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opencc-zeroDec 2017View details →

Data from: Seasonality promotes grassland diversity: interactions with mowing, fertilization and removal of dominant species

1. Current biodiversity declines in species-rich grasslands are connected with the cessation of management, eutrophication and the expansion of dominant grass species. One of the theoretical mechanisms limiting biodiversity loss is the ability of subordinate species to avoid competitive exclusion by seasonal niche separation from dominant species. Here we explore how seasonality underpins the maintenance of diversity in temperate meadows under different management regimes and competition intensities in relation to species functional traits. 2. We studied eight different communities in a long-term meadow experiment that manipulated mowing, fertilization and dominant species (Molinia caerulea) removal. In each community, species-specific trait and biomass data were taken five times during the year to test whether seasonal variation in species composition and functional strategies enable species to coexist. 3. Mown unfertlized meadows exhibited pronounced seasonal variations in community composition and structure, linked to differences in resource-use strategies between mid-summer dominants and the spring and autumn subordinates. Higher specific leaf area and foliar nitrogen concentration in the fast-growing dominants, and increased water use (δ13C) and nutrient acquisition (δ15N) efficiency in resource-retentive subordinates, best predicted their temporal niche separation. Seasonal segregation of species with contrasting strategies increased after mowing cessation, and the resulting summer dominance of Molinia. Conversely, the seasonal dynamics were markedly reduced by fertilization, promoting tall grasses over sedges and forbs throughout the entire year, thereby decreasing the overall taxonomic and functional diversity. When Molinia was removed the compositional changes during the season became less pronounced, being significant only in mown unfertilized plots. 4. Seasonal shifts in community composition reduced the competitive interactions and promoted the coexistence of dominant and subordinate species. Seasonality reversed the negative mid-summer diversity-productivity relationship to a positive one during the spring and autumn, and seasonality only prevented diversity loss in unfertilized conditions possibly because competition is most intense in summer. In fertilized meadows, subordinate species are not able to escape competitive exclusion by shifting their phenological peaks to the spring or autumn periods because asymmetric competition is intense over the entire growing season. Studying seasonal dynamics is key to understanding the maintenance of grassland diversity under ongoing land use change.

opencc-zeroDec 2023View details →

Soil toxicity and species dominance rather than nutrient availability drive plant species richness in swamp forests of Central Europe

Aim: A resource-based conceptual model of plant diversity (RBCM) assumes direct relationships between resource supply and the diversity of a local plant assembly. However, the RBCM largely ignores variation imposed by soil toxicity due to climatic effects. Both soil-limiting resources and soil toxicity vary along climatic gradients but their net and interactive effects on plant species diversity remain unknown. We asked how climatic gradients shape resource availability, soil toxicity and dominance of herb-layer graminoids, and how these predictors control local species diversity of herbs and bryophytes. Location: Swamp forests, Central Europe Taxon: Vascular plants, bryophytes Methods: Alpha taxonomic diversity of vascular plants and bryophytes was counted for 101 vegetation plots sampled in temperate swamp forests distributed along an 800-km geographical gradient across the Continental, Alpine and Pannonian biogeographical regions. Path analysis (structural equation modelling) was used to quantify the direct and indirect effects of climatic variables (potential evapotranspiration; PET), limiting resources (soil N/P, Ca, C/N, proxies for light and water availability), and soil toxicity (Mn) on graminoid dominance and community diversity. Results: PET negatively influenced species richness of both groups analysed either directly or indirectly through its positive effect on the cover of graminoid species. Alpha diversity of herbs was additionally reduced by soil toxicity (Mn). Limiting resources correlated either with species dominance (canopy shading, soil Ca) or with PET (soil N/P ratio), but they did not control species richness pattern. Main Conclusions: Climate, soil toxicity and species dominance determined alpha diversity instead of the expected importance of soil limiting resources. These results are key to advancing the theoretical framework of the RBCM. Increased soil toxicity (Mn) in well-watered regions favours the dominance of plant competitors at the expense of less tolerant species. This implies a potential threat to wetland diversity under ongoing climate change.

