This Wang_2022_DATA_README.txt file was generated on 2022-06-24 by Jiang Wang GENERAL INFORMATION 1. Title of Dataset: Data from: Darwin¡¯s naturalization conundrum reconciled by changes of species interactions. 2. Author Information Corresponding Investigator Name: Dr Xiao-Yan Wang Institution: School of Life Science/Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, China Email: wxy3470117@163.com Co-investigator 1 Name: Dr Jiang Wang Institution: School of Life Science/Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, China Email: wangjiang@tzc.edu.cn Co-investigator 2 Name: Dr Shao-peng Li Institution: Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, China Email: spli@des.ecnu.edu.cn Co-investigator 3 Name: Dr Yuan Ge Institution: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, China Email: yuange@rcees.ac.cn Co-investigator 4 Name: Dr Song Gao Institution: School of Life Science/Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, China Email: lygs2008@163.com Co-investigator 5 Name: Tong Chen Institution: School of Life Science/Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, China Email: 925862127@qq.com Co-investigator 6 Name: Prof Fei-Hai Yu Institution: School of Life Science/Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, China Email: feihaiyu@126.com 3.Date of data collection: 2016 4.Geographic location of data collection: Taizhou, Zhejiang, China 5.Funding sources that supported the collection of the data: The National Natural Science Foundation of China (31870504, 32071527, 42177274, 31971553), Natural Science Foundation of Zhejiang Province (LY22C030001, LTY22C030004), and Taizhou University National Funds for Distinguished Young Scientists (2017JQ005). 6. Recommended citation for this dataset: Wang et al. (2022), Data from: Darwin¡¯s naturalization conundrum reconciled by changes of species interactions, Dryad, Dataset DATA & FILE OVERVIEW 1. Description of dataset Experimental plant communities with five levels of species richness (1, 2, 4, 8 and 16 species) were constructed at Taizhou University (28¡ã39¡äN, 121¡ã23¡äE) in Taizhou, Zhejiang Province, China. The species pool consisted of 16 native herbaceous species (Antenoron filiforme, Achyranthes aspera, Solanum nigrum, Penthorum chinense, Sesbania cannabina, Patrinia scabiosaefolia, Eclipta prostrata, Polygonum chinense, Bidens pilosa, Perilla frutescens, Artemisia migoana, Justicia procumbens, Persicaria lapathifolia, Lolium perenne, Cichorium intybus and Medicago sativa) were selected to stimulate natural communities. Patrinia scabiosaefolia (Valerianaceae), Achyranthes aspera (Amaranthaceae), Solanum nigrum (Solanaceae) and Artemisia migoana (Asteraceae) are usually dominant species. We constructed a total of 46 communities with different species compositions: one monoculture for each of the 16 species, 10 two-species mixtures, 10 four-species mixtures, 9 eight-species mixtures and one 16-species mixture. Each of the two-, four- or eight-species mixtures had a different species composition, and the species were randomly chosen from the species pool. All the 45 communities of the one-, two-, four- and eight-species mixture were replicated six times, and the community of the 16-species mixture was replicated 30 times, resulting in a total of 300 communities. The six replicates of the 45 communities were randomly assigned to the six combinations of three drought intensity treatments (no, moderate and intensive drought) and two invasion treatments (with or without an exotic plant invasion; as described in the next two sections); the 30 replicates of the 16-species mixture were also randomly assigned to the six treatment combinations of drought and invasion, with five replicates each. We harvested the communities in all containers in October 2016. The biomass of most species almost reached to the highest value in October. In each container, aboveground living plants were sorted to species, dried to constant mass at 80¡ãC and weighed. As some pathogens seemed to specifically infect Medicago sativa, no plants of this species survived at the end of the experiment. As the monocultures of M. sativa had no living plants, these containers (one in each of the six treatment combinations of drought and invasion) were not included in data analysis. Consequently, there was a final sample of 49 plots in each of six treatments. 2. File: Name: Wang_2022_data.xlsx Description: All data of this study. METHODOLOGICAL INFORMATION ¡¡¡¡ The experimental plant communities were constructed in plastic containers (72 cm long ¡Á 64 cm wide ¡Á 42 cm deep) with five draining holes at the bottom. Each container was first filled with a 27 cm layer of a soil (total N: 0.763 ¡À 0.104 g kg?1, total P: 0.216 ¡À 0.047 g kg?1, mean ¡À SE, n = 10) and then a 10 cm layer of a mixture of the soil and a nutrient-rich potting compost (Appendix S1: Table S3) at a volume ratio of 1:1 (total N: 4.612 ¡À 0.456 g kg?1, total P: 0.802 ¡À 0.189 g kg?1, mean ¡À SE, n = 10). The soil was collected in a mountain area near Taizhou, and it was classified as the fine loamy mixed semiative mosic humic hapludults soil. The soil-compost mixture layer was added to facilitate seed germination and seedling establishment. ¡¡¡¡In December 2013, we sowed a total of 800 seeds in each container and determined seed number of each species in a container by dividing 800 by species number. One month after germination, vigorous seedlings of each species with similar height were selected and excess seedlings were removed. Thus, at the start of the experiment, plant density was maintained at 32 seedlings per container, and each species was represented by the same number of seedlings (e.g. for four-species mixtures, there were eight seedlings for each species). The 32 seedlings were spatially evenly distributed in the container, and seedlings of the same species were not adjacent, if possible. In each container, we also removed undesired seedlings, i.e. those not belonging to the originally sown species. All the containers were randomly placed inside a plastic rain shelter in Taizhou University, which was open at the bottom sides to allow air to be ventilated. ¡¡¡¡Using automatic drip irrigation systems, we set up three drought treatments (no, moderate and intensive drought) via the control of the