Plant Species Richness Research Articles

Childcare centre soil microbiomes are influenced by substrate type and surrounding vegetation condition

Urban development has profoundly reduced human exposure to biodiverse environments, which is linked to a rise in human disease. The ‘biodiversity hypothesis’ proposes that contact with diverse microbial communities (microbiota) benefits human health, as exposure to microbial diversity promotes immune training and regulates immune function. Soils and sandpits in urban childcare centres may provide exposure to diverse microbiota that support immunoregulation at a critical developmental stage in a child's life. However, the influence of outdoor substrate (i.e., sand vs. soil) and surrounding vegetation on these environmental microbiota in urban childcare centres remains poorly understood. Here, we used 16S rRNA amplicon sequencing to examine the variation in bacterial communities in sandpits and soils across 22 childcare centres in Adelaide, Australia, plus the impact of plant species richness and habitat condition on these bacterial communities. We show that sandpits had distinct bacterial communities and lower alpha diversity than soils. In addition, we found that plant species richness in the centres' yards and habitat condition surrounding the centres influenced the bacterial communities in soils but not sandpits. These results demonstrate that the diversity and composition of childcare centre sandpit and soil bacterial communities are shaped by substrate type, and that the soils are also shaped by the vegetation within and surrounding the centres. Accordingly, there is potential to modulate the exposure of children to health-associated bacterial communities by managing substrates and vegetation in and around childcare centres.

Sensitivity to agricultural inputs and dispersal limitation determine the response of arable plants to time since transition to organic farming

Abstract Transitioning to low‐input agricultural systems such as organic farming has been acknowledged as a way to mitigate negative effects of agriculture on biodiversity. However, the speed, magnitude and context dependence of biodiversity recovery after converting to organic farming remain uncertain. In this study, we explored the response of plant communities to time since transition to organic farming in a variety of production contexts. Using a spatially replicated space‐for‐time substitution design, we surveyed plant communities in small‐grain cereal and ley fields in conventional and organic farms, distributed along independent gradients of time since transition to organic farming and proportion of seminatural grasslands in the landscapes. We selected a set of response traits to explore the mechanism of potential time lag in that response to conversion. These traits were selected to characterize the sensitivity of plant species to agricultural inputs and their ability to respond swiftly to environmental changes. We found an increase in plant species richness and evenness in cereal fields with increasing time since transition to organic farming, and a similar but less pronounced pattern in leys. After 30 years of continuous organic farming, organic cereal fields harboured more than twice the number of plant species than newly converted fields. Importantly, we found that the dependence on insect pollination, sensitivity to herbicides and dispersal capacity of plants modulated the effects of time since transition on plant communities in cereal fields. This suggests that both management and biotic interactions shape plant community structure in response to organic practices over time. Policy implications. Our study highlights that benefits of organic farming for plant diversity are likely to take decades to become substantial after conversion. We found this slow recovery of plant communities to be driven by both the gradual improvement of habitat quality after conversion and species' dispersal limitation. Assessments of biodiversity benefits of organic farming should therefore consider this time delay to avoid underestimating its environmental performance. Farmers should also be supported during this ecological transitional phase during which yield‐enhancing ecosystem services reliant on plant diversity might build up.

Yak and Tibetan sheep dung increase the proportional biomass of grasses and alleviate soil nitrogen limitation in degraded Tibetan alpine grassland

