Dr. Biol. Sci Yu.N. Karpun, V.A. Kunina

The State Research Institution All–Russian Scientific and Research Institute of Floriculture and Subtropical Crops of the Russian Academy of Agricultural Sciences, c. Sochi, Russia

Problems of self-seeding plants dispersal in the structure

of Sochi urban green spaces

Abstract. The paper considers topical issues of the role played by self-seeding plants in the structure of green spaces of resort town Sochi. It informs about the quantitative composition of these crops in the surveyed areas, subdivided by major bio-economic groups in the region. It presents the results of the floristic analysis of self-seeding plants, dominated by crops introduced from East Asia - 16 genera that originate from similar climatic regions and are well adapted in Sochi conditions. The paper also brings the analysis of the way the crops disperse their seeds, revealing the most effective. In most cases, the range of self-seeding plants is quite ornamental and organically fits into the structure of urban green areas.

Key words: self-seeding, tree examination, life form, urban spaces, floristic analysis.

INTRODUCTION

Sochi resort is located in a unique climate zone, which can be characterized as a transition between the moderately warm and humid subtropical [9]. As a result, introduction possibilities of the region are the most favorable in Russia. A large number of different crops, including woody plants are cultivated as ornamental plants. According to various estimates [2, 4, 5, 8], cultural dendroflora of the region has four to five thousand crops in the rank of species and intraspecific taxa.

The study of this plant diversity, which has a determining influence on the physiognomic appearance of the existing urbanized ecocenosis, represents a great scientific interest, interfaced with a number of problems [1, 3]. One of such problems is a quantitative and qualitative analysis of woody components from the local urban ecocenosis due to the geographical features of the region as well as the structural features of the city, which stretches along the coast for 140 kilometers.

SUBJECTS AND METHODS

Tree examination of all woody crops growing here can take several years and require the involvement of a large number of dendrologists, apart from considerable financial costs for this kind of inventory. It seems that to resolve some of the issues of quantitative and qualitative analysis of local dendroflora it would be possible to apply the method of sampling, which is based on the selection of small, but specific areas of urban spaces.

Such objects may be several of the streets in the city centre, some of them located parallel to the coastline of the Black Sea, while others - perpendicular. These streets are characterized by both intense and limited traffic. In addition, they should be extended enough. Primorskaya, Kurortnyi prospect, Rose and Gagarina streets correspond to these conditions and reflect the specificity of urban greening in Sochi.

RESULTS AND DISCUSSION

In April-May 2014, we carried out tree examination in these streets within ten meters of the roadside. In the course of this inventory we were taking into account the data about the revealed crop composition, determining life form and age of the plants, their size and state. Later, these lists underwent extensive versatile statistical processing which resulted in preliminary conclusions about the state of urban tree plantations in Sochi.

This paper considers the role played by self-seeding plants identified during the examination in the structure of urban green spaces. They are variously presented and make up almost one-tenth of all the recorded plants (Table 1).

Table 1.

Representation of self-seeding woody plants in the structure of the examined sites

Name of crop groups	Number sp., pcs.	Including
		planted sp., pcs./%	self-seeding sp., pcs./%
all in all accounted (154/328)	12584	11446 / 91,0	1138 / 9,0
including coniferous crops (20/55)	692	692 / 100	–
from them woody crops (12/29)	331	331 / 100	–
bushy crops (8/26)	361	361 / 100	–
including deciduous crops (117/231)	9618	8945 / 93,0	673 / 7,0
from them woody crops (41/76)	1255	881 / 70,2	374 / 29,8
evergreen woody crops (11/18)	569	429 / 75,4	140 / 24,6
semi-evergreen woody crops (1/1)	1	1	–
Leaves-shading woody crops (29/57)	685	451 / 65,8	234 / 34,2
from them shrub crops (66/137)	8 175	7 891 / 96,5	284 / 3,5
evergreen shrub crops (38/89)	6 603	6 490 / 98,3	113 / 1,7
deciduous shrub crops (28/48)	1 572	1 401 / 89,1	171 / 10,9
from them vine crops (10/18)	188	173 / 92,0	15 / 8,0
evergreen vine crops (5/11)	140	126 / 90,0	14 / 10,0
deciduous vine crops (5/7)	48	47 / 97,9	1 / 2,1
including tree-like crops (12/36)	1996	1531 / 76,7	465 / 23,3
from them palms (6/22)	1246	781 / 62,7	465 / 37,3
bamboos (2/4)	431	431	–
rosette plants (4/10)	319	319	–
including ground covering plants (5/6)	278	278	–

