What are drylands?

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What are drylands?
Background information for a meeting to discuss
drylands in the revised Otago CMS Grant Norbury
and Susan Walker Landcare Research, Dunedin and
Alexandra April 2010
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Drylands Contain some of the most transformed,
least protected and most threatened native
ecosystems and species in New Zealand Are
unstable, seral, rapidly changing, invaded
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In seeking to protect and restore drylands, we
face Limited knowledge, experience and science
to support biodiversity managers Poor agency and
community awareness of dryland biodiversity and
its protection needs
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A first attempt to define a New Zealand Dryland
Zone
Rogers et all (2005) Science for Conservation.
http//www.doc.govt.nz/upload/documents/science-an
d-technical/SFC258.pdf
Area 50,500 km2
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B. North Island Hill Country Relatively moist
(high rainfall potential evapotranspiration
ratio) environment with infertile soils, often
derived from younger sedimentary rocks such as
mudstones and siltstones.
A. Gisborne-Hawkes Bay This is the most
northerly group of dryland environments. On
average, they experience the most variable
rainfall, the least severe and latest frosts, the
highest winter and summer solar radiation, and
the highest mean annual temperatures.
Dryland Types (including Manawatu)
D. Coastal Marborough Kaikoura Coast inland
North Canterbury The driest and sunniest
dryland environment type, experiencing the
highest atmospheric and soil moisture deficits
and the highest average summer solar radiation.
Soil fertility is generally high, and there are
few chemical limitations to plant growth.
D. Coastal Marborough Kaikoura Coast inland
North Canterbury The driest and sunniest dryland
environment type, experiencing the highest
atmospheric and soil moisture deficits and the
highest average summer solar radiation. Soil
fertility is generally high, and there are few
chemical limitations to plant growth.
Types are defined based on environmental
factors only (not plants and animals)
C. Wairarapa Wellington Coast Nelson.
Typically comprising young, fine sediments, often
poorly-drained substrates with saline chemical
limitations to forest growth, low atmospheric and
soil moisture deficits.
C. Wairarapa Wellington Coast Nelson -
Manawatu Typically comprising young, fine
sediments, often poorly drained substrates with
saline chemical limitations to forest growth, low
atmospheric and soil moisture deficits.
E Marlborough North Canterbury The
highest-elevation group of dryland environments,
including relatively steeply sloping,
well-drained foothills of the Marlborough and
North Canterbury mountain ranges, characterised
by high atmospheric moisture deficits. Older
substrates predominate, and calcareous younger
sedimentary rocks and older sedimentary rocks
(e.g argillite) feature strongly.
The Units we grouped into Types are (LENZ Lvl
IV) land environments
F Canterbury Plains and Otago inland basin
alluvium and loess These environments combine
low temperatures and low solar radiation inputs,
which reflect southern latitude, with
characteristic alluvial and loessial substrates.
H Mackenzie Basin and Central Otago This group
of environments covers the steeply sloping
foothills of these basins, and is characterised
by low atmospheric water deficts, low mean annual
temperatures, low solar radiation inputs, and
severe, early winter frosts, all reflecting
southern latitude. Soils are often alluvial, and
predominantly derived from schist.
G Inland southern south island basins and
valley floors Complex of Nine groups, highly
variable, cool, with v. variable moisture regimes
and substrates. Most totara, fairly high notsol,
6.Mat 7.Hall (share high with H), High Comp1
(share high with H), southerly, low mat, low
junes, lwo decsol, highest jdgfrost, among
earliersty fafrost, lowest rnvar, r2pet, among
highest pendef (but low octvpd), high acidp, high
sc (but not as high as h), among highest al,
highest elev.
G Inland southern South Island basins and
valley floors This group of environments is
highly variable, and distinguished by high
elevation, severe frosts, low mean annual
temperatures, low solar radiation inputs and
relatively consistent annual rainfall. Soil
moisture deficits are high, but atmospheric water
deficts tend to be low. Soils are generally
schist and alluvium derived and relatively
fertile (with high acid-soluble phosphate).
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TOTAL NZ LAND AREA
Area 50,500 km2
Dryland ecosystems have been extensively cleared
19.4 DRYLAND
REMAINING PREDOMINANTLY INDIGENOUS ECOSYSTEMS
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TOTAL NZ LAND AREA
Area 50,500 km2
And have extremely poor protection
19.4 DRYLAND
AREA LEGALLY PROTECTED (COVENANTS, DOC etc)
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TOTAL NZ LAND AREA
Area 50,500 km2
But support high proportions of NZs most
threatened plants, invertebrates and lizards
19.4 DRYLAND
PROPORTION OF NZs MOST THREATENED PLANTS
NB lists s not updated to Townsend et al 2008/
de Lange et al 2009!
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TOTAL NZ LAND AREA
Area 50,500 km2
More threatened than average
19.4 DRYLAND
THREAT CATEGORIES (PLANTS)
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Drylands in Otago Conservancy
DOC Area Dryland Central
Otago 69.7 Wanaka 30.3 Coastal
Otago 26.2 Wakatipu 16.0
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Drylands in Otago Conservancy

• H Southern dry hill country
• Mainly steep foothills of the basins
• inland, so high elevation
• cool, severe frosts, low solar radiation
• But smaller soil moisture deficits than G
• Schist-derived soils

• G Inland southern South Island basins and
  valley floors
• Highly variable, but distinguished by
• inland, so high elevation
• cool, severe frosts, low solar radiation
• Big soil water deficits, BUT low air water
  deficits
• Fertile schist and alluvium-derived soils

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REMAINING PREDOMINANTLY INDIGENOUS ECOSYSTEMS
AREA LEGALLY PROTECTED (COVENANTS, DOC etc)
G Inland southern South Island basins and
valley floors
H Southern dry hill country
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G Inland southern South Island basins and
valley floors
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G Inland southern South Island basins and
valley floors
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H Southern dry hill country
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H Southern dry hill country
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All of NZ
Acutely Threatened Chronically Threatened At
Risk Critically Underprotected Underprotected No
threat category
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Threatened environments

• Combination of 3 national datasets
• Divides country into 6 threat categories
• based mainly on
• past loss of indigenous vegetation ( indigenous
  cover left)
• but also on
• current legal protection ( protected)

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Threatened environments
Category Category Criteria Category Name
1 lt10 indigenous cover left Acutely Threatened
2 1020 left Chronically Threatened
3 2030 left At Risk
4 gt30 left and lt10 protected Critically Underprotected
5 gt30 left and 1020 protected Underprotected
6 gt30 left and gt20 protected Less Reduced and Better Protected
No Data
based on indigenous cover left, no matter how
much protected
based on indigenous cover left (gt30) left AND
how much protected
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Otago
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Otago Conservancys Threatened Environments
New Zealand
Otago Conservancy as a whole
Environment Threat Categories (Proportion Land
Area)
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This Regions Threatened Environments
New Zealand
Otago DRYLANDS
Environment Threat Categories (Proportion Land
Area)
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Threat_category_name Wanaka Wakatipu Central Otago Coastal Otago
Acutely Threatened 24.4 14.7 30.1 58.9
Chronically Threatened 14.5 13.9 27.3 27.8
At Risk 3.0 3.0 10.1 11.4
Critically Underprotected 57.9 68.0 32.4 1.9
Underprotected 0.1 0.3 0.1 0.0
Less reduced and better protected 0.1 0.1 0.0 0.0