124 research outputs found
Habitat use and implications for the conservation of a population of bottlenose dolphins, <i>Tursiops truncatus</i>, in the San Antonio Bay, Rio Negro Province, Argentina
Dermocystid infection and associated skin lesions in free-living palmate newts (Lissotriton helveticus) from Southern France
Since the early 1900s, mesomycetozoan parasites have been reported in both European anuran and caudate species. These reports have primarily been descriptive, which has made assessing the impact of these parasites on host populations difficult. Anecdotal reports of Dermocystidium-like parasites are becoming widespread across Europe, possibly indicating that these mesomycetozoan parasites are increasing in distribution and/or abundance. This highlights the need for further investigations into the occurrence, pathogenesis and effects on host health of these parasitic infections for free-living amphibian populations, particularly those which are already stressed or threatened by other factors. Here we report the results of pathological, microbiological and molecular investigations used to characterize unidentified skin lesions in palmate newts (Lissotriton helveticus) from Larzac, France. We confirm that the lesions are the result of infection with a novel dermocystidium-like parasite, which is related to Amphybiocystidium ranae. We also show that the same parasite is distributed across several newt breeding sites. The lesions that result from infection with this parasite range from single or few vesicular or nodular cutaneous lesions to multiple coalescing skin ulcers with extensive hemorrhages. The latter have not been previously described in amphibians due to mesomycetozoan parasitic infection. Dermocystid DNA was detected only in newts that showed lesions, providing comparative evidence of the parasite's pathogenicity. We discuss the potential significance of the presence of this pathogen in the context of the population health of palmate newts
The use of visual and automatized behavioral markers to assess methodologies: a study case on PIT-tagging in the Alpine newt
peer reviewedBiomarkers are now widely used as tools in various research fields to assess individual integrity. The recent advances in quantification methods of behavioral patterns, such as computerized video-tracking procedures, make them valuable biomarkers. However, the corollary of these novelties is that they remain relatively unknown and unused. In this study, we show that such tools can assess the validity of research methods, such as individual recognition. To demonstrate this we employed as a model a marking method (Passive Integrate Transponders: PIT-tagging) widely used in amphibians. Both detailed visual observations and video-tracking methods were complementary in highlighting components at different behavioral scales: locomotion, feeding, and breeding. We illustrate the scientific and ethical adequacy of the targeted marking method but also suggest that more studies should integrate behavioral analyses. Such biomarkers are a powerful tool to assess conservation concerns when other techniques cannot detect detrimental effects
The distributions of the six species constituting the smooth newt species complex (Lissotriton vulgaris sensu lato and L. montandoni) – an addition to the New Atlas of Amphibians and Reptiles of Europe
The ‘smooth newt’, the taxon traditionally referred to as Lissotriton vulgaris,
consists of multiple morphologically distinct taxa. Given the uncertainty concerning the
validity and rank of these taxa, L. vulgaris sensu lato has often been treated as a single,
polytypic species. A recent study, driven by genetic data, proposed to recognize five species,
L. graecus, L. kosswigi, L. lantzi, L. schmidtleri and a more restricted L. vulgaris. The
Carpathian newt L. montandoni was confirmed to be a closely related sister species. We
propose to refer to this collective of six Lissotriton species as the smooth newt or Lissotriton
vulgaris species complex. Guided by comprehensive genomic data from throughout the range
of the smooth newt species complex we 1) delineate the distribution ranges, 2) provide a
distribution database, and 3) produce distribution maps according to the format of the New
Atlas of Amphibians and Reptiles of Europe, for the six constituent species. This allows us to
4) highlight regions where more research is needed to determine the position of contact zones
Assessment of habitat and survey criteria for the great crested newt (Triturus cristatus) in Scotland: a case study on a translocated population
The great crested newt Triturus cristatus has declined across its range due to habitat loss, motivating research into biotic and abiotic species determinants. However, research has focused on populations in England and mainland Europe. We examined habitat and survey criteria for great crested newts in Scotland, with focus on a large, translocated population. Adult counts throughout the breeding season were obtained annually using torchlight surveys, and Habitat Suitability Index (HSI) assessed at created ponds (N = 24) in 2006 (immediately post-translocation) and 2015 (9 years post-translocation). In 2006, ‘best case’ HSI scores were calculated to predict habitat suitability should great crested newts have unrestricted access to terrestrial habitat. Abiotic criteria included in and omitted from current great crested newt survey guidelines were assessed using data recorded in 2015. Some ponds had improved HSI scores in 2015, but overall failure to meet predicted scores suggests management is needed to improve habitat suitability. Great crested newt activity was positively associated with moon visibility and phase, air temperature, and pH, but negatively correlated with water clarity. Importantly, our results indicate there are abiotic determinants specific to Scottish great crested newts. Principally, survey temperature thresholds should be lowered to enable accurate census of Scottish populations
Contrasting effects of nitrogenous pollution on fitness and swimming performance of Iberian waterfrog, Pelophylax perezi (Seoane, 1885), larvae in mesocosms and field enclosures
A co-development approach to conservation leads to informed habitat design and rapid establishment of amphibian communities
1. Effective wildlife restoration is a critical requirement of many conservation actions. The outcome of conservation interventions can be optimised through knowledge of species’ habitat requirements, but few studies consider the impact of using explicit evidence from dedicated local research to inform the design phase of habitat management. Furthermore, interventions administered externally from the top down, whilst simpler than those developed in discussion with multiple stakeholders including land managers (i.e. co-development), run the risk of failing to engage local people.
