We investigated the ecological requirements in the emergence phase of two congeneric species of Aeshnidae, Aeshna grandis (Linnaeus 1758) and A. juncea (Linnaeus 1758), occurring in syntopy at the southernmost limit of their range. We sampled the exuviae of the two species at the peak of their emergence in three lakes in NW Italy. In each lake we defined 30 to 50 sampling plots along the lake borders where we checked for the presence of exuviae and collected data on the microhabitat composition. By modeling the response of the exuviae presence and abundance against the environmental parameters, we could highlight a partial differentiation in the ecological requirements of the two species at emergence. In particular, A. grandis is more influenced by the structure of the aquatic vegetation than A. juncea and the niche space occupied by A. grandis is wider, almost totally encompassing the one of A. juncea. We argue that A. grandis exploits microhabitats rich in aquatic plants to avoid competition with A. juncea. We suggest the preservation of well-structured aquatic vegetation as a key management practice to preserve the three studied populations of A. grandis, a species which has been recognized as Vulnerable for Italy according to the IUCN criteria.
Salinity is a limiting factor for many invertebrates, especially for Odonata which are typically associated with freshwater ecosystems. In Europe, 15 Odonata species inhabit brackish wetlands and only few detailed data on their tolerance towards salinity are available. We investigated Odonata fauna in 11 sampling stations situated in three estuarine areas (northern Adriatic coastline) which differed in salinity conditions (freshwater- polyhaline habitats) in order to assess affinity of Odonata species to brackish habitats and to describe their distribution pattern in coastal wetlands. Adults, exuviae (the remains of the exoskeleton after the last larval instar), and the main chemical and physical water parameters were sampled every 2 weeks for 1 year in each station. In total, 25 species were detected and 56% of them were able to complete their life cycle in brackish water environments. Our results showed that freshwater and oligohaline ponds were the most favorable for dragonflies, with an overall higher species richness. There was a high species turnover along the salinity gradient, with a strong differentiation among the communities along the gradient. Considering the exuviae, we observed a high specificity with respect to the habitat conditions (seven species exclusive of freshwater sites and six of oligohaline ones, respectively). Among the adults, four species were found exclusively in freshwater habitats and no species seemed to be strictly connected with oligohaline habitats. Coastal wetlands are composed by a mosaic of different habitats especially when freshwater and seawater are close together, supporting many Odonata species with different tolerance toward salinity conditions. They also provide useful insights for conservation and management actions.
The Vagrant Emperor, Anax ephippiger (burmeister, 1839), is a migrant dragonfly species from africa and Middle East; in Europe only summer generation are known, without evidence of overwintering larvae. In august 2010 a reproductive breeding site for this species was found in the in Friuli-Venezia Giulia Region (north-eastern Italy). This discovery represents the first proof of reproduction for the species in north-eastern Italy. With the aim of increasing the knowledge on the species requirements, a study to delineate the emerging habitat was conducted: dragonfly community (adult and exuviae), vegetation, chemical and physical water parameters were sampled. This yielded data about larval tolerance toward salinity. This new data proves a northward move for the species, which may also have been facilitated by global warming.
Effective and targeted conservation action requires detailed information about species, their distribution, systematics and ecology as well as the distribution of threat processes which affect them. Knowledge of reptilian diversity remains surprisingly disparate, and innovative means of gaining rapid insight into the status of reptiles are needed in order to highlight urgent conservation cases and inform environmental policy with appropriate biodiversity information in a timely manner. We present the first ever global analysis of extinction risk in reptiles, based on a random representative sample of 1500 species (16% of all currently known species). To our knowledge, our results provide the first analysis of the global conservation status and distribution patterns of reptiles and the threats affecting them, highlighting conservation priorities and knowledge gaps which need to be addressed urgently to ensure the continued survival of the world’s reptiles. Nearly one in five reptilian species are threatened with extinction, with another one in five species classed as Data Deficient. The proportion of threatened reptile species is highest in freshwater environments, tropical regions and on oceanic islands, while data deficiency was highest in tropical areas, such as Central Africa and Southeast Asia, and among fossorial reptiles. Our results emphasise the need for research attention to be focussed on tropical areas which are experiencing the most dramatic rates of habitat loss, on fossorial reptiles for which there is a chronic lack of data, and on certain taxa such as snakes for which extinction risk may currently be underestimated due to lack of population information. Conservation actions specifically need to mitigate the effects of human-induced habitat loss and harvesting, which are the predominant threats to reptiles.