opencc-by-4.0Jun 2024View details →

DB3V: A Dialect Dominated Dataset of Bird Vocalisation for Cross-corpus Bird Species Recognition

The first cross-corpus dataset that focuses on dialects in bird vocalisations. The DB3V comprises more than 25 hours of audio recordings from 10 bird species distributed across three distinct regions in the contiguous United States (CONUS).

opencc-zeroJun 2024View details →

Data from: Why are plant communities stable? Disentangling the role of dominance, asynchrony and averaging effect following realistic species loss scenario

A growing number of studies have demonstrated that biodiversity is a strong and positive predictor of ecosystem temporal stability by simultaneously affecting multiple underlying mechanisms of stability i.e. dominance, asynchrony, and averaging effects. However, to date, no study has disentangled the relative role of these key mechanisms of stability in biodiversity experiments. We created a species richness gradient by mimicking a loss of rare species and assessed the role of species richness on community stability and, more importantly, quantified the relative role of three stabilizing mechanisms i.e. dominance (stabilization due to stable dominants compared to the rest of the species in the community), asynchrony (stabilization due to temporal asynchrony between species), and averaging effects (pure effect of diversity) on community stability across a species richness gradient. We found that extreme species loss negatively impacted community stability, but just three species were enough to stabilize biomass production to a level similar to highly diverse communities. However, the similar stability of communities resulted from differing contributions from each stability mechanism, depending on the community diversity. Since less abundant species were more temporally variable, species loss stabilized the populations of the remaining species. The loss of rare and subordinate species reduced the dominance and averaging effects, but increased the asynchrony effect. Hence, the asynchrony effect played a major role in the stability of species poor communities, while the averaging effect drove most of the stability of species rich communities. Overall, dominance played only a minor role, accounting for 5-15% of the stabilization, while asynchrony and averaging effects were dominating forces contributing to ~ 85-95% of the total stabilization. Synthesis. This study highlights the importance of biodiversity and roles of dominant and rare species for long-term community stability and, for the first time, disentangles relative roles of dominance effect, asynchrony, and averaging effect on community stability in a real-world biodiversity experiment.

opencc-zeroJul 2024View details →

Common ant species dominate morphospace: unraveling the morphological diversity in the Brazilian Amazon Basin

Rare plant and vertebrate species have been documented to contribute disproportionately to the total morphological structure of species assemblages. These species often possess morphologically extreme traits and occupy the boundaries of morphological space. As rare species are at greater risk of extinction than more widely distributed species, human-induced disturbances can strongly affect ecosystem functions related to assemblage morphology. Here, we assess to what extent the distributions of ant morphological traits are supported by morphologically extreme species and how they are distributed among habitats in a global biodiversity hotspot, the Brazilian Amazon. We used a morphological database comprising 15 continuous morphological traits and 977 expert-validated ant species distributed across the Brazilian Amazon. We produced species range estimates using species distribution models or alpha hulls (when few records were available). Next, we conducted a principal components analysis to combine traits into a space with reduced dimensionality (morphospace). Then, we identified morphologically extreme species in this space and quantified their contributions to morphological diversity across different habitat types in the Brazilian Amazon Basin. We identified 114 morphologically extreme ant species across the Amazon ant morphospace. These species also accounted for a large percentage of morphospace filling, exceeding 99% representation in the most disturbed habitats in the Amazon. Our results suggest that a few morphologically extreme species capture most of the variation in ant morphology and therefore, the spectrum of ecosystem functions performed by ants in the Brazilian Amazon Basin. Further, unlike for many other groups, these extreme morphologies were represented by the set of most common species. These results suggest greater functional redundancy and resilience in Brazilian Amazon ants, but more broadly, they contribute to our understanding of ecological processes that sustain ecosystem functions.

opencc-by-4.0Jul 2019View details →

Dominance by a single species structures multiple ecological functions in urban landscapes

Dataset used in the analysis of the manuscript "Dominance by a single species structures multiple ecological functions in urban landscapes"

Table 2 in Changes in a soil microarthropod community in the vicinity of dominant tree species under trampling management at the Safari Zoological Center, Israel

