Livestock Grazing-Fire Regime Interactions within Montane Forests of Zion National Park, Utah

Ecology ◽  
1983 ◽  
Vol 64 (4) ◽  
pp. 661-667 ◽  
Author(s):  
Michael H. Madany ◽  
Niel E. West
2016 ◽  
Vol 25 (8) ◽  
pp. 909
Author(s):  
Raphaël D. Chavardès ◽  
Lori D. Daniels

Fire suppression has altered the historical mixed-severity fire regime and homogenised forest structures in Jasper National Park, Canada. We used dendrochronology to reconstruct fire history and assess forest dynamics at 29 sites in the montane forests. Based on fire scars and even-aged post-fire cohorts, we determined 18 sites had mixed-severity fire histories through time, and 11 sites had evidence of high-severity fires only – yielding a mixed-severity fire regime for the study area. Lodgepole pine, hybrid spruce and Douglas-fir established simultaneously after low- and high-severity fires. Regardless of fire history, forest canopies were mixed in composition and subcanopies were strongly dominated by shade-tolerant hybrid spruce. Despite their size, subcanopy trees were similar in age to the canopy trees. Current stand composition and age structures largely reflect the effects of high-severity fires that burned ~110 years ago at 18 of 29 sites. In the absence of fires after 1905, forests have matured simultaneously, homogenising the landscape and resulting in forest structures that are more conducive to high-severity fire than are fires of a range of severities. Proactive fire management is justified to restore fire as a vital ecological process and promote forest resilience by countering the effects of a century of fire suppression.


2016 ◽  
Vol 25 (4) ◽  
pp. 433 ◽  
Author(s):  
Raphaël D. Chavardès ◽  
Lori D. Daniels

Fire suppression has altered the historical mixed-severity fire regime and homogenised forest structures in Jasper National Park, Canada. We used dendrochronology to reconstruct fire history and assess forest dynamics at 29 sites in the montane forests. Based on fire scars and even-aged post-fire cohorts, we determined 18 sites had mixed-severity fire histories through time, and 11 sites had evidence of high-severity fires only – yielding a mixed-severity fire regime for the study area. Lodgepole pine, hybrid spruce and Douglas-fir established simultaneously after low- and high-severity fires. Regardless of fire history, forest canopies were mixed in composition and subcanopies were strongly dominated by shade-tolerant hybrid spruce. Despite their size, subcanopy trees were similar in age to the canopy trees. Current stand composition and age structures largely reflect the effects of high-severity fires that burned ~110 years ago at 18 of 29 sites. In the absence of fires after 1905, forests have matured simultaneously, homogenising the landscape and resulting in forest structures that are more conducive to high-severity fire than are fires of a range of severities. Proactive fire management is justified to restore fire as a vital ecological process and promote forest resilience by countering the effects of a century of fire suppression.


2017 ◽  
Vol 4 ◽  
pp. 99-180 ◽  
Author(s):  
Jeffrey W. Martz ◽  
James I. Kirkland ◽  
Andrew R.C. Milner ◽  
William G. Parker ◽  
Vincent L. Santucci

The Chinle Formation and the lower part of the overlying Wingate Sandstone and Moenave Formation were deposited in fluvial, lacustrine, paludal, and eolian environments during the Norian and Rhaetian stages of the Late Triassic (~230 to 201.3 Ma), during which time the climate shifted from subtropical to increasingly arid. In southern Utah, the Shinarump Member was largely confined to pre-Chinle paleovalleys and usually overprinted by mottled strata. From southeastern to southwestern Utah, the lower members of the Chinle Formation (Cameron Member and correlative Monitor Butte Member) thicken dramatically whereas the upper members of the Chinle Formation (the Moss Back, Petrified Forest, Owl Rock, and Church Rock Members) become erosionally truncated; south of Moab, the Kane Springs beds are laterally correlative with the Owl Rock Member and uppermost Petrified Forest Member. Prior to the erosional truncation of the upper members, the Chinle Formation was probably thickest in a southeast to northwest trend between Petrified Forest National Park and the Zion National Park, and thinned to the northeast due to the lower Chinle Formation lensing out against the flanks of the Ancestral Rocky Mountains, where the thickness of the Chinle is largely controlled by syndepositional salt tectonism. The Gartra and Stanaker Members of the Ankareh Formation are poorly understood Chinle Formation correlatives north of the San Rafael Swell. Osteichthyan fish, metoposaurid temnospondyls, phytosaurids, and crocodylomorphs are known throughout the Chinle Formation, although most remains are fragmentary. In the Cameron and Monitor Butte Members, metoposaurids are abundant and non-pseudopalatine phytosaurs are known, as is excellent material of the paracrocodylomorph Poposaurus; fragmentary specimens of the aetosaurs Calyptosuchus, Desmatosuchus, and indeterminate paratypothoracisins were probably also recovered from these beds. Osteichthyans, pseudopalatine phytosaurs, and the aetosaur Typothorax are especially abundant in the Kane Springs beds and Church Rock Member of Lisbon Valley, and Typothorax is also known from the Petrified Forest Member in Capitol Reef National Park. Procolophonids, doswelliids, and dinosaurs are known but extremely rare in the Chinle Formation of Utah. Body fossils and tracks of osteichthyans, therapsids, crocodylomorphs, and theropods are well known from the lowermost Wingate Sandstone and Moenave Formation, especially from the St. George Dinosaur Discovery Site at Johnson Farm.


