Evans M.E.K.,Ecole Normale Superieure de Paris |
Evans M.E.K.,Yale University |
Holsinger K.E.,University of Connecticut |
Menges E.S.,Archbold Biological Station
Ecological Monographs | Year: 2010
Understanding and predicting changes in the abundance of natural populations is a central goal of ecology. These changes are influenced by a variety of exogenous processes (weather, floods, fire); variation in these processes leads to variation in vital rates (survival, fecundity) that may be positively or negatively correlated across the life cycle. We used 20 years of data and a hierarchical Bayesian model to estimate vital rates and their covariation in an endangered plant, Dicerandra frutescens ssp. frutescens (Lamiaceae), as a function of time since fire and random year effects. Germination and the number of flowering branches declined with time since fire, and all plants were increasingly likely to become nonreproductive with time since fire. Time since fire had negative effects on survival of seedlings, vegetative plants, and small flowering plants, and positive effects on survival of medium and large flowering plants. Model comparison strongly supported inclusion of time-since-fire effects and weakly supported inclusion of year effects influencing all vital rates ("model-wide" year effects). We used samples from the joint posterior distribution of model parameters to simulate population dynamics as a function of fire regime and year-to-year environmental variation. These simulations suggest that populations of Dicerandra frutescens ssp. Frutescens are least likely to go extinct if the average time between fires is ∼24-30 years. The design of the simulations allowed us to distinguish variation in stochastic population growth associated with process variability (fire, year effects, and demographic stochasticity) from variation associated with parameter uncertainty (finite amounts of data). Even with 20 years of data, half or more of the uncertainty in population growth rates was due to parameter uncertainty. This hierarchical Bayesian population viability analysis illustrates a general analytical framework for (1) estimating vital rates as a function of an exogenous environmental factor, (2) accounting for covariation among vital rates, and (3) simulating population dynamics as a function of stochastic environmental processes while taking into account uncertainty about their effects. We discuss future areas of development for this approach. © 2010 by the Ecological Society of America.
Dee J.R.,Oklahoma State University |
Menges E.S.,Archbold Biological Station
Journal of Vegetation Science | Year: 2014
Questions: The ecology of landscape gaps is important for the maintenance of species diversity in a variety of plant ecosystems. In the scrubby flatwoods community type of the pyrogenic Florida scrub,we aimed to identify the relationship between time-since-fire, gap area, quality (microhabitat) and aggregation (structural connectivity) with neighbouring gaps on gap species diversity and occupancy. Location: Archbold Biological Station (ABS), Lake Wales Ridge, south-central Florida, USA. Methods: We measured species diversity, gap area, aggregation and microhabitat (percentage bare sand) in 120 gaps divided evenly amongst 1, 2, 4, 8, 16 and 26 yrs since fire in the scrubby flatwoods of ABS (typical fire return interval of 5-20 yrs) throughout the summer of 2011. Results: Gap area and aggregation were significantly highest in the first 4 yrs after fire, but decreased and remained fairly constant at longer times-since-fire. Percentage bare sand gradually decreased with time-since-fire until a strong decline at the 26-yr mark, where litter cover was significantly higher than all previous years. Gap area strongly and positively predicted species richness (total and herb spp.) and total species diversity (H'). Bare sand content was positively correlated with the richness of species that are obligate seeders post-fire. Gap aggregation was generally a poor predictor of diversity components, although it positively influenced the occurrence of Stipulicida setacea, a seeder species that occasionally resprouts after fire. Overall, species richness and diversity peaked at intermediate times-since-fire, probably because long-unburned gaps were too small and inundated with litter to sustain higher richness of herbs and obligate seeders. Conclusion: In a prior gap ecology study, in neighbouring more xeric rosemary scrub, gaps were larger, more persistent and had higher bare sand cover, resulting in higher levels of total species richness and diversity for decades longer after fire than gaps in this study. In both these types of Florida scrub, the threat of fire suppression and its adverse effects on gap area and microhabitat may be detrimental for several endemic species that depend on gaps. © 2014 International Association for Vegetation Science.
