Tarasova O., Sukhovolsky A., Soldatov V., Sukhovolsky V. Temporal and spatial conjugacy of the development of xylophage insects outbreaks in the forests of Krasnoyarsk Region // Principy èkologii. 2019. № 3. P. 101‒122. DOI: 10.15393/j1.art.2019.9062


Issue № 3

Original research

pdf-version

Temporal and spatial conjugacy of the development of xylophage insects outbreaks in the forests of Krasnoyarsk Region

Tarasova
   Olga Viktorovna
D.Sc., Siberian Federal University, olvitarasova2010@yandex.ru
Sukhovolsky
   Andrey Alexandrovich
Siberian Federal University, beorn-orcs@mail.ru
Soldatov
   Vladimir Vladimirovich
Forest Protection Center of Krasnoyarsk Region, soldatov@protect.akadem.ru
Sukhovolsky
   Vladislav Grigoryevich
D.Sc., V.N.Sukachev Institute of Forest SB RAS, soukhovolsky@yandex.ru
Keywords:
insects
xylophages
population dynamics
outbreaks
risks
temporal conjugacy
spatial conjugacy
correlation matrix
Summary: The purpose of the study is to identify the temporal and spatial syncronization of development of xylophage insect outbreaks in the forests of Krasnoyarsk Region. For the analysis, we used the data on the accounting of the areas of xylophages foci in Krasnoyarsk Region from 2007to 2014. During this time, 46 outbreaks zones of fifteen species of xylophage insects were observed. Correlation matrices were calculated, by which the spatial conjugacy of a separate species in different territories and the temporal conjugacy of different species in one territory were estimated. Based on the conjugacy data on the outbreaks zones of individual species of xylophage insects in various forest areas of Krasnoyarsk Region and the conjugacy of population dynamics of different insect species in separate forest areas of Krasnoyarsk Region, it will be possible to significantly simplify the procedure of forest entomological monitoring of territories.

© Petrozavodsk State University

Received on: 17 May 2019
Published on: 01 October 2019

Introduction

Among the phytophagous insects that inhabit forests, most species have very low population densities, when the damage to forage plants is very rare or absent. But there is a group of species whose population size can change by 5-7 orders every few years. A large part of the forest insects with periodic changes in the number of populations refers to a group of coniferous- and leaf-eating insects and causes severe defoliation of forage plants, but rarely – their death. However, mass reproduction of coniferous- and leaf-eating insects and the weakening of the forest lead to the growth of stem pests-insects number that feed on bark and wood tissues. In Siberia, foci of stem pests are often formed after outbreaks of mass reproduction of the Dendrolimus sibiricus. Insects-stem pests accelerate the process of death of plants and stands in general.

The purpose of this work is to identify the spatial and temporal synchronization of the development of outbreaks of mass reproduction of xylophage insect species complex in the forests of the Krasnoyarsk region. This analysis is necessary to assess the risks of outbreaks and the optimization of the monitoring of xylophage insects that damage forest stands. Knowing the spatial relationship of outbreaks of a particular species of xylophage allows to assess the risk of outbreaks in other territories if a mass breeding site of this species is detected in a separate forest area. The knowledge of the temporal conjugation of the development of outbreaks of several xylophagous species in a separate forestry makes it possible to assess the risks of breeding foci of other xylophagous species when detecting outbreaks of mass reproduction of other species in this forestry.


Materials

The data on damage of forest plantations and information on forest pests were collected during ground surveys of current forest pathology forest plantations by the Center of forest protection of the Krasnoyarsk region in various forest areas during 2007-2015. In the process of forest pathology survey, the boundaries of forest damage, the accounting of the number of pests, assessment of insect damage to forest stands was carried out. The pathological examination of forests inhabited by stem pests was carried out by employees by visual inspection of weakened areas of the forest. The population of plantations with stem pests was estimated by the presence of shrunken and shrinking trees, by the withering of needles in the crown, the presence of drill flour on the bark, crawling beetles, and entrance and exit holes. An area where the number of trees inhabited by stem pests exceeds 10 % is considered to be a source of stem pests (Лесная энтомология, 2010).

In the course of forest pathology surveys in the forest Fund of the Krasnoyarsk territory, foci of mass reproduction of 15 species of xylophages were found, in particular such species of stem pests as Dicerca aenea L., Melanophila guttulata Gebl. (Coleoptera, Buprestidae), Monochamus urussovi Fisch., Monochamus sutor L., Monochamus galloprovincialis Ol., Saperda carcharias L. (Coleoptera, Cerambycidae), Xylechinus pilosus Ratz., Tomicus minor Hartig., Tomicus piniperda L., Dendroctonus micans Kug., Polygraphus proximus Blandf., Scolytus ratzeburgi Jans., Ips sexdentatus Boern., Ips subelongatus Motsch. Ips typographus L. (Coleoptera, Scolytidae).

In table. 1 the data on the area of stem pest foci in forest stands in the territory of forest districts of the Krasnoyarsk territory (unpublished materials of the annual reports of the forest protection Center Krasnoyarsk region) is shown.

 

Table 1. Areas (ha) of damage to forest stands by insects-xylophages in the territory of Krasnoyarsk Region

 

