scholarly journals A new model: Herbaceous species diversity along the environmental gradient in the typical hilly areas of Henan Province

2013 ◽  
Vol 5 (1) ◽  
pp. 6-13
Author(s):  
Bing-Hua Liao
2013 ◽  
Vol 6 (4) ◽  
pp. 536-544 ◽  
Author(s):  
Stephen F. Enloe ◽  
Nancy J. Loewenstein ◽  
David W. Held ◽  
Lori Eckhardt ◽  
Dwight K. Lauer

AbstractCogongrass [Imperata cylindrica (L.) Beauv.] is a warm-season, rhizomatous grass native to southeast Asia that has invaded thousands of hectares in the southeastern United States. Its negative impacts on pine forests have been well documented, and aggressive control is widely recommended. Although repeated herbicide treatments are effective for suppression, integrated strategies of prescribed burning coupled with herbicide treatment and revegetation are lacking in pine systems. In particular, longleaf pine forests, which are typically open, fire-dependent, communities, are highly susceptible to cogongrass, which is a pyrogenic species. To address management goals for cogongrass control and herbaceous restoration in longleaf pine forests better, field studies were conducted in southwestern Alabama from 2010 to 2012. Two longleaf pine forests with near-monotypic stands of cogongrass in the understory were selected for study. Treatments included combinations of winter prescribed fire, spring and fall glyphosate herbicide treatments, and seeding a mix of native, herbaceous species. Data were collected for three growing seasons following study initiation, and included seasonal herbaceous species cover and final cogongrass shoot and rhizome biomass. Species richness and diversity were calculated and analyzed to ascertain treatment effects over the duration of the study. Burning slightly improved cogongrass control with glyphosate, but had no effect on total cover, species richness, or species diversity. Three glyphosate treatments reduced total vegetative cover and nearly eliminated cogongrass cover, shoot, and rhizome biomass. Glyphosate and glyphosate + seeding also increased herbaceous species richness and diversity. However, aboveground productivity in treated plots was significantly lower than productivity in the untreated control, which was almost exclusively cogongrass. These studies indicate that glyphosate and integrated strategies utilizing glyphosate and seeding are very useful for cogongrass management and increasing herbaceous species richness and diversity in longleaf pine.


2019 ◽  
Vol 7 (5) ◽  
pp. 502-518
Author(s):  
Pius Yoram Kavana ◽  
Anthony Z. Sangeda ◽  
Ephraim J. Mtengeti ◽  
Christopher Mahonge ◽  
John Bukombe ◽  
...  

Agro-pastoralism involves the growing of crops and keeping of livestock as a livelihood strategy practiced by communities in rural areas in Africa and is highly dependent on environmental factors including rainfall, soil and vegetation. Agro-pastoral activities, e.g. livestock grazing and land clearing for crop cultivation, impact on environmental condition. This study evaluated the impacts of agro-pastoral activities on herbaceous plant species diversity and abundance in western Serengeti relative to conservation (protected) areas. A vegetation survey was conducted along the grazing gradients of ten 4 km transects from within village lands to protected areas. A total of 123 herbaceous species belonging to 20 families were identified. Higher herbaceous species diversity and richness were found in protected areas than in communal grazing lands. Similarly, the number of perennial herbaceous species was higher in the former than the latter, while occurrence of annuals was higher in the village areas. This observation indicates poor rangeland condition in village communal grazing lands as compared with protected areas. It is obvious that current agro-pastoral activities have contributed to a reduction in herbaceous species diversity in village lands in western Serengeti. However, the array of pasture species, especially desirable perennial species, still present in communal grazing areas, suggests that rejuvenation of these areas is possible. Resting of grazing land is recommended to reverse the trend towards diversity reduction and ensure future availability of feed resources for grazing animals in village lands.


2020 ◽  
Vol 153 (2) ◽  
pp. 208-218 ◽  
Author(s):  
Jaquelina A. Nunes ◽  
Pedro M. Villa ◽  
Andreza V. Neri ◽  
Wesley A. Silva ◽  
Carlos E.G.R. Schaefer

Background and aims – Seasonality exerts strong controlling forces on species diversity in herbaceous species communities, however, this control process remains poorly understood in tropical lithologically different rocky outcrops. We aim to investigate the effect of seasonality and the variability of soil properties on changes in the herbaceous species richness and species composition of two different herbaceous species communities on rocky outcrops in Brazil. We hypothesize that seasonality, determined by variation in precipitation, and soil fertility, determined by variability in nutrient-related soil properties, drives species diversity (i.e., richness and beta diversity) patterns of herbaceous communities at local scale.Methods – To investigate how the variation between dry and wet seasons affects species richness and beta diversity, we studied plots on rocky outcrops of Iron Quadrangle (40 plots, 1 × 1 m) and Carajás (20 plots, 1 × 1 m). Key results – We observed similar richness patterns between seasons, without significant differences between sites, using rarefaction and extrapolation curves. However, we observed significant differences in beta diversity between seasons. Our results indicate that seasonality determines the temporal variation of the herbaceous species composition, but not species richness. Likewise, our tested models indicated that seasonality shape beta diversity in the studied rocky outcrops. Conclusions – The predictable seasonal precipitation is closely related to the community composition on this type of rocky outcrop formation, where there typically is a marked seasonal water deficit pattern, with increased deficit during the dry season. We presume that seasonality is an important driver in determining plant community assembly at local scale on the studied rocky outcrops.


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