Springs are special habitats that host a rich biodiversity. However, they are endangered mainly because of tapping to gain drinking water. This impact is likely to increase because of the predicted reduction in precipitations. Epilithic cyanobacteria and algae are probably the most widespread photoautotrophic organisms in mountain springs beside bryophytes and lichens. Cyanobacteria comprise several macroscopic taxa as key elements of the biota which can be evaluated directly in the field. CRENODAT (2004-2008) is a comprehensive project that was carried out in the south-eastern Alps (Autonomous Province of Trento). 110 springs were sampled, located over a wide range of altitudes and on a variety of lithologies. All main morphological spring types (from helocrenes to rheocrenes) were considered. Results gained during CRENODAT and several other spring investigations suggested that bioassessment procedures should be habitat-type specific and adapted for the different geographic areas (in the case of springs, this is necessary both because of distributional patterns of some organisms and of the uneven geographical distribution of morphological spring types). In Europe, the Water Framework Directive promotes bioassessment methods in which the actual situation of aquatic environments is compared to reference situations. Therefore, the definition of spring types based on one or several groups of organisms is a fundamental pre-requisite to develop assessment methods. Hence the main goals of this paper are: to provide an outline of the assemblages of diatoms and macroscopic benthic algae (including cyanoprokaryotes) found in the main morphological spring types using fuzzy clustering; to determine the most influential environmental factors using multivariate analyses; to discuss autecological traits; and, to discuss the species richness and diversity of spring habitats. We are convinced that the bioassessment methods that we are developing for spring habitats should address not only quality issues but also ecological integrity and relevance for aquatic biodiversity conservation.
The contribution of benthic cyanobacteria and algae to the definition of spring types as a prerequisite for the development of ecological-integrity and environmental-quality assessment procedures for spring habitats
2011
Abstract
Springs are special habitats that host a rich biodiversity. However, they are endangered mainly because of tapping to gain drinking water. This impact is likely to increase because of the predicted reduction in precipitations. Epilithic cyanobacteria and algae are probably the most widespread photoautotrophic organisms in mountain springs beside bryophytes and lichens. Cyanobacteria comprise several macroscopic taxa as key elements of the biota which can be evaluated directly in the field. CRENODAT (2004-2008) is a comprehensive project that was carried out in the south-eastern Alps (Autonomous Province of Trento). 110 springs were sampled, located over a wide range of altitudes and on a variety of lithologies. All main morphological spring types (from helocrenes to rheocrenes) were considered. Results gained during CRENODAT and several other spring investigations suggested that bioassessment procedures should be habitat-type specific and adapted for the different geographic areas (in the case of springs, this is necessary both because of distributional patterns of some organisms and of the uneven geographical distribution of morphological spring types). In Europe, the Water Framework Directive promotes bioassessment methods in which the actual situation of aquatic environments is compared to reference situations. Therefore, the definition of spring types based on one or several groups of organisms is a fundamental pre-requisite to develop assessment methods. Hence the main goals of this paper are: to provide an outline of the assemblages of diatoms and macroscopic benthic algae (including cyanoprokaryotes) found in the main morphological spring types using fuzzy clustering; to determine the most influential environmental factors using multivariate analyses; to discuss autecological traits; and, to discuss the species richness and diversity of spring habitats. We are convinced that the bioassessment methods that we are developing for spring habitats should address not only quality issues but also ecological integrity and relevance for aquatic biodiversity conservation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