Table 2 Mean values (± SD) of soil physical and chemical parameters at different treatment sites at the Safari Zoological Center, Israel, December 2013. SM = soil moisture, OM = organic matter, pH = soil pH, SEC = soil electrical conductivity, SD = soil density, WHC = water-holding capacity. OE = open places under enclosure conditions, OT = open places under trampling conditions; EE E. = camaldulensis canopy habitat under enclosure conditions, ET = E. camaldulensis canopy habitat under trampling conditions, TE T =. aphylla canopy habitat under enclosure conditions, TT = T. aphylla canopy habitat under trampling conditions, CE = C. sempervirens canopy habitat under enclosure conditions, CT = C. sempervirens canopy habitat under trampling conditions. Different letters in the same column represent significant difference p at <0.05.<table><tbody><tr><th></th><th>SM (%)</th><th>OM (%)</th><th>pH</th><th>SEC (µ -1) cm</th><th>SD (g -3) cm</th><th>WHC (%)</th></tr></tbody><tbody><tr><th>OE</th><td>25.6±3.4a</td><td>1.1±0.2b</td><td>7.5±0.2b</td><td>87.6±17.5d</td><td>1.1±0.0b</td><td>53.6±0.9ab</td></tr><tr><th>OT</th><td>7.8±1.7c</td><td>0.2±0.0e</td><td>7.6±0.0b</td><td>150.3±51.3c</td><td>1.6±0.0a</td><td>25.6±1.0c</td></tr><tr><th>EE</th><td>16.6±1.6b</td><td>1.3±0.2b</td><td>7.6±0.0b</td><td>130.2±9.4cd</td><td>1.0±0.1c</td><td>52.6±11.1ab</td></tr><tr><th>ET</th><td>23.2±3.8a</td><td>2.0±0.3a</td><td>7.6±0.0b</td><td>255.3±39.6ab</td><td>1.1±0.0bc</td><td>31.9±3.5c</td></tr><tr><th>TE</th><td>21.9±4.4ab</td><td>0.4±0.1d</td><td>7.9±0.0a</td><td>152.0±17.8c</td><td>1.0±0.1c</td><td>52.1±14.6ab</td></tr><tr><th>TT</th><td>14.1±5.2b</td><td>1.1±0.1b</td><td>7.6±0.1b</td><td>254.1±48.0ab</td><td>1.0±0.1c</td><td>43.3±6.2b</td></tr><tr><th>CE</th><td>26.9±3.4a</td><td>0.8±0.3c</td><td>7.6±0.1b</td><td>209.9±22.5b</td><td>1.0±0.1c</td><td>56.3±5.8a</td></tr><tr><th>CT</th><td>22.0±6.0ab</td><td>0.5±0.2d</td><td>7.8±0.1a</td><td>275.9±21.9a</td><td>1.0±0.0c</td><td>43.0±3.9b</td></tr></tbody></table>

Table 3 in Changes in a soil microarthropod community in the vicinity of dominant tree species under trampling management at the Safari Zoological Center, Israel

