Resilience and Resistance

Resilience is the capacity of an ecosystem to regain characteristic processes over time following impacts or disturbance. 

Resistance is the ability of an ecosystem to maintain characteristic processes despite the impacts or disturbances.

Resource managers will benefit from considering and implementing efforts to maintain both resilience and resistance. Resilience is lost when thresholds are crossed and an ecosystem can not return to its original state via natural processes following an impact or disturbance.
Resistance is the strength in an ecosystem to utilize biotic and abiotic factors and ecological processes in an ecosystem that will reduce or limit the impact of a disturbance. 

An example of resistance is an ecosystem's ability to limit the population growth of invasive species. The ecosystem's resilience will define the ecosystem's ability to maintain processes during the impact of invasive species.

http://greatbasin.wr.usgs.gov/gbrmp/docs/SD/11%20Chambers%20Winnemucca%20Workshop.pdf