2018 ◽  
Author(s):  
Anna Stanczyk ◽  
◽  
Jeffrey R. Moore ◽  
Olivia Kronig ◽  
Brendon J. Quirk ◽  
...  

Fire Ecology ◽  
2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Jan W. van Wagtendonk ◽  
Peggy E. Moore ◽  
Julie L. Yee ◽  
James A. Lutz

Abstract Background The effects of climate on plant species ranges are well appreciated, but the effects of other processes, such as fire, on plant species distribution are less well understood. We used a dataset of 561 plots 0.1 ha in size located throughout Yosemite National Park, in the Sierra Nevada of California, USA, to determine the joint effects of fire and climate on woody plant species. We analyzed the effect of climate (annual actual evapotranspiration [AET], climatic water deficit [Deficit]) and fire characteristics (occurrence [BURN] for all plots, fire return interval departure [FRID] for unburned plots, and severity of the most severe fire [dNBR]) on the distribution of woody plant species. Results Of 43 species that were present on at least two plots, 38 species occurred on five or more plots. Of those 38 species, models for the distribution of 13 species (34%) were significantly improved by including the variable for fire occurrence (BURN). Models for the distribution of 10 species (26%) were significantly improved by including FRID, and two species (5%) were improved by including dNBR. Species for which distribution models were improved by inclusion of fire variables included some of the most areally extensive woody plants. Species and ecological zones were aligned along an AET-Deficit gradient from cool and moist to hot and dry conditions. Conclusions In fire-frequent ecosystems, such as those in most of western North America, species distribution models were improved by including variables related to fire. Models for changing species distributions would also be improved by considering potential changes to the fire regime.


2002 ◽  
Vol 32 (11) ◽  
pp. 2010-2021 ◽  
Author(s):  
Jeanine M Rhemtulla ◽  
Ronald J Hall ◽  
Eric S Higgs ◽  
S Ellen Macdonald

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.


2010 ◽  
Vol 58 (4) ◽  
pp. 300 ◽  
Author(s):  
Jeremy Russell-Smith ◽  
Cameron P. Yates ◽  
Chris Brock ◽  
Vanessa C. Westcott

Few data are available concerning contemporary fire regimes and the responses of fire interval-sensitive vegetation types in semiarid woodland savanna landscapes of northern Australia. For a 10 300 km2 semiarid portion of Gregory National Park, in the present paper we describe (1) components of the contemporary fire regime for 1998–2008, on the basis of assessments derived from Landsat and MODIS imagery, (2) for the same period, the population dynamics, and characteristic fine-fuel loads associated with Acacia shirleyi Maiden (lancewood), an obligate seeder tree species occurring in dense monodominant stands, and (3) the fire responses of woody species, and fine-fuel dynamics, sampled in 41 plots comprising shrubby open-woodland over spinifex hummock grassland. While rain-year (July–June) rainfall was consistently reliable over the study period, annual fire extent fluctuated markedly, with an average of 29% being fire affected, mostly in the latter part of the year under relatively harsh fire-climate conditions. Collectively, such conditions facilitated short fire-return intervals, with 30% of the study area experiencing a repeat fire within 1 year, and 80% experiencing a repeat fire within 3 years. Fine fuels associated with the interior of lancewood thickets were characteristically small (<1 t ha–1). Fine fuels dominated by spinifex (Triodia spp.) were found to accumulate at rates equivalent to those observed under higher-rainfall conditions. Stand boundaries of A. shirleyi faired poorly under prevailing fire regimes over the study period; in 16 plots, juvenile density declined 62%, and adult stem density and basal area declined by 53% and 40%, respectively. Although the maturation (primary juvenile) period of A. shirleyi is incompletely known, assembled growth rate and phenology data indicated that it is typically >10 years. Of 133 woody species sampled, all trees (n = 26), with the exception of A. shirleyi, were resprouters, and 58% of all shrub species (n = 105) were obligate seeders, with observed primary juvenile periods <5 years. Assembled data generally supported observations made from other northern Australian studies concerning the responses of fire-sensitive woody taxa in rugged, sandstone-derived landscapes, and illustrated the enormous challenges facing ecologically sustainable fire management in such settings. Contemporary fire regimes of Gregory National Park are not ecologically sustainable.


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