Table 3 Effects of sampling habitat (“Habitat”), trampling management (“Trampling”), and their interaction on soil parameters, abundance of soil microarthropods, and diversity indices of soil Acari at the Safari Zoological Center, Israel, December 2013 (General linear model, α = 0.05). * p <0.05, ** p <0.01, *** p <0.001.<table><tbody><tr><th>Microarthropods</th><th>d f</th><th>F</th><th>Soil parameters</th><th>d f</th><th>F</th></tr></tbody><tbody><tr><th>Total microarthropod abundance</th><td></td><td></td><td>Soil moisture</td><td></td><td></td></tr><tr><th>Model</th><td>8</td><td>15.85***</td><td>Model</td><td>8</td><td>109.38***</td></tr><tr><th>Trampling</th><td>1</td><td>39.13***</td><td>Trampling</td><td>1</td><td>18.46***</td></tr><tr><th>Habitat</th><td>3</td><td>1.65</td><td>Habitat</td><td>3</td><td>5.90**</td></tr><tr><th>Trampling * Habitat</th><td>3</td><td>4.89**</td><td>Trampling * Habitat</td><td>3</td><td>12.84***</td></tr><tr><th>Collembola abundance</th><td></td><td></td><td>Organic matter</td><td></td><td></td></tr><tr><th>Model</th><td>8</td><td>4.90**</td><td>Model</td><td>8</td><td>116.32***</td></tr><tr><th>Trampling</th><td>1</td><td>11.18**</td><td>Trampling</td><td>1</td><td>0.05</td></tr><tr><th>Habitat</th><td>3</td><td>2.29</td><td>Habitat</td><td>3</td><td>48.99***</td></tr><tr><th>Trampling * Habitat</th><td>3</td><td>2.56</td><td>Trampling * Habitat</td><td>3</td><td>32.99***</td></tr><tr><th>Other arthropod abundance</th><td></td><td></td><td>Soil pH</td><td></td><td></td></tr><tr><th>Model</th><td>8</td><td>1</td><td>Model</td><td>8</td><td>35120.21***</td></tr><tr><th>Trampling</th><td>1</td><td>1.8</td><td>Trampling</td><td>1</td><td>0.5</td></tr><tr><th>Habitat</th><td>3</td><td>0.73</td><td>Habitat</td><td>3</td><td>4.69*</td></tr><tr><th>Trampling * Habitat</th><td>3</td><td>0.73</td><td>Trampling * Habitat</td><td>3</td><td>13.93***</td></tr><tr><th>Soil Acari abundance</th><td></td><td></td><td>Electrical conductivity</td><td></td><td></td></tr><tr><th>Model</th><td>8</td><td>18.85***</td><td>Model</td><td>8</td><td>156.31***</td></tr><tr><th>Trampling</th><td>1</td><td>43.09***</td><td>Trampling</td><td>1</td><td>61.80***</td></tr><tr><th>Habitat</th><td>3</td><td>0.88</td><td>Habitat</td><td>3</td><td>20.89***</td></tr><tr><th>Trampling * Habitat</th><td>3</td><td>3.60*</td><td>Trampling * Habitat</td><td>3</td><td>1.76</td></tr><tr><th>Taxon richness of soil Acari</th><td></td><td></td><td>Soil density</td><td></td><td></td></tr><tr><th>Model</th><td>8</td><td>16.11***</td><td>Model</td><td>8</td><td>1769.86***</td></tr><tr><th>Trampling</th><td>1</td><td>34.68***</td><td>Trampling</td><td>1</td><td>57.12***</td></tr><tr><th>Habitat</th><td>3</td><td>3.17*</td><td>Habitat</td><td>3</td><td>82.99***</td></tr><tr><th>Trampling * Habitat</th><td>3</td><td>1.23</td><td>Trampling * Habitat</td><td>3</td><td>36.99***</td></tr><tr><th>Shannon index of soil Acari</th><td></td><td></td><td>Water-holding capacity</td><td></td><td></td></tr><tr><th>Model</th><td>8</td><td>18.88***</td><td>Model</td><td>8</td><td>155.49***</td></tr><tr><th>Trampling</th><td>1</td><td>51.07***</td><td>Trampling</td><td>1</td><td>45.98***</td></tr><tr><th>Habitat</th><td>3</td><td>4.03*</td><td>Habitat</td><td>3</td><td>3.22*</td></tr><tr><th>Trampling * Habitat</th><td>3</td><td>0.78</td><td>Trampling * Habitat</td><td>3</td><td>2.6</td></tr><tr><th>Simpson index of soil Acari</th></tr><tr><th>Model</th><td>8</td><td>13.42***</td><td></td><td></td><td></td></tr><tr><th>Trampling</th><td>1</td><td>0</td><td></td><td></td><td></td></tr><tr><th>Habitat</th><td>3</td><td>7.47**</td><td></td><td></td><td></td></tr><tr><th>Trampling * Habitat</th><td>3</td><td>5.22**</td><td></td><td></td><td></td></tr><tr><th>Evenness index of soil Acari</th></tr><tr><th>Model</th><td>8</td><td>42.11***</td><td></td><td></td><td></td></tr><tr><th>Trampling</th><td>1</td><td>120.61***</td><td></td><td></td><td></td></tr><tr><th>Habitat</th><td>3</td><td>3.68*</td><td></td><td></td><td></td></tr><tr><th>Trampling * Habitat</th><td>3</td><td>1.82</td><td></td><td></td><td></td></tr></tbody></table>