The dung of Tibetan livestock serves as a natural fertilizer that plays a crucial role in maintaining plant productivity and restoration of degraded alpine grasslands. However, research on how livestock dung affects vegetation composition and soil quality in Tibetan alpine grassland on the time scale remains uncertain. We established three types of nutrients (yak dung, Tibetan sheep dung and urea) and control on a Tibetan alpine grassland in 2017, and measured the vegetation (species composition, aboveground biomass, composition of functional group biomass, and species diversity) and soil characteristics (soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP)), and calculated the SOC/TN, SOC/TP and TN/TP ratios) at the end of August 2017, 2018, and 2019. The study aimed to compare the effect organic fertilizers (two Tibetan livestock dungs) and inorganic nitrogen fertilizer (urea) on vegetation characteristics and soil chemical properties, and to assess whether the livestock dung can improve soil nutrient availability level in degraded Tibetan alpine grassland. Our results showed that: (1) Tibetan sheep dung delayed the increase of aboveground biomass, and urea increased the aboveground biomass in 2017 and 2018; (2) yak and Tibetan sheep dungs and urea increased proportional biomass of aboveground grasses and plant species richness index in the three years; and (3) livestock dungs increased SOC, TN, the ratios of SOC/TP and TN/TP in 2018. Our study implies that yak and Tibetan sheep dung stimulated plant growth and altered soil nutrients, while alleviating soil nitrogen limitation in degraded alpine grasslands. The return of livestock dung to soil may be a sustainable alternative to chemical fertilizers in near-natural recovery of degraded Tibetan alpine grasslands.

Plant growth-defense trade-offs are general across interactions with fungal, insect, and mammalian consumers.

Plants face trade-offs between allocating resources to growth, while also defending against herbivores or pathogens. Species differences along defense trade-off axes may promote coexistence and maintain diversity. However, few studies of plant communities have simultaneously compared defense trade-offs against an array of herbivores and pathogens for which defense investment may differ, and even fewer have been conducted in the complex natural communities in which these interactions unfold. We tested predictions about the role of defense trade-offs with competition and growth in diversity maintenance by tracking plant species abundance in a field experiment that removed individual consumer groups (mammals, arthropods, fungi) and added nutrients. Consistent with a growth-defense trade-off, plant species that increased in mass in response to nutrient addition also increased when consumers were removed. This growth-defense trade-off occurred for all consumer groups studied. Nutrient addition reduced plant species richness, which is consistent with trade-off theory. Removing foliar fungi increased plant diversity via increased species evenness, whereas removal of other consumer groups had little effect on diversity, counter to expectations. Thus, while growth-defense trade-offs are general across consumer groups, this trade-off observed in wild plant communities does not necessarily support plant diversity maintenance.

Nitrogen addition alleviates the adverse effects of drought on plant productivity in a temperate steppe.

Drought and nitrogen enrichment could profoundly affect the productivity of semiarid ecosystems. However, how ecosystem productivity will respond to different drought scenarios, especially with a concurrent increase in nitrogen availability, is still poorly understood. Using data from a 4-year field experiment conducted in a semiarid temperate steppe, we explored the responses of aboveground net primary productivity (ANPP) to different drought scenarios and nitrogen addition, and the underlying mechanisms linking soil properties, plant species richness, functional diversity (community-weighted means of plant traits, functional dispersion) and phylogenetic diversity (net relatedness index) to ANPP. Our results showed that completely excluding precipitation in June (1-month intense drought) and reducing half the precipitation amount from June to August (season-long chronic drought) both significantly reduced ANPP, with the latter having a more negative impact on ANPP. However, reducing half of the precipitation frequency from June to August (precipitation redistribution) had no significant effect on ANPP. Nitrogen addition increased ANPP irrespective of drought scenarios. ANPP was primarily determined by soil moisture and nitrogen availability by regulating the community-weighted means of plant height, rather than other aspects of plant diversity. Our findings suggest that precipitation amount is more important than precipitation redistribution in influencing the productivity of temperate steppe, and nitrogen supply could alleviate the adverse impacts of drought on grassland productivity. Our study advances the mechanistic understanding of how the temperate grassland responds to drought stress, and implies that management strategies to protect tall species in the community would be beneficial for maintaining the productivity and carbon sequestration of grassland ecosystems under climate drought.

