Archbold biological station

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Archbold biological station

• The Role of Fire in Shaping and Maintaining Plant
  Communities in Florida Scrub

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Archbold Biological Station

• R. Archbold fortune from Standard Oil
• Aviator and explorer
• Expeditions to New Guinea and Australia
• Established research station in 1941

archbold-station.org
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Archbold Biological Station

• Southern portion of Lake Wales Ridge
• Preserve 5,193 acres
• Additional 3,648 acres adjacent

archbold-station.org
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Florida Scrub Habitat

• Unique ecosystem
• Occurs on relic sand dunes
• Inland Ancient Islands
• Coastal
• Vegetation shaped by
• Climate
• Soil
• Fire

Abrahamson 1984
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Ancient Islands

• 2 million years ago
• Higher sea level Lake Wales Ridge exposed
• Shoreline and dunes
• Isolated community
• Biodiversity
• 20 endemic plants, also endemic animal species
• T E species at state and federal levels

archbold-station.org
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Florida Scrub Habitat
http//ibc.lynxeds.com
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Threats to Florida Scrub Habitat
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Scrubby Flatwoods
Rosemary Scrub
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Rosemary Scrub

• High elevation 40 50 m
• Well drained sandy soil
• Very low nutrients
• Fire return interval 20-60 yr
• Vegetation
• Dominated by Florida Rosemary
• Herbaceous species associated with open space
• Obligate seeders majority of species

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Scrubby Flatwoods

• Elevation 38 46 m
• Well drained sandy soils
• Low nutrients but higher
  productivity
• Fire return interval 5-20 yr
• Vegetation
• Dominated by oaks and shrubs
• Majority of species resprouters

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Fire and Habitat

• Rosemary scrub
• Long fire return interval compared to Florida
  communities
• High intensity
• Stand replacing

• Scrubby flatwoods
• Frequent fire
• Can be high intensity
• Rapid recovery

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Role of Fire

• Life history strategies of scrub plants
• Competition and fire
• Allelopathy in scrub habitat
• Importance of fire to gaps

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Life History Strategies and Fire

• Menges and Kohfeldt 1995
• Count and ID species - areas with known TSF
• Rosemary scrub and scrubby flatwoods
• Assigned to guilds
• Resprouters
• Resprouters and seeders
• Obligate seeders
• Resprouters and clonal spreaders

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• ROSEMARY SCRUB

• SCRUBBY FLATWOODS

• Dominant spp - seed bank
• 50 of habitat specialists obligate seeders
• Open space decreases with increasing TSF gaps
  remain long term
• 10 of obligate seeders decrease in abundance
  with increasing TSF

• Dominant spp - resprout post fire
• 61 of habitat specialists resprout
• Open space decreases rapidly post fire
• 29 of obligate seeders decrease in abundance
  with increasing TSF

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Life History Strategies and Fire

• Decrease open space with increase in TSF
• Rosemary scrub favors seed sprouting and scrubby
  flatwoods favors resprouting
• Different vegetation structure
  difference in fire return interval
  reinforcement of life history strategies
• Also Givens et al. 1984, Abrahamson 1984 Loss
  of herbs and open space, increase in litter,
  increase in shrubs with longer TSF

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Competition and Fire

• Quintana-Ascencio and Menges 2000
• Transplanted herbaceous species
• Proximity to shrubs
• Recently burned and long unburned
• Survival, biomass, and reproductive output
• Conducted in rosemary scrub patches

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Competition and Fire

• Proximity to shrubs
• No effect on survival
• Reduced biomass
• Time since fire
• 2 of 3 species higher survival in recently burned
  patches at one site
• Indirect effect of fire
• Reduce competition from shrubs

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Allelopathy

• Hunter and Menges 2002
• Effects of Florida rosemary leaf and litter
  leachate on seed germination
• Distribution of Florida rosemary litter and roots
  

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Conclusions

• Florida rosemary leachate reduced seed
  germination
• With longer TSF increase Florida rosemary roots
• Skeletons of Florida rosemary as a lasting
  source of allelopathic chemicals
• Similarly - presence of lichen mats reduces seed
  germination of herbaceous species (Hawkes and
  Menges 2003)

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Gap Size and Fire

• Menges and Hawkes 1998
• Menges et al. 2008
• Synthesis of earlier work
• Census of 805 gaps
• Gap features
• Species occurrence and diversity
• Subset - detailed vegetation cover data

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Gap Size and Fire

• Effects of gap size gt effects of TSF
• Decrease in species richness and herb diversity
  with increasing TSF
• Changes in fire regime of a community type could
  alter community
• Increase frequency in rosemary scrub lose
  seeders
• Decrease frequency in scrubby flatwoods
  increase woody species

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• Fire behavior measurements
• Most studies use TSF as a variable
• Fires assumed to be equal
• What about herbivores?
• Belowground competition?
• Low moisture low nutrient system
• Competition for resources belowground may be more
  intense than aboveground competition

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Conclusions

• Community of highly adapted species
• Soil, fire, competition
• Fire important for maintaining each community
  type
• Fire return interval
• Fire intensity

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• Works Cited
• Abrahamson, W.G. 1984. Post-fire recovery of
  Florida Lake Wales Ridge vegetation. American
  Journal of Botany 719-21.
• Abrahamson, W.G., A. F. Johnson, J. N. Layne, and
  P.A. Peroni. 1984. Vegetation of the Archbold
  Biological Station, Florida An example of the
  southern Lake Wales Ridge. Florida Scientist
  47209-250
• Givens, K.T., J. N. Layne, W. G. Abrahamson, S.C.
  White-Schuler. 1984. Structural changes and
  successional relationships of fire Florida Lake
  Wales Ridge plant communities. Bulletin of the
  Torrey Botanical Club 1118-18.
• Hawkes, C. V. and E. S. Menges. 2003. Effects of
  lichens on seedling emergence in a xeric Florida
  shrubland. Southeastern Naturalist 2223-234.
• Hunter, M.E. and E.S. Menges. 2002. Allelopathic
  effects and root distribution of Ceratiola
  ericoides (Empetraceae) on seven roemary scrub
  species. American Journal of Botany 891113-1118.

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• Menges, E. S. and N. Kohfeldt. 1995. Life history
  strategies of Florida scrub plants in relation to
  fire. Bulletin of the Torrey Botanical Club
  122282-297.
• Menges, E. S. and C.V. Hawkes. 1998. Interactive
  effects of fire and microhabitat on plants of
  Florida scrub. Ecological Applications 8935-946.
• Menges, E.S., A. Craddock, J. Salo, R. Zinthefer,
  W. Carl. 2008. Gap ecology in Florida scrub
  Species occurrence, diversity and gap properties.
  Journal of Vegetation Science 19 503-514.
• Quintana-Ascencio, P.F. and E.S. Menges. 2000.
  Competative abilities of three narroly endemic
  plant species in experimental neighborhoods along
  a fire gradient. American Journal of Botany
  87690-699.