scholarly journals Wildfire and topography drive woody plant diversity in a Sky Island mountain range in the Southwest USA

2021 ◽  
Author(s):  
Andrew Barton ◽  
Helen Poulos
Keyword(s):  
Species Diversity ◽  
Plant Species ◽  
Woody Plant ◽  
Fire Severity ◽  
Alpha Diversity ◽  
Fire Regimes ◽  
Mountain Range ◽  
Gamma Diversity ◽  
In Fire ◽  
The Impact

Aim: Drastic changes in fire regimes are altering plant communities, inspiring ecologists to better understand the relationship between fire and plant species diversity. We examined the impact of a 2011 megafire on woody plant species diversity in an arid mountain range in southern Arizona, USA. We tested recent fire-diversity hypotheses by addressing the impact of the fire severity, fire variability, historic fire regimes, and topography on diversity. Location: Chiricahua National Monument, Chiricahua Mountains, Arizona. USA., part of the Sky Islands of the US-Mexico borderlands. Taxon: Woody plant species. Methods: We sampled woody plant diversity in 138 plots before (2002-2003) and after (2017-2018) the 2011 Horseshoe Two Megafire in three vegetation types and across fire severity and topographic gradients. We calculated gamma, beta, and alpha diversity and examined changes over time in burned vs. unburned plots and the shapes of the relationships of diversity with fire severity and topography. Results: Alpha species richness declined and beta and gamma diversity increased in burned but not unburned plots. Fire-induced enhancement of gamma diversity was confined to low fire severity plots. Alpha diversity did not exhibit a clear continuous relationship with fire severity. Beta diversity was enhanced by fire severity variation among plots and increased with fire severity up to very high diversity, where it declined slightly. Main Conclusions: The results reject the intermediate disturbance hypothesis for alpha diversity but weakly support it for gamma diversity. Spatial variation in fire severity promoted variation among plant assemblages, supporting the pyrodiversity hypothesis. Long-term drought probably amplified fire-driven diversity changes. Despite the apparent benign impact of the fire on diversity, the replacement of two large conifer species with shrubs signals the potential loss of functional diversity, emphasizing the importance of intervention to direct the transition to a novel vegetation mosaic.

scholarly journals Relation between plant species diversity and landscape variables in Central-European dry grassland fragments and their successional derivates

2017 ◽  
Vol 76 (2) ◽  
pp. 111-119
Author(s):  
Igor Paušič ◽  
Danijel Ivajnšič ◽  
Mitja Kaligarič ◽  
Nataša Pipenbaher
Keyword(s):  
Species Diversity ◽  
Plant Species ◽  
Alpha Diversity ◽  
Shape Index ◽  
Plant Species Diversity ◽  
Lower Altitude ◽  
Dry Grassland ◽  
Central European ◽  
Landscape Variables ◽  
Habitat Specialists

AbstractA systematic field survey of an area of 843 ha in the traditional Central-European agricultural landscape of Goričko Nature Park in Slovenia revealed 80 fragments of dry semi-natural grasslands. Vascular plant species diversity was studied in relation to landscape variables and to threat (Slovenian red-listed species). Our results show that fragment size does not affect plant species diversity. In addition, fragment shape index is not related to Alpha diversity. Higher Alpha diversity was observed for abandoned grassland fragments. The lowest Alpha diversity was perceived on more mesic fragments, where habitat specialists are much scarcer. It was confirmed that the highest diversity of specialists are in the driest fragments, both still mowed and abandoned. With an increase in the number of distinctly different bordering habitat types, the total number of species per fragment generally does not increase, except in the case of those fragments that are already in different succession stages. Abandoned and typical dry grasslands are associated with a higher number of bordering habitats. Typical dry grassland fragments and abandoned ones, which probably derived mostly from drier (less productive) grasslands, are found on lower altitude and have a lower shape index. Habitat specialistsSedum sexangulare, Polygala vulgarisandSpiranthes spiralishave higher frequency in fragments with a lower shape index. This means that these oligotrophic specialists occur in smaller fragments. ButOrchis moriohas higher frequencies of occurrence on polygons with a higher shape index, which confirms the observation that this species occurs in larger and more irregular fragments, as well as close to houses and fields and along the roads.

scholarly journals Can trophic rewilding reduce the impact of fire in a more flammable world?

