A top-down approach for the development of a stream typology
based on abiotic variables
Martial Ferre
´
ol, Alain Dohet*, Henry-Michel Cauchie & Lucien Hoffmann
Public Research Center-Gabriel Lippmann, Environment and Biotechnologies Research Unit, 41, rue du Brill,
L-4422, Belvaux, Luxembourg
(*Author for correspondence: E-mail: dohet@lippmann.lu)
Key words: mesological characterisation, stream typology, multivariate analysis, classification, ordination techniques
Abstract
The management of aquatic ecosystems requires stream-type specific assessment systems, which enable the
partition of natural spatial variability and consequently an optimisation of monitoring and assessment
programs. Two different approaches are generally used to construct such typologies. In a top-down
approach, environmental variables are chosen on previous knowledge of the general topography of the
landscape. In a bottom-up approach, analyses of aquatic communities are used for grouping the streams. In
the present study, a typology for LuxembourgÕs streams is defined with the top-down approach i.e., with
abiotic criteria and thus criteria different from those necessary for the assessment of biological conditions
(i.e., biotic assemblages). This typological determination is based upon a combination of classification and
ordination procedures. A particular emphasis was put on variable characterisation. The results show that
six different water stream types were identified using our databases. Typological descriptors are stream
dimension, elevation as well as geology. Organic charge, slope and land use rather characterise sites within
groups. So, types are defined with criteria independent from any anthropogenic influence or pressure. Such
a typology is expected to be relevant for analysing aquatic biota in order to build up a model for the
biomonitoring of streams.
Introduction
The ecological classification of streams has a long
tradition in Europe. Besides works trying to
define, from upstream to downstream, successive
zones (zonation theory) characterised by relative
homogeneous aquatic assemblages and delimited
with relevant abiotic variables (Huet, 1949; Illies &
Botosaneanu, 1963; Verneaux, 1973; Statzner &
Higler, 1986), systems attempting to characterise
homogeneous stretches of streams are described
(Pennak, 1971; Persoone, 1979; Wright et al.,
1984).
The basic idea of the river continuum concept
(RCC) initiated in the USA (Vannote et al., 1980)
consists in linking on one hand a continuous
gradient of physical factors, mostly generated by
stream morphology and hydrology and on the
other hand, biological strategies of benthic inver-
tebrates with the dynamics of nutrient inputs and
their utilisation by functional feeding groups of
invertebrates.
These two theories, zonation and RCC,
enabled a significant progress in our understand-
ing of the functioning of stream ecosystems but
none of them provides definitive solutions, as they
focus on different aspects of stream ecology
(Botosaneanu, 1988). From an exhaustive critical
review of main typological methods, Wasson
(1989) also concluded that a practical typological
strategy should combine different approaches: (1)
using quantitative data on biota and biological
Hydrobiologia (2005) 551:193–208 Ó Springer 2005
J.N. Beisel, L. Hoffmann, L. Triest & P. Usseglio-Polatera (eds), Ecology and Disturbances of Aquatic Systems
DOI 10.1007/s10750-005-4461-2