tested this hypothesis by studying arthropod community dynamics in a long-term experimental manipulation of grassland plant species diversity. Over the course of a decade, we found that higher plant diversity increased the stability (i.e. lowered year-to-year variability) of a diverse (>700 species) arthropod community across trophic levels. As the number of plant species increased, the stability of both herbivore and predator species richness and of total herbivore abundance increased. The underlying mechanisms driving these diversity-stability relationships were plant diversity, via effects on primary productivity and plant community stability, and portfolio effects. Taken together, our results show that higher plant diversity provides more temporally consistent food and habitat resources to arthropod foodwebs. Consequently, actively managing for high plant diversity may have stronger than expected benefits for increasing animal diversity and controlling pest outbreaks.

Diversity of protists and bacteria determines predation performance and stability

“…Our finding supported that described by MacArthur (1955), where diversity at the prey level tended to stabilize the consumer population. Our results are also in line with previously published microcosm and field studies on the relationship of diversity, ecosystem functioning and stability in multitrophic systems (McGradySteed et al, 1997;Haddad et al, 2011) and suggest that diverse bacterial prey resources are a primary factor to make predator production more predictable.…”

“…Stability relies on interacting species and trophic interactions including the extent of predator feeding specialization and prey-predator connectivity (McCann, 2000;Haddad et al, 2011). We measured stability as the variability in predator production by using the CV, where high values exhibit low ecosystem reliability (Haddad et al, 2011;Leary et al, 2012).…”

Trophic complexity in aqueous systems: bacterial species richness and protistan predation regulate dissolved organic carbon and dissolved total nitrogen removal

“…This richness effect was observed irrespective of bacterial identities and top-down control by predators. Functional stability of environmental processes is a fundamental ecosystem parameter [45,46], with high C.V. reflecting low ecosystem reliability [12,47]. Our results are consistent with earlier findings showing that speciesrich ecosystems tend to use resources more efficiently [48] and that ecosystem processes stabilize with higher richness [49].…”

Plant diversity effects on insect herbivores and their natural enemies: current thinking, recent findings, and future directions

“…[1 ,2-8,9 ]). Studies have found that plant diversity positively influences arthropod diversity and abundance [3,4,8,10], and alters plant-arthropod and arthropod-arthropod interactions [3,7,11,12]. These findings emphasize that conserving and manipulating plant diversity in natural and managed systems, respectively, is crucial for maintaining ecosystem function [13][14][15].…”