Disturbance

SDR01 Intra-clonal stem demography of Cornus drummondii in response to fire and browsing at Konza Prairie

Abstract: 

Intra-clonal stem density, natality, mortality, flowering and relative growth rate within discrete Cornus drummondii shrubs in response to fire frequency (4- vs 20-yr burn intervals) and simulated browsing. Tagged stems within individual shrubs were tracked and measured at the beginning and end of each growing season in 2018 and 2019 to assess the interactions of fire and browsing on stem demography.

Data set ID: 

155

Core Areas: 

Short name: 

SDR01

Data sources: 

Methods: 

Data were collected in the lowlands of watersheds 4B and 20C in 2018 and 2019 at Konza Prairie Biological Station. In 2015, 40 discrete Cornus drummondii shrub clones were chosen in the lowlands of watersheds with a 4-yr and 20-yr burn frequency. Half of the shrubs in each burn frequency were randomly selected for a simulated browsing treatment. From 2015-2019, browsing was simulated by stripping 50% of current year shoot growth by hand from each stem once a month from May-September. See O’Connor et al. 2020 and dataset FWE01 for more detail. We used this browsing experiment to assess the effects of fire and simulated browsing on stem density, growth, reproduction, and demography within individual shrubs.

We established 0.25 m wide transects through the longest axis of each shrub. In May 2018, we tagged each stem, including all stems originating from basal buds at the soil surface and rhizomatous buds, within each transect using insulated copper wire around the shoot base. Stems were counted again in August and the number of dead (with tag) and new stems (no tag) were recorded. Tagging and counting were repeated in April and September of 2019.

Data Collection:

  • Stem densities – number of live stems within the transect divided by the area (m2) of the transect.
  • Flower production – number of flowering stems within each transect during peak flowering. The proportion of flowering stems within each transect can be calculated as the number of flowering stems divided by the total number of stems within the transect.
  • Recruitment – number of new stems within each transect at the end of the growing season. Proportion of new stems can be calculated as the number of new stems at the end of the season divided by the total number of stems at the end of the season.
  • Mortality – number of tagged stems dead at the end of the growing season. Proportion of dead stems can be calculated as the number of dead stems with tags at the end of the season divided by the number of live stems at the beginning of the season.
  • Flowering effort – number of inflorescence clusters on 5 stems on the periphery and 5 stems in the center of each shrub.
  • Stem height – height measured to the last leaf-bearing node on the tallest shoot axis of 5 stems on the periphery and 5 stems in the center of each shrub. Height was measured in June and August in 2018 and May and August in 2019.
  • Stem basal diameter – basal diameter of 5 stems on the periphery and 5 stems in the center of each shrub. Basal diameter was measured in June and August in 2018 and May and August in 2019.
  • Shrub area – calculated using an ellipse area equation by measuring the length of the longest axis of each shrub and perpendicular width at the end of each growing season.
  • Leaf area – leaf area of 4 randomly selected leaves from each shrub was measured using the LEAFSCAN smartphone application (leafscan.com).

References:
1. O’Connor RC, Taylor JH, Nippert JB (2020) Browsing and fire decreases dominance of a resprouting shrub in woody encroached grassland. Ecology 0:1-11 doi: 10.1002/ecy.2935
2. Nippert, J., O'connor, R.  2019.  FWE01 Effects of browsing and fire on woody encroachment at Konza Prairie. Environmental Data Initiative. http://dx.doi.org/10.6073/pasta/7ec1d77684c30eb707468f72db101bb0.

For additional metadata information see: http://lter.konza.ksu.edu/sites/default/files/DC.pdf
For additional methods information see: http://lter.konza.ksu.edu/sites/default/files/MM.pdf

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