Ecosystem recovery from disturbance depends on nutrient supply rate

Human disturbances alter the functioning and biodiversity of many
ecosystems. These ecosystems may return to their pre-disturbance state
after disturbance ceases, however humans have altered the environment in
ways that may change the rate or direction of this recovery. For example,
human activities have increased supplies of biologically-limiting
nutrients, such as nitrogen (N) and phosphorus (P), which can reduce
grassland diversity and increase productivity. We tracked the recovery of
a grassland for two decades following an intensive agricultural
disturbance under ambient and elevated nutrient conditions. Productivity
returned to predisturbance levels quickly under ambient nutrient
conditions, but nutrient addition slowed this recovery. In contrast, the
effects of disturbance on diversity remained hidden for 15 years, at which
point diversity began to increase in unfertilized plots. This work
demonstrates that enrichment of terrestrial ecosystems by humans may alter
the recovery of ecosystems and that disturbance effects may remain hidden
for many years.