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Abstract Detail



Ecology

Koontz, Stephanie [1], Menges, Eric [1].

Demography of Chrysopsis highlandsensis: 16 years of data, trends, experiments, and discoveries.

Background/Questions/Methods Described in 2002, Chrysopsis highlandsensis (Asteraceae) is a state-listed herb endemic to the Lake Wales Ridge in central Florida. Data collected from 1999 - 2015 provide information on individual vital rates but also larger population trends. We collected demographic data on marked individuals at three protected sites and across two habitat types (Florida scrub and human-made sandy roads). Survival and recruitment data were collected quarterly in permanent transects in March, June and September, with more detailed measures of growth and fecundity collected in December when plants were reproductive. We counted the number of reproductive individuals in rangewide surveys in 2005, 2010 and 2015 on public and private lands across multiple habitat types, with various land management practices and histories. Our goal was to describe demographic trends of C. highlandsensis across multiple spatial scales, various habitat types and in response to land management. Results/Conclusion Seedlings recruit year-round, with most recruits found in March (59.2% of all recruits) and along sandy roadsides (84.4%). Most seedlings do not survive their first year (46.5% survival) and 8.5% reach reproductive maturity. Mean age at first flowering is 4 years (range 2-12) with most plants dying immediately post-flowering (95.4% mortality). Of reproductive plants, 88% flowered once, 10% twice and 2% three or more times, indicating C. highlandsensis is not strictly semelparous. Significantly more plants flowered in scrub habitats (30.8%) compared to sandy roadsides (14.8%; ? = 108.5, df =1, p < 0.001). Reproductive plants had a median of 35 flowering heads (range 5-525), with 78 achenes (range 3 - 119) per flowering head, with 67.0% intact achenes. Germination trials of intact achenes reached 26.5%. Rangewide censuses showed some populations in decline while others remained stable or increased. Plants were predominantly found in scrubby flatwoods (72.1%), especially within the vicinity of old trails and sandy roads (93.6%), suggesting this species prefers open microsites maintained by disturbance. Unlike other scrub endemics, however, the post-fire environment does not favor this species, with few plants resprouting and low seedling recruitment. The combination of fine scale demographic data and larger rangewide census data provide vital information on the life history strategy of this short-lived, perennial herb and population trends within its range. Management practices must include maintaining open scrub habitat at intervals that allow plants to complete their lifecycle. Disturbance from patchy fires may spare some individuals from burning while opening microsites for seedling recruitment.


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1 - Archbold Biological Station, 123 Main Drive, Venus, Fl, 33960, United States

Keywords:
demography
new species
disturbance
fire
Conservation.

Presentation Type: Oral Paper
Session: 31, Ecology Section - Population Biology
Location: 106/Mayo Civic Center
Date: Tuesday, July 24th, 2018
Time: 3:00 PM
Number: 31007
Abstract ID:216
Candidate for Awards:None


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