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.

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 A preliminary report on the dynamics of the vegetation of the Kalahari Gemsbok National Park

Koedoe ◽  
1984 ◽  
Vol 27 (2) ◽  
Author(s):  
N Van Rooyen ◽  
D. J Van Rensburg ◽  
G. K Theron ◽  
J Du P Bothma
Keyword(s):  
Species Composition ◽  
Significant Influence ◽  
Preliminary Report ◽  
National Park ◽  
Floristic Composition ◽  
Woody Species ◽  
Woody Vegetation ◽  
Herbaceous Species ◽  
Short Term ◽  
Basal Cover

Different methods were used intermittently to monitor the changes in the floristic composition, basal cover and density of the herbaceous and woody vegetation over a seven year period in the Kalahari Gemsbok National Park. Periods of drought and the variability of rainfall appear to have a significant influence in the short term on herbaceous species, while there was not much variation in the woody species composition or density.

scholarly journals 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 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.

Development of canopy cover and woody vegetation biomass on reclaimed and unreclaimed post-mining sites

2015 ◽  
Vol 84 ◽  
pp. 233-239 ◽  
Author(s):  
Jan Frouz ◽  
Petr Dvorščík ◽  
Alena Vávrová ◽  
Olga Doušová ◽  
Štěpánka Kadochová ◽  
...  
Keyword(s):  
Canopy Cover ◽  
Woody Vegetation ◽  
Mining Sites ◽  
Vegetation Biomass

scholarly journals Canopy gap colonization in the Atlantic Montane Rain Forest

2006 ◽  
Vol 49 (6) ◽  
pp. 953-965 ◽  
Author(s):  
Renato A. Ferreira de Lima ◽  
Leila Cunha de Moura
Keyword(s):  
Rain Forest ◽  
Woody Species ◽  
Canopy Gap ◽  
Considerable Influence ◽  
Montane Rain Forest ◽  
Eastern Brazil ◽  
Size Number ◽  
Shade Tolerant Species ◽  
Herb Species ◽  
Gap Structure

In the Atlantic Montane Rain Forest of South-eastern Brazil, a study was carried out to describe and evaluate canopy gap colonization. Gap composition by herb species was assessed through their soil coverage and woody species by measuring and identifying all individuals taller than one meter. Gap structure (gap size, number and diameter of treefalls), topographic position and surrounding vegetation were also measured. Two genera of Marantaceae were markedly frequent and abundant inside gaps. The more abundant and frequent woody species were shade tolerant. Species-rich families found inside gaps did not differ from the forest as a whole. Results revealed that direct and indirect influences of topography were important to determine gap composition of woody species. Evidently gap colonization had a considerable influence of topography and pre-established individuals besides variables of gap structure.

scholarly journals Structural, physiognomic and aboveground biomass variation in savanna-forest transition zones on three continents. How different are co-occurring savanna and forest formations?

2014 ◽  
Vol 11 (3) ◽  
pp. 4591-4636 ◽  
Author(s):  
E. M. Veenendaal ◽  
M. Torello-Raventos ◽  
T. R. Feldpausch ◽  
T. F. Domingues ◽  
F. Gerard ◽  
...  
Keyword(s):  
South America ◽  
Woody Plant ◽  
Canopy Cover ◽  
Woody Vegetation ◽  
Canopy Closure ◽  
Forest Transition ◽  
Vegetation Types ◽  
Forest Species ◽  
Stable States ◽  
Transition Zones

Abstract. Through interpretations of remote sensing data and/or theoretical propositions, the idea that forest and savanna represent "alternative stable states" is gaining increasing acceptance. Filling an observational gap, we present detailed stratified floristic and structural analyses for forest and savanna stands mostly located within zones of transition (where both vegetation types occur in close proximity) in Africa, South America and Australia. Woody plant leaf area index variation was related in a similar way to tree canopy cover for both savanna and forest with substantial overlap between the two vegetation types. As total woody plant canopy cover increased, so did the contribution of middle and lower strata of woody vegetation to this total. Herbaceous layer cover also declined as woody cover increased. This pattern of understorey grasses and herbs being progressively replaced by shrubs as canopy closure occurs was found for both savanna and forests and on all continents. Thus, once subordinate woody canopy layers are taken into account, a less marked transition in woody plant cover across the savanna-forest species discontinuum is observed compared to that implied when trees of a basal diameter > 0.1m are considered in isolation. This is especially the case for shrub-dominated savannas and in taller savannas approaching canopy closure. An increased contribution of forest species to the total subordinate cover is also observed as savanna stand canopy closure occurs. Despite similarities in canopy cover characteristics, woody vegetation in Africa and Australia attained greater heights and stored a greater concentration of above ground biomass than in South America. Up to three times as much aboveground biomass is stored in forests compared to savannas under equivalent climatic conditions. Savanna/forest transition zones were also found to typically occur at higher precipitation regimes for South America than for Africa. Nevertheless, coexistence was found to be confined to a well-defined edaphic/climate envelope consistent across all three continents with both soil and climate playing a role as the key determinants of the relative location of forest and savanna. Taken together these observations do not lend support the notion of alternate stable states mediated through fire-feedbacks as the prime force shaping the distribution of the two dominant vegetation types of the tropical lands.

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