Mauro Fois

Using endemic-plant distribution, geology and geomorphology in biogeography: the case of Sardinia (Mediterranean Basin)

The importance of robust systems for classifying biogeographical patterns has been emphasized for its usefulness in designing conservation strategies. For such purposes, the distribution patterns of the endemic flora have often been used. Several studies have identified phytogeographical units within Sardinia (western Mediterranean); however, the main part of the island remains unstudied. Thus, the aim of this study is to lay out a comprehensive biogeographical scheme for Sardinia based on endemic vascular plant distributions, together with geological and geomorphological units. We georeferenced, in a 1-km2 grid cell, the presence of 290 vascular endemic taxa from the literature, herbarium specimens and field investigators’ research. Sardinia was subdivided into 31 homogeneous units through the integration of geological and geomorphological maps and, subsequently, a presence–absence matrix of endemic taxa in each unit was built. Hierarchical cluster analysis was performed to define two levels of biogeographical units (i.e. sectors and subsectors). For each unit the exclusive and differential endemic taxa were identified. For sectors, indicator species were explored by the Indicator Value (Ind Val) analysis and relationships were analysed by quantitative interaction web. A total of six sectors and 22 subsectors were identified. The highest endemic plant richness was found in the Campidanese-Turritano, Sulcitano-Iglesiente and Supramontano sectors, and in the Gennargenteo, Barbaricino, Iglesiente and Sulcitano subsectors. All sectors were characterized by the presence of exclusive, differential and indicator taxa. The interaction analysis showed the highest uniqueness in endemic flora in the Supramontano and Sulcitano-Iglesiente sectors, which hosted a high number of exclusive endemic species. Mostly mountainous sectors/subsectors had higher endemic-species richness compared with lowland ones. The study showed the relevance of geology and geomorphology, together with accurate data on endemic distribution, to define consistent phytogeographical units. Furthermore, the biogeographical scheme presented here helps to define area-based conservation strategies in Sardinia.

The Aichi Biodiversity Target 12 at regional level: an achievable goal?

The Aichi Biodiversity Target 12 aims to prevent the extinction risk of known threatened species and to improve their conservation status by 2020. We present the integrated strategy implemented in the last 10 years for the keystone plant species of Sardinia (Italy, W. Mediterranean Basin), which includes the following activities: conservation status assessment (following the IUCN protocol), ex situ conservation, in situ monitoring and active protection measures. To date, an average of 51.8% of keystone plant species have been subjected to the latter first three activities while, due to the higher costs, only few active conservation measures have been carried out. Considering the activities realised since 2004, we have also predicted the conservation effectiveness towards 2020 and have elaborated an index to evaluate it. Halfway through the strategic plan, we argue that more efforts are needed to guarantee the effective conservation of all threatened plants in Sardinia.

Global analyses underrate part of the story: finding applicable results for the conservation planning of small Sardinian islets’ flora

Although many studies have addressed island biogeography, the biodiversity of very small islets has mostly been ignored due to the lack of high-resolution data. We analysed the vascular plant taxa distribution pattern of 81 satellite islets scattered around Sardinia, the second largest island in the Mediterranean Basin. Power models were used to determine the influence of environmental and anthropogenic factors on both endemic and non-endemic species richness. Analyses of the distribution pattern highlighted the high endemism rate in these islets. In addition, reliable results for conservation, such as correlations with land use diversity, climate and human presence, were found only when categorising the islets by their environmental characteristics instead of their geographical position. This study of a representative set of Mediterranean islets contributes to the knowledge base about the controversial role of very small islets in biological conservation. Large-scale analyses have often underrated their importance and we therefore suggest that local studies about their conservation planning are needed worldwide.

Using extinctions in species distribution models to evaluate and predict threats: a contribution to plant conservation planning on the island of Sardinia

Recent extinction rates suggest that humans are now causing the sixth mass extinction, and the Mediterranean islands are at the forefront of many of the environmental issues involved. This study provides an alternative approach for investigating documented local plant extinctions that occurred in Sardinia (western Mediterranean) during the last half century. A total of 190 local extinctions of 62 plant species were used to investigate the independent effects of eight ecological and anthropogenic variables and to model the areas of potential extinctions where plant conservation efforts could be focused. If all analysed plant species were considered together, ecological factors explained local extinctions more than anthropogenic factors. The independent effects of each factor considerably varied among species of different lifeforms and altitude ranges. Accordingly, distribution models of local extinctions outscored areas that are potentially rich in plant species with conservation interest, but which are particularly affected by humans. This paper suggests a reproducible, operational framework for analysing which extinction factors may play important roles in similar contexts and where they might be relevant.

