scholarly journals Effects of grazing season and stocking rate on seed bank in sheep dung on the semiarid Loess Plateau

2019 ◽  
Vol 41 (5) ◽  
pp. 405
Author(s):  
Shulin Wang ◽  
An Hu ◽  
Jing Zhang ◽  
Fujiang Hou
Keyword(s):  
Species Richness ◽  
Loess Plateau ◽  
Seed Bank ◽  
Seed Mass ◽  
Shape Index ◽  
Stocking Rate ◽  
Seedling Density ◽  
Species Richness And Diversity ◽  
Winter Grazing ◽  
Tan Sheep

Endozoochorous dispersal of seeds by livestock has long attracted the attention of grassland scientists, but little is known about seed dispersal via Tan sheep dung on the dry grasslands of the Loess Plateau. We investigated the composition of dung seed bank of Tan sheep under summer and winter rotational grazing regimes at different stocking rates (2.7, 5.3 and 8.7sheepha–1), and assessed the relationships between seed mass and shape, egested seedling density and species richness and diversity. We also assessed the effects of stocking rate and grazing season on seedling density and species richness and diversity of the dung seed bank. Seeds of 10 pasture species germinated from Tan sheep dung with only two being annual species (Eragrostis pilosa and Chenopodium glaucum). The mean seed mass (±s.e.) was 2.59±0.23mg, ranging from 0.10mg (Cleistogenes songorica) to 10.59mg (Thermopsis lanceolata), and the mean seed shape index (±s.e.) was 0.10±0.02, ranging from 0.03 (Lespedeza bicolor) to 0.19 (Stipa bungeana). Species richness and diversity and seedling density decreased with increasing seed mass and shape index, suggesting that small, round seeds are most suitable for endozoochorous dispersal. Stocking rate had no effect on the number of germinated seeds that collected from summer or winter grazing pastures. Species richness and diversity and seedling density were greater in winter grazing pastures than in summer grazing pastures. Jaccard coefficients of similarity between the Tan sheep dung bank and aboveground vegetation were <0.5 for all stocking rates, indicating their weak relationship, but were significantly higher for winter than summer grazing. Plant seeds on the Loess Plateau could disperse through Tan sheep grazing, endozoochory can increase the heterogeneity of rotationally grazed plant communities, and this dispersal mode is an adaptation of plants to the harsh environment of the semiarid areas.

scholarly journals Natural vegetation regeneration from soil seed banks in the cultivated edges of Sudd wetlands in Juba, Southern Sudan

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Josephine Esaete ◽  
Augustine Bongo ◽  
Thomas Lado ◽  
Tomor Bojoi ◽  
Henry Busulwa
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Seed Bank ◽  
Natural Regeneration ◽  
Soil Seed Bank ◽  
Seed Banks ◽  
Interquartile Range ◽  
Seed Density ◽  
Soil Seed Banks ◽  
Species Richness And Diversity

Soil seed banks are important for regeneration of degraded wetlands ecosystems. The Sudd wetlands of Juba city have long been encroached for crop cultivation. Seedling germination was monitored in a greenhouse to establish possible natural regeneration in Mindiari, Rejaf and Roton wetlands in the Sudd. Sixty-four species germinated from the soil seed bank of which 12.5% were dominated by Cyperus difformis and Typha capensis. The findings showed that median wetland species richness in Mindiari was 1.5 (interquartile range = 0.75?3.5), Rejaf 2.5 (interquartile range = 1.0 ? 4.0), Roton 3 (interquartile range = 1.0 ? 5.0) while median Shannon-Wiener diversity was 1.5 (1.14 ?1.73), 1.43 (1.01?1.66), 1.15 (0.98?1.67) for Mindiari, Rejaf and Roton respectively. Both the median seed species richness and diversity were not significantly different among the study wetlands. The median of seed density (56.1) was significantly higher in Roton than in Mindiari (36.7) and Rejaf (29.4) wetlands. The NMDS results showed that species composition of Mindiari and Rejaf was different from Roton. It is concluded that growing crops in wetlands did not influence species richness and diversity but it reduced seed density and altered species composition. Although wetland species were not significantly different in the three-wetland categories, dominance of canopy species belonging to Typhaceae and Cyperaceae indicates that these species are resilient to cultivation and could facilitate natural regeneration of cultivated wetlands edges of the Sudd region in Juba. Further research should examine effect of cultivation duration and flooding regimes on soil seed bank species richness, diversity, and density and composition.

