Conservation and management issues of Prespa National Park

The present article describes the human activities inthe area and their changes and trends, given that thecontemporary nature conservation key issues areclosely related to past and present socio-economic andcultural conditions, both within Prespa itself andoutside of it. The liberation of Prespa, a remote andrather socially isolated borderline area, from Ottoman occupation took place in 1912–13. Recentevents in its environmental history have been forestclearings and human depopulation in the Civil War(1944–49), irrigation system construction in the1960s, its discovery by ornithologists in the late1960s, the high emigration rates of 1960–1980, itsdesignation as a National Park in 1974, thedestructive development works of 1984–86 afterGreeces entry to the EEC and the conversion to intensivebean cultivation in the mid 1980s.The human population of ca 7000 at the start of thiscentury suffered an almost 80% decrease after theCivil War. A resettlement in the mid 1950s increasedthe population by 40% but in the 1970s emigrationreduced it to its previous size of around 1500, stillits present size. The extensive and diverse farmingsystems of previous centuries changed gradually afterthe construction of an irrigation network in the1960s, which twenty years later and along withinternational changes in production and economypatterns, made possible the present day domination ofa bean monoculture within irrigated croplands. Thiswas accompanied by increased energy inputs,mechanisation and the use of chemicals.Intensification of agriculture brought increasedincomes which attracted also livestock keepers,resulting in a 56% decrease in numbers of livestockin 1964–1993. Cattle are presently kept for meatproduction only. They graze on the mountains, and nolonger in the meadows around the lakeshore. A localshorthorn breed accounting for 93% of all cattle in1963 declined to less than 18% in 1993. Fishing aimedmainly at carp and Prespa bleak, continues today as inthe past to be a source of supplementary income.Eighty-six per cent of the – mainly oak and beech –forests are State owned and the rest belong to localmunicipalities. The forest area has not changedessentially in the last 40 years, but forest roadshave expanded. Forests provide mainly fuelwood forlocal needs and small quantities of industrial timber.No specific management is conducted to safeguard theconservation values of the forest, the majority ofwhich consists of even aged coppiced stands withlimited value for wildlife. Manufacturing never playedan important role for the economy of the area. Tourismhas increased in the last 20 years, concentratedmainly in summer and spring. Accommodation in thevillages is not yet satisfactory though it hasimproved enormously in recent years. The NationalParks infrastructure for visitors remains poor.Tourist pressure generally is not yet that high toimpact drastically the social and environmentalfabric. In places, hunting, angling and poaching cannegatively affect the target species. The constructionof the irrigation network in the eastern part of LakeMikri Prespa was the most important change to thelandscape and the habitats of Prespa the last 30years. It resulted in the embankment of free-flowingstreams, drainage of wet meadows and dramaticreduction of trees and hedges. In the last 15 years,the reedbeds, no longer burnt or mowed and assisted byincreased nutrient loadings from agricultural runoff,have expanded landward to occupy formerly open,periodically flooded, areas. The above changes inhabitats and land use have brought an impoverishmentof biodiversity which can be seen in the exterminationor the decrease in the numbers of certain plant andbird species.The problems preventing a better management of theNational Park and the perpetuation of its values areinappropriate legislation, the poor degree ofcoordination of the public services, the lack of botha specific National Park Service in Greece and amanagement authority for the Park and the hostileattitude of local people due to their limitedinformation and involvement. The scenic beauty, thewetlands and a number of rare habitats, the diversityof habitats, flora and fauna, the endemic life forms,the rare mammals and the colonial waterbirds, thelocal architecture and the cultural expressions suchas the Byzantine monuments, are the values of Prespathat must be preserved as a whole. The initialconservation efforts aimed at preserving biodiversitybut later it became apparent that not only are humansan inseparable part of the whole, but additionally,several of their extensive activities have contributedsubstantially to the rich biodiversity of the area.Through the prerequisites of keeping a balance betweenprimary and tertiary sector activities and ofrevitalizing the social fabric, the following are thekey management and conservation issues of today: anunequivocal agreement on the values to be preservedand their limits; the formation of a managementauthority; a new realistic protection and land usezoning; the diversification and extensification of allfarming activities; the restoration of the wet meadowhabitats; the ensuring of a high water level and agood water quality for both lakes through tri-lateralcooperation between Greece, Albania and FYROM; and theestablishment of a permanent environmental monitoringscheme.     

