“Berry Patch” As a Kind of Place—the Ethnoecology of Black Huckleberry in Northwestern Canada

The Gitksan and Wet’suwet’en of Northwestern British Columbia formerly used landscape burning to manage patches of black huckleberry (Vaccinium membranaceum), the most important plant resource of their seasonal round. In view of its significance one might postulate that managed sites would conform to a biophysical or ecological type to maximize return for effort. However, a survey of a number of traditionally managed sites indicated that managed sites are characterized by wide variation in biophysical attributes including elevation, aspect and moisture regime, while proximity to fishing sites, village sites, or sites for harvest of alpine resources proved to be a common factor in known historic berry patch sites. We conclude that characterization of the ideal site type for aboriginal V. membranaceum management must include the economy and social institutions of the local First Nations and requires an enhanced appreciation for the sophistication of the strategies and techniques employed in their management and utilization of the species.

Intracellular and extracellular labeling of neurons in fresh slice preparations combined with multiple tract tracing

We describe methods for studying axo-dendritic projections, one of the forms of neural connection involved in the complex circuits of the central nervous system, including brainstem auditory pathways. This form of neural connection is often difficult to visualize by conventional tract tracing techniques. Retrogradely identified cells were filled intracellularly with a mixture of fluorescent Lucifer yellow and nonfluorescent HRP in live slice preparations to reveal the detailed morphological features of these cells with special attention to the distal dendrite that may receive projections from suspected or known input axons. Extracellular or intracellular labeling of cells with axons that project to the distal dendrite of the identified cells was accomplished in the same live slice preparation. Using a live slice rather than a fixed slice allows accurate, visually controlled placement of anterograde tracer, which requires living axons for transport, into the source of input to the identified cells within the slice. Live slices also permit one to characterize the identified cells electrophysiologically. Intracellular labeling of cells in a potential source of local input to the identified cells also provides conclusive information concerning with connections of the cells involved.     

Historical Ecology, Responses to Current Ecological Changes and Conservation of Australian Spiders

In response to geohistorical events from the Mesozoic through the Tertiary with contraction of mesic forest to southwestern and eastern montane and coastal regions, and expansion of woodlands and xeric shrublands, nobreak Australian spiders today comprise relict families and genera (confined to Gondwanan habitats and refuges) along with later evolved representatives which have adapted to changing environments. Tropical relicts also persist in refugia in the arid interior while some spiders (both mygalomorphs and araneomorphs) have adapted to arid conditions, mainly through specialized behaviours. Although fire has become increasingly a phenomenon of the Australian environment it is doubtful whether any spiders are adapted to fire per se. European settlement has impacted differentially on relictual and later evolved representatives; a few species, including the funnelweb (Atrax robustus) and redback spider (Latrodectus hasselti) have benefited through enhanced habitat opportunities and some species of Badumna and other genera have become synanthropic. It is suggested that conservation strategies need to consider the ecoevolutionary history of particular spiders and their natural vulnerability or resilience to environmental factors.     

Elevationally biased avian predation as a contributor to the spatial distribution of geometrid moth outbreaks in sub‐arctic mountain birch forest

1. Population dynamics and interactions that vary over a species' range are of particular importance in the context of latitudinal clines in biological diversity. Winter moth (Operophtera brumata) and autumnal moth (Epirrita autumnata) are two species of eruptive geometrids that vary widely in outbreak tendency over their range, which generally increases from south to north and with elevation. 2. The predation pressure on geometrid larvae and pupae over an elevational gradient was tested. The effects of background larval density and bird occupancy of monitoring nest boxes on predation rates were also tested. Predation on larvae was tested through exclusion treatments at 20 replicate stations over four elevations at one site, while pupae were set out to measure predation at two elevations at three sites. 3. Larval densities were reduced by bird predation at three lower elevations, but not at the highest elevation, and predation rates were 1.9 times higher at the lowest elevation than at the highest elevation. The rate of predation on larvae was not related to background larval density or nest box occupancy, although there were more eggs and chicks at the lowest elevation. There were no consistent differences in predation on pupae by elevation. 4. These results suggest that elevational variation in avian predation pressure on larvae may help to drive elevational differences in outbreak tendency, and that birds may play a more important role in geometrid population dynamics than the focus on invertebrate and soil predators of previous work would suggest.     

Phototropism in fishes,and its relation to the results obtained by eye-dislocation

Summary In the case of viviparous perch and goldfish, unilateral blinding causes a tilting on the anterior-posterior axis towards the normal eye, the amount of tilting being dependent upon the intensity of light. With a sudden change to a greater intensity of light, the fish circle toward the blind eye, and upon sudden reduction of the intensity they often circle toward the normal eye. The similarity of this reaction to the effect of unilateral blinding of insects is offered as an explanation.It is suggested that these results explain the experiments of Pearcy and Koppanyi. These workers dislocated one eye of a goldfish and removed the other one, explaining the consequent tilting of the fish as due to an attempt of the animal to regain its normal visual field. Since the fish was now totally blind, due to the effect of the operation, no tilting was present. As the dislocated eye. gradually recovered its vision, the fish began to tilt, reaching maximal tilting several weeks afterwards. However, since I have produced tilting by unilateral blinding alone, it seems evident that the results obtained by those two experimenters were also due to unilateral blinding, and not to dislocation of the eye.I am indebted to Dr. A. R. Moore both for the suggestion of the problem and for advice during the experiments.