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As the number of introduced species keeps increasing unabatedly, identifying and prioritising current and potential Invasive Alien Species (IAS) has become essential to manage them. Horizon Scanning (HS), defined as an exploration of potential threats, is considered a fundamental component of IAS management. By combining scientific knowledge on taxa with expert opinion, we identified the most relevant aquatic IAS in the Iberian Peninsula, i.e., those with the greatest geographic extent (or probability of introduction), severe ecological, economic and human health impacts, greatest difficulty and acceptability of management. We highlighted the 126 most relevant IAS already present in Iberian inland waters (i.e., Concern list) and 89 with a high probability of being introduced in the near future (i.e., Alert list), of which 24 and 10 IAS, respectively, were considered as a management priority after receiving the highest scores in the expert assessment (i.e., top-ranked IAS). In both lists, aquatic IAS belonging to the four thematic groups (plants, freshwater invertebrates, estuarine invertebrates, and vertebrates) were identified as having been introduced through various pathways from different regions of the world and classified according to their main functional feeding groups. Also, the latest update of the list of IAS of Union concern pursuant to Regulation (EU) No 1143/2014 includes only 12 top-ranked IAS identified for the Iberian Peninsula, while the national lists incorporate the vast majority of them. This fact underlines the great importance of taxa prioritisation exercises at biogeographical scales as a step prior to risk analyses and their inclusion in national lists. This HS provides a robust assessment and a cost-effective strategy for decision-makers and stakeholders to prioritise the use of limited resources for IAS prevention and management. Although applied at a transnational level in a European biodiversity hotspot, this approach is designed for potential application at any geographical or administrative scale, including the continental one., This research was supported by the LIFE INVASAQUA project (Aquatic In- vasive Alien Species of Freshwater and Estuarine Systems: Awareness and Prevention in the Iberian Peninsula) (LIFE17 GIE/ES/000515) funded by the EU LIFE Program. The Fundación Biodiversidad (Government of Spain) and the Government of Navarre financially support specific actions into the LIFE INVASAQUA. F.R. is supported by Foundation for Science and Technology through an individual contract (CEEC/0482/2020). J.E. has a Ph.D. scholarship (SFRH/BD/140556/2018) funded by FCT, Portugal. F.B. is supported by Foundation for Science and Technology through an individual contract (CEEC/01896/2021).

The conservation of biodiversity is a central imperative of the 21st century. Subterranean ecosystems deliver critical nature’s contributions to people and harbour a broad diversity of poorly-understood specialized organisms that are of interest from both a conservation and evolutionary perspective. However, the subterranean biome is still systematically overlooked in global biodiversity targets and conservation agendas. The main objective of this study was to assess how far subterranean biodiversity is represented in protected areas (Natura 2000 and Emerald networks) in two global hotspots of subterranean biodiversity (the Pyrenees and the Alps). For this, we used the most complete databases of terrestrial subterranean biodiversity known to us, i.e., leiodids (beetles) from the Pyrenees and spiders from the Alps, and identified priority areas in each region using both species richness and geographic rarity patterns. Our results show the incapacity of surface protected area networks to represent subterranean fauna, as more than 70 and 90% of the identified priority areas (and the 40 and 22% of the species) are not effectively covered by protected areas in the Pyrenees and the Alps, respectively. These findings call for urgent policies and would be key to developing a coherent plan for subterranean biodiversity conservation within the European Biodiversity Strategy for 2030.

Physiological traits are key in determining the vulnerability of narrow range, highly specialized animals to climate change. It is generally predicted that species from more stable environments possess lower thermal tolerance breadths and thermal plasticity than those from more variable habitats – the so-called ‘climatic variability hypothesis’. However, evolutionary trade-offs between thermal breadth and its plasticity are also seen in some taxa, and the evolution of thermal physiology remains poorly understood. Subterranean environments are excellent systems for exploring these issues, being characterized by stable climatic conditions, with environmental variability increasing predictably from deep to shallow habitats. Acclimation capacity will be fundamental in determining the sensitivity of subterranean species to climate change, since they have poor dispersal capacity and limited possibility to exploit thermally different microhabitats in the uniform cave environment. We assessed critical thermal maximum (CT) and short-term heat acclimation capacity in three related beetles (Leiodidae: Leptodirini) with differing degrees of specialization to the subterranean environment (deep, shallow and facultatively subterranean, respectively) and therefore exposed to contrasting thermal variability in nature. Only the facultative subterranean species showed any acclimatory capacity, also having the highest CT across the taxa studied. However, this species might experience the highest thermal stress in its habitat under climate change. The studied subterranean specialists will be poorly able to cope physiologically with temperature increase, but in contrast exposed to lower magnitude and rate of warming. Our results fit the climatic variability hypothesis, suggesting that adaptation to cave conditions has selected against the retention of acclimation mechanisms. We show that the pathways that determine vulnerability of subterranean species to climate change depend on their degree of specialization to deep subterranean environments. This information, combined with evaluation of exposure to climatic changes at their present locations, is fundamental in identifying species or populations at greatest risk., This work was supported by the Agencia Estatal de Investigación (Spain), the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund (project CGL2016-76995-P). S.P is funded by a postdoctoral grant from Fundación Séneca - Agencia de Ciencia y Tecnología de la Región de Murcia (Spain). D. S-F and M. B-C are funded by a postdoctoral and predoctoral grant from the University of Murcia (Spain) respectively. R.C and P. B-G are funded by predoctoral grants of the Spanish Ministry of Science, Innovation and Universities.

