scholarly journals Influence of fire frequency on Colophospermum mopane and Combretum apiculatum woodland structure and composition in northern Gonarezhou National Park, Zimbabwe

Koedoe ◽  
2009 ◽  
Vol 51 (1) ◽  
Author(s):  
Edson Gandiwa ◽  
Shakkie Kativu
Keyword(s):  
Plant Height ◽  
Woody Plants ◽  
National Park ◽  
Fire Management ◽  
Fire Frequency ◽  
Annual Rainfall ◽  
Frequency Effects ◽  
In Fire ◽  
Mopane Woodland ◽  
Combretum Apiculatum

We investigated the long-term effects of fire frequency on Colophospermum mopane and Combretum apiculatum woodland structure and composition in northern Gonarezhou National Park (GNP), Zimbabwe. Fire frequency was categorised as high (every 1–2 years), medium (every 3–4 years) and low (every 5–6 years). The following variables were measured or recorded: plant height, species name, canopy depth and diameter, basal circumference, number of stems per plant, plant status (dead or alive) and number of woody plants in a plot. There was a positive correlation (r = 0.55, P = 0.0007) between annual area burnt (total from January to December) and annual rainfall (average over two rain stations per rain year, July to June) between 1972 and 2005. A total of 64 woody species were recorded from C. mopane and C. apiculatum woodlands. Mean plant height increased from 4.5 to 8.2 meters in C. mopane woodland and from 4.5 to 5.1 meters in C. apiculatum woodland in areas subjected to high and low fire frequencies. In C. mopane woodland, low fire frequency was characterised by a significantly low density of woody plants (P < 0.001), however, with a significantly high mean basal area (P < 0.001). Fire frequency had no significant effect on species diversity (P > 0.05). Our results suggest that C. mopane and C. apiculatum woodlands are in a state of structural transformation. Fire frequency effects, however, appear to be woodland specific. Fire management strategies in GNP should take into consideration annual rainfall and the different vegetation types.Conservation implication: This study provides valuable information on fire frequency effects on woody vegetation in northern GNP, which can be used in fire management programmes for the park. The positive relationship between annual rainfall and annual area burnt emphasises the need for wildlife managers to consider annual rainfall in fire management.

scholarly journals The impact of the provision of water for game on the woody vegetation around a dam in the Kruger National Park

Koedoe ◽  
1991 ◽  
Vol 34 (2) ◽  
Author(s):  
I. Thrash ◽  
P.J. Nel ◽  
G.K. Theron ◽  
J. Du P. Bothma
Keyword(s):  
Relative Density ◽  
Woody Plants ◽  
National Park ◽  
Dominant Species ◽  
Canopy Cover ◽  
Kruger National Park ◽  
Woody Vegetation ◽  
Colophospermum Mopane ◽  
The Impact ◽  
Combretum Apiculatum

Quantitative inventory surveys were done on the woody vegetation in permanently marked plots at distance intervals from the Wik-en-Weeg Dam, Kruger National Park, in 1973. The surveys were repeated in 1990 so that changes in the community composition, the density and the canopy cover and the survival of the woody vegetation could be determined in relation to distance from the dam. Relationships with distance from the dam were shown for the relative density ofCombretumapiculatum in all height classes, the relative canopy cover of the second height class of woody plants, the relative canopy cover of C. apiculatum plants, the survival of all height classes of woody plants and the survival of C. apiculatum and Colophospermum mopane plants. It was concluded that the provision of water for game at the Wik-en-Weeg Dam had an impact on the woody vegetation in the vicinity. The relationships of parameters of the two dominant species, Combretum apiculatum and Colophospermum mopane, with distance from the dam were compared. Combretum apiculatum parameters were more sensitive to impact associated with the dam than those of Colophospermum mopane.

Soil clay content and fire frequency affect clustering in trees in South African savannas

2008 ◽  
Vol 24 (3) ◽  
pp. 269-279 ◽  
Author(s):  
Thomas A. Groen ◽  
Frank van Langevelde ◽  
Claudius A.D.M. van de Vijver ◽  
Navashni Govender ◽  
Herbert H.T. Prins
Keyword(s):  
South African ◽  
Tree Species ◽  
National Park ◽  
Clay Content ◽  
Abundant Species ◽  
Fire Frequency ◽  
Kruger National Park ◽  
Annual Rainfall ◽  
Soil Clay Content ◽  
The Impact

