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Research Highlight: Wu, D., Xu, C., Wang, S., Zhang, L., & Kortsch, S. (2022). Why are biodiversity–ecosystem functioning relationships so elusive? Trophic interactions may amplify ecosystem function variability. Journal of Animal Ecology, https://doi.org/10.1111/1365-2656.13808. There is consensus that average trends of ecosystem functions increase with species diversity. However, large variations in ecosystem function (VEF) in systems with similar diversity levels are commonly observed, yet not understood. In this study, Wu et al. (2022) integrate empirical aquatic food webs with a multitrophic model to show that VEF generally shows a hump-shaped pattern along the species richness gradient. This pattern is related to changes in taxa composition across trophic levels—the proportion of consumer species relative to basal species—along the gradient of species richness. Thus, VEF dependence on species diversity is driven by both bottom-up and top-down control that regulate taxa composition and taxa dominance. These results are corroborated with an independent food web dataset from the Gulf of Riga. An important implication of this study is that biodiversity loss may not only reduce the mean levels of ecosystem functioning, but also increase unpredictability of functions by generating greater function variability. © 2022 The Author. Journal of Animal Ecology © 2022 British Ecological Society.

In the domain of lattice and porous material geometric modeling, the problem of data size is central.

Ensuring stable food supplies is a major challenge for the 21st century. There is consensus that increased food production is necessary, but not sufficient, to achieve food security, and that agriculture should also aim at stabilizing crop production over time. In this context, biodiversity-based approaches to food security are increasingly being supported based on the fact that biodiversity can increase and stabilize crop production. However, agricultural systems are often highly fragmented and our current understanding of how such fragmentation affects biodiversity and food production remains incomplete, thus limiting our capacity to manage agricultural landscapes for food security. We developed a spatially explicit model of crop dynamics to investigate how the fragmentation of natural habitats for agricultural conversion impacts food production and food security, with a focus on animal-dependent crop production. Fragmentation produces a variety of spatial and biodiversity-mediated effects that affect both the mean and stability (temporal invariability) of animal-dependent crop production. Fragmentation has a dual effect on animal-dependent production. On the one hand, spatial aggregation of natural land decreases animal-dependent production by reducing the Landscape Pollination Potential, a metric that captures fragmentation and pollinator spillover effects within the agricultural landscape. But aggregation increases animal-dependent production by maintaining a higher pollinator diversity in larger fragments of natural habitat. The net effects of fragmentation on animal-dependent crop production depend on the land-use change pattern, the strength of the pollinator spillover to crop land and the animal pollination dependence of crops. Synthesis. Our study sheds new light in the food security debate by showing that high and stable crop production depends on biodiversity and the spatial fragmentation of agricultural landscapes, and by revealing the ecological mechan, Ensuring stable food supplies is a major challenge for the 21st century. There is consensus that increased food production is necessary, but not sufficient, to achieve food security, and that agriculture should also aim at stabilizing crop production over time. In this context, biodiversity-based approaches to food security are increasingly being supported based on the fact that biodiversity can increase and stabilize crop production. However, agricultural systems are often highly fragmented and our current understanding of how such fragmentation affects biodiversity and food production remains incomplete, thus limiting our capacity to manage agricultural landscapes for food security. We developed a spatially explicit model of crop dynamics to investigate how the fragmentation of natural habitats for agricultural conversion impacts food production and food security, with a focus on animal-dependent crop production. Fragmentation produces a variety of spatial and biodiversity-mediated effects that affect both the mean and stability (temporal invariability) of animal-dependent crop production. Fragmentation has a dual effect on animal-dependent production. On the one hand, spatial aggregation of natural land decreases animal-dependent production by reducing the Landscape Pollination Potential, a metric that captures fragmentation and pollinator spillover effects within the agricultural landscape. But aggregation increases animal-dependent production by maintaining a higher pollinator diversity in larger fragments of natural habitat. The net effects of fragmentation on animal-dependent crop production depend on the land-use change pattern, the strength of the pollinator spillover to crop land and the animal pollination dependence of crops. Synthesis. Our study sheds new light in the food security debate by showing that high and stable crop production depends on biodiversity and the spatial fragmentation of agricultural landscapes, and by revealing the ecological mechan

Global change degrades ecosystems worldwide. Scientific research has advanced our knowledge of the impacts of global change on ecosystems. Comparatively, however, it remains unclear how ecosystems recover after disturbances. In this perspective, I contend that ecological restoration should advance toward a general, dynamic theory that describes the recovery rates and trajectories of ecosystems along restoration. This approach should address three fundamental challenges corresponding to three components of ecological systems: complexity (how do we quantify ecological restoration?), space (what are the spatial scales of restoration?), and global change (how does global change determine restoration's reference states?). A generic model and experiment based on metacommunities is used to illustrate how these challenges can be addressed. Given the extent of ecosystem degradation and the international consensus to restore ecosystems, revealing the patterns and mechanisms underlying recovery is a fundamental and timely issue toward a general theory of ecological restoration

Multiple large-scale restoration strategies are emerging globally to counteract ecosystem degradation and biodiversity loss. However, restoration often remains insufficient to offset that loss. To address this challenge, we propose to focus restoration science on the long-term (centuries to millennia) re-assembly of degraded ecosystem complexity integrating interaction network and evolutionary potential approaches. This approach provides insights into eco-evolutionary feedbacks determining the structure, functioning and stability of recovering ecosystems. Eco-evolutionary feedbacks may help to understand changes in the adaptive potential after disturbance of metacommunity hub species with core structural and functional roles for their use in restoration. Those changes can be studied combining a restoration genomics approach based on whole-genome sequencing with replicated space-for-time substitutions linking changes in genetic variation to functions or traits relevant to the establishment of evolutionarily resilient communities. This approach may set the knowledge basis for future tools to accelerate the restoration of ecosystems able to adapt to ongoing global changes. © 2020, Springer Nature Limited.

Given that few ecosystems on the Earth have been unaffected by humans, restoring them holds great promise for stemming the biodiversity crisis and ensuring ecosystem services are provided to humanity. Nonetheless, few studies have documented the recovery of ecosystems globally or the rates at which ecosystems recover. Even fewer have addressed the added benefit of actively restoring ecosystems versus allowing them to recover without human intervention following the cessation of a disturbance. Our metaanalysis of 400 studies worldwide that document recovery from large-scale disturbances, such as oil spills, agriculture and logging, suggests that though ecosystems are progressing towards recovery following disturbances, they rarely recover completely. This result reinforces conservation of intact ecosystems as a key strategy for protecting biodiversity. Recovery rates slowed down with time since the disturbance ended, suggesting that the final stages of recovery are the most challenging to achieve. Active restoration did not result in faster or more complete recovery than simply ending the disturbances ecosystems face. Our results on the added benefit of restoration must be interpreted cautiously, because few studies directly compared different restoration actions in the same location after the same disturbance. The lack of consistent value added of active restoration following disturbance suggests that passive recovery should be considered as a first option; if recovery is slow, then active restoration actions should be better tailored to overcome specific obstacles to recovery and achieve restoration goals.We call for a more strategic investment of limited restoration resources into innovative collaborative efforts between scientists, local communities and practitioners to develop restoration techniques that are ecologically, economically and socially viable. © 2018 The Author(s).