The human–grass–fire cycle: how people and invasives co‐occur to drive fire regimes

2021 ◽  
Author(s):  
Emily J Fusco ◽  
Jennifer K Balch ◽  
Adam L Mahood ◽  
R Chelsea Nagy ◽  
Alexandra D Syphard ◽  
...  
Keyword(s):  
Fire Regimes ◽  
Fire Cycle

scholarly journals Biomonitoring and Inter-Annual Variation of Soil Mite (Acari) Diversity and Community Structure in Lamto Guinean Savannah (Co´te d'Ivoire) Submitted to Different Fire Regimes

2018 ◽  
Vol 5 (1) ◽  
pp. 322-341
Author(s):  
K. Julien N'dri ◽  
Kanvaly Dosso ◽  
Aya B. N'Dri ◽  
Rodolphe Arnaud G. N'Da ◽  
Mouhamadou Kone ◽  
...  
Keyword(s):  
Community Structure ◽  
Annual Variation ◽  
Diversity Index ◽  
Fire Regimes ◽  
Fire Intensity ◽  
Soil Cores ◽  
Fire Cycle ◽  
Soil Mites ◽  
Soil Mite ◽  
The Mean

The objective of the study conducted in the Lamto Guinean savannah situated at 165 km northwest of Abidjan, Cote d'Ivoire consisted to assess the changes in soil mite abundance, diversity and community structure specific to the second fire cycle applied in 2015, as well as the inter-annual variation between the two fire cycles (2014 and 2015). Three study sites (Salty marigot, Plateau and North piste) were selected in shrub savannah, where on each, three adjacent stands of 100 m x 50 m formerly delimited were considered. The three fire regimes (early, mid-season, and late fire) were respectively applied on the three sites and stands. Thus, 135 soil cores (5 soil cores x 3 sampling periods x 3 fire regimes or stands x 3 sites) were used for mite extraction. 108 soil cores were taken at two upper layers (0-5 and 5-10 cm) for determination of the bulk density and water content. Whatever the fire regimes, the mean density of soil mites decreased after the fire application. The highest value of density was observed through the early fire (1,715 ± 327 ind.m-2) whereas the lowest value was recorded during the mid season fire (1,433 ± 153 ind.m-2). 41 species had been recorded along the three fire regimes and distributed as follows: early fire 34 species, mid season fire 20 species, and late fire 13 species. The mean species richness of soil mites changed significantly across the fire regimes, and reduced after the fire application, except for the mid season fire. The Simpson diversity index was significantly modified across the fire regimes, and increased after the fire application. Beyond to 24 specialist species, over 50% of the species observed before the burns were rediscovery after the fire application, and could explain this variation. The inter-annual variation of soil mites showed that the density (early fire, mid season fire, and late fire), mite richness (early fire), and diversity (early fire and late fire) increased whereas the mite richness (mid season fire and late fire), and diversity (mid season fire) decreased, respectively, during 2015-burn compared to the previous cycle (2014-burn). The rebound of soil mite parameters during the second fire cycle could be assigned (i) to litter and woody debris, which burn in a mosaic, reflecting local fire intensity, (ii) improving of stand complexity and canopy structure, and (iii) fire tolerance of mites.

Long fire cycle in northern boreal Pinus forests in Finnish Lapland

2010 ◽  
Vol 40 (10) ◽  
pp. 2027-2035 ◽  
Author(s):  
T. H. Wallenius ◽  
H. Kauhanen ◽  
H. Herva ◽  
J. Pennanen
Keyword(s):  
Cross Sections ◽  
Forest Fires ◽  
Fire Regimes ◽  
Conservation Areas ◽  
Fire Scars ◽  
Fire Cycle ◽  
Structure And Dynamics ◽  
Finnish Lapland ◽  
Dead Trees ◽  
Management Plans

Knowledge of past forest fire regimes is important for developing management plans for conservation areas and for predicting the probable effects of forest management and climate change on the structure and dynamics of forests. In this study, fire scars on living and dead trees were systematically sampled on 256 study plots in three landscapes in northeastern Finland dominated by Scots pine ( Pinus sylvestris L.). A total of 1030 disks or partial cross sections from different trees, including scars from 98 distinct forest fires, were dendrochronologically dated with an accuracy of 1 year or better. The extraordinarily well-preserved old Pinus snags and stumps allowed us to reconstruct annual tree-ring and fire chronologies beginning from the year AD 653. The fire cycles in the studied landscapes were exceptionally long for a boreal region dominated by Pinus, on average 350 years during the last millennium. This demonstrates that the fire regimes of poorly studied remote regions cannot be extrapolated from fire regimes of sites examined in more detail. Based on statistics on lightning-ignition densities, we suggest that most of the fires detected in this study were ignited by humans. The reconstructed past fire cycles were probably shortened by human influence.

