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Harvard Forest Data Archive


Effect of Prey Availability on Sarracenia Purpurea Stoichiometry at Belvidere Bog, Vermont 2002

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  • Lead: Aaron Ellison, Nicholas Gotelli
  • Investigators: Amy Wakefield, Sarah Wittman
  • Contact: Information Manager
  • Start date: 2002
  • End date: 2002
  • Status: complete
  • Location: Belvidere Bog (Belvidere VT)
  • Latitude: +44.751152 degrees
  • Longitude: -72.657805 degrees
  • Elevation: 398 meter
  • Datum: WGS84
  • Taxa: Sarracenia purpurea (northern pitcher plant)
  • Release date: 2023
  • Language: English
  • EML file: knb-lter-hfr.328.3
  • DOI: digital object identifier
  • EDI: data package
  • DataONE: data package
  • Related links:
  • Study type: short-term measurement
  • Research topic: physiological ecology, population dynamics and species interactions
  • LTER core area: mineral cycling, organic matter movement, primary production
  • Keywords: carnivorous plants, leaves, nitrogen, nutrients, phosphorus, photosynthesis
  • Abstract:

    The carnivorous pitcher plant Sarracenia purpurea receives nutrients from both captured prey and atmospheric deposition, making it a good subject for the study of ecological stoichiometry and nutrient limitation. We added prey in a manipulative field experiment and measured nutrient accumulation in pitcher-plant tissue and pitcher liquid, as well as changes in plant morphology, growth, and photosynthetic rate. Prey addition had no effect on traditional measures of nutrient limitation (leaf morphology, growth, or photosynthetic rate). However, stoichiometric measures of nutrient limitation were affected, as the concentration of both N and P in the leaf tissue increased with the addition of prey. Pitcher fluid pH and nitrate concentration did not vary among treatments, although dissolved oxygen levels decreased and ammonia levels increased with prey addition. Ratios of N:P, N:K, and K:P in pitcher-plant tissues suggest that prey additions shifted these carnivorous plants from P limitation under ambient conditions to N limitation with the addition of prey.

  • Methods:

    Prey additions

    In May 2002 we haphazardly chose 200 nonflowering adult plants (rosettes ≥10 cm) in the open area of the bog. A distance of at least 50 cm separated all experimental plants. Each plant was randomly assigned to one of eight treatment levels (n = 25 plants per treatment), corresponding to 0-7 frozen houseflies (mean dry mass = 1 mg; 103 mg N/g; 7.6 mg P/g; 9.2 mg K/g; 1.7 mg Ca/g; 1.4 mg Mg/g) fed twice weekly to each pitcher throughout the summer. Flies were added only to pitchers produced during the 2002 growing season; prey addition began when the first new pitchers were produced (24 June 2002) and continued until 12 September 2002. We added distilled water as necessary to maintain pitcher fluid at half of the leaf volume (5–10 mL). Pitchers on each plant were numbered sequentially in order of opening date (Leaf I, Leaf II, Leaf III, etc.) and each leaf was fed until they were harvested for analysis.

    Field sample collection and processing

    At approximately two-week intervals (10 and 29 July, 13 August, 2 and 15 September), all fed pitchers were harvested from each of five randomly chosen plants from each treatment group. Immediately before each harvest, dissolved oxygen content of the pitcher fluid (milligrams per liter and percentage saturation) of each leaf designated for that harvest was measured in situ using a YSI-58 dissolved oxygen meter (YSI instruments, Yellow Springs, Ohio, USA). Each pitcher was then cut off at the base; pitcher fluid was poured into sterile plastic tubes (50-mL centrifuge tubes) for subsequent analysis and the pitcher itself placed into a Ziploc plastic bag. All harvested material was kept cool and returned to the laboratory at the University of Vermont for processing within 4 h. In the laboratory, the pitcher fluid was filtered using a Millipore Sterifil Aseptic system. The pH of the filtrate was measured with an Orion Model 290A portable pH/ISE meter, and nitrogen (both NO3-N and NH4-N) and phosphorus (PO4-P) concentrations were determined spectrophotometrically using standard methods.

    Morphometrics and tissue nutrient content

    The length, mouth diameter, and maximum width (±1 mm) of each harvested pitcher or phyllode was measured, along with the width of its wing (keel). All leaves were dried at 70 °C for 3–5 days, and individually weighed and ground for nutrient analysis at the University of Vermont Agricultural and Environmental Testing Laboratory (Burlington, Vermont, USA).