Table 1 in Changes in a soil microarthropod community in the vicinity of dominant tree species under trampling management at the Safari Zoological Center, Israel

Table 1 Sampling design (replication = 4) for sites at the Safari Zoological Center, Israel, December 2013. Herbaceous ground cover: +++ patchy; + a few plants, – no plants. OE = open places under enclosure conditions, OT = open places under trampling conditions; EE E =. camaldulensis canopy habitat under enclosure conditions, ET = E. camaldulensis canopy habitat under trampling conditions, TE T =. aphylla canopy habitat under enclosure conditions, TT T =. aphylla canopy habitat under trampling conditions, CE = C. sempervirens canopy habitat under enclosure conditions, CT = C. sempervirens canopy habitat under trampling conditions.<table><tbody><tr><th>Habitat</th><th>Code</th><th>Treatment</th><th>Tree height (m)</th><th>Tree canopy crown (m2)</th><th>Herbaceous vegetation</th><th>Soil physical/biological top layer</th><th>Litter layer (cm)</th></tr></tbody><tbody><tr><th>Open spaces</th><td>OT OE</td><td>Trampling Enclosure</td><td>- -</td><td>- -</td><td>No +++</td><td>No Physical top layer</td><td>No No</td></tr><tr><th>E. camaldulensis</th><td>ET EE</td><td>Trampling Enclosure</td><td>10-13</td><td>6×8</td><td>No +</td><td>No Biological top layer</td><td>No 2-3</td></tr><tr><th>T. aphylla</th><td>TT TE</td><td>Trampling Enclosure</td><td>14-16</td><td>8×8</td><td>No +++</td><td>No Physical top layer</td><td>No Few</td></tr><tr><th>C. sempervirens</th><td>CT CE</td><td>Trampling Enclosure</td><td>14-16</td><td>7×9</td><td>No +</td><td>No Biological layer</td><td>No 1-2</td></tr></tbody></table>

Table 4 in Changes in a soil microarthropod community in the vicinity of dominant tree species under trampling management at the Safari Zoological Center, Israel

Table 4 Correlation coefficients (Pearson correlation, r) between the abundance of microarthropods, diversity indices of soil Acari, and soil parameters at the Safari Zoological Center, Israel, December 2013. SM = soil moisture, OM = organic matter, pH = soil pH, SEC = soil electrical conductivity, SD = soil density, WHC = water-holding capacity p. <*0.05, ** p <0.01, *** p <0.001.<table><tbody><tr><th>Index</th><th></th><th>SM</th><th>OM</th><th>pH</th><th>SEC</th><th>SD</th><th>WHC</th></tr></tbody><tbody><tr><th></th><td>Acari</td><td>0.349*</td><td>0.068</td><td>-0.198</td><td>-0.506**</td><td>-0.299</td><td>0.571***</td></tr><tr><th>Abundance</th><td>Collembola Other soil arthropods</td><td>0.153 0.202</td><td>0.210 0.098</td><td>-0.486** -0.294</td><td>-0.506** -0.209</td><td>-0.107 -0.065</td><td>0.207 0.245</td></tr><tr><th></th><td>Total microarthropod</td><td>0.292</td><td>0.158</td><td>-0.403*</td><td>-0.574***</td><td>-0.233</td><td>0.445*</td></tr><tr><th>Diversity indices of Acari</th><td>Taxon richness Shannon index Simpson index</td><td>0.253 0.285 -0.006</td><td>0.023 0.032 -0.175</td><td>-0.098 -0.120 0.165</td><td>-0.392* -0.455** 0.240</td><td>-0.316 -0.293 -0.475**</td><td>0.561*** 0.585*** 0.336</td></tr><tr><th></th><td>Evenness index</td><td>0.387*</td><td>0.009</td><td>-0.203</td><td>-0.466**</td><td>-0.411*</td><td>0.739***</td></tr></tbody></table>

opencc-zeroAug 2019View details →

Data from: Functional response of subordinate species to intraspecific trait variability within dominant species