irrigated time. To account for seasonal variation of evapotranspiration, Soil water content of 20 containers randomly selected for each of six combined treatments were measured with a ProCheck analyzer (Decagon, Pullman, Washington, USA). Data collected using this ProCheck analyzer were adjusted based on the traditional way of measuring gravimetric soil water content. The irrigated time was adjusted based on the data of these measurements. For the treatment of no drought, the irrigated time was set to 20-35 minutes, and gravimetric soil water content (15.5¨C19.8%) was maintained similar to that of plant communities of the mountain areas around Taizhou. For the treatments of moderate and intensive drought, the irrigated time was 50% (gravimetric soil water content ranging from 12.4-15.4%) and 25% (gravimetric soil water content ranging from 10.0-12.6%) of that in the no drought treatment, respectively. Depending on the weather conditions, plant communities in the containers were irrigated once a day between May and September, once every other day between March and April and between October and December, and once every week between January and February. The drought treatments started on March 12, 2015, i.e. 16 months after the plants were initially sowed. In December 2015, for half (150) of the experimental communities, 50 seeds of the invasive annual herb S. subulatum were evenly sown in each plot. We also established four monocultures of the invader under each drought treatment by sowing 50 seeds of S. subulatum, and all of the survived individuals were left. ¡¡¡¡We used Phylocom v.4.2 software to calculate the phylogenetic distance of S. subulatum to the natives using three commonly sequenced genes from the GenBank: rbcL, matK and ITS. Furthermore, the above genetic distances were weighted by the relative abundance of the natives, as metrics to represent the phylogenetic distance between the invader and a recipient community. The MPD was calculated as follows: ¡¡ where n is number of species in a native community, PDi is phylogenetic distance of S. subulatum to species i, and RPDi is relative abundance of species i in the native communities. MPD was respectively calculated by three weighted methods: (1) MPD calculated by original planted density in April 2014; (2) MPD weighted by plant density in October 2014 (before the drought treatment and the invasion treatment), which is independent to drought and invasion treatments; (3) MPD weighted by biomass in October 2016 (at the end of the experiment). The complementarity and selection effect among native species were calculated following the additive partitioning method of Loreau and Hector (2001). The selection effect, , was calculated as the covariance between monoculture yield of species (M) and their change in relative yield in the mixture () multiplied by N of the mixture. The complementarity effect for a given number of species (N) is quantified as , whereis the mean value of monoculture yield (biomass) across all species and is the mean value of relative yield (aboveground biomass) across all species in the mixture. ¡¡Biomass deviation (D) of mixtures was calculated based on its monoculture biomass following the method of Loreau and Hector (2001): ¡¡¡¡ where was observed biomass of species i in the mixture under the drought level j, Ei was expected biomass of species i in the mixture, i.e. simply the monoculture biomass multiplied by the initial proportion (original planted density in April 2014) of the species in the mixture under the drought level j, and n is the number of species included in the mixture. Biomass deviation (Di) of each dominant species (having the greatest biomass in a community) and non-dominant species in mixtures was also calculated as Di = (Oi - Ei)/Ei. ¡¡The relative neighbour effect (RNE) was calculated following : ¡¡ where Xt is invader biomass for each plot with native species in a given drought treatment, Xc is average biomass of the invader monocultures in the same drought treatment, and x is the highest value of Xt and Xc. AMF colonization rates of hyphae, vesicles and arbuscules in roots were quantified using the line-intersect method after clearing roots in 10% KOH and staining in 0.05% trypan blue (McGonigle et al. 1990). For S. subulatum in each container, at least 200 intersects of 30 root segments of around 1 cm long were scored under a light microscope at 200 ¡Á magnification. AMF colonization rate was calculated by dividing the infected intersects by the observed 200 intersects. High colonization rate means more easily colonized by AMF. DATA-SPECIFIC INFORMATION FOR: Wang_2022_data.xlsx 1. Number of variables: 15 2. Number of cases/rows: Sheet 1 'data': 148 Sheet 2 'biomass': 682 Sheet 3 'phylogenetic distance': 17 3. Variable List: Plot_number: Plot number Species_richness: Species number in plot Drought_Intensity: 1 No drought, 2 Moderate drought, 3 Intensive drought Dominant_Species: 1 species Artemisia migoana exists, 0 species Artemisia migoana does not exist Cichorium_intybus: 1 species Cichorium intybus exists, 0 species Cichorium intybus does not exist MPD_Oct_2016: Mean phylogenetic distance of between the invader and a recipient community at Oct 2016. MPD_April_2014: Mean phylogenetic distance of between the invader and a recipient community at April 2014. MPD_Oct_2014: Mean phylogenetic distance of between the invader and a recipient community at Oct 2014. Log_of_invader biomass+1: log value of (invader biomass+1) Log_of_native biomass+1: log value of (native species biomass+1) AMF_colonization_rate: AMF colonization rate RNE: The relative neighbour effect. Complementarity_effect: Complementarity effect among native species. Selection_effect: Selection effect among native species. Biomass_deviation_of_communities: Biomass deviation of mixtures. Species_Name: Species name. Aboveground_biomass_g: Aboveground biomass of plant species (g). Seedling_number_Oct_2014: The number of surviving seedlings on Oct 2014. Native_species: Name of native species. Invader: Name of invasive species. Phylogenetic_distance: phylogenetic distance of S. subulatum to native species. 4. Missing data codes: ¡¡N/A: not applicable 5. Abbreviations used: MPD: Mean phylogenetic distance ¡¡RNE: Relative neighbour effect 6. Other relevant information: not applicable