Late-Holocene climate changes linked to ecosystem shifts in the Northwest Wisconsin Sand Plain, USA

The Holocene ◽  
2020 ◽  
pp. 095968362097276
Author(s):  
Randy Calcote ◽  
Christopher Nevala-Plagemann ◽  
Elizabeth A Lynch ◽  
Sara C Hotchkiss
Keyword(s):  
Lake Level ◽  
Vegetation Change ◽  
Fire Regime ◽  
Sediment Cores ◽  
Fire Regimes ◽  
Upper Midwest ◽  
Moisture Availability ◽  
Sand Plain ◽  
Oak Pollen ◽  
Ecosystem Changes

Records of century-scale climate variability in the Upper Midwest generally agree that moisture availability increased between 4000 and 3000 cal. yr BP (calendar years before present = 1950 CE), and that there were large, frequent droughts 1000–700 cal. yr BP followed by wetter/cooler conditions. Variability among regional sites, however, remains problematic. In this study we reconstruct climate on the Northwest Wisconsin Sand Plain (NWSP), USA, to identify potential climatic drivers of previously documented changes in vegetation and fire regimes. Oak pollen was replaced by pollen from xeric pine taxa at several sites on the NWSP ~1425 cal. yr BP, accompanied by a change to larger, less frequent charcoal peaks. Another major vegetation change occurred ~700 cal. yr BP, when pollen of the more mesic P. strobus L. (white pine) increased and charcoal influx decreased. We used a vegetation-independent lake-level record to determine whether long-term changes in moisture availability were associated with these ecosystem changes. Decreases in percent organic matter in shallow-water sediment cores from Cheney Lake indicate that the lake level decreased sharply ~1500 cal. yr BP, consistent with the interpretation that the changes in vegetation and fire regime were driven by a severe and previously undocumented drought. The lake level rose again, reaching approximately modern levels by 800–700 cal. yr BP, consistent with the hypothesis of cooler/wetter conditions in the Upper Midwest in the past ~700 years and with the expansion of mesic taxa on the NWSP 700 cal. yr BP.

Fire regime and vegetation change in the transition from Aboriginal to European land management in a Tasmanian eucalypt savanna

2016 ◽  
Vol 64 (5) ◽  
pp. 427 ◽  
Author(s):  
Louise M. Romanin ◽  
Feli Hopf ◽  
Simon G. Haberle ◽  
David M. J. S. Bowman
Keyword(s):  
Vegetation Change ◽  
Fire Regime ◽  
Plantago Lanceolata ◽  
Sediment Cores ◽  
Open Water ◽  
Fire Regimes ◽  
Ecological Impacts ◽  
14C Dating ◽  
Early 19Th Century ◽  
European Settlement

Using pollen and charcoal analysis we examined how vegetation and fire regimes have changed over the last 600 years in the Midlands of Tasmania. Sediment cores from seven lagoons were sampled, with a chronology developed at one site (Diprose Lagoon) using 210Pb and 14C dating. Statistical contrasts of six cores where Pinus served as a marker of European settlement in the early 19th Century and showed significant changes in pollen composition following settlement with (a) influx of ruderal exotic taxa including Plantago lanceolata L., Brassicaceae, Asteraceae (Liguliflorae) and Rumex, (b) increase in pollen of the aquatics Myriophyllum spp. and Cyperaceae, (c) a decline in native herbaceous pollen taxa, including Chenopodiaceae and Asteraceae (Tubuliflorae) and (d) a decline in Allocasuarina and an initial decline and then increase of Poaceae. The presence of Asteraceae (Liguliflorae) in the pre-European period suggests that an important root vegetable Microseris lanceolata (Walp.) Sch.Bip. may have been abundant. Charcoal deposition was low in the pre-European period and significantly increased immediately after European arrival. Collectively, these changes suggest substantial ecological impacts following European settlement including cessation of Aboriginal traditions of fire management, a shift in hydrological conditions from open water lagoons to more ephemeral herb covered lagoons, and increased diversity of alien herbaceous species following pasture establishment.

European colonization and the emergence of novel fire regimes in southeast Australia

2021 ◽  
pp. 205301962110446
Author(s):  
Matthew Adesanya Adeleye ◽  
Simon Edward Connor ◽  
Simon Graeme Haberle ◽  
Annika Herbert ◽  
Josephine Brown
Keyword(s):  
Vegetation Change ◽  
Fire History ◽  
Fire Regime ◽  
Biomass Accumulation ◽  
Fire Regimes ◽  
Management Approach ◽  
Southeast Australia ◽  
Generalized Linear Modelling ◽  
Indigenous Land Management ◽  
European Colonization

