Hedging against biodiversity loss: Forest herbs’ performance in hedgerows across temperate Europe

Abstract

Questions: How do contrasting environmental conditions among forests and hedgerows affect the vegetative and reproductive performance of understorey forest herbs in both habitats? Can hedgerows support reproductive source populations of forest herbs, thus potentially allowing progressive dispersal of successive generations along these linear habitats? Location: Hedgerows and deciduous forest patches in agricultural landscapes across the European temperate biome. Methods: First, we assessed differences in environmental conditions among forests and hedgerows. Next, we quantified plant performance based on a set of functional life-history traits for four forest herbs (Anemone nemorosa, Ficaria verna, Geum urbanum, Poa nemoralis) with contrasting flowering phenology and colonisation capacity in paired combinations of forests and hedgerows, and compared these traits among both habitats. Finally, we assessed relationships between plant performance and environmental conditions in both habitats. Results: All study species showed a higher above-ground biomass in hedgerows than in forests. For Poa nemoralis and Geum urbanum, we also found a higher reproductive output in hedgerows, which was mainly correlated to the higher sub-canopy temperatures therein. The "ancient forest herb" Anemone nemorosa, however, appeared to have a lower reproductive output in hedgerows than in forests, while for Ficaria verna no reproductive differences were found between the two habitats. Conclusions: This is the first study on such a broad geographical scale to provide evidence of reproductive source populations of forest herbs in hedgerows. Our findings provide key information on strategies by which forest plants grow, reproduce and disperse in hedgerow environments, which is imperative to better understand the dispersal corridor function of these wooded linear structures. Finally, we highlight the urgent need to develop guidelines for preserving, managing and establishing hedgerows in intensive agricultural landscapes, given their potential to contribute to Journal of Vegetation Science VANNESTE ET Al.

Temperature effects on forest understorey plants in hedgerows: a combined warming and transplant experiment

“…in the wooded corridors. This reasoning is corroborated by an earlier study in which we compared the performance of common forest herbs from natural populations in hedgerows with those in forests, and found that A. nemorosa tended to grow taller and accumulate more biomass in hedgerows while G. urbanum produced more and heavier seeds (Vanneste et al, 2020d).…”

Nieuwe kansen voor biodiversiteit

“…Hagen en houtkanten die geconnecteerd zijn aan bosfragmenten, kunnen bijvoorbeeld als corridor dienen voor kwetsbare plantensoorten. 30 Daarnaast wordt er gezocht naar andere hoogwaardige toepassingen van hagen voor landbouwers, zoals de verwerking van houtsnoeisel in verwarmingstoepassingen (project Hagehelden en Kempens energiehout) of als bron van organische koolstof in de bodem. Houtige, opgaande vegetatie zoals bomen en houtkanten in de matrix van het landbouwlandschap hebben bovendien een bufferend effect op de lokale temperatuur en vochtigheid.…”

Biomass increment and carbon sequestration in hedgerow-grown trees

“…The increase in a tree's total leaf area is sufficient to overcome the decline in growth efficiency with increasing tree size, which causes the whole-tree carbon accumulation rate to increase (Stephenson et al 2014). In hedgerows and tree rows, tree heights and tree crowns are respectively lower and larger than in forests (Van Den Berge et al, 2021a;Vanneste et al, 2020b;Zhou et al, 2011), which probably results in even higher increases in leaf area with increasing tree size, and thus a more enhanced leaf area increase with age.…”