As major disturbance agents, natural catastrophes impact habitats, thereby maintaining the dynamics of ecological communities. Such discrete events are expected to positively affect biodiversity because they generate high habitat heterogeneity and thus numerous ecological niche opportunities. Species typical of open and semi-open habitats, which are often of high conservation concern in modern anthropized landscapes, may benefit most from recurrent natural catastrophes that regularly reset ecosystems. We investigated bird community changes and species-specific responses to wildfire at two recently burnt temperate, montane-subalpine forest stands in an inner-Alpine Swiss valley, with a special focus on red-listed and conservation priority species. We compared bird community changes in burnt forests (spanning 13 years) with bird assemblages occurring in adjacent non-burned forest stands that served as quasi-experimental controls. Strong species-specific responses to wildfire were evidenced, resulting in a dramatic post-fire decrease in overall bird abundance and species richness. Yet, red-listed bird species and conservation priority species in Switzerland were substantially more common in burnt than in control forest stands. Many red-listed species showed a bell-shaped numeric response to wildfire over time, suggesting low habitat suitability just after fire, high habitat suitability at pioneer and early stages of vegetation succession, followed by a long-term decrease in suitability while vegetation becomes denser, especially at ground level. As established for Mediterranean regions where wildfires are especially frequent, this study shows that forest fires can also boost the populations of red-listed and priority bird species typical of open and semi-open habitats in temperate biomes. Prescribed forest fire might represent a management option for preserving threatened elements of biodiversity despite the intense public debate it will trigger.

Temporal changes of the breeding bird community in the burnt forest of Leuk Wildfires and windstorms are dynamic processes that can heavily impact habitats and alter their species compositions. Especially species of open and semi-open habitats can benefit from such disturbances, among them several bird species. In this study, we investigated the species-specific changes of the breeding bird community in the burnt forest of Leuk between 2006 and 2016, starting three years after the wildfire of 2003. Several species increased or decreased significantly in abundance after the fire event. A few species showed a complex reaction, where territory numbers increased after the fire, reaching a maximum after a few years and subsequently decreased. Interestingly, many of these bird species (e.g., Eurasian Wryneck, Common Redstart) are threatened and are priority species for conservation action. They may have benefitted from the first, open successional stages with a high proportion of bare ground, but are expected to decrease in abundance with the ongoing densification of the vegetation layers. Our study demonstrates that a large-scale forest fire can promote threatened bird species of open and semi-open habitats also in temperate regions. To what extent forestry measures, grazing or controlled fires can imitate the positive effects of wildfires is an open question and should be part of future research in the combined fields of forestry and conservation biology.

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