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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2020

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Abstract

Degraded tropical forests that were converted into pastures dominated by exotic grasses are a challenge for restoration due to arrested succession. Nucleation is a suitable strategy to restore such abandoned pastures as it can overcome seed and site limitation, and would foster the recovery of structural, functional, and species diversity. To explore the outcomes of different nucleation techniques in terms of richness, functional diversity, resource offer, and species and trait composition during the first year after implementation in an abandoned pasture in the tropical Andes, we conducted a field experiment with four nucleation treatments established in 1-m2 subplots, i.e. natural regeneration (control), seed rain transfer, seed bank transfer, and pre-grown plant mats. Number of species, functional diversity, proportion of natives, flowering and fruiting were response variables of the nucleation treatments and time since restoration using linear mixed-effects models. Species and trait composition trajectories over time were depicted with NMDS. Species richness and functional diversity of understory vegetation increased over time and with nucleation, being significantly higher by the final survey. Seed bank transfer introduced most species to the area in comparison to natural regeneration. Functional diversity, proportion of native, flowering, and fruiting species changed with time albeit with no differences among treatments. Species and trait composition showed convergence over time, which stresses the strong influence of environmental filtering in early restoration of abandoned pastures. Although positive aspects of planting trees and shrubs cannot be neglected, we argue that the incorporation of (several) more sophisticated nucleation techniques is beneficial for restoration of tropical forests.

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Abstract

Late-spring frosts (LSFs) affect the performance of plants and animals across the world’s temperate and boreal zones, but despite their ecological and economic impact on agriculture and forestry, the geographic distribution and evolutionary impact of these frost events are poorly understood. Here, we analyze LSFs between 1959 and 2017 and the resistance strategies of Northern Hemisphere woody species to infer trees’ adaptations for minimizing frost damage to their leaves and to forecast forest vulnerability under the ongoing changes in frost frequencies. Trait values on leaf-out and leaf-freezing resistance come from up to 1,500 temperate and boreal woody species cultivated in common gardens. We find that areas in which LSFs are common, such as eastern North America, harbor tree species with cautious (late-leafing) leaf-out strategies. Areas in which LSFs used to be unlikely, such as broad-leaved forests and shrublands in Europe and Asia, instead harbor opportunistic tree species (quickly reacting to warming air temperatures). LSFs in the latter regions are currently increasing, and given species’ innate resistance strategies, we estimate that ∼35% of the European and ∼26% of the Asian temperate forest area, but only ∼10% of the North American, will experience increasing late-frost damage in the future. Our findings reveal region-specific changes in the spring-frost risk that can inform decision-making in land management, forestry, agriculture, and insurance policy.