Sir

In his timely Opinion article on the place of botanic gardens in contemporary society ('Beyond the greenhouse' Nature 455, 596–597; 2008), Mike Maunder notes that gardens are, rightly, “embracing their cultural identity”. But it is not enough simply to celebrate the cultural and natural heritage of a place.

As bodies such as Terralingua and the United Nations Educational, Scientific and Cultural Organization have noted, cultures and languages are becoming as endangered as species and habitats. Superimposing maps of biodiversity hotspots and areas of cultural and linguistic diversity reveals an extensive degree of overlap, implying that similar threats are common to both (see also W. J. Sutherland Nature 423, 276–279; 2003).

As biological diversity is eroded, key elements of cultural traditions, practices and language are lost. Conversely, as cultures and languages are lost, we lose irreplaceable information about the natural world, as well as notions and philosophies of place, time and humanity.

Biological conservation and cultural conservation must therefore be considered simultaneously within a 'biocultural diversity' framework. In fact, I might argue for the primacy of culture in setting conservation priorities.

Many botanical gardens are developing new education, research and collections-based programmes on plant conservation. These can become conservation leaders by explicitly incorporating cultural and linguistic conservation into their programmes and engaging local cultural practitioners.