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openCC0Jan 2018View details →

Streptomyces pathogen suppressive activity in plant communities varying in diversity:Plant host and plant diversity effects on rhizosphere microbial community composition, diversity, structure, and function.

Effects of plant host and plant community diversity on soil rhizosphere microbial community composition, diversity, structure, and function were explored in long-term experimental plots. Soil samples were collected from the rhizosphere of one of 4 target plants species (Andropogon gerardii, Schizachyrium scoparium, Lespedeza capitata, or Lupinus perennis) growing in 1, 4, 8, 16, or 32-species plots. Pathogen-suppressive activities of soil streptomycetes were determined for every sample. In addition, soil metagenomic analyses were performed targeting bacterial or streptomycete communities. Soil edaphic characteristics were determined for every sample. Analyses consider both the effects of plant host and plant community diversity on microbial community structure and function, and the relationships of diverse taxa with plant host, plant community diversity, and soil edaphic characteristics.

openCC0Jan 2018View details →

2007 pre-treatment soils pH, nutrients, texture:Nutrient Network: A cross-site investigation of bottom-up control over herbaceous plant community dynamics and ecosystem function.

This experiment is one implementation of a globally distributed experiment, known as the Nutrient Network. At Cedar Creek, as in over 70 other sites in grasslands around the world, the experiment aims to describe impacts of increased nutrients (nitrogen, phosphorus, potassium, sulfur and other metals) and decreased herbivory (removal of mammals by fencing). Two overarching questions are being explored with these manipulations: 1. To what extent are plant production and diversity co-limited by multiple nutrients in herbaceous-dominated communities? 2. Under what conditions do grazers or fertilization control plant biomass, diversity, and composition? By utilizing identical protocols at diverse grassland sites around the world, NutNet aims to uncover both the generalities in ecosystem functioning, and the contingencies or differences which can obscure those common mechanisms. In addition to the standard NutNet protocol, e247 includes an additional low Nitrogen gradient (1 gram Nitrogen per meter squared per year and 5 grams Nitrogen per meter squared per year in addition to the standard 10 grams Nitrogen per meter squared per year).

openCC0Feb 2018View details →

Multi-site grassland plant biomass, species richness and light (PAR):e247: Nutrient Network: A cross-site investigation of bottom-up control over herbaceous plant community dynamics and ecosystem function.

openCC0Aug 2021View details →

Nutrient Network Oak Litter Decomposition:Nutrient Network. A cross-site investigation of bottom-up control over herbaceous plant community dynamics and ecosystem function.

openCC0May 2022View details →

In situ soil respirations throughout the 2020 growing season across an N fertilization gradient:Nutrient Network. A cross-site investigation of bottom-up control over herbaceous plant community dynamics and ecosystem function.

opencc-zeroJul 2020View details →

Data from: Warming alters plant phylogenetic and functional community structure

<ol> <li>Climate change is known to affect many facets of the Earth's ecosystems. However, little is known about its impacts on phylogenetic and functional properties of ecological communities. </li> <li>Here we studied the responses of plant communities in an alpine grassland on the Tibetan Plateau to environmental warming across taxonomic, phylogenetic, and functional levels in a six-year multiple-level warming experiment. </li> <li>While low-level warming did not alter either plant species richness or phylogenetic/functional community structure, high-level warming significantly decreased species richness. Higher-level warming more strongly reduced soil moisture and caused stronger environmental filtering, consequently changing species composition and community structure. At the plant functional trait level, high-level warming promoted species turnover through altering the effects of traits such as plant height on species extinction and specific leaf area on species colonization. As a result, high-, but not low-level warming drove phylogenetic/functional community structure from overdispersion to randomness, by filtering out species that were functionally dissimilar and distantly related to the resident species. </li> <li>Synthesis. Our study provides evidence that the responses of plant phylogenetic and functional community structure to low warming differ from those in the future scenarios of increasing temperature. Importantly, the extinction of species that were functionally dissimilar and distantly related to the resident species contributed to alterations in plant community structure under high warming. Our study underscores the need to incorporate the phylogenetic and functional perspectives to gain a more complete understanding of community responses to climate warming.</li> </ol>

