Browsing by Subject "EXTINCTION RISK"

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  • Henriques, Sérgio; Böhm, Monika; Collen, Ben; Luedtke, Jennifer; Hoffmann, Michael; Hilton-Taylor, Craig; Cardoso, Pedro; Butchart, Stuart H. M.; Freeman, Robin (2020)
    Abstract Given the current biodiversity crisis, pragmatic approaches to detect global conservation trends across a broad range of taxa are critical. A sampled approach to the Red List Index (RLI) was proposed, as many groups are highly speciose. However, a decade after its conception, the recommended 900 species sample has only been implemented in six groups and trend data are available for none, potentially because this sample is unfeasibly high. Using a broader set of all available data we show that when re-assessments are conducted every 10 years, 200 species (400 in some cases) should be sufficient to detect a RLI trend. Correctly detecting changes in slope still requires samples of 900 species (11,000 in some cases). Sampled assessments can accelerate biodiversity monitoring and complement current metrics, but the time-period between assessments and the approaches? purpose should be carefully considered, as there is a trade-off between sample size and the resulting indices.
  • Antao, Laura; Weigel, Benjamin; Strona, Giovanni; Hällfors, Maria; Kaarlejärvi, Elina; Dallas, Tad; Opedal, Øystein; Heliölä, Janne; Henttonen, Heikki; Huitu, Otso; Korpimäki, Erkki; Kuussaari, Mikko; Lehikoinen, Aleksi; Leinonen, Reima; Lindén, Andreas; Merilä, Päivi; Pietiäinen, Hannu; Pöyry, Juha; Salemaa, Maija; Tonteri, Tiina; Vuorio, Kristiina; Ovaskainen, Otso; Saastamoinen, Marjo; Vanhatalo, Jarno; Roslin, Tomas; Laine, Anna-Liisa (2022)
    Climate change is a pervasive threat to biodiversity. While range shifts are a known consequence of climate warming contributing to regional community change, less is known about how species’ positions shift within their climatic niches. Furthermore, whether the relative importance of different climatic variables prompting such shifts varies with changing climate remains unclear. Here we analysed four decades of data for 1,478 species of birds, mammals, butterflies, moths, plants and phytoplankton along a 1,200 km high latitudinal gradient. The relative importance of climatic drivers varied non-uniformly with progressing climate change. While species turnover among decades was limited, the relative position of species within their climatic niche shifted substantially. A greater proportion of species responded to climatic change at higher latitudes, where changes were stronger. These diverging climate imprints restructure a full biome, making it difficult to generalize biodiversity responses and raising concerns about ecosystem integrity in the face of accelerating climate change.
  • Lucena-Moya, Paloma; Gascon, Stephanie; Boix, Daniel; Pardo, Isabel; Sala, Jordi; Quintana, Xavier D. (2017)
    The present study compared crustacean assemblages from coastal wetlands between a fragment archipelago and a landmass. The study included four typical crustacean taxonomic groups (i.e. Cladocera, Copepoda, Ostracoda and Malacostraca) from the Balearic Archipelago region as an example of a fragment island (Archipelago') and the Catalonia region as the landmass (Mainland'; Spanish Mediterranean coast). We tested null hypotheses based on the expected similarity between Archipelago and Mainland in terms of crustacean assemblages and biodiversity. Similar relationships of those community attributes with environmental variables were also expected in both regions. The results partially met the null hypotheses. We found that crustacean taxonomic composition varied between Archipelago and Mainland, likely due to peculiar biological and biogeographical processes acting in the Archipelago. The relationship between crustacean assemblages and the environmental variables was mostly similar between Archipelago and Mainland, as expected. Both regions also showed similar patterns of species distribution (i.e. Archipelago and Mainland coastal wetlands were characterised by a few dominant species). This result could be masked by the filter' effect exercised by the harsh conditions of coastal wetlands. Moreover, the total diversity values (gamma biodiversity) in the Archipelago were similar to the values for the Mainland, supporting the hypothesis that fragment islands can be of substantial value for the conservation of global biodiversity.