Species of insect-

xylophages

Forestry Areas (ha) of insects-xylophages damage foci by years
2007 2008 2009 2010 2011 2012 2013 2014
1 Polygraphus proximus Achinskoye 0 0 753.5 753.5 863.5 1009.4 1681.4 984.5
2 Monochamus urussovi Achinskoye 0 13.7 13 13 13 13 13 13
3 Monochamus urussovi Balakhtinskoye 0 41.5 35.3 33.2 0 0 0 0
4 Tomicus piniperda Bogotolskoye 0 0 0 54 0 0 0 0
5 Polygraphus proximus Bogotolskoye 0 0 474.6 474.6 474.6 474.6 143.3 115.3
6 Xylechinus pilosus Bogotolskoye 0 54 54 54 54 54 0 0
7 Monochamus urussovi Bogotolskoye 0 373.8 350.8 350.8 350.8 350.8 25 25
8 Tomicus minor Boguchanskoye 10 0 0 0 0 0 0 0
9 Monochamus sutor Boguchanskoye 3 0 0 0 0 0 0 0
10 Polygraphus proximus Bolshemurtinskoye 0 0 0 0 0 0 475 475
11 Polygraphus proximus Bolsheuluyskoye 0 0 0 0 0 0 676.3 676.3
12 Ips subelongatus Borskoye 50 17.5 17.5 17.5 0 0 0 0
13 Monochamus urussovi Verhne-Manskoye 0 659 659 609 609 609 609 609
14 Ips sexdentatus Verhne-Manskoye 20 20 66 979 979 979 933 933
15 Dicerca aenea Gremuchinskoye 45 45 0 0 0 0 0 0
16 Ips subelongatus Gremuchinskoye 41 41 41 5.4 5.4 188.1 78.4 30.2
17 Ips sexdentatus Gremuchinskoye 423 213.6 213.6 213.6 213.6 213.6 213.6 213.6
18 Tomicus minor Gremuchinskoye 298 297.8 297.8 23.1 15.2 15.2 15.2 80
19 Tomicus piniperda Gremuchinskoye 39 25.1 25.1 0 23.1 259 121.3 48.6
20 Monochamus sutor Gremuchinskoye 4 4 4 4 4 4 4 4
21 Melanophila guttulata Gremuchinskoye 0 0 45 45 45 45 45 96.3
22 Saperda carcharias Gremuchinskoye 0 0 0 0 0 35 35 12.8
23 Xylechinus pilosus Gremuchinskoye 0 0 0 15.2 0 0 0 0
24 Monochamus urussovi Gremuchinskoye 0 3287.4 3279.6 3241.2 3241.2 3241.2 3203.2 3203.2
25 Scolytus ratzeburgi Dzerzhinskoye 0 0 0 0 0 0 22 0
26 Monochamus urussovi Dzerzhinskoye 0 0 0 0 0 2 2 2
27 Tomicus minor Divnogorskoye 16 0 0 0 0 0 0 0
28 Monochamus urussovi Dolgomostovskoye 0 95.3 95.3 205.3 110 110 110 110
29 Ips subelongatus Dolgomostovskoye 24 24 24 24 0 0 0 0
30 Scolytus ratzeburgi Dolgomostovskoye 1 0.7 0.7 0.7 0 0 0 0
31 Polygraphus proximus Emelyanovskoye 0 0 0 0 0 0 109.2 1785
32 Monochamus urussovi Eniseyskoye 0 10081 10144 1711 2227 2227 831 831
33 Monochamus urussovi Ermakovskoye 0 3280.4 3280.4 3280.4 3280.4 3280.4 3140 3140
34 Ips sexdentatus Irbeyskoye 206 206 206 206 206 206 206 206
35 Tomicus piniperda Irbeyskoye 21 21 21 0 21 12 12 12
36 Tomicus minor Irbeyskoye 0 0 0 21 0 0 0 0
37 Monochamus urussovi Irbeyskoye 0 35508 35508 35508 35508 27250 26520 0
38 Monochamus urussovi Kazachinskoye 0 7750 150 150 0 0 0 0
39 Ips sexdentatus Karatuzskoye 0 0 0 0 0 295 295 295
40 Monochamus urussovi Karatuzskoye 0 4065 4065 3434 3434 3567 1732 1732
41 Ips sexdentatus Kizirskoye 0 0 0 5.8 5.8 5.8 5.8 5.8
42 Monochamus urussovi Kizirskoye 0 798 2961.1 2669.3 2650.9 2496.2 2496.2 2048.2
43 Ips subelongatus Kodinskoye 84 84 84 84 84 84 84 84
44 Ips sexdentatus Kodinskoye 31 23.4 23.4 23.4 23.4 23.4 23.4 23.4
45 Tomicus piniperda Kodinskoye 1580 1580 1580 0 1580 1580 1580 1529.8
46 Scolytus ratzeburgi Kodinskoye 0 92 92 92 92 92 92 92
47 Dicerca aenea Kodinskoye 0 360 0 0 0 0 0 0
48 Melanophila guttulata Kodinskoye 0 0 360 360 360 360 360 360
49 Tomicus minor Kodinskoye 0 0 0 1580 0 0 21.2 21.2
50 Monochamus urussovi Kodinskoye 0 2391 2391 2391 2391 2391 2293 2578.9
51 Polygraphus proximus Kozulskoye 0 0 724.5 884.2 887.5 505.4 1196.3 1174.6
52 Monochamus urussovi Kozulskoye 0 3.9 3.9 3.9 3.9 3.9 0 0
53 Tomicus minor Krasnoyarskoye 30 0 0 0 0 0 0 0
54 Tomicus piniperda Krasnoyarskoye 17 0 0 0 0 0 0 0
55 Polygraphus proximus Krasnoyarskoye 0 0 0 0 0 0 366.3 366.3
56 Monochamus urussovi Krasnoyarskoye 0 89.5 84 84 0 0 0 0
57 Monochamus urussovi Maganskoye 0 83 83 82.5 82.5 82.5 82.5 82.5
58 Scolytus ratzeburgi Manzenskoye 4 0 0 0 0 0 0 0
59 Ips subelongatus Manzenskoye 21 0 0 0 0 0 0 0
60 Dendroctonus micans Manzenskoye 5 0 0 0 0 0 0 0
61 Monochamus urussovi Manzenskoye 0 67.1 48.5 22 22 22 22 22
