Microhabitat of Critically Endangered Lupinus aridorum (Fabaceae) at Wild and Introduced Locations in Florida Scrub* Rare Plant Conservation Program Juliet Rynear, Rare Plant Specialist Dr. Matthew Richardson Photo by Cindy Campbell *Richardson, Rynear, Peterson. 2014. Microhabitat of Critically Endangered Lupinus aridorum (Fabaceae) at Wild and Introduced Locations in Florida Scrub. Plant Ecol (2014) 215:399–410. Research since 1986 ~ Lupinus aridorum • Propagation protocols • Testing fungicides, insecticides, larvicides, fertilization • Species biology – Seed dormancy – Population genetics – Symbiotic interactions with soil organisms – Root exudates • Introduction protocols • Monitoring protocols for introduced populations Photo by Bill Parken Scrub Lupine - Lupinus aridorum McFarlin ex Beckner (Fabaceae) Photo by Brad Kolhoff Florida endemic Scrub community Short-lived perennial Unifoliolate Leaves appear silver covered in fine hairs Long taproot Mycorrhizal & rhizobial associations Long lived seed bank Historical Range Lupinus aridorum Population Losses Year Number of Wild Populations Prior to 2002 45 2002 22 2009 8 2012 10 2014 9 Habitat loss is the primary threat to Scrub Lupine, followed by canopy closure due to fire suppression Why a Microhabitat Study? Population Introductions Year of introduction March 2014 total # plants Lake Blue Scrub 2008 1,145 Mackay Gardens & Lakeside Preserve 2010 193 Bill Frederick Park 2010 63 Tibet-Butler Preserve 2008 4 Wekiwa Springs State Park 2010 0 Oakland Nature Preserve 2011 0 Introduction location Lake Blue Scrub Mackay Gardens Mackay Gardens Bill Frederick Park – introduction site Bill Frederick – introduction site – year 3 Microhabitat Study Goals 1. Determine whether L. aridorum has multiple cytotypes because this can influence its spatial distribution 2. Measure how microhabitat characteristics at locations that support L. aridorum plants vary from random locations within the same population 3. Measure whether microhabitat characteristics differ between locations supporting wild or introduced populations, to provide information about the realized and fundamental niche. Methodology Populations studied: 1. Lake McLeod (wild) 2. Shadow Bay Park (wild) 3. Bill Frederick Park (wild) 4. Bill Frederick Park (introduced) 5. Lake Blue Scrub (introduced) 6. Mackay Gardens (introduced) Lake McLeod Left to right: Lois Smith, Mitch Sheets, and Jerry Burns Shadow Bay Park Bill Frederick Park - Old Seedbank Area Following Site Clearing in 2010 Methodology 1. To determine the cytotypic composition • 3 wild populations were sampled • 10 individuals chosen from 3 microhabitats at each site (N = 30) • Fresh leaves collected • Cytotyped using flow cytometry at Iowa State University Methodology 2. Measured microhabitat characteristics at each population • • • • Location = 2 meter2 quadrats 20 quadrats centered on L. aridorum plants 20 quadrats at random locations Environmental variables were measured Environmental variables measured: 1. Distance to the nearest overstory tree and species id; 2. Distance to the nearest woody shrub and species id; 3. Soil moisture; 4. Canopy density; 5. Number of woody stems within the 2 m2 quadrat; 6. Species richness within the quadrat (i.e., number of plant species); 7. Maximum height of the understory vegetation within the quadrat; 8. Percentage of ground cover types within the quadrat • Detritus (6 categories, including bare ground); • Grasses; • Herbaceous plants (non-grasses); • Woody plants. Data Statistically analyzed by Dr. Matthew Richardson Photo of Dr. Richardson courtesy of Photobucket 1. For wild populations, we calculated the percentage of times four categories of overstory trees were the nearest tree to L. aridorum plants and random quadrats: 1) P. borbonia; 2) Pinus spp. [predominately Pinus clausa (3) Quercus spp. (predominately Q. geminata Small); or 4) other species of trees. 2. We calculated the percentage of times five categories of shrubs were closest to wild and random locations: 1) Ceratiola ericoides; 2) Garberia heterophylla; 3) Quercus spp. (predominately Q. geminata); 4) Serenoa repens; or 5) other species of shrubs. 3. We calculated the percentage of times four categories of herbaceous plants were the most abundant ground cover within the 2 m2 quadrat at wild and random locations: 1) Cladonia leporina; 2) grass spp.; 3) Polygonella polygama; and 4) other species. 4. We calculated the percentage of times each of the six categories of detritus was the dominant type at wild and random locations. For introduced populations, calculations were similar • However, differences in the most prevalent species at introduction sites, which included many non-native species, resulted in the addition of a non-native category Results 1. All L. aridorum samples were diploid 2. At wild populations, the data showed that L. aridorum plants were more likely to be located near : Persea borbonia Serenoa repens Additionally, the wild quadrats were more likely to contain a mix of detritus than in the random quadrats The most important predictor variables between wild and random locations, were: The distance to the nearest shrub The proportion of bare ground At wild populations, L. aridorum plants were a mean distance of 195 cm from shrubs while random quadrats were a mean distance of 401 cm from shrubs In wild quadrats, 62% of the ground was bare while in random quadrats 51% of the ground was bare. Moderately important predictor variables were the distance to the nearest tree and soil moisture. L. aridorum plants at wild populations were 37% closer to trees than were random quadrats. Soil moisture was lower near L. aridorum than at random quadrats. Bill Frederick Park – wild population 3. Comparing microhabitat between introduced populations, wild populations, and random locations, the data highlighted a number of characteristics that differed significantly. The species of the nearest tree; The species of the nearest shrub; Ground cover; Detritus. Persea borbonia and Pinus species more likely to occur near L. aridorum plants at wild populations than at introduced populations. Sideroxylon tenax occurred more often near L. aridorum plants at introduced populations and near random quadrats than near plants at wild populations. The ground cover plant Cladonia leporina was much more likely to occur near wild plants than either introduced plants or random quadrats; whereas, Paronychia chartacea spp. chartacea and non-native plant species were more likely found near introduced plants and random quadrats. In summary, The realized niche is narrower than the fundamental niche. Community of species (trees, shrubs, groundcover) is important. L. aridorum appears to grow in association with some canopy cover and detritus, in contrast to a number of scrub community specialists (e.g., QuintanaAscencio and Morales-Hernandez 1997; Menges et al. 2006) Bill Frederick Park – wild population Kerina Kerina Parkside Tract 2 ~ Scrub Community Rescue Thank you! Volunteers, project partners, and funding sources: Private landowners Florida Native Plant Society Ridge Rangers, Sierra Club, Master Naturalists Florida Fish & Wildlife Conservation Commission U.S. Fish & Wildlife Service Florida Dept. of Agriculture and Consumer Services, DPI The Nature Conservancy Orange County, City of Orlando, and City of Lake Alfred
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