Find research datasets worth reusing

Search datasets from major research repositories and use ShareScore to quickly assess how well each record supports discovery, access, and reuse.

955

datasets available to search

ShareScore release 0.9.0

Dataset results

955 results for “Subtropical”

Learn how ShareScore rates datasets ↗

dryad36/100

Data from: Nitrogen reduction causes shifts in winter and spring phytoplankton composition and resource use efficiency in a large subtropical lake in China

Aquatic ecosystems occasionally show ecological thresholds, defined as the point at which there is a sudden shift in production, trait or biomass or where changes in an environmental driver create nonlinear responses at the ecosystem level. Previous studies of lakes have mainly focused on how reduction in particularly phosphorus (P) concentrations helps to create a shift in lakes from a turbid to a clear state (re-oligotrophication), whereas the effect of nitrogen (N) reduction is less well studied. Here, by analysing a 28-year monthly monitoring dataset (from December 1991 to November 2019) from the subtropical, large eutrophic Lake Taihu, China, we identified a sudden shift in phytoplankton biomass and composition that coincided with a pronounced change in ecosystem functions, for example, resource use efficiency (RUE), during a period with reduction of the external nutrient loading. The changes were particularly strong in winter–spring where a sudden decrease in N concentrations was accompanied by a sudden increase in diatom biomass and phytoplankton RUE and a shift from green algae and flagellate co-dominance to dominance of diatoms. Structural equation modelling further indicated that ammonium reduction led directly to increases in winter–spring phytoplankton RUE and diatom biomass. Repeated fish stocking likely also contributed to the changes in biomass and RUE. Our study provides new insight into the ecological responses to N loading reduction and contributes to the understanding of lake responses to early re-oligotrophication, which was pronounced mainly in the colder seasons in subtropical Lake Taihu, similar to findings in the early phase of re-oligotrophication in numerous temperate lakes.

opencc-zeroJun 2023View details →

dryad36/100

Data from: Litter quality controls tradeoffs in soil carbon decomposition and replenishment in a subtropical forest

Species-rich forests can produce litter of varying carbon (C) and nitrogen (N) composition (i.e., quality), which can affect decomposition and play a central role in long-term soil organic carbon (SOC) accumulation. However, how differences in litter quality affect SOC decomposition and formation remains unclear over the full litter decomposition trajectory. We followed the in-situ complete decomposition of added 13C-labelled high- (low C:N) and low-quality (high C:N) leaf-litter and its effect on particulate (POM) and mineral-associated (MAOM) organic matter fractions over two years in a natural subtropical forest. We found that during early stages of decomposition, low-quality litter inputs decreased SOC via a positive priming effect (i.e., new C inputs favored decomposition of native SOC), but these SOC losses were offset by SOC gains observed via a negative priming effect during decomposition of high-quality litter. In contrast, this pattern reversed during late stages of decomposition—SOC losses via a positive priming effect induced by high-quality litter were offset by SOC gains via a negative priming effect induced by low-quality litter. Over the full decomposition of litter, both high- and low-quality litter stimulated microbial breakdown of SOC tied to POM, but also replenished more persistent SOC that associated with soil minerals (MAOM). Altogether, we observed that low-quality litter formed twice as much new SOC as high-quality litter (24% vs. 12% of added litter-C). We extend the notion of the priming effect from primarily a negative role promoting losses of native SOC, to a functional role that can replenish persistent SOC. Synthesis. Our measurements raise the possibility that, in species-rich forests, high- and low-quality litter decomposition play opposite but dynamically complementary roles in renewing POM—both by inducing its decomposition and formation—while exclusively favoring MAOM formation, which can help explain how differences in litter quality favor SOC accumulation and persistence. Global change factors that shift plant community composition may ultimately affect the fate of soil C, as changes in litter quality may force soil transitions from sinks to sources or sources to sinks of atmospheric CO2.

opencc-zeroJul 2023View details →

dryad36/100

An invasive appetite: Combining molecular and stable isotope analyses to reveal the diet of introduced house mice (Mus musculus) on a small, subtropical island

