No abstract

Rodríguez-Merino, A., Fernández-Zamudio, R. & García-Murillo, P.2017. An invasion risk map for non-native aquatic macrophytes of the Iberian Peninsula. Anales Jard. Bot. Madrid 74(1): e055.Freshwater systems are particularly susceptible to non-native organisms, owing to their high sensitivity to the impacts that are caused by these organisms. Species distribution models, which are based on both environmental and socio-economic variables, facilitate the identification of the most vulnerable areas for the spread of non-native species. We used MaxEnt to predict the potential distribution of 20 non-native aquatic macrophytes in the Iberian Peninsula. Some selected variables, such as the temperature seasonality and the precipitation in the driest quarter, highlight the importance of the climate on their distribution. Notably, the human influence in the territory appears as a key variable in the distribution of studied species. The model discriminated between favorable and unfavorable areas with high accuracy. We used the model to build an invasion risk map of aquatic macrophytes for the Iberian Peninsula that included results from 20 individual models. It showed that the most vulnerable areas are located near to the sea, the major rivers basins, and the high population density areas. These facts suggest the importance of the human impact on the colonization and distribution of non-native aquatic macrophytes in the Iberian Peninsula, and more precisely agricultural development during the Green Revolution at the end of the 70's. Our work also emphasizes the utility of species distribution models for the prevention and management of biological invasions.

In order to prevent future biological invasions, it is crucial to know non-native species distributions. We evaluated the potential global distribution of Azolla filiculoides, a free-floating macrophyte native to the Americas by using species distribution models and niche equivalency tests to analyze the degree of niche overlap between the native and invaded ranges of the species. The models were projected under two future emission scenarios, three global circulation models and two time periods. Our results indicate a possible niche shift between the distribution ranges of the species, indicating that A. filiculoides can adapt to novel environmental conditions derived from climatic differences during the invasion process. Our models also show that the future potential distribution of A. filiculoides will decrease globally, although the species could colonize new vulnerable regions where it is currently absent. We highlight that species occurrence records in the invaded area are necessary to generate accurate models, which will, in turn, improve our ability to predict potential invasion risk areas.

No abstract

Characterizing zone fragility is a significant challenge when managing protected natural areas, but it must be prioritized in conservation efforts. The most commonly employed methodology is to rely on criteria established by experts, which can introduce subjectivity. However, more objective approaches should be used when developing conservation plans. This study proposes one methodology for classifying zone vulnerability within a protected natural area, taking as a study case a temporal pond network located in SW Spain; threatened species of aquatic plants were used as a bioindicators. Spatial data were analysed using geographic information systems (GIS), and potentially vulnerable zones were identified using multicriteria decision analysis and, more specifically, the weighted overlay method. Criteria weights were determined using species distribution models, via the maximum entropy algorithm (MaxEnt). The purpose was to avoid artificial bias in decisionmaking. The analysis indicated that 42.04% of the study area was highly vulnerable. In contrast, only the 14.34% of the study area was at very low risk, meaning it can help maintain pond network biodiversity. These results indicate that potentially vulnerable and crucial zones can be identified using GIS, facilitating the establishment of conservation priorities in a complex system. This methodology could be useful for prioritizing and implementing management and conservation efforts focused on unique species and habitats in protected natural areas. Highlights (for review)