Note: representation of the genera / representation of crops are indicated in brackets after the names of crop groups

It should be noted that we have not identified any self-seeding plants among conifers, bamboos and rosette ground covering plants that are older than five years. The majority of the accounted plants (37.3%) were observed in the palm group; mainly these are plants belonging to the genus Trachycarpus, mostly common to the culture conditions of the region. This is partly explained by a high degree of acclimatization in Trachycarpus fortunei, as well as by psycho-emotional perception of palm trees as ornamental plants. Locals retain maximum self-seeding, giving the opportunity to achieve a significant age and size.

Among deciduous plants of self-seeding origin, mostly represented are the following: a group of deciduous trees (34.2%, 19 crops from 29), evergreen trees (24, 6%, 6 crops from 11) and deciduous shrubs and bushy trees (10.9%, 8 crops from 28). Among leaves-shading trees, numerically predominate Ailanthus altissima - 57 sp. and Acer pseudoplatanus - 48 sp.; among evergreen - Ligustrum lucidum - 106 sp. and Eriobotrya japonica - 22 sp.; among deciduous shrubs - Hibiscus syriacus - 69 sp. and Ficus carica - 41 sp.

We should also note that the majority of self-seeding plants have an increased ornamentality (Hibiscus syriacus, Robinia pseudoacacia, Philadelphus coronaries et al.) or represent a utilitarian value (Cerasus avium, Laurus nobilis, Ficus carica, etc.).

The results of the floristic analysis of self-seeding plants represent a sufficient interest, since they correspond to prevailing ideas [2, 8] about the adaptation ability of introduced woody plants in the given region (Table 2).

Table 2.

Floristic analysis of self-seeding woody crops in the structure

of the examined sites

Floristic regions	Number of genera, pcs.	Number of crops, pcs.	Number of specimen, pcs.
Eurasia	14	14	164
including aboriginal crops	13	13	153
Mediterranean	4	4	99
North America, including Mexico	5	5	49
East Asia, including the Himalayas	16	19	826
Total crops	39	42	1138

According to the results of our study, including the whole region, crops introduced from East Asia have a leading position. This is due to the climatic parameters of Russian humid subtropics, which are identical to those in central China, and some parts of Japan [2, 4, 8]. From this floristic region viable self-seeding component is formed from 19 crops belonging to 16 genera, representing 72.6% of all investigated plants. The leaders in this floral group are Trachycarpus fortunei (462 sp.), Ligustrum lucidum (162 sp.) and Ailanthus altissima (57 sp.).

On the second place, there are some crops of southern Eurasian origin essentially conceding quantitatively (164 sp.) and slightly taxonomically (163 sp.). Maximally presented are Acer pseudoplatanus (48 sp.), Corylus avellana (26 sp.) and Ulmus grabra (19 sp.).

Self-seeding plants from the Mediterranean are significantly fewer, despite the fact that the region of Sochi is close to this floristic area on a number of climate aspects (4 crops, 99 sp.) [6]. In this crop group, Laurus nobilis (55 sp.) and Ficus carica (41 sp.) are noticeable.

Among the crops of self-seeding origin, North America is represented to a lesser extent – by 5 crops and 49 sp, among which we can find Carya alba (17 sp.), Acer negundo (15 sp.) and Robinia pseudoacacia (14 sp.).

It should be taken into account that all these floristic regions are in the northern hemisphere. The representatives of this Hemisphere do not form a viable self-seeding, although we have noted them in the number of crops occurring.

