These methods, instrumentation and/or protocols apply to all data in this dataset:| Methods and protocols used in the collection of this data package |
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| Description: |
Demographic data were collected in fifty-six 3 m x 3 m plots placed at four different sites representing both naturally occurring and introduced Shortia populations and situated along a resource availability gradient. Plots were systematically placed to capture clusters of individuals within Shortia populations at each site. Study populations consisted of 32 individuals transplanted across 16 plots cleared of all competing vegetation within the Coweeta Basin (Coweeta from hereon; Otto, NC; 35°03′N 83°25′W; established in 2016), 216 individuals growing in 18 plots representing introduced populations at the Highlands Biological Station (Highlands from hereon; Highlands, NC; 35°03′N, 83°25′W; established in 1960), 72 individuals growing in four plots representing introduced populations within Oconee State Park (Oconee from hereon; Mountain Rest, SC; 34°86′N, 83°10′W; established in 1980), and 216 individuals growing in 18 plots representing natural populations within Devil’s Fork State Park, (Devil’s Fork from hereon; Salem, SC; 34°95′N, 82°94′W). Due to their elevation and geographical location, transplant populations at Coweeta and Highlands are located outside the natural climate envelope of Shortia (Prince, 1947; Vivian, 1967).
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Sampling
At Devil’s Fork, Oconee, and Highlands, we marked twelve individuals in each plot with colored zip ties (except at Coweeta, which only had two individuals per plot) representing seedlings, vegetative, and flowering plants (N = 536). Initial data collection began in May 2017. For each tagged plant, we recorded rosette size (length x width, cm) and number of mature capsules. In June 2017, we estimated seed production for each plot at each site by harvesting 18 ripe capsules from individual plants growing just outside of the study plots at Highlands. Each capsule was dissected, and the number of seeds counted to obtain an average number of seeds per capsule. Total estimated seed production was obtained by multiplying the average number of seeds per capsule by the number of capsules on each individual in each plot. We then estimated the recruitment probability for each site by dividing the total number of new recruits recorded in 2018 at each site by the total estimated seed production in 2017 at each site (Caswell, 2001; Drake, 2019; Hüls et al., 2007). Subsequent data collection occurred in late-July and early-August 2018. In each plot we relocated marked plants and recorded whether they had survived or died. For surviving plants, we remeasured rosette size and number of mature capsules. We also recorded all new vegetative clones (ramets) and measured their rosette size and number of capsules in the same manner as described above. All new seedlings that appeared inside the plots were also counted and measured as described above.
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| | Description: |
Plots
Plots were systematically placed to capture clusters of individuals within Shortia populations at each site.
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Plant Measurements -- We marked twelve individuals in each plot with colored zip ties (except at Coweeta, which only had two individuals per plot) representing seedlings, vegetative, and flowering plants (N = 536). Initial data collection began in May 2017. For each tagged plant, we recorded rosette size (length x width, cm) and number of mature capsules.
| | Instrument(s): | Centimeter ruler and calipers |
| | Description: |
Abiotic Measurements -- Abiotic Measurements -- We measured soil temperature continuously (5-cm depth), volumetric soil moisture twice per week (7 cm depth) (Summer 2016), and photosynthetically active radiation (PAR; wavelength: 400–700 nm) twice per month following full canopy leaf out (July 2017)
| | Instrument(s): | iButton datalogger, Field Scout TDR 100 probe (Spectrum Technologies, Aurora, IL, USA), 0.5 m handheld PAR ceptometer (Decagon Devices, Pullman, WA, USA) |
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Soil Measurements -- Ten soil cores were collected at random from the upper 10 cm of mineral soil using a 2.2-cm diameter soil probe. Cores were composited by plot, sieved (< 2 mm), and air dried prior to subsampling for determination of pH (1:1 mass: H2O volume) and carbon (C) and nitrogen (N) concentrations.
| | Instrument(s): | Thermo Scientific Orion 3 Star pH Benchtop with Orion 8157BNUMD probe, Costech 4010 CHNSO Elemental Analyzer (Costech Analytical Technologies, Valencia, CA, USA) |
| | Description: |
Soil Nutrient Availability -- Three pairs of ion-exchange resin strips (6.0 cm x 2.5 cm) in the mineral soil at 0 – 6 cm depth and a minimum distance of 0.5 m from one another in each subplot in June 2016 (Schoenau et al., 1993; Susfalk & Johnson, 2002). Resin strips were left in the ground for 30 days (Coweeta) and 25 days (Mainspring). Upon removal, resin strips were rinsed with DDI water and extracted in 2 mol/L KCl. Extractions were filtered through 0.7-μm Whatman filter paper and frozen (-20 °C) until analysis. We analyzed extracts for NH4-N using the phenolate method, NO3-N using a cadmium column reduction method, and PO4 using the molybdenum blue method.
| | Instrument(s): | Lachat QuikChem 8500 (Hach Company, Loveland, CO, USA) |
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Micro-Dumas combustion
Total carbon
Total nitrogen
| | Instrument(s): | Flash EA 1112 CN Analyzer |
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0.01N CaCl2 solution
soil pH
| | Instrument(s): | Thermo Scientific Orion 3 Star pH Benchtop |
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Cation exchange capacity
phosphorus
| | Instrument(s): | Jobin Yvon Ultima Inductively Coupled Plasma Spectrometer |
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Ammonia Phenolate Method
ammonia/ammonium
| | Instrument(s): | Lachat QuikChem 8500 |
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Cadmium column reduction
Nitrate
| | Instrument(s): | Lachat QuikChem 8500 |
| | Description: |
Ortho-phosphate
Dissolved reactive phosphate (ortho-phosphate)
| | Instrument(s): | Lachat QuikChem 8500 |
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