By Simone Pedrini, Curtin University, Perth, Western Australia
We all know that native seeds for restoration can be quite expensive. But how much exactly?
A recent study, published in the Journal Restoration Ecology, analysed the seed price for 129 species commonly used in mine site restoration in South-Western Australia. The average price per kg of seed is on average $ AUD 1,093. However, this value does not consider if the seeds are alive and in what percentage. By testing the quality of seed and adjusting the price for viability, the average cost for a kg of Pure Live Seeds is more than doubled, at $ AUD 2,600.
Purity and viability testing. (A) Subsample of Eucalyptus rudis as extracted from the seed batch, (B) separated fractions of non-seed material (left) and pure seed units (right) from the same subsample of Eucalyptus rudis. By weighing each fraction, it is possible to estimate the PSU%. (C) X-ray image of Acacia saligna where it is possible to differentiate between seeds that appear healthy to seeds that are shriveled or have evidence of predation. (D) Form used to collect data on seed quality. This form is a simplified version of the proforma presented in the International Principles and Standards for Native Seeds in Ecological Restoration. The viability/fill data are presented in rows 1–5, the number on the left (f) is the number of filled seeds, the one on the right (e) is the number of seed considered non-viable because empty, predated, broken, or shriveled. Totals and averages are automatically calculated in the database. In the test field, it is specified which viability test was performed (X-ray, cut test, germination). In this case, all of the tests performed done via X-ray. (E) Label printed from the seed quality database reporting the key results of the quality test: PSU% and PLS%
This study highlights the importance of native seed quality testing for correctly estimating (and budgeting) seed procurement for restoration projects.
Moreover, we suggest moving away from the current method of selling native seed on a weight basis (kg or lb), as it does not provide any information about seed quality or seed size (which vary greatly among species).
Instead, we propose a new, more transparent method for pricing native seeds based on the cost of a thousand pure live seeds ($ TPLS). We posit that this new way of pricing native seeds would increase transparency and information flow in the marketing of native seeds, enabling seed users to more reliably plan for, and evaluate the cost-effectiveness of seed-based restoration projects.
In this short presentation, we explain how $ TPLS can be calculated using the information obtained during the seed quality testing.
For more information, you can access the full open-source directly from the Restoration Ecology Website: https://onlinelibrary.wiley.com/doi/full/10.1111/rec.13638