Biological soil crusts across disturbance-recovery scenarios: effect of grazing regime on community dynamics

Ecological Applications
By: , and 

Links

Abstract

Grazing represents one of the most common disturbances in drylands worldwide, affecting both ecosystem structure and functioning. Despite the efforts to understand the nature and magnitude of grazing effects on ecosystem components and processes, contrasting results continue to arise. This is particularly remarkable for the biological soil crust (BSC) communities (i.e., cyanobacteria, lichens, and bryophytes), which play an important role in soil dynamics. Here we evaluated simultaneously the effect of grazing impact on BSC communities (resistance) and recovery after livestock exclusion (resilience) in a semiarid grassland of Central Mexico. In particular, we examined BSC species distribution, species richness, taxonomical group cover (i.e., cyanobacteria, lichen, bryophyte), and composition along a disturbance gradient with different grazing regimes (low, medium, high impact) and along a recovery gradient with differently aged livestock exclosures (short-, medium-, long-term exclusion). Differences in grazing impact and time of recovery from grazing both resulted in slight changes in species richness; however, there were pronounced shifts in species composition and group cover. We found we could distinguish four highly diverse and dynamic BSC species groups: (1) species with high resistance and resilience to grazing, (2) species with high resistance but low resilience, (3) species with low resistance but high resilience, and (4) species with low resistance and resilience. While disturbance resulted in a novel diversity configuration, which may profoundly affect ecosystem functioning, we observed that 10 years of disturbance removal did not lead to the ecosystem structure found after 27 years of recovery. These findings are an important contribution to our understanding of BCS dynamics from a species and community perspective placed in a land use change context.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Biological soil crusts across disturbance-recovery scenarios: effect of grazing regime on community dynamics
Series title Ecological Applications
DOI 10.1890/13-1416.1
Volume 24
Issue 7
Year Published 2014
Language English
Publisher Ecological Society of America
Contributing office(s) Southwest Biological Science Center
Description 15 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Ecological Applications
First page 1863
Last page 1877
Country Mexico