Evaluating data quality and inventory completeness must be a preliminary step inany biodiversity research, particularly in the case of insects and high biodiversityareas. Yet, this step is often neglected or, at best, assessed only for one insectgroup, and the degree of congruence of sampling effort ffor different insect groupsremains unexplored. We assess the congruence in the spatial distribution of sampling effort for fiveinsect groups (butterflies, caddisflies, dung beetles, moths, and aquatic beetles) inthe Iberian Peninsula. We identify well-surveyed areas for each taxonomic groupand examine the degree to which the patterns of sampling effort can be explainedby a set of variables related to environmental conditions and accessibility. Irrespective of the general lack of reliable inventories, we found a general but lowcongruence in the completeness patterns of the different taxa. This suggests thatthere is not a common geographical pattern in survey effort and that idiosyncraticand contingent factors (mainly the proximity to the workplaces of entomologists)are differentially affecting each group. After many decades of taxonomic and faunistic work, distributional databases ofIberian insects are still in a very preliminary stage, thus limiting our capacity toobtain reliable answers to basic and applied questions. We recommend carrying out long-term, standardised and well-designed entomolog-ical surveys able to generate a reliable image of the distribution of different insect groups. This will allow us to estimate accurately insect trends and better under-stand the full extent of global biodiversity loss., This study has been supported by the projects BioWeb (MINECO:CGL2011-15622-E BOS), BANDENCO (JCMM: POII11-0277-5747)and IBERARTRO (SBPLY/17/180501/000492) founded by European Regional Development Fund (ERDF) through the Consejería de Educación, Ciencia y Cultura, Junta de Comunidades de Castilla-La Mancha. David Sánchez-Fernández is funded by a postdoctoral contract fromthe Spanish Ministry of Science and Innovation (Ramón y Cajal program; RYC2019-027446-I

info:eu-repo/semantics/publishedVersion

Coping with aridity is a physiological challenge for all organisms, including fresh-water ones. Aridity shapes distributions of aquatic species at fine and large geo-graphical scales. Specifically, for aquatic beetles, the desiccation resistance of the adults is a potential constraint for the colonisation of arid regions. We assessed the congruence between the fundamental and realised aridity niche in eight species of a Palearctic lineage of water beetles (subgenus Lumetus, genus Enochrus, family Hydrophilidae). We also estimated the relative explanatory capacity of aridity-related versus other environmental variables in species distributions. Most of the species, even those most sensitive to desiccation stress in laboratory experiments, occur in areas with high aridity within the Palearctic region. Our results suggest a lack of association between the physiological (desiccation resistance) and environmental distance matrix (realised aridity niche), or between either of these and phylogenetic distances. Aridity-related variables had generally a similar explanatory capacity in explaining the distribution of species than non-related ones. Our results indicate that desiccation resistance has not been an important physiological constraint for the colonisation of arid environments by this clade and suggest that other non-physiological factors are more important in shaping their distributions along aridity gradients. The studied beetle lineage might conserve a high basal desiccation resistance from relatively recent terrestrial ancestors, which could have provided a physiological advantage for the colonisation of arid areas. Further research could shed light on whether these unexpected results are common to other groups of aquatic insects living in arid areas or are particular to this group of beetles., Part of this work was funded by the project CGL2013-48950-C2-1&2-P from the Agencia Estatal de Investigación (AEI) of Spain and the European Regional Development Fund (FEDER, EU). S.P. and D.S.-F. are funded by postdoctoral contracts from the Spanish Ministry of Science and Innovation (Juan de la Cierva-Formación, FJC2018-035577-I and Ramón y Cajal, RYC2019-027446-I programmes, respectively).

[EN] Freshwater ecosystems are exposed to an increasing number of stressors, challenging their biomonitoring and management. Despite recent advances in multiple-stressor research, regional-scale assessments in areas with high freshwater biodiversity and increasing anthropogenic pressure are urgently needed. We reviewed 61 studies focused on freshwater individuals, populations and communities from the Iberian Peninsula to (i) quantify the frequency of experimental approaches used (manipulative, observational), aquatic systems, biological organization levels, and types of organisms and modelled responses, (ii) identify key individual stressors and the frequency of significant positive (increase in response magnitude) and negative (decrease) effects and (iii) determine types of interacting stressors and the frequency of their combined effects. Our dataset comprised 409 unique responses to 13 types of individual stressors, 34 stressor pairs and 12 high-order interactions (3- and 4-way). We found a higher prevalence of manipulative (85 %) respect to observational studies, and a greater focus on lotic systems (59 %) and heterotrophic organisms (58 %). The most studied stressors were nutrient (Nutr), thermal (Therm), hydrologic (Hydr), ultraviolet radiation (UVR), toxic (Toxic) and salinity (Sal) stress and land-use pressure. Individual stressors showed a higher proportion of negative (34 %) than positive effects (26 %). Nutr × UVR, Toxic × Toxic, Therm × Toxic, Hydr × Toxic, Sal × Therm, and Nutr × Therm were the most studied stressor pairs. Non-interactive (50 %) and interactive responses (50 %) were balanced. Antagonistic effects (18 %) were slightly more common than synergisms (15 %), reversal or opposing. (13 %) and high-order interactions (4 %). Such proportions varied within experimental approaches, biological organization levels and organism types. Our findings are helpful to manage certain stressor combinations in Iberian freshwaters. Further efforts in Iberian multiple-stressor research should be directed to (i) intensify the study of lentic systems, (ii) explore more observational data, (iii) autotrophic organisms and (vi) biodiversity-ecosystem functioning responses, and (v) cover a wider range of stressors and (vi) more complex interacting stressor scenarios., [ES] Los ecosistemas acuáticos continentales están expuestos a un creciente número de factores de estrés, lo que supone un reto para su monitoreo y gestión. A pesar de los recientes avances en el estudio de estresores múltiples a nivel global, resulta también necesario evaluar áreas que concentran una alta biodiversidad acuática y que están expuestas a una elevada presión antrópica. En esta revisión hemos examinado 61 estudios basados en individuos, poblaciones y comunidades de ecosistemas acuáticos continentales ibéricos para (i) cuantificar la frecuencia de la aproximación experimental usada (estudio manipulativo u observacional), el tipo de sistema acuático, niveles de organización biológica, tipos de organismos y de respuestas abarcadas, (ii) identificar estresores clave y la frecuencia de efectos positivos (aumento de magnitud de la respuesta) y negativos (descenso) y (iii) determinar las combinaciones de factores estudiados y la frecuencia de sus efectos combinados. Los estudios revisados incluyen 409 respuestas, 13 estresores individuales, 34 pares de estresores y 12 interacciones de orden superior (3er y 4º orden). Encontramos una mayor frecuencia de estudios manipulativos (85 %), en sistemas lóticos (59 %) y con organismos heterótrofos (58 %). Los estresores más estudiados fueron los nutrientes (Nutr), la temperatura (Therm), la hidrología (Hydr), la radiación ultravioleta (UVR), los tóxicos (Toxic), la salinidad (Sal) y cambios en los usos del suelo. Los efectos individuales fueron más frecuentemente negativos (34 %) que positivos (26 %). Los efectos combinados no interactivos (50 %) e interactivos (50 %) tuvieron una frecuencia similar. Los antagonismos (18 %) fueron ligeramente más frecuentes que los sinergismos (15 %), efectos reversos u opuestos (13 %) y las interacciones de orden superior (4 %). Sin embargo, estas proporciones varían notablemente entre tipos de estudios, niveles de organización biológica y tipos de organismos. Nuestros resultados son útiles para predecir y gestionar los efectos de ciertas combinaciones de estresores en los ecosistemas acuáticos ibéricos. Las investigaciones futuras sobre estresores múltiples en el contexto Ibérico deberían: (i) intensificar el estudio de los sistemas lénticos, (ii) explorar más datos observacionales, (iii) organismos autótrofos y (iv) respuestas de la relación biodiversidad-funcionamiento del ecosistema y (v) cubrir un rango más amplio de factores estresantes y (vi) escenarios de estresores interactivos más complejos., We thank the Asociación Ibérica de Limnología for inviting us to contribute with this article and the editors and referees that kindly revised previous versions of this manuscript. CG-C was supported by a “Juan de la Cierva – Incorporación” contract from Ministerio de Ciencia e Innovación (MICINN, IJC2018-036642-I). RA-R held a pre-doctoral grant BES-2015-073961 (FPI) funded by Ministerio de Economía y Competitividad. DB was funded by “PTI ECOBIODIV” through the “Vicepresidencia Adjunta de Áreas Científico-Técnicas (VAACT-CSIC). MJC was support ed by Juan de la Cierva-Formación (FJCI-2017-32318) and Incorporación (IJC2019-040850-I) contracts from MICINN. JMG-O was funded by University of Granada through Programa de Promoción y Empleo joven from Junta de Andalucía and FEDER (PEJ2018-003106-A). FP was funded by “Consejería de Economía, Conocimiento, Empresas y Universidad de la Junta de Andalucía-Fondo Social Europeo de Andalucía 2014-2020”. DS-F was supported by a Ramón y Cajal contract (RYC2019-027446-I), and SP by a “Juan de la Cierva-Formación” postdoctoral contract MICINN, FJC2018-035577-I).

