Impact 2 - Management
Kate Ladley teaching survey techniques to DOC Southland Tier 1 team. Image - Em Oyston, DOC
Frameworks are in place to ensure the most threatened ecosystems, habitats and species are managed to reduce the risk of decline in native biodiversity.
Rocky outcrop ecosystems on Banks Peninsula
The rocky outcrops on Banks Peninsula are a naturally uncommon ecosystem. This year the Banks Peninsula Conservation Trust and QEII ran a rocky-outcrops field day for 90 landowners and we delivered the keynote address. Ongoing work with these two agencies, Christchurch City Council and ECan has led to targeted weed and pest control efforts to ensure the perpetuation of threatened biota and associated unique ecosystems. The upsurge of official interest has been matched by private landowners covenanting rocky outcrops.
Our field research showed that the volcanic rocky outcrops on Banks Peninsula support 350 vascular plants; thus more than a third of the Peninsula’s flora occurs on 5% of the landscape. Some 63 species are found only on outcrops, and many are rare, including 4 of the 8 taxa endemic to Banks Peninsula. Although the community appreciated the striking visual impact of these outcrops, there had previously been limited awareness of their importance for biodiversity.
This research is part of the Managing Biodiversity portfolio. Ongoing interaction with the groups mentioned is supported by Core funding.
Ecosystem risk assessments
The International Union for Conservation of Nature (IUCN) has traditionally focused on identifying the world’s most threatened species. The IUCN has now proposed a new quantitative approach to assessing risk to ecosystems, based on changes in the extent of ecosystems, environmental degradation, and disruption of biotic processes. In recognition of our work last year in undertaking a threat assessment of New Zealand’s 72 naturally uncommon ecosystems, Landcare Research was invited to join a high-profile international working group developing the IUCN Ecosystems Red-List protocol.
The IUCN criteria assess four distributional and functional symptoms of ecosystem decline: (1) decline in ecosystem distribution; (2) restricted distributions with continuing declines or threats; (3) environmental (abiotic) degradation; and (4) disruption to biotic processes. A fifth criterion (quantitative estimates of the risk of ecosystem collapse) enables integrated assessment of multiple processes and provides a conceptual anchor for the other criteria.
A trial of the protocol on terrestrial, subterranean, freshwater and marine ecosystems from around the world shows that its concepts are workable and its outcomes are robust, that required data are available, and those results are consistent with assessments carried out by local experts and authorities. The new protocol provides a consistent, practical and theoretically grounded framework for establishing a systematic Red List of the world’s ecosystems. This will complement the Red List of species and strengthen global capacity to report on and monitor the status of biodiversity.
This research is part of the Managing Biodiversity portfolio and was supported by Core funding. The IUCN Working Group workshops have been supported by the Australian Centre of Excellence for Environmental Decisions and the Australian Centre for Ecological Analysis and Synthesis.
Pest control to improve tree survival
A new, user-friendly model to help target herbivore control has been developed. The model was developed for DOC to predict the level of herbivore control required to increase tree survival to acceptable levels and provide quantitative estimates of the benefits for forest health of current herbivore management strategies at specific sites. The model will enable DOC and AHB (now TBfree New Zealand) to prioritise possum control at local and regional scales to protect tree species at risk of mortality.
This research is part of the Managing Invasive Weeds, Pests and Diseases portfolio, and was supported by DOC funding.
Effectiveness of regional councils’ pest management
Regional councils spend over $41 million per year (2008 estimate) in managing weed and animal pests. This is a substantial sum so councils need better means of demonstrating that this expenditure is achieving the Long Term Council Community Plan (LTCCP) outcomes and represents good value to the community.
We held workshops with 12 regional and district councils to help biosecurity staff specify the desired outcomes from their pest management programmes and identify appropriate performance indicators and reporting mechanisms. We produced an online resource package that councils and other groups can use to maintain capability in this area. Uptake by councils has been significant: nine have already incorporated the principles in their pest management planning and the remainder intend to do so as appropriate to their reporting and review schedules.
This research is part of the Managing Invasive Weeds, Pests and Diseases portfolio, and was supported by Envirolink funding.
Best practice in monitoring bird abundance
Landcare Research led an authoritative overview, with DOC and other agencies, of best practice and techniques for measuring abundance, occupancy and distribution of forest birds for national ‘state of the DOC environment’ monitoring. A pilot study measuring assemblages of widespread and common bird species at the national scale found that spatial variability in the landscape was a major factor influencing detection, an issue often overlooked when estimating bird population trends through time. Most endemic birds (i.e. those found only in New Zealand) were detected in forest, while most native and introduced species were detected in shrubland.
We used a monitoring study of bellbirds in Christchurch to gain greater understanding of issues affecting biodiversity in an urban situation. We can now offer advice and guidance on best practice for such monitoring schemes and how to modify green spaces to enhance urban bellbirds.
