=Paper= {{Paper |id=Vol-2727/paper1 |storemode=property |title=Biometric Data Analysis for Identifying Features of the Structural and Spatial Organization of Hydrobiological Communities |pdfUrl=https://ceur-ws.org/Vol-2727/paper1.pdf |volume=Vol-2727 |authors=Anna Andrianova,Evgeniya Karepova |dblpUrl=https://dblp.org/rec/conf/sibdata/AndrianovaK20 }} ==Biometric Data Analysis for Identifying Features of the Structural and Spatial Organization of Hydrobiological Communities== https://ceur-ws.org/Vol-2727/paper1.pdf

Biometric Data Analysis for Identifying Features
of the Structural and Spatial Organization
of Hydrobiological Communities*

Anna Andrianova1,2[0000-0003-3274-3813] and Evgeniya Karepova1[0000-0002-6515-2932]
1 Institute of Computational Modelling of the Siberian Branch

of the Russian Academy of Sciences, 50/44 Akademgorodok, Krasnoyarsk, 660036, Russia
2 Krasnoyarsk Branch of VNIRO (“NIIERV”),

33 Parizhskoy Kommuny st., Krasnoyarsk 660049, Russia
andrav@icm.krasn.ru

Abstract. In the rivers of the Yenisei basin, benthic invertebrates play a major
role in feeding most Siberian valuable fish species. This report presents
advanced material on zoobenthos of the river Kan (one of the major tributaries
of the Yenisei river in its middle course). Litho-psammo-rheophilic biocenosis
of benthic invertebrates is most developed; 99 species and forms are recorded
there. The total abundance of zoobenthos is formed by mayflies, caddisflies and
chironomids, and biomass by caddisflies and mayflies. The correlation analysis
reveals a consistent variation in the abundance of structure-forming insect
orders (mayflies, stoneflies and caddisflies). The clustering of data on the
abundance of families reveals the consistency with the geographical zoning of
the river Kan and change in hydrological conditions. In the longitudinal profile
of the river, there is a change of the dominant families among mayflies in
Heptageniidae – Ephemerellidae – Ephemeridae; families of caddisflies – from
Glossosomatidae to Hydropsychidae. The water temperature during the study
period determined up to 30% of the variance in the number of stoneflies,
dipterans, and the “other” group. For caddisflies, the influence of oxygen
dissolved in water is more significant (20% of the explained dispersion).

Keywords: Rheophilic Zoobenthos, River Kan, Spatial Distribution,
Correlation Graphs, Cluster Analysis.

1 Introduction

Nowadays, the worldwide interest in biometrics is growing and the need for biometric
analysis of biological research results is increasing. Analysis of the species
relationship in communities; identification of environmental factors affecting the
formation of communities and viability of individual species as well as revealing
patterns of the spatiotemporal distribution of species and communities – all these

* Copyright c 2020 for this paper by its authors. Use permitted under Creative Commons
License Attribution 4.0 International (CC BY 4.0).
2

problems are related to the fundamental problems of ecology [1, 2] and cannot be
solved without involving statistical data analysis [3].
Zoobenthos is one of the most important elements of the ecosystems of continental
reservoirs and watercourses. Benthic invertebrates contribute to the natural self-
purification of water and reflect the ongoing changes in the environment, including
those anthropogenic in nature. In addition, zoobenthos is an important component of
the food supply for most species of Siberian fish (sturgeon, whitefish, grayling,
cyprinids, etc.), and the level of its development can be used to estimate the potential
fish productivity of water bodies, depending on the amount of available food
forbenthophage fish [4].
The purpose of the work is to analyze the spatial structure of the river zoobenthos
communities with the help of mathematical and statistical methods of data processing
using the example of the river Kan (tributary of the Yenisei in its midstream).

2 Materials and Methods

The Kan River is one of the largest tributaries of the Yenisei in its midstream, which
extends from the mouth of the river Tuba to the mouth of the river Angara. The Kan
originates on the northern slopes of the East Sayan, flows into the Yenisei from the
right bank, 108 kilometers down the city Krasnoyarsk. The length of the channel is
630 kilometers, and the water intake is 37 thousand km2. It is customary to subdivide
the Kan into three large areas: in the upper reaches, the river flows to the north; in the
middle - to the northwest, and in the lower - straight to the west. The midstream
begins approximately at the mouth of the Peso River and ends in the area of the town
Kansk. The width of the river in the upper reaches does not exceed 100 m, the most
spacious place of the channel being near Kansk (390 m), while at the mouth the width
of the river reaches 300 m. The depth of the Kan in the area from the mouth to Kansk
is 2–6 m, in the upstream the depth decreases significantly. At a distance of 98 km
from the mouth, the river is regulated by the dam of the low-pressure hydroelectric
complex of the Krasnoyarsk Regional Hydroelectric Power Plant-2. The backwater
extends upstream 15 km from the hydroelectric complex, the average depth of the
reservoir being 3.0–4.5 m. The Kan is an industrial river, which is partially navigable;
some of the nearby areas being densely populated and flooded. The largest
settlements (the towns Kansk and Zheleznogorsk) are located in the lower reaches.
Zoobenthos samples were collected at 9 stations in the river Kan in September
2015, on a river area of about 450 km in the middle and lower reaches. For each
station, water temperature, oxygen content, and soil type were recorded. The samples
were taken in the watercourse by a circular Dulkeit scraper with a capture area of 1/9
m2 and a benthometer with a capture area of 1/16 m2. The samples were washed
through a silk bolting cloth No. 28; in the field, water organisms were fixed with 80%
ethanol. The Shannon index of the species diversity was calculated from the number
of species. The analysis of biotic interactions within the benthic communities was
carried out according to two indicators: the number of the main taxonomic groups and
their share in the total number of zoobenthos. In this case, the Spearman rank
3

