Hydrological change constraints on management success

REFRESH addresses the effects of climate-driven low flows and droughts on management success in rivers, on structure and functioning of river ecosystems, and on changes in river biodiversity. The focus is on low flows and droughts in relation to completeness and naturalness of in-stream habitats and the construction of riparian buffer strips/floodplain wetlands to establish water retention along Atlantic, small-sized lowland streams. In such streams, periods of low flow and droughts will increase and extreme summer floods can wash away communities. Indicators reflecting key hydrological conditions will be studied using controlled field/mesocosm experiments differing in intensity and periodicity of low flow. Algae, macroinvertebrates (in particular, oxygen sensitive groups) and macrophytes will be used as biological effect parameters, and a number of ecosystem and physico-chemical parameters will be monitored continuously

Left: Experimental stream site, La Tordera, Spain (Photo: Eugenia Marti)

 

Lake_Level_Change_TurkeyFor lakes REFRESH focuses on the direct and indirect (e.g. change in salinity) effects of water level change at low and high TP concentration on structure, function and metabolism.

We will:

  1. conduct innovative joint field experiments in six shallow lakes distributed along an eastern latitude gradient in Europe (from Sweden to Turkey);
  2. use these data and existing monitoring data to analyse how changes in water level (salinity) and nutrients will affect trophic structure, function and metabolisms and the benthic-pelagic coupling in lakes;
  3. develop key ecological and functional response parameters and indicators; and
  4. provide the scientific basis for adaptive lake management to counteract the effects of changes in water level (salinity).

We will also analyse existing (long-term) data series from contemporary and palaeoecological studies of freshwater, brackish and saline lakes along climatic gradients in Europe. Targeted additional field sampling will be made to fill in gaps and analyses of sediment cores will be undertaken to reconstruct changes in salinity, nutrient state and trophic structure in arid areas with major changes in water level in the past century.

Above right: Lake level changes in the Konya Basin,Turkey. Water extraction for agriculture has led to the loss of wetlands and shallow lakes. In sinkholes (central photo) the groundwater level drop (20m) is visible (Photos: Meryem Beglioglu)


Riparian Wetland, IcelandREFRESH addresses effects of climate-driven changes in water level fluctuations on riparian wetlands, in particular the effects of changes in flooding regime. We will divert the water flow at experimental stream sites to create a gradient of increasingly dry wetland conditions during summer and increasingly inundated conditions during winter. Along hydrological gradients within each site we will quantify hydrological characteristics, biogeochemical and ecological functioning and biodiversity. The strength of this approach is the combined set-up, in which wetland inundation is manipulated across a climatic gradient, allowing for investigation of individual climate change effects as well as their interactions. 

Left: Riparian wetland, Iceland (Photo: Merel Soons)