Polycystin-1 downregulation induces ERK-dependent mTOR pathway activation in a cellular model of psoriasis

Psoriatic plaques tend to localize to the knees and elbows, areas that are particularly subject to mechanical stress resulting from bending and friction. Moreover, plaques often develop at sites of mechanical trauma or injury (Koebner phenomenon). Nevertheless, mechanotransduction has never been linked to psoriasis. Polycystins (polycystin-1, PC1; polycystin-2, PC2) are mechanosensitive molecules that function as key regulators of cellular mechanosensitivity and mechanotransduction. The aim of this in vitro study was to investigate the role of polycystins in the development of psoriasis. We showed that PC1 knockdown in HaCaT cells led to an elevated mRNA expression of psoriasis-related biomarkers Ki-67, IL-6, TNF-α, VEGF and Bcl-2, while PC1 functional inhibition was accompanied by increased cell proliferation and migration of HaCaT cells. In addition, PC1 knockdown via siRNA in HaCaT cells was followed by activation of critical molecules of the mTOR and MAPK pathways and this mTOR pathway activation was ERK-dependent. Furthermore, loss of PC1 protein expression and elevated levels of activated mTOR substrates were also observed in human samples of psoriatic plaques. Overall, our study suggests that the PC1/ERK/mTOR signaling axis represents a novel potential mechanism in psoriasis pathogenesis.     

Fish and fisheries of the Prespa lakes

Twenty-three taxa of fish have been identified fromthe Prespa lakes. Eleven of these have been introducedor translocated, and 7 of the remaining 12 are endemicto the Prespa lakes. This high proportion of endemismrequires confirmation because the systematic positionof several of the species and subspecies remainsuncertain. The absence of a predatory fish in MikriPrespa, the occurrence of trout in Megali Prespa, thepresence of eels in both lakes and the occurrence ofmany rheophilous fish species typifies the fishcommunities of these two lakes. Monitoring of the fishpopulation in Mikri Prespa, from 1984 to 1994, showedapparent stability or a slight increase in catchesduring this period. Not all the introduced specieshave been able to establish populations and theirimpact on the indigenous populations is yet to bedefined. A spectacular re-establishment of the carppopulation, following the crash of the stock of thisspecies in the 1970s–1980s, was recorded in the springof 1991. The past and present situation of thefisheries in lakes Mikri and Megali Prespa isdescribed, and their productivity and yields areanalysed. Particular attention is given to atraditional fishing method unique to the Presparegion: pelaizia fishing. The factors involved inthe temporal trends in the fisheries are identifiedand analysed. Recommendations for the management ofthe fish populations and the fisheries are proposed,so that the sustainability of this resource and thesurvival of the endemic fish species can beensured.     

Spatially correlated environmental factors drive synchronisation in populations of the Dalmatian Pelican

Spatial synchrony in population dynamics has been documented recently across a range of taxa, and a number of hypotheses about the mechanisms driving spatial synchrony and the consequences of this phenomenon for the persistence of populations have emerged. Spatial environmental covariance is one of the principal factors influencing this synchrony on a large scale. However, most studies focus on population abundances, and little evidence exists on the spatial synchrony of demographic parameters. We used a 15-year dataset from two populations of a vulnerable bird species, the Dalmatian Pelican (Pelecanus crispus), to identify local and global environmental factors that cause population synchrony. We show that survival rates were temporally synchronised between the studied populations and that a large part (>50 % for both populations) of this covariation was driven by local environmental conditions. Several components of the North Atlantic Oscillation index were correlated with local climatic conditions, but not all of these components can be used as informative proxies for future variation in survival. We also present evidence that an individual's future survival can be strongly influenced by the conditions occurring during the early period of its life. Environmental factors such as water level and food availability had similar influences on breeding success and juvenile survival. Juvenile survival was lower during dry years and years of low food availability. This finding indicated that intra-specific competition may act as a limiting factor for species demography, especially in large populations. Estimating the strength of synchrony is important and should be considered in population and metapopulation analyses and in relationship to conservation measures.