Category: Forests & trees

A new paper out in Biodiversity and Conservation presents a review of how smallholder agroforestry contributes to the conservation of tropical tree species. ((Dawson, I., Guariguata, M., Loo, J., Weber, J., Lengkeek, A., Bush, D., Cornelius, J., Guarino, L., Kindt, R., Orwa, C., Russell, J., & Jamnadass, R. (2013). What is the relevance of smallholders’ agroforestry systems for conserving tropical tree species and genetic diversity in circa situm, in situ and ex situ settings? A review Biodiversity and Conservation, 22 (2), 301-324 DOI: 10.1007/s10531-012-0429-5)) That can seem a funny way to look at it, I admit that even as a co-author. The more obvious question might have been to ask how tree conservation efforts can contribute to smallholder agroforestry, and that has indeed been covered in another paper by some of the same authors. What we were at least partly trying to do in this paper is to make the point to the more general tropical biodiversity community that farmers and cultivated landscapes potentially have a role in conservation.

Potentially being the operative word. Because it’s not automatic. In particular, the paper highlights three areas where we need to do some more work in order to make sure that the potential is realized.

1. Although agroforestry systems can be highly diverse in tree species, this may be transitory, for example as remnant forest trees in farmland die. We need to know how to promote connectivity among low density trees in agroforestry systems in order to support conservation in farm landscapes.

2. Tree cultivation in agroforestry systems (or in plantations) may well support the conservation of nearby trees in natural forest by taking pressure off the resource base, as the conventional wisdom has it. But it may not. In fact, we know little about the link between the two, and there are reasons to think this link is often negative rather than positive for conservation.

3. Ex situ seed storage may not be much of an option for trees because of the high costs of regeneration of stored seed. Do ex situ genebanks lead to a false sense of security about what is conserved? What sorts of partnerships are necessary for genebanks to really come through?

Funnily enough, another paper just out reviews the conservation and use of a particular tropical agroforestry tree, Bactris gasipaes, or the Peach palm. ((Graefe, S., Dufour, D., Zonneveld, M., Rodriguez, F., & Gonzalez, A. (2012). Peach palm (Bactris gasipaes) in tropical Latin America: implications for biodiversity conservation, natural resource management and human nutrition Biodiversity and Conservation, 22 (2), 269-300 DOI: 10.1007/s10531-012-0402-3)) The authors recommend smaller, more carefully chosen and better characterized ex situ collections, which fits in with the third point. ((Incidentally, the paper provides a useful lists of Bactris collections, but only for the Amazon. There are others.)) But not only:

On-farm conservation could be an appropriate alternative for in situ conservation of wild populations, particularly if high levels of diversity are maintained in nearby cultivated populations and these are genetically close to wild populations (Hollingsworth et al. 2005).

As the two previous points suggest, that “could” will need to be deconstructed a bit if a truly effective conservation strategy is to emerge.

But the paper doesn’t stop there. I was particularly interested in the observations that processing and value addition are “virtually non-existent,” and that “40-50% of peach palm production never reaches the market and is either fed to farm animals or wasted.” Plenty of scope for conservation of this particular agroforestry species to contribute to smallholder systems, and perhaps vice versa.