Plant Species and Functional Types’ Diversity in Relation to Grazing in Arid and Semi-arid Rangelands, Khabr National Park, Iran

Document Type: Research and Full Length Article


1 Gorgan University of Agricultural Sciences and Natural Resources, Gorgan

2 Gorgan University of Agricultural Sciences and Natural Resources, Gorgan,


In arid and semi-arid rangelands, grazing as one of the natural or human induced processes has direct and indirect effects on structure and dynamics of plant community and ecosystems. A study was done to analyze the effects of grazing on plant species diversity and Plant Functional Types‘ (PFTs) diversity of arid and semi-arid rangelands. We analyzed plant richness and diversity data from 75 sampling plots located in five bioclimatic zones of Khabr National Park containing a total of 73 plant species. Ward's hierarchical clustering was then used to cluster all plant species into eight PFTs according to the chosen traits. For each site, grazing intensity was estimated in three classes (low grazing, medium and high grazing intensities). We found that as grazing intensity increased, total species richness and diversity were decreased. Considering PFTs as total showed the same pattern for species; however, each PFT diversity and richness didn‘t display a significant different response to grazing. Looking at each PFT relative cover change in different grazing intensities showed that PFT1 and PFT8 were grazing sensitivities while PFT6 and PFT7 benefited from grazing and their relative cover increased consistently in response to the increased grazing intensity. PFT3 and PFT4 had the highest relative cover rates in moderately grazed areas. PFT2 and PFT5 had a complicated response to grazing and their relative cover was the minimum at moderately grazed sits. This finding may imply that grazing has completely negative impacts on the community structure and it seems that it reduces plant species and functional types‘ diversity and richness. It can be also concluded that the analyses on PFTs level possibly give more insight into the grazing response of plant community in arid and semi-arid rangelands than those on species level but there is a need for further studies.


Anderson, P. M. L. and Hoffman, M. T., 2011. Grazing response in the vegetation communities of the Kamiesberg, South Africa: Adopting plant functional type approach. Jour. Arid Environment, 75:255-264.

Bergmeier, E. and Dimopoulos, P., 2003. The vegetation of islets in the Aegean and the relation between the occurrence of islet specialists, island size, and grazing. Phytocoenologia, 33: 447–474.

Cornelissen, J. H. C., Lavorel, S., Garnier, E., Díaz, S., Buchmann, N., Gurvich, D. E., Reich, P. B., ter Steege, H., Morgan, H. D., van der Heijden, M. G. A., Pausas, J. G. and Poorter, H., 2003. A handbook of protocols for standardized and easy measurement of plant functional traits worldwide. Australian Jour. Botany, 51: 335-380.

Davari, N., Jouri, M. H., Ariapour, A., 2011. Comparison of measurement indices of diversity, richness, dominance, and evenness in rangeland ecosystem (Case study: Javaherdeh-Ramesar). Jour. Rangeland Science, 2(1): 389-398. (In Persian).

Diaz, S., Briske, D. and McIntyre, S., 2002. Range management and plant functional types. In: Hodkingson, K., Grice, A. C., Global rangelands: progress and prospects, CAB International, Wallingford, UK, 81-100.

Diaz, S., Lavorel, S., McIntyre, S., Falczuk, V., Casanoves, F., Milchunas, D.G., Skarpe, C., Rusch, G., Sternberg, M., Noy-meir, I., Landsberg, J., Zhang, W., Clark, H. and Campbell, B. D., 2007. Plant trait responses to grazing – a global synthesis. Global Change Biology, 13: 313–341.

Diaz, S., Noy-Meir, I. and Cabido, M., 2001. Can grazing response of herbaceous plants be predicted from simple vegetative traits? Jour. Applied Ecology, 38: 497–508.

Dyksterhuis, E. J., 1958. Ecological principles in range evaluation. Bot. Rev., 24: 253-272.

Forouzeh, M. R. and Sharafatmandrad, M., 2012. The effect of water spreading system on the functionality of rangeland ecosystems. Jour. Arid Land, 4(3): 292-299. (In Persian).