Abstract:In this paper, we investigate which factors determine tree clustering in Southern African savannas. This was tested by measuring clustering of trees using the T-squared sampling method in plots of the Kruger National Park experimental burning programme in South Africa. Fire return interval is the main treatment in these plots, but also several auxiliary determining parameters like clay content in the soil, diameter of tree canopies, understorey composition, tree species diversity and average annual rainfall were measured while sampling. In the Kruger National Park 48 plots distributed over four different landscape types and with three different burning treatments (never, once every 3 y and annually) were sampled. First, we related the clustering of trees to these environmental variables. When looking at the most abundant species in each plot, the analysis revealed that clustering is mainly correlated with clay content in the soil. This analysis also showed that fire frequency had a positive effect on the clustering of tree species that are not very abundant. We suggest that less abundant species might be less resistant to fire and therefore adopt a mechanism of clustering to exclude grass fires under their canopy. Finally, we tested the effect of clustering on the impact of fire on trees by analysing the relationship between the distance of a tree to its nearest neighbour and its canopy diameter. We found that clustering reduces the damaging effect of fire on trees. Our study contributes to understanding of savanna functioning by showing which processes are relevant in the distribution of savanna trees.

scholarly journals An assessment of the implementation and outcomes of recent changes to fire management in the Kruger National Park

Koedoe ◽  
2008 ◽  
Vol 50 (1) ◽  
Author(s):  
Brian W. Van Wilgen ◽  
Navashni Govender ◽  
Sandra MacFadyen
Keyword(s):  
National Park ◽  
Fire Management ◽  
Fire Regime ◽  
Kruger National Park ◽  
Fire Intensity ◽  
Target Area ◽  
Large Fires ◽  
Sufficient Degree ◽  
Burnt Areas ◽  
In Fire

This paper reviews recent changes in fire management in the Kruger National Park, and assesses the resulting fire patterns against thresholds of potential concern. In 2002, a lightning-driven approach was replaced by an approach that combined point ignitions with unplanned and lightning fires. The approach aimed to burn an annual target area, determined by rainfall and fuel conditions, in point-ignition fires of different sizes. Most of the original fire-related thresholds of potential concern (TPCs) were incorporated into the new approach. The annual target area to be burnt ranged from 12 to 24% of the park between 2002 and 2006. The total area burnt generally exceeded the targets each year, and management fires accounted for less than half of the total area burnt. The fire regime was dominated by very large fires (> 5 000 ha) which accounted for 77% of the total area burnt. New TPCs were developed to assess whether the fire regime encompassed a sufficient degree of variability, in terms of fire intensity and the spatial distribution of burnt areas. After assessment and adjustment, it appears that these TPCs have not yet been exceeded. The point-ignition approach, and its evaluation in terms of variability and heterogeneity, is based on the untested assumption that a diverse fire regime will promote biodiversity. This assumption needs to be critically assessed. We recommend that the practice of point ignitions be continued, but that greater efforts be made to burn larger areas earlier in the season to reduce large and intense dry-season fires.

Response of a shrubland mammal and reptile community to a history of landscape-scale wildfire

2015 ◽  
Vol 24 (4) ◽  
pp. 534 ◽  
Author(s):  
Tim S. Doherty ◽  
Robert A. Davis ◽  
Eddie J. B. van Etten ◽  
Neil Collier ◽  
Josef Krawiec
Keyword(s):  
Fire History ◽  
Fire Management ◽  
Local Level ◽  
Fire Frequency ◽  
Specific Information ◽  
Fire Exclusion ◽  
Management Approaches ◽  
Species Specific ◽  
Taxonomic Groups ◽  
In Fire

Fire plays a strong role in structuring fauna communities and the habitat available to them in fire-prone regions. Human-mediated increases in fire frequency and intensity threaten many animal species and understanding how these species respond to fire history and its associated effect on vegetation is essential to effective biodiversity management. We used a shrubland mammal and reptile community in semiarid south-western Australia as a model to investigate interactions between fire history, habitat structure and fauna habitat use. Of the 15 species analysed, five were most abundant in recently burnt habitat (8–13 years since last fire), four were most abundant in long unburnt areas (25–50 years) and six showed no response to fire history. Fauna responses to fire history were divergent both within and across taxonomic groups. Fire management that homogenises large areas of habitat through either fire exclusion or frequent burning may threaten species due to these diverse requirements, so careful management of fire may be needed to maximise habitat suitability across the landscape. When establishing fire management plans, we recommend that land managers exercise caution in adopting species-specific information from different locations and broad vegetation types. Information on animal responses to fire is best gained through experimental and adaptive management approaches at the local level.

