Global intensification of agriculture, population growth, industrialization and climate change are the main causes of biodiversity’s and its ecosystem functions’ degradation (Udawatta et al. 2019). The structure of biodiversity, especially forest cover, is a rather informative indicator of the degree of anthropogenic pressure on the natural environment. In regions with arable lands, such as the Right-Bank Forest-Steppe of Ukraine, little natural vegetation has been preserved for a long period of agricultural production. As a result of economic activity and the laying of transport networks of various types, the habitats of animals of forest and other ecosystems are fragmented and divided by anthropogenic landscapes. In small forest regions, complexes of protective plantations, first of all field protective forest shelter belts (FSB), become almost the only corridors of connection of natural ecosystems fragments, divided biotopes, remnants of natural frame of territories. Depending on the species, size, condition and other forest-assessment indicators, the forest environment necessary for the conservation and migration of wild animals is to some extent maintained in FSB (Furdychko and Lavrov 2009; Furdychko and Stadnyk 2012; Lavrov et al. 2016). However, in modern conditions of urbanization intensification, economic development of landscapes, changes in land use due to land reform, development of transport infrastructure, as well as improper care of the FSB system, their illegal cutting, anthropogenic pollution in Ukraine, their fragmentation increases, their productivity and sustainability, the period of existence reduces, which causes a significant decrease in the ability of forest belts to perform ecosystem functions (Furdychko and Lavrov 2009; Furdychko and Stadnyk 2012; Lavrov et al. 2016). Similar negative effects of human activities on protective plantations have been found in other countries (Livesley et al. 2016; Huse et al. 2016). The spectrum of human activity influences well reflects the change of different characteristics of the vegetation flora structure: taxonomic, chorological, biomorphological, coenotic and ecological. Due to the significant diversity of sensitive species with different biological and ecological characteristics, the grass layer is able to quickly, objectively and integratedly reflect the nature of changes, allows establishing their causes, synecological effect of their interaction (combined effect of factors) and predict future changes (Ramenskij 1971; Tsyganov 1983; Mirkin et al. 2001; Lavrov 2003; Zhukova et al. 2010; Voron et al. 2011; Didukh 2012; Lavrov et al. 2019). Therefore, for phytoindication of FSB violation, it is expedient to study the systematic, biomorphological and ecological characteristics of the grass tier of forest belts. Of particular concern is the possibility of the loss of rare plants and animals, endangered species in the agrolandscapes. It is expected that to some extent the conservation of biodiversity can contribute to the completion of the ecological network, in which FSB plays the role of ecological corridors, as well as organic agricultural production, which in recent years is actively developing (Lavrov 2003; Furdychko and Lavrov 2009; Lavrov et al. 2016; Grabovska and Lavrov 2019). The aim is to assess the structure of biodiversity of field protective forest shelter belts to determine the directions of increasing their reclamation and conservation potential in the organic agricultural landscape.
The study was conducted on agricultural lands of Institute of Agroecology and Environmental Management of NAAS of Ukraine (Skvyra, Kyiv region; GPS coordinates 9°41’49.6»N 29°39’46.9»E). This is the only certified demonstration site in Ukraine created within the project ‘Development of the organic market in Ukraine’ (according to FIBL agreement, since 2013). It was taken as a typical agrolandscape for the Forest-Steppe zone. Organic crops along the perimeter of the field with an area of 40 hectares are protected by four forest shelter belts of different assessment and sanitary characteristics (Fig. 1; Tab. 1). According to the physical and geographical zoning of Ukraine, the study area belongs to the North-Eastern Dnieper Upland and Kyiv Upland Regions of the Podilsk-Prydniprovsky Forest-Steppe Region. The study area is of national importance in the structure of the national ecological network.
