Why eco-sourcing makes sense
The enthusiasm Kiwis have for restoring native vegetation is growing, as we face a problematic environmental future.
Native planting projects are constantly being initiated and developed, especially around rivers and streams. However, it is important to consider the source of the plants being used.
For most species, ecologists have no idea of the appropriate size of the area to source from - is it an island, an ecological district, or much smaller - as in the size of a sports field? Why is this important? Plants (and animals too) vary genetically from place to place, and a genotype that functions well in one place, may not function well in another. It may be unable to reproduce, or to interact normally with the other members of the vegetation.
Few Manawatu plant nurseries grow eco-sourced material suitable for the different parts of our region. Instead, projects need to set up a seed collection and growing system for themselves so they can use the nearest appropriate plants to provide seed or seedlings for each location.
For example, along the Kahuterawa Stream, restoration planting run by Linton Army Camp, Horizons and Massey University, only uses material sourced from within the planting zone itself where possible. Because it is a long thread of stream with several remnant stands of native vegetation, we are able, for some species, to source at an even finer scale.
In the future, ecologists will be able to study how much this matters. Information about eco-sourcing can be found at the NZ Plant Conservation Network website, www.nzpcn.org.nz.
Using non-eco-sourced plants could be an ecological disaster in waiting. Some argue that planting non-eco-sourced material will improve the vegetation’s responsiveness to climate change.
However, the effects of climate change are hard to predict, so we don’t know whether to use species from warmer areas, from wetter or seasonally dry areas, from similar vegetation types to ours, or from different ones.
Species will not all respond in the same way to climate change anyhow. It seems best to leave nature to make the decisions about managing that aspect of our ecosystems. At least for now, local is best.
Plants for the Kahuterawa Stream.