Accurate assessments of species' vulnerability to climate change require integrated measurements of its different drivers, including extrinsic (the magnitude and rate of climate change) and intrinsic factors (organisms' sensitivity and adaptive capacity). According to these factors, aquatic insects restricted to alpine ponds may be especially threatened by climate change. However, vulnerability predictions based on such an integrative approach are scarce for alpine pond taxa. We combined distributional, climatic data and experimental measurements of heat tolerance and acclimation capacity of two water beetles endemic to Sierra Nevada National Park (Spain) to evaluate different components of their vulnerability to climate change. We estimated: (i) changes in climatically suitable habitat under different scenarios of climate change and (ii) thermal safety margins (the difference between species upper thermal limits and the maximum temperatures in their current localities), for current and future conditions, and acclimation capacity, as measures of the physiological capacity to persist in situ. Species distribution models predicted a virtual loss of climatically suitable area under different climate change scenarios. Nonetheless, both taxa showed heat tolerance limits above the predicted maximum temperatures in their current localities (but no capacity to adjust such limits through acclimation). Therefore, these beetles could have the physiological capacity to deal with warming conditions in situ. We recommend concentrating conservation efforts in current localities as the most efficient management strategy for both taxa. Our results stress the importance of accounting for physiological tolerances when predicting the vulnerability to climate change in alpine freshwater biota.

Much recent scientific, media and public attention has focussed on the evidence for and consequences of declines in insect biodiversity. Reliable, complete inventories can be used to estimate insect trends accurately, but incomplete data may distort assessments of biodi-versity change. Thus, it is essential to understand the completeness of insect inventories. Assessing the database of Great Britain butterfly occurrences, likely the most complete database for any group of insects in the world (with 10,046,366 records for 58 butterfly species), we found that only 62% of the cells have complete inventories at the finest scale evaluated. The dynamic nature of butterfly distributions in response to climate change could explain this result, as the distribution of completeness values is related to the increas-ing occurrence of some species at higher latitudes as a consequence of recent range expan-sions. The exceptional quantity of information collected in Great Britain about this appeal-ing group of insects is insufficient to provide a complete picture. Consequently, we cannot expect to build complete inventories for less popular taxa, especially in less comprehen-sively sampled countries, and will require other techniques to understand the full extent of global biodiversity loss., D. S-F was supported by a postdoctoral grant from the University of Murcia (Spain).

1. Rivers are dynamic ecosystems in which both human impacts and climate-driven drying events are increasingly common. These anthropogenic and natural stressors interact to influence the biodiversity and functioning of river ecosystems. Disentangling ecological responses to these interacting stressors is necessary to guide management actions that support ecosystems adapting to global change. 2. We analysed the independent and interactive effects of human impacts and natural drying on aquatic invertebrate communities—a key biotic group used to assess the health of European freshwaters. We calculated biological response metrics representing communities from 406 rivers in eight European countries: taxonomic richness, functional richness and redundancy, and biomonitoring indices that indicate ecological status. We analysed metrics based on the whole community and on a group of taxa with traits promoting resistance and/or resilience (‘high RR’) to drying. We also examined how responses vary across Europe in relation to climatic aridity. 3. Most community metrics decreased independently in response to impacts and drying. A richness-independent biomonitoring index (the average score per taxon; ASPT) showed particular potential for use in biomonitoring, and should be considered alongside new metrics representing high RR diversity, to promote accurate assessment of ecological status. 4. High RR taxonomic richness responded only to impacts, not drying. However, these predictors explained little variance in richness and other high RR metrics, potentially due to low taxonomic richness. Metric responsiveness could thus be enhanced by developing region-specific high RR groups comprising sufficient taxa with sufficiently variable impact sensitivities to indicate ecological status. 5. Synthesis and applications. Metrics are needed to assess the ecological status of dynamic river ecosystems—including those that sometimes dry—and thus to identify priority sites requiring action to tackle the causes of environmental degradation. Our results inform recommendations guiding the development of such metrics. We propose concurrent use of richness-independent ‘average score per taxon’ indices and metrics that characterize the richness of resistant and resilient taxa. We observed interactions between aridity, impacts and drying, highlighting that these new metrics should be region specific, river type specific and adaptable, promoting their ability to inform management actions that protect biodiversity in river ecosystems responding to climate change. European Cooperation in Science and Technology. Grant Number: CA15113

