Central-eastern Sardinia Research Articles

Centranthus pontecorvi (Valerianaceae) a new species from Sardinia

The species of Centranthus (Valerianaceae) belonging to C. sect. Nervosae are investigated. They are currently represented by C. trinervis from southern Corsica and C. amazonum from central-eastern Sardinia. In addition, a new isolated population has been discovered in southwestern Sardinia, which is morphologically and ecologically very differentiated from the other two known species. This population can be treated as new species, named C. pontecorvi, growing on screes constituted by Cambrian metacarbonates, localized in the Sulcitano-Iglesiente biogeographic sector. For each species, a detailed description and a new illustration based on living and herbarium materials are provided. Information on typification, synonymy, phenology, ecology, distribution, conservation status, and a list of examined herbarium specimens is also given. Furthermore, an updated identification key utilising the diagnostic traits of these three species has been elaborated.

Towards an Ecosystem of Innovation for Inner Areas: A Research Plan for the Tourist Development on the Ogliastra Region (Sardinia, Italy)

The global project e.INS ecosystem - Ecosystem of Innovation for Next generation Sardinia is intended to support Sardinian small and medium enterprises (SMEs)’ innovation and sustainability: in particular, our research group focused on SMEs operating in the tourism and cultural heritage sector, highlighting those operating in marginal places. To achieve this, proposing a network between different municipalities is strongly recommended to create a single destination equipped with compelling storytelling. Following the slow tourism basis as a catalyst for inner areas’ development, the present work illustrates a still-in-the-making project on the case study of the Ogliastra, i.e., a historical-geographical region located in central-eastern Sardinia: the aim is to first propose a strategy of destination storytelling through a coastal-inner areas relationship, and then engage the entrepreneurial tourism reality in such a spatial aggregation. Starting from Tortolì port, we proposed a concept of itinerary for slow exploration of all the municipalities in the Ogliastra’s Rio Pardu Valley system, rich in natural landscape, heritage and Genius Loci. Creating a coastal area-inner area type destination could lead to benefits for the entrepreneurial landscape of the Ogliastra Valley, also strengthening the SMEs of the coastal area.

Reintroductions of the Corsican Red Deer (Cervus elaphus corsicanus): Conservation Projects and Sanitary Risk

Simple SummaryReintroductions are important tools to achieve the long-term conservation of endangered species; however, these projects are dangerous for translocated animals. Reintroduced animals face novel habitats where food availability and secure resting sites are unknown, and in this context, such animals likely engage in long exploratory movements. Furthermore, reintroductions can be dangerous for domestic and wild animals inhabiting the reintroduction site due to the potential risk of catching diseases carried by reintroduced animals. Our study aimed to evaluate the spatial behavior of reintroduced Corsican red deer in central-eastern Sardinia and, on the basis of the obtained results, build a species distribution model to forecast the expansion of reintroduced deer and plan future reintroduction projects. Furthermore, we evaluated the sanitary risk for domestic animals (sheep) linked to Bluetongue virus potentially carried by deer. Our results highlighted the great habitat suitability of central–eastern Sardinia for Corsican red deer. However, deer are healthy carriers of Bluetongue virus, as confirmed by health analyses we performed on captured animals in the source areas. Particular attention in reintroduction planning is needed to avoid any negative impacts on domestic or wild animals of conservation measures.The Corsican red deer is an endangered subspecies that needs artificial translocation projects to gain its complete recovery with the formation of viable, interconnected populations. Between 2007 and 2017, we performed two reintroduction projects in four sites in central–eastern Sardinia via tracking 32 deer by means of GPS/GSM radiotelemetry. On the basis of the obtained results, we built a species distribution model (SDM) using MaxEnt software, selecting 200 random points from the merged deer core areas as presence data. Furthermore, to evaluate the sanitary risk linked to artificial translocations, we analyzed deer positivity to Bluetongue virus (BTV) in the founder populations. The SDM showed a high deer capability to colonize central–eastern Sardinia, but it also showed the possibility of spreading BTV to domestic sheep because sanitary analyses confirmed the virus’ presence in the founder populations. Our main conclusion was that reintroductions are effective tools for the long-term conservation of the Corsican red deer, as long as sanitary risks are minimized by means of sanitary monitoring of translocated deer.

