Is the Concept of Carrying Capacity Useful in Variable Environments?

McLeod, Steven R.

doi:10.2307/3546897

Cited by 119 publications

(75 citation statements)

References 42 publications

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“…Inventories of reindeer pasture resources in all 56 reindeer herding-districts in the Finnish reindeer management area were collated for winter pastures in the period 1995-96 and for summer pastures in 1997-98 (Kumpula et al, 19971999). The main pasture types, both winter and summer pastures, were classified and mapped using Landsat-5 TM images using noteworthy field site data (see Colpaert et al, 1995;Colpaert, 1998).…”

Section: Methodsmentioning

confidence: 99%

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Productivity factors of the Finnish semi-domesticated reindeer (Rangifer t.tarandus) stock during the 1990s

Kumpula¹,

Colpaert

Nieminen³

2002

Ran

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Intensive reindeer grazing and the increase of other land use forms have caused a decline in the amount of arboreal (Alectoria, Bryoria spp.) and reindeer (Cladina spp.) lichens in the Finnish reindeer management area during the last few decades. Supplementary feeding of reindeer has increasingly compensated for the lack of natural winter fodder. The amount of the supplementary feeding and the quantity and quality of summer pastures should therefore have an increasing effect on the productivity of reindeer stock. In order to outline better the present carrying capacity problems on pastures in the Finnish reindeer management area we focused some of the most important productivity factors of Finnish reindeer stock from 1993 to 1999. The results showed that the productivity of reindeer stock in Finland was dependent especially on two main elements: amount of reindeer feeding and reindeer densities on summer pastures. Winter pastures had no clear effect on productivity when analysing the entire management area. High productivity figures in reindeer stock (calf production, carcass mass and meat production per reindeer) were reached in the management districts where winter feeding was the most abundant, reindeer densities relatively low and summer pastures abundant. An increase in reindeer density on summer pastures raised meat production per total summer pasture area but decreased carcass mass of reindeer calves and meat production per reindeer. It seems that the fundamental factor for keeping the reindeer stock productivity sustainable at a high enough level is to optimize the longterm reindeer densities on pastures. Summer pastures may gradually become a limiting factor for reindeer stock productivity in some areas if overgrazed and decreased winter pastures are only compensated for by winter feeding of reindeer.

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Section: Methodsmentioning

confidence: 99%

“…It has also been argued that the concept of carrying capacity could not be useful in stochastic environments for describing plantherbivore dynamics (e.g. McLeod, 1997). Some proposals have also been made to apply the nonequilibrium theory to pastureland management of reindeer management (Fox, 1998;Tyler, 1998;Colman, 1999).…”

Section: Introductionmentioning

confidence: 99%

Productivity factors of the Finnish semi-domesticated reindeer (Rangifer t.tarandus) stock during the 1990s

Kumpula¹,

Colpaert

Nieminen³

2002

Ran

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“…It is then important to re-define in the context of a drought the notion of carrying capacity of rangelands. Following McLeod (1997), carrying capacity could be conceived as the short-term potential livestock number that can be sustained as a function of the resource available. Such a definition of carrying capacity reframes the problem in a well-defined, time-limited context, when consumers and resources are decoupled.…”

Section: Introductionmentioning

confidence: 99%

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

Accatino

Ward

Wiegand

et al. 2017

Animal

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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.Keywords: optimal herd size, water point, energy deficit, drought, foraging ImplicationsFor addressing the carrying capacity in arid rangelands during a drought, we investigated the influence of livestock number on livestock condition during the drought accounting for livestock movement. Livestock number does not affect livestock conditions per se, it rather affects the temporal threshold after which livestock begin to experience energy deficit. If the drought is shorter than the threshold, livestock conditions are not negatively affected. If the drought exceeds the threshold, livestock experience energy deficit. The carrying capacity of a rangeland during a drought is the number of animals for which the temporal threshold equals the length of the drought.

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“…Una estimación adecuada de la K es fundamental para contribuir al mantenimiento del equilibrio entre la población de animales silvestres y la comunidad vegetal y permite evaluar el impacto de la pérdida o alteraciones de éste en el tamaño de una población (Cook y col 2007). Dicha estimación puede ser realizada utilizando diferentes modelos, dentro de los cuales se encuentran los índices de calidad del hábitat (Short 1986, Brooks 1997), a través del establecimiento del punto de equilibrio entre la tasa de crecimiento de una población y el tamaño de la misma en el área (Mandujano y col 2007) o a partir de la disponibilidad de alimentos o nutrientes específicos requeridos por una especie animal dada (McLeod 1997).…”

Section: Introductionunclassified

Incorporación de la cobertura de escape en un modelo de capacidad de carga para venado de cola blanca

et al. 2013

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Is the Concept of Carrying Capacity Useful in Variable Environments?

Cited by 119 publications

References 42 publications

Productivity factors of the Finnish semi-domesticated reindeer (Rangifer t.tarandus) stock during the 1990s

Productivity factors of the Finnish semi-domesticated reindeer (Rangifer t.tarandus) stock during the 1990s

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

Incorporación de la cobertura de escape en un modelo de capacidad de carga para venado de cola blanca

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