scholarly journals Interactions between species richness, herbivory and precipitation affect standing biomass in Mongolian rangelands

2021 ◽  
Author(s):  
Julian Ahlborn ◽  
Karsten Wesche ◽  
Birgit Lang ◽  
Munkhzul Oyunbileg ◽  
Batlai Oyuntsetseg ◽  
...  
Keyword(s):  
Species Richness ◽  
Standing Biomass ◽  
Mongolian Rangelands

The role of grazing exclusion by fence in regulating vegetation characteristics and plant diversity in Mongolian rangelands

2020 ◽  
Author(s):  
Tong Guo
Keyword(s):  
Species Richness ◽  
Plant Diversity ◽  
Vegetation Cover ◽  
Grazing Management ◽  
Grazing Exclusion ◽  
Vegetation Characteristics ◽  
Mongolian Rangelands ◽  
The Impact ◽  
Management Effects ◽  
Grassland Types

<p>Grazing largely affects vegetation dynamic of grassland communities. An intensified grazing will likely lead to grassland degradation. Therefore, to restore degraded grasslands, grazing exclusion by fence might be very helpful. However, the direction and the strength of grazing management effects on vegetation characteristics and plant diversity are currently disputable. In addition, vegetation cover and species richness are often independently examined under different grazing regimes in typical studies. Diversity-cover relationship is not adequately detected in degraded grasslands.</p><p>In this study, I aim at understanding effects of grazing exclusion on vegetation characteristics, plant diversity and their relationship. For this, I performed a fencing experiment in three grassland types, namely meadow (since 2009), mountain steppe (since 2013) and dry steppe (since 2013) in Mongolia. Each of three grasslands was set by two treatments: grazing exclusion and freely grazing. Vegetation characteristics were mirrored by vegetation cover and height. Plant diversity was evaluated by indices of species richness, Shannon-Wiener diversity and Pielou evenness.</p><p>The empirical results show that grazing exclusion by fence generally increases vegetation height regardless of grassland types. On the other hand, the changing direction of vegetation cover caused by grazing exclusion is not consistent in three grasslands. Fencing decreases species richness and Shannon diversity. While Pielou evenness responds slightly to changes in grazing regimes. Greater species richness benefits an increment of vegetation cover independent of grazing treatments and grassland types.</p><p>This study fills the knowledge gap of grazing management effects on vegetation characteristics and plant diversity in Mongolian rangelands. The results clearly demonstrate that grazing exclusion by fence is not an efficient way to restore degraded grasslands. This will also allow to project the impact of changes in land use on ecosystem functioning.</p>

Dominance determines fish community biomass in a temperate seagrass ecosystem

2019 ◽  
Author(s):  
Aaron Matthius Eger ◽  
Rebecca J. Best ◽  
Julia Kathleen Baum
Keyword(s):  
Species Richness ◽  
Ecosystem Function ◽  
Fish Community ◽  
Prey Capture ◽  
Fish Communities ◽  
Functional Trait ◽  
Ecosystem Functions ◽  
Community Biomass ◽  
Ecosystem Valuation ◽  
Species Abundances

Biodiversity and ecosystem function are often correlated, but there are multiple hypotheses about the mechanisms underlying this relationship. Ecosystem functions such as primary or secondary production may be maximized by species richness, evenness in species abundances, or the presence or dominance of species with certain traits. Here, we combined surveys of natural fish communities (conducted in July and August, 2016) with morphological trait data to examine relationships between diversity and ecosystem function (quantified as fish community biomass) across 14 subtidal eelgrass meadows in the Northeast Pacific (54° N 130° W). We employed both taxonomic and functional trait measures of diversity to investigate if ecosystem function is driven by species diversity (complementarity hypothesis) or by the presence or dominance of species with particular trait values (selection or dominance hypotheses). After controlling for environmental variation, we found that fish community biomass is maximized when taxonomic richness and functional evenness is low, and in communities dominated by species with particular trait values – those associated with benthic habitats and prey capture. While previous work on fish communities has found that species richness is positively correlated with ecosystem function, our results instead highlight the capacity for regionally prevalent and locally dominant species to drive ecosystem function in moderately diverse communities. We discuss these alternate links between community composition and ecosystem function and consider their divergent implications for ecosystem valuation and conservation prioritization.

Functional evenness of bird communities varies along the elevational gradient in Europe: Conservation implications

2019 ◽  
Author(s):  
Federico Morelli ◽  
Yanina
Keyword(s):  
Species Richness ◽  
Elevation Gradient ◽  
Bird Species ◽  
Elevational Gradient ◽  
Negative Association ◽  
Bird Communities ◽  
Breeding Bird ◽  
Bird Species Richness ◽  
Large Spatial Scale ◽  
Functional Evenness

ContextThe negative association between elevation and species richness is a well-recognized pattern in macro-ecology. ObjectivesThe aim of this study was to investigate changes in functional evenness of breeding bird communities along an elevation gradient in Europe. MethodsUsing the bird data from the EBCC Atlas of European Breeding Birds we estimated an index of functional evenness which can be assumed as a measure of the potential resilience of communities.ResultsOur findings confirm the existence of a negative association between elevation and bird species richness in all European eco regions. However, we also explored a novel aspect of this relationship, important for conservation: Our findings provide evidence at large spatial scale of a negative association between the functional evenness (potential community resilience) and elevation, independent of the eco region. We also found that the Natura2000 protected areas covers the territory most in need of protection, those characterized by bird communities with low potential resilience, in hilly and mountainous areas.ConclusionsThese results draw attention to European areas occupied by bird communities characterized by a potential lower capacity to respond to strong ecological changes, and, therefore, potentially more exposed to risks for conservation.

