Wildland fire effects on understory plant communities in two fire-prone forests

2008 ◽  
Vol 38 (1) ◽  
pp. 133-142 ◽  
Author(s):  
Daniel C. Laughlin ◽  
Peter Z. Fulé
Keyword(s):  
Species Richness ◽  
Ponderosa Pine ◽  
Wildland Fire ◽  
Plant Cover ◽  
Plant Species Richness ◽  
Fire Effects ◽  
Surface Fire ◽  
Total Species Richness ◽  
Understory Plant ◽  
Understory Plant Communities

Our understanding of wildland fire effects on understory plant communities is limited because of a lack of repeated measurements before and after lightning-ignited fires. We examined vegetation responses to a surface fire in a ponderosa pine forest and a mixed-severity fire in a spruce–fir–aspen forest using before–after, control–impact (BACI) study designs. We hypothesized that the surface fire would stimulate plant species richness and minimally alter community composition, but that the mixed-severity fire would decrease richness and significantly alter composition. In ponderosa pine forests, total species richness and plant cover increased slightly because of annual and biennial forb and grass establishment in soils where duff layers were reduced by the surface fire. In spruce–fir–aspen forests, total species richness and plant cover were similar in burned and unburned forests after 2 years, although annual and biennial forbs and graminoids increased significantly in the burned area. Plant community composition was altered by both fires. Wildfires may indirectly influence the understory plant community through the mediating effects of overstory basal area and litter depth. Fire effects on plant species richness and cover were weaker than effects due to environmental factors. Managers should anticipate increases in both native and non-native ruderal species following landscape-scale fires.

Impacts of erosion control treatments on native vegetation recovery after severe wildfire in the Eastern Cascades, USA

2010 ◽  
Vol 19 (4) ◽  
pp. 490 ◽  
Author(s):  
Erich K. Dodson ◽  
David W. Peterson ◽  
Richy J. Harrod
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Native Species ◽  
Plant Cover ◽  
Plant Species Richness ◽  
Tree Regeneration ◽  
Vegetation Recovery ◽  
Native Vegetation ◽  
Individual Plant ◽  
Native Plant

Slope stabilisation treatments like mulching and seeding are used to increase soil cover and reduce runoff and erosion following severe wildfires, but may also retard native vegetation recovery. We evaluated the effects of seeding and fertilisation on the cover and richness of native and exotic plants and on individual plant species following the 2004 Pot Peak wildfire in Washington State, USA. We applied four seeding and three fertilisation treatments to experimental plots at eight burned sites in spring 2005 and surveyed vegetation during the first two growing seasons after fire. Seeding significantly reduced native non-seeded species richness and cover by the second year. Fertilisation increased native plant cover in both years, but did not affect plant species richness. Seeding and fertilisation significantly increased exotic cover, especially when applied in combination. However, exotic cover and richness were low and treatment effects were greatest in the first year. Seeding suppressed several native plant species, especially disturbance-adapted forbs. Fertilisation, in contrast, favoured several native understorey plant species but reduced tree regeneration. Seeding, even with native species, appears to interfere with the natural recovery of native vegetation whereas fertilisation increases total plant cover, primarily by facilitating native vegetation recovery.

Hybridization among foundation tree species influences the structure of associated understory plant communities

Botany ◽  
2011 ◽  
Vol 89 (3) ◽  
pp. 165-174 ◽  
Author(s):  
L. J. Lamit ◽  
T. Wojtowicz ◽  
Z. Kovacs ◽  
S. C. Wooley ◽  
M. Zinkgraf ◽  
...  
Keyword(s):  
Species Richness ◽  
Plant Communities ◽  
Structural Equation ◽  
Evolutionary Ecology ◽  
Experimental System ◽  
Common Garden ◽  
Equation Modeling ◽  
Understory Plant ◽  
Tree Genetics ◽  
Understory Plant Communities

Understanding how genetic identity influences community structure is a major focus in evolutionary ecology, yet few studies examine interactions among organisms in the same trophic level within this context. In a common garden containing trees from a hybrid system (Populus fremontii S. Wats. × Populus angustifolia James), we tested the hypothesis that the structure of establishing understory plant communities is influenced by genetic differences among trees and explored foliar condensed tannins (CTs) and photosynthetically active radiation (PAR) as mechanisms. Several findings support our hypothesis: (i) Understory biomass and cover increase along the genetic gradient from P. angustifolia to P. fremontii. (ii) Along the same hybridization gradient, species richness decreases and species composition shifts. (iii) Populus foliar CT concentrations and PAR decrease from P. angustifolia to P. fremontii. (iv) Understory species richness increases with foliar CTs; however, biomass, cover, and composition show no relationship with CTs, and no understory variables correlate with PAR. (v) Structural equation modeling suggests that foliar CTs are a primary mechanism linking overstory tree genetics with understory richness. Using an experimental system dominated by naturally colonizing exotic species, this study demonstrates that a genetic gradient created by tree hybridization can influence understory plants.

