Temperature preferences and small-scale distribution patterns of four Dermatocarpon taxa in the catchment areas of two Bulgarian rivers were analyzed. Taxa with an overall alpine or arctic-alpine distribution were restricted to microhabitats with the lowest water and rock surface temperatures. A trend for increasing Dermatocarpon rivulorum thallus diameter and colony size (aggregates of thalli) with decreasing temperature was identified. Data on pH and conductivity of the water for the study sites are provided for all taxa. Dermatocarpon arnoldianum is reported for the first time from Bulgaria, confirmed by ITS sequence data, and its known range extends to South-East Europe. All previous records of D. rivulorum from Bulgaria were based on misidentified specimens of D. arnoldianum. Freshwater taxa of Dermatocarpon are proposed as a tool for monitoring the biological effects of temperature changes due to global climate change. Thallus and colony size are recommended as additional features for monitoring populations of threatened Dermatocarpon species.

Late glacial scenarios of ice retreat and biogeography databases constrain the dispersal routes of obligate freshwater fishes into Atlantic Canada and Maine. Evidence indicates glacial ice covered the present-day mainland and offshore islands at 18,000 14C yr before present. Possible refugia for extirpated freshwater fishes were the exposed outer edge of the Grand Banks (east), exposed Georges Bank (south-Atlantic Refugium), and the Mississippi Refugium in the west. It is improbable that the region was recolonized from the offshore refugia. Rather, fishes recolonized from the east via the upper St. Lawrence River valley into the upper Saint John River, Maine (Lake Madawaska) from 11,000 to 12,000 14C yr BP. The short period of entry resulted in the low diversity of obligate freshwater species in the region. Lake Madawaska was breached and dispersal continued into the remainder of the region after 8000 14C yr BP. By 6000 14C yr BP, access routes to the east along low-lying coastal zones were blocked by rising sea levels, which isolated Prince Edward Island, Cape Breton Island, and most probably Nova Scotia. Natural dispersal across the region appeared complete by this time.

Mediterranean temporary ponds (MTPs) are highly distinctive habitats with intermittent and unstable environmental conditions,inhabited by several rare and endemic plant and animal species. Temporary pond ecosystems have been classified asendangered all over the world; nevertheless, they are disappearing at a high rate, especially in the Mediterranean region. MTPsare a priority habitat under the European Union Habitats Directive and thus appropriate management and conservation effortsshould be applied. Further research is needed in order to better understand the environmental characteristics and ecology of thishabitat which is not always the case in many countries. In this study a range of environmental data were collected from the GreekMTP habitat sites including the altitude, the geology, the representativity, the ecological status and other biological data aimingto assess the environmental status of all known Greek MTPs. Statistical analysis were performed and thematic maps were createdusing a Geographical Information System (GIS). Greek MTP’s were classified according to their characteristics and habitatpressures were identified and further analysed. A comparison between the present environmental status of the MTPs in Greecewith the MTPs in other Mediterranean countries was undertaken and relevant conservation and management measures were proposed.The outcome of this study was that a significant percentage of the MTP habitat sites in Greece are at risk mainly due tohuman activities, such as agricultural pollution, expansion of cropland and water resources over-exploitation. It was concludedthat immediate restoration and conservation actions should be taken so as to prevent further ecological degradation.

The lichen flora of freshwater habitats in the Italian Alps is reviewed: 20 genera and 43 species are known, of which crustoselichens with sexual reproduction prevail. Freshwater lichen richness is highest near the treeline on siliceous substrata in exposedand well-lit sites. The importance of several ecological factors on freshwater lichen distribution and ecology is discussed.