62 Dicerca aenea Manskoye 123 123 103 54 54 54 8 8
63 Ips sexdentatus Manskoye 978 1084.4 1025.9 1291 1305.9 1231.9 1181.9 1280.9
64 Melanophila guttulata Manskoye 0 0 0 7 0 0 0 0
65 Polygraphus proximus Manskoye 0 0 0 0 0 0 0 5.1
66 Monochamus urussovi Manskoye 0 574.2 571.4 598.1 583.2 583.2 583.2 583.2
67 Monochamus sutor Manskoye 0 0 0 14.9 0 0 0 0
68 Polygraphus proximus Mininskoye 0 0 0 0 0 0.4 707.22 749.1
69 Monochamus urussovi Mininskoye 0 8.1 8.1 8.1 0 0 0 0
70 Monochamus urussovi Motyginskoye 0 42143.6 40644.6 40361.6 40361.6 40361.6 35780.6 15342
71 Ips typographus Nazarovskoye 27 16.2 0 0 0 0 0 0
72 Polygraphus proximus Nazarovskoye 0 0 0 0 0 0 1522.4 1470.4
73 Ips subelongatus Nevonskoye 4 4.2 4.2 4.2 4.2 4.2 4.2 4.2
74 Tomicus minor Nevonskoye 119 98.9 86.3 21.4 49.9 49.9 161.9 123.9
75 Tomicus piniperda Nevonskoye 39 39.4 39.4 0 21.4 21.4 21.4 21.4
76 Scolytus ratzeburgi Nevonskoye 3 3 3 3 3 3 3 3
77 Melanophila guttulata Nevonskoye 0 0 0 0 0 0 245.5 245.5
78 Xylechinus pilosus Nevonskoye 0 0 0 49.9 0 55 55 55
79 Monochamus urussovi Nevonskoye 0 104.9 104.9 104.9 104.9 104.9 137.9 137.9
80 Ips sexdentatus Pirovskoye 87 87 87 87 87 87 87 70
81 Ips typographus Pirovskoye 1125 1207.6 1052.6 1052.6 1052.6 1052.6 869.5 731.2
82 Tomicus minor Pirovskoye 43 72.6 72.6 48 59.6 59.6 59.6 59.6
83 Tomicus piniperda Pirovskoye 31 48 48 0 48 48 48 34.4
84 Scolytus ratzeburgi Pirovskoye 97 97 97 97 97 97 97 0
85 Polygraphus proximus Pirovskoye 0 0 0 0 0 0 3 3
86 Xylechinus pilosus Pirovskoye 0 0 0 59.6 0 0 0 0
87 Monochamus urussovi Pirovskoye 0 5570.2 5532.7 5532.7 5532.7 5532.7 5343.2 3442
88 Xylechinus pilosus Sayano-Shushenskoye 1 1 1 53.9 0 0 0 0
89 Dicerca aenea Sayanskoye 16 16.3 0 0 0 0 0 0
90 Tomicus minor Sayanskoye 107 82.4 53.9 0 53.9 53.9 53.9 53.9
91 Melanophila guttulata Sayanskoye 0 0 16.3 16.3 16.3 16.3 16.3 16.3
92 Monochamus urussovi Sayanskoye 0 1.2 0 0 0 0 0 0
93 Monochamus urussovi Severo-Eniseyskoye 0 330.5 330.5 309.2 25.9 25.9 25.9 5.9
94 Monochamus urussovi Sayano-Shushenskoye 0 956 956.1 956.1 0 0 956.1 956.1
95 Monochamus sutor Tayozhinskoye 73 68.9 24.9 24.9 20 20 20 20
96 Polygraphus proximus Tayozhinskoye 0 0 0 0 0 0 275 355
97 Monochamus urussovi Tayozhinskoye 0 2252.7 2135.2 1953.9 1310.4 1289.7 1281.4 1281.4
98 Ips subelongatus Teryanskoye 0 0 0 0 0 0 93.2 93.2
99 Tomicus piniperda Teryanskoye 0 0 0 0 0 0 70 70
100 Monochamus urussovi Teryanskoye 0 759 759 759 759 759 654 654
101 Ips subelongatus Tungusso-Chunskoye 48 30.7 30.7 30.7 30.7 0 30.7 30.7
102 Ips sexdentatus Tungusso-Chunskoye 74 0 0 0 0 0 0 0
103 Tomicus minor Tungusso-Chunskoye 0 0 0 27.1 0 0 0 0
104 Tomicus piniperda Tungusso-Chunskoye 0 28.6 27.1 0 27.1 27.1 27.1 27.1
105 Monochamus urussovi Tungusso-Chunskoye 0 0.6 0.6 0.6 0.6 0.6 0.6 0.6
106 Monochamus sutor Tyuhtetskoye 4 4 4 4 4 4 4 4
107 Polygraphus proximus Tyuhtetskoye 0 0 0 0 0 38.3 306.3 278
108 Monochamus urussovi Tyuhtetskoye 0 173 173 173 173 173 172.5 172.5
109 Ips subelongatus Uzhurskoye 7 7 7 7 7 7 7 7
110 Monochamus urussovi Uzhurskoye 0 35 35 35 35 35 35 35
111 Melanophila guttulata Usinskoye 0 0 0 0 0 91 91 91
112 Ips sexdentatus Usinskoye 0 0 0 0 0 209 209 209
113 Monochamus urussovi Usinskoye 0 0 0 0 0 1499 1499 1499
114 Monochamus urussovi Usolskoye 0 1666 1666 39 39 39 39 39
115 Tomicus minor Uyarskoye 14 14 14 0 0 0 0 0
116 Monochamus urussovi Uyarskoye 0 346.5 346.5 0 0 0 0 0
117 Tomicus minor Khrebtovskoye 0 0 0 0 0 0 0 0
118 Tomicus piniperda Khrebtovskoye 0 84 84 84 84 84 84 84
119 Monochamus urussovi Khrebtovskoye 0 768 768 768 717 717 717 717
120 Tomicus minor Chunskoye 291 281 281 0 0 0 0 0
1121 Monochamus sutor Chunskoye 3 1.5 1.5 1.5 1.5 21.5 21.5 21.5
1122 Scolytus ratzeburgi Chunskoye 61 0 0 0 0 4 4 4
1123 Dendroctonus micans Chunskoye 0 0 0 0 0 0 31 31
1124 Monochamus urussovi Chunskoye 0 1552 0 0 956.1 956.1 17 17

