The biotic conception of aquatic ecosystem control

A.P.Levich

 Departament of Biology, Subfaculty of Zoology of Vertabrates

 and General Ecology, Moscow State University, Moscow, 119899,

 Russia.

Key words: Ecosystem state; Estimation biotic parameters;

Ecological standartization.

The biotic conception of aquatic ecosystem control rests on

a special analysis of the passive "experiment" conducted by man-

kind for decades with natural objects at locations of human resi-

dence and economic activities.

The conception requires two groups of techniques to be deve-

loped. The first one includes integral methods for estimating

ecosystem conditions using the norm-pathology scale. The second

group contains methods of determination search and pattern recog-

nition in the multidimensional space of ecological factors aimed

at singling out the boundaries between the fields of normal and

pathological functioning of ecosystems. These boundaries have be-

en named the ecologically tolerable levels (the ETL) of distur-

bing influences.

The ETL norms fill in the deficiency of information obtained

conventionally in the form of maximum admissible concentrations

(MAC) of contaminating substances. The ETL make it possible to

extrapolate the normative base to the areas where the MAC concept

is ecologically inefficient. The ETL show how the real populati-

ons of communities inhabiting natural ecosystems respond to dis-

turbances. The organisms' responses which create the ETL are con-

nected not with separate chemical substances but, instead, with

the whole amount of factors acting on the biota, including the

chemical, hydro- and aerological, climate and radiation ones. The

boundaries of normal functioning singled out are regional rather

than universal, they reflect the specific features of a given

area, its background characteristics and the adaptive potential

of the organisms belonging to specific ecosystems.

The problems solved using the ETL norms and methodology

(normalization of contaminating substance release, heat and radi-

ation pollution, ecological run-offs and over-boundary transport;

ecological justification of environmental protection measures,

design, expert examination, monitoring, forecasting and zoning)

are entirely consistent with the tasks of the state environmental

control system.

The methods suggested are oriented of the currently existing

databases, so that they are applicable without additional invest-

ments to expensive observation systems.

In the recent years the conditions have been formed allowing

the biotic conception to be efficiently used: the databases col-

lecting the ecological observations of many years have been for-

med; there have appeared hardware and software means needed for

dealing with large amounts of ecological information; the experi-

ence of estimating the ecosystem conditions has been gained.

A computer expert system, arranged on the basis of the bio-

tic conception, makes it possible to solve the ecological control

problems and to create possibilities to improve the ecological

conditions of specific objects of nature.

The term "environment control" implies a complex of measures

providing the estimation of ecological conditions of natural ob-

jects, the normalization of factors affecting the ecosystems and

ecological zoning of economic and geographic territories.

The present environment control system in the whole territo-

ry of the former Soviet Union rests on the norms of maximum ad-

missible concentrations (MAC) of contaminating substances. These

norms are determined in laboratory experiments on isolated popu-

lations belonging to a few test species and employ selected phy-

siological and behavioral reactions of organisms. Due to their

determination methods these norms possess numerous shortcomings

(Abakumov & Sushchenia, 1991) of which the most significant ones

are the following:

- The extrapolation of laboratory experiments with test ob-

jects to natural multi-species systems is incorrect.

- Evidently in nature there does not exist an isolated inf-

luence of factors, whereas MAC are determined only under an iso-

lated action of each factor.

- The MAC exist only for chemical substances, although a bi-

ota is subject to both the substrate contamination and tens of

factors of non-chemical origin (hydrological, biological, climate

ones, etc.).

- The MAC are used as unique norms for enormous administra-

tive areas (all the regions of the former USSR), while the biotic

action of contaminating substances and other envi ronmental fac-

tors depends on specific climate, landscape, economic and many

other characteristics of a specific territory. Therefore a real

practical application of the unique MAC in regions with different

ecological conditions is impossible.

- The sufficiently expensive investigations of several re-

cent decades have established, for instance, nearly a thousand of

MAC for reservoirs of economical and general usage and nearly se-

ven hundred MAC for fish-breeding reservoirs, whereas the anthro-

pogenic contaminating substances number in the millions of names

and annually a quarter of a million of new chemical substances

are synthesized. Moreover, when sewage from different enterprises

gets into a reservoir, new substances of various chemical nature

are formed, which affect the biocoenoses in a fundamentally dif-

ferent way as compared with the original components. New compo-

unds may be more toxical than the original ones and can have a

mutagenic and carcinogenic effect.

The shortcomings of the MAC conception have been known for a

long time, so a constructive problem setting should consist not

in a criticism of the obsolete approach but rather in developing

a concrete complex of methods of control able to replace the

existing ones.

Many grudges against the MAC conception would have been in-

consistent if the normalization experiments had been conducted:

- not on separate organisms but on populations and communities

really participating in natural ecosystems;

- not with an effect of an isolated chemical substance but with

that of an entire complex of factors acting on a given ecosys-

tem;

- in the specific conditions of a concrete region, with its back-

ground and other specific characteristics.

