Recent loss of indigenous cover in New Zealand

Tags: environments, land environments, New Zealand, cover, Indigenous Forest, net loss, Ministry for the Environment, ha, Department of Conservation, Cambridge University Press, DOC, Wellington, land area, non-indigenous, grassland, Hamilton 3Department of Conservation, remaining, spatial databases, cover remaining, William G. Lee1 1Landcare Research, land cover, Private Bag, Robbie Price2, Dunedin, New Zealand, Conservation Policy Division of DOC, Kanuka, INDIGENOUS VEGETATION, Landcare Research Capability Funding, Landcare Research, pp, Steve Thompson, Kirsty Johnston, Rutledge, D.
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Recent loss of indigenous cover in New Zealand Susan Walker1*, Robbie Price2, Daniel Rutledge2, R.T. Theo Stephens3 and William G. Lee1 1Landcare Research, Private Bag 1930, Dunedin 2Landcare Research, Private Bag 3127, Hamilton 3Department of Conservation, Private Bag 1930, Dunedin, New Zealand *Author for correspondence (E-mail: [email protected]) Published on-line: 29 May 2006 ____________________________________________________________________________________________________________________________________ Abstract: Recently developed national spatial databases enable improved estimates of how much of the full range of New Zealand's terrestrial biodiversity pattern remains, its rates of change, and how much is legally protected. Analysis using a classification of land environments derived from soil and climate data layers (LENZ) as a surrogate for biodiversity pattern, and spatial databases of land cover and legal protection, shows extreme (>70%) loss of indigenous cover in 57% of land environments, and poor protection (<20% land area protected) in more than two thirds. Loss of indigenous cover has continued, with 49% of environments having lost indigenous cover from 1996/97 to 2001/02, and the highest rates occuring where indigenous cover was already most depleted. The Resource Management Act (1991) (an Act of Parliament bringing together laws governing land, air and water resources and concentrating on the environmental effects of human activities) and associated provisions have not halted these losses on private land. Monitoring progress towards halting biodiversity decline in New Zealand will depend on maintenance and updating of these national databases, and development of measures of processes that sustain indigenous species assemblages and ecosystem functions. ____________________________________________________________________________________________________________________________________ Keywords: loss of indigenous habitat; legal protection; rate of habitat loss; New Zealand
Introduction In order to meet international goals for the persistence of indigenous biodiversity, it is necessary to protect both biodiversity pattern (the full diversity of genes, species, communities, habitats and ecosystems, and landscapes) and the ecological and evolutionary processes that sustain this pattern (Margules & Pressey 2000; Moritz 2002). The goal of the New Zealand Biodiversity Strategy (DOC & MfE 2000) is consistent with this principle. The phrases "a full range" and "all species and subspecies" refer to biodiversity pattern, while the maintenance or restoration of a "healthy functioning state" implies the protection of essential biodiversity processes. The Strategy also identifies two key threats to indigenous species on land in New Zealand as `insufficient and fragmented habitat'(i.e. loss of biodiversity pattern) and `introduced invasive species which damage their habitat and important ecosystem processes', i.e. loss of biodiversity processes. Internationally, more progress has been made towards the objective measurement and description of biodiversity pattern than of biodiversity processes; this reflects the challenge of determining and measuring the key processes that sustain species assemblages and ecosystem functions across spatial scales. In New
Zealand, progress towards measures of both pattern and processes has been slow. However, national spatial databases of legal protection, land cover and abiotic drivers of terrestrial biodiversity have been recently developed; these allow us to better estimate how much of the full range of New Zealand's terrestrial biodiversity pattern remains, and how much is included within legally protected areas. Here we summarise the distribution of past and recent indigenous habitat loss, and legal protection for natural heritage, across land environments. Methods Our analyses combined three national spatial datasets, which we converted to 25 m GIS raster files. A combinatorial analysis of these datasets was run in GIS using the ArcSampling program developed by Landcare Research. This program created output tables for importing into a Microsoft Access database for final tabulation. We used Land Environments of New Zealand (LENZ) as a surrogate for the potential full range of terrestrial ecosystems and their associated biodiversity. LENZ is a classification of New Zealand's abiotic
New Zealand Journal of Ecology (2006) 30(2): 169-177 ©New Zealand Ecological Society
