TY - JOUR T1 - Why scale matters? Life connections in the littoral of remote mountain lakes JF - bioRxiv DO - 10.1101/034553 SP - 034553 AU - Dragos G. Zaharescu AU - Carmen I. Burghelea AU - Peter S. Hooda AU - Antonio Palanca-Soler Y1 - 2015/01/01 UR - http://biorxiv.org/content/early/2015/12/16/034553.abstract N2 - In low nutrient alpine lakes, littoral surfaces are the most productive part of the ecosystem, and they are biodiversity hotspots. It is not entirely known how the nature and properties of lake surrounding catchments, their ecological structure and larger landscape factors work together at different scales to shape the structure and functioning of littoral ecosystems.A total of 114 high altitude lakes and ponds in the central Pyrenees were surveyed to assess the relative control of catchment properties at a variety of scales on littoral zoobenthic communities. At each location benthic invertebrate composition was recorded together with geolocation (altitude, latitude and longitude), composite factors representing hydrodynamics, geo-morphology and topography, riparian vegetation composition, presence of vertebrate predators (trout and frogs), and water pH and conductivity.A two-step fuzzy set ordination (FSO)-multidimensional FSO (MFSO) model integrating benthic biota and environmental variables revealed that at geographic scale, longitude gradient surpassed altitude in its influence on littoral ecosystem, reflecting a transition between Atlantic and Mediteranean biogeographic regions. Within each catchment, topography (through its control of catchment type, shore and catchment snow coverage, and connectivity with other lakes) was the main driver of taxa composition, while hydrodynamics (waterbody size, type and inflow/outflow volumes) was secondary, and strongly covaried with the former. Locally, riparian plant composition was tightly connected with littoral invertebrate community structure, richness and morphotype diversity. These variables work directly and indirectly by creating habitats (for both, aquatic and terrestrial invertebrate stages), control the water renewal and nutrient input. They together sustained three ecologically tolerant associations adapted to different environments where the lakes are set.In-lake predation, water conductivity and pH (broad measures of total dissolved ions/nutrients and their bioavailability) had no major influence on benthic communities, being potentially connected to their naturally high variability.The findings imply a strong dependence of altitude lake littoral ecosystems to surrounding landscape processes at scales beyond the local environment, which underpins their role as sensors of local and large-scale environmental change. The work also provides exhaustive data on processes characterizing relatively pristine sites, which can help evaluate how major climate/environmental changes can affect their environments. ER -