SoE 2006 > Biodiversity > 6.3 Terrestrial species diversity

6.3 Terrestrial species diversity

Four species presumed extinct have been rediscovered, but listings of threatened species have increased by 5% and threatened populations and communities by 22% in the current reporting cycle.

The diversity of terrestrial species in NSW remains under threat and response mechanisms to protect them have not yet reversed this trend.

No additional species have been listed as extinct in NSW and four previously considered extinct have been rediscovered. However, the number of species listed as threatened has increased by 47, and there are an additional 25 threatened populations and communities.

The distribution and abundance of many species not listed as threatened continues to decline due to habitat destruction and other pressures.

Far-reaching legislative changes to protect biodiversity and habitat have been introduced and many of these address the threats and processes that drive the decline in biodiversity.

NSW indicators

Introduction

The National Land and Water Resources Audit (NLWRA 2002a) stated:

'There has been a massive contraction in the geographical ranges and species composition of Australia's indigenous mammal fauna over the last 100+ years. One-third of the world's extinct mammals since 1600 AD are Australian. Such a record is unparalleled in any other component of Australia's biodiversity, or anywhere else in the world.'

Many factors are contributing to the decline of biodiversity including loss of habitat, reduction in soil condition and water quality, invasive species and modification of ecosystems. Accompanying the continuing loss of native species is a significant reduction in the capacity of natural systems to support human requirements (NRMMC 2005).

The true level of decline is unknown as the number of species is much greater than the state of knowledge about them (Possingham et al. 2002). The conservation status of vertebrate fauna and vascular plants is, in the most part, well known. However, the vast majority of species that make up our biodiversity, such as invertebrates, have not been described, with their ecological functions known only in general terms and their conservation status not known at all in most cases. This lack of knowledge of the full potential of impacts may itself contribute to biodiversity loss.

Some populations in the wild may already be at levels that are not viable. Even where pressures on species are reduced, lag effects may be felt for many years (Possingham et al. 2002). Different threats have different timelags and for some – such as the impacts of expanding weed and pest populations, habitat fragmentation or climate change – it may take many years for the full effects to become evident.

Current status and trends

Extinct and threatened species, populations and communities

More than a quarter of the terrestrial vertebrate animals in NSW are listed as threatened under the Threatened Species Conservation Act 1995 (TSC Act) (Table 6.7). The proportion of terrestrial vascular plants listed is about 12%. The number of animal species reliant on those plant species is unquantified but is thought to be significant.

Table 6.7: Terrestrial species, populations and ecological communities listed under the TSC Act

Source: DEC data April 2006

Note: ^(a) This entry does not include algae. There is insufficient information to provide an estimate of the total number of species of algae in NSW.

Between December 2002 and April 2006, the listing of endangered and vulnerable species, and endangered ecological communities and populations has grown considerably with 45 species added to the endangered list and six to the vulnerable list (Table 6.7). Four species – three plants and one mammal – previously thought to be extinct, were rediscovered and their listings changed to endangered. The number of endangered ecological communities has increased by more than 22%. Endangered ecological communities listed under the TSC Act may also include aquatic ecosystems (see Biodiversity 6.6).

These increases reflect the ongoing impact of land-management practices, as well as the improved understanding of the conservation status of many species and communities and the processes for recognising and listing them. For both these reasons, this trend of increasing listings is expected to continue.

Extinction of a species affects the wider environment, including other associated and dependent species, such as invertebrates and fungi. Possingham et al. 2002 have estimated that up to 600 other species might be at risk from a threat that causes the extinction of just one bird species. Much of this loss is not apparent because it is slow and hard to detect.

Species information

Many species are not listed as 'vulnerable' or 'endangered' even though their abundance and range may be declining. Therefore, TSC Act listings do not give a complete picture of the broader decline occurring across the State as habitats shrink and become fragmented, reducing ecological ranges and genetic diversity. Another problem may be the considerable timelag involved in the process of identifying a species of concern, nominating it for listing and obtaining the data to finally determine its status. Decline in the size and range of individual populations might be a useful proxy for biodiversity decline, but is generally not monitored systematically.

The diversity of bird populations, however, has proved to be a useful indicator of biodiversity because of their sensitivity to environmental changes and the quality of taxonomic and ecological data available. One-quarter of bird species in NSW have suffered significant declines in the last 20 years, ranging between 21% and 58% of species across NSW bioregions (Reid 2000; Birds Australia 2002). The decline of bird species in NSW has been greater than that for Australia as a whole, which showed a 15% decline in the species surveyed (Birds Australia 2002).

The populations of several common and widespread woodland birds of the extensively cleared wheat–sheep belt continue to decline and several migratory shorebird species also show evidence of a long-term reduction in numbers (Olsen et al. 2005).

Conservation efforts have been directed at rare species but relatively little action has been taken to improve the fortunes of more common declining species. Climate change is also placing alpine bird species under pressure (Olsen et al. 2003).

