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Carrying capacity in arid rangelands during droughts: the role of temporal and spatial thresholds

Published online by Cambridge University Press:  25 July 2016

F. Accatino*
Affiliation:
Faculty of Forest Sciences and Forest Ecology, University of Göttingen, Büsgenweg 4, Göttingen, Germany UMR SADAPT, INRA, AgroParisTech, Université Paris-Saclay, Paris 75005, France
D. Ward
Affiliation:
School of Life Sciences, University of KwaZulu Natal, Scottsville 3209, South Africa Biological Sciences, Kent State University, Kent OH44242, USA
K. Wiegand
Affiliation:
Faculty of Forest Sciences and Forest Ecology, University of Göttingen, Büsgenweg 4, Göttingen, Germany
C. De Michele
Affiliation:
Department of Civil and Environmental Engineering, Politecnico di Milano, P.zza L. Da Vinci, 32, Milano 20133, Italy
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Abstract

Assessing the carrying capacity is of primary importance in arid rangelands. This becomes even more important during droughts, when rangelands exhibit non-equilibrium dynamics, and the dynamics of livestock conditions and forage resource are decoupled. Carrying capacity is usually conceived as an equilibrium concept, that is, the consumer density that can co-exist in long-term equilibrium with the resource. As one of the first, here we address the concept of carrying capacity in systems, where there is no feedback between consumer and resource in a limited period of time. To this end, we developed an individual-based model describing the basic characteristics of a rangeland during a drought. The model represents a rangeland composed by a single water point and forage distributed all around, with livestock units moving from water to forage and vice versa, for eating and drinking. For each livestock unit we implemented an energy balance and we accounted for the gut-filling effect (i.e. only a limited amount of forage can be ingested per unit time). Our results showed that there is a temporal threshold above which livestock begin to experience energy deficit and burn fat reserves. We demonstrated that such a temporal threshold increases with the number of animals and decreases with the rangeland conditions (amount of forage). The temporal threshold corresponded to the time livestock take to consume all the forage within a certain distance from water, so that the livestock can return to water for drinking without spending more energy than they gain within a day. In this study, we highlight the importance of a time threshold in the assessment of carrying capacity in non-equilibrium conditions. Considering this time threshold could explain contrasting observations about the influence of livestock number on livestock conditions. In case of private rangelands, the herd size should be chosen so that the spatial threshold equals (or exceeds) the length of the drought.