1. Dominant species can act as a biotic filter in structuring plant communities by constraining the establishment and survival of subordinate species. The effect of intraspecific trait variability of dominant species on the functional response of subordinate species, however, is not well understood. 2. We quantified intraspecific variation in four functional traits of 26 subordinate species established in an experimental grassland established with two population sources (i.e., cultivars and local ecotypes) of three dominant grasses (Sorghastrum nutans, Andropogon gerardii, and Schizachyrium scoparium) and three pools of subordinate species (each from one origin) within each of the dominant grass source treatments. 3. Twenty of the 26 subordinate species exhibited intraspecific trait variability for one trait or more in response to dominant species population source, and variation among population sources of the dominant species was non-random. Dominant grass population source affected intraspecific variability in functional traits of multiple subordinate species. Cultivar sources of the dominant grasses and some of the subordinate species that established with them had higher and generally more variable functional leaf area and leaf nitrogen content compared to local ecotypes of the dominant grasses and the subordinate species that established with them. 4. Synthesis. This study provides evidence that intraspecific trait variability in dominant species acts as an inner, biotic filter to constrain niche availability and dimensionality affecting trait variation of subordinate species during community assembly.

opencc-zeroJul 2021View details →

Resources do not limit compensatory response of a tallgrass prairie plant community to the loss of a dominant species

The effect of species loss on ecosystem productivity is determined by both the functional contribution of the species lost, and the response of the remaining species in the community. According to the mass-ratio hypothesis, the loss of a dominant plant species, which has a larger proportionate contribution to productivity, is expected to exert an overwhelming effect on this important ecosystem function. However, via competitive release, loss of a dominant species can provide the opportunity for other plant species to establish, thrive and become abundant in the community, potentially compensating for the function lost. Furthermore, if resource limitation is removed, then compensatory response of function to the loss of a dominant species should be greater and more rapid than if resources are more limiting. To evaluate how resources may limit compensation of aboveground productivity to the loss of a dominant plant species, we experimentally removed the C4 perennial tallgrass, Andropogon gerardii, from intact plant communities. We added water for four years, as well as nitrogen in the fourth year, to test the effect of resource limitation on the compensatory response. Overall, aboveground biomass production increased in the remaining community with both water and nitrogen addition. However, this increase in biomass production was not sufficient to fully compensate for the loss of A. gerardii, indicating water and nitrogen were not limiting short-term compensation in this community. Following the removal of the dominant species, there was a reordering of species abundances in the community, rather than changes in species richness. The C4 grass Bouteloua curtipendula was the most responsive species, increasing by 57.9% in abundance with water addition and 91.0% with both water and nitrogen addition. Despite this dramatic increase in abundance, its short stature and lower per capita biomass production prevented this species from compensating for the loss of A. gerardii. Our results suggest that short-term compensation after the loss of a dominant plant species can be hastened by increased resource availability, but ultimately full compensation appears to be limited by the presence and abundance of species in the remaining community that possess traits that allow them compensate for the species lost.

opencc-by-4.0Jul 2021View details →

Dominant plant species in different growth form categories in various ecosystem types

The table contains a list of vegetation parameter values of dominant plant species in different growth form categories in various ecosystem types based on their importance value indices (IVI) (max. IVI for tree and pole category = 300; max. IVI for sapling and seedling category = 200) in Bantimurung Bulusaraung National Park (BBNP) and Hasanuddin University Educational Forest (HUEF), South Sulawesi.

opencc-by-4.0Jul 2021View details →

Dominant plant species in different growth form categories in various ecosystem types

opencc-zeroNov 2022View details →

Contrasting soil- and canopy-nurse effects on dependent species in metalliferous systems may be explained by dominant plant functional strategies