correlation coefficient was used, which was considered significant at p <0.05. To
assess the degree of influence of the water temperature and oxygen content on the
number of the main taxonomic zoobenthos groups, multivariate linear regression
analysis was used. The determination coefficient was considered statistically
significant at p <0.05. To study the spatial structure of the bottom communities,
clustering was made using the method of hierarchical agglomeration. The inside
cluster distance (between the stations) was calculated in the Euclidean metric, and the
intercluster distances (between the clusters) were calculated using the Ward’s method.
Clustering was performed according to two indicators: the share of the main taxa in
the total number of zoobenthos and the logarithm number of each family. In order to
avoid the appearance of a logarithm of zero, a unity was added to each number before
taking the logarithm. Statistical data processing was performed in Python 3.7.2 using
the scipy (https://scipy.org) and scikit-learn (https://scikit-learn.org/) libraries.

3 Results and Discussion

In the river Kan, stony-pebble and stony-sandy soils dominate; higher aquatic
vegetation grows locally along the banks. The developmental advantage was obtained
by the litho-psammo-rheophilic biocenosis of the bottom invertebrate animals, in
which 99 species were recorded at the time of the study. Сhironomids and caddis flies
constituted the maximum number of species (27 and 23, respectively); the second
place was occupied by mayflies (18). Small and rarely found benthos (mollusks,
amphipods, leeches, dragonflies, water mites, bugs, beetles) were combined into the
“other” group; the number of species in these taxa did not exceed 3. The richest
species composition was recorded at stations 2 and 4 (40 and 44 species,
respectively); at the other stations, 22–28 taxa were identified. The maximum
Shannon index of the species diversity was identified at the station 2 (3.77 bit/ind.),
the minimum values were recorded in the downstream of the Krasnoyarsk Regional
Hydroelectric Power Plant-2 at stations 6 and 7 (2.74 and 2.77 bit/ind., respectively).
In zoobenthos communities at other stations, the Shannon index varied insignificantly
(3.11–3.24 bit/ind.). The total number of zoobenthos was formed due to insects:
mayflies and caddis flies contributed 31% each, dipterans (mainly chironomids) –
23%. The largest share in the total biomass accounted for to caddis flies – 44%,
followed by mayflies – 24% (Fig 1).

23% Diptera 9%
10% 17%
Ephemeroptera
Plecoptera
Trichoptera 24%
31% Other

31% 6%
а) 44% б)
5%

Fig. 1. The ratio of the main zoobenthos groups in the river Kan
(a – by abundance; b – by biomass).
4

The quantitative characteristics of zoobenthos ranged from 0.3 to 3.5 thousand
ind./m2 and from 0.8 to 4.4 g/m2. In the spatial dynamics of abundance and biomass
(Fig. 2), two peaks can be distinguished: at stations 2 and 4. At station 2, the number
of chironomids and caddis biomass increased; at station 4, mayflies and caddis flies
formed for the basis of abundance and biomass. It should be noted that the bottom
communities at stations 2 and 4 were characterized not only by high density, but also
by high species diversity.

3,5 40
Abundance
35
Abundance (thous.ind./m2)

3,0 Biomass
30
2,5

Biomass (g/m2)
25
2,0
20
1,5
15
1,0
10
0,5 5

0,0 0
1 2 3 4 5 6 7 8 9 Stations

Fig. 2. The abundance and biomass of zoobenthos in the river Kan.

In the formation of the structural organization of communities, biotic interactions are
undoubtedly of great importance. The analysis of the structure of benthic
communities based on the ratio of the abundance numbers of the main large taxa
revealed a number of statistically significant patterns. In particular, the numbers of
structure-forming insect orders (mayflies, stoneflies and caddis flies) consistently
varied; dipteran insects positively correlated only with stoneflies (Fig. 3). The
maximum correlation coefficient R = 0.65 was found for a pair “mayflies – caddis
flies”.

Fig. 3. Correlation graphs of the relationships between the abundance of the main zoobenthos
taxonomic groups (gray color indicates the statistically significant Spearman correlation
coefficients at p<0.05).

