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Biomedical subjects

W M Block

Publications and source records attributed to W M Block.

9 recordsLinked to original sources

Adaptive management on public lands in the United States: commitment or rhetoric?

Adaptive management (AM) is the process of implementing land management activities in incremental steps and evaluating whether desired outcomes are being achieved at each step. If conditions deviate substantially from predictions, management activities are adjusted to achieve the desired outcomes. Thus, AM is a kind of monitoring, an activity that land management agencies have done poorly for the most part, at least with respect to ground-based monitoring. Will they do better in the future? We doubt it unless costs, personnel, and future commitment are seriously addressed. Because ecosystem responses to management impacts can ripple into the distant future, monitoring programs that address only the near future (e.g., 10-20 years), are probably unreliable for making statements about resource conditions in the distant future. We give examples of this. Feedback loops between ecosystem response and adjustment of management actions are often broken, and therefore AM again fails. Successful ground-based monitoring must address these and other points that agencies commonly ignore. As part of the solution, publics distrustful of agency activities should be included in any monitoring program.

Conservation of Natural Resources↗

Survey of birds and lizards for ixodid ticks (Acari) and spirochetal infection in northern California.

A total of 138 birds (24 species) was captured in an oak woodland between December 1988 and June 1989 at the University of California, Sierra Foothill Range Field Station, Yuba County, Calif. Ticks were not found on 71 birds captured between December 1988 and March 1989. Five subadult Ixodes pacificus Cooley & Kohls were removed from 3 of 67 birds caught between April and June 1989. These three birds, an orange-crowned warbler (Vermivora celata (Say], a lazuli bunting (Passerina amoena (Say], and a chipping sparrow (Spizella passerina (Bechstein], represent new host records for I. pacificus in California. Tissues from two ticks and thick blood films prepared from 126 birds tested negative for spirochetes by direct immunofluorescence (DI). A total of 172 larval and 197 nymphal I. pacificus was removed from 15 of 16 western fence lizards (Sceloporus occidentalis Baird & Girard) caught between April and June 1989 in the same location as were birds. Thick blood films prepared from all 16 lizards and tissue smears from 334 of the ticks (143 larvae and 191 nymphs) were DI test-negative for spirochetes. One (1.1%) of 93 adult I. pacificus collected at the bird-lizard capture site in February 1989 was infected with spirochetes that resembled B. burgdorferi.

Animals↗