Connectivity in a real fragmented landscape: distance vs movement model based approaches.

Graph theory derived models and measures are increasingly being used to quantify landscape connectivity in order to contribute to conservation biology and management. This is particularly relevant in the case of real landscapes in which local actions may have crucial consequences for maintaining biodiversity on large scale. A number of graphs were compared sharing an identical node weight definition and whose link weights representing functional patch-connectivity, were derived from conceptually different approaches. Habitat suitability was taken into account. Calculated patch-connectivity was compared between all the graphs and these differences, evaluated by a set of indices describing network properties at the element structure level, were investigated

Predicting wild boar damages to croplands in a mosaic of agricultural and natural areas

Crop damages by wildlife is a frequent form of human-wildlife conflict. Identifying areas where the risk of crop damages is highest is pivotal to set up preventive measures and reduce conflict. Species distribution models are routinely used to predict species distribution in response of environmental changes. The aim of this paper was assessing whether species distribution models can allow to identify the areas most at risk of crop damages, helping to set up management strategies aimed at the mitigation of human-wildlife conflicts. We obtained data on wild boar Sus scrofa damages to crops in the Alta Murgia National Park, Southern Italy, and related them to landscape features, to identify areas where the risk of wild boar damages is highest. We used MaxEnt to build species distribution models. We identified the spatial scale at which landscape mostly affects the distribution damages, and optimized the regularization parameter of models, through an information-theoretic approach based on AIC. Wild boar damages quickly increased in the period 2007-2011; cereals and legumes were the crops more affected. Large areas of the park have a high risk of wild boar damages. The risk of damages was related to low cover of urban areas or olive grows, intermediate values of forest cover, and high values of shrubland cover within a 2-km radius. Temporally independent validation data demonstrated that models can successfully predict damages in the future. Species distribution models can accurately identify the areas most at risk of wildlife damages, as models calibrated on data collected during only a subset of years correctly predicted damages in the subsequent year

Impact of woody encroachment on soil organic carbon and nitrogen in abandoned agricultural lands along a rainfall gradient in Italy

Land use changes represent one of the most important components of global environmental change andhave a strong influence on carbon cycling. As a consequence of changes in economy during the last century, areas of marginal agriculture have been abandoned leading to secondary successions. The encroachment of woody plants into grasslands, pastures and croplands is generally thought to increase the carbon stored in these ecosystems even though there are evidences for a decrease in soil carbon stocks after land use change. In this paper, we investigate the effects of woody plant invasion on soil carbon and nitrogen stocks along a precipitation gradient (200–2,500 mm) using original data from paired experiment in Italian Alps and Sicily and data from literature (Guo and Gifford Glob Change Biol 8(4):345–360, 2002). We found a clear negative relationship (-0.05% C mm-1) between changes in soil organic carbon and precipitation explaining 70% of the variation in soil Cstocks after recolonization: dry sites gain carbon (up to? 67%) while wet sites lose carbon (up to -45%). In our data set, there seem to be two threshold values for soil carbon accumulation: the first one is 900 mm of mean annual rainfall, which separates the negative from the positive ratio values; the second one is 750 mm, which divides the positive values in two groups of sites. Most interestingly, this threshold of 750 mm corresponds exactly to a bioclimatic threshold: sites with\750 mm mean annual rainfall is classified as thermo-mediterranean sites, while the ones [750 mm are classified as mesomediterranean sites. This suggests that apart from rainfall also temperature values have an important influence on soil carbon accumulation after abandonment. Moreover, our results confirmed that the correlation between rainfall and trend in soil organic carbon may be related to nitrogen dynamics: carbon losses may occur only if there is a substantial decrease in soil nitrogen stock which occurs in wetter sites probably because of the higher leaching

Mosquitoes LTR Retrotransposons: A Deeper View into the Genomic Sequence of Culex quinquefasciatus

A set of 67 novel LTR-retrotransposon has been identified by in silico analyses of the Culex quinquefasciatus genome using the LTR_STRUC program. The phylogenetic analysis shows that 29 novel and putatively functional LTR-retrotransposons detected belong to the Ty3/gypsy group. Our results demonstrate that, by considering only families containing potentially autonomous LTR-retrotransposons, they account for about 1% of the genome of C. quinquefasciatus. In previous studies it has been estimated that 29% of the genome of C. quinquefasciatus is occupied by mobile genetic elements

Cambiamenti del paesaggio nel sito Natura 2000 “Murgia Alta" e frammentazione delle praterie aride

This research aimed at evaluating the effectiveness of the process of Natura 2000 implementation at the national and regional levels in avoiding the loss and fragmentation of dry grasslands in the SCI/SPA IT9120007 “Murgia Alta” (Apulia region, Italy). Based on a comparison between Corine Land Cover maps for years 1990, 1999, 2006, historic habitat fragmentation was analysed for the whole site extent by means of identification and quantification of fragmentation geometries and size variation intervals of the remaining focal habitat patches. Based on a 2006-2007 high-resolution land-use map, the current level of habitat fragmentation was assessed in 8 transects by a quantitative analysis of the landscape pattern, and by integrating indexes representing both the global and the local approach to landscape pattern analysis. The results indicate that heavy habitat loss and fragmentation occurred during the 1990-1999 period, mostly due to conversion to arable land. This period approximately corresponds to a delay in transposing the UE “Habitats” Directive at the national and regional levels. Negligible changes can be detected, at this scale, for the 1999-2006 period, after Natura 2000 site selection and boundary definition had been approved. Natura 2000 boundary definition in the study area can be considered as appropriate, as a very small surface of the focal habitat is found outside of Natura 2000. An analysis at a finer scale and the joint use of different indices highlight the spatial variability of the current fragmentation and provides indications of the pressure nearby the focal habitat. Besides quantifying the recent change and the current status of dry grasslands in the study area, this analysis shows that the integration of complementary information derived from different approaches and the availability of maps at different spatial scales are necessary to monitoring habitat fragmentation, both within and outside Natura 2000, an essential element for assessing the effectiveness of conservation policies