scholarly journals Paleoecological Investigation of Vegetation, Climate and Fire History in, and Adjacent to, Kootenay National Park, Southeastern British Columbia, Canada

2022 ◽  
Vol 9 ◽  
Author(s):  
Thomas J. Rodengen ◽  
Marlow G. Pellatt ◽  
Karen E. Kohfeld
Keyword(s):  
British Columbia ◽  
National Park ◽  
Fire History ◽  
Accumulation Rate ◽  
Fire Frequency ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Carbon Accumulation ◽  
Early Holocene ◽  
In Fire

Paleoecological investigation of two montane lakes in the Kootenay region of southeast British Columbia, Canada, reveal changes in vegetation in response to climate and fire throughout the Holocene. Pollen, charcoal, and lake sediment carbon accumulation rate analyses show seven distinct zones at Marion Lake, presently in the subalpine Engelmann Spruce-Subalpine Fir (ESSF) biogeoclimatic (BEC) zone of Kootenay Valley, British Columbia. Comparison of these records to nearby Dog Lake of Kootenay National Park of Canada in the Montane Spruce (MS) BEC zone of Kootenay Valley, British Columbia reveals unique responses of ecosystems in topographically complex regions. The two most dramatic shifts in vegetation at Marion Lake occur firstly in the early Holocene/late Pleistocene in ML Zone 3 (11,010–10,180 cal. yr. B.P.) possibly reflecting Younger Dryas Chronozone cooling followed by early Holocene xerothermic warming noted by the increased presence of the dry adapted conifer, Douglas-fir (Pseudotsuga menziesii) and increasing fire frequency. The second most prominent change occurred at the transition from ML Zone 5 through 6a (∼2,500 cal. yr. B.P.). This zone transitions from a warmer to a cooler/wetter climate as indicated by the increase in western hemlock (Tsuga heterophylla) and subsequent drop in fire frequency. The overall cooling trend and reduction in fire frequency appears to have occurred ∼700 years later than at Dog Lake (∼43 km to the south and 80 m lower in elevation), resulting in a closed montane spruce forest, whereas Marion Lake developed into a subalpine ecosystem. The temporal and ecological differences between the two study sites likely reflects the particular climate threshold needed to move these ecosystems from developed forests to subalpine conditions, as well as local site climate and fire conditions. These paleoecological records indicate future warming may result in the MS transitioning into an Interior Douglas Fir (IDF) dominated landscape, while the ESSF may become more forested, similar to the modern MS, or develop into a grassland-like landscape dependent on fire frequency. These results indicate that climate and disturbance over a regional area can dictate very different localized vegetative states. Local management implications of these dynamic landscapes will need to understand how ecosystems respond to climate and disturbance at the local or ecosystem/habitat scale.

Variations in fire frequency and climate over the past 17 000 yr in central Yellowstone National Park

Geology ◽  
2000 ◽  
Vol 28 (3) ◽  
pp. 211 ◽  
Author(s):  
Sarah H. Millspaugh ◽  
Cathy Whitlock ◽  
Patrick J. Bartlein
Keyword(s):  
Yellowstone National Park ◽  
National Park ◽  
Fire Frequency ◽  
The Past ◽  
In Fire

Variations in fire frequency and climate over the past 17 000 yr in central Yellowstone National Park

Geology ◽  
2000 ◽  
Vol 28 (3) ◽  
pp. 211-214 ◽  
Author(s):  
Sarah H. Millspaugh ◽  
Cathy Whitlock ◽  
Patrick J. Bartlein
Keyword(s):  
Yellowstone National Park ◽  
National Park ◽  
Fire Frequency ◽  
The Past ◽  
In Fire

Recovery of treeless subalpine vegetation in Kosciuszko National Park after the landscape-scale fire of 2003

2015 ◽  
Vol 63 (7) ◽  
pp. 597 ◽  
Author(s):  
K. L. McDougall ◽  
N. G. Walsh ◽  
G. T. Wright
Keyword(s):  
Plant Communities ◽  
National Park ◽  
Fire Frequency ◽  
Landscape Scale ◽  
Vegetation Types ◽  
Sensitive Species ◽  
Compositional Changes ◽  
Regeneration Strategies ◽  
Fire Intervals ◽  
In Fire