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terrestrial environmental pattern based on 15 environmental climate and landform variables likely to influence species distributions (Leathwick et al. 2003). We used the second Land Cover Database (LCDB2, based on 2001/02 imagery; Terralink 2004) to estimate remaining indigenous cover, and hence the change in indigenous cover from pre-settlement times to the present day, by land environment. For this, we assigned the 43 LCDB cover classes to either an indigenous (22 classes), or a non-indigenous (21 classes) category (Appendix 1). A few pixels identified as bare soil or inundated areas in LCDB2 had been classified within an exotic cover class in LCDB1. These pixels were assigned to the non-indigenous LCDB2 cover category (Walker et al. 2005). To identify recent changes in indigenous cover, we compared LCDB2 with the first LCDB (LCDB1; based on 1996/ 97 imagery, updated 2004 version with land classes consistent with LCDB2; Terralink 2004). To define legally protected lands we used a spatial database of private and public land managed for conservation (Protected Areas of New Zealand; PANZ) updated to May 2005. The database is an updated version of the legally protected areas database used for analyses by Walker et al. (2005), and includes all
public conservation lands and covenants administered for the purposes of natural heritage protection by DOC, QEII open space and Nga Whenua Rahui covenants, and Territorial local authority Regional Parks. Methods used to compile this database are described by Rutledge et al. (2004). To summarise results, we grouped the 500 Level IV land environments into six categories, following a combinatorial analysis of the three datasets. Five categories of `threatened environments' were defined on the basis of past habitat loss and current legal protection. Because loss of biodiversity accelerates as habitat loss advances (based on the shape of the generalised species-area relationship; Rosenweig 1995) the first three categories are environments where habitat loss has been greatest (i.e. those in which 0­10%, 10­ 20% and 20­30% indigenous cover remains nationally; Table 1; Fig 1A). Two further threat categories (critically underprotected and underprotected) include environments with more than 30% of their land area remaining in indigenous cover, but <10%, and 10­ 20% of their land area legally protected, respectively. These categories apply because indigenous habitats that are not legally protected are more likely to be cleared, and less likely to receive conservation
Figure 1. A. Environment threat categories based on % loss and % protection in May 2005 (Table 1) and B. rate of recent loss (% loss of indigenous cover in the five year period 1996/97 to 2001/02), across New Zealand's 500 Level IV land environments.
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Table 1. LENZ environments threat categories, and defining criteria (Walker et al. 2005). _______________________________________________________________
Category
Criterion
_______________________________________________________________
Acutely Threatened1
<10% indigenous cover remaining
Chronically Threatened1 10­20% indigenous cover remaining
At Risk1
20­30% indigenous cover remaining
Critically Underprotected >30% indigenous cover remaining <10% legally protected
Underprotected
>30% indigenous cover remaining 10­20% legally protected
No Threat Category
>30% indigenous cover remaining
>20% legally protected _______________________________________________________________
1In order of decreasing risk to remaining biodiversity cf the
national system for classifying species according to threat of
extinction (Molloy et al. 2002).
management inputs to mitigate threats (e.g. from pests and weeds). Together, the five categories of threatened environments are therefore likely to contain some of New Zealand's most severely reduced and poorly protected ecosystems, habitats and species. Environments with >20% of their area legally protected and >30% indigenous cover remaining were assigned to a sixth category. Results Indigenous cover remaining in 2001/02 LCDB2 data indicate that about one half of New Zealand's land area (12 632 214 ha, or 49%) remained under some form of indigenous cover in the summer of 2001/02 (Table 2). The loss of terrestrial indigenous cover since human settlement has been uneven across environments. The 284 environments retaining less than 30% indigenous cover comprise 57% of all 500 Level IV environments, and cover 42% of New
Table 2. Categories of New Zealand's land environments in 2001/02: a. number and % of environments, b. area and % of New Zealand, c. area of remaining indigenous cover and % of New Zealand, d. area remaining indigenous cover not legally protected, % of New Zealand, % of NZ indigenous cover, and % of indigenous cover that is not legally protected in threat category, and e. number of environments and % of environments in threat category with net loss of indigenous cover between 1996/97 and 2001/ 02. ____________________________________________________________________________________________________________________________________ Land Environment category
Total (all 500 Acutely
Chronically
At
Critically Under- Under-
No threat
environments) Threatened Threatened
Risk
protected
protected
category
____________________________________________________________________________________________________________________________________
a. Environments (LENZ Level IV)
No.
