"...' An ecosystem ’s ability to recover and retain its structure and function following a transient and exogenous shock event.'
If a stress or disturbance does alter the ecosystem, then it should be able to bounce back quickly to resume its former ability to yield a service or utility rather than transform into a qualitatively different state that is controlled by a different set of processes. In order for ecosystem resilience to be defined, the ecosystem must have a degree of stability prior to the perturbation. Resilience relates to return to stability following perturbation (Holling 1973; Dawson et al. )..." (Harrington, R. et al., 2010

References:

• Dawson TP, Rounsevell MDA, Kluva´nkova´-Oravska´ et al (2010) Dynamic properties of complex adaptive ecosystems: implications for the sustainability of service provision. Biodivers Conserv (in Harrington, R. et al., 2010)

• Harrington, R. et al., 2010: Ecosystem services and biodiversity conservation: concepts and a glossary. Biodivers Conserv, DOI 10.1007/s10531-010-9834-9, Springer

• Holling CS (1973) Resilience and stability of ecological systems. Annu Rev Ecol Syst 4:1–23

• Bedeau, Caroline and Ng, Ee-Ling (2009): Ecosystem Resilience. (seminar paper, University of Kiel, Ecology Centre, Msc Environmental Science)