Of the 89 species of forest mammals in NSW, eight are presumed extinct within the State and 40 are currently threatened. However, 34 of the 41 non-threatened species are also in decline. It is expected that most forest mammals of NSW will continue to decline as the human population expands and demand for prime land increases (Lunney & Matthews 2004). These processes will be exacerbated by the effects of drought, climate change, fire, pests and weeds on natural forest structure and function. For instance, the combined impact of fire and dogs on the koala colonies at Port Stephens will increase as their coastal forest habitat becomes more fragmented and isolated by urban growth, placing the population at greater risk (Lunney et al. 2006).

Threats

Seven broad categories of threat are recognised worldwide as driving the loss of biodiversity (Millennium Ecosystem Assessment 2005a):

• habitat loss, fragmentation and degradation
• land degradation
• invasive species
• unsustainable levels of natural resource harvesting and extraction
• nutrient loading
• pollution
• climate change.

All categories are relevant to NSW (NPWS 1999).

Habitat loss, fragmentation and degradation is the most serious and widespread threat category. Population declines and loss of species can continue for decades or centuries after the initial threat. For every 100 hectares of southern woodland cleared, an estimated 1000–2000 birds can die (Olsen et al. 2005). Degradation caused by the spread of invasive species and changes in fire regimes can have profound effects on the composition and dynamics of native animal and plant communities (see Biodiversity 6.4 and Biodiversity 6.5). Invasive species include weeds, introduced pest animals and over-abundant native species which compete for habitat.

There is already evidence of climate change impacts on biodiversity, including effects on species physiology, distribution and the timing of life-cycle events (Saintilan & Williams 1999; Hughes 2000; Howden et al. 2003; Hughes 2003a; Hughes 2003b; Root et al. 2003; Thomas et al. 2004). Effects on the diversity of NSW fauna have included altitudinal and latitudinal shifts in species distribution, as well as behavioural changes, particularly in alpine and subalpine zones. Rising temperatures and a reduction in snow cover have resulted in the colonisation of alpine ecosystems by native and feral animals from lower elevations (Green 2003; Pickering et al. 2004). Vulnerable fauna include the mountain pygmy possum and the broad-toothed rat.

Trends in latitudinal shifts in species have been demonstrated for flying foxes (Tidemann 1999), birds (Baxter et al. 2001) and invertebrates. Some migratory bird species are arriving earlier in alpine areas (Pickering et al. 2004) and there have been changes in the timing and duration of the reproductive period of reptiles (Bull & Burzacott 2002).

Climate change is also expected to exacerbate other threatening processes (AGO 2003). It may enable invasive species to expand into new areas, such as the cane toad moving south along the coast. More frequent forest fires will reduce habitat for animals reliant on hollows in standing trees and logs. Species already affected by reduced water flows in regulated river systems are likely to be worse off due to declining water quality and the effects of climate change. The combined effects of widespread fragmentation and degradation of habitat, changed fire regimes and competition from invasive species are also likely to reduce the options for native species to adapt to climate change.

Twenty-nine key threatening processes are listed under the TSC Act, including clearing of native vegetation, alteration of natural flows, high frequency fire, predation by the European red fox, invasion by bitou bush, and human-induced climate change. Among the 13 recent additions to the list between December 2002 and April 2006 were:

• pests and feral animals (goats, pigs, deer, cane toads, yellow crazy ants and bumblebees)
• disturbance caused by humans (subsidence from longwall mining; removal of dead wood; marine debris and shark control programs)
• exotic perennial grasses
• exotic vines and scramblers.

The listings demonstrate the wide-ranging impact of threats. Land clearing is cited as affecting 619 listed threatened species while the combined impacts of invasive species affect 657 listed species. Over half of the listings involve threats from invasive species (Coutts-Smith & Downey 2006) (see Biodiversity 6.4 and Biodiversity 6.9).

Response to the issue

The most effective response to the conservation of threatened species, populations and communities and their habitats is their protection in the reserve system. The NSW Government is committed to building the State's reserve system and improving its representativeness (see Biodiversity 6.2).

The Threatened Species Legislation Amendment Act 2004 refines mechanisms in the TSC Act to conserve threatened species, populations and ecological communities and their habitats, and further integrates conservation into land-use planning decisions. Parallel amendments have been made to the Fisheries Management Act 1994.

The key areas of reform are:

• in urban and coastal areas, better integration of biodiversity values into strategic land-use planning, changes to the development assessment process and accreditation of flora and fauna consultants
• in rural areas, embedding of threatened species conservation in native vegetation protection to deliver a system of conservation incentives for landholders
• transparent prioritisation of actions for recovery and threat abatement through the Priorities Action Statement
• upgraded enforcement and compliance provisions
• establishment of expert advisory councils (the Biological Diversity Advisory Council and the Social and Economic Advisory Council) to advise the Minister for the Environment on the social, economic and biodiversity implications of listing individual species, populations and communities
• introduction of additional listing categories – critically endangered species and communities, and vulnerable communities – to bring the legislation into line with international and Commonwealth categories.

Before the recent amendments, the TSC Act required the preparation of a recovery plan for each threatened species, population or ecological community and a threat abatement plan for each listed key threatening process. However, as the number of threatened species listed under the Act grew, this approach became unwieldy and required review.

