Traditional Norwegian farming practices drive biodiversity – A case study from coastal heathlands

Human disturbances are often viewed as drivers of biotic homogenization, where generalist species thrive at the expense of specialists. However, human activities can also positively influence biodiversity. This study investigated how traditional farming practices, such as prescribed burning and grazing, have shaped biodiversity across multiple taxonomic groups – above and below ground – across three successional phases of a coastal heathland in Norway. We hypothesized that the vegetation-mosaics created by these traditional practices support greater biodiversity of plants and invertebrates than any single successional stage alone. We examined the impact of these practices on the taxonomic biodiversity of key organism groups (including plants, arthropods, nematodes, soil microbes, soil mesofauna and earthworms) across the three heathland successional phases. Our findings demonstrated: (i) how prescribed burning and grazing promote management induced vegetation mosaics; (ii) that this vegetation mosaic fosters high species diversity, with each phase supporting an unique set of taxa; (iii) that key organismal groups, including arthropods, fungi, and bacteria, largely contribute to the overall biodiversity; and (iv) that traditional management practices rejuvenate pasture, maintain high biodiversity, and play a crucial role in preventing uncontrolled large-scale fires. By analysing multiple organismal groups across heathland successional phases, we are the first ones in Norway to demonstrate how burning and grazing create a vegetation mosaic that enhances biotic heterogeneity instead of leading to diversity loss. These results highlight the importance of sustaining traditional farming practices for the preservation of biodiversity of plants and invertebrates in coastal heathlands.