Lowland In Italian Free Download
Aura Chupka
Cases of sand fly-borne diseases in the Emilia-Romagna region, such as meningitis caused by Toscana virus and human leishmaniasis, are reported annually through dedicated surveillance systems. Sand flies are abundant in the hilly part of the region, while the lowland is unsuitable habitat for sand flies, which are found in lower numbers in this environment with respect to the hilly areas. In this study, we retrieved sand flies collected during entomological surveillance of the West Nile virus (from 2018 to 2021) to assess their abundance and screen them for the presence of pathogens. Over the four-year period, we collected 3022 sand flies, more than half in 2021. The most abundant sand fly species was Phlebotomus (Ph.) perfiliewi, followed by Ph. perniciosus; while more rarely sampled species were Ph. papatasi, Ph. mascittii and Sergentomyia minuta. Sand flies were collected from the end of May to the end of September. The pattern of distribution of the species is characterized by an abundant number of Ph. perfiliewi in the eastern part of the region, which then falls to almost none in the western part of the region, while Ph. perniciosus seems more uniformly distributed throughout. We tested more than 1500 female sand flies in 54 pools to detect phleboviruses and Leishmania species using different PCR protocols. Toscana virus and Leishmania infantum, both human pathogens, were detected in 5 pools and 7 pools, respectively. We also detected Fermo virus, a phlebovirus uncharacterized in terms of relevance to public health, in 4 pools. We recorded different sand fly abundance in different seasons in Emilia-Romagna. During the season more favorable for sand flies, we also detected pathogens transmitted by these insects. This finding implies a health risk linked to sand fly-borne pathogens in the surveyed area in lowland, despite being considered a less suitable habitat for sand flies with respect to the hilly areas.
The Italian wolf (Canis lupus italicus) population has remained isolated South of the Alps for the last few thousand years. After a strong decline, the species has recolonized the Apennines and the Western Alps, while it is currently struggling to colonize the Eastern Alps. Recently, the species was detected in a lowland park connecting the Northern Apennines to the Central Alps. If the park was able to sustain a net wolf dispersal flow, this could significantly boost the connection with the Eastern Alps and the Dinaric-Balkan population. We investigated the suitability of the park as a functional ecological corridor for the wolf through the unhospitable lowland of Northern Italy. We collected wolf occurrence data in two study areas. We modeled species distribution running a separate ensemble model for each study area and then merging the output of the models to obtain an integrated suitability map. We used this map to identify corridors for the wolf adopting a factorial least-cost path and a cumulative resistant kernel approach. The connectivity models showed that only two corridors exist in the lowland areas between the Northern Apennines and the Central Alps. The Western corridor is a blind route, while the eastern corridor passes through the park and has a continuous course. However, the models also revealed a scarce resilience of corridor connectivity in the passageways between the park and the Apennines and the Prealps, which suggests that urgent management actions are necessary to ensure the future functionality of this important corridor.
Citation: Dondina O, Orioli V, Torretta E, Merli F, Bani L, Meriggi A (2020) Combining ensemble models and connectivity analyses to predict wolf expected dispersal routes through a lowland corridor. PLoS ONE 15(2): e0229261.
A stable re-colonization of the Eastern Alps would be a fundamental step for wolf conservation in Italy [22], since it would increase the genetic exchanges with the Dinaric-Balkan population. This would, in turn, generate new genotypes and increase the genetic diversity of the Italian population, with novel opportunities for local adaptations and evolution [9, 23, 24]. Since the low dispersal flow cannot guarantee a stable connection between the Eastern and the Western Alps, the presence of other connection areas between the Apennines and the Alps would be crucial. In this context, a key role could be played by the recent (2017) detection of the species in the Ticino Natural Park, after 150 years of absence from the lowland areas of Northern Italy. The Ticino Natural Park is a lowland river park longitudinally crossing the highly anthropized Northern Italian plain, which could offer a natural passage for the wolf from the Northern Apennines to the Central Alps.