scholarly journals Plant Species Richness in Multiyear Wet and Dry Periods in the Chihuahuan Desert

Climate ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 130
Author(s):  
Debra P. C. Peters ◽  
Heather M. Savoy ◽  
Susan Stillman ◽  
Haitao Huang ◽  
Amy R. Hudson ◽  
...  
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Chihuahuan Desert ◽  
Extreme Rainfall ◽  
Plant Species Richness ◽  
Ecosystem Dynamics ◽  
Creosote Bush ◽  
Extreme Precipitation Events ◽  
Total Species Richness ◽  
C3 Species

In drylands, most studies of extreme precipitation events examine effects of individual years or short-term events, yet multiyear periods (>3 y) are expected to have larger impacts on ecosystem dynamics. Our goal was to take advantage of a sequence of multiple long-term (4-y) periods (dry, wet, average) that occurred naturally within a 26-y time frame to examine responses of plant species richness to extreme rainfall in grasslands and shrublands of the Chihuahuan Desert. Our hypothesis was that richness would be related to rainfall amount, and similar in periods with similar amounts of rainfall. Breakpoint analyses of water-year precipitation showed five sequential periods (1993–2018): AVG1 (mean = 22 cm/y), DRY1 (mean = 18 cm/y), WET (mean = 30 cm/y), DRY2 (mean = 18 cm/y), and AVG2 (mean = 24 cm/y). Detailed analyses revealed changes in daily and seasonal metrics of precipitation over the course of the study: the amount of nongrowing season precipitation decreased since 1993, and summer growing season precipitation increased through time with a corresponding increase in frequency of extreme rainfall events. This increase in summer rainfall could explain the general loss in C3 species after the wet period at most locations through time. Total species richness in the wet period was among the highest in the five periods, with the deepest average storm depth in the summer and the fewest long duration (>45 day) dry intervals across all seasons. For other species-ecosystem combinations, two richness patterns were observed. Compared to AVG2, AVG1 had lower water-year precipitation yet more C3 species in upland grasslands, creosotebush, and mesquite shrublands, and more C4 perennial grasses in tarbush shrublands. AVG1 also had larger amounts of rainfall and more large storms in fall and spring with higher mean depths of storm and lower mean dry-day interval compared with AVG2. While DRY1 and DRY2 had the same amount of precipitation, DRY2 had more C4 species than DRY1 in creosote bush shrublands, and DRY1 had more C3 species than DRY2 in upland grasslands. Most differences in rainfall between these periods occurred in the summer. Legacy effects were observed for C3 species in upland grasslands where no significant change in richness occurred from DRY1 to WET compared with a 41% loss of species from the WET to DRY2 period. The opposite asymmetry pattern was found for C4 subdominant species in creosote bush and mesquite shrublands, where an increase in richness occurred from DRY1 to WET followed by no change in richness from WET to DRY2. Our results show that understanding plant biodiversity of Chihuahuan Desert landscapes as precipitation continues to change will require daily and seasonal metrics of rainfall within a wet-dry period paradigm, as well as a consideration of species traits (photosynthetic pathways, lifespan, morphologies). Understanding these relationships can provide insights into predicting species-level dynamics in drylands under a changing climate.

scholarly journals Patterns of plant species richness along the drawdown zone of the Three Gorges Reservoir 5 years after submergence

2017 ◽  
Vol 75 (10) ◽  
pp. 2299-2308 ◽  
Author(s):  
Sun Rong ◽  
Liang Shaomin ◽  
Qiu Shike ◽  
Deng Wei
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Soil Type ◽  
Three Gorges Reservoir ◽  
Plant Species Richness ◽  
Three Gorges ◽  
The Three Gorges Reservoir ◽  
The Three Gorges ◽  
Total Species Richness ◽  
Drawdown Zone

This study was conducted to understand the patterns of plant species richness in the Three Gorges Reservoir after 5 years after 175 m submergence. We hypothesized that hygrophyte and xerophyte species would show different species richness patterns, which was tested by collecting species composition and environmental variable data in 50 m long and 5 m wide transects in the drawdown zone from 145 m to 180 m. Xerophyte species richness (XSR) was highest in the middle of the drawdown zone, whereas hygrophyte species showed a continuous downward trend from 145 m to 180 m. Correlation analyses showed that the flooding period was significantly negatively correlated with the total species richness (TSR), XSR, and hygrophyte species richness (HSR). The TSR and XSR showed a significant positive correlation with soil type and a significant negative correlation with available K. HSR was significantly correlated with soil type and negatively correlated with ammonium N.