500
158
74
52
33
23
160
% Environments.
100.0
31.6
14.8
10.4
6.6
4.6
32.0
b. Full extent of environments
Area (ha)
26 000 680
% NZ
100.0
5 888 292 22.7
2 323 074 8.9
2 788 941 10.7
1 771 686 6.8
1 511 697 5.8
11 716 990 45.1
c. Indigenous cover (I) remaining in environments
Area (ha)
12 632 214
220 862
% NZ
48.6
0.8
% remaining in
"
3.8
indigenous cover
344 889 1.3 14.8
674 218 2.6 24.2
754 428 2.9 42.6
809 686 3.1 53.6
9 828 132 37.8 83.9
d. Indigenous cover not protected (INP) in environments
Area
4 795 569
184 916
% NZ
18.4
0.7
% NZ remaining I
38.0
1.5
% indigenous cover
38.0
83.7
not protected
289 103 1.1 2.3 83.8
468 250 1.8 3.7 69.5
673 178 2.6 5.3 89.2
571 598 2.2 4.5 70.6
2 608 525 10.0 20.6 26.5
e. Environments (LENZ Level IV) with net loss of indigenous cover between 1996/97 and 2001/02
No.
245
76
48
26
12
15
66
% of environments
49.0
48.1
64.9
50.0
36.4
65.2
42.5
in Threat Category ____________________________________________________________________________________________________________________________________
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Zealand's land area, mainly in the coastal, lowland and montane (or cool temperate; Wardle 1991 p. 78) zones (Fig 1A). In contrast, high proportions of indigenous cover remain in the subalpine and alpine zones. Almost one third (158, or 32%) of Level IV land environments retain less than 10% of their indigenous cover; these are categorised as acutely threatened environments and cover 23% of New Zealand's total land area. The average percentage of indigenous cover that remains in acutely threatened environments is 3.8% (Table 2). Current protection Just under one third (8 096 063 ha, or 31.1%) of New Zealand's land area had some legal protection recorded in the protected area database compiled in May 2005. However, protection exceeded 20% of the environment land area in just 162 (32.4%) of the 500 Level IV environments. Of the 12 632 214 ha of indigenous cover remaining in the summer of 2001/02, 4 795 569 ha (38%) was not identified as legally protected in the May 2005 protection database (Tables 2 and 3). Threatened environments In two thirds (67%) of land environments, indigenous cover had been reduced to less than 30% of its original extent (i.e. prior to human settlement) by summer 2001/02, and/or less than 20% of the land area was
legally protected (and hence likely to be receiving some level of management input to sustain biodiversity; Table 2) in May 2005. In the five threatened environment categories, high percentages (69.5­ 89.2%) of the area of remaining indigenous cover were not legally protected (Table 2). In environments with <30% indigenous cover remaining, unprotected indigenous cover was largely classified as Manuka and/or Kanuka, Indigenous Forest and Broadleaved Indigenous Hardwoods (Table 3). Extensive areas (690 774 ha) in these environments were classified as Low Producing Grassland, which we classify as non-indigenous, but which hold some indigenous ecosystems, habitats and species. In the Critically Underprotected and Underprotected environments, the most extensive indigenous cover classes were Tall Tussock Grassland (mainly in the inland eastern South Island high country), Manuka and/or Kanuka, and Indigenous Forest (largely in Eastern Regions of the North Island) (Table 3). Recent indigenous cover loss The area of non-indigenous cover in LCDB1 reclassified as indigenous cover in LCDB2 (the total gain) was only 346 ha (Table 4). The total area that changed from indigenous to non-indigenous land cover types between 1996/97 and 2001/02 (17 550 ha) was
Table 3. Indigenous cover not legally protected remaining in New Zealand 2001/02 (by LCDB2 class and class combinations). ____________________________________________________________________________________________________________________________________ Area in cover class and threat category (ha)
Cover class
Total (all 500 Acutely
Chronically
At
Critically
Under-
No threat
environments) Threatened Threatened
Risk
Underprotected protected
category