2018 ◽  
Vol 373 (1761) ◽  
pp. 20170443 ◽  
Author(s):  
Christopher N. Johnson ◽  
Lynda D. Prior ◽  
Sally Archibald ◽  
Helen M. Poulos ◽  
Andrew M. Barton ◽  
...  
Keyword(s):  
Fire Regimes ◽  
Ground Vegetation ◽  
Litter Layer ◽  
Theme Issue ◽  
Large Herbivores ◽  
Plant Matter ◽  
The World ◽  
Large Animals ◽  
In Fire ◽  
The Impact

Large vertebrates affect fire regimes in several ways: by consuming plant matter that would otherwise accumulate as fuel; by controlling and varying the density of vegetation; and by engineering the soil and litter layer. These processes can regulate the frequency, intensity and extent of fire. The evidence for these effects is strongest in environments with intermediate rainfall, warm temperatures and graminoid-dominated ground vegetation. Probably, extinction of Quaternary megafauna triggered increased biomass burning in many such environments. Recent and continuing declines of large vertebrates are likely to be significant contributors to changes in fire regimes and vegetation that are currently being experienced in many parts of the world. To date, rewilding projects that aim to restore large herbivores have paid little attention to the value of large animals in moderating fire regimes. Rewilding potentially offers a powerful tool for managing the risks of wildfire and its impacts on natural and human values. This article is part of the theme issue ‘Trophic rewilding: consequences for ecosystems under global change’.

scholarly journals Reconstructing burnt area during the Holocene: an Iberian case study

2021 ◽  
Author(s):  
Yicheng Shen ◽  
Luke Sweeney ◽  
Mengmeng Liu ◽  
Jose Antonio Lopez Saez ◽  
Sebastián Pérez-Díaz ◽  
...  
Keyword(s):  
Fire Regimes ◽  
Weighted Averaging ◽  
Pollen Data ◽  
Burnt Area ◽  
The Holocene ◽  
Quantitative Estimates ◽  
In Fire ◽  
The Impact ◽  
Pollen Records

Abstract. Charcoal accumulated in lake, bog or other anoxic sediments through time has been used to document the geographical patterns in changes in fire regimes. Such reconstructions are useful to explore the impact of climate and vegetation changes on fire during periods when the human influence was less prevalent than today. However, charcoal records only provide semi-quantitative estimates of change in biomass burning. Here we derive quantitative estimates of burnt area from vegetation data in two stages. First, we relate the modern charcoal abundance to burnt area using a conversion factor derived from a generalized linear model of burnt area probability based on eight environmental predictors. Then, we establish the relationship between fossil pollen assemblages and burnt area using Tolerance-weighted Weighted Averaging Partial Least-Squares with sampling frequency correction (fxTWA-PLS). We test this approach using the Iberian Peninsula as a case study because it is a fire-prone region with abundant pollen and charcoal records covering the Holocene. We derive the vegetation-burnt area relationship using the 29 records that have both modern and fossil charcoal and pollen data, and then reconstruct palaeo-burnt area for the 114 records with Holocene pollen records. The pollen data predict charcoal abundances through time relatively well (R2 = 0.47) and the changes in reconstructed burnt area are synchronous with known climate changes through the Holocene. This new method opens up the possibility of reconstructing changes in fire regimes quantitatively from pollen records, which are far more numerous than charcoal records.

Mapping fire regime ecoregions in California

2020 ◽  
Vol 29 (7) ◽  
pp. 595 ◽  
Author(s):  
Alexandra D. Syphard ◽  
Jon E. Keeley
Keyword(s):  
Fire Regime ◽  
Fire Severity ◽  
Fire Regimes ◽  
Unsupervised Classification ◽  
Fire Frequency ◽  
The State ◽  
Reduction Strategies ◽  
Lower Variability ◽  
Fire Characteristics ◽  
In Fire

