scholarly journals Plant community response to fuel break and goat grazing in southern California

2021 ◽  
Author(s):  
Ashley Grupenhoff ◽  
Nicole Molinari
Keyword(s):  
Southern California ◽  
Structural Changes ◽  
Fire Risk ◽  
Woody Species ◽  
Community Response ◽  
Woody Vegetation ◽  
Fuel Management ◽  
Bromus Diandrus ◽  
Goat Grazing ◽  
Initial Fuel

Abstract Background: California is a global biodiversity hotspot, yet increased urbanization of wildlands, warming temperatures, and invasion of nonnative species pose serious risks to these areas due to an increase in wildfire frequency. Fuel management is a tool for reducing fire risk to neighboring communities and natural resources that involves a two-step process requiring an initial reduction of woody vegetation followed by a repeated control of woody plants and reduction of herbaceous cover. To understand the compositional and structural changes resulting from fuel treatment methods in southern California chaparral, we evaluated the compositional and structural impacts of a recently created fuel break established around the Lake Morena community on the Cleveland National Forest. The area was initially treated with cut and pile burning, then treated with herbicide, and lastly grazed by 1,200 goats. The purpose of this study is to (1) evaluate the compositional and structural differences associated with the initial fuel break, and (2) quantify compositional shifts in herbaceous and woody vegetation caused by goat grazing over time. Results: Plots on fuel breaks and in adjacent wildlands exhibited significantly different species assemblages. Total herbaceous cover (both native and nonnative) was 92 times greater on fuel breaks than in adjacent chaparral-dominated wildlands and native shrub cover was 55.3 times greater in adjacent wildlands than on fuel breaks. Goats had a significant impact on reducing native and nonnative herb cover (87% reduction in cover, 92% reduction in height), but were ineffective at reducing the cover and height of most woody species such as Adenostoma fasciculatum, Eriogonum fasciculatum, Quercus berberidifolia, and Artemisia tridentata. However, goats were found to be effective in controlling nonnative grasses including Bromus diandrus and Bromus madritensis. Conclusion: Initial fuel break creation was effective at reducing wood biomass and height, simultaneously giving rise to an abundance and diversity of native and nonnative herbaceous species. Although targeted goat grazing was successful at reducing herbaceous biomass, it was ineffective at reducing woody biomass which is often one of the most important goals for fuel management in chaparral ecosystems.

scholarly journals Plant community response to fuel break construction and goat grazing in a southern California shrubland

Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Ashley Grupenhoff ◽  
Nicole Molinari
Keyword(s):  
Southern California ◽  
Vegetation Change ◽  
Fire Risk ◽  
Woody Species ◽  
Woody Biomass ◽  
Primary Objective ◽  
Community Response ◽  
Management Technique ◽  
Fuel Management ◽  
Goat Grazing

Abstract Background Shrub-dominated ecosystems in California are widespread and provide invaluable ecosystem services to surrounding human-dominated communities. Yet shrublands, especially those at the wildland-urban interface, are at risk of degradation due to increasing wildfire frequency. Strategically placed fuel breaks are an important fuel management technique for reducing fire risk to neighboring communities and natural landscapes. Fuel breaks in shrub-dominated ecosystems are typically linear features where woody biomass is reduced, thereby providing fire suppression opportunities that limit fire spread. While fuel breaks are important for tactical response to fire, they can also affect the composition and structure of shrubland habitats. To understand the ecological changes resulting from fuel treatments in southern California chaparral, we measured vegetation change associated with fuel management techniques on a recently created fuel break established around the Lake Morena community on the Cleveland National Forest. The area was initially treated with cut and pile burning, then treated with herbicide, and 2 years later was subjected to short-term grazing by 1200 goats. The purpose of this study is to (1) evaluate the compositional and structural differences associated with fuel break creation and (2) quantify compositional shifts in herbaceous and woody vegetation caused by short-duration goat grazing as a method of fuel break maintenance. Results Plots on the fuel break and in untreated adjacent chaparral exhibited significantly different species assemblages. Total herbaceous cover (both native and non-native) was 92 times greater on the fuel break than in adjacent chaparral-dominated wildlands, and native shrub cover was 55.3 times greater in untreated adjacent chaparral than on the fuel break. Goats had a significant impact on reducing native and non-native herbaceous cover (87% reduction in cover, 92% reduction in height), but were ineffective at reducing the cover and height of most woody species such as Adenostoma fasciculatum, Eriogonum fasciculatum, Quercus berberidifolia, and Artemisia tridentata. Conclusion Initial fuel break creation was effective at reducing native woody cover and height, simultaneously giving rise to an abundance and diversity of native and non-native herbaceous species. Targeted goat grazing was successful at reducing herbaceous biomass but was ineffective at reducing woody biomass which is often one of the most important goals for fuel management in chaparral ecosystems. In areas where control of woody biomass is the primary objective, land managers should consider grazing duration and plant species composition when contemplating goats as a tool for fuel break maintenance.

