Date of Award

Winter 1982

Project Type


Program or Major


Degree Name

Doctor of Philosophy


During 1979-1982 I investigated aspects of the ecology of Herring Gull (Larus argentatus) and Great Black-backed Gull (Larus marinus), Harbor seal (Phoca vitulina), and rodent (Rattus norwegicus, Cricetus aurata, Mus musculus) carrion communities on the Isles of Shoals, a group of nine small islands located 10 km SW of Portsmouth, New Hampshire (42(DEGREES)59'N, 70(DEGREES)37'W).

Carcasses passed through a series of predictable decompositional stages (fresh, bloat, active, advanced, and dry) defined by characteristics of carrion appearance and faunal associates.

Of the numerous species of invertebrates collected from coastal carrion, few played a major role in decomposition. Blow fly larvae and dermestid beetles were the primary carrion consumers. Spiders, ants, and staphylinid and histerid beetles were the major predators. The importance of carrion frequenting insects in the decomposition of vertebrate carrion located in habitats with strong maritime influences was indicated.

Carrion community members were divided into 5 tropic guilds: (i) Necrophages, (ii) Necrophiles, (iii) Predators, (iv) Necrophages/Predators, (v) Parasites. Necrophages partition carrion spatially, temporally, and by extent of desiccation. Predators selected prey by location, size, and life stage. Carcasses located in "less exposed" areas characteristically supported a greater variety of species and decomposed at a slower rate. Seasonal variations in carrion abundance, availability to necrophagous arthropods, and community composition were evident on the Isles of Shoals.

Small carcasses supported statistically fewer anthropod species than large; and carrion located at greater distances from source of colonists were also less species rich. The successional process, characteristics of early and late colonists, and the effects of carrion size and distance from source of colonists suggest a process of colonization and community development consistent with geographical and less ephemeral biological island systems.