The private and public agencies for nature protection often ask land managers to implement biodiversity conservation plans. Invertebrates constitute a substantial proportion of terrestrial and freshwater biodiversity and are critical to ecosystem functions. However, their inclusion in conservation planning and management is under represented, particularly in the Alps.In this paper we propose a new methodological solution and challenge for the identification of priority areas based on the integration of three approaches: invertebrate multi-taxa based; expert-based; and, GIS-based. The Trentino Province (eastern Italian Alps), was investigated as a case study.The first methodological step was to select a panel of nineteen experts which played a strategic role in the suggestion of 229 species, endangered or of mandatory conservation interest. The second step was to find objective criteria for species prioritisation. These criteria, crossed with the experts taxonomical and ecological knowledge resulted in a list of 70 focal invertebrate species. The third step was to integrate with the GIS-based approach data layers from the habitat requirements of each of the 70 focal species to generate potential spatial-distributional maps. Potential distribution maps gave information about the sites (priority areas) in which the highest number of focal species could concentrate, thus suggesting where to focus future monitoring efforts. Several priority areas resulted outside the protected ones. Alluvial forest and hop-hornbeam woods were the habitats with the highest number of focal species, and thus they represent the habitats of major conservation interest and concern, because they are usually small, fragmented, and near urbanised areas located in the bottom of the valleys. The relatively simple processes involved in species and potential habitat distribution proposed in this paper can be conducted with a minimal amount of data, making it an attractive tool when time and funds are in short supply. (c) 2012 Elsevier GmbH. All rights reserved.
The ecological status of 203 amphibian aquatic breeding sites, selected from the national database of the Societas Herpetologica Italica (SHI), was surveyed in the period 2008-2009 to assess their ecological status. Sites were randomly extracted, after stratification by the three biogeographical regions present in Italy, besides Sardinia and Sicily. The field surveys, conducted by professionals, amateurs and volunteers, showed that since 1979 about 11% of the sites were destroyed or no more suitable for the reproduction of amphibians that bred in the same site in the past. The percentage of destroyed or altered sites was 8%, both in the Mediterranean and Alpine biogeographical regions, and 15% in the Continental one. However, there were no statistical significant differences among the regions, suggesting that the rate of amphibian site loss was similar in different parts of Italy. This nation-wide monitoring project demonstrated that in Italy, during the last thirty years, a relevant proportion of amphibian breeding habitats has been destroyed or altered. The main cause of site alteration were land reclamation and water extraction.
We update the knowledge on the 30 terrestrial reptile species of Socotra, an archipelago well known for its highly endemic flora and fauna. We use the records obtained during several surveys throughout all the islands of the archipelago, carried out between 2007 and 2010, as well as the bibliographic records. We recorded all the known species of terrestrial reptiles for the islands (Chamaeleo monachus, Haemodracon riebeckii, Haemodracon trachyrhinus, Hemidactylus dracaenacolus, H. granti, H. homoeolepis, H. flaviviridis, H. forbesi, H. inintellectus, H. oxyrhinus, H. robustus, H. pumilio, Pristurus abdelkuri, P. guichardi, P. obsti, P. insignoides, P. insignis, P. sokotranus, P. samhaensis, Mesalina balfouri, M. kuri, Hakaria simonyi, Trachylepis socotrana, Pachycalamus brevis, Leptotyphlops filiformis, L. macrurus, L. wilsoni, Typhlops socotranus, Ditypophis vivax, Hemerophis socotrae). We report for the first time the occurrence of Hemidactylus robustus in Samha Island. H. homoeolepis is excluded from the fauna of Abd al-Kuri Island.
The odonatofauna of the Socotra Archipelago is reviewed on the basis of recently collected material and a literature survey. The occurrence of 17 out of the 18 known species from the main island was confirmed between 2007 and 2010, and information on their distribution patterns was obtained. New information on the species occurring on Abd El-Kuri and Samba islands is presented.