Wednesday, 16 October 2013

Local seeds vital for effective banksia restoration

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firewoodbanksiaScientists analysed the spatial genetic structure from across the range of 24 Banksia menziesii populations. Image: SydneydawgBOTANISTS are analysing spatial genetic structure within keystone species, to enable better seed sourcing for banksia woodland restoration programs.   

Banksia trees and shrubs are widely distributed throughout southern Western Australia and are significant for ecological restoration.

Kings Park and Botanic Gardens senior researcher Siegy Krauss says the sourcing of seed is a major issue that can significantly impact on restoration success.

“Best practise emphasises the use of local seed but restoration practitioners ask, how local is local?” Dr Krauss says.

The research by the University of Western Australia and Botanic Gardens & Parks Authority has, through analysing the genetic structure of firewood banksia (Banksia menziesii), found that ‘local’ populations can be identified within a 30km radius.

“Beyond a 30km radius pairs of populations were on average more than twice as diverged as those within 30km,” Dr Krauss says. 

Scientists analysed the spatial genetic structure from across the range of 24 Banksia menziesii populations.

Molecular markers were used to genotype individual trees, establishing the spatial genetic variation of the species and quantifying the relationship between genetic and geographic distance.

This was done using the DNA fingerprinting technique; amplified fragment length polymorphism.

“By genotyping plants and understanding the scale of the local genetic provenance, botanists can inform restoration practitioners on the source of local provenance seed,” Dr Krauss says.

Collecting and storing seeds from the most suitable geographic range gives plants a home site advantage and minimises negative impacts in ecological restoration programs.

“The introduction of non-local provenance genotypes can swamp local genotypes and erode natural patterns of spatial genetic structure within species, resulting in a loss of biodiversity,” Dr Krauss says.

“For example, introduced Geraldton wax into Perth’s Bold Park has threatened to swamp the locally significant southern variety, Wembley wax.

“Even though they are the same species, the non-local provenance Geraldton wax is in this instance regarded as a weed and managed as such.”

Local provenance seed is especially significant on larger restoration scales such as reclaiming mining areas, where use of inferior seed can have cost and restoration impacts.

“For large scale restoration seed banks are increasingly important,” Dr Krauss says.

By stockpiling and tracking the genetic provenance of local species, botanists can maintain the correct plant diversity, control competitor species and produce a highly functioning and resilient biological system.

“New Next Generation Sequencing technology will soon enable population genomics research and a much more powerful assessment of population genetic variation of significance for seed sourcing decisions and better restoration outcomes,” Dr Krauss says.

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