Plant-plant interaction studies in metalliferous systems have focused either on the role of facilitation or on the negative effects of elemental allelopathy. However, no studies have investigated both of these effects in the same system, and their relationships with the functional strategy of the nurse species, although this is crucial for the ecological restoration of polluted sites. We assessed the effects of two dominant nurse species, with apparent contrasting strategies, on two target species on a slag heap in the Pyrenees (France). We quantified both long-term soil-engineering and short-term canopy effects on the growth of two target species. We also measured morphological traits and leaf metal concentration of the two nurse species and their effects on air moisture, temperature, and vapour pressure deficit. Nurse functional strategies, as inferred from morphological traits and leaf metal concentration seem to drive their long-term soil engineering effects on target species: Gypsophila repens, the relatively larger and more exploitative species with high leaf metal concentration, had negative long-term effects likely due to elemental allelopathy, whereas Minuartia verna, the relatively smaller and more conservative species with a lower amount of metals in leaves, had neutral long-term effects. Although Gypsophila repens had a slightly stronger positive effect on microclimate than Minuartia verna, this did not turn into higher short-term effects for the target species. Our study highlights the possible role of the nurse's functional strategies in driving the relative importance of long and short-term effects on target species in metalliferous systems. This knowledge is key to increasing our understanding of plant-plant interaction outcomes in metalliferous systems and our ability to restore polluted environments.

opencc-zeroNov 2022View details →

Community biomass is driven by dominants and their characteristics –the insight from a field biodiversity experiment with realistic species loss scenario

1. Revealing the role of biodiversity in ecosystem functioning (BEF) has been a major focus of ecological research over recent decades. In general, results from artificially assembled communities point to the important role of biodiversity showing that the loss of species has a negative effect on various ecosystem functions (mostly assessed by aboveground peak biomass). However, the evidence from manipulations of natural communities is scarce and results are often contradictory between these two approaches. In particular, the importance of species dominance for ecosystem functioning remains poorly understood. 2. We created a gradient of plant species richness in a meadow community following a realistic species loss scenario (removal of less abundant species) to test the effect of diversity on community biomass and assess the importance of subordinate species compared to dominants in a five-year experiment. 3. Contrasting with the results of BEF experiments with artificial assembly, we did not find any relationship between plant species diversity and aboveground biomass across the timeframe of the experiment. We provide evidence that dominant species' identity and traits are the main drivers of community biomass, because dominant species were able to maintain biomass production after substantial species loss. Further, dominants prevented community biomass from declining and biomass was indirectly influenced not by species richness but through differences in functional diversity. Our results support the mass ratio hypothesis, showing a much bigger effect of dominant species on community biomass production and hints at the rather minor importance of the complementarity effect between species. We emphasize that BEF research should more focus on the role of dominant species in maintaining various ecosystem functions. 4. Synthesis. Species diversity is a poor predictor of community aboveground biomass production and dominant species can effectively compensate the total production after substantial loss of other species in a grassland community.

opencc-zeroDec 2022View details →

Space resource utilization of dominant species integrates abundance- and functional-based processes for better predictions of plant diversity dynamics

Sustainable ecosystem management relies on our ability to predict changes in plant diversity and to understand the underlying mechanisms. Empirical evidence demonstrates that abundance- and functional-based processes simultaneously explain the loss of plant diversity in response to human activities. Recently, a novel indicator based on percent cover (CoverD) and maximum height (HeightD) of the dominant plant species – Space Resource Utilization (SRUD) – has proven to give robust and better predictions of plant diversity dynamics than community biomass. Whether the superior predictive ability of SRUD is due to its capacity to simultaneously capture abundance- and functional-based processes remains unknown. Here, we tested this hypothesis by quantifying mechanistic links between changes in SRUD and biodiversity in response to nutrients and herbivores. Furthermore, we assessed the relative contribution of dominant, intermediate, and rare species to reduced density of individuals by combining null model analysis with field experiments. We found that SRUD successfully captured changes in ground-level light availability and changes in the number of individuals to predict plant diversity dynamics, and each of CoverD and HeightD partly and independently contributed to both processes. Comparative results from null model analysis and field experiments confirmed that individual losses of dominant, intermediate, and rare species followed non-random processes. Specifically, compared with random loss process, rare species lost proportionally more individuals and thus disproportionately contributed to species loss, while dominant and intermediate species lost less. Our results demonstrate that SRUD captures both abundance- and functional-based processes thus explaining why SRUD provides more accurate predictions of changes in species diversity. Given that rare species can play an important role in shaping community structure, resisting against invasion, impacting higher trophic levels, and providing multiple ecosystem functions, reducing the SRU of dominant species could alleviate the risk of exclusion of rare species by mitigating abundance- and functional-based competition processes.

