Which mosaic? A landscape ecological approach for evaluating interactions between fire regimes, habitat and animals

2005 ◽  
Vol 32 (5) ◽  
pp. 409 ◽  
Author(s):  
R. A. Bradstock ◽  
M. Bedward ◽  
A. M. Gill ◽  
J. S. Cohn

The link between ‘fire mosaics’ and persistence of animal species is part of a prominent ecological/land management paradigm. This paradigm deals largely with the effects of fire on animals on the basis of individual events. The universality of the paradigm can be questioned on a variety of grounds, a major deficiency being the inability to deal with quantitative effects of recurrent fire (the fire regime). A conceptual model of fire-related habitat elements is proposed for exploration of a continuum of species/habitat/landscape/fire regime combinations. This approach predicts that the dependence of species on fire-mediated habitat heterogeneity will be highly variable and strongly context-dependent. A spatially explicit simulation model was used to examine the persistence of malleefowl (Leipoa ocellata) in a specific landscape/habitat context where dependence on fire-mosaics should be high. Results suggest that persistence of L. ocellata populations will be dependent on intervention using small patchy fires but that there is an optimum rate of intervention. Results were sensitive to spatial pattern of prescribed fire, landscape type (topography) and probability of wildfire. Underlying effects of the fire-interval distribution (the ‘invisible’ mosaic) on plant species and habitat account for these results. A management emphasis on species/landscape context and awareness of the ‘invisible’ mosaic is advocated.

2019 ◽  
Vol 139 (3) ◽  
pp. 393-406
Author(s):  
Sarah Cogos ◽  
Samuel Roturier ◽  
Lars Östlund

AbstractIn Sweden, prescribed burning was trialed as early as the 1890s for forest regeneration purposes. However, the origins of prescribed burning in Sweden are commonly attributed to Joel Efraim Wretlind, forest manager in the State Forest district of Malå, Västerbotten County, from 1920 to 1952. To more fully understand the role he played in the development of prescribed burning and the extent of his burning, we examined historical records from the State Forest Company’s archive and Wretlind’s personal archive. The data showed that at least 11,208 ha was burned through prescribed burning between 1921 and 1970, representing 18.7% of the Malå state-owned forest area. Wretlind thus created a new forestry-driven fire regime, reaching, during peak years, extents close to historical fire regimes before the fire suppression era, and much higher than present-day burning. His use of prescribed fire to regenerate forests served as a guide for many other forest managers, spreading to all of northern Sweden during the 1950–1960s. Our analysis of Wretlind’s latest accounts also shows how he stood against the evolutions of modern forestry to defend a forestry system based on the reproduction of natural processes, such as fire.


2017 ◽  
Vol 26 (5) ◽  
pp. 434 ◽  
Author(s):  
Julian Brown ◽  
Alan York

It is increasingly recognised that fire management for biodiversity conservation must account for two kinds of landscape mosaics: 1) the ‘visible’ mosaic of post-fire age classes as it relates to organism responses to the most recent fire events; and 2) the ‘invisible’ mosaic of inter-fire intervals, frequencies and other components of the fire regime as they relate to the cumulative effects of multiple fires. Patch mosaic burning (PMB) aims to create landscape mosaics of fire ages to cater for the needs of a diversity of species differing in their age class preferences, but empirical studies often fail to detect a link between species richness and the visible mosaic. Empirical studies of cumulative effects have so far related species richness to the fire regimes of sample locations rather than the invisible mosaic, within which sample locations are embedded. Invertebrate responses to landscape fire mosaics are particularly poorly understood, so we investigated relationships between fire history heterogeneity and fly and wasp species richness. We find support for the PMB paradigm and the notion the invisible mosaic influences species richness. To the best of our knowledge, this is the first empirical test of the invisible mosaic’s influence on animal communities.