 

 


Methods

In any community consisting of a large number of species, it is unlikely that any environmental factor affects only one species in the entire community. The effect of an environmental factor and the simultaneous reaction of several species to it may indicate the presence of an interaction between species, about possible connectivity into a complex within a community, about the presence of conjugation of population dynamics. This correlation is revealed as a correlation between the quantitative characteristics of species populations. There are two main types of contingency: the temporary conjugation of several species in one habitat and spatial conjugation of population dynamics of one species in different habitats. The temporal correlation is shown in the fact that the dynamics of the number of different species of the complex can occur synchronously in the same habitat, such as the rise in the number of Bupalus piniaria and the complex of phyllophages related to this species in the Krasnoturansky Bor in the Krasnoyarsk territory (Пальникова и др., 2014). The spatial conjugacy of a particular species can be characterized, for example, by the number of forest areas where outbreaks of its mass reproduction are observed at a given time.

When studying the spatial conjugacy of a certain species k in N = 62 habitats (forestries) during M = 8 years, the matrix A(k) = || aijk || dimension (N x M) was used, in which cell (i, j) presents data on the area of damage to the stands by species k in the i-th forestry in the j-th year. Such matrices were constructed for each of the P = 15 registered xylophage species.

When studying the temporal conjugacy of P species in habitat m, the matrix B(m)=||bijm|| of dimension (P x M) was used, in which data on the indicator of damage to plantings in this habitat by species i in year j are presented in cell (i, j). Such matrices were constructed for each of N = 62 forestries.

15 matrices A(k) were used to assess the spatial conjugation of population dynamics of an individual insect species in different habitats (forest areas). The values of correlation coefficients between rows of A(k) matrices for each of the 15 xylophage species studied were used for spatial conjugation calculations. As a result of such calculations, correlation matrices of spatial conjugacy dimension (N x N) were obtained for all 15 species of xylophages, in which a separate cell (i, j) characterized the spatial conjugacy development of outbreaks of mass reproduction of a separate xylophages species during 2007-2014 in forest areas i and j. If the absolute value of the correlation coefficient in the cell was significant according to standard statistical criteria, this indicated spatial correlations (in the case of negative values of the correlation coefficient – anticonjugation) of the development of foci of individual species in the two forest areas i and j. A positive value of the correlation coefficient in the cell of the correlation matrix indicated that with the emergence of the focus of mass reproduction of individual species within the forest area a similar lesion appears in another forest. If the correlation coefficient is negative, the appearance of a focus in one forest area was associated with the absence of a focus of the studied species in another forest area.

62 correlation matrices B(m) were used to estimate the time conjugacy of mass reproduction of different xylophage species in the same forest area. The values of correlation coefficients between rows of B(m) matrices were used for calculations. If the correlation coefficient was positive, it indicated that the presence of one species of the xylophage complex was a factor that influenced the appearance of another species, i.e. the presence of a temporary conjugation in the population dynamics between different xylophage species in the same habitat (forestry). If the correlation coefficient was negative, it indicated that the presence of one species in the focus did not affect the appearance of another species.

The statistical package Statistica 6.0 was used to calculate correlation matrices. The statistical significance of each correlation coefficient in the correlation matrices was estimated at the level of p = 0.90. If a separate correlation coefficient in the correlation matrix turned out to be insignificant at the selected level p, then it was concluded that there was no spatial synchronism of damage to plantations by pests of the same species in different habitats or a temporary synchronization of damage to plantations by pests of several species in one habitat.


Results

Time synchronization characterizes a situation when in a single territory outbreaks of several species are observed. For xylophages, this effect may be associated with changes in the state of forage woody plants on the territory. Different forestries in the Krasnoyarsk territory differ in the number of registered centers of mass reproduction of xylophages. The "record holder" for the number of foci of different species of xylophages is the Gremuchinsky forestry, where during 2007-2014 there were foci of mass reproduction of 11 species of xylophages. Also, a large number of foci of different species of stem pests were observed in the territories of the Kondinsky, Pirovsky, Mansky and Nevonsky forestries. In 11 forestries the centers of mass reproduction of only one species was observed; in 16 forestries there were no outbreaks of mass reproduction of xylophages in 2007-2014.

The distribution of forestries by the number of centers of mass reproduction of various species of xylophages is shown in Fig. 1. In almost two-thirds (65.6 %) of the total number of forestries (61), the number of xylophage enters does not exceed 2.

 

Fig. 1. Distribution of forest areas in Krasnoyarsk region by the number of outbreaks of various xylophages species

 

Distribution of centers of mass reproduction of xylophages in the territory of The Krasnoyarsk region depends on the natural and climatic conditions in which the forests are located. In table. 2 the characteristics of the occurrence of stem insect foci depending on the forest-plant area in which the forestry is located are given (Государственный доклад..., 2018).

 

Table 2. Occurrence of outbreaks of various species of xylophages depending on the forest-plant zone in which the forestry is situated 

Forest-plant zone Total number of forestries Number of forestries with registered outbreaks of mass breeding The share of forestries with centers of mass reproduction The average number of recorded outbreaks of breeding on a forestry
Taiga zone 17 12 0.71 4.75
Forest-steppe zone 36 28 0.78 2.79
South Siberian mountain zone 9 5 0.55 2.00

 

The share of forest areas with centers of mass reproduction of stem pests for the taiga zone is 71 %; for the forest-steppe zone - 78 %, for the South Siberian mountain zone – 55 %. In all three forest zones, the average number of registered xylophage mass breeding centers is at least 2. For the taiga zone it is 4.75, for the forest-steppe zone – 2.79, for the South Siberian mountain zone – 2. Different types of xylophage insects differ greatly in the area of territories where their mass breeding centers appeared and operated (table. 3).

