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Landscape fragmentation and defaunation have major impacts on plant dispersal and dynamics. However, whether the impact of such perturbations on seed dispersal and recruitment change in sign and strength across habitats and spatial scales, and whether they amplify or buffer each other, remains largely unknown. To evaluate, for the first time, the joint impact of fragmentation and defaunation on seed dispersal effectiveness (SDE) across spatial scales (e.g., short- and long-distance seed dispersal), we utilized the long-term field data of a mammal-dispersed tree (Pyrus bourgaeana) in a spatially explicit individual-based model. By means of simulation experiments, we evaluated the effects of different levels of landscape fragmentation and defaunation on SDE and tree recruitment. Our simulation results revealed that the direction and magnitude of the fragmentation effect on SDE depended on its strength (mild, severe) and the spatial scale considered. Severe fragmentation decreased SDE for short- and intermediate-distance seed dispersal. Interestingly, mild and severe fragmentation increased SDE of long-distance seed dispersal, suggesting a positive effect of such perturbations (i.e., an increase in the proportion of successful long-distance dispersal events). Though defaunation had a consistently negative effect on overall SDE, its magnitude was highly species- and spatial–scale-dependent. The impact of defaunation on seed dispersal distance was also species-specific: the proportion of long-distance dispersal increased under total badger (Meles meles) defaunation but decreased under total fox (Vulpes vulpes) defaunation. A pervasive integration of seed dispersal distance into the SDE framework is essential to most comprehensively understand the scale-dependent nature of human activity impacts on plant dynamics. In the long term, strong perturbations (landscape fragmentation and defaunation) could select either for or against long-distance seed dispersal, altering in di

Landscape fragmentation and defaunation have major impacts on plant dispersal and dynamics. However, whether the impact of such perturbations on seed dispersal and recruitment change in sign and strength across habitats and spatial scales, and whether they amplify or buffer each other, remains largely unknown. To evaluate, for the first time, the joint impact of fragmentation and defaunation on seed dispersal effectiveness (SDE) across spatial scales (e.g., short- and long-distance seed dispersal), we utilized the long-term field data of a mammal-dispersed tree (Pyrus bourgaeana) in a spatially explicit individual-based model. By means of simulation experiments, we evaluated the effects of different levels of landscape fragmentation and defaunation on SDE and tree recruitment. Our simulation results revealed that the direction and magnitude of the fragmentation effect on SDE depended on its strength (mild, severe) and the spatial scale considered. Severe fragmentation decreased SDE for short- and intermediate-distance seed dispersal. Interestingly, mild and severe fragmentation increased SDE of long-distance seed dispersal, suggesting a positive effect of such perturbations (i.e., an increase in the proportion of successful long-distance dispersal events). Though defaunation had a consistently negative effect on overall SDE, its magnitude was highly species- and spatial–scale-dependent. The impact of defaunation on seed dispersal distance was also species-specific: the proportion of long-distance dispersal increased under total badger (Meles meles) defaunation but decreased under total fox (Vulpes vulpes) defaunation. A pervasive integration of seed dispersal distance into the SDE framework is essential to most comprehensively understand the scale-dependent nature of human activity impacts on plant dynamics. In the long term, strong perturbations (landscape fragmentation and defaunation) could select either for or against long-distance seed dispersal, altering in di

