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The purpose of this study is to see if it is possible to determine the course of forest succession over several hundred years by the dissection and close scrutiny of live and dead plant material. The study area was a one-tenth-acre (0.04-ha) square plot in a forest that had never been cut, located near Ashuelot in southwestern New Hampshire. Within it stem-location and growth-rate data were collected from three different classes of stems: 1) living trees, 2), dead unburied stems and stem fragments, and 3), woody remnants buried in the forest floor. The vegetational history of the plot was reconstructed from before 1665 to 1967. During this time, autogenic succession did not contribute significantly to compositional changes, whereas disturbance was an important mediator of such changes. Furthermore, changes in forest structure were often manifestations of species behavior: each tree species had a distinctive stem-distribution pattern in relation to microtopography, mode of germination, and growth. The approach seemed to provide a useful means to obtain evidence about forest change through time that may help prediction and illuminate ecological theory. Limits and modifications of the procedure are discussed.

The eleven different functions for which mammals use urine marking are reviewed in this paper, and the urine marking behavior of the red fox (Vulpes vulpes) is described in detail. A new hypothesis is advanced that urine marking may serve as a "book keeping system" in the red fox's scavenging behavior. Foxes consistently investigate and urine mark inedible food remnants (e.g., bones, bird wings, and dried out pieces of hide). When a fox re-investigates a marked remnant, the urine mark signals "no food present," and the fox investigates this object for only a brief period of time. This use of urine marking may increase the efficiency of its scavenging behavior, i.e. more food-items found per hour of scavenging. This efficiency may be particularly important during periods of food shortage. The hypothesis is tested in three different experiments, using free-ranging red foxes as subjects. Experiment I establishes that fox do urine mark food remnants. Experiment II shows that foxes investigate for a significantly shorter period of time (P<0.001) food remnants exhibiting both the odor of food and the odor of urine as compared to remnants exhibiting just the odor of food. Experiment III suggests that there a hierarchy of stimuli which determines different responses in the fox's scavenging behavior. The experiments also suggest that there is a degree of social behavior in the scavenging activities of red foxes. Foxes appear to use each other's urine marks to increase the efficiency of their scavenging behavior. Thus this study definitely support LEYHAUSEN'S (1965) statement that the social life of solitary animals is frequently more complex than we realize. Solitary species probably show many ingeniously adapted mechanisms for occupying niches where highly social species could not be maintained. The social evolution and ecological advantages of solitary species deserve to be the focus of future research.

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Chemobehavioural phenotypic analysis using small aquatic model organisms is becoming an important toolbox in aquatic ecotoxicology and neuroactive drug discovery. The analysis of the organisms’ behavior is usually performed by combining digital video recording with animal tracking software. This software detects the organisms in the video frames, and reconstructs their movement trajectory using image processing algorithms. In this work we investigated the impact of video file characteristics, video optimization techniques and differences in animal tracking algorithms on the accuracy of quantitative neurobehavioural endpoints. We employed larval stages of a free-swimming euryhaline crustacean Artemia franciscana,commonly used for marine ecotoxicity testing, as a proxy modelto assess the effects of video analytics on quantitative behavioural parameters. We evaluated parameters such as data processing speed, tracking precision, capability to perform high-throughput batch processing of video files. Using a model toxicant the software algorithms were also finally benchmarked against one another. Our data indicates that variability in video file parameters; such as resolution, frame rate, file containers types, codecs and compression levels, can be a source of experimental biases in behavioural analysis. Similarly, the variability in data outputs between different tracking algorithms should be taken into account when designing standardized behavioral experiments and conducting chemobehavioural phenotyping.

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