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D.A. Belov
Russia, Moscow state university of forest
DYNAMICS OF
URBAN MINER-INSECTS IN STANDS OF MOSCOW
AND THEIR
FORECAST
One of the main groups in insect fauna in the city are
foliage and needle mining insect. Unlike in the rural forests, where their
damage is felt much less, in stands of the city their economic value increases,
and it is possible to name a few specific species that do most damage.
Mining insects in town stands of Moscow currently includes 96 species,
amongst which are the most representative families of leaf miners (Gracilariidae) – 29 species and small moths (Nepticulidae) – 27 species.
Miners can be found in stands of all types, but especially where the
stress conditions of the urban environment reduce the tree's vitality, e.g. on
streets. The most packed present complex a miners in the town park forests and
parks, where there is a most variety of types of wood plants, are denominated
many of layer valance, variety of microclimatic
conditions and in least degrees is polluted surround ambience.
The correlation of the number of species in stands of Moscow with the
location in the city is as follows: in park forests, parks and large green
territory – 86 species; in stands in yards, on boulevards and gardens, in
near-home complex street boarding – 59 species; in street stands –
39 species.
Amongst those miners most common in the city are the poplar leaf miner (Lithocolletis populifoliella
Tr.), the linden leaf miner (Lithocolletis issikii Kumata) and larch casebearer moth (Coleophora sibiricella Flkw.). These types
are capable to produce massive population growth, that
can be categorised by the intervals of mass reproduction
and the duration of the calamity caused by mass populations.
For the conditions in Moscow, the phenology,
particularities of behaviour, condition and wintering
were studied, and the population dynamics (e.g. deathrate,
spectral composition and role of parasites) were examinde.
Leaf miners in the city have increased their spectrum of places of wintering to
the account of dwelling and nondwelling buildings and
have acquired an ability to produce double generations in one year.
Their spreading within the city is accelerated by breezes along roads
and in building space. As lock-and-key factors of death-rate at a period of
high ascents of the number in their populations often emerges a competition of
maggots, intensified under uneven and sprained summers and under the unstable
weather conditions at a period from Mid May until the beginning of June. Beside
larch casebearer by the significant factor of
death-rate emerge insects-eater birds, destroy part wintering in case
caterpillars. Composition their parasites in conditions of city includes from 5
(larch casebearer) before 7 (poplar leaf miner)
species. It is interesting to note that the parasites are both preying on
miners and other species – Chrysoharis sp.
Forster and Cirrospilus pictus
Nees. (Eulophidae, Chalcidoidea). The mortality of miners through parasites in
all years of observing varied from 5,8 to 11,3 %,
which means that they are the second largest single influence on miners in the
city.
Species of miners m stands of city trees form different types of centres, ranging from small scale to large centres, covering in separate years nearly all stands within the city, to other yean>, when the damage
is only local or even only in individual trees.
Based on knowledge of the spectral composition, biology, ecology and
particularities of the number and mass reproduction of miners and me
distribution of their centres, a control strategy was
designed for methods of long-term and short-term forecast. For the long-term
forecast, the number of populations of poplar leaf miner and larch casebearer is calculated, and then test models, based on
given permanent observing with using the factors of duplicating of populations,
are denominated in me logarithmic form. For the short-term forecast, optimum
conditions are modeled and set against the available biomass that is available
as potential feeding for the insects.
Печатная версия тезосов опубликована:
Abstrakts of the Conference «Urban Greenspace in the 21st Century – Urban Greening as a Development Tool». Book 1. – St. Petersburg, State Forest Technical Academy, 2001. – P. 52 – 54.
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