Indicator: CO-01 Trends in selected groups of coastal and marine species and habitats

Data

Waterbirds, coastal shorebirds, island birds and seabirds

The "State of Australia's Birds" 2003, provides the following data on various species of sea and shore birds.

In relation to waterbirds, shore and island birds, the following species seem to be stable:

  • Pacific black duck: population stable
  • Banded stilt: population stable
  • Brolga: population stable
  • Freckled duck: population stable
  • Magpie goose: population stable
  • Radjah's shelduck: population stable
  • Montagu Island Wedge-tailed Shearwaters and Short-tailed Shearwater (on the east coast): vary widely but in recent years they have been relatively stable.

The following species are increasing, following a decline:

  • Australian subspecies (race) of Gould's Petrel: has increased rapidly following remedial action, to around 1000 petrels in 2001-2002. Young birds have been successfully translocated to Boondelebah Island.
  • Hooded plover (at Mornington Peninsula National Park): has increased reproductive success, and the population has recovered from an earlier decline.
  • Lord Howe Woodhen (found only on Lord Howe Island): has grown to an apparently stable population of about 200 birds.
  • Migratory wader species (red-necked stint, sharp-tailed sandpiper, red-capped plover and fairy tern): at the Coorong in South Australia have all declined but most now seem to be on the rise again.

The following species are increasing either their population or their range:

  • Green Parrot (on Norfolk Island): showing a marked increase in numbers.
  • Southern Boobook: has increased population.
  • Little Tern: in NSW, numbers seem to be increasing. Long-term monitoring of the same species at Gippsland, Victoria, reveals large fluctuations but general stability in the long-term.
  • Little and Fairy Terns: have expanded their range in Victoria and New South Wales.

The following species are declining:

  • Curlew sandpiper: still appears to be declining.
  • Eastern Curlew (in southeast Tasmania): has shown a steady long-term decline from the 1960s, to less than one quarter of former numbers. The Winter counts, which reflect the number of young birds entering the population, also show a consistent decrease.
  • Bar-tailed Godwit: shows a decline.
  • Common Greenshank: seems to show a slight decline.
  • Red-necked Stint: may also have decreased in numbers.
  • The Curlew Sandpiper: has decreased markedly in the Coorong of South Australia and a widespread decline is indicated by the national Birds Atlas.

One hundred and forty-two species of seabird occur in Australian waters. Seventy six of these breed and spend their lives in the region, and 34 are regular or occasional visitors. On Macquarie Island, the Wandering Albatross population has fluctuated since the 1800s but since 1994, the population has remained stable, at approximately 19 breeding pairs. The Red-footed Booby nest counts show no evidence of overall decline in nesting density since 1986.

Source: Olsen P, Weston M, Cunningham R,& Silcocks A 2003, The State of Australia's Birds 2003, Department of the Environment and Heritage, Canberra, viewed 9 May 2006, http://www.deh.gov.au/biodiversity/publications/birds-03/index.html.

Seagrass

Australia hosts 34 species of seagrasses in the shallow tropical and temperate inshore waters (more than half of the world's 60 species) and 11 of the world's 12 genera of seagrasses (Short and Coles 2001), as well as the world's largest seagrass bed (in Shark Bay in WA).

At the time of the data provided for the National Marine Atlas, total area of seagrass around Australia was estimated at 4,339,151 hectares. Changes in seagrass extent are not monitored at the continental scale.

Source: National Oceans Office 2004, National Marine Atlas, viewed 21 Aug 2006, http://www.oceans.gov.au/Non-fish%20Atlas.jsp.

Marine Atlas Areas in Hectares
Area of Seagrass 4,339,151
Area of Coral Reefs 10,773,527
  7,527,743
  3,118,145
  127,638
Aggregated area of As represented in NOO Atlas Data for 2005 Difference (NOO - new area - ie area that has been subtracted) Area of similarity 2005 as a % of NOO data
Humpback whales 16,813,738 16,146,437 667,301 96
blue whales 6,468,107 3,200,110 3,267,997 49
southern right whales 11,793,913 2,225,967 9,567,946 19
Total 35,075,758 21,572,514 13,503,244 62
 
Area where species or species habitat is likely to occur (Dugong) 50,607,209
Dugong Protection Areas (A) 414,382
Dugong Protection Areas (B) 222,740
Total Dugong protection areas 637,122
 