1. The description of how biological information is compiled over time is essential to detect temporal biases in biodiversity data that could directly influence the utility, comparability, and reliability of ecological and biogeographical studies. 2. We explore trends in species recording over time using one of the most spatially and temporally comprehensive country-level databases for any group of insects in the world – the database of butterfly occurrences from Great Britain. 3. Firstly, we used two crucial milestones (the year in which the taxonomic inventory is complete, i.e., when the last species was recorded, the year in which all species are recorded together for the first time) to delimit threemain phases in the process of biodiversity recording (taxonomic, faunistic and exhaustive phases). Secondly, we aimed to quantify how far species features (attractiveness and detectability) influence the process of recording through time. 4. During the first stage of biodiversity compilation,when the main aim is to complete the taxonomic inventory (taxonomic period), entomologists tend to record attractive species more frequently. However, once the inventory is complete, particularly in the period during whichmore spatially and temporally comprehensive information about species distribution is amassed (the exhaustive period), the recording pattern clearly changes to more detectable species. 5. Common, highly detectable species are undersampled in the first phase of biodiversity data compilation and oversampled in the final stages. Awareness of such temporal patterns in recording is necessary in order to correctly interpret and address bias in insect biodiversity trends

The climatic variability hypothesis predicts the evolution of species with widethermal tolerance ranges in environments with variable temperatures, and theevolution of thermal specialists in thermally stable environments. In caves, theextent of spatial and temporal thermal variability experienced by taxadecreases with their degree of specialization to deep subterranean habitats. Weuse phylogenetic generalized least squares to model the relationship amongthermal tolerance (upper lethal limits), subterranean specialization (estimatedusing ecomorphological traits), and habitat temperature in 16 beetle species ofthe tribe Leptodirini (Leiodidae). We found a significant, negative relationshipbetween thermal tolerance and the degree of subterranean specialization. Con-versely, habitat temperature had only a marginal effect on lethal limits. Inagreement with the climatic variability hypothesis and under a climate changecontext, we show that the specialization process to live in deep subterraneanhabitats involves a reduction of upper lethal limits, but not an adjustment tohabitat temperature. Thermal variability seems to exert a higher evolutionarypressure than mean habitat temperature to configure the thermal niche of sub-terranean species. Our results provide novel insights on thermal physiology ofspecies with poor dispersal capabilities and on the evolutionary process ofadaptation to subterranean environments. We further emphasize that thepathways determining vulnerability of subterranean species to climate changegreatly depend on the degree of specialization to deep subterraneanenvironments., This work was supported by the Agencia Estatal de Investigación (Spain), the Spanish Ministry of Economy and Innovation and the European Regional Development Fund (project CGL2016-76995-P). RC is funded by a predoctoral grant of the Spanish Ministry of Science and Innovation (FPI). SP and DS-F are funded by postdoctoral contracts from the Spanish Ministry of Science and Innovation (Juan de la Cierva-Formación FJC2018-035577-I and Ramón y Cajal [RYC2019-027446-I] programs, respectively). SM acknowledges support from the European Commission through Horizon 2020 Marie Skłodowska-Curie Actions (MSCA) individual fellowships (Grant no. 882221).

This study investigated the effect of the main physicochemical factors in structuring aquatic macroinvertebrate assemblages of three streams in northern Tunisia. Aquatic macroinvertebrate and water physicochemical surveys were carried out seasonally in 2013, at three pristine sites and three altered sites located, respectively, in the upstream and downstream parts of the streams investigated. Macroinvertebrates were sampled using a kick net and a Surber net, and eight physicochemical factors were measured at the same time. Both biotic and abiotic data were analyzed using STATICO method. A total of 41 macroinvertebrate taxa were collected during the sampling period, and the most dominant taxa were Diptera (Culicidae) and Oligochaeta (Tubificidae). STATICO identified the dissolved oxygen, COD, and BOD5 as the major abiotic factors shaping macroinvertebrate assemblages. This study highlighted the impacts of anthropogenic land-based activities such as urban runoff on the distribution and diversity of macrobenthic invertebrates at the three downstream sites.

Since alien species may threaten native ecosystems when becoming invasive, one of the main challenges is try to predict their potential spread. Despite bees are essential pollinators and provide important ecosystem services in their native areas, outside these areas they could represent a risk for the local bee fauna, e.g. by competing for resources or by transmitting pathogens, as it was observed for species of Megachile, the bee genus with the highest number of recorded alien species. Here, using two complementary methods (Multidimensional Envelope procedure (MDE) and the Maximum Entropy algorithm (MaxEnt)), we aim to explore environmental niche as well as to identify potential worldwide distribution of the giant resin bee Megachile sculpturalis, native to Asia and recently introduced in North America and Europe. The two methodological approaches predict an important expansion for the species and reveal a preference for areas of Palearctic and Nearctic regions with reduced temperature fluctuations and moderate precipitation regimes. The Southern hemisphere seems not having good conditions for this species. Estimations for the future (2070) predict a further, though limited expansion to northern areas in the North hemisphere. However, during roughly 25 years of spreading outside its native range, M. sculpturalis clearly expanded the range of inhabitable environmental conditions, which may increase its potential invasiveness in a pattern difficult to predict using only correlative methods. Physiological and ecological data are necessary to better assess the potential niche of this bee species and in consequence to better predict its future spreading dynamics.

