Restoration of Urban Biodiversity a big picture look at some key issues Colin D Meurk [email protected] 18 th & 20 th May, 2004.

Restoration of Urban Biodiversity

a big picture look at some key issues

Colin D Meurk

[email protected]

18th & 20th May, 2004

What is Biodiversity?

• Summation of global ecosystem, species, and gene information (sum of all the regional diversity)

• Distinct from local species richness - total number of species in an area

• Misconception that piling more (exotic) spp into an area increases biodiversity

• NZ has huge numbers of introduced spp; net increase of 58 vertebrates, but net decline of indigenous spp (-53). Global biodiversity is thus reduced by 53 - not increased by 58!

• NZ has c. 30 000 exotic plant spp, so spp richness is now c. 32 500, but global biodiversity has declined through massive reduction in gene pools & functional ecosystems – not increased by 30 000!

Extinction is forever!% of endemic group that is:

extinct, threatened or endangered

• 100% NZ frogs• 100% tuatara• 100% moa and overall …• 100% kiwi• 100% aptornis 29% NZ breeding seabirds• 100% kakapo• 66% kea & kaka 56% NZ breeding non-marine birds• 66% NZ wrens• 33% whiteheads Protection of all of these is our duty!• 100% piopio• 100% wattlebirds• 100% short-tailed bats Ref: Kerry-Jane Wilson 2004

Why Urban?

• Most people live in urban environments (creates both risks & resources)

• Cities are at environmental cross-roads• Thus have diverse ecosystems & spp• These lowland biota are at risk & under-protected• Few citizens see our nature - in remote mountains,

rainforests & offshore islands• Some positive indicators in cities/towns• Conservation of nature depends on both ecological &

socio-cultural factors– it won’t happen if there is not the will

• There must be a critical ecological, visual & ideological mass of nature so that it is sustainable thru being equated with society’s sense of its place.

Sustainable Management & UseSustainable Management & Useof natural resources

IdentificationIdentificationwith regional biodiversity & landscape

ProtectivenessProtectivenesstowards natural values

VisibilityVisibilityof nature

LearningLearningfrom natural processes

EnculturationEnculturationof natural values

Quality of LifeQuality of Lifedefinition

FamiliarityFamiliaritywith nature

Landscape & Ecological

Sustainability & Integrity Feedback

System

We have the need for a major Urban Biodiversity Restoration

effort

• Biodiversity crisis

• Cultural imperatives (both Maori & Kiwi)

• Critical location

• Do we have the ecological technology?

What can we do?

• Protect the primary habitats– More urban biodiversity & habitats than we think– More expensive to restore than we think

• Nurse the remnants back to health – at various levels & scales– A single bush is a habitat!– Mainland islands the Rolls Royce version

• Halt deliberate & natural spread of weeds & pests!• Restoration & Regeneration

– Remember the diversity is in the small spp (<20% of native flora are large trees, shrubs & tussocks) and the myriad interactions

• Raise proportion of native plants in dominant locations• Nurture the home gardener - Gardens, footpath cracks,

walls & lawns• Integrate sanctuaries, corridors, stepping stones & the

matrix – and people!

How/Where do we do it?• Get the management of remnants & the investment in

planting right!• Forest planting (defines the city & food value)• Shrubland systems (a special NZ feature)• Wetland restoration (tall stuff is easy)• Coastal dune & estuarine restoration• Grasslands (battling weed successions)• Riparian & instream habitats (battling perceptions)• New surrogate habitats (urban mimics of nature)• Facilitate spatial dynamics (the landscape level)• Celebrate & redirect the home gardener’s energy &

innovation (cf bird breeders)

Forests & Shrublandsinnovative ways of making urban forests pay

• G Hall LINKNZ 15.4.03; Douglas fir - harvest 20% at yr 20, natives introduced at yr 20, then 20% stems > 30 cm harvested, leaving 12 stems/ha

Reports of bellbirds by the public in Christchurch between 2001-2004

Wetlands & Riparian Habitats

Key Message: Plant at stream edges, tall & dense (during low water/summer time) – but provide windows for access & views

Coastal Estuaries

Good dune, bad dune

Grasslands are tricky in a forest climate!

Combat exotic grasses with differential grazing …

Handweeding & close inspection – or moaing

Give in to the wood climate

Stressing with coarse soil or managed drought

Urban Surrogates of Threatened Nature

Lawns are surrogate interdune turfs

Creative Native Gardens

Towards landscape integrity & legibilitysocial cohesion & a maturing culture

Power of plants & their signals

Entrances, Portals & Avenues are crucial

It took over a millennium in Europe to fit in with the land

- be patient!

We need to grow From this

To this

Comfortable, mature & secure in our history, work, art & play

Take home messages

• Biodiversity a global concept – a crisis in NZ• Urban is the focus – identity, cultural imperative• Need critical mass of nature – visually, culturally, &

ideologically• Protect primary habitats – the benchmarks• Halt deliberate & natural spread of pests• Restore & regenerate (80% plants-small stuff)• Urban woodland defines the city & food value• Need visual dominance of native spp.• Optimum spatial configuration of forest patches• It’s for the birds

For messages

• Safety – need some ecologists to help with the solutions

• Plant stream edges dense + windows• Estuaries – buffers, excavation & regen.• Dunes losing their natural character• Grasses fun but tricky in forest climates -• …grazing, weeding, stressing, go to shrubs• Role of home gardener – creative natives• Urban surrogates of threatened habitats/spp• Maturing the culture & the landscape -

legibility

References

• Coastal Dune Vegetation Network (CDVN website www.forestresearch.com/research/cooperatives )

• www.bush.org.nz/planterguide (includes plant selection & propagation tools, soil key, streamside planting guides)

• Establishing shelter in Canterbury with Nature Conservation in mind (ECan & Isaac Centre for Nature Conservation)

• Protecting & Restoring our natural heritage – a practical guide (Davis & Meurk for DoC 2001)

• QEII handbook (in press)• The Native Garden (Gabites & Lucas 1998)• Tane’s Tree Trust