opencc-zeroDec 2022View details →

Data from: Dominant species determine grazing effects on the stability of herbaceous community production at multiple scales in drylands

Sustainable provision of critical ecosystem services in drylands is reliant on their stability under anthropogenic disturbances. Livestock grazing and shrub encroachment are the primary drivers of disturbance that impact their biodiversity and production dynamics. However, the effects of grazing on the stability at multiple scales, particularly following the transition from grass-dominated to shrub-encroached drylands, is still largely unexplored. Here, we conducted comparable sheep-grazing experiments in two types of drylands (grass-dominated vs. shrub-encroached grasslands) on the Mongolia Plateau to explore the effects of grazing and shrub encroachment on biodiversity and stability at multiple scales. We examined how grazing affected the temporal stability of aboveground biomass in herbaceous communities in both grass-dominated and shrub-encroached grasslands, through two potential mechanisms: insurance effects and changes in the population-level stability of individual species. We found that an increase in sheep grazing intensity had significant and negative effects on insurance effects by decreasing both species asynchrony and spatial asynchrony but it had no effects on population stability, consequently leading to reductions in herbaceous community stability of the grasslands. However, grazing-increased insurance effects canceled out grazing-decreased population stability, contributing to no changes in the community stability of shrub-encroached grasslands. Likely, because grazing-induced reductions in the relative abundance of the dominant species were more noticeable in shrub-encroached grasslands than that of in grasslands. Moreover, the grazing-decreased abundance of dominant species was directly correlated to increases in insurance effects in shrub-encroached grasslands but not in grasslands, despite the positive relationships between population stability and the relative abundance of the dominant species in both grass-dominated and shrub-encroached drylands. Synthesis and applications. Our results indicate that grazing can decrease the stability of herbaceous production in drylands, but this negative effect is attenuated with the transition from grasslands to shrub-encroached grasslands, suggesting that grazing effects on herbaceous community stability can be altered by shrub encroachment in drylands. Furthermore, the stability of dominant grasses plays a crucial role in stabilizing herbaceous communities, and should be considered in promoting sustainable ecosystem functioning and services in drylands.

opencc-zeroAug 2023View details →

Functional identity of dominant species in a predator community prevails over functional diversity in shaping the top-down control of herbivores

<ol> <li>Decline in species richness as well as changes in community evenness or functional diversity have been hypothesized to jointly affect ecosystem functioning. However, disentangling the relative effects of these changes in community structure is hard as these different aspects often covary with species richness in real-world ecosystems. In this study, we investigated the individual and interactive effects of functional diversity and community evenness of predators on the level of control of herbivorous prey. </li> <li>Using a highly-replicated mesocosm experiment, we crossed three levels of functional diversity of arthropod predators with two levels of community evenness while controlling for the effect of species richness. Using this experimental setting, we hypothesized that the effect size of functional diversity of predators depends on community evenness. We expected a positive effect of functional diversity of predators on top-down control at a high level of community evenness while we thought that species identity and their associated traits should drive most of the effect on top-down control at a low level of community evenness. </li> <li>Our results did not provide any evidence for an interaction between functional diversity and community evenness nor any beneficial effect of increased functional diversity overall on predation rates of herbivorous prey. In addition, our results revealed that species and functional identity drives most of the effects of predator community composition on top-down control of their prey in our study system. Assemblages composed of active hunters with low handling time and no starvation ability tended to have the highest impacts on prey biomass.</li> <li>By indicating that top-down control of herbivorous prey by arthropod predators is mainly driven by species and functional identity and not by functional diversity, our study provides insights into the consequences of ongoing species loss on ecosystem functioning. Future research should now explore the predictability of trophic interactions based on functional traits of predator and herbivorous prey to anticipate the consequences of changes in species composition on ecosystem functioning.</li> </ol>