Coulon A.,Cornell University |
Coulon A.,CNRS Mechanical Adaptation and Evolution |
Fitzpatrick J.W.,Cornell University |
Bowman R.,Archbold Biological Station |
Lovette I.J.,Cornell University
Conservation Biology | Year: 2010
Studies comparing dispersal in fragmented versus unfragmented landscapes show that habitat fragmentation alters the dispersal behavior of many species. We used two complementary approaches to explore Florida Scrub-Jay (Aphelocoma cœrulescens) dispersal in relation to landscape fragmentation. First, we compared dispersal distances of color-marked individuals in intensively monitored continuous and fragmented landscapes. Second, we estimated effective dispersal relative to the degree of fragmentation (as inferred from two landscape indexes: proportion of study site covered with Florida Scrub-Jay habitat and mean distance to nearest habitat patch within each study site) by comparing genetic isolation-by-distance regressions among 13 study sites having a range of landscape structures. Among color-banded individuals, dispersal distances were greater in fragmented versus continuous landscapes, a result consistent with other studies. Nevertheless, genetic analyses revealed that effective dispersal decreases as the proportion of habitat in the landscape decreases. These results suggest that although individual Florida Scrub-Jays may disperse farther as fragmentation increases, those that do so are less successful as breeders than those that disperse short distances. Our study highlights the importance of combining observational data with genetic inferences when evaluating the complex biological and life-history implications of dispersal. ©2010 Society for Conservation Biology.
Hohausova E.,Academy of Sciences of the Czech Republic |
Lavoy R.J.,Archbold Biological Station |
Allen M.S.,University of Florida
Marine and Freshwater Research | Year: 2010
Knowledge of fish dispersal routes when exploiting temporary habitat is important for understanding the ecology of species and for designing and conducting conservation and land-management activities. We evaluated fish dispersal in a network of seasonal habitats and a permanent fish source (a lake) in a subtropical wetland, in Florida, sampled biweekly from May 2002 to May 2003. Fish dispersal routes were influenced by (1) local physical conditions, (2) anthropogenic alterations and (3) fish species and size. Fish from the source dispersed into 9 of the 25 seasonal sites evaluated, via temporarily formed dispersal corridors between the source and the sites. Low connection depths along the corridors were a key factor, allowing small-bodied species (e.g. Gambusia holbrooki, Elassoma evergladei) to travel farther than large-bodied fish (e.g. Erimyzon sucetta, Lepomis macrochirus). Fish travelled distances of 0.7-4 km. Anthropogenic structures both enhanced (ditches, sand roads) and blocked (a railroad, soil dumps) fish dispersal routes. We demonstrated extensive opportunistic use by fish of seasonal wetlands. Our results indicated that anthropogenic alterations to the landscape can provide habitat for native fish and also allow dispersal of non-native fish and thus should be implemented with care. © 2010 CSIRO.
Edwards C.E.,Environmental Laboratory |
Parchman T.L.,University of Wyoming |
Weekley C.W.,Archbold Biological Station
DNA Research | Year: 2012
Large-scale DNA sequence data may enable development of genetic resources in endangered species, thereby facilitating conservation efforts. Ziziphus celata, a federally endangered, self-incompatible plant species occurring in Florida, USA, is one species for which genetic resources are necessary to facilitate new introductions and augmentations essential for recovery of the species. We used 454 pyrosequencing of a Z. celata normalized floral cDNA library to create a genomic resource for gene and marker discovery. A half-plate GS-FLX Titanium run yielded 655 337 reads averaging 250 bp. A total of 474 025 reads were assembled de novo into 84 645 contigs averaging 408 bp, while 181 312 reads remained unassembled. Forty-seven and 43% of contig consensus sequences had BLAST matches to known proteins in the Uniref50 and TAIR9 annotated protein databases, respectively; many contigs fully represented orthologous proteins in TAIR9. A total of 22 707 unique genes were sequenced, indicating substantial coverage of the Z. celata transcriptome. We detected single-nucleotide polymorphisms and simple sequence repeats (SSRs) and developed thousands of SSR primers for use in future genetic studies. As a first step towards understanding self-incompatibility in Z. celata, we identified sequences belonging to the gene family encoding self-incompatibility. This study demonstrates the efficacy of 454 transcriptome sequencing for rapid gene and marker discovery in an endangered plant. © 2011 The Author.
