Suchergebnisse

Abstract. Historical fire records and meteorological observations spanning over one century (1894–2010) were assembled in a database to collect long-term fire and weather data in Greece. Positive/negative events of fire occurrence on an annual basis were considered as the years where the annual values of the examined parameters were above (positive values) or below (negative values) the 95% confidence limits around the trend line of the corresponding parameter. To analyse the association of positive/negative events of fire occurrence with meteorological extremes, we proceeded with a cross-tabulation analysis based on a Monte Carlo randomization. Positive/negative values of total annual precipitation were randomly associated with the corresponding values of burned areas, and significant associations were observed for seasonal precipitation totals (spring and fire season). Fire season precipitation is the dominant factor coinciding with negative values of area burned, while years with high spring precipitation coincide with years with large areas burned. These results demonstrate the dual role of precipitation in controlling a fire's extent through fuel build-up and dryness. Additionally, there is a clear outperformance of precipitation-related variables compared with temperature-related weather revealing that, at least in Greece, total area burned at the national scale is controlled by precipitation totals rather than air temperature. This analysis improves our understanding of the underlying mechanisms of fire regimes and provides valuable information concerning the development of models relating fire activity to weather parameters, which are essential when facing a changing climate that may be associated with shifts in various aspects of the typical fire regimes of ecosystems. Our results may allow fire managers to more easily incorporate the effect of extreme weather conditions into long-term planning strategies. They contribute to the exploration of fire–climate relationships and may become more important if climate change scenarios are used to predict the occurrence of future extreme weather taking into consideration that climate change is discussed on the basis of changes of extremes rather than changes in means.

One of the core European Union environmental policies is the creation and monitoring of the Natura 2000 network of protected areas. This network has been explicitly established for the preservation of conservation priority habitat types and species. Still the concept of habitat is a key concept for ecologists that remains ill defined and is notoriously hard to quantify and measure. Several classification schemes have been put forward, but their relative strengths and weaknesses remain less well examined. In this study we analyzed 8 different Natura 2000 sites (3 Greek, 2 Italian, 2 Portuguese, 1 British). Our study sites reflect a variety of ecosystems, most of them are Mediterranean (7 of the 8) and most of them are wetlands (6 of the 8). In each site, we classified habitats according to 4 different classification schemes (Annex I of the Habitats Directive, Corine Biotopes, EUNIS and General Habitat categories). Also, we used three other widely used land cover classification schemes (namely Corine Land Cover, FAO Land Cover Classification System and IGBP DIS scheme). We found that the different schemes produced considerably different values of landscape diversity leading even to different ranking of the sites according to their diversity. Furthermore, when comparing the landscape composition among sites according to the different schemes, they led to different inferences. Our results imply that the classification scheme used for estimating habitat composition plays an important role for the monitoring of protected areas, perhaps more important than previously assumed.

One of the core European Union environmental policies is the creation and monitoring of the Natura 2000 network of protected areas. This network has been explicitly established for the preservation of conservation priority habitat types and species. Still the concept of habitat is a key concept for ecologists that remains ill defined and is notoriously hard to quantify and measure. Several classification schemes have been put forward, but their relative strengths and weaknesses remain less well examined. In this study we analyzed 8 different Natura 2000 sites (3 Greek, 2 Italian, 2 Portuguese, 1 British). Our study sites reflect a variety of ecosystems, most of them are Mediterranean (7 of the 8) and most of them are wetlands (6 of the 8). In each site, we classified habitats according to 4 different classification schemes (Annex I of the Habitats Directive, Corine Biotopes, EUNIS and General Habitat categories). Also, we used three other widely used land cover classification schemes (namely Corine Land Cover, FAO Land Cover Classification System and IGBP DIS scheme). We found that the different schemes produced considerably different values of landscape diversity leading even to different ranking of the sites according to their diversity. Furthermore, when comparing the landscape composition among sites according to the different schemes, they led to different inferences. Our results imply that the classification scheme used for estimating habitat composition plays an important role for the monitoring of protected areas, perhaps more important than previously assumed.