World Heirtage areas 44,754,964
Ramsar areas 8,001,010
Restered National Estate area 160,465
Summary Marine protected areas 64,803,076
Terrestrial protected areas 80,895,099
 
Summary Marine area by IUCN 71,800,510
Summary Terrestrial area by IUCN 80,895,099
 
Area of oil and gas fields that lies within 2005 Humpback whale areas 4,272
Area of oil and gas fields that lies within 2005 Blue whale areas 11,112
Area of oil and gas fields that lies within 2005 southern right whale areas 0
Total 15,384
 
Area of oil and gas fields that lies within 2005 whale area as a percentage of total whale area 0.1%
 
Number of oil wells in 2005 Humpback whale areas 126
Number of oil wells in 2005 Blue whale areas 50
Number of oil wells in 2005 southern right whale areas 3
Total number of oil wells all 2005 whale areas 179

Source: DEH, unpublished

The State of the Great Barrier Reef World Heritage Area report of 1998 concluded that, overall, human pressures do not seem to have caused major decreases in areas of seagrass. However, the report noted that this conclusion is drawn only from those areas where more than one seagrass habitat survey has been done. The survey methods used were not specifically designed to detect effects of human activity. Thus only very large impacts on seagrasses would have been detected by these surveys.

Source: Great Barrier Reef Marine Park Authority 1998, State of the Great Barrier Reef report of 1998, viewed 9 May 2006, http://www.gbrmpa.gov.au/corp_site/info_services/
publications/sotr/1998/seagrass_frame.html.

The 2004 State of the Reefs report concludes that, on the basis of available data, some seagrass beds have declined while others are increasing with more seagrass beds remaining stable. Across the Great Barrier Reef region, the changes observed in seagrass communities appear to be attributable to natural cycles of decline and recovery. At this time, there is little evidence of a widespread decline in the condition of the seagrasses of the Great Barrier Reef. Supporting data are not provided.

Source: Great Barrier Reef Marine Park AuthorityGreat Barrier Reef Marine Park Authority 2004, State of the Great Barrier Reef report of 2004, viewed 9 May 2006, http://www.gbrmpa.gov.au/corp_site
/info_services/publications/sotr/seagrasses/index.html.

The 2006 South Australian State of the Environment Report found that the area of seagrass along the Adelaide coastline had decreased, with 720 hectares lost between 1995 and 2002.

Source: SA Department for Environment and Heritage 2006, Coasts and the Sea - Health of the Marine and Coastal Environment, viewed 26 May 2006, S:E&SR2006_SoEDataCoasts_OceansindicatorsCO 01 Coasts and the Sea - Health of the Marine and Coastal Environment.htm.

Selected fish

Changes in population and distribution of fish are not monitored at the continental scale for any fish species. However some data are collected on the Great Barrier Reef. Although these data are not accessible, some insights into the condition of fish species in Great Barrier Reef World Heritage Area are provided in the State of the Great Barrier Reef World Heritage Area Report 1998. It notes that there are approximately 1500 species of fishes in this area alone. Community composition varies across the shelf with some species being restricted almost exclusively to inshore or shelf-edge reefs. Reef fish numbers vary considerably from reef to reef and from year to year as a result of fluctuations in recruitment. While larger fish tend to be more abundant on unfished reefs, there is no indication from various programs monitoring the effects of long-line fishing of any large-scale significant declines in targeted species.

Source: Great Barrier Reef Marine Park Authority 1998, State of the Great Barrier Reef World Heritage Area 1998 - fish, viewed 9 May 2006, http://www.gbrmpa.gov.au/corp_site/
info_services/publications/sotr/1998/fish_frame.html.

The 2004 State of the Reefs Report does not provide any update on this report on the status of Reef fish species.

See also Indicator: CO-16 Status of Australian fisheries  for information on the condition of commercially utilised fish species.

Mangroves

Australia has the highest number of species of mangroves in the world-39 of the world's 68 species (Spalding et al. 1997).

Remote sensing data have been analysed to show the current extent of mangroves across all jurisdictions. Analysis of changes in mangrove cover have not been undertaken.

Northern Territory has the most substantial area of mangroves 303,724, followed by Queensland with 285,826 and Western Australia with 176,279. NSW, South Australia and Victoria all have less than 50 000 hectares of mangroves.

