The role of the seed bank in recovery of temperate heath and blanket bog following wildfires

Abstract

Questions Are the germinable seed banks of upland heath and blanket bog reduced following wildfires? Are some species at particular risk? Do the impacts of wildfires on seed banks differ between heathlands and blanket bog? Location Northern Ireland, United Kingdom. Methods Vegetation surveys and seed bank sampling were conducted in 2012 at burned and unburned areas within six upland sites where large wildfires had occurred during spring 2011. Differences in seedling abundance, species richness and Jaccard similarity indices between burned and unburned areas were compared using GLMMs. Differences in the community composition were examined using pRDA. Results In total, 24 of the 51 species in the vegetation were detected in the germinable seed bank. Species richness and the abundance of seedlings other than Calluna vulgaris were lower in areas where wildfires had occurred. Species composition of both germinable seed banks and vegetation differed between burned and unburned areas within sites; with negative associations between burned areas and some key indicator species including Drosera rotundifolia, Eriophorum vaginatum, Empetrum nigrum, Narthecium ossifragum and Trichophorum germanicum. We did not find any evidence of significant interactions between burning and habitat, suggesting that wildfires had similar impacts on each species regardless of the habitat in which they occurred. Conclusions This study differs from other UK studies in that it examines impacts of wildfires at sites that have not been previously intensively managed by burning. In particular, we highlight potential impacts on N. ossifragum and D. rotundifolia, which are key components of the upland flora and, to our knowledge, were not present in previous UK studies.

Initial ecological change in plant and arthropod community composition after wildfires in designated areas of upland peatlands

“…Present results were largely consistent with our initial hypotheses: recovery of plant and arthropod communities were incomplete in the short term; heathland and bogland specialist plants, particularly Sphagnum spp., were more affected by wildfires than generalist plants; and community composition of spiders and carabids, that is, abundance of particular species was more affected than overall species richness. This study was conducted as part of a wider study on the aftermath of wildfires in uplands designated for their ecological interest, which also found changes in soil chemistry (Kelly et al, 2018 ), reduced plant species diversity in the seed bank (Kelly et al, 2016 ), and greater impacts of wildfire on specialist upland and peatland birds compared with more generalist bird species (Reid et al, 2023 ) (Table 2 ). Recolonization by plants postfire is dependent on a number of factors including resprouting (from roots or stems) and seed banks and landscape scale factors such as dispersal (Kelly et al, 2016 ; Shepherd et al, 2021 ).…”

“…This study was conducted as part of a wider study on the aftermath of wildfires in uplands designated for their ecological interest, which also found changes in soil chemistry (Kelly et al, 2018 ), reduced plant species diversity in the seed bank (Kelly et al, 2016 ), and greater impacts of wildfire on specialist upland and peatland birds compared with more generalist bird species (Reid et al, 2023 ) (Table 2 ). Recolonization by plants postfire is dependent on a number of factors including resprouting (from roots or stems) and seed banks and landscape scale factors such as dispersal (Kelly et al, 2016 ; Shepherd et al, 2021 ). Postfire recolonization from nearby peatland and nonpeatland locations may be key in determining postfire species composition (Shepherd et al, 2021 ).…”

“…Further details of statistical methods are presented by Kelly et al ( 2016 ). All analyses were conducted using R 3.1.1 (R Core Team, 2020 ).…”

“…and seed banks and landscape scale factors such as dispersal (Kelly et al, 2016;Shepherd et al, 2021). Postfire recolonization from nearby peatland and nonpeatland locations may be key in determining postfire species composition (Shepherd et al, 2021).…”

“…Thus, low‐diversity landscapes perhaps comprising only one vegetational successional stage are created. Wildfires can also reduce seedbank species richness with specialist wetland species initially failing to recover (Kelly et al, 2016 ).…”