scholarly journals Long term effects of fire frequency and season on the woody vegetation dynamics of the Sclerocarya birrea/Acacia nigrescens savanna of the Kruger National Park

Koedoe ◽  
2000 ◽  
Vol 43 (1) ◽  
Author(s):  
B.W. Enslin ◽  
A.L.F. Potgieter ◽  
H.C. Biggs ◽  
R. Biggs
Keyword(s):  
National Park ◽  
Structural Changes ◽  
Environmental Parameters ◽  
Woody Species ◽  
Fire Frequency ◽  
Kruger National Park ◽  
Woody Vegetation ◽  
Long Term Effects ◽  
Season Of Burn

A lack of knowledge together with vacillating fire management approaches in the Kruger National Park until the mid 1950s, gave rise to a long term fire research experiment aimed at shedding light on savanna responses to various combinations of fire fre- quencies and seasons. This trial was laid out in 1954 in four of the six major vegetation zones of the park. With the future of the experiment now being reconsidered, full scale vegetation surveys have been conducted on all the plots and compared to the surveys done in 1954. This paper examines the woody vegetation responses to fourteen fire treatments in the Knobthorn/Marula savanna. Parameters of interest were woody species composition responses, together with tree & shrub density and structural changes. The results indicate that no significant changes in woody species had occurred for the peri- od 1954 vs 1998, while density decreased on biennial and increased on triennial treatments. The proportion of single stemmed plants increased over the period. Season of burn has a marked effect on structure, with April and August burns giving rise to the largest basal areas but the lowest heights. Environmental parameters such as climate, varying herbivory and differing soils, and their respective interactions on vegetation morphology, together with fire behaviour, further influenced results.

scholarly journals The influence of the 1991/92 drought on the woody vegetation of the Kruger National Park

Koedoe ◽  
1995 ◽  
Vol 38 (2) ◽  
Author(s):  
A.J. Viljoen
Keyword(s):  
National Park ◽  
Woody Species ◽  
Aerial Photographs ◽  
Woody Vegetation ◽  
General Area ◽  
Variable Intensity ◽  
The North ◽  
Olifants River ◽  
Area North ◽  
The Impact

All observations and data related to the impact of the 1991/92 drought on the woody vegetation, excluding the riverine vegetation of major rivers, are summarised. This includes data from a visual estimate of damage from aerial photographs, surveys on selected sites, and general observations. Despite lower rainfall, the area north of the Olifants River (excluding the far-northern part) was less affected than the area south of it, suggesting that the woody vegetation in the north is more adapted to drought. A characteristic of the drought was the localised distribution pattern and variable intensity of damage to the same species in the same general area. Information on 31 species are presented briefly. Although a large number of woody species was to some extent damaged, when the woody vegetation is considered as a whole, the influence of the drought was not very severe.

scholarly journals An Assessment of Multiple Drivers Determining Woody Species Composition and Structure: A Case Study from the Kalahari, Botswana

Land ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 122 ◽  
Author(s):  
Meyer ◽  
Holloway ◽  
Christiansen ◽  
Miller ◽  
D’Odorico ◽  
...  
Keyword(s):  
Species Abundance ◽  
Woody Species ◽  
Environmental Variable ◽  
Woody Vegetation ◽  
Tobit Regression ◽  
Species Identity ◽  
Rainfall Gradient ◽  
Composition And Structure ◽  
Species Richness And Abundance ◽  
The Impact

Savannas are extremely important socio-economic landscapes, with pastoralist societies relying on these ecosystems to sustain their livelihoods and economy. Globally, there is an increase of woody vegetation in these ecosystems, degrading the potential of these multi-functional landscapes to sustain societies and wildlife. Several mechanisms have been invoked to explain the processes responsible for woody vegetation composition; however, these are often investigated separately at scales not best suited to land-managers, thereby impeding the evaluation of their relative importance. We ran six transects at 15 sites along the Kalahari transect, collecting data on species identity, diversity, and abundance. We used Poisson and Tobit regression models to investigate the relationship among woody vegetation, precipitation, grazing, borehole density, and fire. We identified 44 species across 78 transects, with the highest species richness and abundance occurring at Kuke (middle of the rainfall gradient). Precipitation was the most important environmental variable across all species and various morphological groups, while increased borehole density and livestock resulted in lower bipinnate species abundance, contradicting the consensus that these managed features increase the presence of such species. Rotating cattle between boreholes subsequently reduces the impact of trampling and grazing on the soil and maintains and/or reduces woody vegetation abundance.