Promoting plant diversity and habitat heterogeneity through vineyard terracing

AbstractQuestionsViticulture on steep slopes has shaped the landscape and biodiversity in many regions, but insufficient profitability has led to management cessation and shrub encroachment. A solution to maintain economically viable cultivation could be vineyard terracing. We aimed to identify the potential of terracing to enhance plant diversity and habitat heterogeneity in vineyards, analyze effects of management intensity on vineyard vegetation, and assess how plant communities change after vineyard abandonment.LocationWine‐growing region of the Upper Middle Rhine Valley in Hesse (50.042342° N, 7.814533° E) and Rhineland‐Palatinate (50.119139° N, 7.719275° E), Germany.MethodsWe recorded vascular plant species and local vineyard parameters in vertically oriented vineyards with vegetated and tilled open inter‐rows, in terraced vineyards with tilled terrace inter‐rows and extensively managed embankments, and in vineyard fallows in a total of 45 study sites. We used plant species richness, Ellenberg indicator values and Grime's strategy types to describe how traits and ecological requirements respond to distinct vineyard management.ResultsPlant species richness and composition were determined by management‐derived disturbance intensities. Extensively managed embankments had a distinct plant community, the highest plant species richness, more perennial and indicator species, and lower nitrogen indicator values compared with inter‐rows. By contrast, highly disturbed open and terrace inter‐rows revealed plant communities associated with annuals and ruderals, but species richness did not differ between terrace inter‐rows and embankments. The plant communities of fallows were completely different with lower plant diversity.ConclusionsOur results highlight the potential of terraced vineyards for plant diversity with nutrient poor, extensively managed embankments providing conditions that have become rare in modern agricultural systems. A long environmental gradient from terrace inter‐rows to embankments created habitat heterogeneity within a narrow space. By contrast, intensive inter‐row management in vertically oriented vineyards hampers high plant diversity and abandonment fosters the spread of woody species at the expanse of plant diversity.

Maintaining habitat diversity at small scales benefits wild bees and pollination services in mountain apple orchards

Abstract Landscape context influences wild bee abundance and diversity, alongside pollination‐related services. Growing evidence supports the positive effects of landscape heterogeneity on bee diversity and fruit production for pollination‐dependent crops in flatlands. However, little remains known about these relationships in mountainous environments where the landscape matrix surrounding crops is often more complex than in lowlands. We conducted our study in apple orchards in South Tyrol, an Alpine region in Italy, using pan‐traps, direct observations of visitation frequency and a pollinator exclusion experiment. We investigated the scale‐dependent effects of landscape heterogeneity and other parameters on wild bee assemblages and the related pollination service they provide at five spatial scales (radius 100–2000 m). We found that landscape heterogeneity positively affected the abundance and richness of wild bees, with the strongest effect at 500 m. We calculated a multidiversity index, reflecting the land‐use intensity based on the species richness of vascular plants, grasshoppers, butterflies, birds and bats. We identified a positive relationship between this multidiversity index and wild bee richness. Additionally, we found that visitation rate of wild bees was negatively affected by crop cover and that abundance of honeybees did not influence wild bee visitation rate or reproductive success. Finally, reproductive success was positively related to semi‐natural habitat cover. Landscape heterogeneity should be maintained in apple orchards to continue to reap the benefits of vital pollination‐related services. Diversification strategies should be implemented to promote habitat diversity at small scales, even in regions with more than 80% of (semi‐)natural habitats.

A novel hybrid beachgrass is invading U.S. Pacific Northwest dunes with potential ecosystem consequences

AbstractInvasive plants formed via hybridization, especially those that modify the structure and function of their ecosystems, are of particular concern given the potential for hybrid vigor. In the U.S. Pacific Northwest, two invasive, dune‐building beachgrasses, Ammophila arenaria (European beachgrass) and A. breviligulata (American beachgrass), have hybridized and formed a new beachgrass taxa (Ammophila arenaria × A. breviligulata), but little is known about its distribution, spread, and ecological consequences. Here, we report on surveys of the hybrid beachgrass conducted across a 250‐km range from Moclips, Washington to Pacific City, Oregon, in 2021 and 2022. We detected nearly 300 hybrid individuals, or an average of 8–14 hybrid individuals per km of surveyed foredune. The hybrid was more common at sites within southern Washington and northern Oregon where A. breviligulata is abundant (75%–90% cover) and A. arenaria is sparse and patchy. The hybrid displayed morphological traits such as shoot density and height that typically exceeded its parent species suggesting hybrid vigor. We measured an average growth rate of 30% over one year, with individuals growing faster at the leading edge of the foredune, nearest to the beach. We also found a positive relationship between hybrid abundance and A. arenaria abundance, suggesting that A. arenaria density may be a controlling factor for hybridization rate. The hybrid showed similar sand deposition and associated plant species richness patterns compared with its parent species, although longer term studies are needed. Finally, we found hybrid individuals within and near conservation habitat of two Endangered Species Act‐listed, threatened bird species, the western snowy plover (Charadrius alexandrinus nivosus) and the streaked horned lark (Eremophila alpestris strigata), a concern for conservation management. Documenting this emerging hybrid beachgrass provides insights into how hybridization affects the spread of novel species and the consequences for communities in which they invade.