Structure of the studied organic agrolandscape (demonstration site of Institute of Agroecology and Environmental Management of NAAS of Ukraine): OF – organic fields; CF – conventional fields; 1, 2, 3, 4 – forest shelter belts No. С1, С2, С3 – sections of the forest belt No. 4; G1, G2 – fruit gardens, G3 – dendrological garden; VG – vegetable garden; AB – administrative buildings; FY – farmyard; Р-32, Р-18 – regional routes
FSB was investigated in June 2019 by the route method around organic fields (Fig. 1). The spatial structure (construction) of forest belts, their species composition and sanitary condition of the stand were studied by forestry methods (Anuchin 1982; Sanitary rules…, 1995; Voron et al. 2011). The grass tier of the forest belts was studied taking into account the assessment and sanitary characteristics of the stand. On the typical areas of the forest shelter belts, trial plots (TP) with a length of 100 m (on both field edges and inside the forest strip) were laid. Continuous accounting of the species composition and the assessment of the total projective cover (TPC) of the grass tier were carried out there. The design of FSB and the degree of its degradation, the number of rows and ‘free’/‘empty’ seats in them (plant mortality), the height and width of the forest belt, the density of canopy, the composition of the tiers of trees, shrubs and grasses phytocenosis and also a sanitary condition of an edificatory tier of tree species are determined.
The degree of stands damage formed by several species was assessed by the state index (Ic) of the first tier for mixed stands, which was calculated by Voron et al. (2011) (formula 1):
where:
N – the total number of evaluated trees in the trial plot, individuals.
Stands with an index of 1.00–1.50 were considered healthy (no damage); weakened – 1.51–2.50 (weak damage); severely weakened – 2.51–3.50 (average damage); wilting – 3.51–4.50 (severe damage); dead – 4.51–6.00 (the damage is very strong) (Voron et al. 2011).
Vegetation was studied by methods of Mirkin et al. (2001). We identified the Latin names of vegetation taxons by Mosyakin and Fedoronchuk (1999). The biomorphological structure of vegetation is given by Serebrjakov (1962). Ecomorphic analysis was performed according to Tarasov (2012) with additions according to ‘Ecoflora of Ukraine’ (Didukh 2004). Family names are given according to the system of Takhtajan (2009).
To synecologically determine the degree of anthropogenic transformation of FSB (except
where:
Types of ecological strategies of plants were described according to the scheme of Ramensky – Grime (Grime 1977). Plant life-forms are given by Raunkiaer (Raunkiaer 1936; Mirkin et al. 2001). Projective cover of grass species was evaluated on the Brown-Blanc scale (Mirkin et al. 2001), where 1 point is up to 5%, 2 – 5–25%, 3 – 25–50%, 4 – 50–75% and 5 – 75–100%. The index of vegetation adventization (separately for trees and grass tiers) was established as a share of alien species from the total number of species in a certain test plot. Changes in ecological conditions were detected by the structure of the grass tier, using scales (Tsyganov, 1983). The effect of changes on plants in the regime of leading environmental factors – climatic (thermo(Tm), ombro- (Om) and cryo-regime (Cr), continentality (Kn)); edaphic (generalized salt regime (Tr), nitrogen (Nt) and acid (Rc) regimes, soil moisture (Hd) and its changes (fH)), as well as shading-light regime (Lc) was evaluated. The values of the regimes of ecological factors were calculated as arithmetic averages. The ecological valence of grass species was determined by Jukova et al. (2010). Their tolerance index (
Were conducted from 6.00 to 12.00 am by the common method of counting birds on routes (Järvinen and Väisänen 1975; Bibby 2000). The length of the observation line was 2300 m, the survey covered the entire width of the forest strip (4–35 m), and the total survey area was 6.6 ha. The audio definition of birds’ voices (mp3) was used for the acoustic identification of species. The average nesting density of birds, its standard deviation and variance were calculated.
