I examine, through an extensive compilation of published reports, the nature and variability of carbon flow (i.e., primary production, herbivory, detrital production, decomposition, export, and biomass and detrital storage) in a range of aquatic and terrestrial plant communities. Communities composed of more nutritional plants (i.e., higher nutrient concentrations) lose higher percentages of production to herbivores, channel lower percentages as detritus, experience faster decomposition rates, and, as a result, store smaller carbon pools. These results suggest plant palatability as a main limiting factor of consumer metabolical and feeding rates across communities. Hence, across communities, plant nutritional quality may be regarded as a descriptor of the importance of herbivore control on plant biomass (“top‐down” control), the rapidity of nutrient and energy recycling, and the magnitude of carbon storage. These results contribute to an understanding of how much and why the trophic routes of ca...

https://www.jstor.org/stable/10.1086/303244

Patterns in the Fate of Production in Plant Communities.

Seagrass meadows represent a distinct habitat in shallow coastal and estuarine ecosystems. We examine the role of seagrass meadows as an important habitat for fishes and large mobile invertebrates. In particular, we emphasize the importance of the structural complexity of the vegetation and associated algal components. Based on data from a variety of geographical localities we consider how vegetation density, plant morphology and associated sessile colonial animals can influence abundance and diversity of predator and prey species in vegetated areas on both local and regional geographical scales. In so doing we generate hypotheses that lead to predictions concerning: size of populations and the amplitude of their fluctuations in vegetated habitats at different latitudes; success rate of predators using different foraging strategies in vegetation of different densities; and resultant diversity and abundance of invertebrate prey, juvenile fish and adult fish in different densities of vegetation.

Seagrass habitats: the roles of habitat complexity, competition and predation in structuring associated fish and motile macroinvertebrate assemblages

In many coastal locations, seagrass meadows are part of a greater seascape that includes both marine and terrestrial elements, each linked to the other via the foraging patterns of consumers (both predators and herbivores), and the passive drift of seagrass propagules, leaves, roots and rhizomes, and seagrass-associated macroalgal detritus. With seagrasses declining in many regions, the linkages between seagrass meadows and other habitats are being altered and diminished. Thus, it is timely to summarize what is known about the prevalence and magnitude of cross-habitat exchanges of seagrass-derived energy and materials, and to increase awareness of the importance of seagrasses to adjacent and even distant habitats. To do so we examined the literature on the extent and importance of exchanges of biomass between seagrass meadows and other habitats, both in the form of exported seagrass biomass as well as transfers of animal biomass via migration. Data were most abundant for Caribbean coral reefs and Australian beaches, and organisms for which there were quantitative estimates included Caribbean fishes and North American migratory waterfowl. Overall, data from the studies we reviewed clearly showed that seagrass ecosystems provide a large subsidy to both near and distant locations through the export of particulate organic matter and living plant and animal biomass. The consequences of continuing seagrass decline thus extend far beyond the areas where seagrasses grow.

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Trophic Transfers from Seagrass Meadows Subsidize Diverse Marine and Terrestrial Consumers

Behavioural Mechanisms of Food Selection examines animals belonging to diverse trophic groups, from carnivores, herbivores, micro-algal grazers, to filter-feeders and detritus-feeders. In the past Optimal Foraging Theory has been applied to all these groups, but in different ways and in disci plines that rarely overlap. Here concepts and developments hitherto scattered in the literature are drawn together. This uniquely broad synthesis captures the state of the art in the study of diet selection and prescribes new objectives in theoretical development and research.

Behavioural mechanisms of food selection.

Paracentrotus lividus is an incredibly oppommistic generalist, with a very wide range of adaptive responses to environmental conditions. It can do everything and anything. This chapter presents a short overview of the ecology of Paracentrotus lividus. Paracentrotus lividus is a rather large sea urchin that can reach 7.5 cm. In spite of its popular name, the color is highly variable: black–purple, purple, red–brown, dark brown, yellow–brown, light brown or olive green. In the most of its geographical range, either in past or present times and on a regular or occasional basis, its gonads have been appreciated as seafood or it has been intensely harvested. This chapter also gives a deeper understanding of its distribution and habitat, food and feeding, movement and migration, morality, diseases, growth, and reproduction cycles.

Ecology of Paracentrotus lividus

A stand of Posidonia oceanica DELILE at the island of Ischia (Gulf of Naples) was investigated as to its production and the fate of the organic matter produced A site in 4 m depth with a mean leaf biomass of 115 kg dry weight had a net production of 152 gC per square meter and day during the period of May to July 1976 About 50% of this production is consumed in the system, approximately 30% exported continuously The only potential herbivore, the sea urchin Paracentrotus lividus LAM consumes about 9-10% of the net production, but does not attack living Posidonia tissue The hypothesis is presented that there is a strategy to limit direct herbivory on marine macrophytes, which constitutes an energy drain on the primary producer compartment without a feedback reward loop through the products of remineralization as in similar terrestrial ecosystems

Ludwig Maurer

Papers

Strategies of energy transfer from marine macrophytes to consumer levels: the posidonia oceanica example