Prediction of species richness and diversity in sub‐alpine grasslands using satellite remote sensing and random forest machine‐learning algorithm

AbstractAimsRemote‐sensing approaches could be beneficial for monitoring and compiling essential biodiversity data because they are cost‐effective and allow for coverage of large areas over a short period. This study investigated the relationship between multispectral remote‐sensing data from Landsat 8 and Sentinel‐2 and species richness and diversity in mountainous and protected grasslands.LocationsGolden Gate Highlands National Park, Free State, South Africa.MethodsIn‐situ data of plant species composition and cover from 142 plots with 16 relevés each were distributed across the study site and used to calculate species richness and Shannon–Wiener species diversity index (species diversity). We used a machine‐learning random forest algorithm to optimize the prediction of species richness and diversity. The algorithm was used to identify the optimal spectral bands and vegetation indices for estimating species richness and diversity. Subsequently, the selected bands and vegetation indices were used to estimate species richness through random forest regression.ResultsThis research found weak relationships between remote‐sensing vegetation indices and the diversity metrics, but significant relationships were found between some spectral bands and diversity metrics. Moreover, using machine‐learning random forest, the multispectral data sets exhibited strong predictive powers. In this investigation, near‐infrared (NIR) seemed to be the most selected band for both sensors to explain species diversity in mountainous grasslands.Main conclusionsThis finding further ascertains the efficiency of optimizing high spatial resolution spectral information to estimate plant species richness and diversity. This research shows that NIR, Soil‐Adjusted Vegetation Index (SAVI) and Enhanced Vegetation Index (EVI) are the most adequate for predicting species richness and diversity in mountainous grasslands with relatively good accuracies. Plant phenology and the choice of sensor affect the relationship between spectral information and species diversity variables.

The large‐scale restoration of fire and water regimes in Everglades National Park reveal little change in plant diversity along an elevational gradient

Quantifying the response of plant diversity to large‐scale restoration is essential for measuring management success. One of the world's largest restoration efforts began in 2000 in the Everglades ecosystem in Florida, United States, through the Comprehensive Everglades Restoration Plan. In coordination with ongoing fire management, this restoration effort aims to restore natural hydrologic and fire regimes in this dynamic ecosystem. Restored water and fire regimes in the Everglades interact along an elevational gradient between seasonally inundated marl prairie and frequently burned pine rockland on Long Pine Key in Everglades National Park. To determine the impact of management on plant community richness and composition, we resampled transects spanning the elevational gradient between marl prairie and pine rockland initially sampled prior to the implementation of current restoration efforts (circa 1997–1999). We measured percent plant cover and developed generalized linear mixed models to determine the effects of fire frequency, average water depth, and elevation on plant species richness and composition across the two time periods. Additionally, we used species‐level random effects to examine how individual species respond to each environmental variable. We failed to detect any systematic shifts in plant composition in response to fire and water management. However, we found that complex interactions between fire and water structure plant composition and maximize species richness along gradients of water depth and elevation, with low, moderate, and high burn frequencies increasing richness in wet, moderately wet, and dry sites, respectively.

