Urban conservation gardening in the decade of restoration

Segar, J., et al. Nat Sustain 5, 649–656 (2022). https://doi.org/10.1038/s41893-022-00882-z

Global commitments and policy interventions for conservation have failed to halt widespread declines in plant biodiversity, highlighting an urgent need to engage novel approaches and actors. Here we propose that urban conservation gardening, namely the cultivation of declining native plant species in public and private green spaces, can be one such approach. We identify policy and complementary social mechanisms to promote conservation gardening and reform the existing horticultural market into an innovative nature-protection instrument. Conservation gardening can be an economically viable and participatory measure that complements traditional approaches to plant conservation.

Divergent roles of herbivory in eutrophying forests 

Segar, J., et al. Nat Commun 13, 7837 (2022). https://doi.org/10.1038/s41467-022-35282-6

Ungulate populations are increasing across Europe with important implications for forest plant communities. Concurrently, atmospheric nitrogen (N) deposition continues to eutrophicate forests, threatening many rare, often more nutrient-efficient, plant species. These pressures may critically interact to shape biodiversity as in grassland and tundra systems, yet any potential interactions in forests remain poorly understood. Here, we combined vegetation resurveys from 52 sites across 13 European countries to test how changes in ungulate herbivory and eutrophication drive long-term changes in forest understorey communities. Increases in herbivory were associated with elevated temporal species turnover, however, identities of winner and loser species depended on N levels. Under low levels of N-deposition, herbivory favored threatened and small-ranged species while reducing the proportion of non-native and nutrient-demanding species. Yet all these trends were reversed under high levels of N-deposition. Herbivores also reduced shrub cover, likely exacerbating N effects by increasing light levels in the understorey. Eutrophication levels may therefore determine whether herbivory acts as a catalyst for the “N time bomb” or as a conservation tool in temperate forests.

Prioritize grassland restoration to bend the curve of biodiversity loss

Staude, I., Segar, J., et al. Restoration Ecology 31, 5 (2023). https://doi.org/10.1111/rec.13931

In times of unprecedented climate change, ecological restoration efforts have a strong focus on forests for the purpose of carbon sequestration. Grasslands, in contrast, remain relatively neglected in global restoration policies. Concurrently, we are in the midst of a biodiversity crisis—it is estimated that 1 million species are globally threatened with extinction. Here, we present analyses from central Europe and southern Brazil that show that the majority of our endangered plant species are in fact found in open ecosystems. Using Germany as an example, we show that we could reduce plant extinction risk by up to 82% if we restore open, grassy ecosystems. This also holds true for southern Brazil, where grassland species constitute the single largest share of endangered species, but where grassy ecosystems continue to be systematically neglected by restoration policies. We further expand on our biodiversity argument to include the role that grassland restoration can play in mitigating climate change. We posit that ramping up grassland restoration efforts may not only be our best bet to bend the curve of biodiversity loss, but it will also make a critical contribution to the resilience of ecosystems in the dynamic decades to come. It is time for grassland restoration to receive higher priority in global restoration efforts and policy.