Plant diversity and species richness of Ljubljana marsh grasslands under the influence of different cutting and fertilizing regimes

2009 ◽  
Vol 57 (2) ◽  
pp. 197-203 ◽  
Author(s):  
T. Sinkovč
Keyword(s):  
Species Richness ◽  
Plant Diversity ◽  
Grassland Management ◽  
Botanical Composition ◽  
Significant Negative Effect ◽  
Negative Effect ◽  
Cutting Regimes ◽  
N Rates ◽  
Exploitation Intensity ◽  
Plot Design

The botanical composition of grasslands determines the agronomic and natural values of swards. Good grassland management usually improves herbage value, but on the other hand it frequently decreases the plant diversity and species richness in the swards. In 1999 a field trial in a split-plot design with four replicates was therefore established on the Arrhenatherion type of vegetation in Ljubljana marsh meadows in order to investigate this relationship. Cutting regimes (2 cuts — with normal and delayed first cut, 3 cuts and 4 cuts per year) were allocated to the main plots and fertiliser treatments (zero fertiliser — control, PK and NPK with 2 or 3 N rates) were allocated to the sub-plots. The results at the 1 st cutting in the 5 th trial year were as follows: Fertilising either with PK or NPK had no significant negative effect on plant diversity in any of the cutting regimes. In most treatments the plant number even increased slightly compared to the control. On average, 20 species were listed on both unfertilised and fertilised swards. At this low to moderate level of exploitation intensity, the increased number of cuts had no significant negative effect on plant diversity either (19 species at 2 cuts vs. 20 species at 3 or 4 cuts). PK fertilisation increased the proportion of legumes in the herbage in the case of 2 or 3 cuts. The proportion of grasses in the herbage increased in all the fertilisation treatments with an increased numbers of cuts. Fertiliser treatment considerably reduced the proportion of marsh horsetail ( Equisetum palustre ) in the herbage of the meadows. This effect was even more pronounced at higher cut numbers. The proportion of Equisetum palustre in the herbage was the highest in the unfertilised sward with 2 cuts (26.4 %) and the lowest in the NPK-fertilised sward with 4 cuts (1.4%).

Linking fish and crustacean taxonomic composition with seasonal contrasts in the soft-bottom intertidal zone

2020 ◽  
Author(s):  
M. A. Gondal ◽  
S. Iqbal ◽  
U. Atique ◽  
N. U. Saher ◽  
N. A. Qureshi ◽  
...  
Keyword(s):  
Species Richness ◽  
Water Temperature ◽  
Fish Species ◽  
Diversity Index ◽  
Taxonomic Composition ◽  
Primary Objective ◽  
Negative Effect ◽  
Fish Species Composition ◽  
One Year ◽  
Sw Monsoon

Abstract The primary objective of this study was to investigate the seasonal fish and crustacean variations concerning taxonomic composition, species richness, and diversity in sandy beach habitat. For this purpose, we investigated the Sonmiani Hor lagoon area during four distinct seasons, i.e., northeast (NE) monsoon, pre-monsoon, south-west (SW) monsoon, and post-monsoon for one year. During each haul, the net was pulled about 100m along the beach in 0.5m depth. The results showed a strong linear correlation between the diversity index and equitability in fishes (r = 0.978). The diversity index was strong negatively correlated with the abundance and biomass (r = -0.978, -0.972, respectively). The physical attributes like sea surface water temperature and salinity showed a strong negative effect on species assemblages (r = -0.981 and -0.943, respectively). The mean air and water temperature illustrated approximately 3°C difference during NE and pre-monsoon seasons. However, salinity, pH, and electrical conductivity did not show any significant seasonal variabilities. Under the ecological indices, the fish species displayed higher diversity (H’ = 3.19) during SW monsoon, whereas the lowest diversity was observed during pre-monsoon (H’ = 1.58). The equitability and species richness, however, remained more noticeable during SW monsoon (J’ = 0.81). The total number of individuals of fish and crustaceans reached 4799 with 3813 fish individuals and 986 individuals of crustaceans. A total of 27 families of fish while five crustacean families comprising of 30 genera and 38 fish species while ten genera and 17 species of crustaceans were recorded. Liza subviridis displayed the highest abundance among the sampled fish species. In conclusion, fish species constituted a significant part of the coastal fauna in the study area. The seasonal variations displayed distinct variations in fish species composition and diversity.

Sign in / Sign up

Export Citation Format

Share Document