The list of bird species is provided in accordance with the ‘International Code of the Zoological Nomenclature’ (International Code … 1999). Analysis of avifauna by ecological groups and trophic specialization was carried out in accordance with the method of Belik (Belik 2006, 2009). We compared the share of ecological groups of birds that are indicative for the assessment of groups, namely: the number of bird species that are subject to protection in accordance with the lists of international conventions and the Red Book of Ukraine; ecological guilds of the group, depending on the micro-stations they choose to build a nest (Snow and Perrins 1998; Camprodon and Brotons 2006; Shupova 2017; Blinkova and Shupova 2017; Blinkova and Shupova 2018). We evaluated the index of synanthropization of nesting birds’ communities, according to formula 3, proposed by Jedryczkowski (formula 3):
where:
Statistical data processing was performed using a computer program Microsoft Excel by Dospekhov (2012).
The organic fields are surrounded on the perimeter by the field protective forest shelter belts of weakened state (Tab. 1): FSB No 1 (from the west) – 4-row dense two-tier forest shelter belt with a width (B) of 20.0 m and a height (H) of 17.4 m. In the first tier, the main species is
Assessment and sanitary characteristics of field protective forest shelter belts around the organic experimental fields (Institute of Agroecology and Environmental Management of NAAS of Ukraine)
No FSB, trial plots (TP) – sections (C), placement relative to organic fields | FSB construction | Number of rows of tree species, pieces | Species composition | FSB parameters, m | Density of canopy* | Plantation condition | ||||
---|---|---|---|---|---|---|---|---|---|---|
main tent | undergrowtli and understorey | H | B | Ic | sanitary | forestry | ||||
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 |
FSB No 1, TP1, west side of the field | two-tier, dense | 4 | main speices – |
UNDERGROWTH: |
17.4 | 20.0 | 0.58 | 2.43 | weakened | good, TPC –38.1% |
FSB No 2, TP2, north side of the field | three-tier, dense | 7** | main speices – |
UNDERGROWTH: |
24.3 | 35.0** | 0.81 | 2.28 | good, TPC –25.6% | |
FSB No 3, TP3, east side of the field | one-tier, dense | 2 | main speices – |
UNDERGROWTH: |
22.6 | 16.0 | 0.72 | 2.23 | good, TPC –31.2% | |
FSB No 4, TP4-C1 south side of the field | dense | 3 | main speices – |
UNDERGROWTH: |
14.2 | 12.0 | 0.62 | 1.48 | healthy | good, TPC – 17.6% |
FSB No 4, TP4-C2 south side of the field | wind-per- meable, there are gaps in the forest belt up to 20 m wide | 1 | main speices – |
UNDERGROWTH: |
12.5 | 4.0 | 0.51 | 1.42 | healthy | satisfactory, the stand is liquefied, TPC –42.8% |
FSB No 4, TP4-C3 south side of the field | semi- permeable | 2 | main speices – |
UNDERGROWTH: |
13.4 | 8.0 | 0.55 | 1.37 | healthy | satisfactory, the stand is liquefied, TPC –26.4% |
Note: C– sections of TP are distinguished by the difference in structure (according to the degree of degradation) of the for est shelter belt No 4; * – for one-row FSB – density in a row; ** – TP2 had a projective width of 50.0 m (10 rows of trees, row spacing –5 m, between rows – shade-tolerant shrubs
FSB No 2 (from the north) is 7-row most dense three-tier forest belt (B = 35.0 m; H = 24.3 m) with developed undergrowth and understorey. In the first tier, the main species is
FSB No. 3 (from the east) is 2-row one-tier dense forest shelter belt, 16.0 m wide and 22.6 m high. The main species is
FSB No. 4 (from the south) is 1-, 2- and 3-row remnants of degraded forest shelter belt, which we divided, respectively, into three sections (C1, C2, C3). They differ in width (B = 4.0–12.0 m) and height (H = 12.5–14.2 m) of the stand; by density, which means – by field protective ability – wind-permeable, semi-permeable and dense. Now these fragments of FSB have different main species:
As an integral indicator of the species stability degree in the phytocenosis, we estimated the type of vegetative mobility of woody plants (type of vegetative reproduction). It was found that in all FSB, vegetatively sedentary and immobile species predominate (Tab. 2). That is, the conditions of the sub-canopy space do not contribute to the reproduction of vegetatively mobile species. Biological and ecological adaptations of species are integrated into the strategy of their behaviour. The life strategy (type of behaviour) of a plant is the most important characteristic of a species, which reflects its reaction to abiotic and biotic environmental conditions.
