In both cases, the loss of species from a habitat which is being affected by eutrophication due to various sources may happen rather quickly and can as such be documented with standard biodiversity indicators, even if the response time may be protracted. If the environmental conditions are improved and thus re-establishing suitable growth conditions for plant species that are adapted to a nutrient-poor environment, it may take much longer for these plant species to reappear at the specific site. There may be several reasons for this, but one major reason is the fact that the dispersal of many plant species can be very slow.