King Penguin breeding population at Heard Island.

Brief description

This indicator is no longer maintained, and is considered OBSOLETE.

INDICATOR DEFINITION
The size of the breeding population of King Penguins at Heard Island.

TYPE OF INDICATOR
There are three types of indicators used in this report:
1. Describes the CONDITION of important elements of a system;
2. Show the extent of the major PRESSURES exerted on a system;
3. Determine RESPONSES to either condition or changes in the condition of a system.

This indicator is one of: CONDITION

RATIONALE FOR INDICATOR SELECTION
The breeding population of King Penguins is related to resource availability (nesting space and food), behavioural mechanisms (immigration/emigration and breeding effort/success) in addition to climate change and human impacts such as fisheries. Monitoring breeding population and interpretation of the data provides information on changes in the Subantarctic ecosystem.

DESIGN AND STRATEGY FOR INDICATOR MONITORING PROGRAM
Spatial scale: Heard Island (lat 53 deg 06' 00.0" S, long 73 deg 31' 59.9" E).

Frequency: 2-3 years. Access to remote colonies and other logistical constraints do not permit annual visits.

Measurement technique: Each colony is visited and individual birds are counted from the ground by two or three personnel performing replicate counts. Further counts are obtained by oblique ground and aerial photography. All breeding individuals in a colony are counted. Considerations regarding disturbance associated with census visits are also incorporated into monitoring strategies. The lack of annual census data does not reduce the value of these long-term monitoring programmes.

RESEARCH ISSUES
The king penguin breeding population at Heard Island has increased at almost 20% per year since the late 1940s; other king penguin populations throughout the Southern Ocean have also increased, but not as rapidly. At present, there is no alternative hypothesis to that previously proposed, that these population increases are sustained by the enhanced availability of myctophids, the principal prey of king penguins (Woehler et al. 2001).

LINKS TO OTHER INDICATORS

Lineage

Progress Code: completed

Statement: This indicator is now OBSOLETE. These data are no longer archived in this location, and are therefore not up-to-date.

Censuses of breeding adults are performed and long term trends are determined. Integration with other long term datasets is currently underway through international collaborations, allowing comparison among sites at regional and ecosystem scales. Some analyses and their interpretations have been published (see references), and current analyses will examine population data as they are compiled.