Flora of natural pastures in the bocar area (Banat, serbia) as a bioindicator of habitat ecological conditions

Abstract

© 2014 National Centre for Agrarian Sciences. All rights reserved. Natural pastures, as unique flora and vegetation habitats, are very sensitive to environmental conditions and anthropogenic impacts; thus, understanding the relationship between plants and environmental factors is essential. Development of plants, i.e., their specific life forms, in a habitat, is affected by the climatic conditions, as well as the plant requirements with respect to other environmental factors, which are thus reliable bioindicators of environmental conditions. Studies on flora and vegetation of natural pastures, as endangered ecosystems, are thus a starting point for the assessment, monitoring and conservation of their biodiversity, aimed at ensuring their sustainable use, i.e., maintenance of their agricultural productivity. Therefore, the aim of this paper is to present the current state of the flora of the studied ecosystem, assess the prevalent environmental conditions based on the identified flora, and-via analysis of variance and correspondence analysis-determine the relationship between ecological factors and the occurrence of certain plant life forms. These findings, in addition to careful selection and planning of mowing and grazing, which should be adapted to local conditions, are expected to facilitate the natural ecosystem recovery. The studied ecosystem flora comprises 135 taxa (119 species, 5 subspecies, 4 varieties, 6 forms and 1 lusus). Based on the ecological analysis of the identified taxa, the studied ecosystem-in temperate climate conditions (Kx = 3.23), on a soil characterized by considerable degree of salinity in places (S+ = 34.92%)-is moderately moisture (F = 3.01), neutral to mildly acidic (Rx = 3.25), mesotrophic (Nx = 3.15), moderately rich in organic compounds (Hx = 2.97), moderately aerated (Dx = 4.15), and subject to a favorable light (Lx = 3.76) and thermal regimen (Tx = 3.91). The biological spectrum of the identified taxa (therophytes - 38.52%, hemicryptophytes - 37.04%, geophytes - 20.00%, chamaephytes - 3.70% and phanerophytes - 0.74%) indicates that the environmental conditions of the studied pastures are favorable for therophyte and hemicryptophyte development. Analysis of variance showed that, in the studied pastures, the development of the identified life forms is dependent on all ecological factors. The correspondence analysis between the ecological index values and the identified life forms revealed that extreme environmental conditions - very wet (F5), extremely oligotrophic (N1) and highly eutrophic (N5), humus-free (H1) or humus-rich (H5) soil, adequately aerated habitat (D2), prevalent semi-shade conditions (L2), or strong direct light (L5) - are not conductive of the development of the identified ecomorphs i.e. identified taxa.