The structure of bio- and ecomorphs of FSB dendroflora
Factors | Life form | Share of species, % |
---|---|---|
Biomorphs by IG Serebryakov (1962) | trees | 77.4 |
shrubs | 21.3 | |
lianas | 1.3 | |
Type of vegetative mobility | vegetatively sedentary | 38.6 |
vegetatively immobile | 32.3 | |
vegetatively mobile | 29.1 | |
Heliomorphs | heliophytes | 64.5 |
scioheliophytes | 6.5 | |
heliosciophytes | 29.0 | |
Hydromorphs | xeromesophytes | 9.7 |
mesohygrophytes | 3.2 | |
mesoxerophytes | 12.9 | |
mesophytes | 74.2 | |
Trophomorphs | megatrophs | 12.9 |
mesotrophs | 80.6 | |
oligotrophs | 6.5 | |
of which nitrophils | 16.1 |
The studied forest belts are dominated by tree species of mixed ecological strategies, in particular violents – patients (CS, 58.3%). These are resistant to stress, lack of resources and competitively strong species of
Heliomorphs are dominated by heliophytes and heliosciophytes due to liquefaction and reproduction of the species-transformer
The structure of bio- and ecomorphs of FSB wood nitrophils
Species | Biomorph | Cenomorph | Trophomorph | Hygromorph |
---|---|---|---|---|
tree | Ru, @ | MgTr | Ms | |
bush | Sil | MgTr | Ms | |
bush | Sil | MgTr | Ms | |
bush | Sil | MgTr | MsHg | |
liana | Sil, @ | MsTr | Ms |
Notes: Ru – ruderant; @ – adventive type; Sil – silvant; MgTr – megatroph; MsTr – mesotroph; Ms – mesophyte; MsHg – mesohygrophyte.
The studied dendroflora of FSB includes 30 species from 22 genera and 12 families. Division Pinophyta is 3.3% of species, Division Magnoliophyta – 96.7% (Tab. 4). There were 77.4% of trees, 21.3% of shrubs and 1.3% of lianas. The most complete systematic structure of vegetation is reflected in the percentage of species from different families. But due to the significant imbalance of plantations, the systematic structure of the studied FSB is broken. In particular, the family
Systematic structure of FSB dendroflora
Classes and species | Number of species | Share of species (%) |
---|---|---|
Division |
||
1 | 3.2 | |
Division |
||
2 | 6.5 | |
1 | 3.1 | |
1 | 3.2 | |
1 | 3.2 | |
3 | 9.7 | |
2 | 6.5 | |
3 | 9.7 | |
8 | 29 | |
4 | 12.9 | |
3 | 9.7 | |
1 | 3.3 | |
Total | 30 | 100.0 |
Quantitative indicators of dendroflora taxa of the studied FSB in general are as follows: families – 29, genera – 24, species – 29, which belong to the Division of Magnoliophyta (30 species) and the Division of Pinophyta (1 species), including adventive species – 15, nitrophilic species – 5 (16.1%). The dendroflora adventization index is 50.0%, which is due to direct human intervention (planting of introducents), to a lesser extent – self-settlement of transformer species
It was found that plantations with developed undergrowth and understorey are weakened (TP1, TP2, TP3), 26.8–43.5% of trees have a liquefied edificatory tier due to the mortality (TP1) or it is too narrow 1–3-row remnants of degraded forest shelter belt (TP4-C1, C2, C3; Tab. 1). Over time, due to the deterioration of the main species, there was a partial change of dominants, the activization of development of the second tier (accompanying species) and the restructuring of the stands construction (TP2, TP3). Therefore, the dense of the canopy in the wide forest shelter belts is still high (0.72–0.81). This ensures the maintenance of appropriate forest conditions in these stands, favourable for birds, other species of biota, as well as sufficient potential to protect agricultural land from negative abiotic factors. The TPC of the grass tier is high in FSB No 4 (TP4; 17.6–42.8%) and in narrow 2–4-row forest shelter belts (TP1 – 38.1%, TP3 – 31.2%). In dense stands, the formation of grass is observed only in the gaps of the tree tent (TP2 – 25.6%).
