Evidence regarding import and release of Glomus iranicum var. tenuihypharum Dr Rod Hitchmough Science Advisor, Biosecurity Department Of Conservation
We are accepting the applicant’s information at face value • Effectiveness • Host range • Inoculation techniques, including spray irrigation in situ
We will show that there is good evidence that: • Release of G. iranicum var. tenuihypharum is inconsistent with DOC goals for Biodiversity. • Spread of Glomus iranicum var. tenuihypharum throughout New Zealand is likely. • G. iranicum var. tenuihypharum is likely to colonise weeds and native plants. • G. iranicum var. tenuihypharum is likely to increase weediness and weed control costs.
DOC’s goals for biodiversity DOC’s high -level biodiversity goals, from the 2018 Annual Report: • Indigenous dominance – ecological processes are natural • Species occupancy – the species present are the ones you would expect naturally • Ecosystem representation – the full range of ecosystems is protected somewhere Cf.: EPA Staff Assessment report: “In the event that G. i. var. tenuihypharum spreads beyond the desired target area, it presents an opportunity to improve the environmental conditions and survival of native plants”
G. iranicum var. tenuihypharum is likely to spread • The applicant claims that because this fungus has no aerial spores it will not spread beyond the agricultural areas where it is deliberately introduced • EPA Staff Assessment report: “We evaluated the probability as low as Glomus fungi disperse through the soil slowly and infrequently by soil- disturbing animals and abiotic factors ” • Spread is by ground water and surface water movement and by burrowing animals and in soil carried by other agents such as machinery • DOC believes that lack of aerial spores is no barrier to spread; other soil organisms without aerial dispersal have spread widely and become serious pests
The EPA internal report has misunderstood the reference to kauri die- back in DOC’s submission • Kauri die-back is caused by an oomycete, not a fungus – the two groups are related at least a distantly as plants are to animals • EPA Staff Assessment report: “DOC stated concerns regarding the potential widespread adverse effects of releasing Glomus iranicum var. tenuihypharum into ecosystems by referencing kauri dieback disease which is caused by the microorganism, Phytophthora agathidicida , as an example of a soil microbe that has caused widespread adverse effects on the environment.” • The reference was to kauri die-back as a disease caused by an organism with no aerial dispersal, which is nevertheless being dispersed across the landscape to a degree causing high levels of concern, and the introduction of cleaning stations and closure of tracks – the emphasis was intended to be on dispersal of a soil organism with no aerial spores
G. iranicum var. tenuihypharum is likely to colonise non-target plants. • Proven host range includes species which span almost the entire diversity of flowering plants, including grasses • No cultivated plants have been found to be resistant to colonisation by the fungus • Therefore, there is high likelihood that weeds, non-target cultivated plants and native plants will be colonised where they come into contact with the fungus
Host range (number NZ native species)
We believe this implies considerable impacts on weediness • Weeds are plants with high competitive ability due to vigorous growth and wide ecological tolerance, growing in the wrong place • This fungus increases vigour of growth and tolerance of difficult environmental conditions • This implies it is likely to increase the severity of impact of existing weeds • It also has the potential to create new weeds from previously benign plants, including cultivated and native plants • Pasture grasses are already serious weeds where they’re growing in the wrong place (native ecosystems)
Specific risks from increased salinity tolerance EPA Staff Assessment report: “ G. i. var. tenuihypharum could be used as a tool for conservationists to restore degraded and saline environments, such as coastal sand dunes.” • Incompatible with DOC goals • Weeds are a particularly severe threat in saline ecosystems, where they threaten to smother low-growing native plants • Inland saline ecosystems are among the most severely threatened of all New Zealand ecosystems and among the hardest to protect because of the influence of surrounding land use • Pasture grasses are amongst the most severe environmental weeds in these systems • This fungus was isolated from saline ecosystems which are its native habitat in Spain • The impacts via increased weediness, particularly of pasture grasses, are likely to be particularly severe, and to threaten both these ecosystems/plant communities and individual plant species found only in these particular ecosystems with extinction
Impacts on conservation values of increased weediness • EPA Staff Assessment report : “any potential benefits to invasive plant species through uptake of nutrients could also have beneficial effects to native plant species outside the targeted areas. We concluded that the consequences of any risks of displacing native AMF or enhancing the fitness of invasive or exotic plants would be minimal to minor and the effects of those effects would be negligible to low on the environment.” • Totally incompatible with many past examples of introduced species destabilising rather than assisting native systems • This assumes that the system is in balance now, whereas weeds invade native systems already and weeds directly threaten some native plants. • Some weeds have competitive advantages because of attributes such as growth form; many pasture grasses for example spread by stolons, whereas native grasses form tussocks which do not spread vegetatively
Greater vigour of exotic plants will increase weed numbers and control costs • Currently >400 weed species are controlled on public conservation land • More exotic plants (>2,500) are growing wild than native plants. • At least $12 million p.a. spent by DOC on weed control • Private landowners, councils and community groups also spend very significant amounts of time and $$
Conclusion • Contrary to statements by the applicants, the fungus could be spread by animals, people, machinery and water movement • DOC totally rejects any idea that invasion by this fungus could benefit native ecosystems and species • DOC believes this endophyte fungus could colonise many weed species, thereby increasing their vigour and ecological impact • It could also tip currently benign plants into becoming serious weeds • DOC already spends >12 million on weed control in natural ecosystems and at restoration sites; councils and community groups also spend very significant amounts of time and $$
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