What is biodiversity and why is it important?
Nancy Willems, Environmental consultant at Place Group environmental planning.
Biodiversity is the variety of life on the planet. It includes genes, species, ecosystems, native and non-native plants and animals, and the relationships between them. New Zealand is known internationally for its unusual native plants and animals, many of which are found nowhere else in the world. This makes it especially important that we’re doing what we can to protect our native species and ecosystems.
As well as the value of biodiversity for its own sake, it provides a range of services to the wider environment such as capturing and filtering water, as well as protecting steep and unstable areas from erosion. Wetlands capture surface run-off and leaching, and filter some of the nutrients out of the water before it is discharged into waterways and estuaries. Other benefits of protecting these wetlands, include improving stock management and preventing cows getting stuck in wetlands.
While about a third of New Zealand is held as public conservation land, these protected areas don’t contain the full range of ecosystems, species and habitats. This makes it essential that biodiversity on private land is protected and managed to maintain the full suite of New Zealand’s native biodiversity. Protection doesn’t have to mean legal protection, although this does secure a biodiversity site for the future. Physical protection and active management are important ways to make meaningful gains. It’s not just mature forest or large wetlands that provide value – areas of regenerating scrub play a key role in landscape scale processes, so that as mature forest collapses in one area, new areas are developing to replace it. Small wetlands and valley bottom seeps can provide significant filtering capability for their size and can support threatened plants.
There also doesn’t need to be a trade-off between biodiversity and production. The two can work together, and undertaking a farm/orchard planning approach that integrates biodiversity with water, soil and profitability can deliver multiple benefits. If your property holds something really special, a threatened species for example, or a particular forest or ecosystem type that is uncommon, either naturally or because it has been reduced over time, protecting that site or species is a contribution to its national survival.
Some areas of forest can look fine from the outside – or to the untrained eye – but are actually in poor condition. They can be in the process of being overtaken by exotic weeds and pest animals or the inside of the forest structure can be missing the lower layers and ground cover due to grazing farm stock, deer, goats or pigs. In some areas these lower layers have been overtaken by weeds like privet that are able to establish and thrive under a full canopy, with only the upper layers mostly native.
What can you do?
There are some really simple things that can be done on farm to protect biodiversity and gain some benefits from doing so:
- Fencing stock out of wetlands and areas of bush is always the first step. This can also help to configure farm, orchard blocks and tracks in practical ways to improve other operational aspects of running the farm. Stock exclusion means that native plants can regenerate and provide habitat for the species that inhabit those areas. Wetlands are particularly rich in birdlife. Many of the birds that are found in wetlands, like the spotless crake, are not found in any other habitats. The fence defines the boundaries of the areas you want to protect, reducing the potential for clearance and damage around the edges. A buffer zone around high value areas should be allowed for inside the fence.
- Pest management is key. Many biodiversity areas are under constant attack from pest plants and animals, and smaller areas are more vulnerable to these attacks. Fencing a bush block will allow the forest to regenerate, with ground cover and understorey species able to re-grow, however, weeds can also re-grow and compete with natives. Some weed species are especially damaging to native bush because they grow quickly, produce a lot of seed or smother native vegetation, and prevent regeneration. Early control of weeds is vital, making control cheaper and more effective, rather than waiting until it is a big problem that is difficult and expensive to mend. High numbers of deer and goats will prevent the ground cover and understorey from recovering. Control of these animals is essential if the forest is to regenerate. Possums and – in some places – wallabies, will need to be controlled for the forest to regain its health.
Seeking advice for cost effective approaches is essential and persistence is needed to get it right, ensuring time and funds are not wasted. If you have a problem that you’re not sure how to tackle, get some advice from someone who has the expertise and experience to help you plan your work. There are many resources available to help get your thinking underway, and some expert guidance will help you achieve some great outcomes.
You don’t need to tackle everything at once. Take it one step at a time, plan your project, think about how much you can manage at any one time and do that well. You will get a better outcome from taking the time to do each small section thoroughly.
Resources to get you started:
Bay of Plenty Wetland Restoration Guide
Wetland Restoration: A Handbook for New Zealand Freshwater Systems
Native Forest Restoration - a practical guide for landowners
Bay of Plenty Regional Guide - Trees That Count
Getting riparian planting right in the Bay of Plenty
Bay of Plenty Regional Council - land management advice