Although one-quarter of plant and vertebrate species are threatened with extinction, little is known about the potential effect of extinctions on the global diversity of ecological strategies. Using trait and phylogenetic information for more than 75,000 species of vascular plants, mammals, birds, reptiles, amphibians, and freshwater fish, we characterized the global functional spectra of each of these groups. Mapping extinction risk within these spectra showed that larger species with slower pace of life are universally threatened. Simulated extinction scenarios exposed extensive internal reorganizations in the global functional spectra, which were larger than expected by chance for all groups, and particularly severe for mammals and amphibians. Considering the disproportionate importance of the largest species for ecological processes, our results emphasize the importance of actions to prevent the extinction of the megabiota.

AbstractIn times of global biodiversity crisis, developing tools to define, quantify, compare and predict ecological resilience is essential for understanding species’ responses to global change. Disparate interpretations of ecological resilience have, however, hampered the development of a common currency to quantify and compare resilience across natural systems. Most frameworks of study have focused on upper levels of biological organisation, especially ecosystems or communities, which adds layers of complication to measuring resilience with empirical data. To overcome such limitations, we suggest quantifying resilience using demographic data. Surprisingly, a quantifiable definition of resilience does not exist at the demographic level. Here, we present a framework of demographic resilience with a set of metrics that are comparable across species, and facilitate cost-effective management decisions.

In the current global biodiversity crisis, the development of tools to define, quantify, compare, and predict resilience is essential for understanding the responses of species to global change. However, disparate interpretations of resilience have hampered the development of a common currency to quantify and compare resilience across natural systems. Most resilience frameworks focus on upper levels of biological organization, especially ecosystems or communities, which complicates measurements of resilience using empirical data. Surprisingly, there is no quantifiable definition of resilience at the demographic level. We introduce a framework of demographic resilience that draws on existing concepts from community and population ecology, as well as an accompanying set of metrics that are comparable across species. Resilience as a Key Concept in Ecology and ConservationContemporary global change is increasingly eroding natural resources [1-3]. Thus, understanding how ecological systems withstand environmental disturbances (see Glossary) is a major challenge [4][5][6]. 'Resilience' is a key concept that describes the ability of natural systems to handle disturbances [7]. Indeed, international environmental policy objectives, including the UN Sustainable Development Goals [8] and Aichi Targets [9], specifically include preserving resilience as a key objective.Resilience describes the ability of a system to resist and recover from a disturbance [10]. However, translating resilience into quantifiable metrics is challenging due to the complexities of ecological systems [11], and has generated multiple debates over the past decades regarding its definition, meaning, and application [10,12,13] (Box 1). Discrepancies between approaches mean that both theoretical and empirical works lack parity between the primary components of resilience studied, rendering comparisons challenging if not impossible. These limitations ultimately prevent ecologists from applying resilience-based solutions to real-world problems (e.g., [14]). Developing a unifying framework with comparable definitions and quantifications across different ecological systems is therefore an urgent task [10,15,16].We introduce a framework to define, quantify, and compare resilience across populations and species. The framework integrates resilience concepts from community ecology [10,15,17,18] and demographic theory [19]. Following the conceptualizations of resilience in Hodgson et al.[10], we define demographic resilience as the ability of populations to resist and recover (Box 1) from alterations in their demographic structure, usually with concomitant change in population size. We show that transient dynamics, as extensively described in [20,21], can be used to quantify demographic resilience and to anticipate the responses of the population and of species to disturbances. Thus, our framework marries two disciplines to define and quantify demographic resilience, and includes elements that draw from and are analogous to community resilience [11,22].

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Climate change is causing an increase in the frequency and intensity of marine heatwaves (MHWs) and mass mortality events (MMEs) of marine organisms are one of their main ecological impacts. Here, we show that during the 2015-2019 period, the Mediterranean Sea has experienced exceptional thermal conditions resulting in the onset of five consecutive years of widespread MMEs across the basin. These MMEs affected thousands of kilometers of coastline from the surface to 45 m, across a range of marine habitats and taxa (50 taxa across 8 phyla). Significant relationships were found between the incidence of MMEs and the heat exposure associated with MHWs observed both at the surface and across depths. Our findings reveal that the Mediterranean Sea is experiencing an acceleration of the ecological impacts of MHWs which poses an unprecedented threat to its ecosystems' health and functioning.

Nicole M. van Dam and Roberto Salguero-Gómez joint last authorship.

Patterns of ageing across the tree of life are much more diverse than previously thought. Yet, we still do not adequately understand how, why and where across the tree of life a particular pattern of ageing will evolve. An ability to predict ageing patterns requires a firmer understanding of how and why different ecological and evolutionary factors alter the sensitivity of fitness to age-related changes in mortality and reproduction. From this understanding, we can ask why and where selection gradients might not decline with age. Here, we begin by summarizing the recent breadth of literature that is unearthing, empirically and theoretically, the mechanisms that drive variation in patters of senescence. We focus on the relevance of two key parameters, population structure and reproductive value, as key to understanding selection gradients, and therefore senescence. We discuss how growth form, individual trade-offs, stage structure and social interactions may all facilitate differing distributions of these two key parameters than those predicted by classical theory. We argue that these four key aspects can help us understand why patterns of negligible and negative senescence can actually be explained under the same evolutionary framework as classical senescence.

Preventing biodiversity loss in the face of global change is a major challenge in ecology and conservation (Folke et al., 2004;Scheffer et al., 2012). As global change accelerates (Hoegh-Guldberg et al., 2018), species-and the services that they provide (Pecl et al., 2017)-are being lost at an unprecedented rate (Barnosky et al., 2012;Pimm et al., 2014). Still, some species can persist or even increase their abundance despite the increasingly frequent and intense disturbance events, as a consequence of global change (Antão et al., 2020;Blowes et al., 2019;van Klink et al., 2020). Such an ability to persist after a disturbance depends, to a large extent, on the species' inherent ability to resist and recover from such events, their resilience (Capdevila, Stott, et al., 2020;Hodgson et al., 2015). Therefore, understanding what makes some species more/less resilient than others is crucial to developing effective management and conservation plans (Pressey et al., 2007). Yet, the lack of data regarding species' natural population's responses to disturbances and robust methods to quantify resilience have hampered