A5007703905- Ecology and Vegetation Dynamics Studies
- Fire effects on ecosystems
- Rangeland and Wildlife Management
- Forest ecology and management
- Plant and animal studies
- Scottish History and National Identity
- Coastal wetland ecosystem dynamics
- Botany, Ecology, and Taxonomy Studies
- Australian History and Society
- Historical Economic and Social Studies
- Plant Water Relations and Carbon Dynamics
- African history and culture analysis
- Folklore, Mythology, and Literature Studies
- Plant Parasitism and Resistance
- Classical Antiquity Studies
- American Constitutional Law and Politics
- Archaeology and Historical Studies
- Tree Root and Stability Studies
- Digital Humanities and Scholarship
- Tree-ring climate responses
- Islamic Studies and History
- Spanish Literature and Culture Studies
- Forest Ecology and Biodiversity Studies
- Historical and Literary Studies
- Irish and British Studies
Louisiana State University
2016-2025
University of Exeter
2015
General Electric (United States)
2015
GE Global Research (United States)
2015
University of California, Riverside
2015
Southern Research Station
1997
University of Buenos Aires
1997
Cary Institute of Ecosystem Studies
1990
Florida State University
1984-1988
Tall Timbers Research Station and Land Conservancy
1984-1988
Light regimes beneath closed canopies and tree-fall gaps are compared for five temperate tropical forests using fish-eye photography of intact forest a model calculating light penetration through idealized gaps. Beneath canopies, analyses canopy photographs indicate that sunflecks potentially contribute 37–68% seasonal total photosynthetically active radiation. In all the forests, potential sunfleck duration is brief (4–6 min), but frequency distributions vary because differences in geometry...
Abstract Fire is a powerful ecological and evolutionary force that regulates organismal traits, population sizes, species interactions, community composition, carbon nutrient cycling ecosystem function. It also presents rapidly growing societal challenge, due to both increasingly destructive wildfires fire exclusion in fire‐dependent ecosystems. As an process, integrates complex feedbacks among biological, social geophysical processes, requiring coordination across several fields scales of...
We investigated the demography and spatial pattern of an old-growth longleaf pine population using a large plot in which all trees at least 2 cm dbh were mapped tagged for individual recognition. The was uneven age size; tree size correlated positively with age. Large or old only loosely aggregated, forming background matrix that filled forest. In contrast, juvenile highly aggregated located areas low adult densities. Recruitment within this thus appears to occur primarily open spaces...
Abstract Biodiversity hotspots are conservation priorities. We identify the North American Coastal Plain ( NACP ) as a global hotspot based on classic definition, region with > 1500 endemic plant species and 70% habitat loss. This has been bypassed in prior designations due to misconceptions myths about its ecology history. These fallacies include: (1) young age of , climatic instability over time submergence during high sea‐level stands; (2) environmental homogeneity; (3) closed forest...
Badger disturbances in a tall—grass prairie were used to study colonization patterns and the formation of equilibrium plant species associations complex mainland community. Colonization processes described from field observations over 4—yr period. A qualitative model was developed predict noninteractive equilibria. Predicted rates based upon relative immigration determined by interactions among propagule production rates, dispersal capacities, source—site distances involved. The both between...
Frequent, low intensity fire was an important component of the natural disturbance regime presettlement savannas and woodlands in southeastern USA dominated by longleaf pine (Pinus palustris), prescribed burning is now a critical part management these endangered habitats. Fire season, frequency, are three potentially important, though still little understood, components both managed regimes. In this long—term (8—yr) study, we experimentally (through use burning) tested for effects season...
Comparisons are made of propagule characteristics and niche relationships among co-occurring species goldenrods (Solidago) in a 23-yr-old field virgin tall-grass prairie. Five the six goldenrod from prairie site same as those found old field, allowing an empirical study differences between "open" "closed" communities postulated by earlier theoretical treatments. In general, each produced fewer heavier propagules with reduced dispersal capacity compared old-field populations. Under increasing...
Badger disturbances on tall-grass prairies constitute a limiting resource for guild of fugitive plants. These plants partition the along several dimensions. Divergent centers utilization result from different suites adaptive life-history characteristics important during colonization. While overlap functions is considerable single dimensions resource, complementary adaptations species in reduced complex gradient integrating separate We predict that number, packing, and organization into will...