Potentially limited detectability of short-term changes in boreal fire regimes: a simulation study

2010 ◽  
Vol 19 (8) ◽  
pp. 1140 ◽  
Author(s):  
Juha M. Metsaranta
Keyword(s):  
Sustainable Forest Management ◽  
Null Model ◽  
Fire Regimes ◽  
Late 20Th Century ◽  
Fire Cycle ◽  
Early 21St Century ◽  
Boreal Plains ◽  
Area Burned ◽  
Wide Range ◽  
In Fire

Climate change is expected to increase area burned in the boreal plains ecozone of Canada in the early 21st century (2001–50). I examined the influence of inter-annual variability in area burned and short observed time series on the probability of detecting if an increase has occurred, using a null model of present and future fire regimes. A wide range of fire cycles are consistent with annual area burned in the late 20th century (1959–99). Fire cycles estimated from the reciprocal of the average annual burn fraction over a 50-year period are not very precise, and overestimate the fire cycle if years with large annual area burned have not recently occurred. Under the default assumptions, the probability of detecting a doubling of annual area burned during 2001–50 is 73% if it occurred instantaneously, but only 31% if it occurred gradually. Imprecise estimates and uncertainty in the ability to detect changes in fire cycles poses challenges for implementing aspects of sustainable forest management. Alternate empirical or model-based statistics, such as return periods for annual areas burned of a given magnitude, may be useful for inferring frequencies and magnitudes of large fire years that have not yet been observed.

scholarly journals Invasive grasses increase fire occurrence and frequency across US ecoregions

2019 ◽  
Vol 116 (47) ◽  
pp. 23594-23599 ◽  
Author(s):  
Emily J. Fusco ◽  
John T. Finn ◽  
Jennifer K. Balch ◽  
R. Chelsea Nagy ◽  
Bethany A. Bradley
Keyword(s):  
Expert Knowledge ◽  
Fire Regimes ◽  
Grass Species ◽  
Fire Occurrence ◽  
Invasive Grass ◽  
Pennisetum Ciliare ◽  
Fire Cycle ◽  
Invasive Grasses ◽  
In Fire ◽  
Grass Invasion

Fire-prone invasive grasses create novel ecosystem threats by increasing fine-fuel loads and continuity, which can alter fire regimes. While the existence of an invasive grass-fire cycle is well known, evidence of altered fire regimes is typically based on local-scale studies or expert knowledge. Here, we quantify the effects of 12 nonnative, invasive grasses on fire occurrence, size, and frequency across 29 US ecoregions encompassing more than one third of the conterminous United States. These 12 grass species promote fire locally and have extensive spatial records of abundant infestations. We combined agency and satellite fire data with records of abundant grass invasion to test for differences in fire regimes between invaded and nearby “uninvaded” habitat. Additionally, we assessed whether invasive grass presence is a significant predictor of altered fire by modeling fire occurrence, size, and frequency as a function of grass invasion, in addition to anthropogenic and ecological covariates relevant to fire. Eight species showed significantly higher fire-occurrence rates, which more than tripled for Schismus barbatus and Pennisetum ciliare. Six species demonstrated significantly higher mean fire frequency, which more than doubled for Neyraudia reynaudiana and Pennisetum ciliare. Grass invasion was significant in fire occurrence and frequency models, but not in fire-size models. The significant differences in fire regimes, coupled with the importance of grass invasion in modeling these differences, suggest that invasive grasses alter US fire regimes at regional scales. As concern about US wildfires grows, accounting for fire-promoting invasive grasses will be imperative for effectively managing ecosystems.

scholarly journals Wildfire, climate, and invasive grass interactions negatively impact an indicator species by reshaping sagebrush ecosystems

2016 ◽  
Vol 113 (45) ◽  
pp. 12745-12750 ◽  
Author(s):  
Peter S. Coates ◽  
Mark A. Ricca ◽  
Brian G. Prochazka ◽  
Matthew L. Brooks ◽  
Kevin E. Doherty ◽  
...  
Keyword(s):  
Great Basin ◽  
Indicator Species ◽  
Spatial Scales ◽  
Fire Regimes ◽  
Invasive Grass ◽  
Sage Grouse ◽  
Climatic Effects ◽  
Ecosystem Recovery ◽  
Fire Cycle ◽  
Wildlife Populations