Typically, in modern floristics, much attention is paid to the 10 leading families, which are a reflection of the basic properties of flora and are the main part of the spectrum of families. We found 102 vascular plants from 32 families and 85 genera in the grass cover of FSB. In the distribution of species between classes,
Comparative spectra of leading families of different flora
Family | The place of the family in the flora | |||||||
---|---|---|---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
2 | 3 | 3 | 2 | 2 | 2 | 2 | 2 | |
3 | 2 | 4 | 4 | 4 | – | 3 | 3 | |
9 | 5 | 2 | 6 | 3 | 3 | 5 | 4 | |
18 | 6 | 9 | 5 | 5 | 4 | 4 | 6 | |
6 | 8 | 5 | 7 | 5 | 7 | 2 | 5 | |
10 | 10 | 6 | 11 | 7 | 5 | 12 | 9 | |
4 | 11 | – | 10 | – | – | + | 11 | |
8 | 4 | – | 3 | 7 | – | 11 | 7 | |
19 | – | 7 | 18 | 8 | + | + | 12 | |
5 | 7 | 8 | 9 | 8 | + | 4 | 10 | |
16 | – | 10 | 12 | 6 | – | – | 13 | |
17 | 9 | – | 14 | 8 | + | 3 | 8 | |
25 | – | – | 14 | 4 | 5 | 4 | 15 | |
12 | – | – | 16 | 6 | 5 | + | + | |
+ | – | + | – | 8 | 5 | – | - | |
+ | + | + | – | 6 | 5 | – | - | |
– | + | – | + | 6 | 6 | + | - | |
– | – | – | + | – | 6 | + | + | |
– | – | – | – | 7 | 7 | + | 14 | |
– | – | – | – | 7 | – | – | – | |
– | – | – | – | 7 | – | – | – | |
– | – | – | – | 7 | – | – | – |
Notes: Flora: 1 – Holarctic (Hohrjakov 2000); 2 – Ukraine (Didukh 2004); 3 – synanthropic Ukraine (Protopopova et al. 2006); 4 – Northern Bukovina (Termena et al. 1992); 5 – FSB studied by us; 6 – FSB in the area of Cherkasy (Lavrov et al. 2019); 7 – valleys of the Tyasmin River (Lavrov et al. 2016); 8 – Left-Bank Forest-Steppe of Ukraine (regional landscape park ‘Gadyatsky’ (Poltava region, Ukraine)) (Khannanova 2015); ‘–’ – are below the 20th place; ‘+’ – are below the 15th place.