Fire effects on shoot growth characteristics of ponderosa pine in Colorado

1983 ◽  
Vol 13 (4) ◽  
pp. 620-625 ◽  
Author(s):  
James G. Wyant ◽  
Richard D. Laven ◽  
Philip N. Omi
Keyword(s):  
Ponderosa Pine ◽  
Shoot Growth ◽  
Fire Effects ◽  
Growth Characteristics ◽  
Growth Potential ◽  
Fire Damage ◽  
Fall Season ◽  
Surface Fire ◽  
Bud Formation ◽  
The Impact

The impact of fire damage on the shoot growth potential of 36 branches on each of nine ponderosa pine (Pinusponderosa Laws.) trees was evaluated after a fall season prescribed surface fire. In the first season after burning, mean fascicle lengths and bud sizes (length and diameter) were greater on trees which received underburning treatment than on unburned trees. No treatment effect was observed on shoot lengths, needle numbers, or fascicle numbers, characters determined in the season of bud formation.

Ecological impacts of wheat seeding after a Sierra Nevada wildfire

2004 ◽  
Vol 13 (1) ◽  
pp. 73 ◽  
Author(s):  
Jon E. Keeley
Keyword(s):  
Species Richness ◽  
Sierra Nevada ◽  
Ponderosa Pine ◽  
Seedling Recruitment ◽  
Vascular Plant ◽  
Ecological Impact ◽  
Ground Surface ◽  
Ecological Impacts ◽  
Total Species Richness ◽  
Giant Sequoia

The Highway Fire burned 1680 ha of mixed ponderosa pine–oak–chaparral in the newly created Giant Sequoia National Monument and the adjacent Sequoia National Forest of Fresno County, California in August 2001. The USDA Forest Service Burned Area Emergency Rehabilitation (BAER) program recommended that portions of the burned forest be seeded with a non-persistent variety of wheat at a density of 157 kg ha–1 (140 lb/ac). The present study compared the vascular plant diversity and cover in seeded and unseeded parts of this burn to evaluate the ecological impact of seeding an alien grass. In the first post-fire growing season, the natural regeneration of unseeded control sites averaged ~55% ground surface covered. Wheat seeding enhanced the ground cover, averaging 95% ground surface cover. Wheat was the dominant species on the seeded sites, comprising 67% of the total cover. Dominance–diversity curves were markedly affected by the seeding and indicated a disruption in the natural ecological structure of these communities. On seeded sites, wheat dominated and all other species were poorly represented whereas, on unseeded control sites, there was a more equitable distribution of species. Correlated with the wheat cover was a significant decrease in species richness at all scales examined. Total species richness was reduced from 152 species across all unseeded sites to 104 species on all seeded sites. Average species richness, at scales from 1 to 1000 m2, was 30–40% lower on seeded sites. Species most strongly inhibited were post-fire endemics whose lifecycle is restricted to immediate post-fire environments. Seeded sites had fewer alien species than unseeded sites; however, this may not have any lasting effect since other studies show the primary alien threat is not in the first post-fire year. Seeding was also associated with an order of magnitude drop in Pinus ponderosa seedling recruitment and, coupled with the massive thatch still remaining on the site, it is likely that recruitment will be inhibited in subsequent years.

Is there a middle way between permanent plots and chronosequences?

2008 ◽  
Vol 38 (12) ◽  
pp. 3133-3138 ◽  
Author(s):  
Randall W. Myster ◽  
Michael P. Malahy
Keyword(s):  
Species Richness ◽  
Structural Parameters ◽  
Plant Cover ◽  
Permanent Plots ◽  
Vegetation Changes ◽  
Middle Way ◽  
Total Species Richness ◽  
Luquillo Mountains ◽  
Total Plant ◽  
Total Species

Although permanent plots have proven critical to studies of vegetation dynamics, their logistic limitations have led to the wide use of chronosequences as an alternative. Here, we test whether or not an approach combining permanent plots and chronosequences could be used successfully to accurately predict the vegetation changes that one would see in permanent plots in the same area. We used plot data from five pastures in the Luquillo Mountains of Puerto Rico, USA, and found that (i) for species composition and abundance, the five pastures did not form a single trajectory or show any convergence, (ii) for successional rate, there was a general decrease with time since abandonment for most pastures, but that decrease was not monotonic and one pasture of the five had no decrease at all, and (iii) total species richness and total plant cover showed pastures that lined up well by age, forming almost a single trajectory with little variation. We conclude that the utility of using chronosequences either alone or with permanent plots depends largely on the parameter under study with broad structural parameters, such as total species richness and total plant cover, performing best.

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