Biodiversity Issues

As climate change brings changing environmental conditions, we can expect plants (and animals) that have not previously been part of the local ecosystem to raise biodiversity issues. What can be done in the face of the creeping spread of new plant species?

Biodiversity refers to the range of organisms ordinarily present in a particular ecosystem. Indigenous biodiversity refers to all plants and animals that occur naturally in Aotearoa New Zealand and have evolved or arrived without any assistance from humans. Protecting this diversity of organisms is important for the health of the entire ecosystem: the smaller the diversity, the less likely that the full range of environmental niches will exist to maintain all organisms in a flourishing whole. Eco-systems are made up of interdependent relationships where the impact of one organism’s decline or abundance can affect the ability of other members of the ecosystem to survive and thrive.

Ōtautahi Christchurch has several biodiversity strategies designed to maintain biodiversity across the city and province, not that ecosystems take any notice of Local Government boundaries. At a regional level sits the Canterbury Regional Biodiversity Strategy, a non-statutory document that establishes a framework of goals and priorities for undertaking biodiversity initiatives but which indicates the challenge facing us in its first three sentences: “In Canterbury, the native plants and animals and the landscapes and ecosystems that support them, are recognised nationally and in some cases internationally, as defining this place. They also form a fundamental part of the cultural identity and heritage of Ngāi Tahu, of subsequent settlers, and of the Canterbury community today. However, since the arrival of humans, there has been a significant decline in our indigenous biodiversity.”

Ōtautahi Christchurch City Council has its own Biodiversity Strategy written pre-earthquake; it is in need of a refresh. Nonetheless, the strategy does what it says on the cover indicating that its goals include:

• to conserve and restore indigenous biodiversity in Christchurch and Banks Peninsula
• priority species are protected and restored
• ecosystems supporting biodiversity are protected and restored
• species and habitats important to Ngāi Tahu are protected and restored
• pests are managed to minimise their impact on biodiversity
• new Council policies will take account of the Biodiversity Strategy.

The goal “pests are managed to minimise their impact on biodiversity” has gained importance as climate change has become more noticeable and the Predator Free 2050 programme has gained ground. Unfortunately, in the world of plants, Aotearoa New Zealand has the dubious honour of being one of the most “weedy” countries in the world; in fact, weedy plants now outnumber indigenous ones. In 2014, a running total (www.nzflora.info) indicated that there are more than 2370 fully naturalised taxa compared with about 2230 indigenous representatives. Te Ara Encyclopaedia of New Zealand states that “about 75% of land weeds and over 50% of freshwater weeds were originally grown in gardens or home aquariums. On average, eight species of garden plant each year become naturalised in the wild.”

Given all of this, you would not be surprised to know that the CCC has its own “Operational Pest Plant Management Plan” which the CCC Regional Parks team use in their programme of active work to combat pest plants in Christchurch’s regional parks. But what, you might ask, is happening in and along our urban waterways, beside our roads and transport routes or within the city’s numerous urban park spaces?

While the CCC Operational Pest Plant Management Plan endeavours to knit together and harness the work of Three Waters, Transport and Parks Units in a coordinated endeavour to manage pest plants, the plan itself has no impact as yet within Three Waters, Transport and Community Parks. Inexplicably, these Units have yet to be managed into a position where they can agree to be involved and where funding is harnessed to achieve co-ordinated pest plant management.

The plan itself presages this problem: “The ability of the Council to adequately meet its pest control obligations is limited by responsibilities being shared across a fragmented structure among several Council units that are poorly integrated. As a result, there is a lack of consistency in resourcing, effort, and a serious lack of understanding of weed presence and distribution across the Council’s full jurisdiction. To address this, consideration could be given to establishing a more centralised structure within the Council by establishing a “one stop shop” that has responsibility for all the Council’s pest control obligations. In any case, all Council units responsible for pest control should dedicate adequate resources to meet its pest control obligations, and the control undertaken by each unit should be a key performance measure in annual reporting. CCC Operational Pest Plant Management Plan 2022 – 2032, p4”

When an operational plan puts it so clearly and succinctly, there really is not much excuse left for council managers not to get into some active managing of a very real issue that affects every part of our environment, and to fund it appropriately. OHRN will be following this up in our Long Term Plan submissions.