Using assembly rules to measure the resilience of riparian plant communities to beaver invasion in subantarctic forests

Abstract

The present study measures the resilience of riparian herbaceous communities to beaver invasion in subantarctic forests of southern Chile and Argentina. Divergence in community composition and spatial structure was measured comparing beaver-disturbed and undisturbed vegetation assemblages along a sequence of beaver meadow ages; the former by performing a Principal Component Analysis and the later by estimating a co-occurrence index (C-score). Community composition and spatial structure of vegetation showed an increasingly divergent trend from undisturbed sites to older beaver meadows. These results indicated that understory vegetation in deciduous subantarctic forests was not resilient to beaver invasion. Using “assembly rules” as a conceptual framework, we propose a resilience index of host communities to disturbances caused by herbivore invaders that also can be used for subsequent restoration programs to monitor the effectiveness of intervention and mitigation efforts.