The families
According to the ratio of families depending on the degree of transformation (
Taking into account the imbalance of the systematic structure of the studied plantations, it is necessary to analyze the ratios of biomorphs of herbaceous plants, which indicates the peculiarities of the vegetation adaptation of the studied area to anthropogenic changes (Tab. 6). We found that there is almost the same number of annual species compared to perennial species. Plants species without rosettes are most common in the studied FSB. The structure of underground shoots is dominated by species without formations, then – longrhizomed, plants with a taproot system predominate. The type of vegetative mobility in FSB is dominated by vegetatively immobile species (55–57%;
The structure of life forms of the FSB grass tier
Signs forms of life | Life forms | Number, individuals | Share of all herbaceous plants on TP,% |
---|---|---|---|
Life cycle duration | Annuals | 40 | 50.6 |
Perennials | 39 | 49.4 | |
The structure of aboveground shoots | Creeping | 5 | 5.8 |
Rosette | 16 | 20.1 | |
Without rosette | 54 | 70.7 | |
Turf | 3 | 2.3 | |
Creepers (climbing) | 1 | 1.1 | |
The structure of underground shoots | Long-rhizome | 20 | 24.1 |
Short-rhizome | 16 | 19.3 | |
Without formations | 40 | 48.2 | |
Bunch-root | 7 | 8.4 | |
Type of root system | Taproot | 65 | 63.7 |
Fibrous root | 37 | 36.3 | |
Type of vegetative mobility | Vegetatively mobile | 20 | 26.3 |
Vegetatively sedentary | 13 | 16.2 | |
Vegetatively immobile | 46 | 57.5 | |
Climamorphs (Raunkier life forms) | Phanerophytes | 1 | 1.4 |
Hamephytes | 2 | 2.5 | |
Therophytes | 31 | 39.2 | |
Hemicryptophytes | 34 | 41.4 | |
Geophytes | 12 | 15.5 | |
Ratio | Therophytes/Geophytes | – | 2.4 |
– | –0.4 | ||
Heliomorphs | Heliophytes | 61 | 74.4 |
Scioheliophytes | 19 | 23.2 | |
Sciophytes | 2 | 2.4 | |
Cenomorphs (by Belgard) | Silvants | 18 | 18.4 |
Pratants | 15 | 13.1 | |
Stepants | 8 | 7.5 | |
Ruderants | 40 | 36.5 | |
Adventives | 32 | 24.5 | |
of which nitrophils (%) | 15 | 14.7 |
Thus, the analysis of the biomorphological spectrum of the grass cover of the studied FSB indicates a high degree of species diversity. Significant participation in its structure is taken by ruderants, in particular adventive species, disturbed distribution by coenomorphs. This indicates a significant flow of seeds of cultivated plants (
It is known that the strategy of the species is a variable throughout the ontogenesis of the individual (Grime 1977; Mirkin et al. 2001). We found that the studied FSB is dominated by species of transitional groups of ecological strategies, in particular plants with CR-strategy (26.5%) (e.g.,
Ecological characteristics of the biotope on the phytoindication scales of Tsyganov, points
By bionts in FSB, species of eurivalent fraction (62–65%) with wide amplitude of adaptations to environmental factors dominate. According to the tolerance index to soil conditions, hemistenovalent species and mesovalent species predominate after the eurivalent fraction (almost 30%) (Fig. 3). In total, 29 species of birds of 4 orders nest in the studied FSB, 27 of which are protected by the Bern Convention, 8 are also by the Bonn Convention, 1 additionally – by the Washington and Red Books of Ukraine (Tab. 7). There are no adventive species of birds nesting in FSB.
The ratio of grass tier species in relation to climatic and soil factors according to the index of ecological tolerance, where SB – stenobionts, HSB – hemistenobionts, MB – mesobionts, HEB – hemieuribionts, EB – euribiont species
Distribution and status of birds nesting in FSB (pairs/ha)
Species | № FSB | Protected categories | |||
---|---|---|---|---|---|
1 | 2 | 3 | 4 | ||
0.3 | Bk2; Bo1,2; W2, RBU | ||||
1.7 | – | ||||
3.3 | Bk3 | ||||
0.3 | Bk3 | ||||
0.6 | Bk2 | ||||
0.3 | Bk2 | ||||
0.3 | 1.7 | Bk2 | |||
1.7 | 1.7 | – | |||
1.3 | 0.6 | 3.3 | Bk2 | ||
1.4 | Bk2 | ||||
0.3 | 1.7 | Bk2 | |||
0.6 | 0.6 | 3.3 | Bk2 | ||
0.3 | Bk2 | ||||
0.6 | Bk2; Bo2 | ||||
0.3 | 1.7 | Bk2; Bo2 | |||
0.6 | 0.3 | Bk2; Bo2 | |||
0.6 | 0.9 | 5.0 | 3.3 | Bk2; Bo2 | |
0.6 | 1.7 | Bk2; Bo2 | |||
1.7 | 5.0 | Bk2; Bo2 | |||
0.6 | 0.6 | 1.7 | Bk2; Bo2 | ||
0.6 | 0.9 | 3.3 | Bk2 | ||
1.9 | 2.9 | 5 | Bk2 | ||
1.9 | 0.6 | 3.3 | Bk2 | ||
0.6 | 3.3 | Bk2 | |||
1.4 | 1.7 | Bk3 | |||
1.3 | 2.3 | 3.3 | Bk3 | ||
0.3 | Bk2 | ||||
0.3 | Bk2 | ||||
1.1 | Bk2 |
Notes: Bk2, Bk3 – categories of the Berne Convention list; Bo2 – category of the Bonn Convention list; W2 – category of the Washington Convention list; RBU – Red Book of Ukraine.
