AIM: Mountain regions are particularly well‐suited for investigating the impact of climate change on species ranges because they encompass both upper and lower limits of species distribution. Here, ...we investigate changes in the elevational distribution of dung beetle species (Coleoptera: Scarabaeoidea) in two separate mountain regions in Europe. LOCATION: South‐western Alps (France) and Sierra Nevada (Spain). METHODS: We compared historical and current data on dung beetle distributions along elevation gradients for 30 species in the SW Alps and 19 species in the Sierra Nevada. We tested for significant changes between survey periods in three parameters: mean elevation and upper and lower range limits. RESULTS: We found up‐slope range shifts for 63% and 90% of the species in the SW Alps and Sierra Nevada, respectively. Up‐slope range shifts resulted mainly from expansion of upper range limits in the SW Alps and from changes of both range limits in the Sierra Nevada. The magnitudes of range shifts were consistent with the level of warming experienced in each region, but they also reflected the asymmetrical warming observed along the elevation gradients. Smaller changes were observed for species reaching their historical range limits at the higher elevations, associated with a non‐significant increase in temperature between periods. MAIN CONCLUSIONS: The differences observed between regions are related to the geographical position of each mountain range, which determines the characteristics (including thermal tolerance) of the regional species pool, and the level of warming, which determines whether maximum thermal tolerance has been exceeded for the majority of species in the region. Our results highlight the importance of considering both the biogeography of the mountain and the species pool under study when assessing the sensitivity of species to future climate change in mountain regions.
Trace elements can be toxic when they cannot be easily removed after entering an ecosystem, so a long-term assessment is fundamental to guide ecosystem restoration after catastrophic pollution. In ...1998, a pyrite mining accident in Aznalcóllar (south-western Spain) spilled toxic waste over a large area of the Guadiamar river basin, where, after restoration tasks, the Guadiamar Green Corridor was established. Eight years after the mine accident (2005–2006), the ground-dwelling insectivorous lizard Psammodromus algirus registered high trace-element levels within the study area compared to specimens from a nearby unpolluted control site. In 2017, 20 years after the accident, we repeated the sampling for this lizard species and also quantified trace elements in vegetation as well as in arthropod samples in order to identify remnant trace-element accumulation with the aim of assessing the transfer of these elements through the trophic web. We found remnant trace-element contamination in organisms of the polluted site compared to those from the unpolluted site. All trace-element concentrations were higher in arthropods than in plants, suggesting these compounds bioaccumulate through the trophic web. Lizards from the polluted areas had higher As, Cd, and Hg concentrations than did individuals from the unpolluted area. Lizard abundance between sampling periods (2005–06 and 2017) did not vary in unpolluted transects but strongly declined at polluted ones. By contrast, the Normalized Difference Vegetation Index indicated that in the study period, the vegetation was similar at the two sampling sites. These results suggest that, 20 years after the accident, the trace-element pollution could be the cause of a severe demographic decline of the lizard in the polluted area.
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•Trace elements in three trophic levels were assessed 20 years after a mine spill.•There was an apparent transfer of trace elements from plants to arthropods.•Lizards registered high trace element accumulation for As, Hg, and Cd.•Lizard density strongly declined at the polluted site with respect to the control one.•20 years after the spill, the trace element pollution persists in the Guadiamar basin.
20 years after the mine spill at the Guadiamar basin (southern Spain), plant, arthropod and lizard samples showed high concentration of trace elements, suggesting that the pollution persists.
•We perform long-term analysis of non-breeding counts of black-tailed godwits in Doñana.•Increasing numbers in winter was observed, but not changes in spring migration.•Increase in man-made ...artificial wetlands were associated to increasing godwits numbers.•Man-made habitats need to be considered in conservation plans for the species.
Over the last decades the Continental European population of black-tailed godwits, Limosa limosa limosa, has shown steep declines as a consequence of agricultural intensification on the breeding grounds. Although numbers have also declined in their traditional wintering areas in West-Africa, in the Doñana wetlands of southwestern Spain high nonbreeding numbers have persisted. Here we provide a long-term (35year, 1977–2011) analysis of godwit numbers in Doñana. In fact, from the mid 1990s there has been a steep increase in numbers so that the fraction of godwits along this flyway that winters in Doñana increased from 4% in the late 1980s to 23% in 2011. These changes were not correlated with climatic conditions in Spain, nor in Sahel, but they were associated with changes in habitat availability – mainly an increase in man-made artificial wetlands. Commercial fish-farms and rice fields provide alternative habitats to the original seasonal marshlands for daytime roosting (mainly in the fish ponds) or nocturnal foraging (probably rice fields in addition to fish ponds). For migrating waterbirds, degradations of natural wetlands can thus be compensated by man-made alternative habitats. As the availability especially of such man-made areas is highly sensitive to short-term political/economic driven decision-making, they should be given greater consideration in global conservation plans.
Migrating long distances requires time and energy, and may interact with an individual's performance during breeding. These seasonal interactions in migratory animals are best described in ...populations with disjunct nonbreeding distributions. The black‐tailed godwit (Limosa limosa limosa), which breeds in agricultural grasslands in Western Europe, has such a disjunct nonbreeding distribution: The majority spend the nonbreeding season in West Africa, while a growing number winters north of the Sahara on the Iberian Peninsula. To test whether crossing the Sahara has an effect on breeding season phenology and reproductive parameters, we examined differences in the timing of arrival, breeding habitat quality, lay date, egg volume, and daily nest survival among godwits (154 females and 157 males), individually marked in a breeding area in the Netherlands for which wintering destination was known on the basis of resightings. We also examined whether individual repeatability in arrival date differed between birds wintering north or south of the Sahara. Contrary to expectation, godwits wintering south of the Sahara arrived two days earlier and initiated their clutch six days earlier than godwits wintering north of the Sahara. Arrival date was equally repeatable for both groups, and egg volume larger in birds wintering north of the Sahara. Despite these differences, we found no association between wintering location and the quality of breeding habitat or nest survival. This suggests that the crossing of an important ecological barrier and doubling of the migration distance, twice a year, do not have clear negative reproductive consequences for some long‐distance migrants.
