A comparison of some range condition assessment techniques used in southern African grasslands

Hurt, C.R.; Bosch, Ockie J.H.

doi:10.1080/02566702.1991.9648280

Cited by 21 publications

(9 citation statements)

References 22 publications

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“…First is the lingering spectre of classifications of range condition based on identifying the ‘successional status’ of species with reference to the perceived climax community or ‘benchmark’ for a given area. As pointed out by Hurt & Bosch (1991, p. 131), and as a result of the influences in the 1930 and 1940s of state officials well‐versed in the orthodoxies of North American and European ecology (Beinart, 1996, pp. 57–59; Scoones, 1996, pp.…”

Section: Species Compositionmentioning

confidence: 99%

“…35–38), it is conventional within southern African rangeland ecology to define species as Decreasers and Increasers of various classes based on their successional response to disturbance from a ‘climax community’ caused by grazing. Proportional species composition is then used ‘…as a basis for calculating some form of range conditional assessment’ (Hurt & Bosch, 1991, p. 131; also see De Klerk, 1947, pp. 352–353; Foran et al ., 1978; Tainton et al ., 1980; Vorster, 1982, p. 84; Bosch & Janse Van Rensburg, 1987; Danckwerts & Stuart‐Hill, 1988; Barnes, 1990a,b; Trollope, 1990; Trollope et al ., 1990; Bosch & Gauch, 1991; Bosch & Theunissen, 1992; Strohbach, 1992; Joubert, 1997).…”

Section: Species Compositionmentioning

confidence: 99%

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On non‐equilibrium in arid and semi‐arid grazing systems

Sullivan¹,

Rohde²

2002

Journal of Biogeography

200

148

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A critical comment on A. Illius and T. G. O'Connor (1999) On the relevance of non-equilibrium concepts to arid and semi-arid grazing systems. Ecological Applications, 9, 798-813.A debate in ecology rages over the sources and types of dynamic behaviour driving ecological systems. Drylands have become a particular focus of this debate. In these environments extreme and unpredictable variability in rainfall are considered to confer non-equilibrium dynamics by continually disrupting the tight consumer-resource relations otherwise considered to pull a system towards equilibrium. This implies that livestock grazing in drylands, widely thought to cause degradation and ÔdesertificationÕ through bad management practices leading to overstocking, might not be causing irreversible ecological change through over-use of vegetation. An article recently published in Ecological Applications (Illius & O'Connor, 1999), however, argues that variability in arid and semi-arid grazing systems is not the outcome of qualitatively different dynamical behaviour, and that livestock do cause negative change through ÔnormalÕ density-dependent relations. The authors maintain that these operate primarily in key resource areas and during drought periods.We contest these arguments on several grounds: that key terms are poorly applied in ways which suggest inconsistencies in the internal logic of the arguments; that the paper is unjustifiably selective in the choice and interpretation of ÔevidenceÕ on which it builds; and that the authors do not engage critically with the crucial policy implications of the debate, particularly as they relate to pastoral landuse by African herders in areas under communal tenure and management. We do not suggest that degradation never occurs in arid and semi-arid rangelands, but that Illius and O'Connor's analysis of the mechanisms via which this might take place is misleading and at times, we feel, theoretically bizarre. In particular, we suggest that drought periods may be the times when density-dependent mechanisms are least likely to occur and that key resource areas exist because of ungrazeable reserves which effectively cannot be degraded, although subject to heavy grazing. We also attempt to draw out the theoretical implications of attributing change caused by biotic-abiotic effects to biotic-biotic interactions. We contend that non-equilibrium concepts remain crucial for both natural and social science approaches to understanding dryland environments and their multiple, dynamic uses by pastoralists.Illius and O'Connor's critique of non-equilibrium concepts as a means for understanding ecosystem behaviour in African drylands seeks to address a deepening conceptual fault line separating factions of the rangeland science and livestock development community. Epitomizing one side of this divide are understandings of semi-arid and arid environments in terms of relationships between their biotic components, emphasizing the potential for grazing by domestic livestock to perturb the ÔsystemÕ from a knowable and desi...

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Section: Species Compositionmentioning

confidence: 99%

Section: Species Compositionmentioning

confidence: 99%

On non‐equilibrium in arid and semi‐arid grazing systems

Sullivan¹,

Rohde²

2002

Journal of Biogeography

200

148

View full text Add to dashboard Cite

show abstract

“…An understanding of the processes of degradation provides a sound basis for the ecological interpretation of condition assessments (Bosch and Kellner 1991). Hurt and Bosch (1991) stated that sample site location and site recovery potential appeared along a gradient degradation when grazing gradients were constructed through ordination studies.…”

Section: Discussionmentioning

confidence: 99%

“…The exclusive use of indicator species can simplify monitoring, especially in communitybased monitoring programs, where land managers themselves are involved with condition assessments to determine the outcomes of their management programs (Hurt and Bosch 1991). Gibson and Bosch (1996) cited several historical vegetation studies from different areas, as follows: the response of species to various grazing intensities (Cockayne 1920), the history of vegetation change in the grasslands (Connor 1964;Connor and MacRae 1969), the understanding of vegetation change, and interpretation of some of the changes within a historical framework of land use (Hughes 1975;O'Connor 1982O'Connor , 1986Scott et al 1988;O'Connor and Harris 1991;Mark 1994).…”

Section: Introductionmentioning

confidence: 99%

The determination of indicator plant species for steppe rangelands of Nevşehir Province in Turkey

Ünal¹,

Mutlu²,

Urla³

et al. 2013

Turk J Agric For

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“…The recent development of the research on range ecosystem are based on using the two important tools of monitoring and assessing practices (Hurt and Bosch 1991;Gibson and Bosch 1996;Herrick et al 2006).…”

Section: Introductionmentioning

confidence: 99%

The Use of Indicator Species and Ecological Degradation Model for Condition Assessment in Turkey

Ünal¹,

Şahin²,

Urla³

et al. 2017

Tarla Bitkileri Merkez Araştırma Enstitüsü Dergisi

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Monitoring of vegetation change is essential to detect good management practices for the sustainable use of natural rangeland resources. An understanding of how the existing species in vegetation react to management methods is important for decision makers. For this reason, the vegetation changes should be determined by suitable techniques. The multivariate analysis as Detrended Correspondence Analysis and Principal Components Analysis was highly examined and its results were easily interpreted to draw conclusions. A relatively homogenous data set first, a matrix of 221 species and 44 sample sites in the province of Yozgat in the Central Anatolia Region in year 2010, was used by detrended correspondence analysis (DCA). The effects of environmental variation was minimized by this method (DCA) so that the major pattern of vegetation composition change was explained by grazing impact. Principal components analysis was performed to detect the distribution of sites along the first axis, and the distance off the x-axis. Fifteen species out of the promising 89 plant species were found to be indicators. These indicator species should be benefited for the vegetation change status and sustainable rangeland management under semiarid rangeland conditions. The fifteen plant species and bare ground showed clear responses along the first axis (grazing impact gradient), and became abundant over certain ranges of this axis.

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A comparison of some range condition assessment techniques used in southern African grasslands

Cited by 21 publications

References 22 publications

On non‐equilibrium in arid and semi‐arid grazing systems

On non‐equilibrium in arid and semi‐arid grazing systems

The determination of indicator plant species for steppe rangelands of Nevşehir Province in Turkey

The Use of Indicator Species and Ecological Degradation Model for Condition Assessment in Turkey

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