Tuesday evening, 7PM -- Posters

8. Boughton, Elizabeth A.¹, Pedro F. Quintana-Ascencio¹, Eric S. Menges², and Raoul K. Boughton³ . ¹University of Central Florida, ²Archbold Biological Station, ³University of Memphis. Association of relative elevation and fire to ecotones in an upland Florida landscape.

 Although ecotones often arise predictably across the landscape, identifying their exact location requires objective quantitative methods. We objectively identified ecotones in upland Florida shrublands using a split moving windows boundary analysis (SMW) along 20 randomly chosen transects traversing identical elevation gradients, stratified by time-since-fire (TSF) categories.  Significant peaks in SMW graphs defined three plant communities similar to previously described vegetation associations, an additional new plant community and two extended ecotonal zones. A non-metric multidimensional scaling (NMDS) ordination was used to determine that plant communities defined by SMW were similar in vegetation cover.  We found that relative elevation (not absolute) is a primary factor controlling the distribution of plant communities in upland Florida shrublands. Ecotones in shrublands 30+ years TSF become less sharp or blurred, indicating that plant communities with greater TSF are more alike.

9. Carrel, James E. University of Missouri. Responses of rare burrowing wolf spiders to fire in Florida scrub.

 Abstract not available

10. Quintana-Ascencio, Pedro F.¹ and Eric S. Menges² . ¹University of Central Florida, ²Archbold Biological Station. A spatially explicit individually based model of Florida rosemary and scrub hypericum population dynamics.

We developed an individual-based simulation model summarizing spatial patterns of two Florida scrub plants: scrub hypericum (Hypericum cumulicola), an herbaceous species virtually restricted to gaps within Florida rosemary scrub, and Florida rosemary (Ceratiola ericoides), the dominant shrub species in the community. Our model predicts post-fire population dynamics using: (1) survival, growth, and recruitment estimates of scrub hypericum based on plant location, plant size, distance to nearest Florida rosemary, and conspecific density; (2) Florida rosemary growth based on plant size and distance to conspecific neighbors; a beta dispersal function of scrub hypericum distribution obtained from transplant experiments; and (4) an experimental evaluation of scrub hypericum seed and seedling dynamics. Model predictions were verified using comparisons to observed scrub hypericum data. We generally did not find differences between predictions and observations although models unpredicted variation. Our simulations were successful in projecting the patchy distribution of scrub hypericum among and within gaps and the effects of rosemary densities in suppressing scrub hypericum. Spatial models incorporating rosemary inhibition can improve non-spatial models based on time-since-fire.

11. Ulrey, Wade A¹, Joseph M. Guthrie¹, Mason Smoak², and David S. Maehr¹. ¹Department of Forestry, University of Kentucky, ²Smoak Groves, Inc., Lake Placid, FL. Black bear ecology in south-central Florida: A progress report.

The Florida black bear (Ursus americanus floridanus) once occupied most of Florida, but persists only in isolated populations. In Highlands and Glades Counties, a small bear population inhabits a landscape dominated by agriculture. All other bears in the state live in areas with extensive public lands and large blocks of forest. We are studying Highlands County black bears to determine how they survive in a patchy, human-altered environment.  Bears are captured using spring-activated snares. All captured bears undergo a series of measurements, physiological evaluations, and tissue sampling. They are then fitted with either standard VHF collars or GPS collars which automatically obtain and store locations.  Collared bears are tracked weekly from aircraft. Locations are plotted on aerial photographs, and recorded as Universal Transverse Mercator (UTM) coordinates. Data from in-collar “tip switches” which record the animal’s head movements are used to assess diel activity patterns. Preliminary analysis suggests that these bears are crepuscular, that males have much larger home ranges than females, and that the population has a healthy sex ratio and demographic structure. Also, habitat use appears to vary seasonally. While flatwoods and bay swamps have been frequented in all seasons sampled, bears show increased use of scrub in late summer and early fall, and oak and cabbage palm hammocks in late fall.

12. Weekley, Carl W. and Eric S. Menges. Archbold Biological Station. Experimental introduction of Ziziphus celata at the Lake Wales Ridge National Wildlife Refuge (Carter Creek).

Florida ziziphus (Ziziphus celata), the rarest and most imperiled Lake Wales Ridge endemic plant, is a self-incompatible and genetically depauperate clonal shrub occurring on only six sites. The nine remnant genotypes comprise only two cross-compatible mating types, the minimal number that a self-incompatible species can retain and still be sexually viable.  However, progeny from these two mating types include a third mating type. The enhanced genetic diversity of F1 propagules provides the material for implementation of the US Fish and Wildlife Service’s Recovery Plan, which requires the establishment of sexually viable populations in appropriate habitat on publicly protected land.