Land Use in Central-Eastern Sardinia during the Bronze Age. Environmental Study, Experimental Archaeology and Ethnographic Comparison as Hypothesis of Demographic Calculation

Land Use in Central-Eastern Sardinia during the Bronze Age. Environmental Study, Experimental Archaeology and Ethnographic Comparison as Hypothesis of Demographic Calculation

Evolution of Deep-Seated Gravitational Slope Deformations in Relation with Uplift and Fluvial Capture Processes in Central Eastern Sardinia (Italy)

Connections between Plio-Pleistocenic tectonic activity and geomorphological evolution were studied in the Pardu Valley and Quirra Valley (Ogliastra, East Sardinia). The intensive Quaternary tectonic activity in Sardinia linked to the opening of the Tyrrhenian Basin is known. In Eastern Sardinia, it manifests with an uplift that is recorded by geomorphological indicators, such as deep-seated gravitational slope deformation, fluvial captures, engraved valleys, waterfalls, and heterogeneous water drainage. The Pardu River flows from the NW toward the SE and then abruptly changes direction toward the NE. At this point, a capture elbow adjacent to the current head of the Quirra River is well developed. The Quirra River, in its upstream part, flows at altitudes approximately 200 m higher than the Pardu River. It also shows an oversized and over-flooded valley with respect to the catchment area upstream. This setting indicates that the Pardu River, which previously flowed south along the Quirra River, was captured by the Pelau River. We analyzed long-term landslides with lateral spreading and sackung characteristics, which involve giant carbonate blocks and underlying foliated metamorphites in both valleys. The use of LiDAR, high-resolution uncrewed aerial vehicle digital photogrammetry (UAV-DP), and geological, structural, and geomorphological surveys enabled a depth morphometric analysis and the creation of interpretative 3D models of DGSDs. Space-borne interferometric synthetic aperture radar (InSAR) data using ERS and Sentinel-1 satellites identified downslope movement of up to 20 mm per year in both Pardu Valley flanks. Multi-source and multi-scale data showed that the state of activity of the DGSDs is closely linked to the geomorphological evolution of the catchment areas of the Rio Pardu and Rio Quirra. The intense post-capture erosion acted in the Rio Pardu Valley, giving it morphometric characteristics that were favorable to the current evolution of the DGSDs, while the Rio Quirra Valley presents paleo-DGSDs that have been fossilized by pre-capture terraced alluvial deposits.

Plant Diversity in Sardinian Mountain Rangelands: Analysis of Its Relationships with Grazing, Land Management, and Pastoral Value

In this study, we analyzed the effects of grazing on native and endemic plant diversity, as well as its relationship with pastoral value along a gradient of abiotic and biotic factors and types of land management in a mountainous area of central-eastern Sardinia, Italy. Plant diversity was estimated by conducting a floristic survey within plots. In total, 231 plant species were recorded in 63 plots distributed within the study area, and this total number included 20 endemic species. Species richness was mainly affected by the type of management, soil attributes, altitude, and bioclimate. Pastoral value was strongly affected by nutrient availability and bioclimate. Our results suggest that the cover of endemic species increases with altitude. Finally, in Sardinian rangelands, a negative effect of grazing pressure on endemic species was observed.

Epilithic diatom assemblages and environmental quality of the Su Gologone karst spring (centraleastern Sardinia, Italy)

AbstractKarst springs are considered among the most vulnerable groundwater-dependent ecosystems. Despite their ecological value and importance as strategic water sources, Mediterranean karst springs are still poorly investigated. The aim of this study was to analyse the epilithic diatom assemblages and to test their usefulness as indicators of environmental quality on the Su Gologone spring (central-eastern Sardinia, Italy), a biotope of great natural value and a precious source of drinking water. A total of 89 diatom taxa were found with 25 new records for Sardinian running waters. Species richness, Shannon-Wiener and Pielou indices showed good biotic integrity. The dominant taxa were alkaliphilous, halophobous-oligohalobous exigent, xeno- oligosaprobic and characteristic of oligotrophic waters. The eutrophication/pollution index − diatom based (EPI-D) and the Navicula Nitzschia Surirella indices indicated respectively an excellent/good biological water quality and a low physical disturbance. However, the biological and chemical oxygen demand, and the microbiological variables (E. coli, fecal and total coliforms) revealed an organic contamination of the water, although moderate. The judgment provided by the EPI-D should be verified after updating of the index. In fact, 10 taxa found in this study are not currently considered by the EPI-D method.