Current and future effectiveness of the Natura 2000 network for protecting plant species in Sardinia: a nice and complex strategy in its raw state?

Sardinia hosts 186 endemic plant species and represents an important centre for Mediterranean biodiversity. In view of the threats facing its flora, 27 terrestrial vascular plants have been listed in international regulations and 124 sites designated for species and habitat conservation. This study analyses gaps in the Natura 2000 network and the current and future distribution of four representative plants. Each plant population was georeferenced and the effectiveness of the Natura 2000 network was compared according to conservation status and distribution. Future species distributions were modelled by considering current climatic conditions and future scenarios. In apparent discordance with other results, we found that the Natura 2000 network represents most plant species well. This research shows a forward-looking survey on the regional effectiveness of protection measures which led us to confirm the need to enhance the current state of the Natura 2000 network by implementing local legislation and regulations.

Disentangling the influence of environmental and anthropogenic factors on the distribution of endemic vascular plants in Sardinia

Due to the impelling urgency of plant conservation and the increasing availability of high resolution spatially interpolated (e.g. climate variables) and categorical data (e.g. land cover and vegetation type), many recent studies have examined relationships among plant species distributions and a diversified set of explanatory factors; nevertheless, global and regional patterns of endemic plant richness remain in many cases unexplained. One such pattern is the 294 endemic vascular plant taxa recorded on a 1 km resolution grid on the environmentally heterogeneous island of Sardinia. Sixteen predictors, including topographic, geological, climatic and anthropogenic factors, were used to model local (number of taxa inside each 1 km grid cell) Endemic Vascular Plant Richness (EVPR). Generalized Linear Models were used to evaluate how each factor affected the distribution of local EVPR. Significant relationships with local EVPR and topographic, geological, climatic and anthropogenic factors were found. In particular, elevation explained the larger fraction of variation in endemic richness but other environmental factors (e.g. precipitation seasonality and slope) and human-related factors (e.g. the Human Influence Index (HII) and the proportion of anthropogenic land uses) were, respectively, positively and negatively correlated with local EVPR. Regional EVPR (number of endemic taxa inside each 100 m elevation interval) was also measured to compare local and regional EVPR patterns along the elevation gradient. In contrast to local, regional EVPR tended to decrease with altitude partly due to the decreasing area covered along altitude. The contrasting results between local and regional patterns suggest that local richness increases as a result of increased interspecific aggregation along altitude, whereas regional richness may depend on the interaction between area and altitude. This suggests that the shape and magnitude of the species-area relationship might vary with elevation. This work provides—for the first time in Sardinia—a comprehensive analysis of the influence of environmental factors on the pattern of EVPR in the entire territory, from sea level to the highest peaks. Elevation, as well as other environmental and human-related variables, were confirmed to be influencing factors. In addition, variations of EVPR patterns at regional-to-local spatial scales inspire next investigations on the possible interaction between elevation and area in explaining patterns of plant species richness.

Identifying and assessing the efficiency of different networks of a fine-scale hierarchy of biodiversity hotspots

Background: For prioritising practical conservation measures in areas of high endemic plant diversity, a fine-scale hierarchy of sites needs to be established. In this context, conservation sites designed at local and regional levels are considered a network of interconnected areas. Aims: The main aim was to identify two hierarchical levels of a network of conservation sites, called ‘micro hotspots’ and ‘nano hotspots’, and test their efficiency for achieving conservation objectives across the island of Sardinia, Mediterranean Basin. Methods: We analysed the spatial distribution of endemic vascular plant species (EVPS) richness. Additionally, the area, perimeter, connectivity and surplus costs for the protection of all endemic plant populations were used as ranking criteria for a hierarchical classification. Results: We identified eight micro hotspots and 82 nano hotspots. Amongst the three possible solutions compared, the integrated network of micro and nano hotspots resulted in more effective conservation than any of the single-level network solutions with only micro or nano hotspots, and it included 89% of all EVPS in a relatively small areal extent. Conclusions: The identification of hotspot networks at the regional level allowed determining priority areas to implement conservation efforts for EVPS. The integration of micro hotspots with nano hotspots resulted in the most effective network from both conservation and economic perspectives. We suggest that our model may provide an effective tool for integrated and effective conservation actions in the Mediterranean Basin.

