THE EFFECTS OF LONG-TERM EXCLOSURES ON RANGE PLANTS IN THE CENTRAL ANATOLIAN REGION OF TURKEY.

Authors: FIRINCIOGLU, H - CENTRAL RES. INST. TURKEY; Seefeldt, Steven; SAHIN, BILAL - GAZI UNIV. TURKEY

Submitted to: Environmental Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/3/2006
Publication Date: 3/20/2007
Citation: Firincioglu, H.K., Seefeldt, S.S., Sahin, B. 2007. The effects of long-term exclosures on range plants in the central Anatolian region of Turkey. Environmental Management. 39(3):326-337.

Interpretive Summary: Over the last fifty years, almost half of the steppe rangeland in the Central Anatolian Region of Turkey (CAR) has been converted to cropping land without an equivalent reduction in grazing animals. This has led to heavy grazing pressure on rangeland vegetation. Using pastures that were free of grazing for the last 27 years a comparison of plant diversity and cover was determined on the grazed and ungrazed pastures. The ungrazed plots had 113 plant species whereas the grazed plots had 81. There were only 31 plant species common to the two sites. Forb species were reduced in the grazed pastures. Not all the additional species in the ungrazed pastures were desirable for grazing. Our study led to four broad generalizations about the current grazing regime and long-term exclosures in the steppe rangelands of CAR: (1) the exclosure increased species richness and diversity, (2) continuous grazing is eliminating some plant species from plant community, (3) complete protection from grazing for a prolonged period of time after long history of grazing disturbance will not led to a considerable increase in the cover of desirable plant species, (4) a controlled grazing system such as deferred grazing rather than complete exclosure or continuous grazing might foster secondary succession.

Technical Abstract: Over the last fifty years, almost half of the steppe rangeland in the Central Anatolian Region of Turkey (CAR) has been converted to cropping land without an equivalent reduction in grazing animals. This has led to heavy grazing pressure on rangeland vegetation. A study was initiated in June 2003 using 6 multiscale Modified-Whittaker plots to determine differences in plant diversity between areas that have not been grazed in 27 years with neighboring grazed plant communities. A total of 113 plant species was identified in the study area with the ungrazed plots containing 32 more than the grazed plots. The major species were Astragalus acicularis, Bromus tomentellus, Festuca valesiaca, Genista albida, Globularia orientalis, Poa bulbosa and Thymus spyleus ssp rosulans. A particular characteristic of steppe vegetation in the CAR is the presence of a few dominant species in each functional group (forbs, grasses and shrubs). Thus, variation in plant cover of the functional groups reflected patterns of variation of the dominant species. Grazing impacts on forbs were more pronounced than for grasses and shrubs. There was only a 37% overlap in plant species between the two treatments. Our study led to four broad generalizations about the current grazing regime and long-term exclosures in the steppe rangelands of CAR: (1) the exclosure increased species richness and diversity, (2) continuous grazing is eliminating some plant species from plant community, (3) complete protection from grazing for a prolonged period of time after long history of grazing disturbance will not led to a considerable increase in the cover of desirable plant species, (4) a controlled grazing system such as deferred grazing rather than complete exclosure or continuous grazing might foster secondary succession.