**3. Indigenous grasslands**

204 Biodiversity Loss in a Changing Planet

tropics. Kahikatea (*Dacrycarpus dacrydioides*) and Kauri (*Agathis australis*) are the tallest trees in New Zealand, and can reach up to 50 metres in height. At maturity these trees tower above the broadleaved canopy with other emergent podocarps like rimu (*Dacrydium cupressinum*), totara (*Podocarpus totara*), matai (*Prumnopitys taxifolia*), and miro (*Prumnopitys ferruginea*), to give the forest a layered appearance. Below the upper canopy many shorter trees, shrubs, vines, tree- and ground-ferns compete for space, and below them, mosses. Beech forests tend to be associated with southern latitudes and higher elevations, such as in mountainous areas, and are generally sparser than the podocarp-broadleaf forests. Their

Indigenous forests provide unique habitat for a large range of plants, animals, algae, and fungi. Since the arrival of Maori, circa 700 years ago and the subsequent burning of large areas of forest, and then Europeans from ~1840, who cleared large areas for farming and settlement, the extent of indigenous forest has significantly declined and, in combination with many introduced pests, has placed enormous pressure on the survival of many species. MfE (1997) reported that 56 of the listed threatened plant species are from indigenous forest habitats. Also, many of the seriously threatened endemic birds are forest dwellers: wrybill, kiwi, fernbird, kokako, kakariki, saddleback, weka, yellowhead, kaka, and New Zealand

The extent of indigenous forest in 2008 can be mapped using a combination of LCDB2 and LUM. Theoretically, the LUM contains a recent extent of indigenous forest. However, because the class definitions are land-use rather than land-cover based (for Kyoto Protocol), the indigenous forest class is not the same as the standard definition in LCDB2 and contains much indigenous shrubland yet to reach the maturity of a forest. Hence the LUM should only be used to report on changes to forest if the LCDB definition of indigenous forest is to be used. We therefore combined all the changes "from" or "to" forest in the LUM with

Figure 1 compares the extent of indigenous forest and shrubland in 2008 with the estimated pre-Maori historic extent, derived by combining LCDB2 and a historic map of New Zealand (McGlone, 1988). In the North Island, the area of indigenous forest has reduced from 11.2 million hectares to 2.6 million hectares. Most remaining indigenous forest is in the hills and mountains. In contrast to indigenous forest, indigenous shrublands have now become extensive, comprising over 1.0 million hectares. These shrublands often comprise a wide variety of indigenous shrub species and could naturally regenerate to indigenous forest if left. In the South Island, the area of indigenous forest has reduced from 12.0 million hectares to 3.9 million hectares, and, similar to the North Island, the remaining forest is mainly in the hills and mountains. At 0.6 million hectares, the area of indigenous shrublands in the South

The loss of indigenous forest between 1990 and 2008 may be assessed directly from the LUM. In the North Island, 29 thousand hectares of indigenous forest have been lost, and in the South Island, 22 thousand hectares of indigenous forest have been lost. The spatial location of this loss is important as some types of forest are better represented than others. We follow the method of Walker et al. (2006) who considered the area of indigenous forest remaining in land environments. The land environments are defined by unique combinations of climate, topographic, and soil attributes, and are a surrogate for unique assemblages of ecosystems and habitats (Leathwick et al., 2003). Four levels of classification have been defined with 20 level I, 100 level II, 200 level III and 500 level IV environments.

understory may contain only young beech saplings, ferns, and mosses.

LCDB2 to produce a recent extent of indigenous forest.

Island is as large as in the North Island.

falcon.

Approximately one half of New Zealand's land area is made up of a variety of exotic and indigenous grassland ecosystems. Approximately one-fifth of these grasslands comprise modified indigenous short and tall-tussock communities, which are mostly located on the South Island. Unlike many other indigenous ecosystems in New Zealand, they have a unique, partially human-induced origin. Once largely distributed in areas of lowland montane forest and shrubland, large regions of grassland were created through burning by Maori, especially for moa hunting and for encouraging bracken fern (*Pteridium aquilinum*), an important food source (Stevens et al., 1988; Ewers et al., 2006). Lowland podocarp forests hosting such species as totara (*Podocarpus totora*) and matai (*Prumnoptiys taxifolia*) were replaced by a variety of fire adapted grassland species, in particular the short tussock species *Festuca novae-zelandia* and *Poa cita*. Some 200 years later these species were progressively replaced by taller large grain *Chionochloa* spps (McGlone, 2001).