House mice (Mus musculus) pose a conservation threat on islands, where they adversely affect native species' distributions, densities, and persistence. On Sand Island of Kuaihelani, mice recently began to depredate nesting adult mōlī (Laysan Albatross, Phoebastria immutabilis). Efforts are underway to eradicate mice from Sand Island, but knowledge of mouse diet is needed to predict ecosystem response and recovery following mouse removal. We used next-generation sequencing to identify what mice eat on Sand Island, followed by stable isotope analysis to estimate the proportions contributed by taxa to mouse diet. We collected paired fecal and hair samples from 318 mice between April 2018 to May 2019; mice were trapped approximately every eight weeks among four distinct habitat types to provide insight into temporal and spatial variation. Sand Island's mice mainly consume arthropods, with nearly equal (but substantially smaller) contributions of C3 plants, C4 plants, and mōlī. Although seabird tissue is a small portion of mouse diet, mice consume many detrital-feeding arthropods in and around seabird carcasses, such as isopods, flesh flies, ants, and cockroaches. Additionally, most arthropods and plants eaten by mice are non-native. Mouse diet composition differs among habitat types but changes minimally throughout the year, indicating that mice are not necessarily limited by food source availability or accessibility. Eradication of house mice may benefit seabirds on Sand Island, but it is unclear how arthropod and plant communities may respond and change. Non-native and invasive arthropods and plants previously consumed (and possibly suppressed) by mice may be released post-eradication, which could prevent recovery of native taxa. Comprehensive knowledge of target species' diet is a critical component of eradication planning. Dietary information should be used both to identify and to monitor which taxa may respond most strongly to invasive species removal and to assess if proactive, pre-eradication management activities are warranted.

opencc-zeroJul 2023View details →

zenodo36/100

Soil microbial community, dissolved organic matter and nutrient cycling interactions change along an elevation gradient in subtropical China

This table contains data on soil dissolved organic matter at different elevations in Wuyi Mountain, China, which is attached to the manuscript submitted to Journal of Environmental Management (Manuscript ID:JEMA-D-23-01912).

opencc-by-4.0Dec 2022View details →

zenodo36/100

Date set for the manuscript: Exploring the temporal dynamics of methane ebullition in a subtropical freshwater reservoir

The dataset supports the findings of the manuscript entitled ‘Exploring the Temporal Dynamics of Methane Ebullition in a Subtropical Freshwater Reservoir’. The results of the manuscript are based on continuous in-situ measurements conducted at Passaúna Reservoir, located in the southern part of Brazil (South America). The monitoring was carried out from 2017 to 2020, during which a comprehensive set of environmental variables was obtained from various studies. The primary objective of the manuscript was to comprehend the temporal dynamics of ebullition flux in the reservoir. Therefore, time series data of ebullition and relevant environmental variables were analyzed across different time scales, ranging from minutes to daily resolutions. Statistical and data driven models were tested to predict ebullition at varying time scales, considering the influence of environmental variables. The findings are discussed in the manuscript. Here, xlsx files and Matlab scripts are provided. The xlsx files contain time series data for environmental variables ('Environmental_Variables_TimeSeries') and ebullition flux ('Ebullition_Flux_TimeSeries'). Separate sheets were utilized for different time intervals, namely 5 minutes (dt=5min), 10 minutes (dt=10min), 1 hour (dt=1hr), and 1 day (dt=1d). Explanations and units are provided within the column labels, while 'NaN' denotes missing data. Matlab scripts for all the empirical models that were tested, as outlined in the manuscript's supporting information (Tables S1 and S2), have been made available (detailed in the following table). These scripts were developed using MatLab R2023a. <table> <tbody> <tr> <td> File (.m) </td> <td> Description </td> </tr> <tr> <td> Main scripts </td> </tr> <tr> <td> TableS1_Empirical_Models_Literature </td> <td> Empirical models from the literature tested. (Table S1 in the manuscript) </td> </tr> <tr> <td> TableS2_FirstPart_Reffited_Models </td> <td> Empirical models from the literature refitted. (Table S2 in the manuscript) </td> </tr> <tr> <td> TableS2_SecondPart_New_Models </td> <td> New empirical models implemented. (Table S2 in the manuscript) </td> </tr> <tr> <td> TableS2_SecondPart_New_Models_GAM_Timescales </td> <td> Generalized additive models (GAM) applied to predict ebullition at different timescales. (Table S2 in the manuscript). </td> </tr> <tr> <td> PredictedR2_GAM_models </td> <td> Calculate the predicted R-squared for GAM. </td> </tr> <tr> <td> Functions (need for the main scripts) </td> </tr> <tr> <td> load_TimeSeries </td> <td> Import time series of environmental variables from excel sheets into MatLab. </td> </tr> <tr> <td> load_EbullitionTS </td> <td> Import time series of ebullition from excel sheets into MatLab. </td> </tr> <tr> <td> units_description </td> <td> Description containing units of the variables. </td> </tr> <tr> <td> Bin_xdata </td> <td> Creates data binning of X and Y based on X data. </td> </tr> <tr> <td> RelativeError </td> <td> Calculate the relative error of accumulated flux between measured and simulated. </td> </tr> <tr> <td> ANN5Neurons_Retrained_Deshmukh2014 </td> <td> Trained Artificial Neural Network based on the ANN proposed by Deshmukh et al. (2014). </td> </tr> <tr> <td> ANN_Passauna_20Neurons </td> <td> Trained Artificial Neural Network with the addition of more environmental variables. </td> </tr> </tbody> </table>   Financial support The field measurements were financed by the German Federal Ministry of Education and Research (BMBF, Grant 02WGR1431A), in the framework of the research project MuDak-WRM (https://www.mudak-wrm.kit.edu). This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001. Tobias Bleninger received productivity stipend from the National Council for Scientific and Technological Development (CNPq, grant no. 312211/2020-1, call no. 09/2020). Michael Männich received productivity stipend from the National Council for Scientific and Technological Development (CNPq, grant no. 308744/2021-7, call no. 04/2021). Andreas Lorke received financial support from the German Research Foundation (DFG, grant number LO1150/16-1).

