Plant diversity increases predation by ground‐dwelling invertebrate predators

Lionel R. Hertzog,Wolfgang W. Weisser,Sebastian T. Meyer,Anne Ebeling

doi:10.1002/ecs2.1990

Lionel R. Hertzog, Wolfgang W. Weisser + Show 2 more

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https://doi.org/10.1002/ecs2.1990

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Abstract

AbstractGlobal declines in biodiversity have raised concerns over the implications of diversity loss for the functioning of ecosystems. Plant diversity loss has impacts throughout food webs affecting both consumer communities and ecosystem functions mediated by consumers. Effects of plant diversity loss on communities of invertebrate predators have been documented, yet little is known about how these translate into variations in predation rates. We measured predation rates along two plant diversity gradients in grassland experiments manipulating species richness and functional diversity. Measurements were conducted at two different heights (ground and vegetation) and in two different seasons (spring and summer), using three different types of baits. Our results show that overall predation rates increase with plant species richness, but effects are seasonally variable and are much more pronounced on the ground than in the vegetation. Plant functional diversity did not consistently affect predation rates in our experiments. Potential mechanistic explanations for an effect of plant diversity on predation include higher complementarity between predator species or reduced intraguild predation with increasing structural complexity at higher plant diversity. These results underline the importance of high local plant diversity for natural pest control.

Highlights

Positive effects of local plant diversity on ecosystem functions such as plant productivity, nutrient cycling, or decomposition are a consensus among the scientific community (Hooper et al 2005)
Regarding the identity of predator groups that we could identify based on the attack marks left in the dummies, biting insects and gastropods were the main group of predators with 52% and 46% of the dummies with attack marks showing marks from these two groups in the Main Experiment and 53% and 35% in the Trait-Based Experiment (TBE), respectively
Our experiment has demonstrated an increase in invertebrate predation with higher plant species richness, an effect that was most pronounced on the ground

Summary

Introduction

Positive effects of local plant diversity on ecosystem functions such as plant productivity, nutrient cycling, or decomposition are a consensus among the scientific community (Hooper et al 2005). Changes in plant diversity can affect the structure, composition, and stability of whole food webs (Scherber et al 2010, Haddad et al 2011), affecting related ecosystem functions. Linking shifts in consumer communities and the ecosystem function they mediate to changes in plant diversity is more complex than for directly plant-associated functions (Duffy 2002, Ives et al 2005). These relationships have been less intensively studied (Cardinale et al 2012). No study has so far measured predation rates caused by diverse predator communities

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