Provision of Natural Habitat for Biodiversity: Quantifying Recent Trends in New Zealand 207

(*Leptospermum scoparium*) and kanuka (*L. ericoides*) are more common and through time have

Though most New Zealand's indigenous grasslands have been modified to varying degrees by the indirect and direct effects of human activity, they continue to support a rich flora and fauna and are characterized by high species diversity (Dickinson et al., 1998; McGlone et al., 2001; Mark et al., 2009; Walker et al., 2008). However, recent changes in land-use activities have led to further fragmentation. An increasing area of indigenous grasslands (in the South Island), formerly used for extensive grazing, is being converted to intensive agriculture and areas once covered by indigenous grassland species are being progressively replaced with

Mark and McLennan (2005) assessed the loss of New Zealand's indigenous grasslands since European settlement, comparing the Pre-European extent of five major tussock grassland types with their current extent (using LCDB1). They estimated that in 1840, 31% of New Zealand was covered by tussock grasslands dominated by endemic tussock grass species. In 2002, however, just 44% of this area of indigenous grasslands remained, of which most was in the interior areas of the South Island. Of this, approximately 28% was protected with a bias towards the high-alpine areas. Remaining subalpine grassland communities (i.e. short tussock grasslands) still persisted, but were severely degraded and/or modified and under protected. Figure 3 illustrates the change in extent from pre-human to pre-European to

Fig. 3. Changes in the extent of New Zealand's indigenous grasslands since the arrival of

incremental and occurred at the paddock scale (less than 5 hectares).

Recent trends in land-use change suggest a movement towards increased production per hectare of land. Weeks et al. (in prep) estimated the current (2008) extent of indigenous grasslands and compared it with grassland in 1990. In 1990, 44% of New Zealand's indigenous grassland remained, by 2008 this was reduced to 43%. During this time there was an accelerated loss from 3,470 ha per year between 1990 and 2001 to 4,730 ha per year between 2001 and 2008. The majority of this change took place at lower altitudes (in short tussock grasslands) and on private or recently free-hold land. Most of the land-use change has been

established themselves among the grasses (Newsome, 1987).

exotic pasture, forestry plantations, and perennial crops.

current times.

humans.

Fig. 2. Percentage of indigenous forest lost between 1990 and 2008.

New Zealand's tussock grasslands have undergone a variety of transformations. In the South Island, much of the high country (tussock grasslands) was acquired from the Maori between 1844 and 1864 (Brower, 2008). During this time, pastoral licenses were granted for 1 year in Canterbury and 14 years in Otago, and the tussock landscape rapidly began to change. Lease holders used fire both to ready land for grazing and to facilitate travel. The result was a huge reduction in area of lowland and montane red tussock grasslands, the elimination of snow tussock from lowland eastern parts, and the reduction of snow-tussock found near settled areas. By the 20th century there was substantial loss of native species through conversion to vigorous exotic grasses maintained by the widespread use of fertilizers and herbicides.

Today, New Zealand's indigenous grasslands are dominated by grass species (Poaceae family) characterised by tussock growth (elsewhere known as "bunch grasses") (Ashdown & Lucas, 1987; Levy, 1951; Mark, 1965; Mark, 1993). The plant communities, however, vary from highly modified to areas with no exotic species (predominantly at elevations above 700 meters (Walker et al., 2006; Cieraad, 2008). Though tussock species *Chionochloa, Poa,* and *Festuca* are the dominant species in the landscape, numerous woody species are also present. At higher and more exposed sites with shallow soils and less available moisture, shrubs including the species of *Brachyglottis*, *Coprosma*, *Dracophyllum*, *Carydium*, *Hebe*, *Podocarps* and other *Olearia* spp dominate; at lower altitudes native shrub species such as manuka

Fig. 2. Percentage of indigenous forest lost between 1990 and 2008.

fertilizers and herbicides.

New Zealand's tussock grasslands have undergone a variety of transformations. In the South Island, much of the high country (tussock grasslands) was acquired from the Maori between 1844 and 1864 (Brower, 2008). During this time, pastoral licenses were granted for 1 year in Canterbury and 14 years in Otago, and the tussock landscape rapidly began to change. Lease holders used fire both to ready land for grazing and to facilitate travel. The result was a huge reduction in area of lowland and montane red tussock grasslands, the elimination of snow tussock from lowland eastern parts, and the reduction of snow-tussock found near settled areas. By the 20th century there was substantial loss of native species through conversion to vigorous exotic grasses maintained by the widespread use of