The fire regime is a central framing concept in wildfire science and ecology and describes how a range of wildfire characteristics vary geographically over time. Understanding and mapping fire regimes is important for guiding appropriate management and risk reduction strategies and for informing research on drivers of global change and altered fire patterns. Most efforts to spatially delineate fire regimes have been conducted by identifying natural groupings of fire parameters based on available historical fire data. This can result in classes with similar fire characteristics but wide differences in ecosystem types. We took a different approach and defined fire regime ecoregions for California to better align with ecosystem types, without using fire as part of the definition. We used an unsupervised classification algorithm to segregate the state into spatial clusters based on distinctive biophysical and anthropogenic attributes that drive fire regimes – and then used historical fire data to evaluate the ecoregions. The fire regime ecoregion map corresponded well with the major land cover types of the state and provided clear separation of historical patterns in fire frequency and size, with lower variability in fire severity. This methodology could be used for mapping fire regimes in other regions with limited historical fire data or forecasting future fire regimes based on expected changes in biophysical characteristics.

Fire and its impact on avian population dynamics

1997 ◽  
Vol 3 (3) ◽  
pp. 206 ◽  
Author(s):  
G. Barry Baker ◽  
E. Belinda Dettmann ◽  
Stephen J. Wilson
Keyword(s):  
Population Size ◽  
Fire Regimes ◽  
Long Term Study ◽  
Sclerophyll Forest ◽  
In Fire ◽  
Avian Populations ◽  
The Impact ◽  
Term Monitoring ◽  
Probability Of Capture

Survival rate, population size, recruitment and probability of capture, derived from a long-term study of 20 passerine species in wet sclerophyll forest near Canberra, were used to measure the impact of a high intensity wildfire which burnt 70% of the study area. The wildfire significantly affected the population size of 13 species for a period of up to six years following the fire. Survival and recruitment were the least sensitive measures of impact and indicated a significant response to fire for only 2 of 10 species. We detected measurable effects of the fire for 17 of the 20 species studied. Many of these species had returned to prefire levels within three years, but for nine species the effects were still apparent six years later. Mark-recapture methodology provides an effective way of measuring the impact of fire regimes in forest environments. Long-term monitoring programmes should be established in fire-prone forest environments to contribute toward our understanding of fire, and its effect on avian populations. Such programmes have resource implications and researchers are urged to encourage the participation of the amateur bird banding community to contribute to such projects.

Using bioregional variation in fire history and fire response attributes as a basis for managing threatened flora in a fire-prone Mediterranean climate biodiversity hotspot

2018 ◽  
Vol 66 (2) ◽  
pp. 134 ◽  
Author(s):  
Erica Shedley ◽  
Neil Burrows ◽  
Colin J. Yates ◽  
David J. Coates
Keyword(s):  
Plant Species ◽  
Threatened Species ◽  
Fire History ◽  
Fire Regimes ◽  
Biodiversity Hotspot ◽  
Fire Response ◽  
Relative Level ◽  
Threatened Plant ◽  
Threatened Plant Species ◽  
In Fire

Inappropriate fire-regimes brought about by patterns of human settlement and land-use threaten plant diversity in Mediterranean-type climate (MTC) regions. In south-west Western Australia (SWWA), where there are many threatened plant species distributed across a range of human-modified landscapes, there is a need for approaches to identify where the threat is greatest. This requires knowledge of contemporary fire regimes, how they vary across landscapes, and the sensitivity of threatened species to these regimes. Currently, this information is lacking, and this limits strategic fire management. In this study we compiled fire response information for SWWA’s threatened plant species and undertook a bioregional assessment of variation in fire interval over the last 40 years. We determined the fire response traits of 242 (60%) of the region’s 401 extant threatened species. Over half of the 242 species were obligate seeders and will therefore have population dynamics particularly sensitive to fire interval. Our study highlights large differences in fire interval across nine bioregions in SWWA. The differences were greatest for the heavily cleared and fragmented bioregions compared with more continuously vegetated bioregions. We discuss how variations in the frequency of fire life-history traits and fire interval interact to determine the nature and relative level of threat posed by fire in these landscapes. Survival of many populations of threatened flora in this biodiversity hotspot will depend on developing appropriate fire regimes that match the regeneration requirements of each species.

scholarly journals Quantitative analysis, distributional pattern and species diversity of woody plant species of Lamberi Forest Range, Rajouri, J&K, India

2018 ◽  
Vol 10 (1) ◽  
pp. 522-527
Author(s):  
Jyoti Sharma ◽  
Anil K. Raina
Keyword(s):  
Quantitative Analysis ◽  
Species Diversity ◽  
Plant Species ◽  
Woody Plant ◽  
Diversity Indices ◽  
Distributional Pattern ◽  
Importance Value Index ◽  
Importance Value ◽  
Pinus Roxburghii ◽  
Woody Plant Species

