Species at risk: Alpine spiny crayfish

Feb 20, 2019 | Species at risk: Wildlife

Alpine spiny crayfish | Mark Jekobson | NatureMapr | CC BY 3.0 AU

Alpine spiny crayfish | Mark Jekobson | NatureMapr | CC BY 3.0 AU

Alpine spiny crayfish

Euastacus crassus
Endangered: IUCN RedList

Habitat loss, trampling and grazing of creek-side vegetation pose serious threats to the alpine spiny crayfish, resulting in a reduction of water quality and impacting on their food sources and habitat.

Sharp, hard, heavy hooves cause streambed and bank degradation, increases in sedimentation and murkiness, as well as increased nutrient concentrations in water, which can result in algal blooms, that further smother aquatic habitat.

Sediment deposits are considered harmful to young crayfish as they coat creek beds and fill spaces used for shelter, which would otherwise protect juvenile crayfish from predators. A survey of Gippsland spiny crayfish habitat found that populations of the South Gippsland spiny crayfish fell as the level of in-stream silt increased. This demonstrates that any increase in in-stream silt is highly likely to impact spiny crayfish populations.

Increased murkiness can have negative physical, physiological and behavioural effects on stream-dwelling animals and plants. The alpine spiny crayfish is particularly threatened – their slow growth rate and low fecundity renders them extremely vulnerable to drops in population numbers caused by habitat destruction.

As horses damage wetland and bog areas, habitat becomes compacted, incised and unable to retain water. Alpine spiny crayfish are highly dependant on reliable water flows and unable to survive desiccation of their habitat.

 

References

  • Koster, W.M., Raadik, T.A. & Kefford, B.J., 1999, Observations on the distribution, habitat requirements, and aspects of the biology of the Central Highlands Spiny Crayfish, Southern Victorian Spiny Crayfish and South Gippsland Spiny Crayfish. An Unpublished Report. Freshwater Ecology, NRE Heidelberg, Victoria.
  • Van Praagh, B., 2003. Action Statement: Alpine Spiny Crayfish. Flora and Fauna Guarantee Act 1988 No. 136. The State of Victoria, Department of Sustainablity and Environment.