Temporal and inter habitat variations of substratum, vegetation and substratum macroinvertebrates attributes across coastal wetland systems, North East Aegean, Greece

Using five coastal wetland systems across Kalloni bay, Lesvos Island, NE Aegean, we investigated: (I) the interaction between spatial units (land, wetland, sea) and seasons (spring, autumn) of substratum physicochemical attributes, vegetation composition and aerial cover, and substratum macroinvertebrates distribution and abundance and (II) the relative importance of substratum attributes in explaining temporal and inter habitat variations in vegetation and substratum macroinvertebrates distributions to elucidate the functional role of these coastal wetlands in the landscape. Electrical conductivity, percent organic matter and bulk density of substratum showed the most pronounced differences among spatial units, between seasons, and among spatial units x seasons interaction, respectively. Comparison of C:N and N:P ratios among spatial units and between seasons indicated that, in general, nitrogen and phosphorus appear to be limiting factors at the sea and the land unit, respectively. It is likely that these coastal wetlands function as transformers of chemical elements while P limits primary production. Significant substratum physicochemical attributes explained 23.4 and 14.7% of plants distribution in spring (percent organic matter, total phosphorus concentration, electrical conductivity) and autumn (electrical conductivity, pH), respectively, while significant substratum variables explained 46.1 and 73.3% of macroinvertebrates distribution in spring (percent organic matter) and autumn (total phosphorus concentration, electrical conductivity, percent organic matter), respectively

Ecological Processes and Contemporary Coral Reef Management

Top-down controls of complex foodwebs maintain the balance among the critical groups of corals, algae, and herbivores, thus allowing the persistence of corals reefs as three-dimensional, biogenic structures with high biodiversity, heterogeneity, resistance, resilience and connectivity, and the delivery of essential goods and services to societies. On contemporary reefs world-wide, however, top-down controls have been weakened due to reduction in herbivory levels (overfishing or disease outbreak) while bottom-up controls have increased due to water quality degradation (increase in sediment and nutrient load) and climate forcing (seawater warming and acidification) leading to algal-dominated alternate benthic states of coral reefs, which are indicative of a trajectory towards ecological extinction. Management to reverse common trajectories of degradation for coral reefs necessitates a shift from optimization in marine resource use and conservation towards building socio-economic resilience into coral reef systems while attending to the most manageable human impacts (fishing and water quality) and the global-scale causes (climate change)

Physicochemical characterization of the shallow mixing zone of two estuaries, Lesvos Island, NE Aegean, Greece

We assessed the physicochemical status of the mixing zone along two shallow estuaries within a Natura 2000 site, NE Greece, in order to establish a baseline and evaluate their trophic state. Distribution patterns of dissolved oxygen and chlorophyll a of water and of chlorophyll a, total phosphorus, and percent organic matter of sediment along the mixing zone of the studied estuaries during spring 2005 indicated oligotrophic conditions in autotrophic estuaries. In both estuarine systems, chlorophyll a concentration of water did not correlate with chlorophyll a of sediment indicating that different processes may control primary production in waters and sediments. Nevertheless, primary production in water was linked to phosphorus pool in sediment

Integrating Landscape Ecology and Geoinformatics to Decipher Landscape Dynamics for Regional Planning

We used remote sensing and GIS in conjunction with multivariate statistical methods to: (i) quantify landscape composition (land cover types) and configuration (patch density, diversity, fractal dimension, contagion) for five coastal watersheds of Kalloni gulf, Lesvos Island, Greece, in 1945, 1960, 1971, 1990 and 2002/2003, (ii) evaluate the relative importance of physical (slope, geologic substrate, stream order) and human (road network, population density) variables on landscape composition and configuration, and (iii) characterize processes that led to land cover changes through land cover transitions between these five successive periods in time. Distributions of land cover types did not differ among the five time periods at the five watersheds studied because the largest cumulative changes between 1945 and 2002/2003 did not take place at dominant land cover types. Landscape composition related primarily to the physical attributes of the landscape. Nevertheless, increase in population density and the road network were found to increase heterogeneity of the landscape mosaic (patchiness), complexity of patch shape (fractal dimension), and patch disaggregation (contagion). Increase in road network was also found to increase landscape diversity due to the creation of new patches. The main processes involved in land cover changes were plough-land abandonment and ecological succession. Landscape dynamics during the last 50 years corroborate the ecotouristic-agrotouristic model for regional development to reverse trends in agricultural land abandonment and human population decline and when combined with hypothetical regulatory approaches could predict how this landscape could develop in the future, thus, providing a valuable tool to regional planning