Frank, D. A., McNaughton, S. J. and Tracy, B. F., 1998. The ecology of the earth’s grazing ecosystems. Bioscience, 48(7): 513–521.


Gitay, H. and Noble, I. R., 1997. What are functional types and how should we seek them? In: Smith, T. M., Shugart, H. H., Woodward, F. I., (ed). Plant functional types: Their relevance to ecosystem properties and global change. Cambridge University Press, London, 3–19. UK.

Gondard, H., Sandrine, J., Aronson, J. and Lavorel, S., 2003. Plant functional types: a promising tool for management and restoration of degraded lands. Applied Vegetation Science, 6: 223-234.

Grime, J. P., Hodgson, J. G., Hunt, R., Thompson, K., Hendry, G. A. F., Campbell, B. D., Jalili, A., Hillier, S. H., Diaz, S. and Burke, M. J. M., 1997. Functional types: testing the concept in Northern England? In: Smith, T. M., Shugart, H. H., Woodward, F. I. (ed), Plant functional types: Their relevance to ecosystem properties and global change. Cambridge University Press, London, 122–152.

Hayes, G. F. and Holl, K. D., 2003. Cattle grazing impacts on annual forbs and vegetation composition of me sic grasslands in California. Conservation Biology, 17: 1694–1702.

Heitschmidt, R. K., Dowhower, S. L. and Walker, J. W., 1987. Some effects of rotational grazing treatment on quantity and quality of available forage and amount of ground litter. Jour. Range Management, 40: 318–321.

Hickman, K. R., Hartnett, D. C., Cochran, R. C. and Owensby, E. C., 2004. Grazing management effects on plant species diversity in tall grass prairie. Jour. Range Management, 57: 58–65.

Hobbs, R. J. and Huenneke, L. F., 1992. Disturbance, diversity and invasion: implications for conservation. Conservation Biology, 6: 324–337.

Holechek, J. I. and Galt, D., 2000. Grazing intensity guidelines. Rangelands, 22(3): 11-14.

Irannejad Parizi, M. H., 2000. Assessing structure and diversity of vegetation with emphasis on arid and semi-arid woodland habitats of Khabr National Park. Ph.D thesis in Forestry, University of Tehran, Iran. (In Persian).

Irannejad Parizi, M. H., Sanei Shariat Panahi, M., Zobeiri, M. and Marvi Mohajer, M. R., 2001. A floristic and phytogeographycal investigation of Khabr National Park and Rouchun Wildlife Refuge. Iranian Jour. Natural Resources, 54(2): 111-129. (In Persian).

Jauffret, S. and Lavorel, S., 2003. Are plant functional types relevant to describe degradation in arid, southern Tunisian steppes? Jour. Vegetation Science, 14: 399–408.

Jouri, M. H., Patil, D., Gavali, R. S., Safaian, N. and Askarizadeh, D., 2011. Assessment of health conditions of mountain rangeland ecosystem using species diversity and richness indices, (Case study: Central Alborz, Iran). Jour. Rangeland Science, 2(1): 341-353.

Lavorel, S., McIntyre, S., Landsberg, J. and Forbes, T. D. A., 1997. Plant functional classifications: from general groups to specific groups based on response to disturbance. Trends in Ecology and Evolution, 12: 474–478.

Magurran, A. E., 1988. Ecological diversity and its measurement. Princeton Univ. Press, Princeton, New Jersey, USA.

McIntyre, S., Lavorel, S., Landsberg, J. and Forbes, T. D. A., 1999. Disturbance response in vegetation towards a global perspective on functional traits. Jour. Vegetation Science, 10: 621–630.

Mesdaghi, M., 2011. Statistical and regression methods “An applied approach to plant and animal sciences”. Imam Reza University Press, Mashhad, Iran. (In Persian).

Mitchell, R. J., Auld, M. H. D., Le Duc, M. G. and Robert, M. H., 2000. Ecosystem stability and resilience: a review of their relevance for the conservation management of lowland heaths. Prospect. Plant Ecol. Evolve. Syst., 3: 142-160.