Dendrophils reach 93.1%, sclerophiles 6.9% of the species composition of birds (
In general, in all FSB hollow-nesting birds occupy the largest share of the group (Fig. 4). A small proportion of crown-nesting birds was found in FSB No. 1, which is also due to the absence of large trees in this stand. However, the high density of shrubs provides good protection for birds that nest on the ground, so their percentage is the highest. In general, the small share of birds that nest on the ground and in the under storey in all groups is a sign of significant anthropogenic pressure on the studied forest belts.
Distribution of birds by types of nesting strategy (%): t – crown-nesting, b – nest in understorey, h – hollow-nesting, g – terrestrial, cc – nesting parasite; 1, 2, 3, 4 – FSB
FSB No. 2 differs from others by the presence of
In all studied FSB, birds of 5 feeding types nest, the spectrum of them is completely presented only in FSB No. 2 (Fig. 5). The most common is a group of birds that feed mainly on invertebrates, which are classified as entomophagous. This is a good sign that the fields will be protected from phytophagous insects along with all FSB. There are not many species that are tertiary consumers. Predators are represented by 1 pair of
Distribution of birds by feeding types (%): F – predators, Z – zoophages, I – entomophages, M – phytoentomophages, R – phytophages
FSB in Ukraine is created in accordance with the principles of forest typology. That is, the types of forest crops (phytocenoses) with construction, composition of tree and shrub species that best meet certain types of forest vegetation conditions (ecotope conditions) and better way get harmoniously together, supporting each other, creating a favourable environment for other biota species, as well as a sustainable, productive and durable forest ecosystem in these conditions are selected. However, as a result of land reform and changes in land ownership since the 1990s, the FSB system in Ukraine has not been properly cared for a long time. Forest belts began to be partially destroyed, inhabited by adventive species and lost the designed structure. Thus, they began to reduce the resilience, productivity and ability to perform their target – environmental and protective functions (Furdychko and Lavrov 2009; Lavrov et al. 2019). Causal–consequential relationships for all types of FSB and optimization of their systems have been shown by other researchers (Furdychko and Stadnyk 2012). It has already been proven that the completed multipurpose FSB systems, as a structural part of the multifunctional landscape, are able not only to effectively increase yields of agricultural crops, heterogeneity of the landscape and provide important ecosystem services (carbon sequestration, biodiversity conservation, soil enrichment and erosion prevention, air and water quality improvement), in general they can also provide sustainable land management (Furdychko and Stadnyk 2012; Kеdziora 2015; Holland et al. 2017; Udawatta et al. 2019; Buchanan et al. 2020). Landscape heterogeneity of habitats also enhances bird conservation and bird-mediated pest management services in intensive agriculture (Kross et al. 2016). However, we found that in the FSB of Skvyra Research Station, the species composition of nesting birds groups is much lower than in the forests of the region, although the list of dominants is similar in number (Blinkova and Shupova 2018). It is shown that wind-permeable forest belts are a nesting habitat for 18 bird species, dense – for 41, and the largest number of nesting species is characteristic of not dense oak-ash, dense ash and dense mixed forest belts (Kuzmenko 2018). Lack of undergrowth has a negative impact on birds, reproduction and feeding of which is associated with shrubs (Camprodon and Brotons 2006), i.e. for understorey birds. In the studied forest belts their share is low (6.7–18.5%). Therefore, if forest vegetation conditions allow, it is advisable to try to form multi-tiers plantations with shrub understorey. This will increase the functional structure