Thirty-five species of nearshore, benthic ascidians were collected in Bermuda and notes were made on their habitat, microhabitat, susceptibility to epizoic recruitment, morphology, and acidity. Twenty-four ascidian species were later analyzed for vanadium and iron contents. Ten species had vanadium concentrations of over 100 ppm d. W. (dry weight); three species had vanadium concentrations of o...

For niche differences to maintain coexistence of sympatric species, each species must grow and/or survive better than each of the others in at least one set of conditions (i.e., performance trade-offs). However, the extent of niche differentiation in tropical forests remains highly debated. We present the first test of performance trade-offs for wild seedlings in a tropical forest. We measured ...

This paper quantifies the spatial distribution of zooxanthellae (ZX) and zoochlorellae (ZC), two algal symbionts common to the temperate anemone, Anthopleura xanthogrammica, in relation to shore height. Anemones in tidepools and crevices had varying algal proportions: >0.90 ZC (green anemones), 0.10 to 0.90 ZX (mixed), and >0.90 ZX (brown). Brown anemones are primarily found in the high interti...

An important step in connecting the organismal response to thermal stress to patterns of community structure is determining at what scale discernable levels of variation are manifested. The temperature signal to which organisms may potentially respond varies at many spatial scales including microhabitat, tidal height, site and latitude. A number of studies have taken physiological assessment of...

Vertical zonation of intertidal organisms, from the shallow subtidal to the supralittoral zones, is a ubiquitous feature of temperate and tropical rocky shores. Organisms that live higher on the shore experience larger daily and seasonal fluctuations in microhabitat conditions, due to their greater exposure to terrestrial conditions during emersion. Comparative analyses of the adaptive linkage ...

Recent studies concerned with the ecology of web-building spiders found that specific differences in web structure (see Foelix, 1992 for a summary), spatial distribution (e.g. Enders, 1974; Pasquet, 1984; Ward & Lubin, 1992; Herberstein, 1997a), temporal activity period (e.g. Ward & Lubin, 1992; Herberstein & Elgar, 1994) and species-specific attack behaviour (e.g. Vasconcellos-Neto & Lewinsohn...

1. The effects of the anecic earthworm Lumbricus terrestris L. on plant seedling recruitment and spatial aggregation were investigated in a microcosm glasshouse experiment by varying plant seed size (small and large); functional groups (grasses, legumes, herbs); plant species diversity (1, 3, 6); and plant functional group diversity (1, 3). 2. Generally, earthworms buried seeds quickly irrespec...

— In this paper we analyze the seed dispersal stage of the Prunus mahaleb1 frugivorous bird interaction from fruit removal through seed delivery within the context of 2 disperser effectiveness. The effectiveness of a frugivorous species as a seed disperser is the 3 contribution it makes to plant fitness. Effectiveness depends on the quantity of seed dispersed 4 and the quality of dispersal prov...

Data from gene sequences and morphological structures were collected for the gull feather lice, Saemundssonia lari, Quadraceps punctatus, and Q. ornatus, parasitizing Larus crassirostris and L. schistisagus. Saemundssonia lari was collected from both gull species, and no detectable morphological and genetic differences were found between lice collected from the two different hosts. In contrast,...

'Animal personality' means that individuals differ from one another in either single behaviours or suites of related behaviours in a way that is consistent over time. It is usually assumed that such consistent individual differences in behaviour are driven by variation in how individuals respond to information about their environment, rather than by differences in external factors such as varia...