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Key factors in the site selection of Rosa canina (L.) – applying the generalized additive model

100%

Guner S. T., Ozkan K., Comez A.

Polish Journal of Ecology

2011

tom 59

nr 3

Determining suitable sites for species is of great importance in the choice of plant species to be used for ecosystem restoration. The number of plant species to be used in restoration of degraded ecosystems is restricted by climate in arid and semi arid regions. Planting with economically important species in addition to ecological aspects is preferred by decision makers in Mediterrenian countries including Turkey. This study was addressed to determine the significant environmental factors influencing the distribution of dog rose hip (Rosa canina) and to obtain its distribution model. The study was carried out in an area of 26,400 km2 in The Inner Anatolia which has semiarid climate. 106 sample plots, 20 x 20 m in size, were selected from different sites with and without Rosa canina in the summer of 2007. Wilcoxon rank-sum statistic for continuous variables and Pearson Chi-square tests for categorical variables were applied. Altitude, slope degree, available water capacity, soil reaction and soil K, Ca, Mg content as well and total calcium carbonate amount as the continuous variables and northwest- northeast group of aspect, metamorphic group of bedrock as the categorical variables were determined as the significant factors influencing the presence of dog rose. Generalized Additive Model (GAM) was performed for modeling the distribution of the species. To obtain the best model, all significant environmental factors were evaluated. The best model result was obtained (training Area Under Curve (AUC) = 0.902 and cross-validation AUC = 0.841) by means of altitude, slope degree, aspect, and bedrock. Interspecific correlation analysis (ICA) was applied to define indicator species accompanying the dog rose. Dog rose distribution was positively correlated with Cistus laurifolius, Pyrus elaeagnifolia, Lonicera caucasica subsp. orientalis, Quercus vulcanica and Amelanchier rotundifolia subsp. Rotundifolia. The results obtained from this study are crucial for estimation of the suitable areas for Dog rose in restoration studies of natural ecosystems in the Mediterranean region, including Anatolia in Turkey.

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Effect of ecological factors on the zonation of wetland vegetation

100%

Hrivnak R.

Acta Societatis Botanicorum Poloniae

2005

tom 74

nr 1

The influence of some ecological factors to aquatic and marsh vegetation was studied during 1998-2000. Three basic vegetation units (Caricetum buekii, Typhetum latifoliae and Ceratophylletum submersi) and three transitional communities were defined in the belt transect, which was established along the moisture gradient. The content of available soil nutrients in individual vegetation types differed only in case of the Ceratophyllum submersum community, where a higher magnesium and nitrogen content accumulated due to specific environmental conditions. Water and marsh vegetation is usually characterised by a pronounced spatial and temporal dynamics. In the studied area, its zonation was dependent from the terrain morphology, and both depth and duration of floods. The fluctuation of ground and surface water table during a three-year period caused changes in the occurrence and cover of several species (e.g. Carex buekii, Typha latifolia, aquatic macrophytes). Pronounced changes in the cover of some species occurred even within a single vegetation season due to the long-term sink of water table below the ground surface.

Ograniczanie wyników

1 Acta Societatis Botanicorum Poloniae

1 Polish Journal of Ecology

1 Comez A.

1 Guner S. T.

1 Hrivnak R.

1 Ozkan K.

1 2011

1 2005

Wyniki wyszukiwania

Key factors in the site selection of Rosa canina (L.) – applying the generalized additive model

Effect of ecological factors on the zonation of wetland vegetation