Accurate assessments of species vulnerability to climate change need to consider the physiological capacity of organisms to deal with temperature changes and identify early signs of thermally induced stress. Oxidative stress biomarkers and acetylcholinesterase activity are useful proxies of stress at the cellular and nervous system level. Such responses are especially relevant for poor dispersal organisms with limited capacity for behavioural thermoregulation, like deep subterranean species. We combined experimental measurements of upper lethal thermal limits, acclimation capacity and biomarkers of oxidative stress and neurotoxicity to assess the impact of heat stress (20°C) at different exposure times (2 and 7 days) on the Iberian endemic subterranean beetle Parvospeonomus canyellesi. Survival response (7 days of exposure) was similar to that reported for other subterranean specialist beetles (high survival up to 20°C but no above 23°C). However, a low physiological plasticity (i.e. incapacity to increase heat tolerance via acclimation) and signs of impairment at the cellular and nervous system level were observed after 7 days of exposure at 20°C. Such sublethal effects were identified by significant differences in total antioxidant capacity, glutathione S-transferase activity, the ratio of reduced to oxidized forms of glutathione and acetylcholinesterase activity between the control (cave temperature) and 20°C treatment. At 2 days of exposure, most biomarker values indicated some degree of oxidative stress in both the control and higherature treatment, likely reflecting an initial altered physiological status associated to factors other than temperature. Considering these integrated responses and the predicted increase in temperature in its unique locality, P. canyellesi would have a narrower thermal safety margin to face climate change than that obtained considering only survival experiments. Our results highlight the importance of exploring thermally sensitive processes at different levels of biological organization to obtain more accurate estimates of the species capacity to face climate change., This work was supported by the Agencia Estatal de Investigación (Spain), the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund [project CGL2016-76995-P]. S.P. is funded by a postdoctoral grant from Fundación Seneca - Agencia de Ciencia y Tecnología de la Región de Murcia (Spain), D.S-F is funded by a postdoctoral grant from the University of Murcia (Spain) and R.C. and P.B-G are funded by predoctoral grants from the Spanish Ministry of Science, Innovation and Universities

We thank two anonymous referees for valuable comments on the manuscript. DS‐F was supported by a postdoctoral contract funded by the Universidad de Castilla‐La Mancha and the European Social Fund (ESF), and PA is funded by ‘V Plan Propio de Investigacion’ of the Universidad de Sevilla (Spain).

One of the main challenges in ecology, biogeography and evolution is to understand and predict how species may respond to environmental changes. Here we focus on the deep subterranean environment, a system that minimizes most of the typical uncertainties of studies on epigean (surface) environments. Caves are relatively homogeneous habitats with nearly constant environmental conditions and simplified biological communities, allowing to control for biotic interactions. Thus, this particular system could be considered a natural habitat whose environmental conditions are similar to what can be reproduced in a laboratory, being an ideal model system for ecological, biogeographical and evolutionary studies. Subterranean species may potentially be used to assess the capability to persist in situ in a global change scenario, as they cannot accommodate to drastic changing conditions by behavioural plasticity, microhabitat use or by migrating to distant, more suitable areas, something frequent in epigean environments. In order to provide accurate predictions of the response of the subterranean biodiversity to climate change, we encourage evolutionary biologist, biogeographers and conservation biologist to work in this interesting ecosystem., DS-F was supported by a post-doctoral contract funded by Universidad de Castilla-La Mancha and the European Social Fund (ESF). This work was partly funded by two projects funded by the Spanish Ministry of Economy and Competitiveness (CGL2016-76995-P to DSF and CGL2016-76705-P to IR).

Recently, the European Commission adopted a new strategy to halt the loss of biodiversity. Member states are expected to favor a more effective collection and redistribution of European Union (EU) funds under the current Multiannual Financial Framework for 2014-2020. Because of the large spatial variation in the distribution of biodiversity and conservation needs at the continental scale, EU instruments should ensure that countries with higher biodiversity values get more funds and resources for the conservation than other countries. Using linear regressions, we assessed the association between conservation investments and biodiversity values across member states, accounting for a variety of conservation investment indicators, taxonomic groups (including groups of plants, vertebrates, and invertebrates), and indicators of biodiversity value. In general, we found clear overall associations between conservation investments and biodiversity variables. However, some countries received more or less investment than would be expected based on biodiversity values in those countries. We also found that the extensive use of birds as unique indicators of conservation effectiveness may lead to biased decisions. Our results can inform future decisions regarding funding allocation and thus improve distribution of EU conservation funds.

One of the most important issues in biodiversity conservation is an exploration of the relationships among protected areas, land-use changes and biodiversity, so we aimed to assess the performance of the Natura 2000 network (N2000) in representing the bat conservation hotspots in peninsular Spain and the Balearic Islands and to compare the rates of land-use changes within these hotspots with those observed throughout the rest of the study area. First, we applied a Combined Index that integrates various biodiversity metrics (species richness, rarity and vulnerability) to identify hotspots, and once they were identified, we used null models to assess the performance of N2000 in representing them. Finally, also using null models, we tested whether the changes in land use (“anthropization” or “naturalization”) within the hotspots occurred at a significantly higher or lower frequency than in the rest of the study area; for this, we considered two temporal windows (1980–2006 and 2006–2012) corresponding with periods before and after the official designation of the N2000 sites. Our results show that bat hotspots are effectively represented in the Iberian N2000, but although land-use changes were generally higher in Spain before 2006, hotspots have not experienced lower rates of change compared to the remainder of the territory (regardless of the period under consideration). This suggests low effectiveness of the Iberian N2000 in preventing land-use change in bat hotspots, so to preserve the Iberian bat fauna, we encourage the urgent implementation of management plans to avoid intensive changes in land use both inside and around bat hotspots.