Effects and driving factors of domestic sewage from different sources on nitrous oxide emissions in a bog

Abstract Direct sewage discharge may enhance soil nitrous oxide (N2O) emissions, worsening the greenhouse effect. However, the effects of sewage discharge into bogs on N2O flux, drivers and influencing mechanisms remain unclear. Additionally, investigating the impact of reclaimed water on N2O flux is important for bog replenishment and water shortage alleviation. This study simulated sewage from different sources into a bog and analyzed N2O fluxes, soil (organic carbon, total nitrogen, ammonium nitrogen, nitrate nitrogen, total phosphorus, available phosphorus, pH and electrical conductivity), plant (species richness and biomass) and microorganisms (ammonia-oxidizing archaea, napA, nirS, nirK and nosZ genes). Results showed that the reclaimed water did not significantly change N2O flux, while 50% tap water mixed with 50% domestic sewage and domestic sewage significantly increased the N2O flux. Among soil factors, available nitrogen and pH were key in influencing N2O flux. Among plant parameters, species richness was the primary factor affecting N2O flux. Nitrogen transformation functional genes contributed the most to the increase in the N2O fluxes, with an increase in domestic sewage input leading to a higher abundance of these genes and subsequent N2O emissions. Therefore, domestic sewage should be considered, as it significantly increases N2O emissions by affecting the soil, plants and microorganisms, thereby increasing the global warming potential. This study’s findings suggest that using treated reclaimed water for bog replenishment could be an environmentally friendly approach to wetland management.

Neglected puzzle pieces of urban green infrastructure: richness, cover, and composition of insect-pollinated plants in traffic-related green spaces

ContextIn cities, insect-pollinated vascular plants enhance environmental quality, support pollinators, and provide essential ecosystem services for citizens. However, floral communities associated with traffic-related green spaces are rarely considered valuable elements of urban green infrastructure (UGI).ObjectivesThe main objective of this work was to assess if traffic-related green spaces in Finland possess species-rich floral communities and can assist urban ecological restoration—converting degraded areas into functionally diverse ecosystems. Thus, we evaluated richness, cover, and community composition of insect-pollinated plants (emphasizing flowering ones) on traffic islands, parking lots, and road verges.MethodsThe assessment was performed during the mean flowering phenophase of insect-pollinated plants in the European boreal zone (July and August) using a standard quadrat (1 m2) placement method. We studied plants in urban and suburban locations of three highly populated (> 170 000 inhabitants) Finnish cities—Helsinki, Tampere, and Turku. There were 90 sampling sites with 15 replicates per location type in each city and five measurement replicates per green space (habitat) type. The species richness, cover, and composition were assessed in relation to location, habitat type, city, the average daily traffic (ADT), and distance to the road.ResultsUrban locations had lower total plant species richness and fewer indicator species (characterized only by a single indicator species) compared to suburban locations (characterized by five indicator species). Species richness of plants flowering during the time of the survey did not differ among locations. Traffic islands were richer habitats for flowering plants than road verges but did not differ from parking lots. Total vegetation cover and cover of insect-pollinated flowering plants increased with an increasing distance from the road. Vegetation cover differed among habitats being higher on road verges than on traffic islands irrespective of ADT. In all habitat types, the two most common flowering species were yarrow Achillea millefolium and autumn hawkbit Leontodon autumnalis which occurred at 70.2% and 67.8% of the sampling sites, respectively. However, the mean cover of the ten most common flowering species (when present) was low and varied between 1.5 and 9.5% per m2.ConclusionsSimilar richness of flowering plants (but not total plant species) in urban and suburban locations might indicate equal importance of ecosystem services provided by flowering plants in cities irrespective of location. Because traffic islands and parking lots contain rich plant communities, they should be better integrated into UGI and valued by city planners. Management intensity in terms of grass cuts should be ecologically justified. An increase in the number of insect-pollinated plant species in urban traffic-related green spaces might help to improve environmental quality in cities in terms of increasing pollinator biodiversity and reducing pollution.

