Riparian galleries can act as refuge for birds in Eucalyptus plantations bit by wildfires

Abstract

Eucalyptus monocultures are known to hold reduced terrestrial biodiversity. We aimed to measure the effect of native riparian galleries embedded in plantations of the non-native Eucalyptus globulus in Portugal on bird richness and abundance. Between 2017 and 2019, we surveyed the breeding bird communities in native forests and two types of eucalyptus plantations: those bordering and those without native riparian galleries. The incidental occurrence of huge wildfires after the first year, allowed measuring the effects of native riparian galleries on the bird communities colonizing both types of plantations before and after the wildfires. Before the wildfires, bird communities in plantations with galleries were similar to those from native forests, presenting higher richness and abundance than those in plantations without galleries. After the wildfires, bird communities were similar in burnt and non-burnt plantations with galleries, which tended to have higher richness and abundance than both burnt and non-burnt plantations without galleries. Therefore, the presence of a riparian gallery was a better predictor than the fire occurrence to explain richness and abundance of bird communities in eucalyptus plantations. These striking results can be related to the relatively high availability of resources for birds in riparian galleries. We showed that native riparian galleries in eucalyptus plantations can act as a refuge for biodiversity, suggesting that they can contribute to maintain ecosystem functioning in landscapes threatened by wildfires.