We used the universal corridor network simulator software UNICOR [50] to model the connectivity corridors for the wolf within the landscape analyzed. The software requires a resistance map layer and a point file containing the geographic coordinates of each source location. To obtain the resistance map, we converted the integrated suitability map into a resistance map representing the permeability of the landscape to species movement using an exponential decay function [34, 51]. Because the wolf is a highly mobile species, an exponential decay function is appropriate for transforming habitat suitability into resistance values. In fact, the use of an exponential conversion means that large portions of the landscape are associated to low resistance while only highly unsuitable areas have high resistance values, leading to more flexibility in corridor location than it would be expected if the resistance map was obtained through a linear conversion of habitat suitability [1, 31]. The most suitable locations of the study area were used as source locations. Specifically, we superimposed a grid of 1 km x 1 km cells to the study area and selected only the cells composed of pixels with suitability values higher than 0.5. The centroids of these cells corresponded to the source locations for connectivity modeling. In particular, while in the Apennines and lowland area we retained all source locations, they were fictitiously rarefied in the Prealps (one centroid every 5 km) to simulate the sporadic presence of the species in this area [20]. Connectivity modeling was developed adopting a factorial least-cost path [25] and a cumulative resistant kernel approach. Factorial least-cost path analysis was used to overcome the limitation of the least-cost path approach associated with the number of sources and target points and to produce a synoptic measure of landscape connectivity [5, 26]. The resistant kernel approach shows the suitability of the whole landscape in supporting the movement of individuals [52]. Specifically, this approach calculates the least-cost dispersal Gaussian kernel around each source location up to a defined distance threshold (corresponding to the maximum dispersal distance of the species). The kernels were then combined through summation to produce a path density map [53], where the value of each pixel of the landscape corresponded to the density of the least cost paths passing through that pixel.
The increase of connectivity in fragmented landscapes is essential to restore or improve the genetic exchanges between animal populations, generate new genotypes and increase genetic diversity [57, 58, 59, 60]. This is fundamental to ensure population resilience to future environmental changes. For the long-term viability of wolves in Europe, and to reach a favorable conservation status of the species (mandatory by [61]), it is crucial to preserve large populations and to enhance the dispersal flow between and within them [12]. In this study, we investigated the potential dispersal flow through the lowland between the Apennine population and the recent established Alpine population in Northern Italy, which could have important implications in increasing the genetic exchanges with the Dinaric-Balkan population and interrupting the isolation of the Italian population that has lasted for thousands of years [13, 17]. To reach this aim, we combined ensemble habitat suitability and connectivity modeling approaches [e.g. 5]. To predict the suitability degree of the whole study area, we integrated two ensemble models implemented in different study areas, in order to obtain a more realistic suitability prediction.
Based on the integration of the two predictive models, approximately one third of the study area was predicted as suitable for the wolf. However, most of the suitable areas were in the hilly and mountain areas of Northern Apennines and Prealps, were forests are widespread and continuous. Conversely, a very small portion of the central lowland area was covered by suitable areas, which were concentrated along the main rivers.
The combination of the results of the two ensemble models showed that rice paddies, arable lands and woodlands were the most important explanatory variables in predicting wolf occurrence. Rice paddies and arable lands had a strongly negative effect on species occurrence, while woodlands had a positive effect. Wolves very often use woodlands or woodland fringes to move or rest because of the shelter provided by forest cover and the high prey densities, whereas open habitats, such as rice paddies and simple arable lands, are usually avoided [55]. The wolf does not avoid agricultural areas just because of the lack of shelter and the low density of prey species, but also due to the anthropogenic disturbance typical of these habitats. Several other studies have shown that anthropogenic pressure is the variable with the most negative effect on wolf occurrence [62, 63, 64, 65]. Moreover, urban centers and agricultural areas, as well as linear infrastructures, such as roads or canals, can be important barriers for wolf movement [64]. The negative effect of such anthropogenic constructs also emerged from our analyses. In fact, the fractional cover of urban areas was another important variable with a strong negative effect on wolf occurrence. A variable with a slightly negative effect on the species was the fractional cover of vineyards. Unlike rice paddies and simple arable lands, vineyards are characterized by a more complex environmental pattern, with small woods scattered in the vineyard matrix. Finally, the relationship between wolf occurrence and the fractional cover of water bodies revealed that areas close to rivers are selected by the species. This choice depends on two fundamental requirements provided by woodland belts bordering rivers in the lowland part of the study area, i.e. protection from human disturbances and the availability of preys [62, 55, 56, 66].
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