Ethnopedology in the study of toponyms connected to the indigenous knowledge on soil resource.

In taking an integrated ethnopedological approach, this study aims to investigate the meaning of the distribution of the toponyms used in traditional and recent cartography of Sardinia (southern Italy). It is particularly, but not only, focused on those related to soil resources. Sardinia is particularly interesting in this respect, as its unique history, geography, and linguistic position makes it one of the Italian and Mediterranean regions with the greatest number of toponyms. This research investigated the toponyms belonging to an important sub-region of Sardinia, called Ogliastra (central-eastern Sardinia). The research was conducted through the following integrated approach: i) toponymy research and collection from different sources; ii) database creation and translation of toponyms from the Sardinian language (SL); iii) categorization of toponyms; and iv) graphical, statistical, and cartographic data processing. Distribution and diversity of toponyms were assessed using the compiled database, coupled with a geographical information system (GIS). Of around 7700 toponyms collected, 79% had already been reported in SL, while just 21% were in Italian. Of the toponyms in SL, 77% are of known meaning and 54% of these toponyms were characterized by a meaning directly and/or indirectly connected to specific environmental features. On the whole, morphology would appear to be the primary environmental factor able to explain the complex, articulated presence, distribution, and typology of the investigated toponyms. A least squares regression analysis of pedodiversity vs. topodiversity shows a very closed distribution, with an impressive high correlation index (R2 = 0.824). The principal factor analysis (PFA) shows that such a connection may be morphologically based, thereby confirming that pedodiversity and topodiversity are strongly linked each other. Overall, the research shows that an integrated ethnopedological approach, combining indigenous and scientific knowledge may be of great interest in order to mitigate the impressive phenomena of the indigenous knowledge lost.

Consanguinity and late fertility: spatial analysis reveals positive association patterns.

The role of consanguinity on human complex traits is an important and controversial issue. In this work we focused on the Sardinian population and examined the effect of consanguineous unions on late female fertility. During the last century the island has been characterized by a high incidence of marriages between relatives, favoured by socio economic conditions and geographical isolation, and by high fertility despite a widespread tendency to delay reproduction. Through spatial analysis techniques, we explored the geographical heterogeneity of consanguinity and late fertility, and identified in Central-Eastern Sardinia a common area with an excess of both traits, where the traits are positively associated. We found that their association did not significantly affect women's fertility in the area, despite the expected negative role of both traits. Intriguingly, this critical zone corresponds well to areas reported by previous studies as being peculiar for a high frequency of centenarians and for lower risk in pregnancy outcome. The proposed approach can be generally exploited to identify target populations on which socioeconomic, biodemographic and genetic data can be collected at the individual level, and deeper analyses carried out to disentangle the determinants of complex biological traits and to investigate their association.

Floristic Traits and Biogeographic Characterization of the Gennargentu Massif (Sardinia)

BACCHETTA, G., G. FENU, R. GUARINO, G. MANDIS, E. MATTANA, G. NIEDDU & C. SCUDU (2013). Floristic traits and biogeographic characterization of the Gennargentu massif (Sardinia). Candollea 68: 209-220. In English, English and French abstracts. A study on the vascular flora of the Gennargentu Massif (Central-Eastern Sardinia) is presented. According to our results, the flora consists of 948 taxa: 686 species, 249 subspecies, 10 varieties and 3 hybrids, belonging to 97 families and 427 genera. Three taxa are new findings for the flora of Italy and eight for that of Sardinia. Life form analysis revealed, in particular, dominance of 35.65% hemicryptophytes, 34.6% therophytes, 12.13% geophytes and 11.6% (nano)-phanerophytes. As concerns chorology, the Mediterranean element is largely prevailing (68.14%), mainly represented by circumMedit. (29.1%) and Euro-Medit. (23.07%). Endemics are 14.87% of the whole flora (141 taxa), with a large prevalence of Sardo-Corsican (39.01%) and Sardinian taxa (35.46%), i.e. 74.47% of the total. Due to the high number of taxa (9) of Gennargentu exclusive endemics and the geologic and geomorphologic peculiarities, it is here proposed a biogeographic classification for these territories serving to the identification of an auto nomous sector.