  • Milicic, Marija; Vujic, Ante; Cardoso, Pedro (2018)
    Climate change presents a serious threat to global biodiversity. Loss of pollinators in particular has major implications, with extirpation of these species potentially leading to severe losses in agriculture and, thus, economic losses. In this study, we forecast the effects of climate change on the distribution of hoverflies in Southeast Europe using species distribution modelling and climate change scenarios for two time-periods. For 2041-2060, 19 analysed species were predicted to increase their areas of occupancy, with the other 25 losing some of their ranges. For 2061-2080, 55% of species were predicted to increase their area of occupancy, while 45% were predicted to experience range decline. In general, range size changes for most species were below 20%, indicating a relatively high resilience of hoverflies to climate change when only environmental variables are considered. Additionally, range-restricted species are not predicted to lose more area proportionally to widespread species. Based on our results, two distributional trends can be established: the predicted gain of species in alpine regions, and future loss of species from lowland areas. Considering that the loss of pollinators from present lowland agricultural areas is predicted and that habitat degradation presents a threat to possible range expansion of hoverflies in the future, developing conservation management strategy for the preservation of these species is crucial. This study represents an important step towards the assessment of the effects of climate changes on hoverflies and can be a valuable asset in creating future conservation plan, thus helping in mitigating potential consequences.
  • Sandal, Lisa; Grotan, Vidar; Saether, Bernt-Erik; Freckleton, Robert P.; Noble, David G.; Ovaskainen, Otso (2022)
    Our knowledge of the factors affecting species abundances is mainly based on time-series analyses of a few well-studied species at single or few localities, but we know little about whether results from such analyses can be extrapolated to the community level. We apply a joint species distribution model to long-term time-series data on British bird communities to examine the relative contribution of intra- and interspecific density dependence at different spatial scales, as well as the influence of environmental stochasticity, to spatiotemporal interspecific variation in abundance. Intraspecific density dependence has the major structuring effect on these bird communities. In addition, environmental fluctuations affect spatiotemporal differences in abundance. In contrast, species interactions had a minor impact on variation in abundance. Thus, important drivers of single-species dynamics are also strongly affecting dynamics of communities in time and space.
  • Buechley, Evan R.; Santangeli, Andrea; Girardello, Marco; Neate-Clegg, Montague H.C.; Oleyar, Dave; McClure, Christopher J.W.; Şekercioğlu, Çagan H. (2019)
    Abstract Aim Raptors serve critical ecological functions, are particularly extinction-prone and are often used as environmental indicators and flagship species. Yet, there is no global framework to prioritize research and conservation actions on them. We identify for the first time the factors driving extinction risk and scientific attention on raptors and develop a novel research and conservation priority index (RCPI) to identify global research and conservation priorities. Location Global. Methods We use random forest models based on ecological traits and extrinsic data to identify the drivers of risk and scientific attention in all raptors. We then map global research and conservation priorities. Lastly, we model where priorities fall relative to country-level human social indicators. Results Raptors with small geographic ranges, scavengers, forest-dependent species and those with slow life histories are particularly extinction-prone. Research is extremely biased towards a small fraction of raptor species: 10 species (1.8% of all raptors) account for one-third of all research, while one-fifth of species have no publications. Species with small geographic ranges and those inhabiting less developed countries are greatly understudied. Regions of Latin America, Africa and Southeast Asia are identified as particularly high priority for raptor research and conservation. These priorities are highly concentrated in developing countries, indicating a global mismatch between priorities and capacity for research and conservation. Main conclusions A redistribution of scientific attention and conservation efforts towards developing tropical countries and the least-studied, extinction-prone species is critical to conserve raptors and their ecological functions worldwide. We identify clear taxonomic and geographic research and conservation priorities for all raptors, and our methodology can be applied across other taxa to prioritize scientific investment.