Coral and coral reefs

At the time of the data provided to the Marine Atlas, total area of coral reef around Australia was estimated at 10,773,527 hectares. The Atlas also shows the continental area of coral reef, as at 2004, which is at low, medium and high risk from known threats. Threats in Australian waters are primarily low or medium. Changes in coral cover extent are not monitored at the continental scale. However some data are available from the Great Barrier Reef.

Source: National Oceans Office 2004, National Marine Atlas, viewed 21 Aug 2006, http://www.oceans.gov.au/Non-fish Atlas.jsp.

A 30-year study (on Heron Island in the southern Great Barrier Reef) found that coral cover can vary between 0 and 80% depending on the site. Another study, using annual surveys of inshore reefs, showed large fluctuations in coral cover and community composition from year to year in response to cyclones, freshwater flood events and coral bleaching. The extent of these impacts and recovery rate depended on the community composition present before and after the impact, and on environmental conditions.

A comprehensive survey of historical photographs dating back to 1893, undertaken by the Great Barrier Reef Marine Park (GBRMPA), has indicated that out of 14 reefs investigated:

  • six showed no obvious changes;
  • four showed decreases in hard coral cover; and
  • four showed decreases in coral cover only in certain areas.

Source: Great Barrier Reef Marine Park Authority 1998, State of the Great Barrier Reef World Heritage Area 1998 - corals, viewed 9 May 2006, http://www.gbrmpa.gov.au/corp_site/info_services
/publications/sotr/1998/coral_frame.html.

The 2004 State of the Reefs Report does not provide any update on this report on the status of coral.

Some data and discussion of coral bleaching can be found at Indicator: The impact of climate variability on selected species, habitats or ecosystems 

Kelp and kelp forests

Kelp forests occur in cold, nutrient-rich waters and are among the most biologically productive habitats in the marine environment. The 2003 report on giant kelp reports that data from all sources show an estimated total giant kelp area of 1311 ha comprising 345 beds. Kelp surveys in 1952 and 1986 showed a decline in size and number of kelp beds over 30 years to an area perhaps only 5% of the original area. In some areas the kelp decline continued into the 1990s, although there was a very slight recovery in some locations. Declines in kelp coincide with climatic conditions but recovery is variable. Over-exploitation of commercial abalone and lobster are thought to be implicated in kelp decline. No more recent data are available since the late 1990s.

Macrocystis pyrifera on the east coast of Tasmania

Macrocystis pyrifera on the east coast of Tasmania

Source: Edyvane, K. 2003, The Giant Kelp Report, viewed 9 May 2006, http://www.dpiwe.tas.gov.au/inter.nsf/Publications/HMUY-5TT2P6?open.

Source:

What the data mean

While all marine species play a role on the maintenance of marine ecosystems, some species, or groups of species, such as mangroves, corals and kelps provide habitat for such a wide range of other species that their condition can therefore be considered key indicators for the condition of marine biodiversity more generally. Other groups of species, such as birds and fish, that are relatively visible and comparatively high up on the food chain, can also be viewed as indicators for the effects of processes impacting on the marine environment more generally.

The data on coral and seagrass are primarily available from the Great Barrier Reef and therefore do not provide a comprehensive continental picture. On balance, in 1998, coral cover appeared to be declining slightly - but no more recent study of the same area is available to update this finding. Seagrass appeared to be fairly stable but again data are far from sufficient to draw this conclusion with any certainty.

Mangroves are declining in some places and expanding in others - but it is not clear at this time whether they are expanding at the expense of saltmarsh, freshwater wetlands, rainforests or other habitats.

Data on kelp forests are limited to the giant kelp. Giant kelp declined very dramatically, both in overall area and in number of beds, during the second half of the 20th Century and declines continued into the 1990s in some places with only very slight recovery in others. Again, more recent data are not available.

Even if recent and trend data on the extent of seagrass, coral, kelp and mangrove habitats were available at the continental scale, extent of a habitat is at best a surrogate indicator for the condition of that habitat. Habitat condition could, to some extent, be extrapolated from the species richness of the habitat, and the population trends of some of the resident species. Unfortunately, data on the species richness of even these limited habitat locations are unavailable.