The influence of natural and anthropogenic factors on the floristic features of the northern coast Nile Delta in Egypt

Abstract The Egyptian Mediterranean sand dunes are being lost due to recent excessive unplanned anthropogenic interventions that caused a modification in floristic composition. The present study provides a description of the floristic inventory and plant clusters in coastal dunes in relation to natural and human factors. Floristic sampling was carried out in nine transects along Nile Delta coast, a total of 55 plots were randomly placed and data on natural and anthropogenic factors were measured for each plot. Agglomerative Hierarchical Cluster allowed to identify four plant clusters: (A) Elymus farctus-Silene succulenta, (B) Echinops spinosus-Moltkiopsis ciliata, (C): Stipagrostis lanata-Echium angustifolium and (D): Lycium schweinfurthii-Asparagus stipularis. Fish farming, ceramic industry, trampling, agriculture, urbanization, magnesium, total nitrogen, potassium, calcium and organic matter were identified as the most significant key factors for the definition of plant clusters by Canonical Correspondence Analysis. Variance partitioning confirmed that 40% of the variance was explained by both natural and anthropogenic factors. In particular, anthropogenic factors explained only 9% while natural variables 2% of the total variance, whereas the combined shared effect was 29%. The information in this study enables us to establish an effective conservation strategy to prevent further declines in plant diversity along coastal dunes.

The impact of climatic variations on the reproductive success of Gentiana lutea L. in a Mediterranean mountain area

Increases in temperature have been predicted and reported for the Mediterranean mountain ranges due to global warming and this phenomenon is expected to have profound consequences on biodiversity and ecosystem functioning. We hereby present the case of Gentiana lutea L. subsp. lutea, a rhizomatous long-lived plant living in Central-Southern Europe, which is at the edge of its ecological and distributional range in Sardinia. Concretely, we analysed the reproductive success experienced during three phenological cycles (2013/2014, 2014/2015 and 2015/2016) in four representative populations, with particular attention to the phenological cycle of 2014/2015, which has been recorded as one of the warmest periods of the last decades. The Smirnov-Grubbs test was used to evaluate differences in temperature and precipitation regimes among historical data and the analysed years, while the Kruskal-Wallis followed by the Wilcoxon test was used to measure differences between anthesis and reproductive performances among cycles and populations. In addition, generalised linear models were carried out to check relationships between climate variables and reproductive performance. Significant differences among climate variables and analysed cycles were highlighted, especially for maximum and mean temperatures. Such variations determined a non-flowering stage in two of the four analysed populations in 2014/2015 and significant differences of further five reproductive traits among cycles. These results confirmed that in current unstable climatic conditions, which are particularly evident in seasonal climates, reproductive success can be a sensitive and easily observable indicator of climatic anomalies. Considering the importance of this issue and the ease and cost-effectiveness of reproductive success monitoring, we argue that research in this sense can be a supporting tool for the enhancement of future crucial targets such as biodiversity conservation and the mitigation of global warming effects.

The genetic structure and diversity of Gentiana lutea subsp. lutea (Gentianaceae) in Sardinia: further insights for its conservation planning

ABSTRACT Knowledge of the levels of genetic diversity and of the spatial genetic structure of plant species is important to ensure their effective management and conservation, especially in the case of endangered species. Gentiana lutea L. subsp. lutea is a long-lived plant which occurs in central and southern European mountains. It has a long-standing history of human exploitation, mainly in the liqueur and in the pharmaceutical industries and it is currently listed in the EU Habitats Directive 92/43/EEC Annex V. Mainly due to a prolonged root harvesting, its current distribution range in Sardinia consists of only a few groups of individuals limited to small areas of the Gennargentu massif (Central-Eastern area of the island). In this study, we investigated the levels of genetic diversity and the genetic structure of the species in Sardinia. We used AFLP (amplified fragment length polymorphism) markers to investigate the genetic variability of 182 samples from 13 subpopulations. A total of 433 fragments were detected, of which 75.5% were polymorphic. The levels of genetic diversity were generally high, but they tended to decrease in smaller subpopulations. Of the genetic variability 88% was found within subpopulations, while the genetic structure among them was fairly weak. In order to ensure the survival of these subpopulations, especially the smaller ones, ex situ and in situ management actions should be planned, such as the long term conservation of its seeds in germplasm repositories and their population reinforcements and monitoring.