In this manuscript, we show that individuals of a long‐distance migrating shorebird (the black‐tailed godwit Limosa limosa) which spend their nonbreeding period in West Africa arrived and laid earlier than godwits migrating to wintering locations north of the Sahara, mainly in Doñana Wetlands, Spain. This contrasts with previously studied migrating bird species where migration distance tends to be positively correlated with arrival and/or laying date. In spite of their late arrival and laying, godwits which wintered closer to their Dutch breeding grounds laid larger eggs. We could, however, not find a correlation with other reproductive parameters.
Abstract
Editor's suggested further reading in BioEssays:
Evolution in response to climate change: In pursuit of the missing evidence
Abstract
How will fish that evolved at constant sub‐zero ...temperatures cope with global warming? Notothenioids as a case study
Abstract
Editor's suggested further reading in BioEssays: Evolution in response to climate change: In pursuit of the missing evidence
How will fish that evolved at constant sub‐zero temperatures cope with ...global warming? Notothenioids as a case study
The symposium “Global change in the Mediterranean: learning from experiences worldwide” held on 15–16 November 2012 in Seville, was funded by the EU's FP7 within the project ECOGENES. The contributions highlighted the need to incorporate environmentally‐induced variations in organismal development and ecological interactions into the global change research program.
Quantification of heavy metal concentrations in biota is a common technique that helps environmental managers measure the level of pollutants circulating in ecosystems. Despite interest in heavy ...metals as indicators of localized pollution, few studies have assessed these pollutants in reptiles. In 1998, the tailing pond of a pyrite mine near Aznalcóllar (southwestern Spain), containing mud with high heavy metal concentrations, collapsed, releasing 6 million m³ of toxic sludge into the Guadiamar Basin. Here we analyze heavy metal concentrations in the most common reptile in the area, the large psammodromus, Psammodromus algirus, a rather small lizard. We quantified levels of several elements (Hg, Sb, Cd, Cr, Tl, Sn, Ba, Cu, Pb, Sr, Mn, Rb, As, and Zn) in lizard tail clips collected in and around the affected area during the springs of 2005 and 2006. Samples were collected from two contaminated localities, one directly affected by the spill, and another adjacent to the tailing pond, but not covered by toxic mud. We also collected samples from a nonpolluted control site in the same basin. We found higher concentrations of As, Tl, Sn, Pb, Cd, and Cu in lizards from the affected area than in lizards from the control site, indicating the continued presence of heavy metal pollutants in the terrestrial food chain 8 years after the mine accident. We did not uncover sexual or annual differences in heavy metal concentrations, although concentrations increased with lizard size. We discuss how heavy metals moved across the food chain to lizards, despite intensive restoration efforts after the accident, and suggest that reptiles to be included in biomonitoring programs of heavy metals pollution in terrestrial habitats.
In Mediterranean areas, river systems are key for maintaining regional biodiversity by providing a high diversity of habitats. We studied bird community recovery for 9 years (2001–2009) during ...landscape restoration and Guadiamar Green Corridor establishment in the area affected by the Aznalcóllar mine spill (SW Spain, 1998). One year following plant restoration (3 years after the spill), values for α‐ and β‐bird species diversity were high, sooner than reported for similar restoration processes elsewhere. Species richness, ecological diversity, and abundance increased only slightly in the following 8 years. Overlap between communities in sequential years, measured by similarity indexes, increased throughout the study period to about 70% during final survey years, and most breeding bird species present before the accident again inhabit the area. Only 5 years after the mine accident, bird communities in the restored site were similar in species richness, abundance, and diversity to an unaffected reference site; redundancy analysis demonstrated that bird communities were also similar between the reference river and the Guadiamar. Despite the severity of the mine accident, our results suggest a swift recovery of the bird community. We attribute this success to the rapid restoration of habitat availability and the resilience of the birds. This long‐term study contributes to our limited knowledge of bird species response to habitat restoration following toxic spills in Mediterranean habitats.
Ecosystem restoration requires that habitat requirements of all species be considered. Among animal communities in Mediterranean ecosystems, reptiles, as ectothermic vertebrates, need refuges for ...avoidance of extreme environmental temperatures, concealment from predators, and oviposition sites. In 1998, a massive amount of tailings broke out of the holding pond of the Aznalcóllar mine (southwestern Spain) and polluted the Guadiamar river valley. After the accident, a soil- and vegetation restoration program began, and the Guadiamar Green Corridor was created to connect two huge natural areas, Doñana National Park and the Sierra Morena. Within this corridor, the reptile community remained dramatically impoverished, probably because of elimination of all natural refuges during the soil restoration program. To test this hypothesis, we set an array of artificial refuges (logs) in a large experimental plot. During the 5 years of the experiment (2002-2006), the area managed with artificial refuges exhibited a better and faster recovery of the reptile community in species richness and individual abundance than did the control area with no artificial refuges. Moreover, reptile colonization of the Guadiamar Green Corridor was transverse rather than lineal--that is, it did not act as a corridor for reptiles, at least in the first stages of colonization. This suggests that landscape restoration programs should not neglect refuge availability, a limiting resource for reptile species.
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