Vegetation Pattern Modulates Ground Arthropod Diversity in Semi-Arid Mediterranean Steppes.

Fernando Meloni,Berta F Civieta,Susana Bautista,Juan A Zaragoza,María Lourdes Moraza

doi:10.3390/insects11010059

Abstract

The ecological functioning of dryland ecosystems is closely related to the spatial pattern of the vegetation, which is typically structured in patches. Ground arthropods mediate key soil functions and ecological processes, yet little is known about the influence of dryland vegetation pattern on their abundance and diversity. Here, we investigate how patch size and cover, and distance between patches relate to the abundance and diversity of meso-and microarthropods in semi-arid steppes. We found that species richness and abundance of ground arthropods exponentially increase with vegetation cover, patch size, and patch closeness. The communities under vegetation patches mainly respond to patch size, while the communities in the bare-soil interpatches are mostly controlled by the average distance between patches, independently of the concurrent changes in vegetation cover. Large patches seem to play a critical role as reserve and source of ground arthropod diversity. Our results suggest that decreasing vegetation cover and/or changes in vegetation pattern towards small and over-dispersed vegetation patches can fast lead to a significant loss of ground arthropods diversity in drylands.

Highlights

Drylands are arid, semiarid, and dry-subhumid ecosystems [1] that typically exhibit spatially patterned vegetation, with plants grouped in patches in a matrix of exposed soil
We found that vegetation cover ranged from 2.2 to 85.7%, average patch size ranged from 46.9 cm to 195.0 cm, the average distance between patches varied from 69.2 cm to 469.0 cm, and patch closeness ranged from 0.0021 cm−1 to 0.0144 cm−1 over the 14 sampling plots
Our results indicate that total vegetation cover is a critical factor modulating the ground meso- and microarthropods communities in drylands, which is in agreement with previous findings reported for different groups of ground arthropods [9,34,60,61]

Summary

Introduction

Semiarid, and dry-subhumid ecosystems [1] that typically exhibit spatially patterned vegetation, with plants grouped in patches in a matrix of exposed soil. Dryland degradation (e.g., due to disturbances such as grazing, fire, and drought) commonly reduces the vegetation cover and alters the spatial pattern of vegetation [10,11,12]. Several studies have pointed to the consequences of decreasing vegetation cover on the physical, chemical, and microbiological components and properties of dryland soils [16]. Soil fauna, such as ground arthropods, have received little attention in the context of dryland degradation [9,18]

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