Land-use intensification (LUI) and biological invasions are two of the most important global change pressures driving biodiversity loss. However, their combined impacts on biological communities have been seldom explored, which may result in misleading ecological assessments or mitigation actions. Based on an extensive field survey of 445 paired invaded and control plots of coastal vegetation in SW Spain, we explored the joint effects of LUI (agricultural and urban intensification) and invasion on the taxonomic and functional richness, mean plant height and leaf area of native plants. Our survey covered five invasive species with contrasting functional similarity and competitive ability in relation to the native community. We modeled the response of native communities for the overall and invader-specific datasets, and determined if invader-native functional differences could influence the combined impacts of LUI and invasion. Overall, we found that urban intensification reduced taxonomic richness more strongly at invaded plots (synergistic interactive effects). In contrast, functional richness loss caused by urban intensification was less pronounced at invaded plots (antagonistic interactive effects). Overall models showed also that urban intensification led to reduced mean leaf area, while agriculture was linked to higher mean plant height. When exploring invader-specific models, we observed that the combined effects of agricultural and urban intensification with invasion were heterogeneous. At invaded plots, invader-native functional differences accounted for part of this variability. Our findings demonstrate the importance of considering the interactive effects of global change pressures for a better assessment and management of ecosystems. Ministerio de Economía y Competitividad CGL2015-65346-R, FJCI-2015-25785, IJCI-2017-31733 Portuguese Foundation for Science and Technology UID/BIA/04050/2019, POCI-01-0145-FEDER-007569, CTA-AMB/31245/2017 Junta de Castilla-La Mancha POII10˗0179˗4700 Junta de Andalucía RNM-4031 Programa Severo Ochoa SEV-2012-0262

The need to use surrogates of biodiversity is quite relevant in threatened habitats harboring high values of biodiversity, such as the Mediterranean aquatic ecosystems. In this study, we assess the performance of eight macroinvertebrate groups (Coleoptera, Heteroptera, Odonata, Trichoptera, Plecoptera, Ephemeroptera, Crustacea, and Mollusca) as surrogates of the whole aquatic macroinvertebrate assemblage in 49 localities from Northern Africa (Tunisia). Specifically, we aimed to test i) the congruence of the patterns of species richness and composition among these eight groups (at species level) in order to propose which groups could be accurate as indicators of diversity of the whole community, and ii) if higher-taxon levels (genera or families) are suitable for predicting overall species richness and composition in these ecosystems. In total, we found 72 families, 157 genera and 280 species. Our results show a high congruence between the patterns of species richness and composition of Ephemeroptera, Coleoptera (even at higher taxonomic levels, especially genus) and the whole community. Thus, we recommend the use of these two groups as surrogates of macroinvertebrate diversity in inland aquatic ecosystem in the study area. They can be used for both i) the rapid and inexpensive monitoring of biodiversity in aquatic ecosystems and ii) conservational studies in order to identify areas with the highest values of freshwater biodiversity in Mediterranean areas. Finally, high values of congruence among taxonomic levels were found suggesting that, in general, higher taxa can be used as biodiversity surrogates for cost-effective practical survey in Mediterranean aquatic ecosystems from Northern Africa.

Cave-dwelling ectotherms, which have evolved for millions of years under stable thermal conditions, could be expected to have adjusted their physiological limits to the narrow range of temperatures they experience and be highly vulnerable to global warming. However, the few existing studies on thermal physiology in subterranean invertebrates point that they have lost some of the thermoregulatory mechanisms common in surface species, but there is a lack of evolutionary adjustment to ambient temperature. The question remains whether this surprising homogeneous thermal niche is common for the whole subterranean biodiversity or just a peculiarity of the species tested. In order to test for the generality of such previous findings, we studied basal heat tolerance and thermal plasticity in four species of distant arthropod groups (Coleoptera, Diplopoda and Collembola) with different evolutionary histories but under similar selection pressures, as they have been exposed to the same constant environmental conditions for a long time (inhabiting the same cave). Adult specimens were exposed at different temperatures for one week to determine upper lethal temperatures. Then, surviving individuals from each treatment were exposed to a fixed stressful temperature to determine acclimation capacity. Upper lethal temperatures were similar to those reported for other subterranean species (between 20-25°C), except from that of the diplopod (28°C), widely exceeding the cave temperature (13-14°C). Acclimation responses differed from a positive acclimation response in two of the species to no acclimation capacity or detrimental acclimation effects in the others. Our results show that thermal niche features are not as homogeneous as expected across the subterranean fauna and unrelated to ambient conditions. We show that some species, likely those that colonized subterranean environments more recently, still retain thermoregulation capacity to face temperature changes. Thus, subterranean species, even those living under similar climatic conditions, might be very differently affected by global warming.

Species of the genus Meladema (Dytiscidae, Colymbetinae) are some of the largest macroinvertebrates in the western Palearctic region, being top predators in fishless streams. Two of the three described species, Meladema imbricata (Wollaston, 1871) and Meladema lanio (Fabricius, 1775) are Macaronesian endemics from the Canary Islands and Madeira, respectively, while the third, Meladema coriacea Laporte, 1835, is widely distributed from Morocco and the Iberian Peninsula to Turkey, including the Canary Islands. Previous phylogenetic analysis using only mitochondrial markers revealed the existence of two cryptic lineages within M. coriacea, one restricted to Corsica and the other including the rest of sampled populations. We reconstruct here the evolutionary history of the species of Meladema using a more comprehensive sampling covering its whole geographical range, adding nuclear markers and Bayesian molecular dating. Using environmental niche modelling, we test for possible differences in climatic preferences among lineages and reconstruct their ancestral climatic niche. Our results strongly supported the existence of four monophyletic lineages represented by the three recognized species plus a fourth cryptic lineage with populations of M. coriacea from the Tyrrhenian islands (Corsica, Sardinia and Montecristo). This pattern is not likely to be the result of mitochondrial artefacts due to Wolbachia infection, as all 11 tested individuals were negative for this parasite. Dating analysis placed the origin of Meladema in the Middle Miocene although diversification among extant Meladema lineages started in the early Pleistocene and took place in a relatively short time period. Phylogeographic analysis inferred a continental origin of Meladema, with an independent colonization of the Macaronesian and Mediterranean islands. From the south-western Mediterranean region, the continental M. coriacea expanded its range up to Bulgaria and Turkey in the northern basin and to Tunisia in the southern. Results of niche modelling showed that seasonality is the critical factor in shaping the current distribution of Meladema. Island lineages (M. imbricata, M. lanio and the Tyrrhenian lineage of M. coriacea) occur in sites with low seasonality, within the range of the reconstructed ancestral climatic niche of the genus. On the contrary, continental M. coriacea expanded its range to localities outside the ancestral climatic range of the genus, with a higher seasonality and aridity.

