What drives plant species diversity? A global distributed test of the unimodal relationship between herbaceous species richness and plant biomass

2014 ◽  
Vol 25 (5) ◽  
pp. 1160-1166 ◽  
Author(s):  
Lauchlan H. Fraser ◽  
Anke Jentsch ◽  
Marcelo Sternberg
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Plant Species ◽  
Plant Biomass ◽  
Plant Species Diversity ◽  
Herbaceous Species ◽  
Distributed Test ◽  
Unimodal Relationship

Regeneration Success and Plant Species Diversity of Allegheny Hardwood Stands After Roundup Application and Shelterwood Cutting

1994 ◽  
Vol 11 (4) ◽  
pp. 109-116 ◽  
Author(s):  
Stephen B. Horsley
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Plant Species ◽  
Negative Impact ◽  
Woody Species ◽  
Diversity Indices ◽  
Species Group ◽  
Plant Species Diversity ◽  
Herbaceous Species ◽  
Species Groups

Abstract The presence of desirable regeneration and plant species diversity was studied in five Allegheny hardwood stands before and for 7 yr after application of Roundup herbicide and shelterwood cutting to remove interfering understories of hayscented and New York fern, striped maple, and beech and to establish desirable hardwood regeneration. In each of five 20 ac stands, 10 ac were sprayed with 1 lb ai (active ingredient)/ac of Roundup in August 1979; the remaining 10 ac were unsprayed. The entire 20 ac stand received a shelterwood seed cut the following winter. On treated plots, fern was reduced from 57% stocking before treatment to 7% 1 yr after treatment; striped maple and beech stocking was reduced by 16% during the same time. By the fourth year after treatment, regeneration stocking of desirable hardwood species had doubled on treated plots but remained unchanged on untreated control plots. Species diversity was measured by species richness, three diversity indices--Berger-Parker, Margalef and Shannon, and index-free diversity ordering. Neither the herbicide treatment nor the shelterwood seed cut had a statistically significant effect on species richness of either woody species or herbaceous species groups. Nor was there a significant effect of treatments on woody species diversity as measured by the three diversity indices. Index-free diversity ordering showed. (1) a trend toward increase in less common species on Roundup-treated areas, and (2) the diversity of herbaceous species groups was higher in all 7 yr after treatment with Roundup. Values of the three diversity indices were higher for herbaceous species on Roundup-treated subplots for 2 to 7 yr after treatment. Much of this increase resulted from germination of seed bank grasses, sedges, and Rubus spp. With the qualification that long-term and current browsing by deer has impoverished the flora of the Allegheny hardwood forest, diminishing potential treatment effects, the study demonstrated that Roundup treatment aided desirable regeneration establishment, did not have a negative impact on woody species or herbaceous species group diversity, and may have increased diversity of herbaceous species. North. J. Appl. For. 11(4): 109-116.

scholarly journals Herbaceous plant species diversity in communal agro-pastoral and conservation areas in western Serengeti, Tanzania

2019 ◽  
Vol 7 (5) ◽  
pp. 502-518
Author(s):  
Pius Yoram Kavana ◽  
Anthony Z. Sangeda ◽  
Ephraim J. Mtengeti ◽  
Christopher Mahonge ◽  
John Bukombe ◽  
...  
Keyword(s):  
Species Diversity ◽  
Protected Areas ◽  
Plant Species ◽  
Rural Areas ◽  
Plant Species Diversity ◽  
Livestock Grazing ◽  
Herbaceous Plant ◽  
Herbaceous Species ◽  
Grazing Land ◽  
Grazing Lands

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.

scholarly journals Herbaceous species diversity patterns across various treatments of herbivory and fire along the sodic zone of the Nkuhlu exclosures, Kruger National Park

Koedoe ◽  
2013 ◽  
Vol 55 (1) ◽  
Author(s):  
Helga Van Coller ◽  
Frances Siebert ◽  
Stefan J. Siebert
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Plant Species ◽  
Significant Variation ◽  
National Park ◽  
Plant Species Richness ◽  
Kruger National Park ◽  
Riparian Zones ◽  
Herbaceous Plant ◽  
Herbaceous Species