____________________________________________________________________________________________________________________________________
Indigenous cover not legally protected
Broadleaved Indigenous
348 763
Hardwoods
Depleted Grassland
226 184
Fernland
43 806
Grey Scrub
63 427
Indigenous Forest
1 360 167
Manuka and/or Kanuka
835 034
Matagouri
26 494
Tall-Tussock Grassland Alpine1 Rock2 Wetland/Water3
1 344 396 140 473 313 367 93 458
Total
4 795 569
31 424 3602 1016 3675 46 877 49 229 3628 5228 13 15 464 24 760 184 916
49 024 22 188 1738 8176 52 862 102 928 3177 23 122 106 12 906 12 876 289 103
52 320 26 633 1925 8528 166 978 132 803 6893 38 477 262 20 002 13 429 468 250
37 213 116 647 14 588 19 961 97 940 143 871 7820 204 206 5086 17 277 8569 673 178
32 553 10 901 4446 5196 104 754 85 021 818 295 919 12 214 13 509 6268 571 598
146 230 46 213 20 093 17 891 890 757 321 183 4157 777 444 122 793 234 209 27 556 2 608 525
Low producing grassland not legally protected
Low producing
1 511 719 146 104
238 944
305 726
403 595
99 706
317 643
grassland ____________________________________________________________________________________________________________________________________
1Alpine = Alpine Grass/ Herbfield, Permanent Snow and Ice, Subalpine Shrubland. 2Rock = Alpine Gravel and Rock, Coastal Sand and Gravel, Landslide, River and Lakeshore Gravel and Rock. 3Water/Wetland = Estuarine Open Water, Flaxland, Herbaceous Freshwater Vegetation, Herbaceous Saline Vegetation, Lake and Pond,
Mangrove, River.
WALKER ET AL.: RECENT LOSS OF INDIGENOUS VEGETATION
173
therefore very similar to the net loss of indigenous cover over that time (17 204 ha). The biggest changes from indigenous to nonindigenous cover types nationally were in Broadleaved Indigenous Hardwoods (6745 ha), Manuka and/or Kanuka (5609 ha), Tall-Tussock Grassland (2482 ha) and Indigenous Forest (2232 ha) (Table 4). Comparison of cover classes shows that planting of exotic forestry trees (represented by the Afforestation and Other Exotic forest cover classes) into areas of indigenous vegetation accounted for most of these changes (c. 11 557 ha or 65%). Harvesting or felling of 1982 ha of indigenous forest (Forest ­ Harvested LCDB2 class) accounted for 11% of the changes, conversion of indigenous vegetation to high-producing grassland (i.e. pasture) or cropland for 6%, and conversion of indigenous vegetation to low-producing grassland for 16% of the changes (Table 5). Of the low-producing grassland class in 1996/97, 29 338 ha changed to another non-indigenous class (Table 4), most of this through conversion to exotic forestry. The area of low-producing grassland affected by these changes is 1.67 times greater than the total national decrease in indigenous cover classes. Since many areas of low-producing grassland contain mixtures of indigenous and exotic species, significant
loss of indigenous biodiversity has likely occurred. There was a net loss of indigenous cover in almost half (245, or 49%) of Level IV land environments between 1996/97 and 2001/02 (Table 2; Fig 2A). Indigenous cover increased in just four (0.8%) environments, and these increases were relatively small (1 - 35 ha). Approximately 55% of the net loss of indigenous cover (9484 ha) was in threatened environments (Table 4). The largest net loss was in Chronically Threatened environments (2529 ha), but losses in At Risk (2207 ha) and Critically Underprotected (2406 ha) environments were almost as large. Most of the indigenous cover lost in the fiveyear period was on land not legally protected in May 2005 (94% of the total loss). In threatened environments, about 98% of indigenous cover lost was on land not defined as legally protected in May 2005. The area of indigenous cover recently lost was not related to the percentage of indigenous cover remaining in that environment in 1996/97 (Fig. 2A). However, rates of recent loss of indigenous cover (area lost, expressed as % of LCDB1 indigenous cover) were highest in environments where indigenous cover was already much reduced (Fig. 2B). Fig. 1B illustrates the geographic distribution of the rate of indigenous cover loss by land environment.