 

Table 3. Maximum annual area (ha) of xylophage foci in the territory of Krasnoyarsk 

Species rank Xylophagous insect species Maximum annual area of outbreaks, ha
1 Monochamus urussovi 153085.0
2 Polygraphus proximus 8437.6
3 Monochamus galloprovincialis 7050.3
4 Ips sexdentatus 3250.7
5 Tomicus piniperda 2031.5
6 Ips typographus 1223.8
7 Tomicus minor 928.0
8 Melanophila guttulata 809.1
9 Ips subelongatus 314.0
10 Scolytus ratzeburgi 218.0
11 Dicerca aenea 184.0
12 Monochamus sutor 87.0
13 Xylechinus pilosus 55.0
14 Saperda carcharias 35.0
15 Dendroctonus micans 31.0

 

From the data of the table. 3 it can be seen that the size of the centers of mass reproduction of different species of xylophages differed significantly. Thus, the maximum annual area of foci of mass reproduction of Monochamus urussovi (153085 ha) is almost 5000 (!) times more than the maximum annual area of Dendroctonus micans foci (31 ha).

As an example of calculating the time conjugation of the occurrence of foci of mass reproduction of various xylophage species in one forestry, in the table 4 it is shown the area of damaged forest plantations (ha) on territory of Gremuchinsky forestry (data are selected from table 1). In the course of forest pathological surveys of forest plantations during 2007-2014, 9 xylophage species were observed in the Gremuchinsky forestry. The mass reproduction of Xylechinus pilosus was noted only once, and the area of the plantations damaged by it was just over 15 hectares. Saperda carcharias propagated in mass during 2012-2014, damaging stands on a small area. Every year in the plantations of the Gremuchinsky forestry there are foci of Ips sexdentatus, Tomicus minor, and Monochamus urussovi (since 2008). Complex centers of mass reproduction of xylophages are formed as a result of the increase in the number of 5-6 species of insects at the same time. Since 2012, 7 xylophage species have been registered simultaneously in outbreak foci (see table. 4).

 

Table 4. Areas (ha) of outbreak foci of various species of insects-xylophages on the territory of the Gremuchinsky forestry 

Xylophagous insect species The area of foci (ha) of stem insects by years
2007 2008 2009 2010 2011 2012 2013 2014
Dicerca aenea 45 45 0 0 0 0 0 0
Ips subelongatus 41 41 41 5.4 5.4 188.1 78.4 30.2
Ips sexdentatus 423 213.6 213.6 213.6 213.6 213.6 213.6 213.6
Tomicus minor 298 297.8 297.8 23.1 15.2 15.2 15.2 80
Tomicus piniperda 39 25.1 25.1 0 23.1 259 121.3 48.6
Melanophila guttulata 0 0 45 45 45 45 45 96.3
Saperda carcharias 0 0 0 0 0 35 35 12.8
Xylechinus pilosus 0 0 0 15.2 0 0 0 0
Monochamus urussovi 0 3287.4 3279.6 3241.2 3241.2 3241.2 3203.2 3203.2

 

By the data from the table. 4, according to the above calculation method, the correlation matrix of the time conjugation of foci of different xylophage species in the territory of this forestry was calculated (table. 5).

  

Table 5. Correlation matrix of the temporary conjugation of xylophage outbreaks in the Gremyachinsky forestry 

№ of species Xylophagous insect species *
1 2 3 4 5 6 7 8 9
1 1.000 -0.134 0.655** 0.737* -0.258 -0.814* -0.403 -0.218 -0.642
2   1.000 -0.088 -0.220 0.976* -0.005 0.804* -0.331 0.085
3     1.000 0.483 -0.136 -0.533 -0.264 -0.143 -1.000*
4       1.000 -0.405 -0.590 -0.559 -0.308 -0.464
5         1.000 0.123 0.881* -0.321 0.129
6           1.000 0.313 0.064 0.516
7             1.000 -0.264 0.249
8               1.000 0.142
9                 1.000

Note. * – species: 1 – Dicerca aenea, 2 – Ips subelongatus, 3 – Ips sexdentatus, 4 – Tomicus minor, 5 – Dendroctonus micans, 6 – Melanophila guttulata, 7 – Saperda carcharias, 8 – Xylechinus pilosus, 9 – Monochamus urussovi. ** – correlations are significant at the level of p = 0.90.

 

As it is known, for species i and j, the correlation coefficient r (i, j) = r (j, i), so the correlation matrix is symmetric with respect to the main diagonal, and data below the main diagonal can be omitted. As shown in table 5, there may be a positive conjugacy of the occurrence of foci of two species in the same forestry (the correlation coefficient r > 0 and is significant at the level of p = 0.90) and a negative conjugation of foci of two species in the same forestry (r < 0 and is significant at the level of p = 0.90). In the first case, if there is a focus of one species in the forestry, for the most part a focus of a positively conjugate species is also found. Thus, the centers of mass reproduction of the Ips subelongatus (species 2) and the Tomicus piniperda (species 5) are positively associated. For these species, the correlation coefficient r (2, 5) = +0.976. The centers of mass reproduction of Ips subelongatus (species 2) and Saperda carcharias (species 7) are positively associated too. For these species, the correlation coefficient r (2, 7) = + 0.804.

In a case of negative conjugacy, if there is a focus of one species, the foci of another species do not occur. This is the case with the foci of Ips sexdentatus (species 3) and the Monochamus urussovi (species 9). For these species, the correlation coefficient r (3, 9) = - 1.0.

On the basis of calculations of time conjugation correlation matrices of foci of mass reproduction of the xylophage insect complex in various forestries of the Krasnoyarsk territory, a positive conjugation in the dynamics of a number of xylophage species was revealed (table 6).

M. galloprovincialis (see table 6) is the species that is associated with the largest number of foci of other species-xylophages of this complex. This species forms conjugate foci with 10 other species, of which the foci of Monochamus galloprovincialis and Scolytus ratzeburgi are most often interconnected. Monochamus galloprovincialis damages all coniferous trees, but most strongly – the scotch pine. When passing additional nutrition in the crowns of trees, beetles gnaw the bark of thin branches, which significantly weaken the trees during mass reproduction. In addition to coniferous trees, beetles can damage branches and hardwoods such as birch and aspen. Scolytus ratzeburgi is widespread and damages, as a rule, old and weakened birch trees. Since these species do not compete for food resources, the conjugacy of their foci, according to Moran (1953), may be related to the common requirements for climatic conditions.