    On 15 August 2002 we measured maximum photosynthetic rates of the Leaf I on two randomly selected plants from each treatment level. These plants were all harvested at the fourth harvest (2 September). Photosynthesis measurements were made in full sun, between 09:00 and 14:00 hours, using a LI-COR 6200 photosynthesis system and custom built 4-L chamber. During all measurements, ambient solar radiation exceeded the saturating photosynthetic photon flux density of Sarracenia (PPFD > 800 mmol·m-2·s-1).

  • Organization: Harvard Forest. 324 North Main Street, Petersham, MA 01366, USA. Phone (978) 724-3302. Fax (978) 724-3595.

  • Project: The Harvard Forest Long-Term Ecological Research (LTER) program examines ecological dynamics in the New England region resulting from natural disturbances, environmental change, and human impacts. (ROR).

  • Funding: National Science Foundation LTER grants: DEB-8811764, DEB-9411975, DEB-0080592, DEB-0620443, DEB-1237491, DEB-1832210.

  • Use: This dataset is released to the public under Creative Commons CC0 1.0 (No Rights Reserved). Please keep the dataset creators informed of any plans to use the dataset. Consultation with the original investigators is strongly encouraged. Publications and data products that make use of the dataset should include proper acknowledgement.

  • License: Creative Commons Zero v1.0 Universal (CC0-1.0)

  • Citation: Ellison A, Gotelli N. 2023. Effect of Prey Availability on Sarracenia Purpurea Stoichiometry at Belvidere Bog, Vermont 2002. Harvard Forest Data Archive: HF328 (v.3). Environmental Data Initiative:

Detailed Metadata

hf328-01: prey additions

  1. plantnum: individual plant number
  2. fliesperwk: number of flies added each week (unit: number / missing value: NA)
  3. harvest: harvest date
    • 1: 10 July 2002
    • 2: 29 July 2002
    • 3: 13 August 2002
    • 4: 2 September 2002
    • 5: 15 September 2002
  4. dissolved oxygen concentration (unit: milligramsPerLiter / missing value: NA)
  5. do.pct: dissolved oxygen (percent saturation) (unit: dimensionless / missing value: NA)
  6. halfvol: half of the total volume of the pitcher (unit: milliliter / missing value: NA)
  7. lflen: leaf length, measured from the base of the pitcher to the top of the hood (unit: millimeter / missing value: NA)
  8. lfwid: maximum leaf width, measured from the midrib and including the keel (unit: millimeter / missing value: NA)
  9. keelwid: maximum width of the keel, from its outer edge to the edge of the pitcher tube (unit: millimeter / missing value: NA)
  10. diam1: larger diameter of the elliptical pitcher mouth (unit: millimeter / missing value: NA)
  11. diam2: smaller diameter of the elliptical pitcher mouth, measured perpendicular to diam1 (unit: millimeter / missing value: NA)
  12. leafarea: leaf area of the flattened pitcher (unit: squareCentimeters / missing value: NA)
  13. leafmass: dry mass of the pitcher (unit: gram / missing value: NA)
  14. ph: pH of the pitcher fluid (unit: dimensionless / missing value: NA)
  15. no3: concentration of nitrate-N in the pitcher fluid (unit: milligramsPerLiter / missing value: NA)
  16. nh4: concentration of ammonium-N in the pitcher fluid (unit: milligramsPerLiter / missing value: NA)
  17. po4: concentration of phosphate-P in the pitcher fluid (unit: milligramsPerLiter / missing value: NA)
  18. pct.n: concentration of nitrogen in dried leaf tissue (percent) (unit: dimensionless / missing value: NA)
  19. ca.ppm: concentration of calcium in dried leaf tissue (ppm) (unit: dimensionless / missing value: NA)
  20. p.ppm: concentration of total phosphorus in dried leaf tissue (ppm) (unit: dimensionless / missing value: NA)
  21. k.ppm: concentration of potassium in dried leaf tissue (ppm) (unit: dimensionless / missing value: NA)
  22. mg.ppm: concentration of magnesium in dried leaf tissue (ppm) (unit: dimensionless / missing value: NA)