Deyrup M.,Archbold Biological Station
Florida Entomologist | Year: 2015
A new species of ant, Myrmecina cooperi sp. nov. (Hymenoptera: Formicidae: Myrmecinae) is described and illustrated from specimens collected in Florida and Alabama, USA. This species is characterized by its small size (under 2 mm length), shagreened gastral tergites, and a strong ventral protrusion on the underside of the postpetiole. It is presently known from a small area in the Florida Panhandle and adjacent Alabama. Habitus illustrations and an identification key are provided for the 3 eastern species of Myrmecina.
Weekley C.W.,Archbold Biological Station |
Menges E.S.,Archbold Biological Station
Australian Journal of Botany | Year: 2012
Fire drives the population dynamics of many plants. By following successive cohorts of Polygala lewtonii Small (Polygalaceae), a short-lived herb endemic to fire-maintained Florida sandhills, in both burned and unburned microsites, we investigated how fire affected vital rates throughout cohort lifetimes. We followed cohorts from before to 6 years after a prescribed fire in 220 25-cm-radius quadrats, recording survival and seedling recruitment quarterly, and growth and fecundity annually. Fire effects were most pronounced in the first 2 post-burn quarterly censuses, when cohorts in burned (v. unburned) quadrats had seven-fold higher seedling recruitment, significantly higher seedling survival, and a 16.7% gain (v. 1.2% loss) in quadrat occupancy. Plants in burned (v. unburned) quadrats also flowered earlier, were more likely to survive to reproduce and had longer lifespans. The negative effects of density on survival were relaxed in burned quadrats for the first 2 censuses. Burning creates contrasting demographic trajectories for burned v. unburned cohorts. In burned microsites, higher seedling recruitment and survival, earlier flowering and longer lifespans combine to produce a greater contribution to the seedbank and, thus, to population viability. The present study documents the pyro-demographic mechanisms linking the life history of a perennial herb with a frequent fire regime. © 2012 CSIRO.
Agency: NSF | Branch: Standard Grant | Program: | Phase: LONG-TERM RSCH IN ENVIR BIO | Award Amount: 335.75K | Year: 2014
Long-term data provide a valuable context to understand how landscapes and species adjust to variation in climate, changing land use, and a variety of disturbances. This project extends a twenty-six year study of 14 plant species by combining experiments with models to understand the effects of local and regional variation on plant population dynamics. Field experiments will vary water and ash addition and removal, competition, and seed additions. Survival, growth, fecundity, and recruitment will be measured in both undisturbed populations and experimental treatments, and these small-scale responses will then be linked with larger-scale changes in climate and fire regimes. Long-term data and experimental results will inform models that predict how different fire and climate conditions affect key plant species. In general, this research takes advantage of long-term demographic data on multiple co-occurring plant species to reveal how plants respond across different spatial scales to environmental change.
The research incorporates education efforts at multiple levels. It will support high school research assistants each summer and will fund post-baccalaureate interns, continuing a unique, highly productive, in-depth research experience. Graduate students will be trained through their participation in the research. The project will provide a wealth of statistical, ecological, and conservation information, contributing directly to conservation of Florida scrub, an imperiled ecosystem that is home to dozens of endangered species. Specialized workshops and continual interaction with local land managers and policy makers through collaborations and presentations will increase the practical value of the research findings. Specifically, the project will inform land managers using fire and other tools to conserve critically threatened plants. Public displays and art projects will directly convey information to the general public.