2013 ◽  
Vol 43 (8) ◽  
pp. 757-767 ◽  
Author(s):  
Patrick H. Brose ◽  
Daniel C. Dey ◽  
Richard P. Guyette ◽  
Joseph M. Marschall ◽  
Michael C. Stambaugh

Understanding past fire regimes is necessary to justify and implement restoration of disturbance-associated forests via prescribed fire programs. In eastern North America, the characteristics of many presettlement fire regimes are unclear because of the passage of time. To help clarify this situation, we developed a 435-year fire history for the former conifer forests of northern Pennsylvania. Ninety-three cross sections of fire-scarred red pines (Pinus resinosa Aiton) collected from three sites were analyzed to determine common fire regime characteristics. Prior to European settlement, fires occurred every 35–50 years and were often large dormant-season burns that sometimes initiated red pine regeneration. American Indians probably ignited these fires. Fire occurrence had a weak association with multiyear droughts. After European settlement started around 1800, fires occurred every 5–7 years due to widespread logging. Fire size and seasonality expanded to include small growing-season fires. The weak drought–fire association ceased. In the early 1900s, logging ended and wildfire control began. Since then, fires have been nearly absent from the sites despite several multiyear droughts in the 20th century. The human influences of cultural burning, logging, and fire exclusion are more important than the influence of drought to the fire regimes of northern Pennsylvania.


Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Willem A. Nieman ◽  
Brian W. van Wilgen ◽  
Alison J. Leslie

Abstract Background Fire is an important process that shapes the structure and functioning of African savanna ecosystems, and managers of savanna protected areas use fire to achieve ecosystem goals. Developing appropriate fire management policies should be based on an understanding of the determinants, features, and effects of prevailing fire regimes, but this information is rarely available. In this study, we report on the use of remote sensing to develop a spatially explicit dataset on past fire regimes in Majete Wildlife Reserve, Malawi, between 2001 and 2019. Moderate Resolution Imaging Spectroradiometer (MODIS) images were used to evaluate the recent fire regime for two distinct vegetation types in Majete Wildlife Reserve, namely savanna and miombo. Additionally, a comparison was made between MODIS and Visible Infrared Imager Radiometer Suite (VIIRS) images by separately evaluating selected aspects of the fire regime between 2012 and 2019. Results Mean fire return intervals were four and six years for miombo and savanna vegetation, respectively, but the distribution of fire return intervals was skewed, with a large proportion of the area burning annually or biennially, and a smaller proportion experiencing much longer fire return intervals. Variation in inter-annual rainfall also resulted in longer fire return intervals during cycles of below-average rainfall. Fires were concentrated in the hot-dry season despite a management intent to restrict burning to the cool-dry season. Mean fire intensities were generally low, but many individual fires had intensities of 14 to 18 times higher than the mean, especially in the hot-dry season. The VIIRS sensors detected many fires that were overlooked by the MODIS sensors, as images were collected at a finer scale. Conclusions Remote sensing has provided a useful basis for reconstructing the recent fire regime of Majete Wildlife Reserve, and has highlighted a current mismatch between intended fire management goals and actual trends. Managers should re-evaluate fire policies based on our findings, setting clearly defined targets for the different vegetation types and introducing flexibility to accommodate natural variation in rainfall cycles. Local evidence of the links between fires and ecological outcomes will require further research to improve fire planning.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ruikang Li ◽  
Yangbing Li ◽  
Bo Li ◽  
Dianji Fu

AbstractAnalyses of landscape change patterns that are based on elevation and slope can not only provide reasonable interpretations of landscape patterns but can also help to reveal evolutionary laws. However, landscape change patterns and their model in different landforms of the typical watershed in the Three Gorges Reservoir Area (TGRA) has not been quantified and assessed effectively. As a complex geographical unit, the ecological environment in the middle reach of the Yangtze River has experienced great changes due to the construction of the Three Gorges Project (TGP) and its associated human activities. Here, based mainly on a digital elevation model (DEM) and remotely sensed images from 1986, 2000, 2010, and 2017 and by using GIS technology, speeds/ trends of landscape change, the index of landscape type change intensity, landscape pattern indices, and landscape ecological security index, the spatial and temporal evolution characteristics of different elevations, slopes, and buffer landscape types were analyzed in typical watersheds, as well as an evolutionary model of the landscape pattern. The results indicated that (1) the landscape types along with the land classification and buffer zone that were influenced by the TGR construction have undergone a phased change, with the period 2000–2010 being the most dramatic period of landscape evolution during the impoundment period; (2) landscape type shifts from human-dominated farmland to nature-driven forestland and shrub-land as elevations, slopes and buffer distances increased. The landscape has shifted from diversity to relative homogeneity; (3) land types and buffer zones played essential roles in the landscape pattern index, which is reflected in the differences in landscape type indices for spatial extension and temporal characteristics. The results of this paper illustrate the spatial–temporal characteristics of various landscape types at three distinct stages in the construction of the TGR. These findings indicate that the landscape ecological security of the watershed is improving year by year. The follow-up development of the TGRA needs to consider the landscape change patterns of different landforms.