Understanding relationships between large herbivores and plant species diversity in dynamic riparian zones is critical to biodiversity conservation. The Nkuhlu exclosures in the Kruger National Park (KNP) provided opportunity to investigate spatial heterogeneity patterns within riparian zones, as well as how these patterns are affected by fire and herbivory. A monitoring project was initiated to answer questions about the dynamics of the herbaceous layer and was aimed at determining, (1) whether there exists meaningful variance in herbaceous plant species richness and diversity across different treatments in the ecologically sensitive sodic zone and (2) whether an increase in herbaceous biomass, an artefact of herbivory and fire exclusion, suppresses herbaceous plant species diversity and richness. Herbaceous vegetation was sampled in two 1 m2 circular sub-plots in the eastern and western corners of 81 fixed plots. The biomass of each plot was estimated with a disc pasture meter (DPM) diagonally with the plot. DPM-readings were converted to kg/ha, according to the latest conversions for the Lowveld Savanna. Species richness and biomass showed significant variance across treatments, whereas no significant variation in herbaceous species diversity was perceived. Combined treatment of fire absence and herbivore presence contributed to higher forb species richness in the sodic zone. Biomass is significantly higher in fully fenced areas where herbivores are excluded, as opposed to the open and partially fenced areas. Although no significant variation was recorded for diversity across treatments, lowest diversity was recorded in the absence of all herbivores, especially in combination with fire treatment. Therefore herbivores are essential in sustaining herbaceous plant species richness in the sodic zone, whilst no significant results were found with regard to their effect on species diversity. Although statistically non-significant, fire seems to suppress species richness.Conservation implications: This study could be used as framework to advance and develop science-based management strategies for, at least, the sodic zones of the KNP. Research in these exclosures will create better understanding of these landscapes, benefit ecosystem conservation planning of national parks and also provide valuable long-term information on key ecological processes.

scholarly journals A six-year grazing exclusion changed plant species diversity of a Stipa breviflora desert steppe community, northern China

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4359 ◽  
Author(s):  
Xing Wang ◽  
Xinguo Yang ◽  
Lei Wang ◽  
Lin Chen ◽  
Naiping Song ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Environmental Factors ◽  
Plant Species ◽  
Northern China ◽  
Plant Species Diversity ◽  
Desert Steppe ◽  
Diversity Patterns ◽  
Shannon Diversity ◽  
Steppe Community

Excluding grazers is one of most efficient ways to restore degraded grasslands in desert-steppe communities, but may negatively affect the recovery of plant species diversity. However, diversity differences between grazed and fenced grasslands in desert-steppe are poorly known. In a Stipa breviflora desert steppe community in Northern China, we established six plots to examine spatial patterns of plant species diversity under grazed and fenced conditions, respectively. We addressed three aspects of species diversity: (1) The logistic, exponential and power models were used to describe the species-area curve (SAR). Species richness, abundance and Shannon diversity values change differently with increasing sampling areas inside and outside of the fence. The best fitted model for SAR was the logistic model. Excluding grazers had a significant impact on the shape of SAR. (2) Variograms was applied to examine the spatial characteristics of plant species diversity. We found strong spatial autocorrelations in the diversity variables both inside and outside the fence. After grazing exclusion, the spatial heterogeneity decreased in species richness, increased in abundance and did not change in Shannon diversity. (3) We used variance partitioning to determine the relative contributions of spatial and environmental factors to plant species diversity patterns. Environmental factors explained the largest proportion of variation in species diversity, while spatial factors contributed little. Our results suggest that grazing enclosures decreased species diversity patterns and the spatial pattern of the S. breviflora desert steppe community was predictable.

Changes in vegetation and soil properties following 6 years of enclosure in riparian corridors

2020 ◽  
Vol 13 (2) ◽  
pp. 131-138
Author(s):  
Di Wang ◽  
Yi-Ran Zhang ◽  
Yu-Long Feng ◽  
Zhi Liu ◽  
Bo Qu
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Species Composition ◽  
Soil Properties ◽  
Plant Species ◽  
Riparian Vegetation ◽  
Vegetation Restoration ◽  
Plant Species Diversity ◽  
Main Stream ◽  
Riparian Corridors

Abstract Aims Riparian corridors play vital roles in the maintenance of biodiversity. Nonetheless, plant species diversity and vegetation coverage in riparian corridors are seriously threatened by increasing pressure owing to livestock consumption and anthropogenic disturbance; even the stability of river courses has been threatened. The establishment of enclosures is a widely used strategy to restore degraded grassland ecosystems, but its impact on degraded herbaceous riparian vegetation and soil properties remains unclear. The aim of this study was to evaluate whether species composition, richness, diversity, and soil properties can be recovered by the enclosure. Methods Twenty long-term monitoring sample plots were set in the Liaohe main stream river, Liaohe main stream river was enclosed for grazing and farmland exclusion in 2012. The height, coverage and individual numbers of plant were recorded for species richness and diversity evaluation from 2012 to 2017; soil nutrients were measured for comparative analysis in 2012 and 2017. We examined the effects of the establishment of enclosures on plant species diversity and soil properties from 2012 to 2017 in the riparian corridors of the Liaohe River system in China. Important Findings Plant species richness and diversity significantly increased from 2012 to 2017. The dominance of Asteraceae plants increased, while the abundance of Gramineae plants decreased over time. The difference in abundance increased each year since enclosure was implemented in 2012. The concentrations of phosphorus and potassium in the soil significantly decreased as a result of the combined effects of vegetation restoration and prohibition of farming practices following the establishment of enclosures. There was also a lag time related to the response of soil organic matter to the establishment of enclosures. In conclusion, our study provides new evidence regarding the response of species diversity, species composition and soil properties following riparian vegetation restoration efforts through enclosure development.

scholarly journals The effect of Agricultural Landscape Type on Field Margin Flora in South Eastern Poland

