Canopy transpiration rates in eutrophic wetlands dominated by sedges (Carex spp.) differ in a species specific way

Sedges (Carex spp.) often dominate the vegetation of wetlands. Therefore kn owledge of their gas exchange is needed for an accurate calculation of the canopy transpiration in such wetlands. Within the frame of an extended comp arative ecological study of Carer species the leaf gas exchange was investi gated porometrically in Carer riparia, C. acutiformis and C. hirta. Models to calculate leaf conductance (g(l)) for the different sedge species are us ed together with microclimatic and biomass data from a large sedge stand fo r upscaling of transpiration rates to canopy level. The species specific di fferences in stomatal conductance and transpiration are clearly identifiabl e at canopy level. Depending on species, canopy transpiration is up to 25% higher or lower. This makes it necessary to take species specific differenc es into account in wetland hydrology. (C) 2000 Elsevier Science Ltd. All ri ghts reserved.