Rangeland vegetation responses to traditional enclosure management in eastern Ethiopia

2013 ◽  
Vol 35 (1) ◽  
pp. 29 ◽  
Author(s):  
H. Haftay ◽  
T. Yayneshet ◽  
G. Animut ◽  
A. C. Treydte
Keyword(s):  
Open Access ◽  
Mass Density ◽  
Canopy Cover ◽  
Woody Species ◽  
Wiener Index ◽  
Woody Vegetation ◽  
Short Term ◽  
Eastern Ethiopia ◽  
Herb Species ◽  
Pastoral Economy

Enclosures are widely used by pastoralists in East Africa. However, the response of herbaceous and woody vegetation to enclosures seasonally grazed by livestock remains poorly understood. This study investigated the effectiveness of traditional enclosures in improving herbaceous and woody vegetation in the Somali Regional State of eastern Ethiopia. Vegetation composition (species composition, diversity and richness) and structure (herbage mass, density and canopy cover) were measured inside and outside a set of enclosures. The enclosures contained higher numbers of desirable species than the adjacent open-access grazing areas. Woody species richness was higher in the open-access grazing areas than in the enclosures, which is attributed to the manual removal of most of the undesirable shrubs and trees in the enclosures by pastoralists. Herbage mass was 2642 and 843 kg of dry matter ha–1 in the enclosures and open-access communal grazing areas, respectively. Herbaceous species diversity was higher in the enclosures than in the open-access communal grazing areas (Shannon–Wiener index: 1.8 v. 1.4, respectively). The enclosures were richer in herb species than the open-access grazing areas (13.5 v. 6.8, respectively), but values for woody species were not significantly different. Overall, we found that establishment of enclosures and the short-term protection from grazing they allow is an option for realising positive vegetation changes that support the local pastoral economy in the semiarid rangelands of eastern Ethiopia.

Structure and Composition of the Abrupt Rain-Forest Boundary in the Herberton Highland, North Queensland

1989 ◽  
Vol 37 (5) ◽  
pp. 413 ◽  
Author(s):  
GL Unwin
Keyword(s):  
Structural Changes ◽  
Woody Species ◽  
Fire Regimes ◽  
Forest Edge ◽  
Permanent Sample Plots ◽  
Boundary Change ◽  
Eucalypt Forest ◽  
Open Forest ◽  
Closed Forest ◽  
Forest Boundary

Structural and floristic features of the rainforest-eucalypt forest boundary are described for two sites on the seasonally clouded eastern slopes of the Herberton Highland, north Queensland. Permanent sample plots, transects and canopy profiles were used to analyse variations across the narrow ecotone. The forest ecotone was found highly variable, spatially and temporally. Within rainforest, richness of woody species was maintained through to the closed forest edge. However, structural changes were more pronounced towards the boundary than were floristic variations and a fringe of immature rainforest varied in depth from 20-500 m. In the open forest margin, tall trees of Eucalyptus grandls were restricted to a narrow zone between the rainforest edge and the broad expanse of medium height Eucalyptus intermedia. Within this transition, young rainforest trees and some shrubs were observed, during a 12-year interval, to be establishing beneath tall E. grandis, displacing fire-prone grasses in the process. The distribution of old E. grandis within rainforest provides a record of recent boundary change. On evidence presented, the rainforest-eucalypt forest boundary is dynamic and parts of the rainforest are expanding due to favourable contemporary fire regimes.

scholarly journals Impacts of Restoration Projects on a Sahelian Woody Vegetation after 21 Years: The Simiri Plateaus (Niger) Case Study

2019 ◽  
pp. 1-12
Author(s):  
Laouali Abdou ◽  
Boubacar Moussa Mamoudou ◽  
Habou Rabiou ◽  
Ali Mahamane ◽  
Josiane Seghieri
Keyword(s):  
Vegetation Cover ◽  
Recovery Rate ◽  
Crop Yields ◽  
Basal Area ◽  
Tree Height ◽  
Woody Species ◽  
Woody Vegetation ◽  
Number Of Stems ◽  
Similar Site

