Protected areas (PAs) are pivotal tools for biodiversity conservation on the Earth. Europe has had an extensive protection system since Natura 2000 areas were created in parallel with traditional ...parks and reserves. However, the extent to which this system covers not only taxonomic diversity but also other biodiversity facets, such as evolutionary history and functional diversity, has never been evaluated. Using high-resolution distribution data of all European tetrapods together with dated molecular phylogenies and detailed trait information, we first tested whether the existing European protection system effectively covers all species and in particular, those with the highest evolutionary or functional distinctiveness. We then tested the ability of PAs to protect the entire tetrapod phylogenetic and functional trees of life by mapping species' target achievements along the internal branches of these two trees. We found that the current system is adequately representative in terms of the evolutionary history of amphibians while it fails for the rest. However, the most functionally distinct species were better represented than they would be under random conservation efforts. These results imply better protection of the tetrapod functional tree of life, which could help to ensure long-term functioning of the ecosystem, potentially at the expense of conserving evolutionary history.
Semiaquatic organisms depend on the features of both water bodies and landscapes; the interplay between terrestrial and aquatic systems might influence the semiaquatic communities, determining the ...scale at which management would be more effective. However, the consequences of such interplay are not frequently quantified, particularly at the community level. We analyzed the distribution of amphibians to evaluate whether the influence of landscape features on freshwater ecosystems can have indirect consequences at both the species and community level. We surveyed 74 streams in northern Italy to obtain data on breeding amphibians, water, and microhabitat features; we also measured features of surrounding landscapes. We used an information-theoretic approach and structural equation models to compare hypotheses on causal relationships between species distribution and variables measured at multiple levels. We also used a constrained redundancy analyses to evaluate causal relationships between multivariate descriptors of habitat features and community composition. Distribution of
Salamandra salamandra
was related to landscape, hydrological, and water characteristics: salamanders were more frequent in permanent streams with low phosphate concentration within natural landscapes. Water characteristics were dependent on landscape: streams in natural landscapes had less phosphates. Landscape influenced the salamander both directly and indirectly through its influence on phosphates. Community structure was determined by both landscape and water characteristics. Several species were associated with natural landscapes, and with particular water characteristics. Landscape explained a significant proportion of variability of water characteristics; therefore it probably had indirect effects on community. Upland environments play key roles for amphibians, for example, as the habitat of adults, but upland environments also have indirect effects on the aquatic life stages, mediated through their influence on water characteristics. Synergistic effects can magnify the negative consequences of landscape alteration on amphibians; landscape management can be particularly effective, as it can also improve wetland features.
Facultative paedomorphosis, a process in which newt larvae can opt for reproduction before or after metamorphosis, is geographically heterogeneous. Despite numerous ecological studies and recent ...evidence of declines in paedomorphic populations, however, no attempt to model environmental variables that explain the presence of paedomorphs has been made at a multi-scale level. Our aim was to fill this gap in studying three newt species (
Lissotriton vulgaris,
Mesotriton alpestris, and
Triturus macedonicus) of the Montenegrin karst as model species. To this end, we used multivariate analysis on three scales of habitat: the breeding pond, the land use and the climatologic features. Results show that the study area is both an important hotspot for paedomorphosis and where intraspecific diversity is quickly disappearing (20–47% extirpation) because of fish introductions. Other habitat variables (water permanency, pH or the habitat origin) were shown to act on paedomorphosis but not consistently across species, confirming complexity of the evolutionary and ecological processes. This study appeals for more long-term and detailed landscape studies of polyphenisms, a neglected but promising topic, to better understand and protect alternative modes of development. Particularly, measures should be taken to identify hotspots of intraspecific diversity at a global scale and stop fish introductions before we reach a point of no-return.
The use of lake sedimentary DNA to track the long-term changes in both terrestrial and aquatic biota is a rapidly advancing field in paleoecological research. Although largely applied nowadays, ...knowledge gaps remain in this field and there is therefore still research to be conducted to ensure the reliability of the sedimentary DNA signal. Building on the most recent literature and seven original case studies, we synthesize the state-of-the-art analytical procedures for effective sampling, extraction, amplification, quantification and/or generation of DNA inventories from sedimentary ancient DNA (sedaDNA) via high-throughput sequencing technologies. We provide recommendations based on current knowledge and best practises.
Despite early reports of its presence, no recent data exist on the distribution of the American bullfrog in Europe, the causes of introduction, or the trends of populations. We monitored the European ...situation at two spatial scales. In SW France, we performed call surveys over 2,500 wetlands. We found bullfrogs over about 2,000 km², apparently the European area in which the strongest expansion of bullfrogs is taking place. In addition, we used questionnaires to investigate the situation at the continental scale. At least 25 independent introductions occurred in Europe; eradication attempts were successful three times, and bullfrog populations are present in five countries. Education programs and monitoring are necessary to reduce the rate of introduction and to start management action as soon as possible.