 

Table 6. Positive temporary conjugation of foci of certain types of xylophages 

Xylophagous insect species The number of conjugated species The most common interconnected species
Monochamus galloprovincialis 10 Scolytus ratzeburgi
Tomicus piniperda 8 Tomicus minor
Ips sexdentatus 8 Monochamus galloprovincialis
Monochamus urussovi 8 Monochamus galloprovincialis
Scolytus ratzeburgi 7 Monochamus urussovi
Melanophila guttulata 6 Dicerca aenea
Polygraphus proximus 6 Monochamus urussovi
Dicerca aenea 5 Melanophila guttulata
Ips subelongatus 5 Monochamus galloprovincialis
Ips typographus 4  
Tomicus minor 4 Monochamus galloprovincialis
Dendroctonus micans 3  
Xylechinus pilosus 3 Tomicus piniperda
Saperda carcharias 2  
Monochamus sutor 2  

 

Quite a large conjugation with foci of other species is characteristic for Tomicus piniperda, Ips sexdentatus and Monochamus urussovi. The number of related stem insect species with these three species is 8. At the same time, the most frequently paired species are Tomicus minor and Monochamus galloprovincialis.

Tomicus minor as Tomicus piniperda are found in the area of pine everywhere. The beetles feed on weakened trees. Their settlement area – the peaks, large branches, and the central part of tree trunks of various ages. In addition, the Tomicus by "haircut" weakens healthy, not yet populated by it pine trees, thereby preparing the base for further setting.

Tomicus piniperda attack weakened pines, often form foci on burning areas, in the foci of the pine fungus, in conditions of development pressure. These species belong to the spring phenological complex of stem pests.

Monochamus urussovi develop in all coniferous species. Beetles additionally feed on needles and bast on the shoots and branches of living trees. Monochamus urussovi in the forests of Siberia and the far East, breeds in huge number in Siberian silkworm foci, in burning areas, and in areas of large logging operations. All Monochamus inhabit both standing and fallen trees (Лесная энтомология, 2010). These species can act as competitors, but still form conjugate (complex) foci. This is due to the fact that the Tomicus piniperda, Tomicus minor, and Monochamus are capable of additional feeding in the imaginal phase. Additional feeding is carried out by beetles on shoots and branches viable trees, weakening them and expanding their food base. In addition, the joint mastering of woody plants by different species of xylophages allows to overcome the resistance of the physiological tree systems (Исаев, Гирс, 1975).

The spatial conjugacy of outbreaks of mass reproduction of a particular species can be characterized by the number of forest areas where outbreaks of its mass reproduction are observed. So, the centers of mass reproduction of Monochamus urussovi met in 36 forestries, Monochamus galloprovincialis – in 20, Tomicus minor and Polygraphus proximus – in 13 forestries. Among the most common species in the territory of the region are the Tomicus piniperda and Ips typographus (in 10 forest districts). Saperda carcharias with a 35-hectare outbreak was recorded on the territory of one forestry (see table 1). The reasons for spatial conjugation can be the synchronization of population dynamics and the state of forage plants, the similarity of the reaction of populations to weather changes in different habitats.

The risk of outbreaks of mass reproduction of a particular xylophagus species in the territory in the region can be characterized using the following indicators: the share of forest areas where outbreaks of this species occur, indicators of the conjugacy of outbreaks of this species in different forestries, the area of outbreaks of mass reproduction of this species in relation to the total area of forest plantations. The higher these values, the more risk of outbreaks of this species of xylophage.

As an illustration, we present an assessment of the risk of an outbreak of mass reproduction of Monochamus urussovi in forest areas in the Krasnoyarsk territory during 2007-2014.

Having data on the area of outbreaks of Monochamus urussovi in the forestry space of the Krasnoyarsk territory and time (2008-2014) (table 7), one can calculate the correlation matrix of spatial conjugation of Monochamus urussovi outbreaks in various forestries in the Krasnoyarsk territory. In table 8 a fragment of this correlation matrix is given (it is difficult to give the entire correlation matrix due to its large size).

The analysis of table 8 allows to identify areas with synchronous centers of mass reproduction of Monochamus urussovi. For example, the dynamics of development of the outbreaks of Monochamus urussovi matches in Gremuchinsky, Eniseysky and Usolsky forestries (correlation coefficients more than 0.78), whereas temporal dynamics of the development of outbreak of this species anticorrelated in Achinsky and Kizirsky forestry. Thus, the share of forestries where outbreak of this species is observed is equal to 0.581. For the entire complex of xylophages considered, information on the area of outbreaks and the percentage of forestries where outbreaks occur is given in table 9.

The risks of developing outbreaks of mass reproduction of various xylophage species in the territories of different forestries can be represented graphically in Fig. 2, where on the abscissa axis in this graph is the share q of forestries in which outbreaks of this species are observed, and on the ordinate axis is the logarithm of the share S0 of the area of foci of this species from the total territory of the whole forests region. A point on the plane characterizes a separate species. For example, there are points that characterize the Monochamus urussovi (point 1), Monochamus galloprovincialis (point 2), and Ips sexdentatus (point 3).

Points in the lower left corner of the plane {q, ln S0} characterize species with a low level of impact on the forest (the percentage of forest areas where these xylophage species occur is small, and the areas of foci are small). Thereto group belong the majority of species of studied entomocomplexes: Dendroctonus micans, Saperda carcharias, Xylechinus pilosus, Monochamus sutor, Dicerca aenea, etc. Points in the upper right corner of the plane {q, ln S0} characterize the xylophagous species with a strong impact on the forest (the centers of mass reproduction of these species occur in most forestries on the territory of Krasnoyarsk region and the area of centers are large). Species from this group include Monochamus urussovi, Monochamus galloprovincialis, Tomicus minor, Polygraphus proximus. In the upper-left corner of the plane {q, ln S0} on Fig. 2 there should be points that characterize locally impacting species (occurring in a small number of forestries, but the areas of centers in these forestries are large). In the lower right corner of the plane {q, ln S0} there should be points that characterize diffusely affecting species with centers in a large number of forestries, but with a small area. However, as can be seen in Fig. 2, locally and diffusely affecting xylophage species were not found in the territory of forestries of the Krasnoyarsk region during the research period.


