Abstract Detail



Ecology

Sebesta, Nicole [1], Richards, Jennifer [2], Taylor, Jonathan [3].

The effect of prescribed fire on mortality and regrowth of Lygodium microphyllum in southern Florida, USA.

The Old World Climbing fern, Lygodium microphyllum, has invaded a variety of habitats in southern Florida, USA, including Everglades National Park (ENP), and this invasive exotic continues to expand its range.  Lygodium microphyllum produces thick rachis mats that shade out native understory vegetation, inhibit native plant recruitment, impede animal movement, and alter fire behavior.  Extensive infestations may alter hydrology and inhibit critical ecosystem functions, including water filtration and aquifer replenishment.  In addition to chemical and biological control, ENP uses prescribed fire to manage Lygodium infestations, although the effectiveness of fire has not been documented in the field.  Greenhouse experiments monitoring L. microphyllum mortality and regrowth after a single controlled burn indicated that small plants suffer higher mortality than larger plants, and burned plants of all sizes showed reduced growth for > 1 year post-burn, as compared to clipped or control plants. To determine whether this pattern extends to heterogeneous field conditions, we monitored mortality and re-growth of individual plants after a prescribed burn in ENP.  In January 2017 we selected 210 L. microphyllum plants in coastal southern ENP; plants were distributed spatially and among three cover classes (120 small plants [each occupying < 1/16 m2], 60 medium [between 1/16 and ¼ m2], and 30 large plants [> ¼ m2]).  For each plant we documented height, extent (for large size class only), reproductive status, and biocontrol presence.  For small, medium, and large plants, respectively, average height was 66 ± 26, 92 ± 35, and 168 ± 55 cm; extent for large plants was 1.8 ± 1.5 m2, and the percent of plants sporulating was 10, 58, and 96%.  One biocontrol, a leaf-galling mite (Floracarus perrepae), was found on 80% of the plants and was present in all class sizes.
ENP burned the experimental area immediately following the initial survey, and three months post-burn, we resurveyed the plants to document mortality and regrowth. As in the greenhouse experiment, smaller plants suffered greater mortality: 80% of small, 52% of medium and 20% of large plants died. New growth on surviving plants reached average heights of 23 ± 12, 29 ± 11, and 47 ± 17 cm and large plant extent of 0.53 ± 0.4 m2. No plants were sporulating, and no biocontrol was present. Additional surveys monitored survivor re-growth and biocontrol re-establishment over two years.


1 - Florida International University, Department Of Biological Sciences, 11200 SW 8th Street, Miami, United States, 33199, USA
2 - Florida International University, Department Of Biological Sciences, Miami, FL, 33199, United States
3 - Everglages National Park, Restoration Program, 40001 State Road 9336, Homestead, FL , 33034 , USA

Keywords:
Fire
lygodium microphyllum
regrowth
mortality
invasive plants
biological control
weed management.

Presentation Type: Oral Paper
Number: 0009
Abstract ID:564
Candidate for Awards:None


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