The rapid increase in severe wildfires in many parts of the world, especially in temperate systems, requires urgent attention to reduce fires’ catastrophic impacts on human lives, livelihoods, health and economy. Of particular concern is southeast Australia, which harbours one of the most flammable vegetation types on Earth. While previous studies suggest climate and European activities drove changes in southeast Australian fire regimes in the last 200 years, no study has quantitatively tested the relative roles of these drivers. Here, we use a Generalized Linear Modelling to identify the major driver(s) of fire regime change in the southeast Australian mainland during and prior to European colonization. We use multiple charcoal and pollen records across the region and quantitatively compare fire history to records of climate and vegetation change. Results show low levels of biomass burned before colonization, when landscapes where under Indigenous management, even under variable climates. Biomass burned increased markedly due to vegetation/land-use change after colonization and a major decline in regional precipitation about 100 years later. We conclude that Indigenous-maintained open vegetation minimized the amount of biomass burned prior to colonization, while European-suppression of Indigenous land management has amplified biomass accumulation and fuel connectivity in southeast Australian forests since colonization. While climate change remains a major challenge for fire mitigation, implementation of a management approach similar to the pre-colonial period is suggested to ameliorate the risk of future catastrophic fires in the region.

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.

Eighty years of change: vegetation in the montane ecoregion of Jasper National Park, Alberta, Canada

2002 ◽  
Vol 32 (11) ◽  
pp. 2010-2021 ◽  
Author(s):  
Jeanine M Rhemtulla ◽  
Ronald J Hall ◽  
Eric S Higgs ◽  
S Ellen Macdonald
Keyword(s):  
National Park ◽  
Vegetation Change ◽  
Fire Regime ◽  
Reference Conditions ◽  
Habitat Diversity ◽  
Climatic Conditions ◽  
Aerial Photographs ◽  
Contributing Factors ◽  
Jasper National Park ◽  
Closed Canopy

Repeat ground photographs (taken in 1915 and 1997) from a series of topographical survey stations and repeat aerial photographs (flown in 1949 and 1991) were analysed to assess changes in vegetation composition and distribution in the montane ecoregion of Jasper National Park, in the Rocky Mountains of Alberta, Canada. A quantitative approach for assessing relative vegetation change in repeat ground photographs was developed and tested. The results indicated a shift towards late-successional vegetation types and an increase in crown closure in coniferous stands. Grasslands, shrub, juvenile forest, and open forests decreased in extent, and closed-canopy forests became more prevalent. The majority of forest stands succeeded to dominance by coniferous species. Changes in vegetation patterns were likely largely attributable to shifts in the fire regime over the last century, although climatic conditions and human activity may also have been contributing factors. Implications of observed changes include decreased habitat diversity, increased possibility of insect outbreaks, and potential for future high-intensity fire events. Results of the study increase knowledge of historical reference conditions and may help to establish restoration goals for the montane ecoregion of the park.

Fire regime shift linked to increased forest density in a piñon–juniper savanna landscape

2014 ◽  
Vol 23 (2) ◽  
pp. 234 ◽  
Author(s):  
Ellis Q. Margolis
Keyword(s):  
Regime Shift ◽  
Fire History ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Climatic Conditions ◽  
Tree Density ◽  
High Severity ◽  
Wide Range ◽  
In Fire

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.

The Neogene transition from C3 to C4 grasslands in North America: assemblage analysis of fossil phytoliths

Paleobiology ◽  
2011 ◽  
Vol 37 (1) ◽  
pp. 50-71 ◽  
Author(s):  
Caroline A. E. Strömberg ◽  
Francesca A. McInerney
Keyword(s):  
North America ◽  
Great Plains ◽  
Late Miocene ◽  
Vegetation Change ◽  
Stable Carbon Isotopes ◽  
Fire Regime ◽  
Tooth Enamel ◽  
Regional Scale ◽  
Grassland Ecosystems ◽  
Isotopic Records

The rapid ecological expansion of grasses with C4 photosynthesis at the end of the Neogene (8–2 Ma) is well documented in the fossil record of stable carbon isotopes. As one of the most profound vegetation changes to occur in recent geologic time, it paved the way for modern tropical grassland ecosystems. Changes in CO2 levels, seasonality, aridity, herbivory, and fire regime have all been suggested as potential triggers for this broadly synchronous change, long after the evolutionary origin of the C4 pathway in grasses. To date, these hypotheses have suffered from a lack of direct evidence for floral composition and structure during this important transition. This study aimed to remedy the problem by providing the first direct, relatively continuous record of vegetation change for the Great Plains of North America for the critical interval (ca. 12–2 Ma) using plant silica (phytolith) assemblages.Phytoliths were extracted from late Miocene-Pliocene paleosols in Nebraska and Kansas. Quantitative phytolith analysis of the 14 best-preserved assemblages indicates that habitats varied substantially in openness during the middle to late Miocene but became more uniformly open, corresponding to relatively open grassland or savanna, during the late Miocene and early Pliocene. Phytolith data also point to a marked increase of grass short cells typical of chloridoid and other potentially C4 grasses of the PACMAD clade between 8 and 5 Ma; these data suggest that the proportion of these grasses reached up to ∼50–60% of grasses, resulting in mixed C3-C4 and highly heterogeneous grassland communities by 5.5 Ma. This scenario is consistent with interpretations of isotopic records from paleosol carbonates and ungulate tooth enamel. The rise in abundance of chloridoids, which were present in the central Great Plains since the early Miocene, demonstrates that the “globally” observed lag between C4 grass evolution/taxonomic diversification and ecological expansion occurred at the regional scale. These patterns of vegetation alteration imply that environmental change during the late Miocene-Pliocene played a major role in the C3-C4 shift in the Great Plains. Specifically, the importance of chloridoids as well as a decline in the relative abundance of forest indicator taxa, including palms, point to climatic drying as a key trigger for C4 dominance.