Quantitative analysis, distributional pattern and species diversity of woody plant species of Lamberi Range of Rajouri Forest division, J&K, has been carried out by laying 50 quadrats (10m X 10m size) for trees and 100 quadrats (5m X 5m size) for shrubs. Various phytosociological parameters like frequency, density, abundance, importance value index IVI and diversity indices for trees and shrubs has been used to reveal the plant community structure of the area. The abundance to frequency ratio (A/F) for different species was determined to assess the distribution pattern of the species (regular <0.025, random 0.025-0.05 and contagious >0.05) which indicated the contagious distribution for all the species. Survey of the area revealed presence of 63 woody plant species from the study area comprising of 43 trees and 20 shrubs. Pinus roxburghii (IVI 49.7, Abundance 81.1) and Carissa opaca (IVI 81.12 abundance 7.05) have been recorded as the dominant tree and shrub, respectively, of the area. The computation of diversity indices showed that species richness and evenness i.e Shannon- Weiner’s, Margalef’s and Menhinick’s remained high for trees and low for shrubs. Simpson’s index of dominance was also high for trees. Species which needs priorities for conservation and protection and also required to be monitored have also been highlighted.

scholarly journals Effects of Exotic Plantation Expansion and Management Intervention on Woody Plant Species Diversity, Regeneration and Soil Seed Bank in Tarmaber District, Ethiopia

2021 ◽  
Author(s):  
Melese Bekele Nigussie ◽  
Dessie Assefa Assefa ◽  
Yohannis Gebremariam Gebremariam
Keyword(s):  
Species Diversity ◽  
Plant Species ◽  
Seed Bank ◽  
Woody Plant ◽  
Soil Seed Bank ◽  
Natural Forest ◽  
Forest Types ◽  
Plantation Forest ◽  
Woody Plant Species ◽  
Management Intervention

Abstract This study was carried out in Tarmaber district north shewa zone Ethiopia to determine the effect of plantation forest with management intervention on woody plant species diversity, regeneration and soil seed bank species composition in five different forest types, which are adjacent natural forest, managed Cupressus lusitanica, unmanaged C. lusitanica, managed Eucalyptus globules and not managed E. globules plantation forests. A total of 75 circular sample plots of 314 m2 were established along a transect lines. Soil seed bank analysis was done from soil samples collected in each of the plots (225 samples) to examine the similarity between the soil seed bank and aboveground flora. Different diversity index and ANOVA was used in SPSS software for analysis. The result showed that a total of 51 woody plant species was recorded in adjacent natural forest (41), managed C. lusitanica (27), not managed C. lusitanica (9), managed E. globules (22) and not managed E. globules (13) species. Regeneration of seedlings were 3538, 5567, 707, 1462 and 2524 mean stems ha− 1 for natural forest, managed C. lusitanica, not managed C. lusitanica, managed E. globules and not managed E. globules respectively. Unmanaged C. lusitanica plantations had significantly lower densities of mature tree stems ha− 1 as compared to managed C. lusitanica, managed E. globules and adjacent natural forest (F = 14.03, p < 0.05).Similarly in terms of sapling density ha− 1 unmanaged C. lusitanica was significantly lower from other forest types (F = 7.37, p < 0.05). However managed C. lusitanica had significantly higher seedling regeneration (stem density ha− 1) than other plantation and adjacent natural forests (F = 16.11, p < 0.05). Generally mean stem densities including tree, sapling and seedling of woody species among different forest types managed C. lusitanica was significantly higher among different forest types (F = 13.01, p < 0.05). From the soil seed bank a total of 22 plant species (20 native and 2 exotic) species were recovered. In different forest types the number of species recorded was in adjacent natural forest (19), managed C. lusitanica (11), unmanaged C. lusitanica (4), managed E. globules (7) and unmanaged E. globules (5). The similarity of the oil seed bank was more or less similar to the above ground flora with maximum Sorenson’s similarity values of 0.633. Generally with appropriate management intervention undergrowth vegetation and soil seed bank status in plantation forest had good species composition and diversity.

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