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November 7, 2008
Even plants benefit from
outsourcing
The answer to successful
revegetation of native flora is in sourcing genetically diverse
seed not necessarily relying on remnant local native vegetation
to provide seed.
“A common belief is that local native plants are the best source
of seed for revegetation projects,” says Dr Linda Broadhurst
from CSIRO, Australia’s
national science agency.
“It has been presumed that local seed is adapted to local
conditions and therefore it would provide the best results for
restoration projects.”
“However, the research shows that where vegetation loss is high
and across large areas, ‘local’ seed sources are often small and
isolated and can be severely inbred resulting in poor seed crops
or low quality seed.”
“This can lead to germination failure and poor seedling growth.”
Land and water degradation resulting from vegetation clearance
is a global problem. Effective restoration techniques are
essential in reducing the damage and improving the environment.
In an effort to help, Dr Broadhurst and her colleagues have
published a review on the issues associated with collecting seed
for broadscale restoration projects in the new journal
Evolutionary
Applications (Volume 1, Issue 4).
The review covers the appropriateness of using ‘local’ seed, how
much seed and the types of populations that should be sampled,
and the impact that over-harvesting might have on remnant
populations.
“The current emphasis on using local seed sources for
revegetation will, in many cases, lead to poor restoration
outcomes,” says Dr Broadhurst.
“Our findings show that seed sourcing should concentrate less on
collecting from local environments and more on capturing high
quality and genetically diverse seed.”
“This will ensure that restored populations have ample genetic
diversity to respond to changing environments over the coming
decades.”
The review, titled ‘Seed supply for broadscale restoration:
maximising evolutionary potential’ is published in Evolutionary
Applications in October 2008. DOI:
10.1111/j.1752-4571.2008.00045.x
Seed supply for
broadscale restoration: maximizing evolutionary potential
Linda M. Broadhurst 1 , Andrew Lowe 2 , David J. Coates 3 ,
Saul A. Cunningham 4 , Maurice McDonald 5 , Peter A. Vesk 6
and Colin Yates 3
1 CSIRO Plant Industry, Canberra, ACT, Australia
2 Ecology & Evolutionary Biology, The University of
Adelaide, Adelaide, SA, Australia
3 Department of Environment and Conservation, Bentley
Delivery Centre, WA, Australia
4 CSIRO Entomology, Canberra, ACT, Australia
5 CSIRO Centre for Environment and Life Sciences, Wembley,
WA, Australia
6 School of Botany, The University of Melbourne,
Parkerville, VIC, Australia
http://www3.interscience.wiley.com/journal/121397345/abstract?CRETRY=1&SRETRY=0
ABSTRACT
Restoring degraded land to combat environmental degradation
requires the collection of vast quantities of germplasm
(seed). Sourcing this material raises questions related to
provenance selection, seed quality and harvest
sustainability. Restoration guidelines strongly recommend
using local sources to maximize local adaptation and prevent
outbreeding depression, but in highly modified landscapes
this restricts collection to small remnants where limited,
poor quality seed is available, and where harvesting impacts
may be high. We review three principles guiding the sourcing
of restoration germplasm: (i) the appropriateness of using
'local' seed, (ii) sample sizes and population
characteristics required to capture sufficient genetic
diversity to establish self-sustaining populations and (iii)
the impact of over-harvesting source populations. We review
these topics by examining current collection guidelines and
the evidence supporting these, then we consider if the
guidelines can be improved and the consequences of not doing
so. We find that the emphasis on local seed sourcing will,
in many cases, lead to poor restoration outcomes,
particularly at broad geographic scales. We suggest that
seed sourcing should concentrate less on local collection
and more on capturing high quality and genetically diverse
seed to maximize the adaptive potential of restoration
efforts to current and future environmental change.
Evolutionary Applications
Online ISSN: 1752-4571
Frequency: Quarterly
Current Volume: 1 / 2008
Edited by:Louis Bernatchez
www.evolutionaryapplications.org
Blackwell Publishing Ltd
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