International audience; The Permian-Triassic rifting represents the first of the two Mesozoic rifting stages recorded in the Iberian Peninsula. Its first phases of development started during the Early Permian, and were linked to the beginning of the break-up of Pangea, the large, unique and rheologically unstable supercontinent that mainly resulted from the collision of Gondwana and Laurussia. This chapter analyzes this first rifting stage in Iberia in two separate phases, an initial or tectonic phase, and a later mature phase. This analysis focuses on the main Permian-Triassic basins of the Iberian Peninsula: the Pyrenean, Iberian, Catalan, Ebro and Betic basins, as well as the basins located in the present-day Balearic Islands. In order to achieve a better understanding of the analyses of these basins, a multidisciplinary approach has been carried out by 48 researchers, including studies of tectonics, sedimentology, magmatism, mineralogy, geochemistry and paleontology.

The Iberian Peninsula is one of the European regions with the highest number of endemic species. Therefore, it is imperative to identify species populations potentially affected by variations in ecosystem functioning. Since the emergence of data processed from satellites, the possibility of carrying out studies covering both a spatial and temporal dimension has increased, providing more comprehensive information about species population dynamics and ecosystems. Primary productivity is a crucial parameter for understanding ecosystem function and services because it is the basis of the trophic chain. This study examines the spatiotemporal variation in primary productivity over a 14-year temporal series (2000–2013) through the enhanced vegetation index (EVI). We focused on the hotspots of endemic diurnal butterflies in the Iberian Peninsula and obtained data on the primary productivity dynamics at these locations as indicators to optimize further conservation efforts. Within these hotspots, statistically significant yet spatially irregular trends were found at localized sites, mostly in mountain systems (the Cantabrian Mountains, Iberian System, Sierra de Guadarrama and Sierra Nevada). At 60% of these sites, primary productivity significantly decreased. Two endemic species, the Sierra Nevada blue (Polyommatus golgus) and the Puerto del Lobo butterfly (Agriades zullichi), which are classified by the International Union for Nature Conservation (IUCN) as “Vulnerable” and “Endangered”, respectively, are present in localities where primary productivity showed a marked decline despite being within the Natura 2000 Network. The procedures developed here, which are based on consistent temporal trends of primary productivity, can serve as a tool to detect among biodiversity hotspots those locations where environmental change is unequivocal and hence further monitoring is needed., This study was supported by the projects NICHEAPPS (CGL2014-56416-P) granted to P.A., funded by the Spanish Ministry of Economy and Competitiveness (MINECO), and POII11-0277-5747, funded by the “Junta de Castilla-La Mancha”. P.A. was supported by the MINECO Ramón y Cajal Program (RYC-2011-07670). DS-F was supported by two post-doctoral contracts funded by the University of Castilla-La Mancha and the University of Murcia.

Considering how organisms adapt to stress is essential if we are to anticipate biological responses to global change in ecosystems. Communities in stressful environments can potentially be assembled by specialists (i.e. species that only occur in a limited range of environmental conditions) and/or generalist species with wider environmental tolerances. We review the existing literature on the salinity tolerance of aquatic insects previously identified as saline specialists because they were exclusively found in saline habitats, and explore if these saline realized niche specialists are also specialists in their fundamental niches or on the contrary are fundamental niche generalist species confined to the highest salinities they can tolerate. The results suggest that species inhabiting saline waters are generalists in their fundamental niches, with a predominant pattern of high survival in freshwater-low salinity conditions, where their fitness tends to be similar or even higher than in saline waters. Additionally, their performance in freshwater tends to be similar to related strictly freshwater species, so no apparent trade-off of generalization is shown. These results are discussed in the framework of the ecological and evolutionary processes driving community assembly across the osmotic stress gradient, and their potential implications for predicting impacts from saline dilution and freshwater salinization. This article is part of the theme issue ‘Salt in freshwaters: causes, ecological consequences and future prospects’.

One of the main challenges in disciplines such as ecology, biogeography, conservation and evolutionary biology is to understand and predict how species will respond to environmental changes, especially within a climate change context. We focus on the deep subterranean environment to minimize uncertainties in predictions, because it is one of the few ecosystems in nature whose environmental conditions are as homogeneous as those in the laboratory and their species cannot accommodate to changing conditions by behavioural plasticity, dispersal or microhabitat use (i.e., their only possibility to cope with climate change is to persist in situ). The hypotheses established for this project are based on the exciting results obtained in some of our previous studies, in which, we found that different subterranean beetle species living under different environmental conditions have identical/similar narrow thermal tolerance ranges, suggesting a lack of evolutionary adjustment to ambient temperature for these species. This could be due to the loss of some of the physiological mechanisms related to thermal tolerance, with a likely high metabolic cost, in a stable environment but with severe resource restrictions. However, the question that remains is to what extent this surprising narrow and homogeneous thermal niche is common for the whole subterranean biodiversity, and how this issue could determine the fate of subterranean biodiversity to climate change. In this project, we are testing for the generality of these exciting previous findings by studying the thermal niche (species acclimation abilities and thermal tolerances) of different lineages of cave beetles with different degrees of specialization to subterranean environments and from different geographical areas (Pyrenees and Cantabrian Mountains) (Suppl. material 1).

