Species-rich Plant Communities Research Articles

Modern plant fodder resources of the steppes and meadows of the ancient Chir landscape of the “Tsimlyansky” nature reserve

In 2022, studies of the species diversity of plant communities, their aboveground mass and the resource-feeding potential of various types of steppes and meadows in the “Tsimlyansky” nature reserve were conducted. The method of vegetation cover mowing (n = 29) in seven types of steppes and meadows determined the aboveground mass of 101 species of herbaceous plants within the ancient Chir landscape of the Don-Tsimlyansk sand massif. The species richness of plant communities varies between (5.7±1.7) – (14.0±1.2) species/0.25 m2 and averages 10.1±1.0 species/0.25 m2. The average share of cereal species in the communities is 23%, and grasses are almost 3 times more – 64%. The total aboveground biomass in 7 types of steppes and meadows varies between (197.4±25.6) – (379.1±92.5) g/m2. The accumulated mort (necro) mass is (152.2±12.5) – (411.9±43.9) g/m2.

Functional traits shape plant-plant interactions and recruitment in a hotspot of woody plant diversity.

Understanding and predicting recruitment in species-rich plant communities requires identifying functional determinants of both density-independent performance and interactions. In a common-garden field experiment with 25 species of the woody plant genus Protea, we varied the initial spatial and taxonomic arrangement of seedlings and followed their survival and growth during recruitment. Neighbourhood models quantified how six key functional traits affect density-independent performance, interaction effects and responses. Trait-based neighbourhood models accurately predicted individual survival and growth from the initial spatial and functional composition of species-rich experimental communities. Functional variation among species caused substantial variation in density-independent survival and growth that was not correlated with interaction effects and responses. Interactions were spatially restricted but had important, predominantly competitive, effects on recruitment. Traits increasing the acquisition of limiting resources (water for survival and soil P for growth) mediated trade-offs between interaction effects and responses. Moreover, resprouting species had higher survival but reduced growth, likely reinforcing the survival-growth trade-off in adult plants. Resource acquisition of juvenile plants shapes Protea community dynamics with acquisitive species with strong competitive effects suffering more from competition. Together with functional determinants of density-independent performance, this makes recruitment remarkably predictable, which is critical for efficient restoration and near-term ecological forecasts of species-rich communities.

Decreased species richness along bare patch gradient in the degradation of Kobresia pasture on the Tibetan Plateau

The Kobresia pasture in the Tibetan Plateau, as the world's largest and most unique pastoral alpine ecosystem, is undergoing severe degradation, visible in the formation of bare patches. Characteristics of bare patches in Kobresia pastures are regarded as indicators of the fragmentation and degradation of the alpine landscapes. Here, we used unmanned aerial vehicles (UAV)-based low-elevation remote sensing to monitor 72 study sites in the eastern Tibetan Plateau for identifying the spatial patterns of bare patches of Kobresia pasture degradation on regional scale. We conducted field surveys of species composition, quantified fragmentation caused by bare patches using four landscape indices (patch area, total edge length, shape index and splitting index, representing the patch area, length of the edge, shape, and dispersion of the bare patches, respectively), then modeled the response of plant species richness and productivity at the scale of 50 × 50 m to the Kobresia pasture fragmentation process. Our results indicated that species richness and biomass production decreased significantly with each increasing bare patch index. The total edge length of bare patches increased the spatial turnover of plant species. Although bare patch area significantly decreased the species richness of plant communities, it led to a decrease in forb richness and an increase in grass richness along the degradation of Kobresia pastures.Bare patch areas, as the most easily accessible and highly accurate parameter by UAV-based low-elevation remote sensing, significantly related to the decrease in species richness and productivity, and mainly explained the changes in functional group composition. For assessing the ecological integrity of grassland functionality (plant species diversity and above-ground productivity), bare patch area can be used as an important indicator of Kobresia pasture degradation.

