Post-fire vegetation dynamics of a sagebrush steppe community change significantly over time

Hanna, Sara K.; Fulgham, Kenneth O.

doi:10.3733/ca.v069n01p36

Cited by 42 publications

(27 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Many areas are still susceptible to initial cheatgrass invasion and densification (Miller et al 2011); however, we show a slight downward trend in annual herbaceous cover, possibly due to the fact that 50-60% of the historic sagebrush steppe range either possessed an understory of exotic annual grass (i.e., cheatgrass) or has already been converted to an annual grassland (West 2000). Unburned area differences are consistent with ecological expectations, in that shrub and sagebrush cover is increasing, driven largely by secondary succession (Hanna and Fulgham 2015), while decreases in the study area overall are mostly driven by burns , Shi et al 2018, due to the slow recovery of sagebrush (Baker 2011, Bukowski andBaker 2013). Moreover, when looking at only burned areas, annual herbaceous cover increased at a rate of 0.03% per decade, as expected in burned areas (Hanna and Fulgham 2015).…”

Section: Temporal Trendssupporting

confidence: 83%

“…While Shi et al (2018) reported little trend in litter cover, we report a significant decrease of À0.02% per decade. Moreover, when looking at only burned areas, annual herbaceous cover increased at a rate of 0.03% per decade, as expected in burned areas (Hanna and Fulgham 2015). Indeed, reported that most significant trends in cheatgrass performance from 2000 to 2010 in the Northern Great Basin were negative.…”

Section: Temporal Trendsmentioning

confidence: 56%

“…Research in the Great Basin has shown that 0% shrub and sagebrush cover is a reasonable assumption in these recent burns (Hanna and Fulgham 2015). Specifically, we selected 30,000 random points within the combined extent of moderate and severe burns of each target year and the preceding 4 yr and assigned a training data value of 0% shrub and sagebrush cover to each.…”

Section: Training Datamentioning

confidence: 99%

See 2 more Smart Citations

Long‐term trajectories of fractional component change in the Northern Great Basin, USA

et al. 2019

View full text Add to dashboard Cite

The need to monitor change in sagebrush steppe is urgent due to the increasing impacts of climate change, shifting fire regimes, and management practices on ecosystem health. Remote sensing provides a cost-effective and reliable method for monitoring change through time and attributing changes to drivers. We report an automated method of mapping rangeland fractional component cover over a large portion of the Northern Great Basin, USA, from 1986 to 2016 using a dense Landsat imagery time series. Our method improved upon the traditional change vector method by considering the legacy of change at each pixel. We evaluate cover trends stratified by climate bin and assess spatial and temporal relationships with climate variables. Finally, we statistically evaluate the minimum time density needed to accurately characterize temporal patterns and relationships with climate drivers. Over the 30-yr period, shrub cover declined and bare ground increased. While few pixels had >10% cover change, a large majority had at least some change. All fractional components had significant spatial relationships with water year precipitation (WYPRCP), maximum temperature (WYTMAX), and minimum temperature (WYTMIN) in all years. Shrub and sagebrush cover in particular respond positively to warming WYTMIN, resulting from the largest increases in WYTMIN being in the coolest and wettest areas, and respond negatively to warming WYTMAX because the largest increases in WYTMAX are in the warmest and driest areas. The trade-off of lowering temporal density against removing cloud-contaminated years is justified as temporal density appears to have only a modest impact on trends and climate relationships until n ≤ 6, but multi-year gaps are proportionally more influential. Gradual change analysis is likely to be less sensitive to n than abrupt change. These data can be used to answer critical questions regarding the influence of climate change and the suitability of management practices.

show abstract

Section: Temporal Trendssupporting

confidence: 83%

Section: Temporal Trendsmentioning

confidence: 56%

Section: Training Datamentioning

confidence: 99%

See 1 more Smart Citation

Long‐term trajectories of fractional component change in the Northern Great Basin, USA

et al. 2019

View full text Add to dashboard Cite

show abstract

“…7). The relatively rapid rebound of certain herbaceous functional groups is consistent with work showing that annual and perennial herbaceous species may recover within a few years after burning (Miller et al 2013, Hanna and Fulgham 2015, Shinneman and McIlroy 2016. S2).…”