Functional gene categories differentiate maize leaf drought-related microbial epiphytic communities

The phyllosphere epiphytic microbiome is composed of microorganisms that colonize the external aerial portions of plants. Relationships of plant responses to specific microorganisms–both pathogenic and beneficial–have been examined, but the phyllosphere microbiome functional and metabolic profile responses are not well described. Changing crop growth conditions, such as increased drought, can have profound impacts on crop productivity. Also, epiphytic microbial communities provide a new target for crop yield optimization. We compared Zea mays leaf microbiomes collected under drought and well-watered conditions by examining functional gene annotation patterns across three physically disparate locations each with and without drought treatment, through the application of short read metagenomic sequencing. Drought samples exhibited different functional sequence compositions at each of the three field sites. Maize phyllosphere functional profiles revealed a wide variety of metabolic and regulatory processes that differed in drought and normal water conditions and provide key baseline information for future selective breeding.

Data from: Experimental demonstration of the importance of keystone communities for maintaining metacommunity biodiversity and ecosystem functioning

As local communities within a metacommunity may differ considerably in their contributions to biodiversity and ecosystem functioning, it has been suggested that conservation priority should be given to disproportionately important local communities (i.e., keystone communities). However, we know little about what characterizes a keystone community. Using laboratory protist microcosms as the model system, we examined how the environmental uniqueness and location of a local community affect its contributions to the metacommunities. We found that the removal of local communities with unique environmental conditions, which supported endemic species, reduced regional-scale diversity, qualifying them as regional-scale keystone communities. In addition, the local communities possessing unique environmental conditions had greater impacts on ecosystem functions, including biovolume production and particulate organic matter decomposition. We also found that keystone communities for biovolume production were not keystone for organic matter decomposition, and vice versa. Our study, therefore, demonstrates the important role of keystone communities in maintaining biodiversity and functioning of metacommunities.

Functional redundancy in natural pico-phytoplankton communities depends on temperature and biogeography

Biodiversity affects ecosystem function, and how this relationship will change in a warming world is a major and well-examined question in ecology. Yet, it remains understudied for pico-phytoplankton communities, which contribute to carbon cycles and aquatic food webs year-round. Observational studies show a link between phytoplankton community diversity and ecosystem stability, but there is only scarce causal or empirical evidence. Here, we sampled phytoplankton communities from two geographically related regions with distinct thermal and biological properties in the Southern Baltic Sea, and carried out a series of dilution/regrowth experiments across three assay temperatures. This allowed us to investigate the effects of loss of rare taxa and establish causal links in natural communities between species richness and several ecologically relevant traits (e.g. size, biomass production, and oxygen production), depending on sampling location and assay temperature. We found that the samples' bio-geographical origin determined whether and how functional redundancy changed as a function of temperature for all traits under investigation. Samples obtained from the slightly warmer and more thermally variable regions showed overall high functional redundancy. Samples from the slightly cooler, less variable, stations showed little functional redundancy, i.e. function decreased when species were lost from the community. The differences between regions were more pronounced at elevated assay temperatures. Our results imply that the importance of rare species and the amount of species required to maintain ecosystem function even under short-term warming may differ drastically even within geographically closely related regions of the same ecosystem.

Data from: Stream microbial communities and ecosystem functioning show complex responses to multiple stressors in wastewater