of the forest shelter belt, the volume of its ecological niches, reduce intra- and interspecific competition of birds, will increase the number of nesting pairs per unit area of FSB. Bird nesting in agricultural fields often results in low breeding success (Sviridova et al. 2019). Dense edges in FSB from shrubs provide birds with protection from various dangers and promote realization of reproductive function (Frei et al. 2018; Zingg et al. 2018; Pringle et al. 2019). Such areas are especially relevant for ecotone birds. Dendrophiles that nest on the ground need a well-developed grass cover, the presence of wood mortality, which is the protection of nests. In the absence of woodpeckers nesting in the FSB of Skvyra Experimental Station, the lack of hollows for passive hollow-nesting birds compensates for the hanging of artificial nests (Gaychenko and Shupova 2019). In order to effectively attract insectivorous birds, it is necessary to take into account a number of ecological and ethological indicators: the area of the nesting area protected by the male or pair, which depends on the bird species, population density, nature of the area and interspecific competition.
Grass and understorey tiers, in addition to the important ecological role for birds and other animals, determine the natural regeneration of tree species, are the main centers of floral diversity and an indicator of forest ecosystems stability (Zhukova et al. 2010; Didukh 2012; Budzhak et al. 2019). The close interdependence of the tree and grass-shrub tier, their composition and structure determine the direction of the succession process in forest ecosystems (Hidding et al. 2013). In the grass cover of the studied FSB, the largest number of species has a low frequency of occurrence (till 18%) with a significant proportion of ruderals and adventive species. The problem of biological invasions is considered today as one of the threats to biodiversity, especially native species and communities (Protopopova et al. 2006; Burda and Koniakin 2019; Lavrov et al. 2019; Budzhak et al. 2019). The last stages of anthropogenic transformation of phytocenoses are characterized by the dominance of species with transitional and mixed types of strategies (Huseinova et al. 2013, Lavrov et al. 2019). The grass tier of the studied forest belts is dominated (61.5%) by species of mixed strategies.
Thus, the studied field protective forest shelter belts are significantly transformed due to long-term lack of care. This is evidenced by the structure of species in phytocenoses: the dominance of adventive species-transformers in the stand; adventive species (24.5%) and ruderants (36.5%), violation of heliophyte ratios and the presence (14.7%) of nitrophils, as well as species with a mixed life strategy (60%) in the grass tier. The latter species indicate changes in soil moisture and trophic conditions. Only in 2–7-row, wider and dense forest shelter belts, an edificatory tier with the density of canopy 0.72–0.81 and a biologically favourable environment were formed. This occurred as a result of the natural reorganization of the structure of stands by changing the weakened dominant trees with accompanying species and the invasion of other species. Narrower, wind-permeable, semi-permeable with gaps degraded forest shelter belts do not sufficiently perform environmental functions and other ecosystem services. In the studied landscape, the species composition, ecological and trophic structure of the ornithocomplex is depleted, except for only a three-tier, dense forest belt with developed shrub understorey. This is due to the lack of a complete complex of suitable and protected nesting stations. The lack of many species on nesting has a negative impact on the spectrum of bird nutrition in degraded forest shelter belts, and, accordingly, on the full protection of fields from entomo-pests. To attract insectivorous birds it is necessary to take into account their species, ecological and ethological properties, population density, the nature of habitats and features of interspecific competition.