Table 4. Change and loss of indigenous cover (ha; 1996/97 to 2001/02) by environment threat category. ____________________________________________________________________________________________________________________________________ Area in cover class and threat category (ha)
Total
Acutely
Chronically
At
Critically
Under-
No threat
Threatened Threatened
Risk
Underprotected protected
category
____________________________________________________________________________________________________________________________________
Change from indigenous cover to non-indigenous cover
Broadleaved Indigenous
6745
552
Hardwoods
Fernland
90
0
Grey Scrub
46
7
Indigenous Forest
2232
145
Manuka and or Kanuka
5609
371
Matagouri
6
6
Tall Tussock Grassland
2482
47
Rock
234
1
Water/Wetland
105
17
Total
17 550
1147
635 0 2 249 1154 0 462 0 35 2537
1303 25 0 313 551 0 7 53 28 2281
598 2 1 534 798 0 478 2 0 2412
114 0 1 214 157 0 675 53 0 1214
3543 63 35 778 2577 0 813 125 24 7958
Change from non-indigenous cover to indigenous cover
All non-indigenous cover
346
20
classes
8
74
6
0
238
Net loss of indigenous cover Net loss of indigenous cover Net loss of indigenous cover not protected (% of net loss of indigenous cover)
17 204 16 153 (93.9)
1127 1114 (98.8)
2529 2495 (98.7)
2207 2187 (99.1)
2406
1214
2359 (98.0) 1094 (90.1)
7720 6904 (89.4)
Change from low-producing grassland to other non-indigenous cover
Low-producing grassland
29 338
3157
9135
6840
1287
3510
5409
____________________________________________________________________________________________________________________________________
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Table 5. Changes from indigenous to non-indigenous cover types (ha; 1996/97 to 2001/02). ____________________________________________________________________________________________________________________________________ Non-indigenous cover type 2001/02
Built-up
Surface Short-
High-
Low-
Gorse
Affore- Affore- Forest ­
Other
Total
Area
Mine Rotation Producing Producing
and/or
station station Harvested Exotic
Cropland
Exotic Grassland
Broom (not imaged) (imaged,
Forest
Grassland
post LCDB1)
____________________________________________________________________________________________________________________________________
Indigenous cover type 1996/97
Coastal Sand and
0
0
0
0
32
0
0
22
0
1
55
Gravel
River and Lakeshore
0
0
0
0
0
3
0
0
0
0
3
Gravel and Rock
Landslide
0
0
0
0
172
6
0
0
0
0
178
Tall-Tussock
0
0
0
0
0
0
54 1196
0
1236
2486
Grassland
Herbaceous Freshwater 0
2
0
55
0
0
38
6
0
0
101
Vegetation
Herbaceous Saline
0
0
0
86
0
0
0
0
0
0
86
Vegetation
Fernland
0
0
0
0
0
0
0
90
0
0
90
Manuka and/or Kanuka 0
8
0
565 2052
0
797 2148
3
42 5615
Matagouri
0
0
0
0
0
0
6
0
0
0
6
Broadleaved Indigenous 2
1
3
361
490
227
1802 3815
46
0 6748
Hardwoods
Subalpine Shrubland
0
0
0
0
0
0
0
46
0
0
46
Indigenous Forest
3
4
0
0
34
0
0
259 1934
0 2233
Total change % of 17 646 ha
5
16
3
1067 2779
236
2697 7582 1982
1278 17 646
0.0
0.1
0.0
6.0
15.7
1.3
15.3
43.0 11.2
7.2
Total in threatened
5
3
3
801 1765
222
1079 2947 1368
1238
9431
environments
% of 9 431 ha
<0.0
0.1 <0.0
5.6
15.8
1.3
15.4
43.2 11.3
7.3
____________________________________________________________________________________________________________________________________
Figure 2. Change from 1996/97 to 2001/02 in New Zealand's Level IV land environments (represented by green circles). A. Change in indigenous cover (% of whole environment). B. rate of change in indigenous cover (% of remaining indigenous cover in 1996/97). Red, orange and yellow shading dentoe Acutely Threatened, Chronically Threatened, and At Risk environments, respectively.