<div> Multiple anthropogenic drivers are changing ecosystems globally, with a disproportionate and intensifying impact on freshwater habitats. A major impact of urbanisation are inputs from wastewater treatment plants (WWTPs). Initially designed to greatly reduce nutrient loads, WWTPs increasingly release a multitude of micropollutants (i.e., synthetic chemicals) and organisms (including antibiotic resistant bacteria) to receiving environments. This pollution may have pervasive impacts on biodiversity and ecosystem services. Viewed through multiple lenses of macroecological and ecotoxicological theory, we combined field, flume, and laboratory experiments to determine the effects of wastewater on microbial communities and organic-matter processing using a standardized decomposition assay. Firstly, we conducted a mensurative experiment using 60 sampling locations above and below WWTP discharges in 20 Swiss streams. This showed that microbial respiration and decomposition rates were positively influenced by inputs of treated effluent via warming and nutrient enrichment, but with a notable exception: wastewater decreased the activation energy of decomposition, indicating a "slowing" of this fundamental ecosystem process in response to temperature. Secondly, next-generation sequencing of microbial communities indicated that community structure below WWTPs was altered, with significant compositional turnover, reduced fungal richness, and evidence of negative micropollutant influences. Thirdly, a series of flume experiments confirmed that although diluted wastewater generally has a positive influence on microbial-mediated processes, the negative effects of micropollutants are 'masked' by the addition of nutrients. Finally, cotton-strip transplant experiments suggested that wastewater-borne microbes enhance rates of decomposition. Taken together, our results affirm the multiple-stressor paradigm by showing that different aspects of wastewater (i.e., temperature, nutrients, microbes, and micropollutants) jointly influence ecosystem functioning in complex ways. Increased respiration rates below WWTPs potentially generate ecosystem 'disservices' via greater carbon evasion from streams and rivers. However, toxic effects of micropollutants may fundamentally alter ecological scaling relationships, indicating the need for a rapprochement between ecotoxicological and macroecological perspectives. </div>

Data from: Intraspecific variation in host plant traits mediates taxonomic and functional composition of local insect herbivore communities

Host plant phenotypic traits affect the structure of the associated consumer community and mediate species interactions. We compare herbivore assemblages from the canopy of the phenotypically variable tree Metrosideros polymorpha on Hawai'i Island. Multiple distinct varieties of M. polymorpha frequently co‐occur, with variation in morphological traits. Using this system, we identify host and insect traits that underlie patterns of herbivore abundance and quantify the strength of host‐insect trait interactions. The dataset includes host plant phenotypic traits (specific leaf area, leaf water content, foliar nutrients, trichome presence), as well as collection information. The dataset also contains the herbivorous insect community associated with this host plant, their abundances and life history traits. R code for analyses in this article is also included.

Effects of different functional structure parameters of plant communities on slope runoff in different periods of the year in semiarid grasslands

Research on sustainable use of water resources is needed to ensure food security, limit erosion, and prevent land degradation. Owing to the importance of water conservation to ecosystems, further research on the water conservation functions of different ecosystems is needed. Given the influence on water conservation functions, it is critical to identify environmental factors mediating slope runoff. In this study, the focal study area was the Yangjuangou catchment (36°42' N, 109°31' E) of the Loess Plateau in Shaanxi Province, China. Using a trait-based approach, a quantitative analysis was conducted to research effects of the functional structure parameters of plant communities on runoff of grass slopes for different periods of the year under differing rainfall intensity conditions. Results show that in mid-June, which represents the start of the growing season, effects of root traits on slope runoff decrease with increasing rainfall intensity. Slope runoff was found to be mainly affected by various plant functional traits in late July and aboveground parts of plants in early September. Given that few studies have focused on runoff processes using a trait-based approach at the community scale, this research can serve as a new reference for investigating the relationship between slope runoff and vegetation.

Data from: Above-belowground linkages of functionally dissimilar plant communities and soil properties in a grassland experiment

Changes in plant community composition can have long-lasting consequences for ecosystem functioning. However, how the duration of plant growth of functionally distinct grassland plant communities influences abiotic and biotic soil properties and thus ecosystem functions is poorly known. In a field experiment, we established identical experimental subplots in two successive years comprising of fast- or slow-growing grass and forb community mixtures with different forb:grass ratios. After one and two years of plant growth, we measured above- and belowground biomass, soil abiotic characteristics (pH, organic matter, soil nutrients), soil microbial properties (respiration, biomass, community composition), and nematode abundance. Fast- and slow-growing plant communities did not differ in above- and belowground biomass. However, fast-and slow-growing plant communities created distinct soil bacterial communities, whereas soil fungal communities differed most in 100% forb communities compared to other forb:grass ratio mixtures. Moreover, soil nitrate availability was higher after two years of plant growth, whereas the opposite was true for soil ammonium concentrations. Furthermore, total nematodes and especially bacterial-feeding nematodes were more abundant after two years of plant growth. Our results show that plant community composition is a driving factor in soil microbial community assembly and that the duration of plant growth plays a crucial role in the establishment of plant community and functional group composition effects on abiotic and biotic soil ecosystem functioning under natural field conditions.