Thermal niche for in situ seed germination by Mediterranean mountain streams: model prediction and validation for Rhamnus persicifolia seeds.

Mediterranean mountain species face exacting ecological conditions of rainy, cold winters and arid, hot summers, which affect seed germination phenology. In this study, a soil heat sum model was used to predict field emergence of Rhamnus persicifolia, an endemic tree species living at the edge of mountain streams of central eastern Sardinia. Seeds were incubated in the light at a range of temperatures (10-25 and 25/10 °C) after different periods (up to 3 months) of cold stratification at 5 °C. Base temperatures (Tb), and thermal times for 50 % germination (θ50) were calculated. Seeds were also buried in the soil in two natural populations (Rio Correboi and Rio Olai), both underneath and outside the tree canopy, and exhumed at regular intervals. Soil temperatures were recorded using data loggers and soil heat sum (°Cd) was calculated on the basis of the estimated Tb and soil temperatures. Cold stratification released physiological dormancy (PD), increasing final germination and widening the range of germination temperatures, indicative of a Type 2 non-deep PD. Tb was reduced from 10·5 °C for non-stratified seeds to 2·7 °C for seeds cold stratified for 3 months. The best thermal time model was obtained by fitting probit germination against log °Cd. θ50 was 2·6 log °Cd for untreated seeds and 2·17-2·19 log °Cd for stratified seeds. When θ50 values were integrated with soil heat sum estimates, field emergence was predicted from March to April and confirmed through field observations. Tb and θ50 values facilitated model development of the thermal niche for in situ germination of R. persicifolia. These experimental approaches may be applied to model the natural regeneration patterns of other species growing on Mediterranean mountain waterways and of physiologically dormant species, with overwintering cold stratification requirement and spring germination.

<p><strong>A new species of <em>Aquilegia </em>(Ranunculaceae) from Sardinia (Italy)</strong></p>

The new species Aquilegia cremnophila (Ranunculaceae) from the Italian island of Sardinia is here described and illustrated. It occurs in shady rocky crevices, near the upper parts of Mt. Corrasi (Supramontes Region), where it is a member of chasmophilous communities. This species is morphologically, phenologically, ecologically and genetically well differentiated from the other Sardinian taxa, showing some relationships mainly with A. nugorensis, an endemic species of Central-Eastern Sardinia. Its conservation status is examined. A key of all taxa present in Sardinia is also provided.

Two new Typhloreicheia species from Sardinia and their biogeographical significance (Coleoptera, Carabidae, Scaritinae)

Typhloreicheia monacha sp. n. and Typhloreicheia ilianae sp. n. are described from two caves of Central-Eastern Sardinia (Nuoro province): the Bue Marino cave and the Nurra ‘e Pradu cave, respectively. Both caves are located in the part of the island where many highly specialised subterranean carabid beetles are localised. Typhloreicheia monacha is apparently related to two other species of the same area, i.e. Typhloreicheia onnisi Casale & Magrini, 2004 and Typhloreicheia elegans (Dodero, 1916); Typhloreicheia ilianae is closely related to Typhloreicheia henroti Jeannel, 1957, known from a cave near Dorgali. Relationships and diagnostic features among these taxa are discussed and illustrated, and a key for identification of the specialised subterranean Typhloreicheia species of Sardinia is provided. The hypothesis of adaptive radiation of Reicheiina species in Sardinia, recently proposed by the senior author of this contribution, is further elaborated in light of new data.

