Many have asserted that Sacred Natural Sites (SNS) play an important role in nature protection but few have assessed their conservation effectiveness for different taxa. We studied sacred groves in Epirus, NW Greece, where a large number of such SNS have been identified. Based on historical, ethnographic and ecological criteria, we selected eight of these groves and matching control sites and in them we studied fungi, lichens, herbaceous plants, woody plants, nematodes, insects, bats and passerine birds. Our results reveal that the contribution of SNS to species conservation is nuanced by taxon, vegetation type and management history. We found that the sacred groves have a small conservation advantage over the corresponding control sites. More specifically, there are more distinct sets of organisms among sacred groves than among control sites, and overall biodiversity, diversity per taxonomic group, and numbers of species from the European SCI list (Species of Community Interest) are all marginally higher in them. Conservationists regard the often small size of SNS as a factor limiting their conservation value. The sizes of SNS around the globe vary greatly, from a few square meters to millions of hectares. Given that those surveyed by us (ranging from 5 to 116 ha) are at the lower end of this spectrum, the small conservation advantage that we testified becomes important. Our results provide clear evidence that even small-size SNS have considerable conservation relevance; they would contribute most to species conservation if incorporated in networks.

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In this paper, we present a novel approach for using ecological heterogeneity in reserve design. We measured five ecological heterogeneity indices (EHI) and we used a database of six biological groups (woody plants, orchids, orthopterans, aquatic and terrestrial herpetofauna and passerine birds) across 30 sites in a Mediterranean reserve (Greece). We found that all the five EHI were significantly related to the overall species richness and to the species richness of woody plants and birds. Two indices, measuring vertical vegetation complexity (1/D) and horizontal heterogeneity of landcover types (SIDI) in terms of Simpson's index, predicted well overall species richness and had significantly higher values inside the complementary reserve networks designed after five of the six biological groups. We compared five methods of forming reserve networks. The Electronic supplementary material The online version of this article (doi:10.1007/s10531-010-9788-y) contains supplementary material, which is available to authorized users. method of ecological heterogeneity (selecting those sites with the greatest 1/D and then SIDI) was less efficient (non-significantly) than the species-based methods (scoring and complementary networks) but significantly more efficient than the random method (randomly selected network). We also found that the method of complementary ecological heterogeneity (selecting those sites where each EHI had its maximum value) was not that efficient, as it did not differ significantly from the random method. These results underline the potential of the ecological heterogeneity method as an alternative tool in reserve design.

Earth observation data can provide important information for tree species diversity mapping and monitoring. The relatively recent advances in remote sensing data characteristics and processing systems elevate the potential of satellite imagery for providing accurate, timely, consistent, and robust spatially explicit estimates of tree species diversity over forest ecosystems. This study was conducted in Northern Pindos National Park, the largest terrestrial park in Greece and aimed to assess the potential of four satellite sensors with different instrumental characteristics, for the estimation of tree diversity. Through field measurements, we originally quantified two diversity indices, namely the Shannon diversity index (H’) and Simpson’s diversity (D1). Random forest regression models were developed for associating remotely sensed spectral signal with tree species diversity within the area. The models generated from the use of the WorldView-2 image were the most accurate with a coefficient of determination of up to 0.44 for H’ and 0.37 for D1. The Sentinel-2 -based models of tree species diversity performed slightly worse, but were better than the Landsat-8 and RapidEye models. The coefficient of variation quantifying internal variability of spectral values within each plot provided little or no usage for improving the modelling accuracy. Our results suggest that very-high-spatial-resolution imagery provides the most important information for the assessment of tree species diversity in heterogeneous Mediterranean ecosystems.

Differences in needle traits of coniferous tree species are considered as the combined result of direct environmental pressure and specific genetic adaptations. In this study, diversity and differentiation within and among four Abies cephalonica subpopulations of a marginal population on Mt. Parnitha-Greece, were estimated using needle morphological traits and gene markers. We tested the connection of morphological variability patterns of light and shade needles with possible adaptation strategies and genetic diversity. Six morphological characteristics were used for the description of both light and shade needles at 100 trees, describing needle size and shape, stomatal density and needle position on the twigs. Additionally, six RAPD and three ISSR markers were applied on DNA from the same trees. Light needles were significantly different than shade needles, in all traits measured, apparently following a different light harvesting strategy. All four subpopulations exhibited high genetic diversity and the differentiation among them was relatively low. Differences among populations in light needles seemed to depend on light exposure and aspect. In shade needles, the four subpopulations seemed to deviate stronger from each other and express a rather geographic pattern, similarly to the genetic markers. Two of the subpopulations studied were lost during a wildfire, two years after sampling. Although the subpopulations burnt were most diverse and most differentiated, we expect a large part of the total genetic diversity of the burnt trees to still exist in the surviving subpopulations, since gene flow must have been effective in keeping all subpopulations connected.