Effects of ecological restoration on Orthoptera assemblages in a Mediterranean steppe rangeland

Abstract

International audienceIn the last century, human activities have contributed to the fragmentation and the loss of 80 % of the original surface of a Mediterranean steppe rangeland in southeastern France. In a recent ecological restoration project, an intensively cultivated orchard of 357 ha planted in 1987 among the steppe vegetation was rehabilitated as a herbaceous habitat for steppe birds after its abandonment in 2006. In addition, three experimental restoration treatments (nurse species seeding, hay transfer; soil transfer) were applied at large scale to test the restoration of the original steppe vegetation. Our four-year study aimed to assess the effect of this rehabilitation and the restoration treatments on Orthoptera assemblages. Capturing the Orthoptera with sweep nets, we measured species richness, abundance, Shannon index, Shannon evenness, Renkonen similarity index and two community structure indices. Our results reveal no significant differences in Orthoptera species richness, abundance and diversity between control and reference steppe after 4 years, indicating that the rehabilitation and the three restoration treatments did not significantly accelerate natural recolonization. In the last year of survey, Orthoptera abundances were still significantly lower in the restored treatments than in the original steppe. Thus, future monitoring will need to determine whether abundance and structure similar to that of the reference steppe is achieved in these restored treatments

Differences in the insect fauna associated to a monocultural pasture and a silvopasture in Southeastern Brazil

“…Higher abundance of Diptera in pasture monocultures has been reported previously 42 , 43 . Composition of Orthoptera communities is known to be greatly affected by plant cover 44 and changes of environmental conditions, forming distinct communities characteristic of areas with low vegetational cover and others characteristic of high vegetation cover 45 – 47 . Some studies have reported that abundance of some groups falls with habitat simplification 48 , while in other groups abundance increases 49 which was also recorded in our study.…”

Asymmetric response of different functional insect groups to low‐grazing pressure in Eurasian steppe in Ningxia

“…Unmanaged steppe could enhance the abundance and diversity of Orthoptera assemblages (herbivores) compared with managed grasslands in Mediterranean steppe rangeland (Alignan, Debras, & Dutoit, ). However, Goodenough and Sharp () also found that moderate grazing intensity in both autumn and winter could enhance the abundance of butterflies while having disadvantageous effects on plants in winter (Goodenough & Sharp, ).…”

Key issues in Northwestern Mediterranean dry grassland restoration

“…In the Mediterranean Basin, arthropods, such as spiders (García et al 2009), beetles (Alignan et al 2018b) and Orthoptera (Alignan et al 2014(Alignan et al , 2018a Lortie et al (2004). Each process/filter is represented by a double horizontal line and the corresponding description is in italics on their left.…”

“…In the Mediterranean Basin, arthropods, such as spiders (García et al 2009), beetles (Alignan et al 2018b), and Orthoptera (Alignan et al 2014, 2018a) are used as bioindicators of restoration success because of their high sensitivity to changes in vegetation structure (height and density) or composition. Continuing to explore plant‐arthropod relationships and ecosystem engineers, such as ants and earthworms, will contribute to a more integrative response for overcoming key constraints in NwMedB grassland restoration.…”