Instead of a statutory requirement to prepare a plan, a Priorities Action Statement for each listing will identify a prioritised list of all necessary recovery and threat abatement strategies and actions covering every listed entity. A status report on each threatened species, where information is available, and timetable for recovery and threat abatement planning will be prepared.

DEC has released a draft Priorities Action Statement for public comment. In addition, DEC has developed a new threatened species website which provides comprehensive ecological information, including photographs, drawings and distribution maps on the listed species, populations and ecological communities in NSW.

At June 2006, 73 terrestrial recovery plans had been approved: one for an endangered ecological community, three for endangered populations and 69 others covering 84 species (including six multi-species plans for 21 species and 63 single-species plans) (Table 6.8). An additional 27 recovery plans have been publicly exhibited covering 33 species (including two multi-species plans for eight species and 25 single-species plans). Over 320 plans are in various stages of preparation.

Table 6.8: NSW terrestrial recovery plans

Source: DEC data June 2006

Note: ^(a) Excludes species presumed extinct.

Recovery plans have been effective in assisting the long-term survival of many priority species. For example, recovery actions for the little tern have successfully increased their numbers in NSW (Keating & Jarman 2004), while the number of breeding pairs for Gould's petrel recovered to over 900 in 2004–05.

The NSW Government has provided $230,000 for a community-based survey to determine the statewide distribution of koalas and changes in their distribution over the past 20 years. The survey will assess the conservation actions for koalas under the recovery plan and the Priorities Action Statement. Other wildlife species being monitored are the brushtail possum, echidna, platypus, spotted-tailed quoll, wombat, wild dog/dingo, fox, deer and cane toad.

Understanding and managing threatening processes provides a cost-effective way of addressing the causes of biodiversity decline. At April 2006, a total of 29 processes were listed. Under the amendments to the TSC Act, the Priorities Action Statement will identify broad strategies and priority actions to address these threats. These could include preparing a statement of intent or a threat abatement plan, survey and/or mapping of threats, initiating control actions or entering into management agreements with land managers or owners.

Since 2003, threat abatement plans for the plague minnow (mosquito fish) and bitou bush have been approved. The success of these plans will be evaluated as part of a five-year review process. The plan for the red fox establishes priorities for fox control as well as monitoring programs to measure how priority threatened species respond to fox controls (NPWS 2001) (see Biodiversity 6.4).

The NSW Government is developing a biodiversity offset and banking scheme called BioBanking. The scheme aims to help slow the loss of biodiversity by applying offset conditions to development approvals or clearing consents. To be effective, BioBanking will need to ensure that environmental values that are lost through approved land-use changes or developments are offset in other areas to improve or maintain biodiversity overall. The scheme will consider impacts on biodiversity in economic and financial terms and should contribute to the establishment of a market value for biodiversity.

The NSW Greenhouse Plan 2005 has allocated $2 million to identify research priorities in the Climate Change Impacts and Adaptation Research Program in NSW. Several biodiversity conservation projects being funded by this program will examine the impacts and risks of climate change on bushfires, biodiversity, invasive species, aquatic ecosystems and the development of conservation planning tools.

The statewide natural resource management (NRM) targets relevant to this theme are 'By 2015 there is an increase in the number of sustainable populations of a range of native fauna species' and 'By 2015 there is an increase in the recovery of threatened species, populations and ecological communities'. There is a need for further data on a statewide basis to provide a full picture of progress toward the targets.

Future directions

New and innovative reforms and techniques are being introduced to enhance the conservation of biodiversity but it is still too early to assess their effectiveness in addressing issues that are pervasive and long-standing. In many cases significant trends will only become clear over a longer time frame, and it will require sustained commitment and perseverance to achieve results.

There has been a fundamental shift in focus from recovery of individual threatened species – an approach which is largely reactive – to more pro-actively addressing the threats to biodiversity and drivers of biodiversity decline. However, species-specific recovery actions may still be developed in cases where the only populations remaining are in highly disturbed habitat.

In conjunction, a greater emphasis is now being placed on endangered ecological communities rather than individual threatened species. This focus on species assemblages and threatening processes will maximise the benefits for all species, not only those that are listed as threatened.

The threat abatement plans that have already been developed establish a model for the future management of threatening processes. The Priorities Action Statement will establish priorities and provide overall guidance about where efforts should be directed, while monitoring threat abatement plans will enable programs to be refined to enhance the outcomes achieved.

The information that presently supports the listing of threatened species is not collected systematically and this may lead to distortions and imbalances in the listings. The new provisions that allow for strategic guidance of the assessment process and the NRM Monitoring, Evaluation and Reporting Strategy (see Appendix 2) should provide a more effective basis for establishing the status of species. This will support future monitoring and reporting requirements for SoE and NRM, and better target those species in real need of protection.

Greater research effort is required to better understand conservation and species dynamics, and their interaction with threatening processes and disturbance regimes to optimise conservation outcomes within different land uses and across the whole landscape. Further research on restoration ecology is also needed to ensure that structural diversity and habitat function are achieved.