Worldwide, there is a well-documented crisis for bees and other pollinators which represent a fundamental biotic capital for wild life conservation, ecosystem function, and crop production. Among all pollinators of the world, bees (Hymenoptera: Apoidea) constitute the major group in species number and importance, followed by hover flies (Diptera: Syrphidae). The Aegean constitutes one of the world's hotspots for wild bee and other pollinator diversity including flies (mainly hover flies and bee flies), beetles, and butterflies. Despite this advantage, our present knowledge on Greek pollinators is poor, due to a lack of focused and systematic research, absence of relevant taxonomic keys, and a general lack of taxonomic experts in the country. As a result, assessments of pollinator loss cannot be carried out and the causes for the potential pollinator loss in the country remain unknown. Consequently, the desperately needed National Red Data list for pollinators cannot be compiled. This new research (2012–2015) aims to contribute to the knowledge of the pollinator diversity in Greece, the threats pollinators face, as well as the impacts these threats may have on pollination services. The research is conducted in the Aegean archipelago on >20 islands and several mainland sites in Greece and Turkey. Prime goals are: i. the assessment of bee and hover fly diversity (species, genetic); ii. their pollination services; and iii. the effects of climate change, grazing, intensive bee-keeping, fires, electromagnetic radiation on bee diversity and ecology, as well as on plant–pollinator networks. At the same time, this research contributes to the taxonomic capital in Greece and the Eastern Mediterranean, focusing on the creation of the first identification keys for pollinators, the training of new scientists, as well as the enrichment and further development of the Melissotheque of the Aegean, a permanent reference collection of insect pollinators established at the University of the Aegean. ; En todo el mundo hay una crisis bien documentada para las abejas y otros polinizadores los cuales representan un capital biótico fundamental para la conservación de la vida silvestre, la función de los ecosistemas, y la producción de cultivos. Entre todos los polinizadores del mundo, las abejas (Hymenoptera: Apoidea) constituyen el grupo principal en cuanto al número de especies y su importancia, seguido por los sírfidos (Diptera: Syrphidae). El Egeo constituye uno de los puntos importantes de diversidad de abejas silvestres y otros polinizadores del mundo, incluyendo moscas (principalmente sírfidos y bombílidos), escarabajos y mariposas. A pesar de esta ventaja, los conocimientos actuales sobre los polinizadores griegos son reducidos, debido a la falta de una investigación focalizada y sistemática, la ausencia de claves taxonómicas pertinentes, y una falta general de expertos en taxonomía en el país. Como resultado, no se pueden llevar a cabo evaluaciones de la pérdida de polinizadores y las causas de la pérdida potencial de polinizadores en el país siguen siendo desconocidas. En consecuencia, la imperiosamente necesitaba Lista Roja de datos para polinizadores no se puede compilar. Esta nueva investigación (2012-2015) tiene como objetivo contribuir al conocimiento de la diversidad de polinizadores en Grecia, enfrentarse a las amenazas para los polinizadores, así como investigar el impacto que estas amenazas pueden tener sobre los servicios de polinización. La investigación se llevará a cabo en el archipiélago del mar Egeo en más de 20 islas y en varios sitios del continente en Grecia y Turquía. Los principales objetivos son: i. la evaluación de la diversidad de abejas y sírfidos (especies, genética); ii. sus servicios de polinización, y iii. los efectos del cambio climático, el pastoreo, la apicultura intensiva, los incendios y las radiaciones electromagnéticas sobre la diversidad de abejas y la ecología, así como en las redes planta-polinizador. Al mismo tiempo, esta investigación contribuirá a la taxonomía en Grecia y el Mediterráneo Oriental, centrándose en primer lugar en la creación de las claves de identificación para polinizadores, la formación de nuevos científicos, así como el enriquecimiento y el desarrollo de la Melisoteca del Egeo, una colección de referencia permanente de los insectos polinizadores establecidos en la Universidad del Egeo. ; This research is co-financed by the European Union (European Social Fund—ESF) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) - Research Funding Program: Thales -Investing in knowledge society through the European Social Fund.