  • Niskanen, Annina Kaisa Johanna; Niittynen, Pekka; Aalto, Juha; Väre, Henry; Luoto, Miska (2019)
    Aim: Species' biogeographical patterns are already being altered by climate change. Here, we provide predictions of the impacts of a changing climate on species' geographical ranges within high-latitude mountain flora on a sub-continental scale. We then examined the forecasted changes in relation to species' biogeographic histories. Location: Fennoscandia, Northern Europe (55-72 degrees N). Methods: We examined the sensitivity of 164 high-latitude mountain species to changing climate by modelling their distributions in regard to climate, local topography and geology at a 1 km(2) resolution. Using an ensemble of six statistical modelling techniques and data on current (1981-2010) and future (2070-2099) climate based on three Representative Concentration Pathways (RCPs 2.6, 4.5, 8.5), we developed projections of current and future ranges. Results: The average species richness of the mountain flora is predicted to decrease by 15%-47% per 1 km(2) cell, depending on the climate scenario considered. Arctic flora is projected to undergo severe range loss along with non-poleward range contractions, while alpine flora is forecasted to find suitable habitat in a warmer North. A substantial majority (71%-92%) of the studied species are projected to lose more than half of their present range by the year 2100. Species predicted to lose all suitable habitat had ranges centred in the northernmost (>68 degrees N) part of continental Europe. Main conclusions: Climate change is predicted to substantially diminish the extent and richness of Europe's high-latitude mountain flora. Interestingly, species' biogeographic histories affect their vulnerability to climate change. The vulnerability of true Arctic and endemic species marks them as highly important for conservation decisions.
  • Wang, Yingying X. G.; Matson, Kevin D.; Santini, Luca; Visconti, Piero; Hilbers, Jelle P.; Huijbregts, Mark A. J.; Xu, Yanjie; Prins, Herbert H. T.; Allen, Toph; Huang, Zheng Y. X.; de Boer, Willem F. (2021)
    As a source of emerging infectious diseases, wildlife assemblages (and related spatial patterns) must be quantitatively assessed to help identify high-risk locations. Previous assessments have largely focussed on the distributions of individual species; however, transmission dynamics are expected to depend on assemblage composition. Moreover, disease-diversity relationships have mainly been studied in the context of species loss, but assemblage composition and disease risk (e.g. infection prevalence in wildlife assemblages) can change without extinction. Based on the predicted distributions and abundances of 4466 mammal species, we estimated global patterns of disease risk through the calculation of the community-level basic reproductive ratio R0, an index of invasion potential, persistence, and maximum prevalence of a pathogen in a wildlife assemblage. For density-dependent diseases, we found that, in addition to tropical areas which are commonly viewed as infectious disease hotspots, northern temperate latitudes included high-risk areas. We also forecasted the effects of climate change and habitat loss from 2015 to 2035. Over this period, many local assemblages showed no net loss of species richness, but the assemblage composition (i.e. the mix of species and their abundances) changed considerably. Simultaneously, most areas experienced a decreased risk of density-dependent diseases but an increased risk of frequency-dependent diseases. We further explored the factors driving these changes in disease risk. Our results suggest that biodiversity and changes therein jointly influence disease risk. Understanding these changes and their drivers and ultimately identifying emerging infectious disease hotspots can help health officials prioritize resource distribution.
  • Garcia, Raquel A.; Araujo, Miguel B.; Burgess, Neil D.; Foden, Wendy B.; Gutsche, Alexander; Rahbek, Carsten; Cabeza, Mar (2014)
  • Popov, S.; Milicic, M.; Diti, I.; Marko, O.; Sommaggio, D.; Markov, Z.; Vujic, A. (2017)
    Spatial and temporal differences in landscape patterns are of considerable interest for understanding ecological processes. In this study, we assessed habitat quality by using the Syrph The Net database and data on decreasing species richness over a 25-year period for the two largest phytophagous hoverfly genera (Merodon and Cheilosia). Furthermore, within this time frame, we explored congruence between ecological responses (species richness and Biodiversity Maintenance Function for these two genera) and landscape structural changes through correlation analysis. Our results indicate that landscapes have experienced changes in aggregation, isolation/connectivity and landscape diversity, with these parameters being significantly correlated with Cheilosia species richness loss and habitat quality. We conclude that the genus Cheilosia is a good bioindicator that can highlight not only the current quality of an area but also temporal changes in landscape patterns.