The European Commission has recently adopted its EU Biodiversity Strategy for 2030, which sets out an ambitious plan for reversing biodiversity loss, and preserving and restoring protected ecosystems. A central binding target is focused on enlarging the EU network of legally protected areas (Natura 2000, the largest global network of the world), and on maintaining or improving the conservation status of all vulnerable habitats and species included in them. Biological invasions are currently a major threat to Natura 2000, so fulfilling the objectives of the EU Biodiversity Strategy calls for stepping up the implementation and enforcement of the relevant legislation on the matter, which has been thoroughly revised over the last decade. We discuss here the regulatory aspects of legislation on invasive alien species (IAS) that need to be optimised to address the challenge posed by biological invasions to the Natura 2000 network in the light of the new EU Biodiversity Strategy. We highlight that, while the EU has designed a solid regulatory framework to tackle the threat of biological invasions, its successful implementation will mainly rely upon appropriate national enforcement and allocation of economic and human resources. Despite previous warnings, the creation of dedicated EU funding mechanisms to support a comprehensive implementation of the legislation still remains a priority. Due to the yet small number of IAS regulated at the EU level, prevention and management of IAS will largely depend on national and local administration efforts, and on regional coordination and cooperation across neighbouring countries. Therefore, a wellintegrated system responsible for biosecurity, pests and invasive alien organisms at the EU level would be better accomplished through a centralized, independent EU agency of new creation. Likewise, the establishment of a similar lead agency at the MS level, with special focus on IAS management in Natura 2000, is recommended to navigate the

[Aim]: Invasive alien species (IAS) can cause profound impacts on ecosystem function and diversity, human health, well- being and livelihoods. Climate change is an important driver of biological invasions, so it is critical to develop models and climate- driven scenarios of IAS range shifts to establish preventive measures. In this study, we analyse how projected changes in the frequency and magnitude of climate extreme events could affect the spread of the six most widely distributed invasive vertebrate species in the Iberian Peninsula., [Location]: Iberian Peninsula., [Taxa]: Red avadavat (Amandava amandava), common waxbill (Estrilda astrild), monk parakeet (Myiopsitta monachus), rose- ringed parakeet (Psittacula krameri), American mink (Neovison vison) and pond slider (Trachemys scripta)., [Methods]: We followed best- practice standards for species distribution models (SDMs) regarding handling of the response and predictor variables, model building and evaluation using metrics that assess different facets of model performance. We used an ensemble approach with four modelling methods of varying complexity, including both regression- based and tree- based machine- learning algorithms. We analysed five regional models for current (1971– 2000) and future climate (2021– 2050). We used principal components analysis to assess consensus among model outputs and positively weighed predictions from well- performing models., [Results]: Selected models showed high consensus and good predictive capacity on block cross- validation areas. Generalized Linear Models and Generalized Additive Models scored highest in reliability (calibration), but Bayesian Additive Regression Trees provided the best balance between calibration and discrimination capacity. Forecasts include visible changes in environmental favourability, with losses generally outweighing the gains, but with some areas becoming more favourable for several species., [Main conclusions]: Increased frequency and/or intensity of climate extreme events associated with ongoing climate change are projected to reduce overall invasion risk for the species examined although increases in favourability should be expected locally.

The acceptance and usefulness of simulation models are often limited by the efficiency, transparency, reproducibility, and reliability of the modelling process. We address these issues by suggesting that modellers (1) “trace” the iterative modelling process by keeping a modelling notebook corresponding to the laboratory notebooks used by empirical researchers, (2) use a standardized notebook structure and terminology based on the existing TRACE documentation framework, and (3) use their notebooks to compile TRACE documents that supplement publications and reports. These practices have benefits for model developers, users, and stakeholders: improved and efficient model design, analysis, testing, and application; increased model acceptance and reuse; and replicability and reproducibility of the model and the simulation experiments. Using TRACE terminology and structure in modelling notebooks facilitates production of TRACE documents. We explain the rationale of TRACE, provide example TRACE documents, and suggest strategies for keeping “TRACE Modelling Notebooks.”, Ministerio de Economía y Competitividad (MINECO), Université de Lyon ((UdL)/Agence Nationale de la Recherche (ANR), Agence Nationale de la Recherche (ANR)-JCJC PEPPER, Scottish Government Rural Affairs Food and Environment Strategic Research Programme, Depto. de Biodiversidad, Ecología y Evolución, Fac. de Ciencias Biológicas, TRUE, pub