Genetic variability of the narrow endemic Rhamnus persicifolia Moris (Rhamnaceae) and its implications for conservation

Rhamnus persicifolia Moris is an endemic small tree belonging to the Rhamnus cathartica group, growing along mountainous streams of Central-Eastern Sardinia (Italy). ISSR markers were used to detect the genetic diversity within and among six populations representative of the species distribution range. In spite of the limited distribution of this endemic taxon, fairly high levels of genetic diversity were detected. Percentage of polymorphic bands (PPB), gene diversity ( H S and H T ) and Shannon information measure (Sh) were calculated both at population (PPB = 30.70%, H S = 0.1105, Sh = 0.1646) and at species level (PPB = 68.42%, H T = 0.2066, Sh = 0.3139). The existence of a spatial distribution of genetic diversity in R. persicifolia was revealed by a low gene flow, a fairly high level of genetic differentiation ( G ST = 0.4583) among populations and a positive correlation between genetic and geographic distances (Mantel test, r = 0.71, p = 0.016). The spatial genetic structure was also confirmed with BAPS analysis. Our results show that a certain level of isolation by distance and sex-ratio bias may explain the distribution of genetic diversity among populations. Conservation measures are suggested on the basis of the genetic diversity detected, by implementing an integrated in situ and ex situ conservation program for each population, in order to ensure effective protection for this endemic species. ► Rhamnus persicifolia an endemic tree growing in Sardinia (Italy) was studied. ► ISSR detected the genetic diversity within and among populations of the species. ► Quite high levels of genetic diversity were detected at both levels. ► A spatial genetic structure was detected with BAPS analysis. ► Measures are suggested for integrated in situ and ex situ conservation programs.

Osservazioni sulla rinnovazione naturale in boschi di leccio dell’Ogliastra (Sardegna) soggetti a pascolo

Abstract: This paper deals with the effects of grazing pressure in two Holm oak (Quercus ilex) stands in Ogliastra (central-eastern Sardinia, Italy), with particular reference to the interactions with the natural regeneration processes. There is a positive interaction (facilitation) between shrubs and seedlings of tree species, as observed in other similar studies carried out by the same authors in other areas of Sardinia. Rubus ulmifolius proved to be the most efficient shrub for the protection and growth of saplings; the other shrub species play a less marked facilitating role. Although the density of shrubs hosting Holm oak seedlings is fairly high, their age and small size confirm that the current grazing pressure is incompatible with any chance of growth of the saplings and success of the natural regeneration. The conservation of these stands must therefore rely on the rationalisation of human activities through the exploitation of a whole range of resources.

The Endemic Vascular Flora of Supramontes (Sardinia), a Priority Plant Conservation Area

FENU, G., E. MATTANA, A. CONGIU & G. BACCHETTA (2010). The endemic vascular flora of Supramontes (Sardinia), a priority plant conservation area. Candollea 65: 347–358. In English, English and French abstracts.The main aim of this work is to present a checklist of the endemic vascular flora of the Supramontes region (Central Eastern Sardinia) in order to classify this area in the Sardinian biogeographic subprovince and to better assess its conservation priorities. It is one of the most interesting regions of the Island and spreads for 335 km2 from the inland limestone massif to the Orosei gulf. This work was based on bibliographic and herbarium studies, integrated by several field surveys carried out from 2004 to 2009. In this study 138 endemic taxa, belonging to 98 genera and 42 families, have been found, with 92 of which being species, 40 subspecies, 5 varieties and 1 hybrid. The analysis of biologic and chorologic data highlighted the peculiarities of this territory. Due to the relatively high number of Supramontes exclusive endemics and to the geologic and geomorphologic peculiarities, it is here proposed a biogeographic classification for these territories and the identification of an autonomous biogeographic sector divided in two distinct subsectors. According to the recent conservation policies at local level, we propose the definition of micro hotspots for this sector, which hold ca. the 40% of the endemic flora of Sardinia, and the concept of nano hotspots for three narrows areas with an exceptional concentration of endemic species, which represent less than 1% of the whole sector surface and whose in situ protection may allow conserving of more than 80% of the vascular endemic flora of this sector.