  • Llewelyn, John; Strona, Giovanni; McDowell, Matthew C.; Johnson, Christopher N.; Peters, Katharina J.; Stouffer, Daniel B.; de Visser, Sara N.; Saltre, Frederik; Bradshaw, Corey J. A. (2022)
    Extinctions stemming from environmental change often trigger trophic cascades and coextinctions. Bottom-up cascades occur when changes in the primary producers in a network elicit flow-on effects to higher trophic levels. However, it remains unclear what determines a species' vulnerability to bottom-up cascades and whether such cascades were a large contributor to the megafauna extinctions that swept across several continents in the Late Pleistocene. The pathways to megafauna extinctions are particularly unclear for Sahul (landmass comprising Australia and New Guinea), where extinctions happened earlier than on other continents. We investigated the potential role of bottom-up trophic cascades in the megafauna extinctions in Late Pleistocene Sahul by first developing synthetic networks that varied in topology to identify how network position (trophic level, diet breadth, basal connections) influences vulnerability to bottom-up cascades. We then constructed pre-extinction (-80 ka) network models of the ecological community of Naracoorte, south-eastern Sahul, to assess whether the observed megafauna extinctions could be explained by bottom-up cascades. Synthetic networks showed that node vulnerability to bottom-up cascades decreased with increasing trophic level, diet breadth and basal connections. Extinct species in the Naracoorte community were more vulnerable overall to these cascades than were species that survived. The position of extinct species in the network - tending to be of low trophic level and therefore having relatively narrow diet breadths and fewer connections to plants - made them vulnerable. However, these species also tended to have few or no predators, a network-position attribute that suggests they might have been particularly vulnerable to new predators. Together, these results suggest that trophic cascades and naivety to predators could have contributed to the megafauna extinction event in Sahul.
  • Nonaka, Etsuko; Sirén, Jukka; Somervuo, Panu; Ruokolainen, Lasse; Ovaskainen, Otso; Hanski, Ilkka (2019)
    Abstract Inbreeding is common in nature, and many laboratory studies have documented that inbreeding depression can reduce the fitness of individuals. Demonstrating the consequences of inbreeding depression on the growth and persistence of populations is more challenging because populations are often regulated by density- or frequency-dependent selection and influenced by demographic and environmental stochasticity. A few empirical studies have shown that inbreeding depression can increase extinction risk of local populations. The importance of inbreeding depression at the metapopulation level has been conjectured based on population-level studies but has not been evaluated. We quantified the impact of inbreeding depression affecting the fitness of individuals on metapopulation persistence in heterogeneous habitat networks of different sizes and habitat configuration in a context of natural butterfly metapopulations. We developed a spatial individual-based simulation model of metapopulations with explicit genetics. We used Approximate Bayesian Computation to fit the model to extensive demographic, genetic, and life-history data available for the well-studied Glanville fritillary butterfly (Melitaea cinxia) metapopulations in the Åland islands in SW Finland. We compared 18 semi-independent habitat networks differing in size and fragmentation. The results show that inbreeding is more frequent in small habitat networks, and consequently, inbreeding depression elevates extinction risks in small metapopulations. Metapopulation persistence and neutral genetic diversity maintained in the metapopulations increase with the total habitat amount in and mean patch size of habitat networks. Dispersal and mating behavior interact with landscape structure to determine how likely it is to encounter kin while looking for mates. Inbreeding depression can decrease the viability of small metapopulations even when they are strongly influenced by stochastic extinction-colonization dynamics and density-dependent selection. The findings from this study support that genetic factors, in addition to demographic factors, can contribute to extinctions of small local populations and also of metapopulations. This article is protected by copyright. All rights reserved.
  • Ranta, Pertti; Jokinen, Ari; Laaka-Lindberg, Sanna (2016)
    Building strategies for continental-scale conservation is challenging due to evolutionary and geopolitical problems. How do policy choices arise from this setting? In this study, we integrate ecological research with policy analysis to examine the problem field with a case study research. We use a violet species endemic to Europe, Viola uliginosa, as a proxy for a significant European Union (EU)-Russian biodiversity pattern and its conservation. The violet's core populations locate in Belarus, Ukraine, and Russia, and all populations in the EU are peripheral. The species is endangered in 12 EU member states and in decline in many places elsewhere. To analyze the choices of conservation, we gathered data on its ecology, distribution, and conservation mechanisms across Europe, putting additional emphasis on the EU enlargement and long-term site histories in Finland. We found that the survival of the species in the EU depends on the enlargement negotiations, conflicts between the EU biodiversity and agricultural policies, selection of the species to national Red Lists and the Habitats Directive, and contingent site histories depending on the conservation activities by civic actors and the member states. While the evolutionary aspect emphasizes the genetic differentiation potential of peripheral populations, the geopolitical aspect characterizes the EU as simultaneous spaces of a monotopia, borderlands, and polycentric development. We conclude that intersections between these geopolitical spaces can be used with evolutionary perspectives to identify local, European, and network-driven policy choices of conservation.