opencc-zeroSep 2020View details →

Data from: Taxonomic divergence and functional convergence in Iberian spider forest communities: insights from beta diversity partitioning

Aim The main aims were to determine: i) the relative contribution of species replacement and richness difference components to overall taxonomic (TDβ) and functional (FDβ) beta diversity of spider communities; ii) the degree to which TDβ and FDβ components can be explained by the environmental or geographic predictors; iii) whether FDβ components were lower than expected given the underlying TDβ variation. Location This study was carried out in 22 oak forest sites across the Iberian Peninsula. The area comprises two biogeographic regions, Eurosiberian (North) and Mediterranean (Centre and South). Methods Spiders were sampled using a standardized protocol. A species x traits matrix was constructed. Total taxonomic (TDβtotal) and total functional (FDβtotal) beta diversity were calculated, by pairwise comparisons, and partitioned into their replacement (βrepl) and richness difference (βrich) components. Mantel tests were used to relate taxonomic and functional dissimilarity with environmental and geographic distances. A spatial eigenfunction model was constructed and the variation of TDβ and FDβ explained by environment and geographic predictors was quantified. Null models were used to test if FDβ was higher or lower than expected given TDβ. Results βrepl was the dominant component contributing to 84.2% and 72.8% for TDβtotal and FDβtotal, respectively. TDβtotal and FDβtotal (and their replacement components) were higher between- than within-biogeographic regions. TDβtotal and TDβrepl were positively correlated with environmental and geographic distances, even when controlling for a biogeographic effect, but their functional counterparts were only correlated with environmental distance. Variation partitioning showed that pure environmental and spatially structured environmental effects had a small contribution to beta diversity, except for TDβrich. The observed slopes of the regressions of FDβtotal and FDβrepl in relation to environmental distance were slower than the null model expectations. Main conclusions Spider' assemblages variation was mainly determined by the replacement, and not the net loss, of species and traits. TDβ was influenced by niche filtering and dispersal limitation, whereas FDβ was mainly generated by niche filtering. A high level of functional convergence among spider communities, despite the high taxonomic divergence, revealed the signal of replacement of species performing similar functions across sites.

opencc-zeroDec 2018View details →

Data from: Soil functional responses to drought under range-expanding and native plant communities

1. Current climate warming enables plant species and soil organisms to expand their range to higher latitudes and altitudes. At the same time, climate change increases the incidence of extreme weather events such as drought. While it is expected that plants and soil organisms originating from the south are better able to cope with drought, little is known about the consequences of their range shifts on soil functioning under drought events. 2. Here, we test how range-expanding plant species and soil communities may influence soil functioning under drought. We performed a full-factorial outdoor mesocosm experiment with plant communities of range expanders or related natives, with soil inocula from the novel or the original range, with or without summer drought. We measured litter decomposition, carbon mineralization and enzyme activities, substrate-induced respiration, and the relative abundance of soil saprophytic fungi immediately after drought and at 6 and 12 weeks after rewetting. 3. Drought decreased all soil functions regardless of plant and soil origin except one; soil respiration was less reduced in soils of range-expanding plant communities, suggesting stronger resistance to drought. After rewetting, soil functioning responses depended on plant and soil origin. Soils of native plant communities with a history of drought had more litter mass loss and higher relative abundance of saprophytic fungi than soils without drought and soils of range expanders. Functions of soil from range expanders recovered in a more conservative manner than soils of natives, as litter mass loss did not exceed the control rates. At the end of the experiment, after rewetting, most soil functions in mesocosms with drought history did not differ anymore from the control. 4. We conclude that functional consequences of range expanding plants and soil biota may interact with effects of drought, and that these effects are most prominent during the first weeks after rewetting of the soil.