Species richness: A pivotal factor mediating the effects of land use intensification and climate on grassland multifunctionality

Abstract Temperate seminatural grasslands harbour unique biodiversity, support livestock farming through forage production, and deliver many essential ecosystem services (ESs) to human society; they are highly multifunctional. However, temperate grassland ecosystems are also among the most threatened ecosystems on earth due to land use and climate changes. Understanding how biodiversity, climate and land use intensification impact grassland multifunctionality through complex direct and indirect pathways is critical to better anticipate the future of these fragile ecosystems. Here, we evaluate how local plant species richness (SR) modulates the effect of land use intensification and climate on grassland multifunctionality (using six key ESs: biomass productivity and stability, forage quality, carbon storage, pollination and local plant rarity) in the French Massif Central, the largest grassland in Western Europe. We sampled 100 grasslands with contrasted fertilization rates and SR, over large elevational and latitudinal gradients related to variation in mean annual temperature (MAT), and drought severity (DS), two key climate change drivers predicted to increase in the future. Using a confirmatory path analysis, we found that SR was the main driver of multifunctionality. We also found significant SR × MAT and SR × fertilization interactions suggesting that warm climate and high fertilization rates alter the biodiversity–ecosystem multifunctionality relationships. Furthermore, increasing temperature and fertilization indirectly influenced multifunctionality by decreasing SR and consequent multifunctionality in warm lowland and highly fertilized grasslands compared to colder montane grasslands or less fertilized ones. DS only impacted some ES individually (e.g. forage quality). Synthesis and applications: We identified species richness (SR) as a pivotal factor mediating the effects of land use intensification and climate on multifunctionality through both direct and indirect pathways. Failing to account for changes in SR could thus bias any prediction of, or aggravate, the effects of land use intensification and climate change on ecosystem services delivery in temperate grassland ecosystems. Considering that SR, mean annual temperature and fertilization are major proxies of three main global change drivers (biodiversity loss, climate change and land use intensification) our study may help to better anticipate the effect of multiple interacting global change drivers on grassland ecosystems.

Effect of Cipangopaludina chinensis and diversity of plant species with different life forms on greenhouse gas emissions from constructed wetlands

Greenhouse gas emissions (GHG) from Constructed wetlands (CWs) for treating wastewater have been largely focused on. Previous studies have demonstrated that plant species diversity significantly affects GHG. However, the effect of the diversity of plant species with different life forms and benthic organisms on GHGs from CWs remains unclear. In this study, we selected three common aquatic plant species with different life forms (submerged, free-floating, emergent) for diversity configuration (one, two, three species richness and all seven combinations; six replicates), with C. chinensis added to half the replicates. Results showed that: (1) in systems without C. chinensis, high plant species richness significantly increased CO2 emissions and GWPCH4+N2O+CO2, as well as CO2 emissions per unit N removal and GWPCH4+N2O+CO2 per unit N removal, the presence of Acorus calamus increased CO2 emissions by 77 % and GWPCH4+N2O+CO2 by 72 %, respectively, while the presence of Pistia stratiotes significantly reduced N2O emissions by 41 %; (2) in systems with C. chinensis, the presence of P. stratiotes significantly reduced N2O emissions by 73% and GWPnon-CO2 by 68 %, respectively; (3) plant species identify did not affect GWPCH4+N2O+CO2 per unit N removal and GWPnon-CO2 per unit N removal in systems with or without C. chinensis. In summary, adding C. chinensis affected the effect of plant species identity on GHGs from CWs. Thus, we suggested that establishing communities with low plant species richness and proper species (such as P. stratiotes) could improve pollutant removal rate (TIN) and reduce GHGs in CWs.

Drought and vegetation restoration lead to shifts in soil microbial diversity and co-occurrence networks in California coastal prairie