2014 ◽  
Vol 23 (2) ◽  
pp. 234 ◽  
Author(s):  
Ellis Q. Margolis

Piñon–juniper (PJ) fire regimes are generally characterised as infrequent high-severity. However, PJ ecosystems vary across a large geographic and bio-climatic range and little is known about one of the principal PJ functional types, PJ savannas. It is logical that (1) grass in PJ savannas could support frequent, low-severity fire and (2) exclusion of frequent fire could explain increased tree density in PJ savannas. To assess these hypotheses I used dendroecological methods to reconstruct fire history and forest structure in a PJ-dominated savanna. Evidence of high-severity fire was not observed. From 112 fire-scarred trees I reconstructed 87 fire years (1547–1899). Mean fire interval was 7.8 years for fires recorded at ≥2 sites. Tree establishment was negatively correlated with fire frequency (r=–0.74) and peak PJ establishment was synchronous with dry (unfavourable) conditions and a regime shift (decline) in fire frequency in the late 1800s. The collapse of the grass-fuelled, frequent, surface fire regime in this PJ savanna was likely the primary driver of current high tree density (mean=881treesha–1) that is >600% of the historical estimate. Variability in bio-climatic conditions likely drive variability in fire regimes across the wide range of PJ ecosystems.


1999 ◽  
Vol 21 (1) ◽  
pp. 39 ◽  
Author(s):  
AB Craig

This paper examines a range of environmental, research and practical issues affecting fire management of pastoral lands in the southern part of the Kimberley region in Western Australia. Although spinifex grasslands dominate most leases, smaller areas of more productive pastures are crucially important to many enterprises. There is a lack of local documentation of burning practices during traditional Aboriginal occupation; general features of the fire regime at that time can be suggested on the basis of information from other inland areas. Definition of current tire regimes is improving through interpretation of NOAA-AVHRR satellite imagery. Irregular extensive wildfires appear to dominate, although this should be confirmed by further accumulation, validation and analysis of fire history data. While these fires cause ma,jor difficulties. controlled burn~ng is a necessary part of station management. Although general management guidelines have been published. local research into tire-grazing effects has been very limited. For spinifex pastures, reconimendations are generally consistent with those applying elsewhere in northern Australia. They favour periodic burning of mature spinifex late in the year, before or shortly after the arrival of the first rains, with deferment of grazing. At that time. days of high fire danger may still be expected and prediction of fire behaviour is critical to burning decisions. Early dry-season burning is also required for creating protective tire breaks and to prepare for burning later in the year. Further development of tools for predicting fire behaviour, suited to the discontinuous fuels characteristic of the area, would be warranted. A range of questions concerning the timing and spatial pattern of burning, control of post-fire grazing, and the economics of fire management, should be addressed as resources permit. This can be done through a combination of opportunistic studies, modelling and documentation of local experience. The development of an expert system should be considered to assist in planning and conducting burning activities. Key words: Kimberley, fire regimes, fire management, pastoralism, spinifex


2012 ◽  
Vol 21 (3) ◽  
pp. 297 ◽  
Author(s):  
Owen F. Price ◽  
Jeremy Russell-Smith ◽  
Felicity Watt

Fire regimes in many north Australian savanna regions are today characterised by frequent wildfires occurring in the latter part of the 7-month dry season. A fire management program instigated from 2005 over 24 000 km2 of biodiversity-rich Western Arnhem Land aims to reduce the area and severity of late dry-season fires, and associated greenhouse gas emissions, through targeted early dry-season prescribed burning. This study used fire history mapping derived mostly from Landsat imagery over the period 1990–2009 and statistical modelling to quantify the mitigation of late dry-season wildfire through prescribed burning. From 2005, there has been a reduction in mean annual total proportion burnt (from 38 to 30%), and particularly of late dry-season fires (from 29 to 12.5%). The slope of the relationship between the proportion of early-season prescribed fire and subsequent late dry-season wildfire was ~–1. This means that imposing prescribed early dry-season burning can substantially reduce late dry-season fire area, by direct one-to-one replacement. There is some evidence that the spatially strategic program has achieved even better mitigation than this. The observed reduction in late dry-season fire without concomitant increase in overall area burnt has important ecological and greenhouse gas emissions implications. This efficient mitigation of wildfire contrasts markedly with observations reported from temperate fire-prone forested systems.