Section: Fire As a Driver Of Vegetation Changesupporting

confidence: 82%

Pre‐fire vegetation drives post‐fire outcomes in sagebrush ecosystems: evidence from field and remote sensing data

et al. 2019

View full text Add to dashboard Cite

Understanding the factors that influence vegetation responses to disturbance is important because vegetation is the foundation of food resources, wildlife habitat, and ecosystem properties and processes. We integrated vegetation cover data derived from field plots and remotely sensed Landsat images in two focal areas over a 37-yr period to investigate how historical changes to community composition influence contemporary responses of vegetation to fire in sagebrush ecosystems in the Great Basin. Our objectives were (1) to quantify the magnitude and direction of change in the cover of native and exotic plant functional groups in relation to their exposure to fire; (2) to relate plant community changes to their historical composition, exposure to fire, and environmental conditions; and (3) to test for consistency of trends revealed by vegetation cover data derived from field plots and Landsat images. Historical (1979Historical ( -1981 field data originated from 298 locations, Landsat-derived data and contemporary (2011-2016) field data originated from 448 locations, and an expanded set of locations were included in some analyses of Landsat-derived data. We found that areas burned by fire since the 1980s had higher annual herbaceous cover than unburned areas both historically and contemporarily. Models revealed a significant interaction between historical community composition and exposure to fire, which suggests that plots with historically high herbaceous cover were more susceptible to burning. Trends revealed by field and Landsat-derived cover data were only partially consistent, potentially due in part to methods used to predict cover values from Landsat images, and the time period over which each data set was collected. Our results suggest that burned areas historically occupied by sagebrush-dominated plant communities may have been invaded by exotic annuals prior to burning, possibly because of prior land uses, and after burning, have now transitioned to a persistent herbaceous-dominated state. This type of state transition has important consequences for forage quality, wildlife habitat, soil nutrients, and future disturbances, such as drought and wildfire.

show abstract

“…) and should be prevented from burning whenever possible, while higher elevation Mountain big sagebrush ( A. tridentata ssp. vaseyana ) ecosystems may still recover naturally (Hanna and Fulgham ) or with restoration by seeding (Knutson et al. ).…”

Section: Introductionmentioning

confidence: 99%

Repeated fires reduce plant diversity in low‐elevation Wyoming big sagebrush ecosystems (1984–2014)

Mahood

Balch

2019

Ecosphere

View full text Add to dashboard Cite

Sagebrush is one of the most imperiled ecosystems in western North America, having lost about half of its original 62 million hectare extent. Annual grass invasions are known to be increasing wildfire occurrence and burned area, but the lasting effects (greater than five years post‐fire) that the resulting reburns have on these plant communities are unclear. We created a fire history atlas from 31 yr (1984–2014) of Landsat‐derived fire data to sample along a fire frequency gradient (zero to three fires) in an area of northern Nevada that has experienced frequent fire in this time period. Thirty‐two percent of our study area (13,000 km2) burned in large fires (over 404 ha) at least once, 7% burned twice, and 2% burned three or more times. We collected plant abundance data at 28 plots (N = 7 per fire frequency), with an average time since fire of 17 yr. We examined fire's effect on plant diversity using species accumulation curves, alpha diversity (Shannon's dominance, Pielou's evenness, and number of species), and beta diversity (Whittaker, Simpson, and Z indexes). For composition, we used non‐metric multidimensional scaling. We then used PERMANOVA models to examine how disturbance history, temperature, precipitation, and aridity around the time of the fire affected subsequent community composition and diversity. One fire fundamentally changed community composition and reduced species richness, and each subsequent fire reduced richness further. Alpha diversity decreased after one fire. Beta diversity declined after the third fire. Cover of exotics was 10% higher in all burned plots, and native cover was 20% lower than in unburned plots, regardless of frequency. PERMANOVA models showed fire frequency and antecedent precipitation as the strongest predictors of beta diversity, while time since fire and vapor pressure deficit for the year of the fire were the strongest predictors of community composition. Given that a single fire has such a marked effect on species composition, and repeated fires reduce richness and beta diversity, we suggest that in lower elevation big sagebrush systems fire should be minimized as much as possible, perhaps even prescribed fire. Restoration efforts should be focused on timing with wet years on cooler, wetter sites.

show abstract

Post-fire vegetation dynamics of a sagebrush steppe community change significantly over time

Cited by 42 publications

References 14 publications

Long‐term trajectories of fractional component change in the Northern Great Basin, USA

Long‐term trajectories of fractional component change in the Northern Great Basin, USA

Pre‐fire vegetation drives post‐fire outcomes in sagebrush ecosystems: evidence from field and remote sensing data

Repeated fires reduce plant diversity in low‐elevation Wyoming big sagebrush ecosystems (1984–2014)

Contact Info

Product

Resources

About