Discussion

The problem of the occurrence of foci and the frequency of outbreaks of mass reproduction of dendrophilic insects for many decades occupies a leading place in ecological studies in the world. In the mid-twenties of the twentieth century, ecologists put forward theoretical ideas about the periodicity of mass reproduction, their interaction with the cycles of solar activity, climate, and natural enemies (entomophages). The main factor in the dynamics of the number of stem insects is the quantity and quality of food. Weather and other ecological factors have an indirect effect on population dynamics through the state of fodder plants.

In domestic and foreign ecological literature for a long time the question is raised about the relationship of insect population cycles with climatic factors Domestic and foreign ecological literature long ago has raised the question about the relationship of insect population cycles with climate factors. It is known (Берриман, 1990) that cycles of different populations of the same species separated by large distances can take place synchronously with each other. The mechanisms that ensure a synchronous increase in the number of insect populations over a wide area are not yet known in details. It is assumed that the cause of synchronization of outbreaks of mass reproduction of insects may be some external factor, the impact of which leads to the simultaneous development of local outbreaks. In particular, such synchronizing factors can be changes in the Sun activity (Чижевский, 1973), summer droughts over a wide area (Кондаков, 1974, 2002). Since the rhythm of the solar activity determines the dynamics of the impact of solar radiation simultaneously on the entire planet, and the number of outbreaks of number of insect species are not synchronized in time and space, it is assumed that the synchronizing factor is a combination of the rhythm of solar activity and local planetary rhythms (Moran, 1953). According to different authors, the reason for the conjugation of population dynamics of one species in different habitats may be the effect of P. Moran, associated with the uniformity of climatic conditions over a large area and the similarity of the reaction of populations to weather changes in different habitats (Максимов, 1989; Bjornstad, Bascompte, 2001; Пальникова и др., 2014). It is shown (Liebhold, Kamata, 2000; Liebhold et al., 2004), that the degree of conjugation of population dynamics of one species in different habitats monotonously decreases with increasing distance between these habitats. If the level of conjugacy of population dynamics does not decrease with increasing distance between habitats, and the distance between them significantly exceeds the radius of individual movement of animals of the studied species, then we should talk about its global spatial coherence associated with the reaction of populations to the influence of a powerful modifying factor.

 

Table 7. Areas of outbreak foci for Monochamus urussovi Fisch. on Krasnoyarsk Region territory for 2008–2014 

Forestry The area of foci of Monochamus urussovi Fisch.(ha) by years
2008 2009 2010 2011 2012 2013 2014
Achinskoye 13.7 13 13 13 13 13 13
Balakhtinskoye 41.5 35.3 33.2 0 0 0 0
Bogotolskoye 373.8 350.8 350.8 350.8 350.8 25 25
В.-Manskoye 659 659 609 609 609 609 609
Gremuchinskoye 3287.4 3279.6 3241.2 3241.2 3241.2 3203.2 3203.2
Mininskoye 8.1 8.1 8.1 0 0 0 0
Dzerzhinskoye 0 0 0 0 2 2 2
D.-Mostovskoye 95.3 95.3 205.3 110 110 110 110
Eniseyskoye 10081 10144 1711 2227 2227 831 831
Ermakovskoye 3280.4 3280.4 3280.4 3280.4 3280.4 3140 3140
Irbeyskoye 35508 35508 35508 35508 27250 26520 0
Kazachinskoye 7750 150 150 0 0 0 0
Karatuzskoye 4065 4065 3434 3434 3567 1732 1732
Kodinskoye 2391 2391 2391 2391 2391 2293 2578.9
Kozulskoye 3.9 3.9 3.9 3.9 3.9 0 0
Krasnoyarskoye 89.5 84 84 0 0 0 0
Kizirskoye 798 2961.1 2669.3 2650.9 2496.2 2496.2 2048.2
Maganskoye 83 83 82.5 82.5 82.5 82.5 82.5
Manzenskoye 67.1 48.5 22 22 22 22 22
Manskoye 574.2 571.4 598.1 583.2 583.2 583.2 583.2
Motyginskoye 42143.6 40644.6 40361.6 40361.6 40361.6 35780.6 15342
Nevonskoye 104.9 104.9 104.9 104.9 104.9 137.9 137.9
Pirovskoye 5570.2 5532.7 5532.7 5532.7 5532.7 5343.2 3442
S.-Shushenskoye 956 956.1 956.1 0 0 956.1 956.1
Sayanskoye 1.2 0 0 0 0 0 0
С.-Eniseyskoye 330.5 330.5 309.2 25.9 25.9 25.9 5.9
Tayozhinskoye 2252.7 2135.2 1953.9 1310.4 1289.7 1281.4 1281.4
Teryanskoye 759 759 759 759 759 654 654
Т.-Chunskoye 0.6 0.6 0.6 0.6 0.6 0.6 0.6
Tyuhtetskoye 173 173 173 173 173 172.5 172.5
Uzhurskoye 35 35 35 35 35 35 35
Usolskoye 1666 1666 39 39 39 39 39
Uyarskoye 346.5 346.5 0 0 0 0 0
Khrebtovskoye 768 768 768 717 717 717 717
Chunskoye 1552 0 0 956.1 956.1 17 17
Usinskoye 0 0 0 0 1499 1499 1499

 

Table 8. A fragment of the correlation matrix of spatial contiguity of the foci of the Monochamus urussovi Fisch in various forestries in the Krasnoyarsk Territory 

The number of forestry The number of forestry *
1 5 7 9 16 17 20 32
1 1.00 0.60** -0.35 0.64* 0.51 -0.92* -0.42 0.65*
5   1.00 -0.76* 0.91* 0.78* -0.30 -0.51 0.85*
7     1.00 -0.60* -0.75* 0.06 0.09 -0.55
9       1.00 0.75* -0.37 -0.75* 0.99*
16         1.00 -0.25 -0.14 0.74*
17           1.00 0.31 -0.40
20             1.00 -0.76*
32               1.00

Note. * – forestries: 1 – Achinskoye, 5 – Gremuchinskoye, 7 – Dzerzhinskoye, 9 – Yeniseiskoye, 16 – Krasnoyarskoye, 17 – Kizirskoye, 20 – Manskoye, 32 – Usolskoye. ** – the correlation coefficient is significant at p = 0.90.

