Comparison of vegetation changes along grazing gradients with different numbers of livestock

Hoshino, A.; Yoshihara, Yu; Sasaki, Takehiro; Okayasu, Tomoo; Jamsran, Undarmaa; Okuro, Toshiya; Takeuchi, Kazuhiko

doi:10.1016/j.jaridenv.2009.01.005

Cited by 53 publications

(43 citation statements)

References 20 publications

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“…As such, most preferred plant species cease to grow, giving way for the proliferation of forbs (Chaichi et al 2005;Loydi et al 2012). Similar observations were made by Hoshino et al (2009) who reported that species composition changes along grazing gradients are characterized by changes in density and cover of life forms, and annual species and forbs replace perennial grasses near the piospheres. The results are consistent with Mudongo et al (2016) who observed that continuous grazing led to diminished perennial grass population and increase in forbs and woody species in the Kalahari rangelands of Botswana.…”

Section: Species Compositionsupporting

confidence: 85%

Plant species composition and diversity depending on piospheres and seasonality in the southern rangelands of Kenya

et al. 2017

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Introduction: Scarcity of water in the rangelands of Kenya has led to the introduction of piospheres. Previous research has however produced contrasting results on the effects of piospheres and seasonality on ShannonWiener's diversity index, and therefore, this information is still deficient. In this study, the impact of these piospheres on plant species composition, diversity, and richness was assessed. Methods: Vegetation sampling was done during both the long rains (April) and the dry season (August). Three piosphere types (dam, trough, and a seasonal river) were studied using 0.25 m 2 quadrats to sample vegetation at intervals of 20 m along 100-m transects. Four 100-m transects were used per piosphere (north, east, south, and west directions). Shannon-Wiener's diversity index was used to determine species richness and composition. Twoway ANOVA was used to determine if piospheric distance had an effect on species diversity, richness, and evenness using GenStat 15th edition. Results: A total of 22 grasses and 29 forbs were recorded in the study area. The most abundant grasses near the piospheres were Eragrostis tenuifolia (12.9%) and Cynodon dactylon (10.6%). E. tenuifolia is an increaser species and was therefore most abundant in areas of severe grazing while C. dactylon has been known to be tolerant to grazing. The most abundant forbs were Crotalaria brevidens (37.5%). The Shannon-Wiener diversity index significantly increased (F = 25.07, P = 0.001) with distance from the three piospheres owing to the high grazing intensity near the piospheres and was significantly different between piospheres, being higher (F = 10.05, P = 0.001) at 20 m from the river (1.2 ± 0.1) compared to a similar distance from the dam (0.9 ± 0.1) and the trough (0.8 ± 0.2). This was probably because the trough was smaller in size compared to the other piospheres, thereby concentrating more grazing animals per unit area and causing a greater impact on plant species. Conclusions: The study demonstrated that species diversity, richness, and evenness were low near the piospheres due to heavy grazing. Similarly, the lowest species diversity, richness, and evenness were recorded near the trough compared to the dam and the river. This study therefore recommends that range reseeding and rest period be done to rehabilitate degraded areas and facilitate plant regeneration. Larger piospheres should also be used to minimize animal impact per unit area.

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Section: Species Compositionsupporting

confidence: 85%

Plant species composition and diversity depending on piospheres and seasonality in the southern rangelands of Kenya

et al. 2017

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“…Also, changes in forage species composition with increased presence of unpalatable perennial shrubs beyond the zone of extreme degradation coupled with a decrease in the abundance of palatable native perennial grasses have been documented (James et al 1999). Further, Hoshino et al (2009) showed that vegetation changes along the grazing gradient are characterized with changes in cover of life forms, particularly perennial species being replaced by annual species in close proximity to the piospheres. Further, an ecological niche of vegetation communities with fast growth characteristics that are well adapted to intense and frequent grazing and are also associated with forage of high nutritional quality has been observed to flourish within the sacrifice zone around the water points (Moreno García et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Piospheric influence on forage species composition and abundance in semi-arid Karamoja sub-region, Uganda

et al. 2015

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Piospheres in semi-arid areas are gradients of animal impacts around watering holes. Few studies have examined the impact dynamics of herbaceous and woody species composition and abundance in relation to piospheres in East Africa. In this study, we identified the trend in piosphere development, assessed piosphere use and change indicators, and identified herbaceous and woody plant structure in relation to piospheres in the Karamoja sub-region, Uganda. Results revealed that piosphere development has been reactionary to drought and/or insecurity events and increased rapidly in the last decade. A diversity of herbaceous and woody plants exists around the piospheres. Use and change indicators revealed high trampling and grazing intensity, high presence of erosion signs and low litter cover. Gradient distance had both positive and negative effects on trampling intensity, percent exposure and plant height, respectively. A negative and positive effect of gradient distance was also observed on different herbaceous and woody forage species leading to the identification of both increaser and decreaser species around the piospheres. Therefore, as concentrated use of the piospheres continues unabated, an outward ripple effect leading to loss and/or increase of undesirable herbaceous and woody species will be felt. This will have an impact on the composition and abundance dynamics of desirable forage species in the sub-region.

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“…This has been supported by various studies done in semiarid Southern Africa [5][6][7]. The studies showed that basal cover, proportion of annuals and proportion of unpalatable species were higher in heavily grazed areas than in light grazed areas [5][6][7]. Vegetation outcrops on a disturbed area and surroundings are a function of availability of seeds or propagules of species or species groups.…”

Section: Introductionmentioning

confidence: 69%

“…Heavy grazing pushes the range condition to degraded status dominated by weedy or unpalatable grass and forb species typical of disturbed areas [3,4]. This has been supported by various studies done in semiarid Southern Africa [5][6][7]. The studies showed that basal cover, proportion of annuals and proportion of unpalatable species were higher in heavily grazed areas than in light grazed areas [5][6][7].…”

Section: Introductionmentioning

confidence: 87%

Changes in Herbaceous Species Composition in the Absence of Disturbance in aCenchrus biflorusRoxb. Invaded Area in Central Kalahari Game Reserve, Botswana

Makhabu

Marotsi

2012

International Journal of Ecology

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A-nine year study was carried out to investigate changes in herbaceous species composition in an area invaded by Cenchrus biflorus Roxb, an exotic invader grass species. The study ensued termination of livestock and human activities in the area when residents of the area were relocated to another area. Vegetation characteristics from the disturbed sites (previous occupied areas) and undisturbed sites (previously unoccupied areas) were determined. The results show that C. biflorus has high tolerance to disturbance. It comprised the larger proportion of grasses in disturbed sites at the inception of the study. However, it decreased in abundance with time in disturbed areas and was absent in the undisturbed areas, suggesting that its ability to invade undisturbed sites is limited. Perennial species successfully reestablished on the third year after termination of disturbance. The study reveals that C. biflorus invasion in the Kalahari ecosystem can be controlled by termination of disturbances.

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Comparison of vegetation changes along grazing gradients with different numbers of livestock

Cited by 53 publications

References 20 publications

Plant species composition and diversity depending on piospheres and seasonality in the southern rangelands of Kenya

Plant species composition and diversity depending on piospheres and seasonality in the southern rangelands of Kenya

Piospheric influence on forage species composition and abundance in semi-arid Karamoja sub-region, Uganda

Changes in Herbaceous Species Composition in the Absence of Disturbance in aCenchrus biflorusRoxb. Invaded Area in Central Kalahari Game Reserve, Botswana

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