Iconic sagebrush ecosystems of the American West are threatened by larger and more frequent wildfires that can kill sagebrush and facilitate invasion by annual grasses, creating a cycle that alters sagebrush ecosystem recovery post disturbance. Thwarting this accelerated grass–fire cycle is at the forefront of current national conservation efforts, yet its impacts on wildlife populations inhabiting these ecosystems have not been quantified rigorously. Within a Bayesian framework, we modeled 30 y of wildfire and climatic effects on population rates of change of a sagebrush-obligate species, the greater sage-grouse, across the Great Basin of western North America. Importantly, our modeling also accounted for variation in sagebrush recovery time post fire as determined by underlying soil properties that influence ecosystem resilience to disturbance and resistance to invasion. Our results demonstrate that the cumulative loss of sagebrush to direct and indirect effects of wildfire has contributed strongly to declining sage-grouse populations over the past 30 y at large spatial scales. Moreover, long-lasting effects from wildfire nullified pulses of sage-grouse population growth that typically follow years of higher precipitation. If wildfire trends continue unabated, model projections indicate sage-grouse populations will be reduced to 43% of their current numbers over the next three decades. Our results provide a timely example of how altered fire regimes are disrupting recovery of sagebrush ecosystems and leading to substantial declines of a widespread indicator species. Accordingly, we present scenario-based stochastic projections to inform conservation actions that may help offset the adverse effects of wildfire on sage-grouse and other wildlife populations.

Historical fire regime shifts related to climate teleconnections in the Waswanipi area, central Quebec, Canada

2007 ◽  
Vol 16 (5) ◽  
pp. 607 ◽  
Author(s):  
Héloïse Le Goff ◽  
Mike D. Flannigan ◽  
Yves Bergeron ◽  
Martin P. Girardin
Keyword(s):  
Large Scale ◽  
Fire Regime ◽  
Age Distribution ◽  
Fire Regimes ◽  
Positive Influence ◽  
Regime Shifts ◽  
Climate Indices ◽  
Eastern Canada ◽  
Fire Cycle ◽  
Fire Activity

The synchrony of regional fire regime shifts across the Quebec boreal forest, eastern Canada, suggests that regional fire regimes are influenced by large-scale climate variability. The present study investigated the relationship of the forest-age distribution, reflecting the regional fire activity, to large-scale climate variations. The interdecadal variation in forest fire activity in the Waswanipi area, north-eastern Canada, was reconstructed over 1720–2000. Next, the 1880–2000 reconstructed fire activity was analysed using different proxies of the Pacific Decadal Oscillation (PDO) and the North Atlantic Oscillation (NAO) and the Atlantic Multidecadal Oscillation (AMO). We estimated the global fire cycle around 132–153 years, with a major lengthening of the fire cycle from 99 years before 1940, to 282 years after 1940. Correlations between decadal fire activity and climate indices indicated a positive influence of the PDO. The positive influence of PDO on regional fire activity was also validated using t-tests between fire years and non-fire years between 1899 and 1996. Our results confirmed recent findings on the positive influence of the PDO on the fire activity over northern Quebec and the reinforcing role of the NAO in this relationship.

Transformation

2018 ◽  
Author(s):  
Karen J. Esler ◽  
Anna L. Jacobsen ◽  
R. Brandon Pratt
Keyword(s):  
Climate Change ◽  
Fire Regimes ◽  
Human Populations ◽  
Land Use Land Cover ◽  
Mountainous Areas ◽  
Drivers Of Change ◽  
Natural Systems ◽  
Natural Landscapes ◽  
Habitat Conversion ◽  
Residential Use

Extensive habitat loss and habitat conversion has occurred across all mediterranean-type climate (MTC) regions, driven by increasing human populations who have converted large tracts of land to production, transport, and residential use (land-use, land-cover change) while simultaneously introducing novel forms of disturbance to natural landscapes. Remaining habitat, often fragmented and in isolated or remote (mountainous) areas, is threatened and degraded by altered fire regimes, introduction of invasive species, nutrient enrichment, and climate change. The types and impacts of these threats vary across MTC regions, but overall these drivers of change show little signs of abatement and many have the potential to interact with MTC region natural systems in complex ways.

scholarly journals The changes in species composition mediate direct effects of climate change on future fire regimes of boreal forests in northeastern China

2021 ◽  
Author(s):  
Chao Huang ◽  
Hong S. He ◽  
Yu Liang ◽  
Todd J. Hawbaker ◽  
Paul D. Henne ◽  
...  
Keyword(s):  
Climate Change ◽  
Species Composition ◽  
Boreal Forests ◽  
Fire Regimes ◽  
Northeastern China ◽  
Direct Effects

scholarly journals A reconstruction of the recent fire regimes of Majete Wildlife Reserve, Malawi, using remote sensing

Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Willem A. Nieman ◽  
Brian W. van Wilgen ◽  
Alison J. Leslie
Keyword(s):  
Remote Sensing ◽  
Fire Management ◽  
Fire Regime ◽  
Fire Regimes ◽  
Dry Season ◽  
Annual Rainfall ◽  
Vegetation Types ◽  
Local Evidence ◽  
Hot Dry Season ◽  
Wildlife Reserve

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.

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