In 2002, we transplanted 144 potted plants and planted 1728 seeds at the Lake Wales Ridge National Wildlife Refuge (Carter Creek). The introduction, embedded in a larger project investigating the restoration dynamics of a long-unburned sandhill, was designed as an experiment to address three questions central to the recovery program: (1) is translocation of potted plants more effective than sowing seeds in establishing a new population? (2) what microhabitat conditions best promote the survival of introduced transplants and the germination of seeds? (3) does the demographic performance of introduced propagules vary by parental genotype? Two years post-introduction, 84.7% of the Florida ziziphus transplants (122/144) are still alive, but only 3.6% of planted seeds (62/1728) have germinated. While transplant survival was significantly higher in unburned and partially burned sites than in more intensely burned sites, it was unaffected by such microhabitat conditions as vegetative and litter cover, or by parental genotype.

8:30-9:00
14. Bowman, Reed. Archbold Biological Station. Overview of research in the Avian Ecology Lab: Variation in demography and life history strategies of birds across environmental gradients.

For the past 35 years, Glen Woolfenden and his colleagues and students have studied the demography and life history of Florida scrub-jays in native, fire maintained oak scrub at Archbold Biological Station. Nearly 20 years ago the study was expanded to the southern portion of Archbold to provide an opportunity for manipulative experiments. Today, we study scrub-jays in a variety of spatial and environmental contexts including large contiguous patches (Archbold), scrub perforated by suburban development (Placid Lake Estates) and fragmented scrub patches in a heterogenous, but largely natural landscape (Avon Park Air Force Range). In total, we monitor the daily lives of over 200 groups of scrub-jays. I will discuss some of our projects that investigate the impacts of environmental variation on the selected suite of behavioral, physiological, and demographic traits of scrub-jays that have uniquely adapted this species to the ecological processes and characteristics of xeric oak scrub communities. In addition, we conduct research on sources of demographic variation and habitat requirements on two other species: the red-cockaded woodpecker and the Florida grasshopper sparrow. I will briefly review some of the work completed and on-going on these species and mention other projects in the lab.

9:00-9:30
15. Boyle, Owen D. University of Wisconsin at Madison. Metapopulation ecology and genetics of the Florida scrub endemic Polygonella basiramia.

Polygonella basiramia is a rare plant endemic to the naturally patchy, fire-driven Florida scrub ecosystem. I analyzed long-term demographic data using metapopulation approaches to determine how habitat patch properties affect patch occupancy and turnover. P. basiramia inhabits white sand gaps in the rosemary shrub community that itself occurs patchily, allowing me to explicitly consider the scale of metapopulation dynamics. From 1999 to 2002, turnover among 1,210 gaps was 8%/year and dominated by local extinctions. Logistic regression shows that the incidence of P. basiramia within gaps increases in larger, less isolated gaps.  The probability of local extinction decreases with increasing gap area. The probability that a vacant gap is colonized rises with gap area and proximity to other occupied gaps. Extinction and colonization of populations within 83 rosemary patch populations occurred more slowly (1%/year, 1989 - 1999) and responded less to habitat characteristics, as expected if large scale patterns integrate over smaller-scale dynamics. I also used Bayesian methods to estimate genetic diversity and strucure from 81 polymorphic AFLP markers at the small scale and 102 markers at the large scale.  Within-deme heterozygosity was moderate at both scales (Hs = 0.263) and was not correlated with deme age, patch area, or isolation. Population differentiation as measured by F_ST was low (small scale = 0.140, large scale = 0.046) and decreased with patch age. Patterns of gene flow and genetic structure are consistent with the rapid turnover dynamics observed in the field. Opportunistic roadside populations harbor genetic diversity similar to scrub populations.

9:30-10:00
16. Maehr, David S., University of Kentucky, and James N. Layne, Archbold Biological Station. The black bear in Highlands County: a 40-year historical perspective.

Abstract not available

10:00-10:30 break

10:30-11:00
17. Menges, Eric S. Archbold Biological Station. Pyrodemography, conservation, and restoration in Florida scrub plants.

