Effect of fire intensity on the grass and bush components of the Eastern Cape thornveld

Trollope, W.S.W.; Tainton, N.M.

doi:10.1080/02566702.1986.9648030

Cited by 58 publications

(66 citation statements)

References 3 publications

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“…This additional set of PAs was selected to enlarge the range of ecological domains considered in the analysis, more particularly the guineo-congolian and guineo-congolia/sudanian ecoregions, and to include some PAs where we knew that a conservation project was in place, such as the Garamba and Zakouma national parks respectively in D.R.C and Chad. (1) Ecoregion Area (ha) (2) Region 1 inside (3) 25 km (4) mainly for ecosystem protection and recreation, designated to (a) protect the ecological integrity of one or more ecosystems and (b) exclude exploitation or occupation inimical to the purposes of designation of the area. IV: Protected area managed mainly for conservation through management intervention, so as to ensure the maintenance of habitats and/or to meet the requirements of specific species.…”

Section: Open Accessmentioning

confidence: 99%

“…The temporal aspects of the fire regimes have been largely studied to support ecological assessments of the savanna ecosystem in the Southern Africa region [3][4][5][6][7][8][9] as well as in West Africa [10][11][12][13][14]. The combine effects of fire frequency and burning intensity have a direct impact on the respective proportions of grass, shrub and tree vegetation.…”

Section: Open Accessmentioning

confidence: 99%

“…2 data source: [2]. 3 surface of the protected area. 4 surface of a 25 km buffer zone around the protected area.…”

Section: Open Accessmentioning

confidence: 99%

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Interannual Changes of Fire Activity in the Protected Areas of the SUN Network and Other Parks and Reserves of the West and Central Africa Region Derived from MODIS Observations

Grégoire

Simonetti

2010

Remote Sensing

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Time series of fire occurrence, derived from MODIS data, have been used to characterise the spatio-temporal distribution of fire events during the 2004-2009 period in 17 protected areas (PAs) of West and Central Africa, with particular attention to those of the SUN network in Senegal, Burkina Faso, Benin and Niger. The temporal distribution of the fire activity and the number of fire occurences are quite different inside the PAs and in their surrounding area. A progressive increase of the length of the burning season is observed in the West Africa PAs. Quantitatively, the general trend over the last five years is an increase of the fire density (+22%) inside the PAs and a decrease (−27%) outside. The results indicate that the capacity of the PAs to maintain the biological diversity of the region is probably decreasing due to the combined effects of the anthropic pressure inside the PAs and of an on-going isolation process.

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Section: Open Accessmentioning

confidence: 99%

Section: Open Accessmentioning

confidence: 99%

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Interannual Changes of Fire Activity in the Protected Areas of the SUN Network and Other Parks and Reserves of the West and Central Africa Region Derived from MODIS Observations

Grégoire

Simonetti

2010

Remote Sensing

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“…Savannahs with mean annual precipitation levels of around 650mm or below are reasonably stable, but tend to change towards forest above this level (unless other disturbance processes allow a mix of grass and trees to be maintained) [1,14]. Other potential drivers include fire [16][17][18][19][20][21][22][23], disturbance by megaherbivores, particularly elephant (Loxodonta africana) [4,19,[24][25][26][27], grazing by domestic herbivores [28], scale-dependent interactions between climate, fire and herbivory [17,[29][30][31][32], and increasing CO 2 fertilization [5,9,10,17,[33][34][35][36][37][38][39][40][41][42][43]. The vulnerability of a region to changes in the tree-grass balance of savannas will likely depend on the prevailing land use history, the environmental setting, and the functional traits of woody plants that govern their responsiveness to both local and global drivers [12].…”

Section: Introductionmentioning

confidence: 99%

Scrubbing Up: Multi-Scale Investigation of Woody Encroachment in a Southern African Savannah

