RICERCA ITALIANA     

Contribution of meiofauna to marine biodiversity of the Italian coasts

Università degli Studi di Sassari

Abstract

Meiofauna is one of the potentially more promising fields in marine research. Among other aspects, it constitutes a veritable 'new frontier' of systematic studies (it only needs to mention that all the newly described phyla belong to the meiofauna!), and its contribution to marine biodiversity is particularly significant. This notwithstanding, the number of researchers in the field is dwindling worldwide. Such 'taxonomic bottleneck' appears particularly stigmatizable, considering the widespread phenomena of global change, which are affecting our planet. In fact, the synergism of temperature rise, range shift and other stresses, in particular habitat destruction, introduction of exotic species, and spreading of pathogens, could disrupt the connectedness among species and lead to a reformulation of species communities, reflecting differential changes in species, and to numerous extirpations and possibly extinctions. Meiofauna taxa, characterized by short life cycles, fast metabolic rates, limited distribution (at least in the cases in which the application of techniques of molecular taxonomy has contributed to the resolution of sibling species complexes) and lack of dispersal larval stages, appear as ideal candidates to follow the evolution of the process in the sea. A paradox is thus evident, with the faunistic group, which could represent a useful indicator of the effects of global change on marine communities, which is in reality the most poorly known fraction of the whole >>>

Principal Investigator

Marco CURINI GALLETTI Università degli Studi di SASSARI

Research Objectives

The recent Symposium on Marine Biogeography of the Mediterranean (XXXIV Congresso SIB, Ischia, October 21-24, 2002) evidenced that i) present state of knowledge of systematics and biogeography of meiofauna groups is among the poorest of the whole Italian fauna, and that ii) this lack of knowledge is particularly regrettable, considering the overwhelming contribution of meiofauna to marine biodiversity (Bianchi & Morri, 2002). Furthermore, such 'taxonomic bottleneck' raises particular concern, at the light of recent phenomena of global change that are affecting our planet. As a consequence of present climatic changes, in fact, we can expect future latitudinal shifts in the marine biota of 300-600 km in the next 50 years (Southward et al., 1995; Warwick & Turk, 2002). The synergism of rapid temperature rise, range shift, and other types of stress, such as habitat destruction and introduction of exotic species, could lead to a reformulation of species communities and to numerous extirpations, and possibly extinctions (Root et al., 2003). Documentation of the process in the sea is however mostly based on vagile species (often particularly conspicuous, such as fishes) or with planctonic larval stages, where it might be difficult to discriminate between long-term range shift from accidental reports outside the normal range of the species. On the contrary, range shifts in more sedentary species follow from slow processes of population extinctions and colonizations, factors that >>>

First Results

Expected results of Phase 1 are as follows:
- Accomplishment of qualitative and quantitative sampling campaigns in the three areas chosen;
- Identifications of sites in marine caves, dysoxic environments and carbonatic sediments suitable for research; accomplishment of a preliminary series of samplings;
- Samplings in selected extra-italian areas;
- Accomplishment of the analyses possible on fresh samples; fixation of material for further analyses;
- Identification of target species for phylogenetical studies, population genetic structure, and reproductive biology experiments;
- Standardization of experimental protocols for genetic markers;
- Production of preliminary faunistic inventories of meiofauna groups for the areas studied; in particular, the first inventories of marine Rotifera for the whole Mediterranean will be produced.At the end of Phase 2, the main expected results will be:
- Contribution to the faunistic knowledge of protected areas of major naturalistic interest, by means of the elaboration of checklists and catalogues of lesser-known invertebrate groups, which are generally neglected in faunistic surveys;
- New and pre-existing faunistic and distributional data will allow a better estimate of the global biodiversity of the Italian seas. Moreover, data acquired during the research will provide information for assessment and monitoring of the effects caused by climatic and ecological changes >>>

Timescale

24 months

National and international background

The overwhelming value of biodiversity as an indication of environmental health and for the functioning of ecosystems is now largely documented (cf Culotta, 1996; Johnson et al., 1996). However, while numerous studies have addressed the issue of conservation of biodiversity on land, marine habitats have so far received much less attention (Cognetti & Curini Galletti, 1993; Ormond, 1996; Carlton et al., 1999; Bianchi & Morri, 2000). It is now clear that marine ecosystems are equally at risk, and that those marine ecosystems that receive the most sustained and unrelenting pressure from human activities are particularly vulnerable (Roberts et al., 2002). The few documented cases of extinction of marine animals, which concern vertebrates (mainly mammals and birds) and very few macroinvertebrates, restricted to brackish habitats or excessively exploited commercially (Roberts & Hawkins, 1999), are among the factors responsible of the delayed awareness of the urgency to protect marine biodiversity. This may reflect intrinsic differences of the marine environment compared to terrestrial habitats, namely the high connectivity of the marine system, and a generally much higher population size. A growing awareness is however rising, that present perception of marine biodiversity is woefully inadequate, which makes assessment of its modifications during time, impossible (Sala, 2002). Recent, intensive taxonomic research has revealed that even the contribution to marine biodiversity of >>>