Mitchell, R. J., Marrs, R. H., Le Duc, M. G. and Auld, M. H. D., 1999. A study of the restoration of heathland on successional sites in Dorset, Southern England: changes in vegetation and soil chemical properties. Jour. Applied Ecology, 36: 770-783.

Mwendera, E. J., Saleem, M. A. M. and Woldu, Z., 1997. Vegetation response to cattle grazing in the Ethiopian Highlands. Agric Ecosys Environ, 64: 43–51.

Navarro, T., Alados, B. and Cabezudo, B., 2006. Changes in plant functional types in response to goat and sheep grazing in two semi-arid shrub lands of SE Spain. Jour. Arid Environment, 64: 298-322.

Noble, I. R. and Gitay, H., 1996. A functional classification for predicting the dynamics of landscapes. Jour. Vegetation Science, 7: 329-336.

Noy-Meir, I., 1993. Compensating growth of grazed plants and its relevance to the use of rangelands. Ecological Applications, 3(1): 32–34.

Papanikolaou, A. D., Fyllas, A. D., Dimitrakopoulos, P. G., Kallimanis, A. S. and Pantis, J. D., 2011. Grazing effects on plant functional group diversity in Mediterranean shrublands. Biodiversity and Conservation, 20(12): 2831-2843.

Perevolotsky, A. and Seligman, N. G., 1998. Role of grazing in Mediterranean rangeland ecosystems. Bioscience, 48: 1007–1017.

Ritchie, M. E. and Tilman, D., 1995. Responses of legumes to herbivores and nutrients during succession on a nitrogen-poor soil. Ecology, 76(8): 2648–2655.

Rutherford, M. C., O’Callaghan, M. O., Hurford, J. L. and Mack, F., 1995. Realized niche spaces and functional types: a framework for prediction of compositional change. Jour. Biogeography, 22: 523-531.

Safford, H. D. and Harrison, S. P., 2001. Grazing and substrate interact to affect native vs. exotic diversity in roadside grasslands. Ecological Applications, 11:1112–1122.

Sharafatmandrad, M., Mesdaghi, M., Bahremand, A. and Barani, H., 2010. The role of litter in rainfall interception and maintenance of superficial soil water content in an arid rangeland in Khabr National Park in South-Eastern Iran. Arid Land Research and Management, 24(3): 213-222. (In Persian).

Smith, T. M., Shugart, H. H. and Woodward, F. I. E., 1997. Plant functional types. Cambridge University Press, Cambridge, UK.

Solbrig, O. T., 1993. Plant traits and adaptive strategies: their role in ecosystem function. In: Schulze, E.D. and Mooney, H.A. (ed.). Biodiversity and ecosystem function. Ecological Studies, 99: 97–116.

Valone, T. J., Meyer, M., Brown, J. H. and Chew, R. M., 2002. Timescale of perennial grass recovery in decertified arid grasslands following livestock removal. Conservation Biology, 16: 995–1002.

Walker, B. H. and Noy-Meir, I., 1982. Aspects of the stability and resilience of savanna ecosystems. In: Huntley, B. J., Walker, B. H., Ecology of Tropical Savannas, Springer, Berlin, 556–590.

Ward, D., 2006. Long-term effects of herbivory on plant diversity and functional types in arid ecosystems. In: Danell, K., Bergström, R., Duncan, P., Pastor, J., Large herbivore ecology, ecosystem dynamics and conservation. Cambridge University Press, 142-169. UK.

Weiher, E., van der Werf, A., Thompson, K., Roderick, M., Garnier, E. and Eriksson, O., 1999. Challenging Theophrastus: a common core list of plant traits for functional ecology. Jour. Vegetation Science, 10: 609–620.

Wesuls, D., Oldeland, J. and Dray, S., 2012. Disentangling plant trait responses to livestock grazing from spatio-temporal variation the partial RLQ approach. Jour. Vegetation Science, 23: 98–113.

Woodward, F. I. and Cramer, W., 1996. Plant functional types and climatic changes: Introduction. Jour. Vegetation Science, 7: 306–308.