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Human activities are drastically changing the composition of mammal communities and increasing species local extinctions. Although it is well recognized that species influence the way in which ecosystems function through the diversity of resource use traits, little is known regarding the consequences of ecosystem functioning on changing biodiversity. We summarized studies that analyzed the effects of anthropogenic disturbances on mammal assemblages in arid and semi-arid lands of the world. We analyze for the first time changes in functional diversity values under a wide variety of disturbances using a meta-analysis.

General mean effect size was significantly negative and marginally heterogeneous. Grouping into ecosystems showed a varied response, mostly negative but not significant. When considering disturbance types as moderator factor, functional diversity responds in a negative way to all types, but the strongest effects were seen when we analyzed the mechanism by which disturbance affects ecosystem. ’Herbivory’ effect was the least aggressive, and contrary, ’species change’ strongly and negatively affected functional diversity. When disturbance generates changes in species and resources, and new state properties highly differ from the initial state property, the regime shift seen in vegetation has drastic consequences over mammal functional diversity. This loss of functional diversity may generate positive feedbacks that help to maintain degraded states of the ecosystem. (C) 2012 Elsevier Ltd. All rights reserved.