WALKER ET AL.: RECENT LOSS OF INDIGENOUS VEGETATION
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Discussion Historic and recent loss of indigenous cover Because of their accessibility and value for agriculture and settlement, New Zealand's coastal, lowland, and montane environments have been substantially modified, resulting in considerable loss of the indigenous biodiversity of these zones, and poor protection of what now remains. The much-reduced areas of indigenous cover remaining in these threatened environments support a disproportionately large percentage of New Zealand's most seriously threatened species (e.g. plants; de Lange et al. 2004), habitats and ecosystems. Although remaining indigenous ecosystems in these environments are typically highly modified, their protection is needed to halt the decline of New Zealand's indigenous biodiversity. Clearance of indigenous cover and associated loss of indigenous biodiversity continues throughout New Zealand, including in environments with the least remaining indigenous cover. Ongoing depletion of indigenous cover in threatened environments will exacerbate the loss of biodiversity, extinguishing local genotypes, species, and assemblages that have developed in response to distinctive environmental conditions. In New Zealand, clearance of indigenous cover was historically concentrated on land of highest value for agriculture. However, these data indicate that recent clearance extended to more marginal land, notably for exotic forestry. Despite biodiversity certification processes adopted by sectors of the forestry industry, LCDB data from 1996/97 to 2001/02 show that plantation forestry remained one of the major causes of indigenous cover loss in New Zealand. Overall, the data suggest that public awareness and education, voluntary protection, Resource Management Act (1991) provisions, and formal legal protection of remaining indigenous biodiversity have not halted the removal and/or displacement of vulnerable indigenous biodiversity in much reduced and poorly protected ecosystems and habitats. This may arise from a continuing perception that only pristine ecosystems are important or significant for biodiversity (e.g. Norton & Roper-Lindsay 2005). This fails to recognise that a high proportion of New Zealand's most threatened species survive only in depleted and highly modified ecosystems in threatened environments; therefore, protection of highly modified habitats is essential to prevent the extinction of many species. The need for more sophisticated assessment of biodiversity status and loss This analysis of indigenous land cover change was possible because of recent investment by Government
agencies in key national spatial databases. New Zealand's ability to assess and report on its performance regarding loss and protection of indigenous biodiversity will in future depend upon continued, multi-agency support for these key national databases. LCDB1 and LCDB2 data represent the first nationally comprehensive vegetation monitoring undertaken in New Zealand. However, they provide only a coarse assessment of changes in indigenous habitats and ecosystems, due to the broad qualitative nature of LCDB cover classes, the reliance on subjective manual distinction of spectral signatures, and resolution issues associated with the 1 ha minimum mapping unit used (Thompson et al. 2003). Incremental losses of habitat (e.g. forest edge dieback) and gradual trends (e.g. succession or habitat deterioration) are not detected, and mapping and classification errors in the databases remain unidentified but are likely to be large in relation to detected change. Grassland types and losses appear to be particularly poorly depicted. For example, LCDB1 vs LCDB2 comparison indicates that no conversion from tall tussock grassland to pasture occurred anywhere in New Zealand from 1996/ 97 to 2001/02. This is not credible, given the recent national trends in pasture development and intensification (Parliamentary Commissioner for the Environment 2004), and our LCDB comparison may therefore considerably underestimate the true loss of indigenous habitats and ecosystems. LENZ provides a first national classification of the abiotic component of ecosystems, based on explicit climate and soils data layers, but it does not distinguish very small-scale ecosystems which may support disproportionally high levels of indigenous biodiversity, including distinctive biogeographic and genetic components. Further, we do not yet understand how species richness and turnover varies across environments and biotic groups; therefore, by default, we treat LENZ environments as equal in biodiversity contribution. We know this is unrealistic. Finally, our legal protection data are binary, and provide no indication of the extent to which biodiversity is maintained. Intensive `mainland island' protection controls nearly all pests and weeds, but this is limited to very small areas (e.g. about 1.1% of the land administered by DOC). Direct clearance of indigenous cover is limited in other areas under legal protection, and some conservation inputs (e.g. stock fencing, pest and weed control) are applied, but we cannot assess the degree to which these inputs maintain biodiversity. The challenge of quantifying the state of New Zealand's biodiversity Effective policy and planning for biodiversity conservation in New Zealand depends on the