Today, New Zealand's indigenous grasslands are dominated by grass species (Poaceae family) characterised by tussock growth (elsewhere known as "bunch grasses") (Ashdown & Lucas, 1987; Levy, 1951; Mark, 1965; Mark, 1993). The plant communities, however, vary from highly modified to areas with no exotic species (predominantly at elevations above 700 meters (Walker et al., 2006; Cieraad, 2008). Though tussock species *Chionochloa, Poa,* and *Festuca* are the dominant species in the landscape, numerous woody species are also present. At higher and more exposed sites with shallow soils and less available moisture, shrubs including the species of *Brachyglottis*, *Coprosma*, *Dracophyllum*, *Carydium*, *Hebe*, *Podocarps* and other *Olearia* spp dominate; at lower altitudes native shrub species such as manuka (*Leptospermum scoparium*) and kanuka (*L. ericoides*) are more common and through time have established themselves among the grasses (Newsome, 1987).

Though most New Zealand's indigenous grasslands have been modified to varying degrees by the indirect and direct effects of human activity, they continue to support a rich flora and fauna and are characterized by high species diversity (Dickinson et al., 1998; McGlone et al., 2001; Mark et al., 2009; Walker et al., 2008). However, recent changes in land-use activities have led to further fragmentation. An increasing area of indigenous grasslands (in the South Island), formerly used for extensive grazing, is being converted to intensive agriculture and areas once covered by indigenous grassland species are being progressively replaced with exotic pasture, forestry plantations, and perennial crops.

Mark and McLennan (2005) assessed the loss of New Zealand's indigenous grasslands since European settlement, comparing the Pre-European extent of five major tussock grassland types with their current extent (using LCDB1). They estimated that in 1840, 31% of New Zealand was covered by tussock grasslands dominated by endemic tussock grass species. In 2002, however, just 44% of this area of indigenous grasslands remained, of which most was in the interior areas of the South Island. Of this, approximately 28% was protected with a bias towards the high-alpine areas. Remaining subalpine grassland communities (i.e. short tussock grasslands) still persisted, but were severely degraded and/or modified and under protected. Figure 3 illustrates the change in extent from pre-human to pre-European to current times.

Fig. 3. Changes in the extent of New Zealand's indigenous grasslands since the arrival of humans.

Recent trends in land-use change suggest a movement towards increased production per hectare of land. Weeks et al. (in prep) estimated the current (2008) extent of indigenous grasslands and compared it with grassland in 1990. In 1990, 44% of New Zealand's indigenous grassland remained, by 2008 this was reduced to 43%. During this time there was an accelerated loss from 3,470 ha per year between 1990 and 2001 to 4,730 ha per year between 2001 and 2008. The majority of this change took place at lower altitudes (in short tussock grasslands) and on private or recently free-hold land. Most of the land-use change has been incremental and occurred at the paddock scale (less than 5 hectares).

Provision of Natural Habitat for Biodiversity: Quantifying Recent Trends in New Zealand 209

Figure 4 compares the current extent of freshwater wetlands with its historic extent. The greatest losses occurred in the North Island where only 5% of historic wetlands remain compared with 16% in the South Island. The South and Stewart Islands contain 75% of all remaining wetland area, with the highest proportions persisting on the West Coast of the South Island and on Stewart Island. The remaining wetland sites are highly fragmented. Most sites (74%) are less than 10 ha in size, accounting for only 6% of national wetland area. Only 77 wetland sites are over 500 ha, accounting for over half of the national wetland area.

Fig. 4. Map comparison of current and historic extent of freshwater wetlands (blue areas) in

Classification of wetlands can be a challenge as they are dynamic environments, constantly responding to changes in water flow, nutrients, and substrate. Johnson & Gerbeaux (2004) clarified the definitions of wetland classes of New Zealand such as bog, pakihi, gumland, seepage, inland saline, marsh, swamps, and fens. By using GIS rules, it was possible to classify wetlands into their types and follow the trend of extent since historical times (Ausseil et al., 2011). Swamps and pakihi/gumland are the most common wetland types found in New Zealand. However, swamps have undergone the most extensive loss since European settlement, with only 6% of their original extent remaining (Figure 5). This is due to swamps sitting mainly in the lowland areas where conversion to productive land has been occurring. Unlike indigenous forest and indigenous grasslands, there is no national study describing recent loss over the last ten to twenty years for wetlands in New Zealand. However, some

New Zealand.

Continued impacts and reduced indigenous biodiversity are expected over the next century. In grazed areas, plant community composition should continue to alter gradually depending on stocking rates and variability in climate and disturbance regimes. As for areas that are completely converted to new land cover types, changes should be much more immediate. These conversions are likely to have significant impacts on the ecosystem structure and provision of ecosystem services.