opencc-by-4.0Aug 2023View details →

dryad36/100

Root-centric β diversity reveals functional homogeneity while phylogenetic heterogeneity in a subtropical forest

Root-centric studies have revealed fast taxonomic turnover across root neighborhoods, but how such turnover is accompanied by changes in species functions and phylogeny (i.e. β diversity), which can reflect the degree of community-wide biotic homogenization, remains largely unknown, hindering better inference of below-ground assembly rules, community structuring, and ecosystem processes. We collected 2480 root segments from 625 0–30 cm soil profiles in a subtropical forest in China. Root segments were identified into 143 species with DNA-barcoding with six root morphological and architectural traits measured per species. By using the mean pairwise (Dpw) and mean nearest neighbor distance (Dnn) to quantify species ecological differences, we tested the non-random functional and phylogenetic turnover of root neighborhoods that would lend more support to deterministic over stochastic community assembly processes, examined the distance-decay pattern of β diversity, and finally partitioned β diversity into geographical and environmental components to infer their potential drivers of environmental filtering, dispersal limitation, and biotic interactions. We found that functional turnover was often lower than expected given the taxonomic turnover, whereas phylogenetic turnover was often higher than expected. Both functional and phylogenetic Dpw (e.g. interfamily species) turnover exhibited a distance-decay pattern, likely reflecting limited dispersal or abiotic filtering that leads to the spatial aggregation of specific plant lineages. Conversely, phylogenetic Dnn (e.g. intrageneric species) exhibited an inverted distance-decay pattern, likely reflecting strong biotic interactions among spatially and phylogenetically close species leading to phylogenetic divergence. While the spatial distance was generally a better predictor of β diversity than environmental distance, the joint effect of environmental and spatial distance usually overrode their respective pure effects. These findings suggest that root neighborhood functional homogeneity may somewhat increase forest resilience after disturbance by exhibiting an insurance effect. Likewise, root neighborhood phylogenetic heterogeneity may enhance plant fitness by hindering the transmission of host-specific pathogens through root networks or by promoting interspecific niche complementarity not captured by species functions. Our study highlights the potential role of root-centric β diversity in mediating community structures and functions largely ignored in previous studies.

opencc-zeroOct 2023View details →

dryad36/100