Habitat Use and Effects of Prescribed Fire on Black Bears in Northwestern Florida

I determined food habits, habitat use, and the effects of fire on habitat use by Florida black bears (Ursus americanus floridanus) on Eglin Air Force Base (Eglin), Florida from November 1994 to October 1996. I determined the annual and seasonal diet of bears from 259 scats collected on Eglin. Annual diet was dominated by shrub/vine fruit (38%) and tree fruit (34%). Spring diets were dominated by debris, fleshy material (hearts) of saw palmetto (Serenoa repens) beetles (Coleoptera), and yellow jackets (Hymenoptera). Blueberries (Vaccinium spp.) dominated the early summer diet, whereas sweet gallberry (Ilex coriacea) and acorns (Quercus spp.) dominated the late summer diet. Acorns and saw palmetto berries dominated the fall diet accounting for 93% of the diet by volume. Winter scats were dominated by saw palmetto and greenbriar berries (Smilax spp.). Vegetation, primarily the hearts of saw palmetto and gallberry leaves accounted for 27% by volume. The dominance of saw palmetto berries in the 1994 fall diet indicates that bears selected saw palmetto over acorns as the primary fall food whenavailable. I used a GIS and compositional analysis to determine annual habitat use from 1,891 location estimates of 9 bears (3F, 6M). To determine seasonal habitat use, 1,049 location estimates of 10 bears (3F, 7M) for summer and 794 location estimates of 10 bears (3F, 7M) for fall were used. Nonrandom use was detected for annual (P ≤ 0.0027), summer (P ≤ 0.0002), and fall (P ≤ 0.0006) habitat use. Compositional analysis ranked habitats for annual use in the following order: riparian zones \u3e swamps \u3e pine plantations \u3e sandhills \u3e open areas. There was a difference (P ≤ 0.025) in annual use between riparian zones and swamps and each showed greater use than the remaining habitat associations. Riparian zones and swamps also ranked highest for summer and fall seasons. Riparian zones provided an abundant food supply, escape cover, and denning habitat. The decrease in vegetation density along the edges of riparian zones allowed bears to travel more efficiently within their home range. Pine plantations containing slash pine (Pinus elliottii) were used more than sandhills during the summer season. The 3-5 year burning cycle in pine habitats allowed many soft mast species to reach maximum production. The lower use of sandhills during the summer was attributed to the higher frequency of fire. Frequent burning in sandhills reduced the amount of soft mast available to bears. The use of sandhills was highest during the fall season, ranking third in use. This coincided with the availability of oak hard mast and saw palmetto berries. Open areas were used significantly less than all other habitat associations during the summer and fall seasons. The low use of open areas was attributed to the lack of sufficient cover. I used a GIS and compositional analysis to determined the annual and seasonal use of prescribed burns conducted from 1988 to 1996 by black bears on Eglin. Nonrandom use (P ≤ 0.05) was detected in all years except 1991 and 1995 for annual habitat use. Burned areas ranked highest for years 1989 ( 6-year-old burns) and 1993 (2-year-old burns), ranking 3rd and 4th, respectively. Burned areas generally ranked higher than open areas but lower than all other habitat types. Seasonal habitat use of burned areas ranked 1993 (2-year-old burns) and 1995 ( The most frequently used burned areas were those adjacent to riparian zones and swamps. The strong dependence on these areas for escape cover may have outweighed any deleterious effects burns may have caused. Prescribed burning can be detrimental to bears during the winter denning season. An adult female bear abandoned her den following a prescribed burn. In light of the above results management strategies are discussed that may increase the availability of soft and hard mast and improve habitat quality for black bears on Eglin

Scientific rationale for Uranus and Neptune <i>in situ</i> explorations

The ice giants Uranus and Neptune are the least understood class of planets in our solar system but the most frequently observed type of exoplanets. Presumed to have a small rocky core, a deep interior comprising ∼70% heavy elements surrounded by a more dilute outer envelope of H2 and He, Uranus and Neptune are fundamentally different from the better-explored gas giants Jupiter and Saturn. Because of the lack of dedicated exploration missions, our knowledge of the composition and atmospheric processes of these distant worlds is primarily derived from remote sensing from Earth-based observatories and space telescopes. As a result, Uranus's and Neptune's physical and atmospheric properties remain poorly constrained and their roles in the evolution of the Solar System not well understood. Exploration of an ice giant system is therefore a high-priority science objective as these systems (including the magnetosphere, satellites, rings, atmosphere, and interior) challenge our understanding of planetary formation and evolution. Here we describe the main scientific goals to be addressed by a future in situ exploration of an ice giant. An atmospheric entry probe targeting the 10-bar level, about 5 scale heights beneath the tropopause, would yield insight into two broad themes: i) the formation history of the ice giants and, in a broader extent, that of the Solar System, and ii) the processes at play in planetary atmospheres. The probe would descend under parachute to measure composition, structure, and dynamics, with data returned to Earth using a Carrier Relay Spacecraft as a relay station. In addition, possible mission concepts and partnerships are presented, and a strawman ice-giant probe payload is described. An ice-giant atmospheric probe could represent a significant ESA contribution to a future NASA ice-giant flagship mission