scholarly journals Yak Dung Seed Bank on the Qinghai-Tibetan Plateau: Effects of Grazing Season, Seed Characteristics and Forage Preferences

2021 ◽  
Author(s):  
Shulin Wang ◽  
Fu-Jiang Hou
Keyword(s):  
Tibetan Plateau ◽  
Plant Species ◽  
Seed Bank ◽  
Seed Mass ◽  
Seedling Density ◽  
Seed Shape ◽  
Grazing Season ◽  
Foraging Preferences ◽  
Seed Characteristics ◽  
Yak Dung

Abstract AimsViable seeds in herbivore dung constitute the dung seed bank, and the contribution of livestock dung to this seed bank in grazing pastures is often overlooked. Grazing season (warm and cold), seed characteristics (mass and shape), and forage preference are the main factors that affect the size and composition of the dung seed bank and ultimately affect grassland ecology. However, how these three factors interact is unclear. Methodswe collected yak dung as well as seeds of the common plant species from warm- and cold-season alpine meadows in northeastern Qinghai-Tibetan Plateau, and explored how grazing season (warm and cold), seed characteristics (size and shape) and foraging preferences (temporary cages method) affects yak dung seedling density, richness and diversity in an alpine pasture on the northeastern Qinghai-Tibetan Plateau. ResultsForty-three plant species (mainly perennials) could germinate from yak dung. Dung seedling density, richness, and diversity did not differ significantly between the two grazing seasons. Small-to-medium-sized spherical seeds (seed mass < 10 mg, shape index < 0.5) had the greatest germination potential. ConclusionsYaks vary their forage preference depending on the season (phenological period), and endozoochory occurs throughout both grazing seasons. Seed shape and mass directly regulate the dung seedling density, richness, and diversity. Dung seedlings increase the heterogeneity of the aboveground vegetation near the microsites of the dung pieces and therefore promote grassland patching. Our study demonstrates that grazing season, seed characteristics, and yak forage preferences affect the dung seed bank in grazing ecosystems.

scholarly journals Short-term study on the yak dung seed bank on the Qinghai-Tibetan Plateau: effects of grazing season, seed characteristics and forage preferences

2021 ◽  
Author(s):  
Shulin Wang ◽  
Fujiang Hou
Keyword(s):  
Tibetan Plateau ◽  
Plant Species ◽  
Seed Bank ◽  
Seedling Density ◽  
Seed Shape ◽  
Grazing Season ◽  
Size And Shape ◽  
Foraging Preferences ◽  
Seed Characteristics ◽  
Yak Dung

Abstract Aims Viable seeds in herbivore dung constitute the dung seed bank, and the contribution of livestock dung to this seed bank in grazing pastures is often overlooked. Grazing season (warm and cold), seed characteristics (size and shape), and forage preference are the main factors that affect the size and composition of the dung seed bank and ultimately affect grassland ecology. However, how these three factors interact is unclear. Methods We collected yak dung as well as seeds of the common plant species from warm- and cold-season alpine meadows in northeastern Qinghai-Tibetan Plateau, and explored how grazing season (warm and cold), seed characteristics (size and shape) and foraging preferences (temporary cages method) affects yak dung seedling density, richness and diversity in an alpine pasture. Results Forty-three plant species (mainly perennials) germinated from yak dung. Dung seedling density, richness, and diversity did not differ significantly between the two grazing seasons. Small to medium-sized spherical seeds (seed size < 10 mg, shape index < 0.5) had the greatest germination potential. Conclusions Yaks vary their forage preference depending on the season (phenological period), and endozoochory occurs throughout both grazing seasons. Seed shape and size directly regulate the dung seedling density, richness, and diversity. Dung seedlings increase the heterogeneity of the aboveground vegetation near the microsites of the dung pieces and therefore promote grassland patching. Our study demonstrates that grazing season, seed characteristics, and yak forage preferences affect the dung seed bank in grazing ecosystems.