 

Table 9. Occurrence of outbreaks foci of certain xylophages species in forest areas of Krasnoyarsk Region during 2007–2014 

Species of insects- xylophages Maximal annual area of foci, ha Number of forestries with foci of this species Percentage of forestries with foci of this species The ratio of the areas of foci to the areas of forest plantations
Monochamus urussovi 153085 36 0.581 0.00156
Polygraphus proximus 8437.6 13 0.210 8.61*10-5
Monochamus galloprovincialis 7050.3 20 0.323 7.19488*10-5
Ips sexdentatus 3250.7 2 0.032 3.31736*10-5
Tomicus minor 2031.5 10 0.161 2.07316*10-5
Ips typographus 1223.8 10 0.161 1.2489*10-5
Tomicus minor 928 13 0.210 9.47031*10-6
Melanophila guttulata 809.1 6 0.097 8.25692*10-6
Ips subelongatus 314 9 0.145 3.20439*10-6
Scolytus ratzeburgi 218 7 0.113 2.22471*10-6
Dicerca aenea 184 4 0.065 1.87773*10-6
Monochamus sutor 87 6 0.097 8.87841*10-7
Xylechinus pilosus 55 5 0.081 5.61279*10-7
Saperda carcharias 35 1 0.016 3.57177*10-7
Dendroctonus micans 31 2 0.032 3.16357*10-7

 

Fig. 2. The risks of outbreaks of various xylophages species

 

The dynamics of the foci distribution, the synchronicity of their formation in space and the degree of synchronicity of the foci formation of different species in the same habitat are of practical importance. However, this requires materials on the inventory population outbreaks of dendrophilic species in forestries, performed by specialists. The use of spatial correlation matrices for a particular species allows, after the detection of foci of mass reproduction of this species of xylophage in a single forestry to assess the risks of outbreaks of this species in other forestries. The use of the correlation matrix of the temporal conjugation of the dynamics of several species in a separate forestry makes it possible to assess the risks of developing outbreaks of other xylophagous species in this forestry when a focus of mass reproduction of one xylophage species is detected.


Conclusions

1. The most dangerous species of xylophagous insects at risk of impact to forest stands in the Krasnoyarsk region are: Monochamus urussovi Fisch., Polygraphus proximus Blandf., Monochamus galloprovincialis Ol., Tomicus piniperda L.

2. To assess the risk of developing of conjugated foci of a number of species in a single forestry, one can use correlation matrices of time conjugation of xylophage populations. For example, for Gremuchinskoye forestry it is a high risk of concurrent development (temporary conjugation) of several species of xylophages: Ips subelongatus and Tomicus piniperda, Ips subelongatus and Saperda carcharias, Tomicus piniperda and Saperda carcharias, Dicerca aenea and Tomicus minor, Dicerca aenea and Ips sexdentatus.

3. To assess the risk of spatial conjugation of mass reproduction of a particular species of xylophage in different forestries, one can use correlation matrices of spatial conjugation of foci of this species. The highest degree of spatial conjugation of foci is typical for Monochamus urussovi, Monochamus galloprovincialis, Polygraphus proximus. This indicates the spatial distribution of these species, one should expect the simultaneous appearance of breeding centers of these species on the territory of different forestries.


References

Berriman A. Forest protection from insects pests. M.: VO Agropromizdat, 1990. 288 p.

Bjornstad O., Bascompte J. Synchrony and second order spatial correlation in host–parasitoid system, Journal of Animal Ecology. 2001. Vol. 70. P. 924–933.

Chizhevskiy A. L. Eath's echo of solar storms. M.: Mysl', 1973. 349 p.

Forest entomology: textbook for University students, E. G. Morozova, A. V. Selihovkin, P. P. Izhevskiy i dr.; pod red. E. G. Mozolevskoy. M.: Izdatel'skiy centr «Akademiya», 2010. 416 p.

Isaev A. S. Girs G. I. Tree and insects-xylofages interaction. Novosibirsk: Nauka, 1975. 348 p.

Kondakov Yu. P. Outbreaks of Siberian silkworm in the forests of Krasnoyarsk Region, Entomologicheskie issledovaniya v Sibiri. Krasnoyarsk: KF REO, 2002. Vyp. 2. P. 25–74.

Kondakov Yu. P. Regularities of outbreaks of Siberian silkworm. Novosibirsk: Nauka, 1974. P. 206–265.

Liebhold A., Kamata N. Are population cycles and spatial synchrony universal characteristics of forest insect population?, Population Ecology. 2000. Vol. 42. P. 205–209.

Liebhold A., Sork V., Peltonen M., Koenig W., Bjørnstad O. N., Westfall R., Elkinton J., Knops J. M. H. Within-population spatial synchrony in mast seeding of North American oaks, Oikos. 2004. Vol. 104. P. 156–164.

Maksimov A. Natural cycles: the causes of recurrence of ecological processes. L.: Nauka, 1989. 236 p.

Moran P. A. P. The statistical analysis of the Canadian lynx cycle. II. Synchronization and meteorology, Australian Journal of Zoology. 1953. Vol. 1. P. 291–298. DOI: 10.1071/zo9530291.

Pal'nikova E. N. Suhovol'skiy V. G. Tarasova O. V. Temporal and spatial coherence of population dynamics of forest insects phyllophages, Evraziatskiy entomologicheskiy zhurnal. 2014. No. 13 (3). P. 228–236.

State report " about the state and protection of the environment in Krasnoyarsk Region in 2017". Krasnoyarsk, 2018. P. 171–172. URL: http://mpr.krskstate.ru/dat/File/3/doklad%202017. pdf.


Displays: 2064; Downloads: 393;