  • Baur, Julian; Jagusch, Dorian; Michalak, Piotr; Koppik, Mareike; Berger, David (2022)
    To mitigate the effects of climate change, it is important to understand species' responses to increasing temperatures. This has often been done by studying survival or activity at temperature extremes. Before such extremes are reached, however, effects on fertility may already be apparent. Sex differences in the thermal sensitivity of fertility (TSF) could impact species persistence under climate warming because female fertility is typically more limiting to population growth than male fertility. However, little is known about sex differences in TSF. Here we first demonstrate that the mating system can strongly influence TSF using the seed beetle Callosobruchus maculatus. We exposed populations carrying artificially induced mutations to two generations of short-term experimental evolution under alternative mating systems, manipulating the opportunity for natural and sexual selection on the mutations. We then measured TSF in males and females subjected to juvenile or adult heat stress. Populations kept under natural and sexual selection had higher fitness, but similar TSF, compared to control populations kept under relaxed selection. However, females had higher TSF than males, and strikingly, this sex difference had increased over only two generations in populations evolving under sexual selection. We hypothesized that an increase in male-induced harm to females during mating had played a central role in driving this evolved sex difference, and indeed, remating under conditions limiting male harassment of females reduced both male and female TSF. Moreover, we show that manipulation of mating system parameters in C. maculatus generates intraspecific variation in the sex difference in TSF equal to that found among a diverse set of studies on insects. Our study provides a causal link between the mating system and TSF. Sexual conflict, (re)mating rates and genetic responses to sexual selection differ among ecological settings, mating systems and species. Our study therefore also provides mechanistic understanding for the variability in previously reported TSFs which can inform future experimental assays and predictions of species responses to climate warming. A free Plain Language Summary can be found within the Supporting Information of this article.
  • Herrando, Sergi; Keller, Verena; Bauer, Hans-Guenther; Brotons, Lluis; Eaton, Mark; Kalyakin, Mikhail; Voltzit, Olga; Lehikoinen, Aleksi; Milanesi, Pietro; Noble, David; Ramirez, Ivan; Vorisek, Petr; Foppen, Ruud (2019)
    Capsule The first European Bird Census Council (EBCC) Atlas of European Breeding Birds has been widely used in scientific publications. Aims To quantify how scientific publications have used data from the first European Bird Census Council (EBCC) Atlas of European Breeding Birds, what the topics of these studies have been, and to identify key aspects in which a second European Breeding Bird Atlas will provide new opportunities for basic and applied science. Methods We searched Google Scholar to find papers published in scientific journals that cited the first atlas. We analysed the contents of a random selection of 100 papers citing this atlas and described the way these papers used information from it. Results The first atlas has been cited in 3150 scientific publications, and can be regarded as a fundamental reference for studies about birds in Europe. It was extensively used as a key reference for the studied bird species. A substantial number of papers re-analysed atlas data to derive new information on species distribution, ecological traits and population sizes. Distribution and ecology were the most frequent topics of studies referring to the atlas, but this source of information was used in a diverse range of studies. In this context, climate change, impact of agriculture and habitat loss were, by order, the most frequently studied environmental pressures. Constraints in the atlas, such as the poor coverage in the east of Europe, the lack of information on distribution change and the coarse resolution were identified as issues limiting the use of the atlas for some purposes. Conclusions This study demonstrates the scientific value of European-wide breeding bird atlases. A second atlas, with its almost complete coverage across Europe, the incorporation of changes in distribution between the two atlases and the inclusion of modelled maps at a resolution of 10 x 10 km will certainly become a key data source and reference for researchers in the near future.