Land use effects and stream metabolic rates: a review of ecosystem response

Efeitos do uso do solo nas taxas metabólicas de córregos: uma revisão das respostas ecossistêmicas

Abstract

Aim

To conduct a review of the literature in order to identify the general stream metabolic responses to land use change.

Methods

I conducted a scientometric review analyzing the distribution of the studies among different environments, the land use scale used, and the general trends in stream metabolism response under each kind of land-use impact.

Major Results

Most of the analyzed studies were conducted in temperate environments, studying land-use impacts at catchment scale. Ecosystem metabolism responded to land use impacts most of the cases, especially under agricultural pressure. The general responses to land-use alterations were increases in rates of Gross Primary Production (GPP) and ecosystem Respiration (R). Primary production increases were mostly related to light and nutrient concentration increases, while R was usually related to water nutrient concentration, temperature and amount of particulate organic matter, but this general behavior can change under high impact levels where sometimes GPP decreases in response to turbidity increases. Riparian vegetation restoration have a positive effect in driving stream metabolic conditions in the direction of pristine condition, but the effectiveness of this approach is reduced in highly impacted systems.

Conclusions

To elucidate the mechanistic relations between stream metabolic changes and land use impacts is still one fundamental aspect to study in order to best predict effects of land use changes and establish management and protection programs. Thus, studies should focus on the causative relations between stream processes and land use changes considering different scales and multiple stress scenarios in order to improve our understanding about factors that drive the observed metabolic changes.

Keywords:
stream metabolism; tropical streams; riparian forests; land use; GPP