Connectivity in a real fragmented landscape: distance vs movement model based approaches

Graph theory derived models and measures are increasingly being used to quantify landscape connectivity in order to contribute to conservation biology and management. This is particularly relevant in the case of real landscapes in which local actions may have crucial consequences for maintaining biodiversity on large scale. A number of graphs were compared sharing an identical node weight definition and whose link weights representing functional patch-connectivity, were derived from conceptually different approaches. Habitat suitability was taken into account. Calculated patch-connectivity was compared between all the graphs and these differences, evaluated by a set of indices describing network properties at the element structure level, were investigated

Landscape fragmentation as an indicator of coastal landscape quality: an application along the Apulian coast (southern Italy),45. MININNI M., MINUNNO F., LERONNI V., TARANTINO C. MAIROTA P..(2007), Landscape fragmentation as an indicator of coastal landscape quality: an application along the Apulian coast (southern Italy),

This work has being carried out within the framework of the IMCA (Integrated Monitoring of Coastal Areas) Research Project, among the activities aimed at drawing coastal landscape quality maps through the use of indicators derived from satellite RS images. The overall research project, moving from the experience of the European Landscape Convention, tackles the landscape quality issue via a multi temporal and spatial scale approach. The present contribution focuses on fragmentation as this phenomenon, as well as the loss of heterogeneity, initiated by urban settlement processes of dislocation and diffusion, represents the main cause of the landscape ecological efficiency decrease, of the area decay and of the beginning of diseconomy in its management (Forman, 1995). In order to quantify fragmentation, at a given spatial scale (defined in terms of both grain and extent), a set of LPI (ED, LSI, ENN_AM, PLADJ, MESH, SHDI) was computed at the landscape level on a sample plot population, extracted via an unaligned random samplingprocedure from the whole southernmost part of the Apulian peninsula (Southern Italy) and for which intepretation of recent aerial photographs had already been performed within the framework of the IMCA research project (Miacola et al. 2006). The same protocol was applied to categorical maps of the same area, derived, both by past aerial photointerpretation and by (unsupervided and supervised) segmentation, from medium (Landsat TM) resolution satellite images of two time steps. Preliminary results are encouraging in many respects. The distribution analysis performed on the indexes computed on the different data sets show, for this particular landscape at the given scale, a significant trend towards a normal distribution model, thus contributing to the ongoing debate (Remmel and Csillag 2003) on the uncertainties about the possibility to statistically compare indexes computed in different times and places, deriving by the lack of knowledge about their distribution. Principal component analysis performend on the indexes obtained from the different data sets, yields the ordination of sample plots along a fragmentation gradient, that migth be used to construct framentation intensity maps at the subregional scale, as well as to interpreting the change processes and obtain intelligent maps based upon the integration of field (aerial-photo interpetation) and and RS data, thus achieving the twofold purpouse of performing a phenomenological study aimed both at tmodelling coastal landscape transformations and identifying new survey categories that may have the temporal dimension as a reading parameter (e.g.. speed of change). As far as the relations between the indexes computed on the different data sets are concerned, they allow for the assessment of the potentials for using unsupervised categorical maps for the description and monitoring of landscapes fragmentation, as well as for testing hypoteses concerning fragmentation scaling relations in both space and time (Wu, 2004; Jelinski and Wu 1996

Using spatial simulations of habitat modification for adaptive management of protected areas: Mediterranean grassland modification by woody plant encroachment.

Spatial simulation may be used to model the potential effects of current biodiversity approaches on future habitat modification under differing climate change scenarios. To illustrate the approach, spatial simulation models, including landscape-level forest dynamics, were developed for a semi-natural grassland of conservation concern in a southern Italian protected area, which was exposed to woody vegetation encroachment. A forest landscape dynamics simulator (LANDIS-II) under conditions of climate change, current fire and alternative management regimes was used to develop scenario maps. Landscape pattern metrics provided data on fragmentation and habitat quality degradation, and quantified the spatial spread of different tree species within grassland habitats. The models indicated that approximately one-third of the grassland area would be impacted by loss, fragmentation and degradation in the next 150 years. Differing forest management regimes appear to influence the type of encroaching species and the density of encroaching vegetation. Habitat modifications are likely to affect species distribution and interactions, as well as local ecosystem functioning, leading to changes in estimated conservation value. A site-scale conservation strategy based on feasible integrated fire and forest management options is proposed, considering the debate on the effectiveness of protected areas for the conservation of ecosystem services in a changing climate. This needs to be tested through further modelling and scenario analysis, which would benefit from the enhancement of current modelling capabilities of LANDIS-II and from combination with remote sensing technologies, to provide early signals of environmental shifts both within and outside protected areas