2016 ◽  
Vol 75 (2) ◽  
pp. 217-225 ◽  
Author(s):  
Małgorzata Wrzesień ◽  
Bożena Denisow
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Plant Species ◽  
Agricultural Landscape ◽  
Vascular Plant ◽  
Detrended Correspondence Analysis ◽  
Agricultural Landscapes ◽  
Plant Species Diversity ◽  
Field Margins ◽  
Landscape Type

Abstract Plant species diversity is threatened in many agricultural landscapes due to the changes it has to undergo. Although the modification of the agricultural landscape pattern is observed across Europe, both extensive and intensive agricultural landscapes still co-exist in Poland. The objective of the study was to examine the flora in field margins in intensively and extensively managed agricultural landscapes, located across three regions in SE Poland. The flora was compared with respect to species richness, diversity, and evenness indices. Detrended correspondence analysis was employed to characterise variation in species composition. Agricultural landscape type made a higher contribution than the topography or geology to species richness and composition in field margins. Field margins function as important habitats for general vascular plant species diversity and are useful for the conservation of rare, threatened, endangered or bee plants. A significant decline in species diversity was observed over a distance of 1000 m from the habitat elements. Plants growing on field margins are mainly perennials; however participation of annuals clearly increases in intensive landscapes. The participation of wind-dispersed species decreased in an open-spaced intensive landscape. Animal-dispersed plants predominated in an extensive landscape with forest islands. Irrespective of landscape type, native species predominated. However, these habitats create the biota and corridors for alien-invasive species as well.

scholarly journals Urbanization increases floral fidelity of pollinators

2021 ◽  
Author(s):  
Sevan Suni ◽  
Erin Hall ◽  
Evangelina Bahu
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Plant Species ◽  
Invasive Plants ◽  
Plant Species Diversity ◽  
Individual Plant ◽  
Native Plant ◽  
Natural Areas ◽  
Short Term ◽  
Urban Sites

Understanding how urbanization alters functional interactions among pollinators and plants is critically important given increasing anthropogenic land use and declines in pollinator populations. Pollinators often exhibit short-term specialization, and visit plants of the same species during one foraging trip. This facilitates plant receipt of conspecific pollen – pollen on a pollinator that is the same species as the plant on which the pollinator was foraging. Conspecific pollen receipt facilitates plant reproductive success and is thus important to plant and pollinator persistence. We investigated how urbanization affects short term specialization of insect pollinators by examining pollen loads on insects’ bodies and identifying the number and species of pollen grains on insects caught in urban habitat fragments and natural areas. We then assessed possible drivers of differences between urban and natural areas, including frequency dependence in foraging, species richness and diversity of the plant and pollinator communities, floral abundance, and the presence of invasive plant species. Pollinators were more specialized in urban fragments than in natural areas, despite no differences in the species richness of plant communities across site types. These differences were likely driven by higher specialization of common pollinators, which were more abundant in urban sites. Pollinators were also more specialized when foraging on invasive plants across sites, and floral abundance of invasive plants was higher in urban sites. Our findings reveal strong effects of urbanization on pollinator fidelity to individual plant species and have implications for the maintenance of plant species diversity in small habitat fragments. The higher fidelity of pollinators to invasive plants suggests that native species may receive fewer visits by pollinators. Therefore, native plant species diversity may decline in urban sites without continued augmentation of urban flora or removal of invasive species.

Predicting plant species diversity in response to disturbance magnitude in grassland remnants of central Alberta

2002 ◽  
Vol 80 (5) ◽  
pp. 504-511 ◽  
Author(s):  
K Vujnovic ◽  
R W Wein ◽  
M R.T Dale
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Exotic Species ◽  
Plant Species ◽  
Intermediate Disturbance Hypothesis ◽  
Plant Species Diversity ◽  
Small Scale ◽  
Intermediate Disturbance ◽  
Total Species Richness ◽  
Disturbance Hypothesis

The Intermediate Disturbance Hypothesis states that the greatest species diversity occurs at intermediate levels of disturbance because species coexistence is maintained at a nonequilibrium state and no strong competitor can dominate completely. On the other hand, diversity of exotic species is expected to increase with the disturbance magnitude. These patterns were tested for in this study. The cover of all vascular plants, mosses, and lichens in 1 × 1 m plots across a range of disturbance levels was sampled in 11 remnant grasslands within the Aspen Parkland Ecoregion of central Alberta, western Canada. The Intermediate Disturbance Hypothesis was supported for small-scale within-patch diversity for total species richness and Simpson's diversity index. Lower species diversity was found in undisturbed and lightly grazed as well as in highly disturbed plots. Intermediate levels of disturbance had reduced dominance of Festuca hallii (Vasey) Piper and increased abundance of most other species; this gave the highest species diversity. The species richness and diversity of exotic plant species showed a significant positive relationship with the magnitude of the disturbance. Understanding relationships between disturbance and plant species diversity, especially exotic plants, can influence management decisions on what disturbance regime is conducive to maintaining natural plant communities.Key words: Intermediate Disturbance Hypothesis, diversity, exotic species, grassland.

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