The only type of experiment which meets the above require-

ments is the passive "experiment" conducted by mankind for a long

time at the places where people live, manage their economy and

affect the real ecosystems of the Earth's biosphere. The possibi-

lity to use the data of this "experiment" is conditioned by the

three requirements:

1. Databases are necessary, containing sufficient information on

both the biotic parts of ecosystems and the abiotic factors

potentially affecting the living organisms.

2. It is necessary to have a system of estimates of the ecologi-

cal condition of the ecosystem's biotic part, based on genera-

lized ecological indicators replacing the physiological and

behavioral indicators used in laboratory determinations of

MAC.

3. Methods are necessary which make it possible, knowing the es-

timated condition of the biota, to select the causes of bad

condition among the environmental factors and for each of the

factors to point out the boundaries whose violation would con-

vert a good ecosystem condition into a bad one.

The present circumstances provide the fulfillment of the

above requirements:

- The databases containing natural ecosystem observational data

for many years have been formed.

- A number of integral estimation methods for the conditions of

different types of ecosystems have been developed and approved.

- Hardware and software computer information technologies have

been developed, allowing the necessary ecological databases to

be analyzed.

According to the biotic conception of environmental control

the ecological conditions on the norm-pathology scale must be es-

timated by a complex of biotic parameters and not by the levels

of abiotic factors. The abiotic factors, such as contaminations

and other chemical characteristics, climate variables, transport

intensities, should be treated as the agents affecting the popu-

lations of organisms and their mutual ecological connections.

The biotic conception implies the existence of a cau-

se-and-effect connection between the level of influence on a bio-

ta and the latter's response. Namely, certain levels of action

provide normal ecosystem functioning while other levels naturally

lead to pathological conditions. A task of the biotic approach is

to find out in the abiotic factor space the boundaries between

the fields of normal and pathological functioning of natural ob-

jects. Such boundaries have been named the ecologically tolerable

levels (ETL) of disturbing influences.

To realize the biotic conception of ecological control it is

necessary to develop two groups of techniques. The first of them

includes the integral estimation methods for the ecological con-

ditions of natural objects on the norm-pathology scale. The se-

cond group contains the ecological data processing methods: se-

arch for determinations and pattern recognition in the multidi-

mensional space of ecological factors, aimed at pointing out the

boundaries between the fields of normal and pathological ecosys-

tem functioning.

The condition estimation methods turn out to be specific for

different types of ecosystems. For fresh waters one may use the

Water Quality Classifier (Organization ..., 1992) or the more mo-

dern Ecological Modification Method (Abakumov, 1991). For sea

ecosystems the necessary estimation methods may be obtained as

the further developed Desirability Function Method (Maximov & Ka-

itala, 1986) or the Method of Integral Characteristics (Mikhai-

lovsky, 1988). For soil coenoses the Method of Microbiological

Diagnostic Indicators (Zviagintsev & Guzev, 1986) deserves atten-

tion. For estimating the biota condition under atmospheric air

contamination the necessary methodology may be developed on the

basis of the Lichenometry Methods (Insarova & Insarov, 1989). A

complex effect of water, air, food and other factors on ecosys-

tems, including the human population, may be characterized adequ-

ately enough by the Human Mortality Coefficients (Gavrilov & Gav-

rilova, 1991).

The ecological norms of environmental abiotic factors are

calculated using the ETL Method. The method rests on the optimal

pattern recognition procedures and multidimensional statistical

and determination analysis. Its aim is to single out the fields

of normal ecosystem functioning in the multidimensional factor

space and to build the boundaries of these fields. Just such bo-

undaries would be considered as the ETL. Environmental changes

beyond the ETL convert the ecosystem from a good, favorable con-

dition to a bad one.

The ETL method allows one to single out from the whole set

of abiotic factors the ones significant for ecological troubles

of natural objects. The significant factors are ordered according

to their contributions to the ecological trouble and their ETL

are calculated. For the insignificant factors ecologically safe

ranges are indicated within which the ecosystem state in its for-

mer history has been manifestly good. The method allows one to

analyze the influence of the conditions of all previous years on

the current-year ecosystem condition and to calculate seasonal

ETL chronograms (for instance, water flow hydrograms).

The ETL method resolves rather complicated contradictions

emerging in multi-criterion approaches to the estimation of water

object ecological conditions. The conditions obtained from diffe-

rent criteria or from different users' goal functions are as a

rule contrary to each other. To produce a single integral estima-

te one has to resort to certain tricks, such as averaging of es-

timates, introduction of weight factors or just postulating the

priority of certain criteria over others on the basis of expert

views. The ETL method makes it possible, instead of an artificial

unification of different estimation techniques, to work indepen-

dently with each of them and to transfer the procedure of result

unification from a confrontation of estimates to an analysis of

ETL resulting from each separate estimation. To single out an ac-

tual normative the ETL method suggests the maximum severeness

criterion: for a multi-profile use of a natural object it is sug-

gested to apply as a normative the most severe ETL among those

calculated from different ecological condition estimation crite-

ria. The same principle is applicable when it is necessary to ma-

ke a choice between the coexisting ETL and MAC norms.