Significant decline in habitat specialists in semi-dry grasslands over four decades

Semi-dry grasslands are among the most species-rich plant communities in the world, harbouring many specialised and threatened species. Most of these grasslands were traditionally maintained by grazing and hay-making. After traditional management ended, protected areas were established and conservation management was introduced to protect the most valuable grassland sites. However, recent changes in land use, eutrophication and climate warming are negatively impacting the biodiversity of these grasslands. In 2022, we resurveyed historical vegetation plots in the Central Moravian Carpathians (Czech Republic), first sampled in the 1980s, to test whether the plant species composition and richness of semi-dry grasslands are changing over time and, if so, whether the decline in habitat quality and plant diversity is absent or less severe in protected areas. We found significant changes in species composition. Species richness and the proportion of habitat specialists and Red-List species decreased, whereas competitively stronger species with higher moisture and nutrient requirements increased. These trends were more pronounced outside the protected areas but also occurred within protected areas. The main factor behind these changes appears to be the cessation of traditional management and natural succession supported by eutrophication.

Rare Species Are Significant in Harsh Environments and Unstable Communities: Based on the Changes of Species Richness and Community Stability in Different Sub-Assemblages

To understand the contribution of different sub-assemblages (sub-communities) in the shrub and herb layers to the distribution patterns of community species richness and the stability of the Pinus massoniana Lamb. community, this study was carried out by using 160 shrub quadrats (5 m × 5 m) and 200 herb quadrats (1 m × 1 m). These quadrats were selected from 40 plots on six islands. In this study, common and rare species were classified according to the frequency, and “new communities” (sub-communities) were formed by adding or removing species. Then the changes of species richness and community stability in the “new communities” were analyzed. A redundancy analysis was also used to explore the factors affecting the size of the species richness in the understory of the Pinus massoniana community. The results showed the following: (1) The distribution patterns of both shrub and herb layer species frequencies in this area were plainly to the right, indicating a large proportion of non-common species (common species accounting for 37.87% in the shrub layer and 16.67% in the herb layer). (2) The higher the frequency of species, the greater their contribution to the pattern of species richness. Common species had a high frequency and were the most important contributors to the patterns of species richness in plant communities (64 common species and 41 most common species in the shrub layer and 10 common species in the herb layer each accounted for 95.72, 88.9, and 90.52%, respectively, of the species richness distribution pattern). However, rare species also made significant contributions to the species richness in regions with hard conditions (the (most) rare species in the herb layer explained more than 70% of the species richness distribution pattern, and the remaining species after removing the (most) common species explained more than 90%). (3) In relatively stable communities, rare species had relatively little influence on the stability of the community, which was mostly governed by the dominant species (common species (10 species) were more stable than rare species (38 species), Exc.-rare species (22 species) were more stable than except-common species (50 species), and Exc.-rarest species (35 species) were more stable than Exc.-most common species (55 species) in the herb layer). In less stable communities, the stability of the community gradually increased with the increase in species richness, which may be associated with the growth habit of the increased species (the stability of the herb layer was higher than that of the shrub layer, as shown by the Euclidean distance). The community stability was determined by not only the dominant species in the community but also the rare species that were important contributors to the stability of the communities. (4) The species richness of the shrub layer was considerably influenced (p-value < 0.05) by the soil pH, soil organic matter, and wind speed, whereas the species richness of the herb layer was significantly influenced (p-value < 0.05) by the soil pH. The greater the pH and wind speed, the greater the species richness in the island community. On islands, the soil stability was maintained in large part by the soil organic matter. The lack of soil organic matter can affect soil nutrients, destroy island habitats, and reduce species richness, all of which are harmful to the community stabilization.

Влияние древостоя на фитомассу и видовое разнообразие травяно-кустарничкового яруса в горных лесах Южного Урала

The effect of the stand composition and age of subclimax and secondary forests on the biomass and species diversity of the herb layer in the most common forest type in the western low mountains of the Southern Urals (spruce small-grass-green-moss forests) was investigated. It was found that all of the criteria investigated as species richness of plant community, biomass of herb layer, biodiversity estimated on the basis of Shannon, Pielu, Simpson indices showed high sensitivity to the age and composition of the stand. We found that the graphical models we developed can be used to combine with forest inventory data to obtain large-scale data on biomass and biodiversity of subordinate layers of subclimax and secondary forests in the shallow grass-green-mossy spruce forest type of western low mountains of the Southern Urals.

