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Comparison of management strategies for controlling N assella trichotoma in modified tussock grasslands in N ew Z ealand: a spatial and economic analysis
The weedy grass Nassella trichotoma (nassella tussock), historically an economically damaging invader of modified tussock grasslands in New Zealand, currently causes little if any reduction in farm production. This is a result of successful historical regional management programmes in which plants h...
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Published in: | Weed research 2015-10, Vol.55 (5), p.449-460 |
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Main Authors: | , , , |
Format: | Article |
Language: | English |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The weedy grass
Nassella trichotoma
(nassella tussock), historically an economically damaging invader of modified tussock grasslands in New Zealand, currently causes little if any reduction in farm production. This is a result of successful historical regional management programmes in which plants have been removed manually (by grubbing) each year before they seed. To inform a debate about the need for ongoing regional management, we developed a stage‐structured spatially explicit integrodifference equation population model and linked this to a cost analysis. We used the model to compare the weed's future population trajectories and related regional control costs over 50 years under three alternative management scenarios. The total discounted (3% p.a.) costs of
no management
,
three‐yearly grubbing
and continued
annual grubbing
were
NZ
$417 million, $736 million and $131 million respectively. These analyses indicate that annual grubbing of
N. trichotoma
returns a net benefit of $286 million ($417 – $131 million) compared with doing nothing and a net benefit of $605 million ($736 – $131 million) compared with a 3‐yearly grubbing programme. These results support the continuation of
annual grubbing
as the long‐term economically optimal management strategy for
N. trichotoma
on pastoral farms infested by the weed in New Zealand. |
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ISSN: | 0043-1737 1365-3180 |
DOI: | 10.1111/wre.12158 |