The 1973 Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) restricts trade in endangered organisms, and the word among scientific collectors is that it restricts their research as well. A paper now illustrates this 'CITES effect' in hard numbers (D. L. Roberts and A. R. Solow Proc. R. Soc. B doi:10.1098/rspb.2007.1683 ; 2008).

Botanical gardens are shying away from orchids. Credit: P. CRIBB

David Roberts of the Royal Botanic Gardens in Kew, UK, and Andrew Solow of the Woods Hole Oceanographic Institution in Massachusetts, compared the rate at which two botanical gardens in the United States collected two kinds of plant: orchids, many of which are covered by CITES, and bromeliads, of which very few are. They found that before the convention was ratified, the institutions were collecting three orchids for every bromeliad, but after this time the ratio fell to just 1:1.