Abstract
- Understanding how differences in intensity and frequency of
hydrological disturbances affect the resistance and resilience of
aquatic organisms is key to manage aquatic systems in a fast-changing
world. Organisms’ responses to environmental changes can be influenced
by different life strategies. Some aquatic organisms have strategies
that improve the permanence in aquatic systems, while others use
strategies that enhance colonization.
- Therefore, we carried out a manipulative experiment to understand the
resistance/resilience of aquatic insects based on their functional
characteristics to hydrological disturbances in streams in the Cerrado
hotspot.
- We placed 200 artificial substrates in five streams and submitted them
to changing water flow regimes that differed both in frequency and
intensity. Then we observed the response of the aquatic community for
39 days. We used a Hierarchical Bayesian strategy approach to estimate
the probabilities of permanence and colonization of each life strategy
group (nine groups).
- We observe that the most intense changes in the water flow tend to
affect the permanence of almost all groups. However, this effect was
reduced in intensity over time. On the other hand, less frequent
disturbances, regardless of intensity, tend to reduce the permanence
of most groups of aquatic insects over time. The difference in the
effect of disturbance regarding intensity (higher or lower) may be
related to a greater dispersal capacity of some groups.
- These results are worrisome in a scenario of reduced riparian
vegetation around streams and with the expectation of precipitation to
become more concentrated in shorter periods of time due to climate
change in the Cerrado hotspot. Together, these anthropogenic changes
tend to increase the effect of runoff on the lotic systems and,
consequently, reduces the permanence of many groups of aquatic insects
in their habitat, particularly those with traits associated with
permanence.