et al. 2017

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Changes in the extent of woody vegetation represent a major conservation question in many savannah systems around the globe. To address the problem of the current lack of broad-scale cost-effective tools for land cover monitoring in complex savannah environments, we use a multi-scale approach to quantifying vegetation change in Kruger National Park (KNP), South Africa. We test whether medium spatial resolution satellite data (Landsat, existing back to the 1970s), which have pixel sizes larger than typical vegetation patches, can nevertheless capture the thematic detail required to detect woody encroachment in savannahs. We quantify vegetation change over a 13-year period in KNP, examine the changes that have occurred, assess the drivers of these changes, and compare appropriate remote sensing data sources for monitoring change. We generate land cover maps for three areas of southern KNP using very high resolution (VHR) and medium resolution satellite sensor imagery from February 2001 to 2014. Considerable land cover change has occurred, with large increases in shrubs replacing both trees and grassland. Examination of exclosure areas and potential environmental driver data suggests two mechanisms: elephant herbivory removing trees and at least one separate mechanism responsible for conversion of grassland to shrubs, theorised to be increasing atmospheric CO 2 . Thus, the combination of these mechanisms causes the novel two-directional shrub encroachment that we observe (tree loss and grassland conversion). Multi-scale comparison of classifications indicates that although spatial detail is lost when using medium resolution rather than VHR imagery for land cover classification (e.g., Landsat imagery cannot readily distinguish between tree and shrub classes, while VHR imagery can), the thematic detail contained within both VHR and medium resolution classifications is remarkably congruent. This suggests that medium resolution imagery contains sufficient thematic information for most broad-scale land cover monitoring requirements in heterogeneous savannahs, while having the benefits of being cost-free and providing a longer historical archive of data than VHR sources. We conclude that monitoring of broad-scale land cover change using remote sensing has considerable potential as a cost-effective tool for both better informing land management practitioners, and for monitoring the future landscape-scale impacts of management policies in savannahs.

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“…Researchers in southern Africa have amassed a large body of information on fire effects on savanna vegetation (e.g. Phillips, 1930;Acocks, 1953;Trapnell, 1959;Trollope and Tainton, 1986;Bond, 1997). Savanna vegetation dynamics are inherently unstable (Norton-Griffiths, 1979;McNaughton, 1984;Trollope, 1984;Westoby et al, 1989) and respond to periodic yet spatially and temporally unpredictable climate, fire, grazing, and browsing events (Bond and van Wilgen, 1996).…”

Section: Introductionmentioning

confidence: 99%

Trends in fire patterns in a southern African savanna under alternative land use practices

Hudak

Fairbanks

Brockett

2004

Agriculture, Ecosystems & Environment

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Climate, topography, vegetation and land use interact to influence fire regimes. Variable fire regimes may promote landscape heterogeneity, diversification in vegetation pattern and biotic diversity. The objective was to compare effects of alternative land use practices on landscape heterogeneity. Patch characteristics of fire scars were measured from 21 annual burn maps produced from 1972 to 2001 Landsat imagery. Trends in fire patterns under alternative land use practices were compared across a 250,000 ha savanna in southern Africa partitioned into three land use zones. Zone 1, Madikwe Game Reserve (MGR), has had mostly prescribed fires since 1993. Zone 2, cattle farms near MGR in South Africa (SAF), has experienced occasional fires. Zone 3, communal grazing lands in neighboring Botswana (BOT), has had the fewest fires. Cattle ranching was the predominant land use throughout the study area until 1992, when land use switched to conservation and eco-tourism in MGR. Sixteen landscape metrics were applied to this data set to uncover trends in the patch characteristics of the fire scars. A principal components analysis (PCA) reduced the dimensionality of the results so trends in the 10 most important size, shape, and proximity metrics could be better interpreted. The PCA results showed that more burning over time in MGR, and to a lesser extent in SAF, increased patch size, size variability, shape complexity and proximity, while fire exclusion in BOT produced no change or decreasing trends. We tested for significant differences in these metrics between the three land use zones and between two periods, 1972-1992 and 1993-2001. Most patch characteristics in MGR and SAF differed significantly from those in BOT, especially during the latter period, while between MGR and SAF they did not. Patch area, shape complexity and core area increased significantly between periods in MGR, while patch size, size variability and core area increased significantly between periods in SAF. In BOT, no patch characteristics changed significantly between periods. Within the time span analyzed for the study area, we conclude that increased fire occurrence promoted landscape heterogeneity while fire exclusion did not. Published by Elsevier B.V.

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Effect of fire intensity on the grass and bush components of the Eastern Cape thornveld

Cited by 58 publications

References 3 publications

Interannual Changes of Fire Activity in the Protected Areas of the SUN Network and Other Parks and Reserves of the West and Central Africa Region Derived from MODIS Observations

Interannual Changes of Fire Activity in the Protected Areas of the SUN Network and Other Parks and Reserves of the West and Central Africa Region Derived from MODIS Observations

Scrubbing Up: Multi-Scale Investigation of Woody Encroachment in a Southern African Savannah

Trends in fire patterns in a southern African savanna under alternative land use practices

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