The original concept of succession emphasized directional changes in species composition occurring over time on “blank slates” (new substrates or those that followed catastrophic disturbances). In this paper, we explore relationships between different effects disturbances residents and the initiation replacement sites a landscape. We present conceptual model involving recurrent natural landscape containing two species, one which arrives at early other late following disturbance. predict (no...
Savanna models that are based on recurrent disturbances such as fire result in nonequilibrium savannas, but these rarely incorporate vegetation feedbacks frequency or include more than two states (grasses and trees). We develop a disturbance model includes vegetation‐fire feedbacks, using system of differential equations to represent three main components savannas: grasses, fire‐tolerant savanna trees, fire‐intolerant forest trees. investigate the stability savannas presence positive with...
Woody plants in fire-frequented ecosystems commonly resprout from underground organs after fires. Responses to variation characteristics of fire regimes may be a function plant physiological status or intensity. Although these hypotheses have been explored for trees southeastern longleaf pine (Pinus palustris) savannas, responses other life forms and stages not studied. We examined effects season frequency, geography, habitat, organ morphology on resprouting shrubs. In 1994, we located...
Small-scale variation in fire intensity and effects may be an important source of environmental heterogeneity frequently burned plant communities. We hypothesized that resulting from local differences fuel loads produces pine savanna ground cover by altering shrub abundance. To test this hypothesis, we experimentally manipulated prefire to mimic naturally occurring fuel-load associated with branch falls, needle fall near large pines, animal disturbances a longleaf (Pinus palustris)...
Abstract Fire regimes in North American forests are diverse and modern fire records often too short to capture important patterns, trends, feedbacks, drivers of variability. Tree‐ring scars provide valuable perspectives on regimes, including centuries‐long year, season, frequency, severity, size. Here, we introduce the newly compiled tree‐ring fire‐scar network (NAFSN), which contains 2562 sites, >37,000 fire‐scarred trees, covers large parts America. We investigate NAFSN terms geography,...
Factors responsible for patterns of canopy tree replacement were studied 22 yr in Warren Woods, Michigan, USA, and old—growth forest codominated by American beech (Fagus grandifolia) sugar maple (Acer saccharum). Our goal was to distinguish among four hypotheses: autogenic succession, allogenic coexistence, coexistence. We could discern neither successional change toward increasing dominance or beec nor self—replacement root sprouts. In the as a whole, from 1933 1980, remained dominant small...
Disturbances that are strongly linked to global climatic cycles may occur in a regular, predictable manner affects composition and distribution of ecological communities.The El Nin ˜o Southern Oscillation (ENSO) influences worldwide precipitation patterns has occurred with regular periodicity over the last 130 000 years.We hypothesized ENSO, through effects on local weather conditions, influenced frequency extent fires within Everglades National Park (Florida, USA).Using data from 1948 1999,...
Pyrogenic plants dominate many fire-prone ecosystems. Their prevalence suggests some advantage to their enhanced flammability, but researchers have had difficulty tying pyrogenicity individual-level advantages. Based on our review, we propose that flammability in ecosystems should protect the belowground organs and nearby propagules of certain individual during fires. We base this hypothesis five points: (1) by which fire-adapted survive fires are vulnerable elevated soil temperatures fires;...
Summary Fuels in the groundcover of frequently burned south‐eastern pine savannas include shed leaves trees. Flammable needles longleaf ( P inus palustris ) potentially increase maximum fire temperatures and durations heating, negatively affecting other trees within groundcover. Less flammable that accumulate around bases understorey stems hardwood such as mockernut hickories C arya alba fall depress enhancing post‐fire recovery. We experimentally manipulated amounts hickory beneath a...
Fire seasonality, an important characteristic of fire regimes, commonly is delineated using seasons based on single weather variables (rainfall or temperature). We used nonparametric cluster analyses a 17-year (1993–2009) data set that influence likelihoods and spread fires (relative humidity, air temperature, solar radiation, wind speed, soil moisture) to explore seasonality in pine savanna-grassland landscapes at the Avon Park Air Force Range southern Florida. A four-variable, three-season...