БҚМУ Хабаршы №1-2019ж.
Introduction. The term “biological diversity” is capacious and the variety of
forms of lifecan be analyzed in various ways. Apart from the Whittaker’s [1; 2]
concepts of alpha-, beta- and gamma-diversityusually expressed by the number of
species (thus related to species diversity) it can be studied on the main three levels:
species diversity, genetic diversity and ecosystem diversity [3]. Leaving aside
describing of the current and past diversity which could be used to predict its changes
in the future, the knowledge on the biodiversity is very important when its links with
e.g. climatic changes, agriculture or methods of biotechnology are considered and the
benefits are regarded [3; 4]. Apart from the main ecological value of biological
diversity expressed in the preamble to Convention on Biological Diversity [5] itsall
other values (genetic, social, economic, scientific, educational, cultural, recreational
and aesthetic) are crucial in the scope of responsibility for biodiversity conservation
and sustainable use. One of the programs of UN within the CBD concerns the soil
biodiversity in which the mites (Arachnida, Acari) are extremely important because of
their role in the matter and energy flow in the ecosystems. Mites are not the only forms
of life in the soil however are the most abundant arthropods in this part of ecosystem
and significantly contribute to the ecosystem services provided by the soil biodiversity.
There are about 55,000 species of mites and ticks known (including some fossil
taxa of Acari) in two superorders: Parasitiformes and Acariformes. In soil environment
two groups usually predominate namely Mesostigmata (=Gamasida) that as order is
included in Parasitiformes and Oribatida included as suborder in acariform order
Sarcoptiformes [6] Currently there are 11,424 species of Mesostigmata and 16,412
species of Sarcoptiformes known including 16,305 species of Oribatida (in recent form
including Astigmata). Despite the total mite species known constitute about half of
known arachnids and is greater than e.g. spider species diversity (43,579 species) it is
commonly accepted that mite diversity is highly underestimated and probably consist,
according to various estimates, from half a million to even about million of species and
one of the important reasons of such underestimation is cryptic speciation [7; 8; 9]. On
the contrary to other arachnids which are mainly predators, mites are very diverse in
terms of their food base, as the predation is only one of the main feeding strategies in
mites also including parasitism, phytophagy, mycophagy and saprophagy [7]. However
the size of an individual mite is usually less than one millimeter, their crucial role in
various types of ecosystems is the result of their abundance and also reflected in their
position within the food web.
Mites in humidity/habitat gradient. Humidity is presumably the main, apart from
temperature, environmental factor that shape the diversity of communities. The
influence of above-mentioned factors is either direct (through the ecological tolerance
of an individual) or indirect (through the influence on soil formation processes also
shaped by other climatic factors, soil chemical properties etc.).
The influence of humidity level was studied so far e.g. in specific habitats of
Bagno Stawek Reserve (Zaborski Landscape Park, Tuchola Forest, N Poland). In
various pine forests [Leucobryo-Pinetum (fresh pine forest), Molinio-Pinetum (moist
pine forest), Vacciniouliginosi-Pinetum (wet pine forest)] and within the fen
(Caricetum lasiocarpae) humidity shaped the local biodiversity of mesostigmatidmites
[10]. In general the increase of habitat humidity caused drop in total abundance of
Mesostigmata as well as decrease of species number. Moreover, in the most humid fen
habitat the lowest species diversity (H’) and the lowest community eveness (J’) were
recorded (Table 1).
Table 1 – General Mesostigmata community parameters (A – abundance in
thousands of individuals per square meter, S – number of species, H’ – Shannon-
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