Agency: NSF | Branch: Continuing grant | Program: | Phase: BIOLOGICAL RESEARCH COLLECTION | Award Amount: 449.16K | Year: 2015
An award is made to the Archbold Biological Station (ABS), an internationally recognized not-for-profit biological field station in central Florida, to preserve and secure a unique, irreplaceable record of life in the Florida Scrub habitat of the Lake Wales Ridge, one of the Nations most imperiled ecosystems. The project targets approximately 270,000 specimens including arthropods plants, mammals, birds, fish, and reptiles. Specimens will be digitized and imaged to increase online access to information about this unique collection from the Florida Scrub and surrounding environs. Activities proposed will enhance advances in the biological sciences, promote benefits to conservation, and increase educational outreach. For example, by offering more opportunities for use of the collection to inform research projects and other forms of student engagement, ABSs programs for students will be strengthened. Furthermore, information about the collection will be shared during workshops with regional land managers and ABS will increase access to teaching specimens and exhibits for K-12 students.
This award will allow Archbold Biological Station to curate and digitize its diverse collection. This digitization effort will improve data accessibility to researchers and educators. A major focus of this project will be the arthropod collection (specifically the ants, scrub endemics, insect-flower visitors and dead wood insects) but other taxonomic groups will also be secured. Partnering with iDigBio will enable ABS to effectively database, image and migrate specimen data to the Internet. Symbiota-linked portals will augment the ABS website, providing an excellent example of what a regional field station collection can achieve. By posting the collection data online, ABS will make available a virtually complete biodiversity record and rich ecological data, enabling studies of biodiversity in ways that would be difficult to otherwise replicate. This increase in accessibility will also benefit educators and the conservation community.
Agency: NSF | Branch: Standard Grant | Program: | Phase: | Award Amount: 99.62K | Year: 2014
Archbold Biological Station in south central Florida is awarded a grant to enhance its computer network to expand data integration, enhance research collaboration, and improve student training. Archbold is an independent research, education, and conservation organization with a 73-year history of long-term ecological research. A multimedia server with Adobe Creative Cloud will improve image archiving and cataloguing to enable searches of Archbolds impressive archive of images and videos, so they can be accessible to researchers, educators, conservationists, and the public. Archbold maintains a database for seamless data management and online data access; a new server will speed up access to searchable environmental and research data, providing growing room for inevitable future demands on data storage. A new Virtual Private Network will allow secure offsite access to the network for remote users such as research collaborators and students, and for staff when traveling or working from home. A large archive server will house static media like orthophotos in a repository. Finally the Station will move to an enhanced disk-based backup to increase the efficiency of backups and improve security and disaster recovery.
The network enhancements will enhance Archbolds ability to work collaboratively among staff science teams and outside researchers and students, enabling new synthesis and fermenting new ideas. The enhancements will further interactions with scientists at more than 50 universities and research institutions currently working with Archbold, including important research networks that Archbold is a member of such as the Global Lakes Ecological Observatory Network GLEON and the newly-formed USDA Long-Term Agro-ecosystem Research Network. Students being trained at Archbold, mostly graduates from universities around North America in the Stations post-baccalaureate program, will integrate more closely into home institutions and with large science teams. Research collaborations meeting at the Stations conference facilities will experience better support to enable science interactions.
Archbolds extensive education, outreach, and conservation programs will benefit directly from the enhanced infrastructure. Education programs disseminate Archbold science directly to the public, involving thousands of students annually (K-Gray) in the process of science. Improved access to collections of videos and imagery will be vital to the many creative teams working with Archbold to enhance science communication. This will also help build the programs (Arts-Science Alliance) that attract artists and photographers. Public visitors to the Stations Learning Center learn about on-site research via high quality interpretive signage and many public events. The award will enhance the web site providing a richer focus on information and education materials. Overall this award to improve IT capacity will have wide-ranging impact on Archbolds substantial education, outreach, and conservation programs. For further information about Archbold, please visit the website at http://www.archbold-station.org.