Our research on pyrodemography combines synchronic chronosequences, diachronic long-term studies, experiments, and population viability analyses. This combination obviates weaknesses of individual approaches. We have applied these studies to many scrub plants, linking demographic mechanisms to population dynamics patterns. PVAs suggest fire (at different frequencies) is key to viability of several species, although some plants are relatively indifferent to fire regime. For Warea carteri, marked two-year cycles of abundance are endogenously driven by life history, dampened by stochastic variation, and triggered by fire. Life history traits of organisms in a habitat and their viability with respect to fire can be used to define evolutionarily relevant fire regimes that can be used to refine fire management. Habitat specialists and endemics should provide particularly relevant information. For example, PVAs of Dicerandra frutescens and Eryngium cuneifolium have reduced our estimates on the fire return intervals typical of oak-hickory and rosemary scrub, respectively. We are currently working on validation of a Polygonella PVA using independently collected data and searching for climate drivers to scrub plant demography. We will also nest metapopulation demography experiments within proposed experimental restoration in the newly-acquired Reserve, adjacent to the Station.

11:00-11:30
18. Carrel, James E. University of Missouri. Toward a natural history of endemic scrub spiders.

Abstract not available

11:30-12:00
19. Boughton, Raoul K.¹, Reed Bowman², and Stephen J. Schoech¹. ¹University of Memphis, ²Archbold Biological Station. Variation in immune response of  Florida scrub-jay (Aphelocoma coerulescens) nestlings in suburban and wildland populations.

Abstract not available

12:00-1:00 LUNCH ($6 CHARGE, SIGN UP IN MAIN OFFICE)

Wednesday afternoon, 12 January 2005
1:30-2:00
20. Turner, Will¹, David S. Wilcove¹, and Hilary M. Swain². ¹Princeton University, ²Archbold Biological Station. State of the scrub: Assessing progress and identifying future priorities for conservation of rare and endangered species on the Lake Wales Ridge.

Large numbers of narrow endemics and extensive habitat loss have resulted in the Lake Wales Ridge scrub harboring one of he highest concentrations of endangered species in the continental USA. To date, conservation efforts have acquired many remaining fragments of the LWR xeric uplands. However, thus far, little attempt has been made to assess systematically (i.e. LWR-wide and for all possible taxa) the extent to which the emerging reserve network protects remaining populations of rare and endangered species. The ability to measure progress in meeting conservation goals is essential when resources are limited and time is crucial. With participation from FNAI and all LWR managing agencies, we initiated a “State of the Scrub” project to fulfill this need.  Goals of this ongoing project include (1) synthesize existing data on the distribution of these species from various sources into a coherent database; (2) systematically assess contributions of past and planned LWR acquisition efforts toward protecting species; (3) identify potential species of local management priority for any LWR site or managing agency; and (4) determine which remaining sites would, if acquired, contribute most toward species protection. We developed a set of continuous, quantitative Protection Indices, based on 3 criteria used in the IUCN Red List, to measure the degree to which acquisition efforts reduce the threats to individual species. We are nearing completion of goals (1-3) and have begun work on (4). We here present current results toward each of these goals.

2:00-2:30
21. Weekley, Carl W.¹ and Mandy Brothers². ¹Archbold Biological Station, ²Indiana University. Failure of reproductive assurance in the self-compatible herb Polygala lewtonii.

In a species with both obligately-selfing (CL = cleistogamous) and open-pollinated (CH = chasmogamous) flowers with a putative mechanism guaranteeing delayed autonomous selfing, theory would predict high levels of reproductive assurance. Obligate selfing might be expected to purge deleterious alleles, although even species that routinely self can have high levels of inbreeding depression.  Delayed autogamy is always advantageous even if some inbreeding depression occurs, because it results in offspring—however inferior—that would not otherwise have been produced. We used pollinator-exclusion experiments to investigate the level of reproductive assurance in Polygala lewtonii, a perennial herb with both CH and CL flowers and a floral mechanism putatively ensuring selfing. We followed CH flower development in the field daily from bud-break to flower or fruit abscission and used microphotographs to evaluate the efficacy of the putative selfing mechanism.  We also conducted pollinator watches to assess the likelihood of pollinator limitation and performed regression analysis to determine the effect of flower location on fruit initiation and maturation.  We found that both fruit initiation and fruit set are significantly reduced in pollinators-excluded flowers. Investigation of floral development demonstrated that the mechanism putatively ensuring selfing is largely dysfunctional, leading to the erosion of reproductive assurance. Low insect visitation rates suggest that P. lewtonii may be pollinator-limited. In both pollinators-excluded and open-pollinated flowers, fruit initiation and fruit set were significantly lower in flowers located near the apex of the raceme than in flowers near the base, suggesting resource limitation as an additional cause of reproductive failure.