To face the soil and vegetation degradation in Niger, anti-erosion structures, such as scarification of the surface of the ground, half-moons, benches, trenches, stony cordons, were built in 1989 on three Simiri plateaus. Native and introduced woody species were planted and grasses were sown within the structures. This study aims at evaluating what has become the restoration of the woody vegetation cover compared to an un-restored woody cover located on a nearby similar site. Dendrometric parameters and alpha and beta diversities of the four woody stands in 36 sampled plots were analyzed and compared. The following dendrometric values were found significantly lower in the control than in the restored stands: 3.9% against 12.4-16.8% for the recovery rate, 4.3 against 6.3-10.2 cm for the largest stem diameter, 0.2 against 0.8-1.2 m²/ha for the basal area, and 1.6 against 2.0-2.5 m for the tree height. However, the number of stems per trees was found significantly greater in the un-restored stand (6.6) than in the restored ones (1.8-2.7). The values of dendrometric parameters remained low, as well as the alpha and beta diversities whatever the stand. Nevertheless, population perceptions on the restoration impacts that were collected through focus groups indicated positive impacts on downstream crop yields.

scholarly journals Online appendix 1:Exploring an extensive dataset to establish woody vegetation cover and composition in Kruger National Park for the late 1980s

Koedoe ◽  
2014 ◽  
Vol 56 (1) ◽  
Author(s):  
Gregory A. Kiker ◽  
Rheinhardt Scholtz ◽  
Izak P.J. Smit ◽  
Freek J. Venter
Keyword(s):  
Species Richness ◽  
Vegetation Cover ◽  
National Park ◽  
Large Scale ◽  
Plant Cover ◽  
Canopy Cover ◽  
Woody Species ◽  
Kruger National Park ◽  
Tree Cover ◽  
Woody Vegetation

Woody plant cover and species composition play an important role in defining the type and function of savanna ecosystems. Approximately 2000 sites in the Kruger National Park (KNP) were surveyed by F.J. Venter over a period from 1985 to 1989, recording vegetation, soil and topological characteristics. At each of these sites (approximately 20 m × 20 m each), woody vegetation cover and species were recorded using a rapid, Braun-Blanquet classification for three height classes: shrub (0.75 m – 2.50 m), brush (2.50 m – 5.50 m) and tree (> 5.50 m). The objective of this study was to re-analyse the vegetation component of the field data, with a specific focus to provide a spatially explicit, height-differentiated, benchmark dataset in terms of species occurrence, species richness and structural canopy cover. Overall, 145 different woody species were recorded in the dataset out of the 458 species documented to occur in the park. The dataset describes a woody layer dominated by a relatively small number of widely occurring species, as 24 of the most common woody species accounted for all woody species found on over 80% of all sites. The less common woody species (101) were each recorded on 20 sites or less. Species richness varied from 12 to 1 species per site. Structural canopy cover averaged 9.34%, 8.16% and 2.89% for shrub, brush and tree cover, respectively. The dataset provides a useful benchmark for woody species distribution in KNP and can be used to explore woody species and height class distributions, as well as comparison with more recent or future woody vegetation surveys.Conservation implications: The results provided evidence that large-scale, woody vegetation surveys conducted along roads offer useful ecosystem level information. However, such an approach fails to pick up less common species. The data presented here provided a useful snapshot of KNP woody vegetation structure and composition and could provide excellent opportunities for spatio-temporal comparisons.

scholarly journals Woody species of the Miombo woodlands and geoxylic grasslands of the Cusseque area, south-central Angola

Check List ◽  
2017 ◽  
Vol 13 (1) ◽  
pp. 2030 ◽  
Author(s):  
Rasmus Revermann ◽  
Francisco Maiato Gonçalves ◽  
Amândio Luis Gomes ◽  
Manfred Finckh
Keyword(s):  
Species Composition ◽  
Woody Species ◽  
Woody Vegetation ◽  
Growth Forms ◽  
Miombo Woodlands ◽  
Vegetation Survey ◽  
Central Plateau ◽  
South Central ◽  
Independence Era ◽  
Plant Families

The species composition of the vegetation in most regions of Angola has been poorly studied and most studies date back to the pre-independence era. In this study, we provide a detailed account of the woody flora of the Miombo woodlands and geoxylic grasslands of the Cusseque study site of “The Future Okavango” (TFO) project, situated on the Angolan Central Plateau. The checklist is based on a vegetation survey using vegetation plots of 1,000 m² and also includes records from botanical collections made elsewhere at the study site. In total, we documented 154 woody species belonging to 99 genera of 37 plant families in 100 km². The study represents the first comprehensive account of the woody vegetation of the area including all habitats and growth forms.

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