Relocation of endangered species can be an effective conservation tool if it does not mix populations that represent significant intraspecific variation. The threatened Italian agile frog, Rana ...latastei, has small populations with low genetic diversity: translocation has been proposed to improve the likelihood of survival of populations. Using a common environment experiment and field surveys, we investigated whether there were differences in larval growth and developmental rate between foothill and lowland R. latastei populations, to evaluate if they are evolutionarily significant units. In nature, the colder climate of the foothills causes delayed metamorphosis. Conversely, in a common environment, larvae from foothill populations show faster growth and development. We did not find a significant egg-size related maternal effect or any differences in size at metamorphosis. We hypothesise that counter-gradient selection promoted fast growing phenotypes in a cold environment, where low temperatures slow down larval development. Foothill populations, despite being only a small geographical distance away from lowland populations, seem to be adapted to a colder climate and represent an evolutionarily significant unit. Different populations should, therefore, be managed independently, avoiding translocation. We suggest that evolutionary divergence between populations should be verified prior to planning relocation programmes, to prevent the risk of genetic homogenisation.
Populations of widely distributed species can be subjected to unequal selection pressures, producing differences in rates of local adaptation. We report a laboratory experiment testing tolerance ...variation to UV-B and polycyclic aromatic hydrocarbons (PAHs) among common frog (
Rana temporaria) populations according to their natural exposure level in the field. Studied populations were naturally distributed along two gradients, i.e. UV-B radiation with altitude and level of contamination by PAHs with the distance to emitting sources (road traffic). Tadpoles from eight populations were subjected to (1) no or high level of artificial UV-B; (2) four concentrations of benzoapyrene (BaP) (0, 50, 250, 500
μg
L
−1); (3) simultaneously to UV-B and BaP. Since both stressors are genotoxic, the number of micronucleated erythrocytes (MNE) in circulating red blood cells was used as a bioindicator of tadpole sensitivity. High-altitude populations appear to be locally adapted to better resist UV-B genotoxicity, as they showed the lowest MNE numbers. Conversely, no correlation was observed between levels of PAH contamination in the field and tadpole tolerance to BaP in the laboratory, indicating the absence of local adaptation for BaP tolerance in these populations. Nevertheless, the decrease of MNE formation due to BaP exposure with altitude suggests that high-altitude populations were intrinsically more resistant to BaP genotoxicity. We propose the hypothesis of a co-tolerance between UV-B and BaP in high-altitude common frog populations: local adaptation to prevent and/or repair DNA damage induced by UV-B could also protect these highland populations against DNA damage induced by BaP. The results of this study highlight the role of local adaptation along pollutant gradients leading to tolerance variation, which implies that is it necessary to take into account the history of exposure of each population and the existence of co-tolerance that can hide toxic effects of a new pollutant.
Development rate early in the ontogeny is believed to correlate positively with fitness. Geographic variation in intrinsic development rate suggests the existence of trade-offs between development ...rate and other fitness related traits. We investigated whether these trade-offs exist between intrinsic larval development rate and post-metamorphic traits in an organism with a complex life cycle. In laboratory, we measured if the tadpoles of the frog Rana latastei with fast intrinsic development rate have a suboptimal post-metamorphic morphology, by comparing froglets from five populations. Then, we evaluated the relationship between age at metamorphosis, hindlimb length and jumping performance for frogs grown in nature in two populations. Under laboratory conditions, froglets with fast intrinsic development had shorter absolute and shorter size-adjusted tibiofibulas. We observed a strong, positive relationship between tibiofibula length and jumping performance. In nature, froglets from the last metamorphosing population had longer absolute and size-adjusted tibiofibulas, and were able to jump further. The cost of fast development could be the shorter legs of early metamorphosing frogs, and their poor jumping performance. Thus, a fast intrinsic development rate may not always be positively related to lifetime fitness, since delayed effects of larval development persist also across life history stages.PUBLICATION ABSTRACT
Aim: General patterns of biodiversity, such as latitudinal gradients and species-area relationships, are found consistently in a wide range of organisms, but recent results for protist diversity ...suggest that organisms shorter than 2 mm do not display such patterns. We tested this prediction in bdelloid rotifers, pluricellular metazoans smaller than 2 mm, but with size and ecology comparable to protists. Location: A single valley in northern Italy was surveyed in detail and compared to all available faunistic data on bdelloids worldwide. Methods: We analysed 171 local assemblages of bdelloid rotifers living in 5 systems of dry mosses and submerged mosses in running water and in lakes. We compared patterns of alpha, beta, and gamma diversity, and nestedness of metacommunities, with those known from protists and larger organisms. Results: Bdelloid rotifers showed low local species richness (alpha diversity), with strong habitat selection, as observed in larger organisms. The number of species differed among systems, with a higher number of species in dry than in aquatic mosses. There was no hierarchical structure or exclusion of species in the metacommunity pattern within each system. Local diversity for the entire valley was surprisingly high compared with worldwide bdelloid diversity, similar to observed patterns in protists. Main Conclusions: Bdelloid rotifers have some of the peculiarities of protist biodiversity, although at slightly different spatial scales, thus confirming the idea of a major change in biodiversity patterns among organisms shorter than 2 mm. However, bdelloids show stronger habitat selection than protists. We suggest two possible explanations for the observed patterns: (1) dispersal is very rare, and not all bdelloid clones are arriving everywhere; and (2) dispersal is effective in displacing propagules, but environmental heterogeneity is very high and prevents many species from colonizing a given patch of moss.
PDF
