Tagging and transects

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    Jacqui
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    If we are to conserve species effectively, it is vital we monitor how they are faring. The status of our wildlife depends on the effects of climate change, pollution, alien species and land management. Reliable data on trends in the abundance and distribution of our flora and fauna is vital for predicting the impacts of such change, and for developing an appropriate response.

    Butterflies are uniquely placed to act as indicators of the state of the environment.

    Life as we know it wouldn’t exist if we didn’t have pollination – and butterflies are key pollinators.. Butterflies are highly admired and valued by people – and yet there is little research being done into if (and why) their numbers are diminishing in New Zealand. Overseas countries have learned the hard way – it is not too late for NZ to undertake research into this beautiful species of insect life.

    Unless we have an idea of what is there, and where it is, and how to identify it, we can’t take care of it properly. When we know what is there, we can go back and keep checking against that record to see what is changing. We can see the costs in biodiversity of a certain practice, and how to mitigate those.

    But first we need some basic information.

    Members, non-members are welcome. We would also like to involve schools and home-schooled children in these projects.

    Butterfly transects

    This part of the project will involve people walking a set route, each week on warm, dry, sunny days between October and March, in locations that they choose – they can be adjacent to their home. At the same time they will record what butterflies they observe. Undertaken over a series of years this will give information as to seasonal populations of all butterflies in NZ, and reliable data as to whether populations are increasing or decreasing, as well as local trends and national patterns.

    Walkers imagine that they have a ‘box’, 2.5 metres on each side and 5 metres in front of them, and they note down the name of any butterflies that they see in that space as they walk.

    Butterfly transects were devised in 1973 by the Centre of Ecology & Hydrology in the UK. According to the CEH, the information gained from transect monitoring is invaluable, especially if the same transect is walked for many years. Regional and national indices are generated, and early warnings generated of species’ decline, at a time when conservation action can be most effective and before species are lost from whole sites and areas.

    Transects not only provide accurate assessments of how each species of butterfly is doing every year, but answers many questions about butterfly ecology and how habitat management and the weather affect populations. With today’s advantage of digital photography it will also be possible for walkers to capture pictures of specimens they cannot identify – and thus be able to record previously unidentified arrivals in NZ.

    Entomologist Brian Patrick, formerly with Otago Museum says that NZ’s invertebrate fauna is more special than we think.

    “If you look at the insect fauna of the UK, it is shared with the rest of Europe. In contrast, our insect fauna is largely peculiar to NZ. We have a responsibility to look after an invertebrate fauna that occurs nowhere else,??? he said. “Introduced invertebrates ‘pollute and dilute’ the native fauna much like weeds do in a forest.???

    He warns: “Every time we modify an ecosystem, the new animals we have introduced are sitting there waiting – cockroaches, slaters, spiders and earwigs – and they take the opportunity to quickly invade the modified ecosystem we have created.???

    Brian has agreed to work with the Trust to ensure that this project achieves measurable outcomes.

    Tagging Monarch Butterflies (Danaus plexippus plexippus)

    In the late 1960s Auckland Museum entomologist Keith Wise undertook tagging and his findings were reported in 1980 (Rec Auckland Inst Mus 17: 157-173, 17 December 1980), This would give us the opportunity to learn about their longevity and dispersal in NZ, overwintering habits etc.

    At that time, he stated “…the project did not produce the information sought on dispersal of Monarch butterflies…??? and that “…no large scale migrations or movements were detected by tagging.???

    “The project, had in the main, established that large numbers of Monarch butterflies in the North Island stayed in their home areas both in summer and winter periods, although a small number did make long flights. At the same time the presence of known overwintering colonies was confirmed, particularly one at Tauranga Bay in the far north, but no movements into or out of these were recorded.???

    While thousands of Monarchs were found to be overwintering at Tauranga Bay in the 1980s, by winter 2005 when entomologist Peter Maddison surveyed the area, a maximum of twenty were there. What has happened to them?

    We will repeat the 1960-70 tagging exercise, using more sophisticated methods than were available then. Keith Wise has indicated he is willing to be involved in this project.

    If you would like to be involved in this project, please register now:

    https://www.monarch.org.nz/ecology/tagging-transects/

    Thanks!

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