Type
Research Article
Copyright
© The Animal Consortium 2016 

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References

Adler, PB and Hall, SA 2005. The development of forage production and utilization gradients around livestock watering points. Landscape Ecology 20, 319333.CrossRefGoogle Scholar
Ayantunde, AA, Fernández-Rivera, S, Hiernaux, PH, Van Keulen, H and Udo, HMJ 2002. Day and night grazing by cattle in the Sahel. Journal of Range Management 55, 144149.CrossRefGoogle Scholar
Bahre, CJ and Shelton, ML 1996. Rangeland destruction: cattle and drought in southeastern Arizona at the turn of the century. Journal of the Southwest 38, 122.Google Scholar
Brosh, A, Henkin, Z, Ungar, ED, Dolev, A, Orlov, A, Tehuda, Y and Aharoni, Y 2006. Energy cost of cows’ grazing activity: use of the heart rate method and the Global Positioning System for direct field estimation. Journal of Animal Science 84, 19511967.Google Scholar
Chamaillé-Jammes, S, Valeix, M and Fritz, H 2007. Managing heterogeneity in elephant distribution: interactions between elephant population density and surface-water availability. Journal of Applied Ecology 44, 625633.Google Scholar
Demment, MW and van Soest, PJ 1985. A nutritional explanation for body-size patterns of ruminant and nonruminant herbivores. American Naturalist 125, 641672.Google Scholar
Desta, S and Coppock, L 2002. Cattle population dynamics in the southern Ethiopian rangelands, 1980-97. Journal of Range Management 55, 439451.Google Scholar
Ellis, JE and Swift, DM 1988. Stability of African pastoral ecosystems: alternate paradigms and implications for development. Journal of Range Management 41, 450459.Google Scholar
Fynn, RWS and O’Connor, TG 2000. The effect of stocking rate and rainfall on rangeland dynamics and cattle performance in a semi-arid savanna, South Africa. Journal of Applied Ecology 37, 491507.Google Scholar
Gillson, L and Hoffman, MT 2007. Rangeland ecology in a changing world. Science 315, 5354.CrossRefGoogle Scholar
Grimm, V, Berger, U, Bastiansen, F, Eliassen, S, Ginot, V, Giske, J, Goss-Custard, J, Grand, T., Heinz, SK, Huse, G, Huth, A, Jepsen, JU, Jørgensen, C, Mooij, WM, Müller, B, Pe’er, G, Piou, C, Railsback, SF, Robbins, AM, Robbins, MM, Rossmanith, E, Rüger, N, Strand, E, Souissi, S, Stillman, RA, Vabø, R, Visser, U and DeAngelis, DL 2006. A standard protocol for describing individual-based and agent-based models. Ecological Modelling 198, 115126.Google Scholar
Grimm, V, Revilla, E, Berger, U, Jeltsch, F, Mooij, WM, Railsback, SF, Thulke, HH, Weiner, J, Wiegand, T and DeAngelis, DL 2005. Pattern-oriented modelling of agent-based complex systems: lessons from ecology. Science 310, 987991.CrossRefGoogle ScholarPubMed
Heidtschmidt, RK, Klement, KD and Haferkamp, MR 2005. Interactive effects of drought and grazing on Northern Great Plains rangelands. Rangelend Ecology and Management 58, 1116.Google Scholar
Illius, AW and O’Connor, TG 1999. On the relevance of nonequilibrium concepts to arid and semiarid grazing systems. Ecological Applications 9, 798813.CrossRefGoogle Scholar
Illius, AW and O’Connor, TG 2000. Resource heterogeneity and ungulate population dynamics. Oikos 89, 283294.Google Scholar
James, CD, Landsberg, J and Morton, SR 1999. Provision of watering points in the Australian arid zone: a review of effects on biota. Journal of Arid Environments 41, 87121.Google Scholar
Loza, HJ, Grant, WE, Stuth, JW and Forbes, TDA 1992. Physiologically based landscape use model for large herbivores. Ecological Modelling 61, 227252.Google Scholar
McLeod, SR 1997. Is the concept of carrying capacity useful in variable environments? Oikos 79, 529542.CrossRefGoogle Scholar
Meissner, HH, Hofmeyr, HS, van Rensburg, WJJ and Pienaar, JP 1983. Classification of livestock for realistic prediction of substitution values in terms of a biologically defined large stock unit. Technical Communication No. 175. Government Printer, Pretoria, South Africa.Google Scholar
Oba, G 2001. The effect of multiple drought on cattle in Obbu, northern Kenya. Journal of Arid Environments 49, 375386.Google Scholar
Prins, HHT and Van Langevelde, F 2008. Assembling a diet from different places. In Resource ecology: spatial and temporal dynamics of foraging (ed. HHT Prins and F Van Langevelde), pp. 129155. Springer, Dordrecht, The Netherlands.Google Scholar
Scoones, I 1995. Exploring heterogeneity: habitat use by cattle in dryland Zimbabwe. Journal of Arid Environments 29, 221237.Google Scholar
Shackleton, CM 1993. Are the communal grazing lands in need of saving? Development Southern Africa 10, 6578.Google Scholar
Smit, IPJ, Grant, CC and Devereux, BJ 2007. Do artificial waterholes influence the way herbivores use the landscape? Herbivore distribution patterns around rivers and artificial water sources in a large African savanna park. Biological Conservation 136, 8599.Google Scholar
Sullivan, S and Rohde, RF 2002. On non-equilibrium in arid and semi-arid grazing systems. Journal of Biogeography 29, 126.Google Scholar
Thurow, SF and Taylor, CA 1999. Viewpoint: the role of drought in range management. Journal of Range Management 52, 413419.CrossRefGoogle Scholar
Van Soest, PJ 1994. Nutritional ecology of the ruminant, 2nd edition. Comstock Publishing, Ithaca, NY, USA.Google Scholar
Vetter, S 2005. Rangelands at equilibrium and non-equilibrium: recent developments in the debate. Journal of Arid Environments 62, 321341.Google Scholar
Ward, D 2004. Ecological, historical and sociological perspectives of the effects of grazing on arid Namibian rangelands. In Rangelands at equilibrium and non-equilibrium: recent developments in the debate around rangeland ecology and management (ed. S Vetter), pp. 3740. Programme for Land and Agrarian Studies, Cape Town, South Africa.Google Scholar
Ward, D, Saltz, D and Ngairorue, BT 2004. Spatio-temporal rainfall variation and stock management in arid Namibia. Journal of Range Management 57, 130140.Google Scholar