scholarly journals The Effect of Surface Fire in Savannah Systems in the Kruger National Park (KNP), South Africa, on the Backscatter of C-Band Sentinel-1 Images

Fire ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 37
Author(s):  
Renaud Mathieu ◽  
Russell Main ◽  
David P. Roy ◽  
Laven Naidoo ◽  
Hannah Yang
Keyword(s):  
South Africa ◽  
National Park ◽  
Fire Effects ◽  
Kruger National Park ◽  
Fuel Load ◽  
Burned Area ◽  
Surface Fire ◽  
Early Season ◽  
Surface Fires ◽  
Effect Of Surface

Savannahs are mixed woody-grass communities where low-intensity surface fires are common, affecting mostly the grass layer and rarely damaging trees. We investigated the effect of surface fires in a savannah system in the Kruger National Park, South Africa, on the backscatter of synthetic aperture radar (SAR) C-band Sentinel-1A images. Pre-fire and post-fire dual polarized (VH, VV) C-band backscatter values were examined for 30 burn events. For all events, a systematic backscatter decrease from pre-fire to post-fire conditions was observed, with mean backscatter decreases of 1.61 dB and 0.99 dB for VH and VV, respectively. A total of 90% and 75% of the burn events showed a decrease in VH and VV backscatter greater than 0.43 dB, the overall absolute radiometric of Sentinel-1A products. The VH data were, overall, 1.7 times more sensitive to surface fire effects than the VV data. C-band data are likely sensitive to a reduction in grass biomass typical of surface fires, as well as in grass/soil moisture levels. Early season fires had higher backscatter decreases due to greater early season moisture conditions. For region with more than 30% woody cover, the effect of fire on the C-band backscatter was reduced. Denser woody communities tend to produce lower grass fuel load and less intense surface fires, and limit the penetration of C-band microwaves to the ground where most savannah fires and associated effects occur. This research provides evidence that C-band space-borne SAR is sensitive to the effects of surface-level fires in southern African savannahs. The unique availability of frequent and spatially detailed C-band data from the Sentinel-1 SAR constellation provide new opportunities for burned area mapping and systematic monitoring in savannahs systems, for instance, for fine-scale fire propagation studies.

scholarly journals The spatial dimensions of Savanna fire ecology in Kruger National Park, South Africa

2015 ◽  
Author(s):  
◽  
Daniel Godwin
Keyword(s):  
South Africa ◽  
National Park ◽  
Fire Severity ◽  
Kruger National Park ◽  
Tree Cover ◽  
Annual Precipitation ◽  
Fuel Load ◽  
Fire Intensity ◽  
Mean Annual Precipitation ◽  
Woody Cover

Savannas are thought to be bistable with forests potentially occurring above [about]650 mm / yr of Mean Annual Precipitation (MAP) due to the limiting effects of fire on tree cover. This is predicated on two assumptions: 1) fires increasingly limit woody cover in more mesic (> 650 MAP) savannas and 2) increasing tree cover produces feedbacks that reduce fire intensity. These assumptions are investigated in a spatially explicit framework. We use Kruger National Park (KNP), South Africa as our study system, in part due to the wide range of frequency of fires, the large variation in natural communities and rainfall, and the large body of previous research for comparisons and modeling efforts. To investigate whether tree cover produces feedbacks on fire intensity, we measured fire behavior as a function of grass fuel load and woody cover in experimental burns within KNP. We found weak but positive relationships (not negative, as assumed) between woody cover and fire intensity, independent of grass fuel load, and no relationship between tree cover and grass fuel load. At a landscape scale, we modeled the factors predicted to drive fire severity in KNP. We observed that fireline intensity is a strong predictor of many estimations of fire severity in small fires, but across larger fires, rainfall and woody cover likewise can predict impacts on herbaceous consumption and woody cover, respectively. Lastly, to investigate whether trees escape fire less often in more mesic savannas, we used a stochastic model parameterized with real data. After a review of published growth rates, we modeled fire escape probability using mean annual precipitation, fire frequency, and fireline intensity values across KNP. When accounting for species turnover across rainfall gradients, we found a nearly flat relationship between the probability of individuals escaping fire and rainfall. Our research challenges two key assumptions for fire-mediated bistability of mesic savannas.

scholarly journals Ecological suitability modeling for anthrax in the Kruger National Park, South Africa

PLoS ONE ◽  
2018 ◽  
Vol 13 (1) ◽  
pp. e0191704 ◽  
Author(s):  
Pieter Johan Steenkamp ◽  
Henriette van Heerden ◽  
Ockert Louis van Schalkwyk
Keyword(s):  
South Africa ◽  
National Park ◽  
Kruger National Park ◽  
Ecological Suitability

scholarly journals Visitation patterns of principal species of the insect-complex at carcasses in the Kruger National Park

Koedoe ◽  
1981 ◽  
Vol 24 (1) ◽  
Author(s):  
L.E.O Braack
Keyword(s):  
South Africa ◽  
National Park ◽  
Kruger National Park ◽  
Physical Attributes ◽  
Principal Species ◽  
Aepyceros Melampus

Two full-grown impala rams Aepyceros melampus were shot on 1978.01.07 in the Pafuri area of the Kruger National Park, Republic of South Africa. The carcasses were placed in enclosures 2,7 km apart and used to monitor the visitation patterns of insects. Collections of insects were made at four-hourly intervals for the first six days after placement of the carcasses, and thereafter every six hours up to the eleventh and final day. A figure is given to describe changes in the physical attributes of the carcasses through time. Twelve figures depict the patterns of arrival of insects at the carrion habitat. Species from the following families are represented: Cleridae, Dermestidae, Histeridae, Scarabaeidae, Silphidae, Staphylinidae, Trogidae (Coleoptera); Calliphoridae, Muscidae, Piophilidae, Sepsidae (Diptera); Diapriidae and Formicidae (Hymenoptera). The results indicate that species have distinctive periods of abundance and presents an overall picture of insect succession at carrion.

The importance of the Kruger National Park For bird conservation in the Republic of South Africa

Koedoe ◽  
1980 ◽  
Vol 23 (1) ◽  
Author(s):  
A. C Kemp
Keyword(s):  
South Africa ◽  
National Park ◽  
Kruger National Park ◽  
Tropical Species ◽  
Conservation Priorities ◽  
Bird Conservation ◽  
The Republic ◽  
Wetland Habitats

One hundred and two species of birds that are thought to be vulnerable in South Africa have been reported from or are likely to occur within the Kruger National Park. These species are considered in relation to their distribution and status in South Africa and the neigbouring countries. The following are suggested as conservation priorities for birds in the Park: 1. Re-establish the extinct Yellow-billed Oxpecker. 2. Investigate the suite of large carnivorous and scavenging birds that have declined over much of their range elsewhere in South Africa. 3. Investigate the species associated with riparian and wetland habitats in the Park. 4. Investigate the tropical species that are confined to the Park within South Africa.

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