Repetitive harvesting of Macrocystis pyrifera (Phaeophyceae) and its effects on chemical constituents of economic value

Kelp harvesting has increased globally in recent decades and is expected to continue rising as the demand for kelp-derived products for use in aquaculture and industrial applications increases. In response, numerous studies have examined how harvesting impacts kelp populations and their associated communities, but the effects of repeated harvesting of the same individuals on the chemical properties for which they are extracted remain poorly understood. This knowledge gap may be especially crucial in areas where the same kelps are necessarily harvested multiple times per year due to their overall low abundance. To address this, we examined how repetitive harvesting of the same individuals of giant kelp,

Breeding habitat selection in an obligate beach bird: a test of the food resource hypothesis

The food resource hypothesis of breeding habitat selection in beach-nesting birds suggests that birds breed at sites with more prey to meet the increased energetic requirements associated with breeding. We compare prey resources using pitfall traps and core samples at breeding sites and absence sites of the eastern population of hooded plover, Thinornis rubricollis rubricollis, which, in this part of its range, is a threatened obligate beach bird. Breeding sites had higher abundances, equivalent species richness, and different assemblages of invertebrate prey compared with absence sites. Assemblages at breeding sites were characterised by more isopods, and fewer beetles of the family Phycosecidae. Breeding habitat selection by plovers appears to be associated with selection for sites with more food, and any process that degrades food resources at a site (e.g. kelp harvesting or marine pollution events) may reduce the likelihood of occupancy of that site by breeding birds.