Long term dynamics of macro-invertebrate biological traits with climate change. Presented by Alexander Milner at the "Perth II: Global Change and the World's Mountains" conference in Perth, Scotland in September 2010.

1. Long term dynamics of macro-
invertebrate biological traits with
climate change.
Alexander M. Milner, Anne E. Robertson & Lee E. Brown

2. Glacier retreat
Most regions of the world have
seen decreases in glacial mass over
the last 50-60 years
Along the Gulf of Alaska, retreat
has been particularly extensive
and rapid
Here, ice sheet/glacier retreat
dates back to ~1750 (LIA)
Dyurgerov & Meier, 2005 - PNAS

3. 1892
Over 130 km spatial scale we have a 230
year temporal scale

4. Glacial river ecosystems
Glacier-fed rivers are cold, unstable
habitats typically dominated by
Chironomidae
Glacial stream ecosystem studies mainly
adopt space-for-time substitutes
But... Wolf Point Creek (Alaska) studied
annually since 1978  ice sheet has
disappeared, new stream has formed and
floodplain vegetated

6. 1972

7. 1993

9. Catchment glacial cover – 70-0% in 28
years
Significant water temperature increase
Significant turbidity (suspended
sediment) decrease

10. Macroinvertebrate succession

11. Progressive community change linked to deglacierization
0% Percent Glacierization 100%

12. Trait dynamics and functional diversity
The identity, abundance and range of species traits appears to be considerably
more important than species number in determining the effects of ‘biodiversity’
on many ecosystem functioning (Diaz & Cabido. 2001. TRENDS Ecol & Evol)
How does functional (trait) diversity change following deglacierization?
Trait database of Poff et al. 2006 – J.
N. Am. Benthol. Soc.)
-20 traits, 61 modalities
- four groups of traits: life history,
mobility, morphology and ecology
- binary coding
- mostly genus level designations

13. Trait dynamics and functional diversity

14. Trait dynamics and functional diversity

15. 1892
Over 130 km spatial scale we have a 230
year temporal scale

16. 0.1
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Stonefly Stonefly
Gull Lake Gull Lake
Wolf Point Wolf Point
Nunatak Nunatak
Reid Reid
None
Weak
Strong
Head of Head of
Tindell Tindell
Low (<1km)
High (>1km)
Ice Valley Ice Valley
Vivid Lake Vivid Lake
Oyester Oyester
Catcher Catcher
North North
Fingers Fingers
South South
Berg Bay Berg Bay
Adult dispersal
South South
Swimming ability
Rush Point Rush Point
Carolus Carolus
river river
changes
throughout
Glacier Bay
Longer-term
Space for time
35 to 220 years
of development

17. 0.1
0.2
0.3
0.4
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Stonefly Stonefly
Gull Lake Gull Lake
Wolf Point Wolf Point
Nunatak Nunatak
Reid Reid
Large
Small
Warm
Head of Head of
Medium
Cold/cool
Tindell Tindell
Cool/warm
Ice Valley Ice Valley
Vivid Lake Vivid Lake
Oyester Oyester
Catcher Catcher
North North
Fingers Fingers
South South
Berg Bay Berg Bay
South South
Rush Point Rush Point
Carolus Carolus
river river
Body Size
Thermal preference

18. Concept of filters
determining
community
structure at
different degrees
of glacierization
75% glacierization
0% glacierization

20. SUMMARY
Significant reductions in cold stenotherms, insects with
long dispersal distance and collector gathers over time in
Wolf Point Creek. No significant change in body size over
the 30 year period.
Over the longer 200 year term some increases in body
size and increases in low dispersal distance and strong
swimming ability.
Significant increase in functional diversity over 30 years in
Wolf Point Creek but then a levelling off despite continued
increase in taxonomic richness – functional redundancy
although taxa richness has increased?
Even though the taxa in stream communities shift with
climate change, the functioning within the community
may remain the same.

21. Acknowledgements
Elizabeth Flory
Kieran Monaghan
Ian Phillips
Amanda Veal
Mike McDermott
US National Park
Service.