Drylands

Pistacia atlantica, male tree growing in Jordan.

At present, the Millennium Seed Bank Project has focussed its collecting priorities on the arid and semi-arid regions of the world. This is because nearly a fifth of the world's human populations live in such dry lands and are directly dependent upon the plants that grow there.

Dry land vegetation is threatened by human pressures exacerbated by drought. In the long term climate change may increase the impact of such droughts on the natural and human populations. Many dry land plant populations and the genetic diversity that they represent may only be saved by off-site conservation measures such as seed banking. Not surprisingly, many dry land species produce desiccation-tolerant or orthodox seed that can be banked. The seasonal nature of the vegetation and the accessible nature of the fruits make collecting a relatively straightforward procedure. This contrasts to the situation in wet tropical forests where fruits are often produced high up in the canopy and over much longer periods by species that may be thinly scattered over huge inaccessible areas. Furthermore, a higher proportion of the seeds produced will be desiccation intolerant or recalcitrant. The collecting logistics and research support anticipated for seed banking from wet tropical forests make it a less cost-effective tool for conservation of biological diversity, and for such forests habitat protection measures are especially urgent.