Flowering phenology of species with similar flower colours in species-rich communities

Within a community, co-occurring plant species are expected to diverge in floral display or flowering phenology to decrease interspecific competition and thus increase intraspecific pollination. However, co-occurring species can also benefit from floral signal standardisation (similar colour signals among flowers of different species) because it facilitates pollinator attraction. Considering the interaction of flower colour display and flowering phenology, we investigated the visual similarity of rewarding flowers among species from highly diverse tropical and temperate vegetation types. For six groups of co-occurring, closely related bee-pollinated species with similar floral displays from Brazilian campo rupestre (51 species) and Spanish Mediterranean vegetation (30 species), we first investigated whether flower colours can be discriminated by bees based on colour locus distance in the bee vision hexagon. We then tested whether flowering phenology overlapped or was segregated. We found that within both vegetation regions, flower colour was generally not distinguishable within groups by bees. The small perceptual distance of colour loci in the bee visual space did not enable discrimination. The flowering periods of the Mediterranean species overlapped, while the Brazilian campo rupestre species tended to have segregated phenologies. Mediterranean species may benefit from the increased standardisation of signals displayed during the short flowering season, while the sequential flowering phenology of campo rupestre species may decrease interspecific competition and help maintain a recognizable signal for bees over time, favouring flower constancy. We concluded that the standardisation of the floral colour signal within these two species-rich plant communities is advantageous for most of the species studied, despite having different flowering phenologies.

Effect of Dominants on the Species Richness of Plant Communities in the Context of the Species–Energy Hypothesis

Effect of Dominants on the Species Richness of Plant Communities in the Context of the Species–Energy Hypothesis

Biotic resistance to fish invasions in southern China: Evidence from biomass, habitat, and fertility limitation.

Understanding the mechanisms underlying the invasion success or failure of alien species can help to predict future invasions and cope with the invaders. The biotic resistance hypothesis posits that diverse communities are more resistant to invasion. While many studies have examined this hypothesis, the majority of them have focused on the relationship between alien and native species richness in plant communities, and results have often been inconsistent. In southern China, many rivers have been invaded by alien fish species, providing an opportunity to test the resistance of native fish communities to alien fish invasions. Using survey data for 60,155 freshwater fish collected from five main rivers of southern China for 3 years, we assessed the relationships between native fish richness and the richness and biomass of alien fishes at river and reach spatial scales, respectively. Based on two manipulative experiments, we further examined the impact of native fish richness on habitat selection and the reproductive ability of an exotic model species Coptodon zillii. We found no apparent relationship between alien and native fish richness, whereas the biomass of alien fish significantly decreased with increasing native fish richness. In experiments, C. zillii preferred to invade those habitats that had low native fish richness, given evenly distributed food resources; reproduction of C. zillii was strongly depressed by a native carnivorous fish Channa maculata. Together, our results indicate that native fish diversity can continue to provide biotic resistance to alien fish species in terms of limiting their growth, habitat selection, and reproduction when these aliens have successfully invaded southern China. We thus advocate for fish biodiversity conservation, especially for key species, to mitigate against the population development and ecological impact of alien fish species.

Soil and Vegetation Cover and Biodiversity Transformation of Postagrogenic Soils of the Volga-Oka Interstream Area