The vegetation of fire-prone landscapes is influenced by the frequency, severity, seasonality, return interval and stochastic patterning of fire as well as the responses of its component species. An expected increase in fire frequency and severity in association with global warming may result in compositional changes within, and spatial reorganisation of, plant communities; indeed, some plant communities may even face extinction. Vegetation dominated by fire-sensitive species may be most vulnerable to change in fire frequency. A landscape-scale fire in Kosciuszko National Park in 2003 provided an opportunity to compare recovery in vegetation dominated by resprouters and fire-sensitive, obligate seeders. We hypothesised that if plant assemblages had failed to recover after 10 years in terms of species richness and cover they would have been dominated by seeder species pre-fire. After 10 years, two of the six vegetation types investigated had recovered and these were indeed dominated by resprouter species. Two groundwater-dependent vegetation types (one resprouter-dominated and one dominated by fire-sensitive species) were close to recovery. However, the other two types, non-groundwater-dependent shrublands dominated by both seeder and resprouter species, were still far from recovery at that time, with shrub cover reduced and grass cover increased. The likelihood of recovery after 10 years therefore does not appear to be solely a consequence of the regeneration strategies of the dominant species. Post-fire environmental factors (e.g. grazing, disease, climate) may be just as important as regeneration strategies in determining recovery time. Because not all vegetation had recovered after 10 years, prediction of minimum tolerable fire intervals at a landscape scale is impossible at this time. Future fire management needs to be adaptive, taking into account post-fire influences, rather than prescriptive.

Comment—A re-examination of the effects of fire suppression in the boreal forest

2001 ◽  
Vol 31 (8) ◽  
pp. 1462-1466 ◽  
Author(s):  
K Miyanishi ◽  
E A Johnson
Keyword(s):  
Boreal Forest ◽  
Fire Management ◽  
Fire Suppression ◽  
Fire Frequency ◽  
Stand Age ◽  
Reliable Estimate ◽  
Fire Size ◽  
Fire Cycle ◽  
Large Fires ◽  
In Fire

A report by Ward and Tithecott (P.C. Ward and A.G. Tithecott. 1993. Ontario Ministry of Natural Resources, Aviation, Flood and Fire Management Branch, Publ. 305.) is frequently cited in the literature as providing evidence of the effects of fire suppression on the boreal forest. The study is based on 15 years of fire data and stand age data from Ontario, Canada. A re-examination of this report reveals serious flaws that invalidate the conclusions regarding effects of fire suppression on fire size and fire frequency. The fire-size data from the unprotected zone are censored in the small size classes because of detection resolution, invalidating comparisons of shapes of the distributions between the protected and unprotected zones. Use of different plotting scales gives the false appearance of large differences in the number of large fires between the two zones. Stand age data are used to show a change in fire frequency in the 20th century, and this change is attributed to fire suppression. However, no evidence is presented to conclude that this change in fire frequency is attributable to fire suppression and not to climate change. The estimate of the current fire cycle is based on too short a record to give a reliable estimate given the variation in annual area burned. Therefore, this report does not present sound evidence of fire suppression effects and should not be cited as such.

Does fire limit tree biomass in Australian savannas?

2015 ◽  
Vol 24 (1) ◽  
pp. 1 ◽  
Author(s):  
Brett P. Murphy ◽  
Adam C. Liedloff ◽  
Garry D. Cook
Keyword(s):  
Conceptual Model ◽  
Upper Bound ◽  
Water Availability ◽  
Fire Management ◽  
Fire Frequency ◽  
Tropical Savannas ◽  
Tree Biomass ◽  
Tree Layer ◽  
Recruitment Bottleneck ◽  
In Fire

Processes allowing coexistence of trees and grasses in tropical savannas have long intrigued ecologists. Early theories focused on climatic controls, but a conceptual model has emerged suggesting that savanna trees are subject to a fire-mediated recruitment bottleneck, with frequent fires preventing recruitment of saplings into the tree layer and maintaining biomass well below its climate-determined upper bound. We propose that this conceptual model has been overemphasised in northern Australia, where tree abundance is more strongly controlled by water availability. The dominant trees, eucalypts, have a remarkable capacity to grow through the ‘fire trap’ to reach fire-resistant sizes. This fire tolerance makes eucalypts relatively unresponsive to management-imposed reductions in fire frequency and intensity. Other trees in these savannas are typically more fire sensitive and respond positively to such management. There are suggestions that savanna fire management could lead to increases in woody biomass, but we contend that if tree biomass is strongly limited by water availability, then potential increases in tree biomass are relatively limited, at least in relation to the dominant eucalypt component. There is potential to increase the biomass of the more fire-sensitive non-eucalypts, but the upper bound of non-eucalypt tree biomass in these eucalypt-dominated systems remains poorly understood.

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