An essential feature of the ETL method is that it is orien-

ted at the existing databases and, being aimed at the ecological

normalization efficiency increase, requires neither additional

investments to the expensive monitoring system arrangement, nor a

delay needed for such an arrangement; it subtends a gradual modi-

fication of the existing system, increasing the fraction of bio-

logical monitoring.

I would like to enumerate some peculiarities of the biotic

conception of ecological control as compared with the existing

approaches:

- The ETL conception allows the whole practically formed MAC-ba-

sed methodology of estimating the nature management strategies

by the resulting concentration of contaminating substances to

be preserved; herewith it implies a more adequate and enriched

content of the very concept of "ecological admissibility".

- The determined boundaries of the normal functioning field ref-

lect the response of populations and communities inhabiting re-

al natural ecosystems rather than separate laboratory orga-

nisms.

- This response is caused not by isolated chemical substances but

by the entire complex of factors affecting the biota of a given

ecosystem, the chemical aero- and hydrodynamic, climate, biolo-

gical and radiation ones.

- The determined boundaries are not universal but reflect the

specific features of a given area, its background characteris-

tics and the adaptation potential of organisms belonging to

specific ecosystems. However, the ETL norms do not apply to lo-

cal objects (such as, e.g., a river section or a small river)

but to a large geographic region such as a basin or subbasin of

a big river.

- The actual factors may include ones whose existence is unknown

to the researchers working according to a certain monitoring

program, as well as factors ignored by the present program. In

such a case an ecological trouble revealed by biotic indicators

and an analysis of its causes using the ETL method may serve as

a signal that the data describing the ecosystem under study are

incomplete.

- The ETL method takes into account the effects of factors acting

on the biota, delayed by months and years, whereas in MAC de-

terminations even the duration of chronic experiments is as a

rule no greater than 6 to 8 months.

- The ETL take into account both direct and indirect influences

of factors on the biota.

- In the MAC conception the instantaneous or cumulative values of

substance concentrations are determined. Unlike that, the ETL

values are calculated both for factor values averaged over the

necessary period (seasonal, month averaged and others) and for

values extreme (maximal or minimal) for a chosen period. Thus

both current and emergency releases of substances may be norma-

lized.

- The ETL conception is efficient only for those abiotic factors

for which sufficient databases have been formed and whose ob-

served variation ranges include the values violating the ecolo-

gical well-being. It should be noted that these requirements

are met by the main contaminating substances and other basic

anthropogenic actions. These factors have been included in the

existing observation programs just due to their significance.

For these factors the ETL, employing the already existing data-

bases, may replace the expensive MAC refinements and modifica-

tions.

- MAC determinations remain an indispensable element of the eco-

logical control system for substances which have not been inc-

luded in the monitoring programs, for newly synthesized conta-

minating substances, so that the corresponding databases had no

time to form, and in cases when a consumer needs criteria of

substance action upon organisms which are not included in the

list of biotic characteristics used to estimate the ecological

condition (for instance, influences on separate fish species,

on human physiological characteristics, etc.).

The biotic control conception, when realized, allows a broad

range of urgent problems of ecologically safe nature management

to be solved:

- Creation of registers of ecological conditions of natural ob-

jects on the basis of estimates obtained from biotic identifi-

ers.

- Ecological normalization of anthropogenic and natural influen-

ces on ecosystems (contamination, heat pollution and consequen-

ces of climate changes, environment souring and alkalinization,

water consumption rates, biogenic elements, etc.), taking into

account the management category of a natural object (e.g., a

preserve, a recreation zone, an economic territory, a damping

zone and others).

- Normalization of over-boundary contamination transport.

- Forecasting and extrapolation of ecosystem conditions according

to anthropogenic action scenarios.

- Ecological zoning (by the state of natural objects, by environ-

mental factors significant for an ecological trouble, by ETL

values) and mapping.

- Arrangement of ecological investigations and expert studies.

- Ecological justification of nature protection measures and the-

ir priority levels.

- Justification of territory ecologi cal observation programs,

exposure of observation incompleteness in the existing monito-

ring programs.

To realize in practice the biotic conception of environment

control for each type of ecosystem (fresh-water, sea, soil,

on-ground, human) in each region a computer expert system should

be created, including a management database incorporating biotic,

climate, chemical and other ecological data (on the basis of the

existing databases); algorithms of estimating the ecological con-

dition of natural objects on the norm-pathology scale should be

worked out, along with a recognition algorithm for the normal

functioning field in the environmental factor space. Such a sys-

tem would enable the wide-range specialists in regions to effici-

ently solve the above ecological control and nature management

problems. In addition, an expert system would provide the creati-

on of various plans aimed at improving the ecological condition

of each specific natural object and calculation of economic, so-

cial and other efficiency indices of the proposed methods.

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