Based on the actual material, the state of the land, previously (more than 15 years ago) placed under cultivation and “neglected” to date, was assessed. Control sites within different landscape provinces of the Volga-Oka interstream area were compared by the state of soil cover and vegetative cover, as well as the type of anthropogenic transformation. The study identified three types of transformation of post-agrogenic lands characteristic of the initial and intermediate overgrowth stages of pre-climax communities: field overgrowth associated with a change in land use; field overgrowth with nearby forest; and field overgrowth without nearby forest. The soil cover state was assessed by acidity, pH, and humus content, and it generally corresponds to the area’s characteristics. Deterioration of these characteristics was noted on sod-podzolic soils overgrown with forest vegetation, as evidenced by low humus content of 0.96–1.46%. The results of research using statistical methods reliably showed that the overgrowth of most sites with herbaceous vegetation within different landscapes followed common successions, even on different soils (sod-podzolic and gray forest). With the leveling of landscape features of areas, there were similar plant species and communities. It was shown that as a result of agricultural overgrowing, the species richness of plant communities was sharply reduced. For example, the maximum value of the Shannon index on overgrown lands is 3.6, which is lower than the reference natural community, where this indicator is 4.1. The remediation of biodiversity in the foreseeable future is very problematic. Although post-agrogenic phytocenoses can gradually restore their productive potential to the level of natural phytocenoses (the maximum value of phytomass in overgrown lands is 10.2 mt/ha, for comparison, natural phytocenoses accumulate 6.3 mt/ha at reference sites), their productivity is provided by a different species composition of herbaceous plants with poor biodiversity. In order to preserve biodiversity, it seems advisable to intersperse croplands with uncultivated plots of sufficiently large size which can serve as a kind of natural ecosystem preservation bank.

Active management fosters species richness of wild bees in limestone quarries

Open and unreclaimed quarries often host species-rich plant and animal communities. However, the specific factors that determine biodiversity in such anthropogenic habitats are largely unknown. This applies in particular to diverse groups of insects. We therefore studied bee assemblages of 16 limestone quarries, eight active and eight abandoned ones, in a Central European landscape with a long history of quarrying. We analysed the influence of macroclimate, landscape quality and habitat quality on overall species richness as well as on the number of threatened and oligolectic species. Our study revealed strong differences in habitat quality and composition of bee assemblages between active and abandoned quarries. Active quarries were larger, had more different pollen sources and a higher cover of early but a lower cover of later successional stages than abandoned quarries. As a result, species richness of bees was higher in active compared to abandoned quarries. Additionally, active quarries were characterized by a unique bee assemblage consisting of several indicator species. Availability of pollen sources and nesting habitats predicted bee species richness in the quarries. Overall, habitat quality and composition of bee assemblages were strongly dependent on quarry management. Active mining continuously created early-successional stages rich in pollen sources and sunlit nesting habitats, favouring species richness of bees in general and of threatened and oligolectic species in particular. Successional speed is generally low in quarries. Nevertheless, in abandoned quarries, later successional stages increasingly dominated due to ongoing succession and, hence, habitat quality and species richness of bees decreased. Considering this, we propose to expand existing quarries rather than build new ones. From a conservation point of view, this approach has several advantages: (i) existing quarries are often already refuges for colonies of rare species; (ii) many species of conservation concern have a low mobility and are therefore unable to occupy remote habitats and (iii) in the impoverished modern-day landscapes, source population that may colonize new quarries are often lacking.

ALIEN AND NATIVE DOMINANTS HAVE A SIMILAR EFFECT ON THE SPECIES RICHNESS OF SYNANTHROPIC PLANT COMMUNITIES OF THE WESTERN CAUCASUS

It remains unclear whether alien dominants, on average, have a stronger effect on the species richness of plant communities than native ones. We examined this issue on the example of 20 areas of synanthropic plant communities dominated by species of different biogeographic origin (the study area is the Western Caucasus, the Belaya River valley, 190-680 m above the sea level). Within each of them, samples of aboveground biomass were taken from 25-30 plots of 0.25 m with different coverings of dominants, which were then sorted by species and weighed. Analysis of the data has shown: 1) the average species richness of samples with a similar degree of dominance of alien and native species differs mainly insignificantly; 2) the close relationship between the degree of dominance of alien species and species richness is, on average, about the same as between the degree of dominance of native species and species richness; 3) the relationship between these characteristics in most cases can be satisfactorily explained on the basis of "energy-diversity" hypothesis; 4) the share of synanthropic plant species in communities with high participation of both alien and aboriginal dominants is not higher than in communities with low participation of these dominants. On the whole, our results indicate a similar and predominantly nonselective nature of the impact of alien and native dominants on accompanying species of communities.

