Separating the effects of habitat loss and habitat fragmentation is difficult. To solve this problem, Mary Bonin and her colleagues at James Cook University in Townsville, Australia, arranged a series of experimental reefs off Papua New Guinea.

Few damselfish survived on reefs of Acropora subglabra (pictured) from which 75% of coral had been removed, whereas those on reefs that had been broken up but maintained in area actually did better than those on untouched control reefs. Species richness and abundance were also higher on fragmented reefs than on those that had lost habitat. Although the positive effect of fragmentation declined over a 16-week period, the impact of habitat loss worsened in this time, suggesting that reported declines in fish populations after habitat disruption are down to the latter and not the former.

Credit: D. B. FLEETHAM/PHOTOLIBRARY.COM

Ecology doi:10.1890/10-0627.1 (2011)