Essential is also an analysis of self-seeding crops by the way they disperse their seeds, which is sometimes crucial for their mass distribution (Table 3).

Table 3.

Analysis of self-seeding crops by the way they disperse their seeds

Ways of seed dispersal	Number of genera, pcs.	Number of crops, pcs.
By birds	13	16
Under the weight	11	12
By wind	7	9
By human	5	5

Table 3 shows that the method of seed dispersal by herbivorous birds is the most productive - 16 crops (Trachycarpus fortunei, Ligustrum lucidum, Laurus nobilis et al.). There are fewer crops dispersed by baric way when inedible and quite heavy seeds fall and germinate near mother plants - 12 crops (Hibiscus syriacus, Carya alba, Robinia pseudoacacia et al.). 9 crops disperse by wind distributed seeds (Ailanthus altissima, Acer pseudoplatanus, Ulmus grabra et al.). Only 5 crops disperse with the help of a human (Corylus avellana, Eriobotrya japonica, Diospyros kaki, etc.).

Most often, self-seeding appears near the base of lightweight fences, hedges and house territories between the sidewalk and tall buildings, less frequently – near the groups of shrubs and roadside slopes.

CONCLUSION

Summarizing the results of a comprehensive analysis conducted, we should note the following:

- In most cases, self-seeding plants are quite ornamental and organically fit into the structure of urban green areas.

- Viable self-seeding trees occur the most frequently (evergreen, deciduous), including deciduous shrubs and bushy trees. The leader among self-seeding plants is Trachycarpus, which accounts for over 40% of all identified plants.

- The crops from the regions of East Asia (mainly central and Western China) are floristically more likely to form a viable self-seeding; it is more than two-thirds of all accounted plants.

- The way of dispersal by herbivorous birds is predominant. In the context of the region it is predominantly a blackbird (a big bird with a fairly dense population).

- Sustainable self-seeding is often fixed near the base of lightweight fences and hedges.

The results we have obtained in the study will be useful for optimizing crop composition and improving the structure of urban green areas of Sochi resort, as well as for design changes in urban development practice

References:

1. Ginkul S.G. Introduction and naturalization of plants in the humid subtropics of the USSR [Text] / S.G. Ginkul. // News of Batum. bot. garden. - 1936 - Vol. 1. - P. 3-51.

2. Goltsberg I.A. Global agro-climatic analogues of subtropical zone of the USSR [Text] / I.A. Goltsberg. // Materials on the agro-climatic zoning in subtropics of the USSR. - L .: TSUEGMS, 1936. - P. 251-254.

3. Karpun Yu.N. Treasures of Sochi parks. [Text] / Yu.N. Karpun. - Sochi: SBSK, 1998. - 172 p.

4. Karpun Yu.N. Subtropical ornamental dendrology [Text] / Yu.N. Karpun. - St. Petersburg: Publishing House "VVM", 2010. - 580 p.

5. Catalog of cultivated woody plants of Russia [Text] / edited by Yu.N. Karpun. - Sochi-Petrozavodsk: SBSK, 1999. - 173 p.

6. Kuznetsov S.I. Elements of the Mediterranean region in the Western Caucasus [Text] / S.I. Kuznetsov. - St. Petersburg, 1891. - 190 p.

7. Mosiyash A.S. Agroclimatic characterization of Big Sochi [Text] / A.S. Mosiyash, A.M. Lugavtsov. - Rostov/Don: State Meteo Publ., 1967. - 152 p.

8. Pilipenko F.S. Foreign trees and shrubs on the Black Sea coast of the Caucasus [Text] / F.S. Pilipenko. - L .: Nauka, 1978. - 293 p.

9. Selyaninov G.T. Agro-climatic zones and subtropical regions of the USSR [Text] / Selyaninov G.T. // Materials on the agro-climatic zoning in subtropics of the USSR. - L .: Publishing House TSUEGMS, 1936. - P. 234-250.