Competitive effects of plant invaders on and their responses to native species assemblages change over time

Alien plant invaders are often considered to be more competitive than natives, and species-rich plant communities are often considered to be more resistant to invaders than species-poor communities. However, the competitive interactions between invaders and assemblages of different species richness are unlikely to be static over time (e.g. during a growth season). To test this, we grew five alien and five native species as invaders in a total of 21 artificial assemblages of one, two or four native competitor species. To test for temporal changes in the reciprocal effects of invaders and the competitor assemblages on each other, and how these depend on the species richness of the assemblages, we harvested plants at three growth stages (weeks 4, 8 and 12). We found that the invaders and competitor assemblages had negative effects on each other. Aboveground biomass of invaders was reduced by the presence of a competitor assemblage, irrespective of its species richness, and this difference gradually increased over time. Alien invaders accumulated more aboveground biomass than the native invaders, but only after 12 weeks of growth. Meanwhile, the invaders also negatively affected the biomass of the competitor assemblages. For multi-species assemblages, the increase in the negative effect of the presence of the invader occurred mainly between weeks 4 and 8, whereas it happened mainly between weeks 8 and 12 for the one-species assemblages. Our results suggest that although alien invaders are more competitive than native invaders, the competitive effects of the invaders on and their responses to native competitor assemblages changed over time, irrespective of the origin of the invaders.

Urbanization increases floral specialization of pollinators.

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 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. In addition, pollinators preferred to forage on invasive plants at urban sites and native plants at natural sites. Our findings reveal indirect effects of urbanization on pollinator fidelity to individual plant species and have implications for the maintenance of plant species diversity in small habitat fragments. Higher preference of pollinators for invasive plants at urban sites 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.

Mapping invasive alien species in grassland ecosystems using airborne imaging spectroscopy and remotely observable vegetation functional traits

Lespedeza cuneata (sericea lespedeza; hereafter “sericea”) is an invasive species brought to the U.S. from East Asia in the 1890s to be used as forage. However, it has now become a growing ecological and economic threat in grasslands of several states in the U.S. southern Great Plains including Oklahoma, Kansas, Missouri, and Nebraska. Here, we demonstrate the capability of airborne imaging spectroscopy to map sericea in a large natural grassland within the Tallgrass Prairie Preserve, the largest protected tallgrass prairie in the world, located in northeastern Oklahoma. Through this research, we investigated which remotely observable vegetation functional traits (referring to biochemical, physiological, and structural traits) contribute to distinguishing sericea from co-occurring native species and whether we can detect sericea remotely through quantifying these functional traits using imaging spectroscopic data (also known as hyperspectral data). To achieve these objectives, full-range airborne hyperspectral data with spatial resolution of 1 m were collected from the study area in August 2020. In addition, a total of 12 vegetation functional traits were measured through field sampling for model development. We first identified functional traits that contributed to separating sericea from other species, and then used them in a classification model to detect sericea in our study site. We found total carotenoids (sum of neoxanthin, violaxanthin, antheraxanthin, zeaxanthin, and lutein), chlorophyll a + b (sum of chlorophyll a and chlorophyll b), total nitrogen, canopy height, potassium, and magnesium as the main functional traits contributing to the detection of sericea; an overall classification accuracy of approximately 94% was reported. However, the proposed approach overestimated sericea cover in species-rich plant communities. Overall, our findings demonstrated an essential role for airborne remote sensing in 1) direct mapping of invasive plants and 2) quantifying functional traits associated with success strategies of invasive species. Eventually, experiments like ours can aid in developing large-scale and science-driven management practices to both identify the current extent, and to control the spread of invasive species in grasslands and similar short-stature environments. This will not only improve management practices but will have major societal and economic benefits.

