Luca Malatesta

Systemic Spatial Decision Support Systems: An integrated, computer‐aided tool for biodiversity conservation

Abstract In the last decades, biodiversity is facing many threats related to the expansion and development of human populations. With the aim of mainstreaming conservation together with sustainable development, several conflicting necessities related to the economic, social, environmental and institutional objectives of the society have to be balanced within complex decision-making contexts. Conventional approaches hardly cope with these demands, and therefore conceptual models are required for understanding ecosystems form and functions and how human activities impact on them. International organisations committed to conservation and development initiatives have recognised the importance and effectiveness of an integrated, participative and adaptive approach to ecosystem management. In this perspective, computerised tools to facilitate an overall view and support informed and aware decisions are required. The Systemic Spatial Decision Support System, here presented, is a comprehensive tool for a holistic, multi-scale, spatially explicit and tailor-made approach to such complex decisional environments. The core methodology builds upon several years of experience in international conservation and development projects supported by the Italian Development Cooperation, and is complemented by an ad hoc, easily customisable software shell. Its characteristics provide an ideal framework for an effective administration of biodiversity conservation initiatives, as well as for training and consolidating expert knowledge.

Vegetation mapping from high-resolution satellite images in the heterogeneous arid environments of Socotra Island (Yemen)

Abstract Socotra Island (Yemen), a global biodiversity hotspot, is characterized by high geomorphological and biological diversity. In this study, we present a high-resolution vegetation map of the island based on combining vegetation analysis and classification with remote sensing. Two different image classification approaches were tested to assess the most accurate one in mapping the vegetation mosaic of Socotra. Spectral signatures of the vegetation classes were obtained through a Gaussian mixture distribution model, and a sequential maximum a posteriori (SMAP) classification was applied to account for the heterogeneity and the complex spatial pattern of the arid vegetation. This approach was compared to the traditional maximum likelihood (ML) classification. Satellite data were represented by a RapidEye image with 5 m pixel resolution and five spectral bands. Classified vegetation relevés were used to obtain the training and evaluation sets for the main plant communities. Postclassification sorting was performed to adjust the classification through various rule-based operations. Twenty-eight classes were mapped, and SMAP, with an accuracy of 87%, proved to be more effective than ML (accuracy: 66%). The resulting map will represent an important instrument for the elaboration of conservation strategies and the sustainable use of natural resources in the island.

Evidence of Facilitation Cascade Processes as Drivers of Successional Patterns of Ecosystem Engineers at the Upper Altitudinal Limit of the Dry Puna

Facilitation processes constitute basic elements of vegetation dynamics in harsh systems. Recent studies in tropical alpine environments demonstrated how pioneer plant species defined as “ecosystem engineers” are capable of enhancing landscape-level richness by adding new species to the community through the modification of microhabitats, and also provided hints about the alternation of different ecosystem engineers over time. Nevertheless, most of the existing works analysed different ecosystem engineers separately, without considering the interaction of different ecosystem engineers. Focusing on the altitudinal limit of Peruvian Dry Puna vegetation, we hypothesized that positive interactions structure plant communities by facilitation cascades involving different ecosystem engineers, determining the evolution of the microhabitat patches in terms of abiotic resources and beneficiary species hosted. To analyze successional mechanisms, we used a “space-for-time” substitution to account for changes over time, and analyzed data on soil texture, composition, and temperature, facilitated species and their interaction with nurse species, and surface area of engineered patches by means of chemical analyses, indicator species analysis, and rarefaction curves. A successional process, resulting from the dynamic interaction of different ecosystem engineers, which determined a progressive amelioration of soil conditions (e.g. nitrogen and organic matter content, and temperature), was the main driver of species assemblage at the community scale, enhancing species richness. Cushion plants act as pioneers, by starting the successional processes that continue with shrubs and tussocks. Tussock grasses have sometimes been found to be capable of creating microhabitat patches independently. The dynamics of species assemblage seem to follow the nested assemblage mechanism, in which the first foundation species to colonize a habitat provides a novel substrate for colonization by other foundation species through a facilitation cascade process.

Analysing the relationship between land units and plant communities: The case of Socotra Island (Yemen)

The ecological land scape classification (ELC) allows the identification of homogeneous land units (LUs), which are fundamental for investigation and management purposes. ELC is particularly relevant in international cooperation programmes targeting areas characterized by very scarce and scattered thematic information. In this study, three techniques are compared to find the best classification of LUs of Socotra Island (Yemen): a Self-Organizing Map neural network, the Clustering LARge Applications method and a Two-Step clustering algorithm. In this way, three LU maps of Socotra Island were produced and the relationship between LUs and plant communities, as identified by a phytosociologiacl investigation, was analysed. Based on evaluation procedures, TS method emerged as the most suitable being able to better discriminate the plant communities so as to reach a trade-off between classification complexity and class homogeneity. Even though the identification of LUs depends on the selection of the classification method and criteria, the scale adopted and the specific management and planning purposes, this study represents a contribution towards a standardization of ecological classification systems thanks also to the worldwide availability of georeferenced environmental data.

The interplay of land forms and disturbance intensity drive the floristic and functional changes in the dry Puna pastoral systems (southern Peruvian Andes)

In the Peruvian highlands, climate change and inadequate management are causing land degradation and collapse of the pastoral system. Our research project was aimed at assessing the impact of grazing on dry Puna ecosystem, as understanding and predicting vegetation changes in harsh environments in the face of different disturbance regimes is required for aware and effective management. The study area was the Salinas and Aguada Blanca National Reserve. Two experimental areas were selected, characterized by deep soils with gentle slopes and by shallow soils with steeper slopes. In each area, sites with low and high disturbance regimes were identified, and vegetation was sampled using 10 × 10 m plots. The results indicated that the environmental constraints have a marked influence on the species composition, while disturbance quantitatively affects diversity. The floristic changes observed under different disturbance intensities are mainly related to the functional differentiation of the plant communities and to the decrease in vegetation cover. These processes pose a serious risk to the livelihood of the local people, because they can lead to the loss of biodiversity and economic value of pastures, as well as to soil erosion.

Long-term cropland abandonment does not lead per se to the recovery of semi-natural herb communities deemed habitats of community interest

Abstract Anogramma leptophylla is one of the rarest fern species in Balkan Peninsula. In Croatia, several localities were noted prior to this study, when its presence was confirmed with a discovery of a small population on the island of Mljet (Southern Adriatic). This was, after almost 80 years, the first reliable finding of this species along Eastern Adriatic. The establishment of A. leptophylla on the western part of the island of Mljet may be attributable to certain favourable environmental conditions, but essentially to higher air and soil humidity. Its unusual bryophyte-like life strategy, with short-living annual sporophytes, facilitates its survival under Mediterranean climate, generally unfavourable for pteridophytes.