Abrupt transitions between macrobenthic faunal assemblages across seagrass bed margins

The nature of the transition from one contrasting macrobenthic assemblage to another across interfaces between intertidal seagrass and unvegetated sand was investigated in the subtropical Moreton Bay Marine Park, eastern Australia, via six two-dimensional core lattices. The same pattern of transition was manifested in each lattice. Macrofaunal abundance, species density (both observed and estimated total) and assemblage composition did not vary with distance away from the interface within the 0.75 m wide marginal bands of each habitat type. Neither were there significant differences in assemblage metrics or composition between the marginal and non-edge regions of either habitat. There were, however, very marked differences in assemblage composition, abundance and species density across the 25 cm wide strip on either side of the actual interface, the interacting assemblages reacting symmetrically. All these differences therefore took place over an ecotone distance of only 0.5 m at most. Spatial trends in assemblage metrics across the boundary zone were captured accurately by second and third order polynomial regression models. It also appeared that edge effects on individual species within the seagrass were a variable local response not a consistent effect of closeness to the bare sand

Individual variation in osmotic pressure of an ocypodid crab

1. 1. Determinations of the blood osmotic pressure of large numbers of apparently "identical" specimens of an ocypodid crab revealed a high level of individual variability. 2. 2. This variability is suggested to have ecological and evolutionary significance

Relative carapace and chela Proportions in some Ocypodid crabs (Brachyura, Ocypodidae)

Die Veränderungen von 4 relativen Carapax- und Chela-Maßen bei zunehmender Größe wurden an 13 species der genera Macrophthalmus, Australoplax, Cleistostoma und Paracleistostoma aus Australasien beschrieben. Die Schlußfolgerung wird gezogen, daß die bisherige Praxis der Einbeziehung einzelner Werte von relativen Größenverhältnissen bei der Beschreibung von Arten der Macrophthalminae ohne Bezug auf die Veränderung während der Entwickelung nur geringe oder gar keine Gültigkeit hat

Fundamentals of Aquatic Ecology

vii,270 hal,;ill,;25 c

An Introduction to Marine Ecology

x,351 hal,;ill,;21 c

An introduction to marine ecology, 2nd Ed.

Indeks Bibl. : 322-331ix, 351 hlm. : il. ; 23 cm