Small-scale species richness of plant communities with similar biomass: the influence of habitat types in the context of historical hypothesis (Western Caucasus and Ciscaucasia, Black and Azov Seas, Russia)

We compared the species richness of the plant communities of different habitats on different sites of the biomass gradient. The analysis was based on data on 1089 above-ground biomass samples taken from the sites 0.25 m2 of terrestrial herbaceous communities of the Western Caucasus and Ciscaucasia (30–2800 m a.s.l.) and 317 samples taken from the same sites of the macrophytobenthos of the Black and Azov Seas (0.5–10 m depth). Results showed that a certain amount of biomass, sampled in communities of different types, includes, on average, a significantly different number of species. Thus, among terrestrial plant communities, highmountain communities of the Western Caucasus are characterized by the highest species richness in most ranges of the biomass gradient; communities of herb layer of shaded forests – on the contrary, the lowest richness. The macrophytobenthos of the Black Sea is characterized by lower species richness than most of the terrestrial communities, but higher species richness than the benthic communities of the Azov Sea. We showed that significant difference in the small-scale species richness of these communities can be plausibly explained by the peculiarities of their history.

Influence of Selected Environmental Parameters on Rove Beetle (Coleoptera: Staphylinidae) Communities in Central European Floodplain Forests

Wetlands and especially floodplain forests belong to the most endangered ecosystems in Europe, characterized by complex dynamics of flood and dry periods and providing specific irreplaceable habitats for many organisms, including bioindicators. Many rove beetle species, for instance, are well-known detectors in monitoring ecological change, however, their use in environmental assessment requires to expand the insufficient knowledge on ecological environmental particularities of their assemblages. Therefore, we compared the rove beetle communities in eight habitats of floodplain forests from 2015 to 2016. Staphylinids were sampled by pitfall trapping. We compared the rove beetle taxocoenoses in the floodplain forests and their ecotones alongside three rivers (Danube, Tisa and Begej). We evaluated the impact of plant diversity and cover of vegetation layers, area, circumference and age of forest stands, distance to the forest edge, thickness of the litter layer, physical and chemical properties of soil and leaf litter (conductivity, pH, P, N, H, C) and anthropogenic impact on structure of rove beetle communities. We recorded significant interactions between total dynamic activity of rove beetles and number of plant species in shrub vegetation layer. Species richness was significantly positively correlated with number of plant species in shrub vegetation layer and soil pH, and negatively with relative H content of soil. We did not find any significant correlation between Shannon diversity, but evenness was negatively linked with species richness of plant communities in shrub layer.

Emergent spatial patterns of coexistence in species-rich plant communities.

Statistical physics has proved essential to analyze multiagent environments. Motivated by the empirical observation of various nonequilibrium features in Barro Colorado and other ecological systems, we analyze a plant-species abundance model of neutral competition, presenting analytical evidence of scale-invariant plant clusters and nontrivial emergent modular correlations. Such first theoretical confirmation of a scale-invariant region, based on percolation processes, reproduces the key features in natural rainforest ecosystems and can confer the most stable equilibrium for ecosystems with vast biodiversity.

Result of Impact of Dominants on Species Richness of Plant Communities: Ordered or Random Species Loss?

Result of Impact of Dominants on Species Richness of Plant Communities: Ordered or Random Species Loss?

Plant-soil feedbacks help explain biodiversity-productivity relationships

Species-rich plant communities can produce twice as much aboveground biomass as monocultures, but the mechanisms remain unresolved. We tested whether plant-soil feedbacks (PSFs) can help explain these biodiversity-productivity relationships. Using a 16-species, factorial field experiment we found that plants created soils that changed subsequent plant growth by 27% and that this effect increased over time. When incorporated into simulation models, these PSFs improved predictions of plant community growth and explained 14% of overyielding. Here we show quantitative, field-based evidence that diversity maintains productivity by suppressing plant disease. Though this effect alone was modest, it helps constrain the role of factors, such as niche partitioning, that have been difficult to quantify. This improved understanding of biodiversity-productivity relationships has implications for agriculture, biofuel production and conservation.