Abstract Background and aims Both drought and vegetation restoration can have dramatic effects on plant community composition, but how they influence soil microbial community diversity, structure, and co-occurrence networks remain less well known. Methods To better understand the regulatory mechanisms of drought and vegetation restoration on soil microorganisms, we planted 12 native species in precipitation manipulation experimental plots in an invaded coastal grassland in California, USA. We measured soil bacterial and fungal community composition by amplicon sequencing, and quantified plant species richness and coverage in the third experimental year. Results Our results showed that drought significantly altered soil bacterial diversity and composition; however, neither drought nor vegetation restoration had significant effects on fungal diversity and composition. The control plots had the most cooperative interactions (greatest number of correlations) among bacterial and/or fungal species, while drought plots yielded the most complex co-occurrence network with the highest modularity and clustering coefficient. Structural equation modeling revealed that plant species richness, net gains, and soil moisture played dominant roles in shaping bacterial community structure. Drought and bacterial community structure directly affected fungal community structure. Plant dominant species cover, common species cover, and bacterial diversity were the key drivers in regulating the microbial co-occurrence network complex. Conclusion We conclude that soil bacterial and fungal communities differ in their responses to abiotic and biotic environmental changes, which may weaken the interspecies interactions among soil microorganisms.

Spatial pattern of seed arrival has a greater effect on plant diversity than does soil heterogeneity in a grassland ecosystem

Background and AimsSpecies diversity is expected to increase with environmental heterogeneity. For plant communities, this pattern has been confirmed by numerous observational studies. Yet, experimental studies yield inconsistent results potentially because of how experiments create soil heterogeneity or because seeds were sown homogeneously. Using a field experiment, we tested how soil heterogeneity, plant spatial aggregation via seed arrival, and grain size influence plant species richness in a restored grassland.MethodsWe manipulated soil heterogeneity and seed arrival in 0.2 × 0.2 or 0.4 × 04 m patches within each 4.0 × 4.6 m plot and allowed community assembly to occur for 4 growing seasons.ResultsDespite quantifiable soil differences, soil heterogeneity did not impact total or sown species richness, but did weakly influence non-sown richness. Richness differences were driven by non-sown plant species that likely exhibited higher establishment in aggregated plots due to decreased interspecific competition and conspecific facilitation.ConclusionOur results suggest that fine-scale soil heterogeneity weakly affects prairie plant diversity, but heterogeneous plant spatial structure can have a stronger effect on diversity. These results suggest that plant colonization may be the primary source of environmental heterogeneity and may explain inconsistent results from soil heterogeneity experiments.

Biodiversity drives ecosystem multifunctionality in sandy grasslands?

Plant communities and soil microbiomes play a crucial role in regulating ecosystem multifunctionality (EMF). However, whether and how aboveground plant diversity, belowground soil microbial diversity and interactions with environmental factors affect EMF in sandy grasslands under climate change conditions is unclear. Here, we selected 15 typical grassland communities from the Horqin sandy grassland along temperature and precipitation gradients, using the mean annual temperature (AMT), mean annual precipitation (AP), soil temperature (ST), soil water content (SW) and pH as abiotic factors, and plant diversity (PD) and soil microbial diversity (SD) as biodiversity indicators. The effects of biodiversity and abiotic factors on individual ecosystem functions and EMF were studied. We found that PD and its components, plant species richness (SR), species diversity (PR) and genetic diversity (GD), had significant effects on aboveground biomass (AGB) and major factors involved in ecosystem nitrogen cycling (plant leaf nitrogen content (PLN) and soil total nitrogen content (STN)) (P < 0.05). Soil fungal diversity (FR) has a greater impact on ecosystem function than soil bacteria (BR) and archaea (ABR) in sandy grasslands and mainly promotes the accumulation of soil microbial carbon and nitrogen (MBC, MBN) (P < 0.05), STC and STN (P < 0.01). PD and two types of SD (FR and ABR) significantly regulated EMF (P < 0.01). Among the abiotic factors, soil pH and SW regulated EMF (P < 0.05), and SW and ST directly drove EMF (P < 0.05). PD drove EMF significantly and indirectly (positively) through soil pH and ST (P < 0.001), while SD drove EMF weakly and indirectly (negatively) through AP and PD (P > 0.05). PD was a stronger driving force on EMF than SD. These results improve our understanding of the drivers of multifunctionality in sandy grassland ecosystems.