2. In this study, we focus on interventions in the Scottish Highlands to improve the availability and suitability of breeding ponds for local amphibian assemblages. We collected and analysed data based on 129 ecological variables across 88 reference ponds to quantify the local habitat preferences. We used the findings from these analyses to inform the construction or restoration of 25 intervention ponds co-developed in partnership with stakeholders (landowners, foresters, citizen scientists and government agencies). Following the interventions, we monitored amphibian communities at these sites over 4 years. We assessed presence and abundance of all five native amphibians (the anurans Rana temporaria and Bufo bufo, and the salamanders Lissotriton helveticus, L. vulgaris and Triturus cristatus) using egg searching, dip-netting, torching and trapping.
3. The new habitats were overall characterised by ecological conditions more favourable to amphibians than the reference ponds. We recorded a total of 51 colonisation events. Within two breeding seasons after construction or restoration, the intervention ponds hosted the full complement of species, mirroring amphibian diversity patterns found in the local reference ponds.
4. Our study shows that ecological research to quantify local habitat requirements and working with commercial land-managers to ensure equitable benefits prior to designing conservation actions can promote rapid and efficient recovery of wildlife
Recovery of high mountain Alpine lakes after the eradication of introduced brook trout Salvelinus fontinalis using non-chemical methods
The final publication is available at Springer via http://dx.doi.org/10.1007/s10530-018-1867-0Fish stocking is a serious threat to originally fishless mountain lakes. We used non-chemical eradication methods (i.e. gillnetting and electrofishing) in four high mountain lakes in the Gran Paradiso National Park (Western Italian Alps) to eradicate alien brook trout Salvelinus fontinalis. Data of amphibians, macroinvertebrates, zooplankton, chlorophyll-a, nutrient concentrations, and water transparency were used as indicators of the recovery process. All treated lakes were returned to their original fishless condition in spite of their different sizes and habitat complexity, without permanent negative side-effects for native species. Several ecological indicators showed that many impacts of introduced fish can be reversed over a short time period following eradication. The present study adds to a still growing body of specialized literature on the recovery of habitats after the eradication of alien species and provides further evidence that physical eradication methods are effective and can be part of a more general strategy for the conservation of high mountain lake biota
The influence of insecticide exposure and environmental stimuli on the movement behaviour and dispersal of a freshwater isopod
Why Should We Preserve Fishless High Mountain Lakes?
High mountain lakes are originally fishless, although many have had introductions of non-native fish species, predominantly trout, and recently also minnows introduced by fishermen that use them as live bait. The extent of these introductions is general and substantial often involving many lakes over mountain ranges. Predation on native fauna by introduced fish involves profound ecological changes since fish occupy a higher trophic level that was previously inexistent. Fish predation produces a drastic reduction or elimination of autochthonous animal groups, such as amphibians and large macroinvertebrates in the littoral, and crustaceans in the plankton. These strong effects raise concerns for the conservation of high mountain lakes. In terms of individual species, those adapted to live in larger lakes have suffered a higher decrease in the size of their metapopulation. This ecological problem is discussed from a European perspective providing examples from two study areas: the Pyrenees and the Western Italian Alps. Species-specific studies are urgently needed to evaluate the conservation status of the more impacted species, together with conservation measures at continental and regional scales, through regulation, and at local scale, through restoration actions, aimed to stop further invasive species expansions and to restore the present situation. At different high mountain areas of the world, there have been restoration projects aiming to return lakes to their native fish-free status. In these areas autochthonous species that disappeared with the introduction of fish are progressively recovering their initial distribution when nearby fish-free lakes and ponds are available
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