Contemporary defaunation has profound ecological consequences ranging from local or even global co-extinctions of interacting species to the loss of ecosystem functions and services critical for humanity. Other components of global change (climate change, introduced pests, land use changes) are also harming ecosystem functioning by augmenting tree mortality worldwide. Defaunation and increased tree mortality often coincide in many human-altered ecosystems but whether they interact, leading to non-additive effects on ecosystem functioning, remains largely unknown. However, under some ecological circumstances, the decline or extirpation of one species due to defaunation can be neutralized by increases in the abundance of some functionally similar species (i.e. ‘density compensation’). We combined long-term field data with individual-based modelling to investigate the potential interactive effects of seed disperser loss, increased tree mortality and density compensation on seed dispersal in a heterogeneous landscape. Our simulation experiments showed that both stressors markedly limit not only the quantity of seed dispersal but also its quality since the impact on seed dispersal strongly varied among habitat types that differ strikingly in suitability for tree establishment. Density compensation had a marked positive effect on seed dispersal which, however, was largely limited under increased tree mortality. The combined negative effects of defaunation and increased tree mortality on seed dispersal were lower than the expected additive effect. This highlights the need to account for the joint operation of multiple stressors to accurately predict the impacts of global change on the link between biodiversity and ecosystem functioning., Ministerio de Ciencia, Innovación y Universidades (MICINN), Ministerio de Economía y Competitividad (MINECO), Depto. de Biodiversidad, Ecología y Evolución, Fac. de Ciencias Biológicas, TRUE, pub

Large-scale abortion of immature fruits is a pervasive phenomenon across seed plants due to maternal physiological decisions associated with matching resources with fruit crop size. Aborted fruits are usually disqualified from studies of both fruit production and seed dispersal. However, a considerable number of developing seeds occur within immature aborted fruits. We evaluated the untested hypotheses that seeds within aborted fruits are viable and that incomplete predation of seeds within aborted fruits by hoarding rodents provides, in addition to seed movement, increased germination and seedling emergence. To this end, we studied the system composed by the Iberian pear Pyrus bourgaeana and several rodent species in Mediterranean Spain. About a third of aborted fruits found beneath tree canopies (n = 2430) were partially eaten by rodents. Using a seed sowing experiment, we revealed that a considerable fraction of seeds from P. bourgaeana aborted fruits are viable, germinating, and emerging seedlings. Paradoxically, however, these seeds are de facto unviable since they are confined within the extremely hard pericarp of aborted fruits, which prevents any seedling emergence and thus any contribution to tree recruitment. We show that only when rodents partially gnaw the pericarp walls of aborted fruits, seeds that escaped from predation have the prospect of emerging and thus potentially contributing to tree regeneration. Thus, in this and probably in many other similar synzoochore systems, rodents act as rescuers of seeds confined within aborted fruits, conferring the plants a largely overlooked benefit that could shape the reproductive strategy of many plant species

Contemporary defaunation has profound ecological consequences ranging from local or even global co-extinctions of interacting species to the loss of ecosystem functions and services critical for humanity. Other components of global change (climate change, introduced pests, land use changes) are also harming ecosystem functioning by augmenting tree mortality worldwide. Defaunation and increased tree mortality often coincide in many human-altered ecosystems but whether they interact, leading to non-additive effects on ecosystem functioning, remains largely unknown. However, under some ecological circumstances, the decline or extirpation of one species due to defaunation can be neutralized by increases in the abundance of some functionally similar species (i.e. ‘density compensation’). We combined long-term field data with individual-based modelling to investigate the potential interactive effects of seed disperser loss, increased tree mortality and density compensation on seed dispersal in a heterogeneous landscape. Our simulation experiments showed that both stressors markedly limit not only the quantity of seed dispersal but also its quality since the impact on seed dispersal strongly varied among habitat types that differ strikingly in suitability for tree establishment. Density compensation had a marked positive effect on seed dispersal which, however, was largely limited under increased tree mortality. The combined negative effects of defaunation and increased tree mortality on seed dispersal were lower than the expected additive effect. This highlights the need to account for the joint operation of multiple stressors to accurately predict the impacts of global change on the link between biodiversity and ecosystem functioning