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development of national, multiscale, biodiversity assessment systems. These require spatially explicit abiotic and biotic national data layers, and innovative methods for integration and reporting. LENZ is a major step forward in depicting the abiotic components of terrestrial ecosystems, but its underlying climate and soil data layers must be maintained, updated and supplemented by the relevant agencies, leading to improved versions. Freshwater and marine environment classifications will be released shortly, and will require similar upkeep. Biotic inventory and monitoring in New Zealand is largely uncoordinated and underdeveloped. The land cover data layers (LCDB1, LCDB2) used in this study provide a rudimentary basis for regular assessments of changes in indigenous cover on land, while the legally protected areas database (PANZ) provides elementary information on its legal protection. As shown here, when integrated with LENZ environments, these surrogate databases can provide national indices of representativeness (i.e. the continuing existence of natural habitats and their legal protection across land environments). These indices can be tracked over time to indicate progress towards conservation goals provided that date-stamped updates are funded by the relevant national agencies. In summary, this analysis represents some progress towards the objective measurement and description of biodiversity pattern in New Zealand, and can provide improved guidance on priorities for protection (e.g. through district plans' constraints on clearance, or other legal protection mechanisms). However, the component national datasets still have limited thematic resolution, and there is currently no provision for maintaining and updating the national environment and land cover datasets. A far greater challenge lies in developing measurements of, and systems for, reporting changes in the key processes (e.g adaptation, reproduction, dispersal) that sustain indigenous species, their assemblages, and ecosystem functions. This is particularly important in New Zealand due to the high vulnerability of the biota to invasive species (Atkinson & Cameron 1993). Coordinated national assessment of pressures on biodiversity and their impacts on biodiversity processes are needed to supplement measures of pattern before it is possible to assess how much of the full range of indigenous biodiversity persists, how rapidly it is being lost, and how adequately resources allocated to different biodiversity conservation activities protect it. We recognise the importance of these issues, and the need for other, complementary, biodiversity assessment tools to enable more effective and systematic biodiversity conservation in New Zealand.
Acknowledgements This paper was funded by Landcare Research Capability Funding (SW and DR) from the Foundation for Research, Science and Technology, and by the Conservation Policy Division of DOC (RP). Data were developed with support from many government agencies, in particular the Ministry for the Environment. DOC, the QEII National Trust, Nga Whenua Rahui and Wellington and Auckland Regional Councils all made substantial contributions towards the national database of protected land, and we particularly thank Deb Zanders, Anne Brookes, Phil Barlow, Shona Myers, John Gibson, Philippa Crisp, and Kirsty Johnston for facilitating data transfer. We thank Steve Thompson for LCDB support and advice, LINZ for funding the most recent update of PANZ (May 2005), and Craig Briggs for his assistance in coordinating and compiling the database. Many colleagues made formative contributions to the ideas presented here: in particular Matt McGlone, Jake Overton, John Dymond and Geoff Rogers. For facilitating the contracts that enabled the development of these ideas, we thank Grant Hunter, Robin MacIntosh, Doris Johnston, Allen Shepherd, and Kirsty Johnston. References Atkinson I.A.E.; Cameron, E.K. 1993. Human influence on the terrestrial biota and biotic communities of New Zealand. Trends in Evolution and Ecology 8: 447­451. de Lange, P.J.; Norton, D.A.; Heenan, P.B.; Courtney, S.P.; Molloy, B.P.J.; Ogle, C.C.; Rance, B.D.; Johnson, P.N. 2004: Threatened and uncommon plants of New Zealand. New Zealand Journal of Botany 42: 45­76. DOC & MfE 2000. The New Zealand biodiversity strategy. Department of Conservation (DOC); Ministry for the Environment (MfE), Wellington, N.Z. 163 pp. Leathwick, J.R.; Wilson, G.; Rutledge, D.; Wardle, P.; Morgan, F.; Johnston, K.; McLeod, M.; Kirkpatrick, R. 2003a: Land environments of New Zealand. David Bateman, Auckland, New Zealand. 184 pp. Margules, C.R.; Pressey, R.L. 2000. Systematic conservation planning. Nature 405: 243-253. Molloy, J.; Bell, B.; Clout, M.; de Lange, P.; Gibbs, G.; Given, D.; Norton, D.; Smith. N.; Stephens, T. 2002: Classifying species according to threat of extinction: A system for New Zealand. Threatened Species Occasional Publication 22. Department of Conservation, Wellington, New Zealand. 26 pp.
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