Thermal tolerance is a key vulnerability factor for species that cannot cope with changing conditions by behavioural adjustments or dispersal, such as subterranean species. Previous studies of thermal tolerance in cave beetles suggest that these species may have lost some of the thermoregulatory mechanisms common in temperate insects, and appear to have a very limited thermal acclimation ability. However, it might be expected that both thermal tolerance and acclimation ability should be related with the degree of specialization to deep subterranean environments, being more limited in highly specialized species. To test this hypothesis, we use an experimental approach to determine the acclimation capacity of cave beetles within the tribe Leptodirini (family Leiodidae) with different degrees of specialization to the deep subterranean environment. For this, we acclimate groups of individuals at a temperature close to their upper thermal limit (20ºC) or a control temperature (approximately that of the cave in which they were found) for 2 or 10 days (short- vs. long-term acclimation). a temperature close to their upper thermal limit (20ºC) or a control temperature (approximately that of the cave in which they were found) for 2 or 10 days (short- vs. long-term acclimation). Upper thermal limits (heat coma temperature, HC) are then measured for each individual using a ramping protocol (rate of increase of 1ºC/min) combined with infrared thermography and video recording. Preliminary results in a deep subterranean species (Speonomidius crotchi, with an intermediate degree of specialization) showed no significant effect of acclimation temperature in HC at any of the exposure times. Such reduced thermal plasticity could be also expected for other highly specialized subterranean species. The potential implications of these findings for subterranean biodiversity in a climate change context are discussed.

Biodiversity databases are typically incomplete and biased. We identify their three main limitations for characterizing the geographic distributions of species: unknown levels of survey effort, unknown absences of a species from a region, and unknown level of repeated occurrence of a species in different samples collected at the same location. These limitations hinder our ability to distinguish between the actual absence of a species at a given location and its (erroneous) apparent absence as consequence of inadequate surveys. Good practice in biodiversity research requires knowledge of the number, location and degree of completeness of relatively well-surveyed inventories within territorial units. We herein present KnowBR, an application designed to simultaneously estimate the completeness of species inventories across an unlimited number of spatial units and different geographical extents, resolutions and unit expanses from any biodiversity database. We use the number of database records gathered in a territorial unit as a surrogate of survey effort, assuming that such number correlates positively with the probability of recording a species within such area. Consequently, KnowBR uses a “record-by-species” matrix to estimate the relationship between the accumulated number of species and the number of database records to characterize the degree of completeness of the surveys. The final slope of the species accumulation curves and completeness percentages are used to discriminate and map well-surveyed territorial units according to user criteria. The capacity and possibilities of KnowBR are demonstrated through two examples derived from data of varying geographic extent and numbers of records. Further, we identify the main advances that would improve the current functionality of KnowBR., The development of KnowBR has been supported by the projects BIOWEB (CGL2011-15622-E BOS) and BANDENCO (POII11-0277-5747) founded by Spanish Ministerio de Ciencia e Innovación and the Consejería de Educación, Ciencia y Cultura-Junta de Comunidades de Castilla-La Mancha, respectively. DSF was supported by a post-doctoral contract funded by Universidad de Castilla-La Mancha and the European Social Fund (ESF).

Background Predicting the patterns of range expansion of alien species is central to develop effective strategies for managing potential biological invasions. Here, we present a study on the potential distribution of the American cavity-nesting, Orthoptera-hunting and solitary wasp, Isodontia mexicana (Hymenoptera: Sphecidae), which was first detected as alien species in France in 1960 and now is present in many European countries. After having updated its current distribution, we estimated the environmental space (based on bioclimatic data and altitude) occupied by the species and subsequently predicted its environmental potential distribution under both present and future climatic conditions at global scale. Results The wasp lives in low-altitude areas of the Northern hemisphere with moderate temperatures and precipitation. The environmental space occupied in the invaded area is practically just a subset (42%) of that occupied in the native area, showing a process of environmental niche unfilling (i.e. the species only partially fills its environmental niche in the invaded range). Besides, I. mexicana could also live in other temperate areas, mainly in the Southern hemisphere, particularly close to the coasts. However, geographic (oceans) and/or climatic (tropical areas, mountain chains) barriers would prevent the species to reach these potential areas unless through human trade activity. The species could thus only reach, by active dispersion, the remaining invadable areas of Europe. Estimations for the future (2050 and 2070) predict an expansion through active dispersion towards North in the native range and towards North and East in the invaded range, but future conditions would not break down the current climatic barriers in the Southern hemisphere. Conclusions Isodontia mexicana has not shifted its environmental niche in the invaded area. It could still occupy some new areas by active dispersion, but confined to Europe. The conspicuous niche unfilling shown by this wasp species could reflect the likely single introduction in Europe just a few decades ago. Furthermore, results stay in line with other studies that found niche unfilling rather than niche expansion in insects.

The Iberian Peninsula is a major European region of biodiversity, as it harbours more than 30% of European endemic species. Despite a number of studies having evaluated the ability of nature reserves to protect certain taxa, there is still a lack of knowledge on how Iberian endemic fauna are represented in these reserves. We detected biodiversity hotspots of Iberian endemicity and evaluated the effectiveness of the Natura 2000 network (N2000) in representing 249 endemic species from eight animal taxonomic groups (amphibians, mammals, freshwater fishes, reptiles, water beetles, butterflies, lacewings and dung beetles). We found that only the 10% of these Iberian endemic species are considered species of community interest (i.e. species included in the Annexes of the Habitats Directive). We conducted gap analyses and null models of representativeness in N2000. Generally, N2000 is effective in its representation of Iberian endemic fauna, although we detected species and few hotspots of endemism that were still not represented. It is necessary to declare a few new protected areas, thus enhancing N2000's effectiveness in the conservation of the Iberian endemic fauna. Although the aim of N2000 is to protect species listed in the Birds and Habitats Directives, the conservation status of endemic species from one of the most important areas of Europe in terms of biodiversity, could be also a concern for the European Union. Our results are useful in the context of the recent European Commission mandate calling for a ‘fitness check’ of the Birds and Habitats Directives. This approach could be also applicable to other regions with high value of endemicity., DS‐F was supported by a post‐doctoral contract funded by Universidad de Castilla‐La Mancha and the European Social Fund (ESF). PA was supported by a ‘Ramón y Cajal’ contract (RYC‐2011‐07670, MINECO). This research was partially funded by project POII11‐0277‐5747 (Junta de Castilla‐La Mancha).