Field Margin Weed-Species Diversity in Relation to Landscape Attributes and Adjacent Land Use

Weed Science ◽  
2007 ◽  
Vol 55 (2) ◽  
pp. 129-136 ◽  
Author(s):  
Lynn M. Sosnoskie ◽  
Edward C. Luschei ◽  
Mark A. Fanning
Keyword(s):  
Land Use ◽  
Species Richness ◽  
Agricultural Landscape ◽  
Elevation Gradient ◽  
Shape Index ◽  
Diversity Indices ◽  
Weed Species ◽  
Field Margin ◽  
Local Climate ◽  
Modeling Strategy

The importance of managing weeds in seminatural habitats that are adjacent to farm fields is unclear. Weedy-margin vegetation may harbor pests or pathogens and may ALSo serve as source populations for ongoing immigration of weeds into the field. It is ALSo possible, however, that margin vegetation provides habitat for organisms that consume weed seeds or suppress the likelihood of pest or pathogen outbreak. We examined the nature of margin habitat using spatial-scaling of Weed-Species richness as an ecological assay. In 2003, we recorded the occurrence of weedy species along the perimeters of 63 fields in Wisconsin. The fields were distributed within six counties that differed in topography, geological history, local climate, and soil type and which spanned the range of variability in the agricultural landscape. We identified seven habitats that differed in geology and land use. The relationship between species richness and margin class was estimated using an analog of the power law. Additionally, we investigated broadscale correlates of habitat heterogeneity at the field level, using a modeling strategy that included additional explanatory factors logically connected to plant diversity. Using a model-confrontation approach, the survey supported the inclusion of two topographical diversity indices, elevation gradient and a field-shape index, into our model. Our broadscale survey provides information on one of a suite of important considerations needed to make decisions about the importance of managing weeds in field margins.

scholarly journals Species richness and diversity in shrub savanna using ordinary kriging

2016 ◽  
Vol 51 (8) ◽  
pp. 958-966 ◽  
Author(s):  
Anderson Pedro Bernardina Batista ◽  
José Márcio de Mello ◽  
Marcel Régis Raimundo ◽  
Henrique Ferraço Scolforo ◽  
Aliny Aparecida dos Reis ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Species Richness ◽  
Spatial Dependence ◽  
Ordinary Kriging ◽  
Diversity Index ◽  
Spatial Models ◽  
Shannon Diversity Index ◽  
Shannon Diversity ◽  
Species Richness And Diversity ◽  
Number Of Species

Abstract: The objective of this work was to analyze the spatial distribution and the behavior of species richness and diversity in a shrub savanna fragment, in 2003 and 2014, using ordinary kriging, in the state of Minas Gerais, Brazil. In both evaluation years, the measurements were performed in a fragment with 236.85 hectares, in which individual trees were measured and identified across 40 plots (1,000 m2). Species richness was determined by the total number of species in each plot, and diversity by the Shannon diversity index. For the variogram study, spatial models were fitted and selected. Then, ordinary kriging was applied and the spatial distribution of the assessed variables was described. A strong spatial dependence was observed between species richness and diversity by the Shannon diversity index (<25% spatial dependence degree). Areas of low and high species diversity and richness were found in the shrub savanna fragment. Spatial distribution behavior shows relative stability regarding the number of species and the Shannon diversity index in the evaluated years.