2021 ◽  
Author(s):  
Jie Zhao ◽  
Chao Yue ◽  
Philippe Ciais ◽  
Xin Hou ◽  
Qi Tian

<p>Wildfire is the most prevalent natural disturbance in the North American boreal (BNA) forest and can cause post-fire land surface temperature change (ΔLST<sub>fire</sub>) through biophysical processes. Fire regimes, such as fire severity, fire intensity and percentage of burned area (PBA), might affect ΔLST<sub>fire</sub> through their impacts on post-fire vegetation damage. However, the difference of the influence of different fire regimes on the ΔLST<sub>fire</sub> has not been quantified in previous studies, despite ongoing and projected changes in fire regimes in BNA in association with climate change. Here we employed satellite observations and a space-and-time approach to investigate diurnal ΔLST<sub>fire</sub> one year after fire across BNA. We further examined potential impacts of three fire regimes (i.e., fire intensity, fire severity and PBA) and latitude on ΔLST<sub>fire</sub> by simple linear regression analysis and multiple linear regression analysis in a stepwise manner. Our results demonstrated pronounced asymmetry in diurnal ΔLST<sub>fire</sub>, characterized by daytime warming in contrast to nighttime cooling over most BNA. Such diurnal ΔLST<sub>fire</sub> also exhibits a clear latitudinal pattern, with stronger daytime warming and nighttime cooling one year after fire in lower latitudes, whereas in high latitudes fire effects are almost neutral. Among the fire regimes, fire severity accounted for the most (43.65%) of the variation of daytime ΔLST<sub>fire</sub>, followed by PBA (11.6%) and fire intensity (8.5%). The latitude is an important factor affecting the influence of fire regimes on daytime ΔLST<sub>fire</sub>. The sensitivity of fire intensity and PBA impact on daytime ΔLST<sub>fire</sub> decreases with latitude. But only fire severity had a significant effect on nighttime ΔLST<sub>fire</sub> among three fire regimes. Our results highlight important fire regime impacts on daytime ΔLST<sub>fire</sub>, which might play a critical role in catalyzing future boreal climate change through positive feedbacks between fire regime and post-fire surface warming.</p>


2018 ◽  
Vol 35 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Kouamé Fulgence Koffi ◽  
Aya Brigitte N’Dri ◽  
Jean-Christophe Lata ◽  
Souleymane Konaté ◽  
Tharaniya Srikanthasamy ◽  
...  

AbstractThis study assesses the impact of four fire treatments applied yearly over 3 y, i.e. early fire, mid-season fire, late fire and no fire treatments, on the grass communities of Lamto savanna, Ivory Coast. We describe communities of perennial tussock grasses on three replicated 5 × 5-m or 10 × 5-m plots of each fire treatment. Tussock density did not vary with fire treatment. The relative abundance of grass species, the circumference of grass tussocks and the probability of having a tussock with a central die-back, varied with fire treatment. Mid-season fire had the highest proportion of tussocks with a central die-back while the late fire had the smallest tussocks. Tussock density, circumference, relative abundance and probability of having a central die-back varied with species. Andropogon canaliculatus and Hyparrhenia diplandra were the most abundant of the nine grass species. They had the largest tussocks and the highest proportion of tussock with a central die-back. Loudetia simplex was the third most abundant species but was very rare in no fire plots. The distribution of tussock circumferences was right skewed and dominated by small tussocks. The proportion of the tussocks with a central die-back strongly increased with circumference, which could lead to tussock fragmentation. Taken together, this study suggests that fire regimes impact grass demography and that this impact depends on grass species and tussock size.


Sign in / Sign up

Export Citation Format

Share Document