We encourage NatureWatch NZ users to tread lightly on nature. Taking photographs and making sound recordings are great ways to observe species. Collecting specimens is best left to the experts in most cases.
Before biodiversity experts, like taxonomists, collect any species from Department of Conservation (DOC) reserves, including all national parks, they first need a collection permit from DOC. The same applies for collecting any species from anywhere, including private land, that's listed on New Zealand's Wildlife Act. That includes all indigenous vertebrates (birds, lizards, frogs, bats, marine mammals) and many of our most at-risk invertebrates (like giant weta).
Everyone needs a DOC permit before collecting any of these species. Getting a permit requires convincing DOC experts of the scientific or conservation importance of making a collection and that it will be done in an ethical way. Consultation with local iwi is also an essential requirement of the permitting process. There are strict penalties for collecting species from places like national parks without a permit.
Sometimes people on NatureWatch NZ make spectacular discoveries. If you're lucky enough to find something new and exciting in a conservation reserve that needs to be collected for a museum, the experts on NatureWatch NZ can advise you on how best to do it. For example, you can work with them to collect a specimen for their museum using their permit. That process begins with you loading a photo and/or sound recording up to NatureWatch NZ for ID, and an expert letting you know that you've made a significant find.
So, when you're out in New Zealand's nature reserves, stick with photos and/or sound recordings.
In this age of cheap high quality digital cameras and modern taxonomy, you might thing that collecting specimens is no longer important. That's not true at all. Most New Zealand species are still not described by science and collected specimens are an essential part of the taxonomic work that describes new species. Specimens also contain DNA and other chemistry that fuels taxonomic and biochemical research. New Zealand's museum collections of species are as valuable as they have ever been. If anything, they're more important now because DNA technology is becoming cheaper and more powerful.
If you want to take your nature watching beyond photos and sounds, that's great. For example, it's often helpful, and really interesting, to put a caterpillar in a bag with its host plant and watch it grow up to emerge as an adult moth or butterfly. Adult moths are usually much easier to identify than caterpillars. You can then photograph and release the moth, but only if you reared it near where you collected it. You may also want to learn how to properly kill and mount a moth on a pin for a museum collection.
A lot of NZ's experts started out as young amateurs making their own plant, insect, or fungi collections and carefully identifying the things they collected. Some species need careful microscopic examination or dissection to get identified to species. New technology is also making DNA barcoding available for everyone to use to ID species that are tricky to ID from photos (e.g., lifescanner). If you're an expert in training, making your own collection teaches you a lot of useful skills.
You can make collections of exotic species and any non-threatened indigenous species not listed on the Wildlife Act as long as they're not collected on conservation land. Picking a mushroom or a small lateral branch of a plant for a collection does minimal harm to the organism (picking a mushroom is like picking an apple from an apple tree). Most invertebrates are so numerous, and natural predation so common, that losing a few extra individuals to a collection makes no difference to the populations. If you are killing things, like insects, please ensure that this is done in a humane way (e.g., kill them in the freezer) and only kill them when you have a good reason to do so (e.g., you're building up a collection of a poorly studied group and you need the DNA).
For everybody else, nature watching with a camera or sound recorder is all you need to get to know species and make big contributions to our understanding of NZ nature.