Abstract We tested whether the intensity of hardwood midstory reduction causes commensurate improvements herbaceous groundcover in fire‐suppressed Pinus palustris (longleaf pine) sandhills. Using a complete randomized block design, we compared effects three techniques (spring burning, application ULW ® form herbicide hexazinone, chainsaw felling/girdling) and no‐treatment control on plant species richness, life common densities at Eglin Air Force Base, Florida, U.S.A., from 1995 to 1998....

The ecological restoration of fire-suppressed habitats may require a multifaceted approach. Removal hardwood trees together with reintroduction fire has been suggested as method restoring longleaf pine (Pinus palustris) forests; however, this strategy, although widespread, not evaluated on large spatial and temporal scales. We used landscape-scale experimental design to examine how bird assemblages in sandhills responded alone or following mechanical removal herbicide application reduce...

ABSTRACT This study tested the hypothesis that stable C and N isotope values in surface soil litter would be increased by fire due to volatilization of lighter isotopes. The was by: (1) performing experimental laboratory burns organic mineral materials from a watershed at combinations temperature ranging 100 600°C duration 1 60 min; (2) testing field samples upland soils before, shortly after, yr following wildfire same watershed; (3) down‐gradient ash/sediment depositional area riparian...

Measuring the effects of ecological restoration on wildlife assemblages requires study broad temporal and spatial scales. Longleaf pine (Pinus palustris) forests are imperiled due to fire suppression subsequent invasion by hardwood trees. We employed a landscape-scale, randomized-block design identify how reptile initially responded treatments including removal trees via mechanical methods (felling girdling), application herbicides, or prescribed burning alone. Then, we examined after all...

Abstract The hypothesis that habitat restoration will provide for community reestablishment and the creation of heterogeneity was examined with regards to herpetofauna longleaf pine sandhills in northwest Florida. herpetofaunal response fire‐suppressed, hardwood‐dominated areas treated (1) spring fire; (2) felling or girdling; (3) a granular form herbicide hexazinone. No‐treatment controls were also included. Felling girdling plots burned fuel reduction two dormant seasons after initial...

Abstract Principal components analysis was used to assess niche partitioning between four aphid predators on the basis of oviposition strategies. The study conducted by sampling abundance and position eggs these in corn monocultures two locations southern Quebec. results indicated that chrysopid Chrysopa occulata Say laid its leaves usually without colonies, late season. All other reacted concentrations. syrphid Sphaerophoria philanthus (Mg.) oviposited close ground, early season, among...

We investigated by computer simulations and a field experiment the hypothesis that species assemblage of generalist predators imposes more mortality on prey populations than single does. The simulation tracked energetics individual spiders feeding in patchy variable habitat. Simulation tests showed increasing number spider variability body sizes contributed Significantly to greater limitation survival. Higher had reverse effect mixed effects. Large spiders, although less abundant smaller...

The dramatic loss and degradation of longleaf pine (Pinus palustris) forests in the southeastern United States have contributed to declines several bird species associated with this ecosystem. We examined breeding response habitat restoration sandhill northwest Florida, USA. compared variables abundance birds among 3 hardwood reduction techniques (prescribed spring burning, herbicide application, mechanical felling-girdling) maintenance fire exclusion (control). also fire-maintained,...

Abstract: Soil characteristics, disturbance histories, and species richness among distinct groups of plants animals may be useful predictors important conservation areas when data are limited. We used multivariate analysis covariance to test the hypothesis that plants, arthropods, herpetofauna, breeding birds correlated increase with soil fertility (silt clay content in sandy soils), variability, hardwood midstory reduction subxeric, nutrient‐poor longleaf pine sandhills at Eglin Air Force...

We constructed a model of territoriality relating the probability starvation in nonstationary, variable environment to costs and benefits feeding, defense, exploration their variances. The suggests that survival territory increases with increasing food abundance decreasing defense costs. Territoriality, risk-averse behavior, is favored when an animal's net expected energy balance positive (see also Stephens 1981). When negative, risk-prone abandoning become marginal or floater, appropriate....

Abstract In the Great Basin of western United States, expansion Pinus monophylla (singleleaf piñyon) and Juniperus osteosperma (Utah juniper) out historic woodlands into Artemisia spp. (sagebrush) shrubland communities can facilitate invasion exotic downy brome ( Bromus tectorum ) lead to decreases in ecological economic values shrublands. This has, therefore, been focus management efforts, including thinning or removal trees areas that were historically shrubland. Our study examined effects...

The mechanisms by which spiders limit prey populations were investigated with specific reference to the criteria required for equilibrium point control, a predator–prey model in food-web literature that explains top-down effects on lower trophic levels. In this paper we review results of previous studies demonstrate meet two four control: (1) they are generalist feeders, and (2) self-damped. We further present experimental evidence other (3) respond temporal spatial patterns availability,...

Abstract Across much of the southeastern U.S.A., sandhills have become dominated by hardwoods or invasive pine species following logging Pinus palustris (longleaf pine) and fire suppression. At Eglin Air Force Base where this study was conducted, clausa (sand has densely colonized most sandhill sites, suppressing groundcover vegetation. The objectives were: to determine if suppressed vegetation recovers removal P. clausa; compare composition abundance in plots with that reference, high...

Stochastic foraging models, ecophysiology, and previous experimental work concerned with spiders suggested that food deprivation should modify activity. We tested for short-term effects of hunger on the behavior, predation, gain weight Tetragnatha laboriosa (Araneae) in two field experiments. In a first experiment, deprived satiated were exposed to four exclusive temporal prey variability treatments then released enclosures behavioral observations. Food showed greater movement...

Journal Article Functional Responses and Switching of Tetragnatha laboriosa Hentz (Araneae: Tetragnathidae) Clubiona pikei Gertsh Clubionidae) for the Aphids Rhopalosiphum maidis (Fitch) padi (L.) (Homoptera: Aphididae) Get access Louis Provencher, Provencher 1 Université du Québec á Montréal, Département des Sciences Biologiques, C.P. 8888, Succ. A, Quéebec H3C 3P8 Canada 1Current address: Graduate Program in Ecology, Univ. Tennessee, Knoxville, TN 37996-1610. Search other works by this...

We used mid-scale Fire Regime Condition Class (FRCC) mapping to provide Hawthorne Army Depot in the Mount Grant area of Nevada, USA, with data layers plan fuels restoration projects meet resource management goals. FRCC computes an index departure existing conditions from natural range variability, and consists five primary steps: (1) Potential Natural Vegetation Types (PNVT) based on interpretation a soil survey; (2) refining PNVTs additional information; (3) modelling variability (NRV) per...

Historic fire suppression and intensive forest management in longleaf pine (Pinus palustris) sandhill forests has resulted hardwood encroachment degradation of this fire-dependent ecosystem. Active is now required to restore native community structure composition, but little known about the long-term impacts typical restoration techniques on ecosystem properties. In 1994, Longleaf Pine Restoration Project (LPRP) was established fire-excluded sandhills Eglin Air Force Base, Florida, explore...