The lentic–lotic character of Mediterranean rivers and its importance to aquatic invertebrate communities

Abstract

Hydromorphological features are crucial in structuring habitats for freshwater organisms. The quantification of these variables is often performed through accurate measuring or detailed estimation, but their assessment is not always feasible for river management purposes. Economic and time constraints often lead to difficulty in creating simple summaries of collected data for practical use. The Lentic-lotic River Descriptor (LRD) was developed to identify the character of a river site in terms of local hydraulic conditions. Information about the presence of flow types, channel substrates, in-stream vegetation, organic debris and artificial features is included in its calculation. The main aim of this paper is to investigate whether the lentic-lotic character of a river site, as summarized with the LRD descriptor, is relevant to aquatic invertebrate communities in nearly natural river sites. Invertebrate data were collected with multi-habitat, proportional sampling and hydromorphological information was gained by applying the CARAVAGGIO method (river habitat survey technique) in the field. The dataset was generated from High or Good ecological status river sites located in Mediterranean areas of Italy. Correspondence Analysis was performed to relate the invertebrate community structure to a set of catchment-scale, reach-scale and chemical environmental variables. The results of the multivariate analysis indicate that LRD provides a persuasive explanation of the most important axis of variation in benthic data. This paper also presents the optimal LRD range for a set of invertebrate taxa, accompanied by a short discussion of their potential use in conservation issues.

Non-perennial Mediterranean rivers in Europe: Status, pressures, and challenges for research and management

“…408 Ric. 20.03.2002-Settore "RISORSE IDRICHE", 2003-2005, the concept of lentic-lotic character of rivers was developed (Buffagni et al, , 2010. Later on, the INHABIT project (LIFE08 ENV/IT/000,413, 2010-2014 -www.life-inhabit.it) dealt explicitly with NPRS of Sardinia, focusing on lentic-lotic riverine habitat components, so that they can be effectively considered when classifying rivers, as well as planning and checking the effect of RBMP Program of Measures (PoMs).…”

“…Water abstraction, for example, favours lentic habitat conditions, thereby affecting the structure and traits of aquatic assemblages (Buffagni et al, 2010;García-Roger et al, 2013). Gallart et al (2012) developed a new approach to analyse the regime types of NPRS in relation to their controls on the composition and structure of aquatic biota.…”

“…This tool can also be applied when hydrological data are missing, using the taxonomic and biological trait composition of the macroinvertebrate community as predictors. Likewise, Buffagni et al (2010) stressed that the lentic-lotic character of rivers (e.g. quantified by proxies such as the Lentic-lotic River Descriptor (LRD) score system, see Buffagni et al, 2009) has to be taken into account when assessing their ecological status.…”

High Variability Is a Defining Component of Mediterranean-Climate Rivers and Their Biota

“…Community changes between the wet and the dry season in Mediterranean-climate regions have been reported for many aquatic organisms, including microbes (e.g., [58]), phytoplankton (e.g., [59,60]), benthic algae (e.g., [61][62][63], macroinvertebrates (e.g., [19,64,65]), and fish (e.g., [44,47,63]), and for riparian vegetation (e.g., [66]). Nevertheless, macroinvertebrates are by far the most investigated group and studies on seasonal changes have focused on whole communities as well as the composition of particular taxonomic groups (e.g., Plecoptera [67]; Trichoptera [68]; or Chironomidae [69]).…”

“…Seasonal community changes in Mediterranean rivers reflect habitat changes between the wet and the dry season [65]. The onset of the dry season drives habitat changes that impose new environmental filters for aquatic communities.…”