System of principles for conservation of the biogeocenotic function and the biodiversity of filter-feeders.

Abstract

An ecologically substantiated system of protectedterrestrial and water areas is an essential component ofbiodiversity conservation [1].Studies by many authors [2–4] and our own works[6, 7] showed that filter-feeders play an important rolein elimination of suspended particles from water and itspurification. Therefore, filter-feeders provide habitatsfor other species in aquatic ecosystems. This impliesthat the problem of conservation of the filtration func-tion in the population of hydrobionts should be prop-erly taken into account when developing the system ofconservation of terrestrial and aquatic areas.The goal of this work was to formulate and substan-tiate the suggestion that the system of protected terres-trial and aquatic areas should be supplemented by sitesintended to conserve the filtration function of filter-feeding hydrobionts (filter-feeders of zoobenthos, inparticular). An additional goal of this work was to for-mulate and substantiate the system of basic principlesand conditions of their protection.Emphasis should be placed on the following aspectsof this problem: the state of the population of filter-feeders (bivalve mollusks, in particular); the factorsmaking it necessary to protect populations of filter-feeders; and basic requirements for the conditions oftheir protection. The state of the populations of filter-feeders (asexemplified by bivalve mollusks).Some species of bivalve mollusks are included inthe Red Data Books of Russian Federation (34 taxa, in2000) [8] and some other states of the former SovietUnion. In the North America and Western Europe,many populations of bivalve mollusks are also endan-gered and included in the IUCN Invertebrate Red DataBook [9].In many aquatic ecosystems, there is a trend towarda decrease in the populations and biomass of bivalvemollusks at polluted sites. This concerns both freshwa-ter [7] and marine [4] ecosystems.The state of filter-feeding hydrobionts should betaken into account in the context of the general state ofaquatic ecosystems. Even in some reserves, the state ofmany aquatic ecosystems is far from satisfactory. Usingthe methods based on the morphometric characteristicsof aquatic organisms such as the roach ( Rutilus rutilus )and the lake frog ( Rana ridibunda ), it has been shownthat the state of aquatic ecosystems in the VoronezhskiiState Natural Reserve is unsatisfactory [10]. The stateof aquatic ecosystems was also found to be unsatisfac-tory in many places outside state natural reserves: thetown of Voronezh, Lake Kostomukshinskoe (Karelia), alake in the Zheleznogorsk raion of the Kursk oblast,etc. [10]. Factors making it necessary to protect popula-tions of filter-feeders. There are several factors mak-ing it necessary to protect populations of filter-feeders(including bivalve mollusks), including:conservation of the gene pool as a part of biodiver-sity;conservation of the gene pool as a resource and areserve for aquaculture; andconservation of water self-purification in naturalwater bodies.Various aspects of conservation of the gene pool wereconsidered in the preceding works on the general prob-lems of conservation of biodiversity [11, 12] and morespecific problems of conservation of invertebrates [9].Let us consider the third factor in more detail. Therole of invertebrates in self-purification of water bodieswas studied by many researchers (for review, see [2–7,13–15]). The whole volume of water in many largeaquatic ecosystems can be filtrated by bivalve molluskswithin the time interval from 0.7 (South San FranciscoBay) to 25 days (Narragansett Bay) [5]. Within oneyear, marine bivalve mollusks are capable of eliminat-ing, from water column above 1 m