Two other studies showed that Australian magpies are not displacing native birds in rural landscapes. Magpies were continuously removed from five 900-ha sites for 3 years in one study and from individual farm gardens over a 6-week period in another, with no magpies removed in matched non-treatment sites. The studies indicated magpies had little impact on native birds, a finding that has application for restoration ecology, conservation management, and biodiversity management on private land.
This research is part of the Managing Biodiversity portfolio. The projects were supported by ARGOS and Core funding, MBIE contestable funding, and Northland, Auckland, Waikato, Bay of Plenty, Hawke’s Bay, Wellington, Marlborough, Canterbury and Southland regional councils.
Predicting mast seeding for strategic predator control
Mast seeding is the occasional production of unusually high quantities of seed that occurs in some plants, such as beech trees. Masting events lead to irruptions in populations of seed consumers (mice and rats) followed by increased predator populations (e.g. stoats) that also prey on native birds and insects as well as rodents.
The theory that masting is triggered by warm temperatures the previous summer has been updated – with a new twist. With the University of Canterbury, we analysed 26 long-term New Zealand datasets spanning 15 diverse plant species, and 20 of the longest-running Northern Hemisphere datasets covering 17 species from North America, Japan and Europe. A wide range of mast-seeding species respond to the difference in temperature from one growing season to the next, i.e. the change in mean summer temperature between the two preceding years. This temperature-difference model is also a much better predictor of the rare phenomenon of consecutive high-seed events (double masts).
As well as being of international significance, the new model is of considerable importance to DOC as it more reliably predicts masting events more than a year in advance giving conservation managers time to plan and budget for pest control operations.
This research is part of the Managing Invasive Weeds, Pests and Diseases portfolio, and was supported by Core funding and MBIE contestable funding.
Invasive paper wasps
In New Zealand, two species of invasive paper wasps (Polistes) are a significant nuisance to humans, giving painful stings. Often their nests are found in residential gardens. Paper wasps are also voracious predators of native caterpillars and compete for nectar resources with native insects and birds. Currently, paper wasps are mostly found in the upper North Island, with limited distribution in the Hawke’s Bay, Wellington, and top of the South Island. They have now established in Christchurch and Alexandra, and are likely to spread further in the next few decades.
We combined specimen data from museums and our collections, public survey and previous information to model the extent of the wasps’ likely distribution in New Zealand. We then integrated this information with knowledge on nest density and prey consumption to estimate the extent of biodiversity losses from different regions. We believe that paper wasp impacts in southern latitudes will be confined to a very short ‘summer’ period. Native insects that occupy grasslands and shrublands will consequently face additional predation risk.
This research is part of both the Managing Invasive Weeds, Pests and Diseases and Defining Land Biota portfolios, and was Core funded.
Chemical pollutants found in wildlife
Some chemicals used for pest control, crop protection or in manufacturing have the potential to become persistent organic pollutants’ (POPs) in the wider environment; at sufficient concentrations they may harm human health. Wildlife can act as sentinels for the presence of such contaminants, especially those that persist through the food chain. We tested fat samples from road-killed Australasian harriers, a native bird of prey. A variety of POPs were detected, mostly in relatively low concentrations. Potentially significant levels of compounds used as flame retardants were found as well as DDE, a metabolite of the organochlorine insecticide DDT. Liver samples from harriers and little blue penguins showed that some of the birds of both species had been exposed to anticoagulant rodenticides that are widely available ‘off the shelf’ in New Zealand. The long-term effects of such exposure are not known but urgently need further investigation given the continued use and apparently widespread environmental transfer of these rodenticides.
The Ministry for the Environment (MfE) monitors some POPs in humans, land and water; MPI monitors food for a range of chemical contaminants. Currently POPs and pesticide residues in wildlife, such as birds of prey, are not routinely monitored in New Zealand (as they are in the UK and some other countries). We will use these initial findings to help develop a national wildlife monitoring framework and to characterise contaminants that are known, emerging and potential threats to New Zealand biota and human health.
This research is part of the Managing Invasive Weeds, Pests and Diseases portfolio. The investigations were funded from various sources including Core funding and MBIE contestable funding.
Biological control of heather
Heather (Calluna vulgaris) is a seriously invasive weed in the central North Island. The NZ Army supports our biocontrol programme but has also aerially applied the herbicide Pasture Kleen® (2,4-D ester). We compared the effectiveness and impacts of biocontrol with the army’s use of herbicide.
Results showed that invading heather can be suppressed by either herbicide or heather beetle. Removal of heather by either method does lead to some invasion by exotic grasses, but we expect this will be short-lived. Herbicide application resulted in major non-target damage to broadleaved native plants. In contrast, there was no non-target damage from biocontrol, and the cover of native shrubs increased 4 years after the heather beetle had destroyed the weed. Also, once herbicide treatments ceased, heather reinvaded so repeat treatments would be needed in the absence of biological control.
This work provided DOC and the NZ Army with clear evidence that their long-term support for our heather biocontrol programme is justified, with clear benefits to indigenous biodiversity (compared to the previous use of herbicides).
This research is part of the Managing Invasive Weeds, Pests and Diseases portfolio, and was supported by Core funding, DOC and the NZ Army.