Soil degradation by land use change in an agropastoral area in Sardinia (Italy)

In recent decades the clearing of Mediterranean maquis along with the creation of new pastures has been a major factor of land degradation in Sardinia (Italy). This was due to an inadequate implementation of agricultural policies. Consequently, tillage and water erosion intensified over a wide area. The present work assesses the impacts of land use change on soil properties in a representative area of central-eastern Sardinia. Paired forest and pasture sampling sites were selected in relation to present land use, land suitability, and land use history. Different soil properties were considered: physical (sand, silt, clay, soil thickness, bulk density, and penetration resistance), chemical (pH, OC, N, C/N, Ca, Mg, Na, K, CEC, and BS), biological (BQI), and micromorphological (microporosity and microstructure). The comparison of forest and pasture soils showed a significant soil loss (in terms of soil thickness, −22%), and a clear decrease in organic carbon storage (−64% on average). An increase in bulk density (+ 44%) and a change in microporosity and its vertical distribution were also observed, respectively by field measurements and micromorphological quantification on digital images.

Comparative germination ecology of the endemic Centranthus amazonum (Valerianaceae) and its widespread congener Centranthus ruber

Abstract Centranthus amazonum Fridl. & A. Raynal (Valerianaceae) is a critically endangered narrow endemic to Central–Eastern Sardinia (Italy), where it occurs in rocky habitats. In the present study, the germination ecology of this species was investigated and compared with the relatively widespread species Centranthus ruber (L.) DC. subsp. ruber. In particular, the effects of a range of constant temperatures (5–25°C) and two alternating temperature regimes (25/10 and 30/15°C) on seed germination were analyzed. For the two species, cardinal temperatures were determined as the reciprocal of time to 50% germination (t50). In addition, seed persistence in the soil was assessed by experimental seed burials. Seeds of both species were non‐dormant; however, C. amazonum produced more empty seeds and germination was slower and reached lower final percentages than C. ruber. Moreover, seed and seedling mass of C. ruber were higher than for C. amazonum and the lack of a persistent soil seed bank detected for C. amazonum increases vulnerability to extinction for this species. The present study provides new data on the germination ecology of the previously unstudied C. amazonum that may explain the rarity of this species when compared with the commonness of C. ruber.

Effects of temperature, light and pre-chilling on germination of Rhamnus persicifolia, an endemic tree species of Sardinia (Italy)

Rhamnus persicifolia is an endemic small tree or shrub belonging to the R. cathartica group. It grows along mountainous waterways of the Central-Eastern Sardinia (Italy). The purpose of this study was to report the effects of temperature, light and pre-chilling on germination of R. persicifolia seeds. The applied treatments included a range of constant temperatures (5-30°C) and two alternating temperature regimes (15/5 and 25/10°C), with two photoperiods (8 h light / day and darkness). In addition, the most effective germination temperature (25°C) was repeated including a pre-chilling period (5°C for 3 months). R. persicifolia reached maximum germination percentages (> 70%) at warm temperatures (≥ 20°C), with no differences between constant and alternating regimes and no response to light. While the pre-chilling period did not increase germination percentage it had a positive effect on germination rate, reducing T50 by more than 50%. These studies provide new information on the seed biology of this endemic species and enable ex situ seed germination, which may prove useful for habitat restoration activities.

Effects of land use and landscape on spatial distribution and morphological features of gullies in an agropastoral area in Sardinia (Italy)

According to the United Nations Convention to Combat Desertification (UNCCD), soil erosion is one of the main causes of desertification in the Northern Mediterranean. Recently, the role of channelled erosion in sediment delivery has been underlined by several studies. The aim of this paper is to describe a simplified experimental methodology settled up for studying the relationships between gully erosion and land use. The experimental site, which is wide about 720 ha, is located in a hilly area threatened by desertification in Central Eastern Sardinia (Italy). This area is characterised by irregular morphology with steep slopes, where agropastoral activities, particularly tillage with heavy machinery and overgrazing, are causing severe soil erosion and compromising agricultural productivity. Previous studies carried out in the same area highlighted the need to quantify and monitor soil erosion in order to outline management guidelines for farmers. In this study, an integrated methodology that uses aerial photographs and field surveys was applied to inventory the gullies of the area. The degree of activity and morphological characteristics of gullies were assessed in the field by measuring the position and shape of gully heads, and their width and depth. Total gully volume was also estimated. Relationships among distribution, density and morphological characteristics of gullies, and geomorphological features, land use and land use historical dynamics of the area have been studied. The results show the very significant impact of agricultural activities on gully activity and density.