If recent and time series data on species composition and richness of these habitats were available at the continental scale, they would need to be read in the context of periodic, especially climatic, fluctuations within and between species populations, and their relationship to periodic fluctuations between the habitats themselves. This would require base-line data on such natural fluctuations over time prior to the advent of significant anthropogenic pressures. These data have never been collected.

The fish data, from the Great Barrier Reef only, do not show a decline in any fished species - but the Reef Report makes it clear that "lack of data and uncertainties regarding natural fluctuations in populations and distributions of various species inhibit any meaningful assessment of species condition and the sustainability of various uses". These Great Barrier Reef data should be read alongside the Status of Australian Fisheries data which shows a steady increase in number of species considered to be overfished.

Of the bird species studied, 7 species appear to be stable, 7 are declining, 4 have declined but appear to be rising or stabilising again, and 5 have expanded either their population or their range in it at least one location. However, even the bird data, some of which are compiled at the national level, are difficult to interpret in the absence of a better understanding of natural fluctuations in populations, particularly between species utilising the same habitat.

What this means overall, for this indicator: Trends in selected groups of species and habitats, is that we can not, at this stage, even in the rare cases where we know changes are happening, be sure whether changes in either extent of the selected habitats, or in populations of particular species, are indicative of healthy or unhealthy changes for their supporting and supported ecosystems. A precautionary approach would suggest that if, on balance, in the context of a range of anthropogenic pressures, more species and habitats seem to be declining than expanding, it probably does not bode well for the condition of ecosystems more broadly.

On the basis of the very limited data found for this very narrow range of species, groups of species and habitats, in a narrow range of locations, the conclusion must be that, on balance, more things seem to be declining than remaining stable.

Data Limitations

Species and ecological communities are crucial aspects of marine biodiversity. As noted above, to know what is happening to them at a continental scale, we need indicators that show, in relation to each other, long term changes in number of species, and general numbers within each species, found across different habitats, taking into account seasonal and climatic fluctuations within and between species and habitats.

In the absence of comprehensive data of this kind, change in condition of particular groups of species, as suggested for this indicator, need to be read collectively as a single indicator.

It is important that the data for each different species or group of species not be read as indicators in their own right. Changes in numbers and distribution within an individual species are not very meaningful, even in terms of the health of the individual species, without information on the population and distribution required to maintain the resilience of the species.

They provide even less information about biodiversity more generally because they do not reflect on how various levels of population or distribution of any one species may affect, result from, or otherwise correlate to the condition of other species contributing to the ecosystem.

Even if these interactions were fully understood, we do not have sufficient historical data or understanding of ecological processes to know whether a major fluctuation between species is indicative of a natural, ecologically beneficial adjustment process within an inherently dynamic system, or a symptom of anthropogenic degradation.

At present the main indicators we have for the condition of species, habitats and ecosystems are indicators of the populations of a few particular species, and of the extent of a few selected habitats in a few particular locations. Most of the data on these species and habitat are too geographically limited and do not have sufficient time series to provide much information about the overall population trends (let alone condition) even of these few species, groups of species and habitats.

Issues for which this is an indicator and why

Coasts and Oceans - Condition of the ocean and coastal waters - Condition of species, habitats and ecosystems 

In the absence of any way of assessing the overall condition of species, habitats and ecosystems across all Australian coastal land and coastal and marine waters, considering the condition of a selection of key species, groups of species, habitats and ecosystems is probably the closest we can come to an indicator.

Corals, mangroves, seagrass and kelp forests have been selected as significant indicators for biodiversity generally because they are groups of species that also represent habitat for a wide range of other species.

Fish and bird species have selected because they are visible, well up in the food chain (and therefore vulnerable to pressures operating deeper in the food chain) and some measurement of populations of fish and bird species is undertaken.

Other indicators for this issue:

Coasts and Oceans - Contributions and pressures between the coasts and oceans and inland water - Effect of changes in inland waters on the coasts and oceans 

Changes to inland waters, such as nutrient or sediment loads, can place pressure on coastal and estuarine waters.

Other indicators for this issue:

Coasts and Oceans - Contributions and pressures between the coasts and oceans and inland water - Condition of species at the inland waters-oceans interface 

Changes in inland waters and coastal waters can each affect the species, habitats and ecosystems that live at their interface. Changes to the condition of coastal waters can place pressure on freshwater systems and visa versa. Change in condition of selected species that live at or close to the interface of freshwater and marine water systems, such as a coral species, a mangrove species, or a shorebird species, could be an indicator that a pressure is occurring and, in some cases (for example loss of an inland or ocean predator, or a change in water salinity), could indicate a change in the pressure and contributions operating between the two spheres.

