Trade‐offs between carbon stocks and biodiversity in European temperate forests

Abstract

Policies to mitigate climate change and biodiversity loss often assume that protecting carbon‐rich forests provides co‐benefits in terms of biodiversity, due to the spatial congruence of carbon stocks and biodiversity at biogeographic scales. However, it remains unclear whether this holds at the scales relevant for management, and particularly large knowledge gaps exist for temperate forests and for taxa other than trees. We built a comprehensive dataset of Central European temperate forest structure and multi‐taxonomic diversity (beetles, birds, bryophytes, fungi, lichens, and plants) across 352 plots. We used Boosted Regression Trees (BRTs) to assess the relationship between above‐ground live carbon stocks and (a) taxon‐specific richness, (b) a unified multidiversity index. We used Threshold Indicator Taxa ANalysis to explore individual species’ responses to changing above‐ground carbon stocks and to detect change‐points in species composition along the carbon‐stock gradient. Our results reveal an overall weak and highly variable relationship between richness and carbon stock at the stand scale, both for individual taxonomic groups and for multidiversity. Similarly, the proportion of win‐win and trade‐off species (i.e., species favored or disadvantaged by increasing carbon stock, respectively) varied substantially across taxa. Win‐win species gradually replaced trade‐off species with increasing carbon, without clear thresholds along the above‐ground carbon gradient, suggesting that community‐level surrogates (e.g., richness) might fail to detect critical changes in biodiversity. Collectively, our analyses highlight that leveraging co‐benefits between carbon and biodiversity in temperate forest may require stand‐scale management that prioritizes either biodiversity or carbon in order to maximize co‐benefits at broader scales. Importantly, this contrasts with tropical forests, where climate and biodiversity objectives can be integrated at the stand scale, thus highlighting the need for context‐specificity when managing for multiple objectives. Accounting for critical change‐points of target taxa can help to deal with this specificity, by defining a safe operating space to manipulate carbon while avoiding biodiversity losses.

Assessing the influence of harvesting intensities on structural diversity of forests in south-west Germany

“…Obviously, given the high average growing stock in the forests, harvesting improves light conditions near the ground and thus facilitates regeneration and establishment of more light demanding species (Boch et al 2013). This finding is in agreement with those of a recent study that showed that there is no positive effect of aboveground carbon stocks of European broadleaved forests on multi-taxa biodiversity (Sabatini et al 2019). This study showed that in particular among plant species, more species are lost than gained with increasing aboveground carbon stocks; including those shade-intolerant and drought-tolerant species which may be required for adaptation of forests to climate change (Kunz et al 2018).…”

“…Therefore, influences of harvests or harvesting intensity can have totally different impacts on single taxonomic groups or individual species within taxonomic groups. As has been shown by Sabatini et al (2019) within the taxonomic groups of vascular plants, lichens, fungi, bryophytes, beetles, and birds found in oak and beech dominated forests, the majority of species are not influenced by aboveground biomass C stocks, yet within each of these groups there are some winners and losers of increasing or decreasing stocks.…”

Protection gaps and restoration opportunities for primary forests in Europe

“…habitat of threatened species), as well as other ecosystem services (e.g. timber provisioning) would be a useful follow‐up undertaking for some biomes (Mönkkönen et al., 2014; Sabatini et al., 2019).…”

Carbon sequestration and biodiversity co‐benefits of preserving forests in the western United States

“…), but also weak relationships at the stand scale (Sabatini et al. ). We show that preserving forests in the western United States with high productivity and low vulnerability to future fire and drought can aid in the maintenance of vertebrate biodiversity, as these forests contain the highest proportion of critical habitat for threatened and endangered species.…”