Seed banking in ancient forest species: why total sampled area really matters

2012 ◽  
Vol 22 (2) ◽  
pp. 123-133 ◽  
Author(s):  
Jan Plue ◽  
Ken Thompson ◽  
Kris Verheyen ◽  
Martin Hermy
Keyword(s):  
Species Richness ◽  
Seed Bank ◽  
Deciduous Forests ◽  
Forest Species ◽  
Sampling Methodology ◽  
Total Species Richness ◽  
Ancient Forest Species ◽  
Ancient Forest ◽  
Temperate Deciduous ◽  
Temperate Deciduous Forests

AbstractThis study investigates how methodological aspects of seed-bank sampling affect seed-bank records in temperate deciduous forests. We focused explicitly on seed-bank records of ancient forest species, which are assumed to lack a persistent seed bank; a hypothesis suspected to be partly due to methodological shortcomings. Through a quantitative review of 31 seed-bank studies in temperate deciduous forests of central and north-west Europe, we quantified the role of sampling methodology in constraining total seed-bank records and seed-bank records of ancient forest species (γ-diversity, average species' retrieval frequency and average seed density). A major methodological trade-off was established between sampled plot area and the number of plots: at an increased number of plots, the area sampled per plot decreased significantly. The total surface area sampled in a study was the primary determinant of γ-diversity, both for overall species richness and for ancient forest species richness. A high retrieval frequency of ancient forest species indicated that few plots were intensively sampled. The parallel increase in total species richness and ancient forest species richness and the non-significance of their ratio in relation to methodological variables suggests that ancient forest species are not particularly rare in the seed bank compared to other species. These results imply that sampling methodology has a far-reaching impact on seed-bank records such as γ-diversity, the detection of ancient forest species and ultimately seed-bank composition. We formulate a set of guidelines to improve the quality of seed-bank studies in temperate deciduous forests.

scholarly journals Is polychaete diversity in the deep sublittoral of an Antarctic fiord related to habitat complexity?

2012 ◽  
Vol 33 (2) ◽  
pp. 181-197 ◽  
Author(s):  
Krzysztof Pabis ◽  
Jacek Siciński
Keyword(s):  
Species Richness ◽  
Habitat Complexity ◽  
Feeding Guilds ◽  
Depth Range ◽  
Soft Bottom ◽  
Admiralty Bay ◽  
Sea Floor ◽  
Species Richness And Diversity ◽  
South Shetlands ◽  
High Species Richness

Is polychaete diversity in the deep sublittoral of an Antarctic fiord related to habitat complexity?Seventy-six species of Polychaeta were found in 19 quantitative samples collected in the deep sublittoral (200-500 m) of Admiralty Bay (South Shetlands). Three assemblages were distinguished by similarity analysis (clustering, nMDS). The soft bottom in depths from 200 to 300m was strongly dominated byMaldane sarsi antarcticaand had very low species richness and diversity. The second assemblage was distinguished in the areas of the sea floor in the same depth range but with aggregations of Ascidiacea and Bryozoa. It was again characterized by high abundance ofMaldane sarsi antarctica, but showed significantly higher species richness and diversity. Diversity of polychaete feeding guilds was also high in these areas. This pattern was probably associated with an increased habitat complexity due to the presence of dense aggregations of large suspension feeders. High species richness and diversity was also noted in the third assemblage, associated with the deepest sublittoral (400-500 m) of Admiralty Bay. This is the area characterized by very stable environmental conditions, where the assemblage was dominated byTharyx cincinnatus, Sternaspissp.,Maldane sarsi antarctica, andAsychis amphiglypta.

Impacts of Prescribed Fire, Glyphosate, and Seeding on Cogongrass, Species Richness, and Species Diversity in Longleaf Pine

2013 ◽  
Vol 6 (4) ◽  
pp. 536-544 ◽  
Author(s):  
Stephen F. Enloe ◽  
Nancy J. Loewenstein ◽  
David W. Held ◽  
Lori Eckhardt ◽  
Dwight K. Lauer
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Prescribed Fire ◽  
Longleaf Pine ◽  
Pine Forests ◽  
Herbaceous Species ◽  
Integrated Strategies ◽  
Species Richness And Diversity ◽  
Herbicide Treatments ◽  
Rhizome Biomass

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.

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