Anthropogenic disturbances are key to maintaining the biodiversity of grasslands.

Z Y Yuan,F Jiao,Y H Li,Robert L Kallenbach

doi:10.1038/srep22132

Abstract

Although anthropogenic disturbances are often perceived as detrimental to plant biodiversity, the relationship between biodiversity and disturbance remains unclear. Opinions diverge on how natural diversity is generated and maintained. We conducted a large-scale investigation of a temperate grassland system in Inner Mongolia and assessed the richness-disturbance relationship using grazing intensity, the primary anthropogenic disturbance in the region. Vascular plant-species richness peaked at an intermediate level of anthropogenic disturbance. Our results support the Intermediate Disturbance Hypothesis, which provides a valid and useful measure of biodiversity at a metacommunity scale, indicating that anthropogenic disturbances are necessary to conserve the biodiversity of grassland systems.

Highlights

The Intermediate Disturbance Hypothesis (IDH) model suggests that any community can reach maximum diversity through multiple mechanisms[5,12], which can be described biologically or mathematically and might vary with locality and trophic level[4,17]
One general assumption of the IDH is that trade-offs between competitive ability and colonization ability facilitate the disturbance-mediated coexistence of competitively superior species, which are unable to thrive in highly disturbed sites, and colonizer species, which can be outcompeted by competitively superior species in less-disturbed sites[12,18]
Unimodal curves best described the relationships between the vascular plant-species richness and the human disturbance level (Fig. 1)

Summary

Introduction

The IDH model suggests that any community can reach maximum diversity through multiple mechanisms[5,12], which can be described biologically or mathematically and might vary with locality and trophic level[4,17]. Superior and colonizer species can, coexist between those extremes, leading to higher biodiversity at intermediate disturbance levels[3,12]. Factors such as species’ ability to utilize and partition resources, often reflected in productivity, are involved in the mechanisms that promote species coexistence[12,19]. Many reports that are critical of the IDH tested the diversity-disturbance relationships across multiple biomes[27] or, more commonly, at small spatial scales within communities[28,29,30]. The relationship between species richness and disturbance level was unimodal with a peak at an intermediate level of disturbance, supporting the IDH

Methods

Results

Conclusion