2:30-3:00
22. Bowman, Reed¹, Nathalie Hamel^1,2, and Michelle L. Dent¹. ¹Archbold Biological Station, ²Department of Aquatic and Fisheries Science, University of Washington. Dispersal patterns among and within perceptual neighborhoods of Florida scrub-jays in a fragmented landscape.

Dispersal decisions in cooperative breeding birds are influenced by the intrinsic benefits of delaying dispersal and the extrinsic constraints on finding high-quality breeding opportunities. Intrinsic benefits may vary little among populations but variation in extrinsic constraints, such as demography, population density and dispersion, and landscape configurations, all of which may influence movements, may vary greatly. Habitat fragmentation is likely to influence many of these extrinsic constraints because patches are likely to vary in quality; thus the relative costs and benefits of different dispersal strategies may vary among patches. We used multi-model selection criteria using AIC to examine influences on the probability of dispersing within and among perceptual neighborhoods in both male and female Florida scrub-jays (Aphelocoma coerulescens). Males were less likely to disperse beyond their perceptual neighborhood than females. Among males, those dispersing outside of their perceptual neighborhood were less successful at obtaining breeding space and had reduced fitness than males dispersing within their neighborhood. These parameters did not differ among females. The best fit models suggested younger, potentially subordinate  males tend to leave high-quality, relatively large neighborhoods with many potential competitors for breeding vacancies. Males may leave to avoid competition. Females tend to leave poor-quality, relatively small neighborhoods where potential mate choices may be limited. Females may leave to improve their reproductive prospects. Landscape variables such as the relative isolation of neighborhoods or the permeability of the surrounding landscape appeared not to influence dispersal decisions of either sex.

3:00-3:30 BREAK

3:30-4:00
23. Rickey, Marcia, Eric S. Menges, and Carl W. Weekley. Archbold Biological Station. Experimental restoration of Florida sandhill using subcanopy felling and burning.

Our “Saw and Burn” project is an experimental sandhill restoration comparing vegetation responses to three treatments: prescribed fire with felling of the oak subcanopy (saw & burn), prescribed fire alone (burn-only) and an untreated control. Our restoration goals are to retain longleaf pines but reduce hardwood subcanopy, decrease shrub cover, increase graminoid and herb cover, and provide habitat for rare sandhill endemics. We collected pre-treatment data in spring 2001, and post-treatment data annually during 2002-2004 on community structure and species composition. More longleaf pines were killed in the saw & burn (45%) than in the burn-only (24%). Chainsaw felling eliminated the subcanopy in the saw & burn treatment and subcanopy stems were lower post-treatment in the burn-only than in the control. Shrub height decreased significantly in the burn-only and saw & burn treatments in 2002, but increased in 2003 and 2004 to levels higher than pre-treatment. In 2002 and 2003, the burn-only and saw & burn treatments had significantly more woody stems <50cm in height than the control. There were no significant differences in herb stems or graminoid cover among treatments or over years. Lichens were eliminated in the saw & burn treatment and decreased in the burn-only. Land managers using chain-saw felling in restoration may reduce longleaf pine mortality by raking around the tree base. Repeated burns combined with partial subcanopy felling may be necessary in the early stages of restoration of long-unburned sandhill to reduce the shrub density and increase graminoids and herbs.

4:00-4:30
24. Deyrup, Mark A. Archbold Biological Station. Insect-flower relationships at the Archbold Biological Station.

 For over 20 years researchers in the bug lab have periodically observed flowers at Archbold. Waiting quietly by a patch of flowers, these scientists pounce on any insect that visits the flowers. OK, so this is not a sophisticated technique, and it is less of a long-term study than one that takes a long time. Over the years, however, records have accumulated on over 160 species of flowers, and many more species of insects. So far, only the records of the 113 species of bees at Archbold have been analyzed, but there is material in the collection to survey records of a larger number of species of wasps, flies and beetles. Here are a few of the interesting patterns that have emerged during this study. There are no cases of plants and insects that both share an exclusive relationship. At Archbold almost as many species of flies as bees feed on pollen. Nectar and pollen robbing are not uncommon. Insects may be specialists at Archbold that are more generalist elsewhere. Few exotic insects are involved, but two of these may be superabundant. Exotic plants may be visited by large numbers of native insects. Some plants appear to produce pollen that is unattractive to insects. Many insects are probably serially oligolectic over the year. Most of the larger insects found on flowers belong to mimetic complexes.