Agriculturally Improved and Semi-Natural Permanent Grasslands Provide Complementary Ecosystem Services in Swedish Boreal Landscapes

Permanent grasslands cover more than a third of European agricultural land and are important for a number of ecosystem services. Permanent grasslands used for agriculture are broadly separated into agriculturally improved and semi-natural grasslands. High cultural and natural values linked to semi-natural grasslands are well documented. However, in boreal and hemi-boreal agricultural landscapes, less information is available about the areal coverage of improved permanent grasslands and their role for ecosystem service provision and biodiversity. In Sweden, grasslands are administratively separated into semi-natural (i.e., land that cannot be ploughed) or arable (i.e., improved temporary or permanent grassland on land that can be ploughed). We used data from a large-scale environmental monitoring program to show that improved permanent grassland (i.e., permanent grasslands on arable fields) may be a previously unrecognised large area of the agricultural land use in Sweden. We show that improved permanent grasslands together with semi-natural grasslands are both comparable but also complementary providers of a range of ecosystem services (plant species richness, plant resources for pollinators and forage amount for livestock production). However, as expected, semi-natural grasslands with the highest-level AESs (special values) show high species richness values for vascular plants, plants indicating traditional semi-natural management conditions and red-listed species. Improved permanent grasslands on arable fields are likely an underestimated but integral part of the agricultural economy and ecological function in boreal landscapes that together with high nature value semi-natural grasslands provide a broad range of ecosystem services.

Climate-induced tree-mortality pulses are obscured by broad-scale and long-term greening.

Vegetation greening has been suggested to be a dominant trend over recent decades, but severe pulses of tree mortality in forests after droughts and heatwaves have also been extensively reported. These observations raise the question of to what extent the observed severe pulses of tree mortality induced by climate could affect overall vegetation greenness across spatial grains and temporal extents. To address this issue, here we analyse three satellite-based datasets of detrended growing-season normalized difference vegetation index (NDVIGS) with spatial resolutions ranging from 30 m to 8 km for 1,303 field-documented sites experiencing severe drought- or heat-induced tree-mortality events around the globe. We find that severe tree-mortality events have distinctive but localized imprints on vegetation greenness over annual timescales, which are obscured by broad-scale and long-term greening. Specifically, although anomalies in NDVIGS (ΔNDVI) are negative during tree-mortality years, this reduction diminishes at coarser spatial resolutions (that is, 250 m and 8 km). Notably, tree-mortality-induced reductions in NDVIGS (|ΔNDVI|) at 30-m resolution are negatively related to native plant species richness and forest height, whereas topographic heterogeneity is the major factor affecting ΔNDVI differences across various spatial grain sizes. Over time periods of a decade or longer, greening consistently dominates all spatial resolutions. The findings underscore the fundamental importance of spatio-temporal scales for cohesively understanding the effects of climate change on forest productivity and tree mortality under both gradual and abrupt changes.

Plant phylogenetic diversity influences arthropod communities in tropical forest restoration plots

AbstractConsideration of plant phylogenetic diversity in ecological restoration carries substantial potential, as communities with a greater diversity of lineages with older evolutionary histories can increase the diversity of niches and thus are likely to recover larger species networks than communities clustered in specific clades with reduced variation in functional traits. In this study, we experimentally assessed how arthropod communities were affected by the phylogenetic diversity of a set of tropical tree species. We established 12 experimental restoration plots with either high or low plant phylogenetic diversity while maintaining constant the number of plant species. After 1 and 3 years, arthropods with different feeding habits (herbivores, predators, pollinators, and detritivores) were collected and identified as morphospecies or operational taxonomic units using metabarcoding techniques. We provide insights on the influence of plant phylogenetic diversity on arthropod abundance and species diversity, particularly among predator, pollinator, and detritivore common and dominant species, which increased with plant phylogenetic diversity. The trend, however, was the opposite for the diversity of herbivore common and dominant species, which decreased as plant phylogenetic diversity increased. These findings highlight the importance of considering plant species richness when designing restoration strategies, but also their evolutionary histories, as the same number of plant species can produce different outcomes for higher trophic levels, as a function of their phylogenetic relationships.Abstract in Spanish is available with online material.