Other indicators for this issue:

Coasts and Oceans - Contributions and pressures between the coasts and oceans and inland water - Effect of changes in coasts and oceans on inland waters 

Interface species can be affected by changes to inland waters arriving from the ocean, for example during sea surges, seawater intrusion into groundwater or rises in sea level.

Other indicators for this issue:

Coasts and Oceans - Contributions and pressures between the coasts and oceans and land - Effects of changes in the ocean on the land 

Changes in distribution and abundance of a range of selected species that live at the land-ocean interface may be indicative of changes arriving from either the ocean or the land, for example seawater incursion from the ocean or acid sulphate soils from the land.

Other indicators for this issue:

Coasts and Oceans - Contributions and pressures between the coasts and oceans and land - Condition of species at the land-ocean interface 

Land and coastal waters can each affect the species, habitats and ecosystems that exist at their interface. Changes to the condition of coastal waters can therefore place pressure on the land and visa versa. Change in condition of selected species, that live at or close to the interface of terrestrial and marine systems, such as a coral species, a mangrove species, or a shorebird species, could be an indicator that a pressure is occurring and, in some cases, for example loss of an inland or ocean predator, could indicate a change in the pressure and contributions operating between the two spheres.

Other indicators for this issue:

Coasts and Oceans - Contributions and pressures between the coasts and oceans and land - Effects of changes in the land on the oceans 

Changes in abundance and distribution of species living at the interface of the land and the ocean could be indicative of either changes arriving from the land, such as excess sediments or nutrients or acid sulphate soils, or changes from the ocean such as seawater influx.

Other indicators for this issue:

Biodiversity - Species, habitats and ecological communities - Conservation status of species and ecological communities 

As well as being indicative of the condition of the ocean (and the contribution of biodiversity to that condition), condition of selected key groups of species and habitats may be indicative of the condition of biodiversity. In the absence of any way of assessing the overall condition of species, habitats and ecosystems across all Australian coastal land and coastal and marine waters, considering the condition of a selection of key species, groups of species, habitats and ecosystems is probably the closest we can come to an indicator.

Other indicators for this issue:

Biodiversity - Species, habitats and ecological communities - Condition of marine biodiversity: Condition of species, habitat and ecological communities 

In the absence of any way of assessing the overall condition of species, habitats and ecosystems across all Australian coastal land and coastal and marine waters, considering the condition of a selection of key species, groups of species, habitats and ecosystems is probably the closest we can come to an indicator for condition of marine biodiversity.

Other indicators for this issue:

Biodiversity - Species, habitats and ecological communities - Species diversity 

Changes in populations and distribution of selected sentinel species may provide insights into loss of species diversity.

Other indicators for this issue:

Inland Waters - Response of biota - Wetland and floodplain communities 

Several of the species selected as potentially indicative of the condition of coastal and marine biodiversity more broadly are also indicative of the condition of wetland communities.

Other indicators for this issue:

Land - Contributions and pressures between the land and the ocean - Pressures of ocean change on the land 

Changes in the condition of species and habitats that live at the land- ocean interface (seabird and shorebird populations, mangrove and saltmarsh) may be indicative of changes in the pressures and contributions between the land and the sea.

Other indicators for this issue:

Land - Contributions and pressures between the land and the ocean - Condition of species at the land-ocean interface 

Land and coastal waters can each affect the species, habitats and ecosystems that exist at their interface. Changes to the condition of coastal waters can therefore place pressure on the land and visa versa. Change in condition of selected species, that live at or close to the interface of terrestrial and marine systems, such as a coral species, a mangrove species, or a shorebird species, could be an indicator that a pressure is occurring and, in some cases, for example loss of an inland or ocean predator, could indicate a change in the pressure and contributions operating between the two spheres.

Other indicators for this issue:

Further Information

Further information on Australian coral reefs can be found at the following sites:

Source: Samson CR and Edgar GL 2001, Use of sediment cores to document changes in coastal marine habitats since European settlement', Australian Institute for Nuclear Science and Engineering, Lucas Heights.