It is known that the species composition and abundance of benthos depend on many
factors, including depth, flow velocity, water temperature, level fluctuations, soil,
degree of vegetation development, and others [2, 5]. As a result of the linear
regression analysis, the influence of the water temperature and oxygen content on the
abundance of the main taxonomic groups of zoobenthos was determined (Table 1).
5

The maximum share of the data variation was explained by the water temperature: 23,
27, and 31% of the total number of stoneflies, dipterans, and other groups,
respectively. Statistically significant coefficients of determination (p< 0.05) are
marked in bold.

Table 1. Coefficients of multiple determination (R2) of the abundance of the main taxonomic
groups in zoobenthos in the river Kan and hydrological indicators.

Temperature Oxygen Temperature + Oxygen
Group of animals
R2 p R2 p R2 p
Diptera 0.31 0.003 0.04 0.34 0.34 0.007
Ephemeroptera 0.08 0.15 0.12 0.07 0.20 0.07
Plecoptera 0.23 0.01 0.02 0.46 0.25 0.03
Trichoptera 0.05 0.29 0.22 0.01 0.26 0.03
Others 0.27 0.006 0.09 0.13 0.37 0.004

It is known that in rivers, as they move away from the headwater, regular changes in
the hydrobionts habitat occur, which causes the heterogeneity of the species structure
of communities along the longitudinal river profile [5, 6]. The nature of these changes
has two characteristics – gradual and steplike; the latter is usually associated with a
local influence of external factors.
The analysis of the bottom community structure in various parts of the river Kan
by the agglomerative clustering method, based on the share of large taxa in the total
zoobenthos abundance (Fig. 4a), revealed the presence of four clusters, each of them
being characterized by the dominance of one or another group of invertebrates
(mayflies, caddis flies, dipterans, or “others”).

Fig. 4. The results of the cluster analysis by the Ward method of structural organization of
zoobenthos communities at various stations in the Kan: a) – according to the portion of the
major taxa in the total abundance of zoobenthos; b) – by the logarithmic abundance of families.

Clustering of data at the level of the prologarithmic number of families (Fig. 4b)
revealed three clusters, to be consistent with the geographic zoning of the Kan river
6

and change in hydrological conditions. In the first cluster there is station 1, located in
the upper part of the middle reaches, where the river still has a pronounced mountain
character. In zoobenthos, mayflies of the Heptageniidae family, as well as caddis flies
of the Arctopsychidae and Glossosomatidae families, had an advantage. Station 8,
located in the lower reaches in the area of the Great Kansk Lip, is in the same cluster.
Here, under stormy conditions, as at station 1, the mayflies of the Heptageniidae
family were leading. The second cluster combined stations 2 and 3, where the river
enters the Kansk-Rybinsk basin and flows quietly along the wide valley of the Kansk
forest steppe, and there are many islands in the channel. Among the mayflies,
representatives of the Ephemerellidae family dominated there, among caddis flies –
Hydropsychidae and Stenopsychidae. Other stations (4–7 and 9), located in the lower
reaches of the river, formed the third cluster. At the same time, the Ephemeridae
family, in particular E. sachalinensis, whose confinement to the lower reaches was
also observed in the rivers of South Korea [7], had a clear advantage in the mayflies
order. In the river Kan, this species spread from the Yenisei, where it often dominates
in zoobenthos [8].
Thus, in the river Kan according to the longitudinal profile, a change in dominant
families was observed among the mayflies in the series Heptageniidae –
Ephemerellidae – Ephemeridae; caddis flies families – from Glossosomatidae to
Hydropsychidae. A similar pattern was revealed in the spatial distribution of benthic
communities in the watercourses of the river Ob basin [9].

4 Conclusions

The river Kan (a large tributary of the Yenisei in its middle course) in the studied area
is inhabited by cold-loving reobiont organisms, among which amphibiotic insect
larvae (stoneflies, mayflies, caddis flies, and dipterans) predominate qualitatively and
quantitatively. The maximum number of species is represented by chironomids and
caddis flies. Water temperature is one of the significant factors determining the
number of stoneflies, dipterans, and “other” group (up to 30% of the explained
variance). For caddis flies, a more significant influence of oxygen dissolved in water
was noted (20% of the explained variance). Data clustering at the level of family
numbers revealed the consistency with the geographic zoning of the river Kan and
change in the hydrological conditions. In the longitudinal profile of the river from the
upper reaches, a change in the dominant families was observed among mayflies in the
series Heptageniidae – Ephemerellidae – Ephemeridae; caddis flies families – from
Glossosomatidae to Hydropsychidae. Landscape-geomorphological features of the
river Kan in the lower reaches, determine the leading position of the species
characteristics for the upper reaches.
Acknowledgments. This work is supported by the Krasnoyarsk Mathematical
Center and financed by the Ministry of Science and Higher Education of the Russian
Federation in the framework of the establishment and development of regional
Centers for Mathematics Research and Education (Agreement No. 075-02-2020-
1631).
7

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