Fire Management of Rangelands in the Kimberley Low-Rainfall Zone: a Review.

1999 ◽  
Vol 21 (1) ◽  
pp. 39 ◽  
Author(s):  
AB Craig
Keyword(s):  
Fire History ◽  
Fire Management ◽  
Fire Regime ◽  
Fire Regimes ◽  
Environmental Research ◽  
Fire Behaviour ◽  
General Management ◽  
Noaa Avhrr ◽  
Local Experience ◽  
Definition Of

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

Charcoal signatures defined by multivariate analysis of charcoal records from 10 lakes in northwest Wisconsin (USA)

2011 ◽  
Vol 75 (1) ◽  
pp. 125-137 ◽  
Author(s):  
Elizabeth A. Lynch ◽  
Sara C. Hotchkiss ◽  
Randy Calcote
Keyword(s):  
Late Holocene ◽  
Climate Changes ◽  
Regional Climate ◽  
Fire Regimes ◽  
Small Scale ◽  
Regional Patterns ◽  
Crown Fires ◽  
Sand Plain ◽  
In Fire ◽  
Standard Techniques

AbstractWe show how sedimentary charcoal records from multiple sites within a single landscape can be used to compare fire histories and reveal small scale patterns in fire regimes. Our objective is to develop strategies for classifying and comparing late-Holocene charcoal records in Midwestern oak- and pine-dominated sand plain ecosystems where fire regimes include a mix of surface and crown fires. Using standard techniques for the analysis of charcoal from lake sediments, we compiled 1000- to 4000-yr-long records of charcoal accumulation and charcoal peak frequencies from 10 small lakes across a sand plain in northwestern Wisconsin. We used cluster analysis to identify six types of charcoal signatures that differ in their charcoal influx rates, amount of grass charcoal, and frequency and magnitude of charcoal peaks. The charcoal records demonstrate that while fire histories vary among sites, there are regional patterns in the occurrence of charcoal signature types that are consistent with expected differences in fire regimes based on regional climate and vegetation reconstructions. The fire histories also show periods of regional change in charcoal signatures occurring during times of regional climate changes at ~700, 1000, and 3500 cal yr BP.

Fire regime impacts on post-fire diurnal land surface temperature change over North American boreal forest

2021 ◽  
Author(s):  
Jie Zhao ◽  
Chao Yue ◽  
Philippe Ciais ◽  
Xin Hou ◽  
Qi Tian
Keyword(s):  
Climate Change ◽  
Regression Analysis ◽  
Land Surface ◽  
Fire Regime ◽  
Fire Severity ◽  
Linear Regression Analysis ◽  
Fire Regimes ◽  
Fire Intensity ◽  
Surface Temperature Change ◽  
One Year

<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>

Fungi and plant co-variation in Arctic Siberia inferred from sedimentary ancient DNA metabarcoding during the last 45.000 years

2021 ◽  
Author(s):  
Barbara von Hippel ◽  
Kathleen R. Stoof-Leichsenring ◽  
Luise Schulte ◽  
Peter Seeber ◽  
Laura S. Epp ◽  
...  
Keyword(s):  
Climate Change ◽  
Ancient Dna ◽  
Mycorrhizal Fungi ◽  
Vegetation Change ◽  
Sediment Cores ◽  
Siberian Larch ◽  
Biotic Interactions ◽  
Arctic Ecosystems ◽  
Arctic Regions ◽  
Arctic Siberia

<p>Climate change has a great impact on boreal ecosystems including Siberian larch forests. As a consequence of warming, larch grow is possible in areas where climate used to be too cold, leading to a shift of the tree line into more arctic regions. Most plants co-exist in symbiosis with heterotrophic organisms surrounding their root system. In arctic ecosystems, mycorrhizal fungi are a prerequisite for plant establishment and survival because they support nutrient uptake from nutrient-poor soils and maintain the water supply. Until now, however, knowledge about the co-variation of vegetation and fungi is poor. Certainly, the understanding of dynamic changes in biotic interactions is important to understand adaptation mechanisms of ecosystems to climate change.</p><p>We investigated sedimentary ancient DNA from Lake Levinson Lessing, Taymyr Peninsula (Arctic Siberia, tundra), Lake Lama, Lake Kyutyunda (both northern Siberia, tundra-taiga transition zone) and Lake Bolshoe Toko (southern Siberia, forest area) covering the last about 45.000 years using ITS primers for fungi along with the chloroplast P6 loop marker for vegetation metabarcoding. We found changes in the fungal communities that are in broad agreement with vegetation turnover. To our knowledge, this is the first broad ecological study on lake sediment cores to analyze fungal biodiversity in relation to vegetation change on millennial time scales.</p>

Sign in / Sign up

Export Citation Format

Share Document