J.M. Fischer, M.H. Olson, J.C. Everhart, K.C. Rose, C.E.

Williamson, and R. D. Vinebrooke

Factors influencing the distribution and abundance of Daphnia

middendorffiana in alpine lakes of the Canadian Rockies

Daphnia middendorffiana in fishless lakes

of the Canadian Rocky Mountains

• co-dominant crustacean species in fishless,

alpine lakes

• affected by temperature and DOM (which are

responding to climate change)

CDOM

Daphnia

Phytoplankton

Bacterial Production

HNAN, Ciliates

PNAN

UV

CDOM

Daphnia

Phytoplankton

Bacterial Production

HNAN, Ciliates

PNAN

UV

scr

een

I. Spatial distribution

II.Temporal Dynamics

III.Short-term experiment

IV. Implications

I. Spatial Distribution

Survey of 9 deep, fishless, alpine lakes in Yoho and Banff National Parks

http://www.pc.gc.ca/eng/docs/v-g/dpp-mpb/sec4/dpp-mpb4d.aspx

I. Spatial Distribution

p=0.04

p=0.11

Survey of 9 deep, fishless, alpine lakes in Yoho and Banff National Parks

p=0.74

II. Temporal Dynamics

Pipit Lake, Banff National Park

II. Temporal Dynamics

Pipit Lake, Banff National Park

No significant correlation with DOC or chlorophyll

III. Short term experiment to explore mechanisms

Hungabee • Contains Daphnia • Warmer, Higher DOM

Oesa • Daphnia absent/rare • Colder, Lower DOM

2 Incubation Sites

3 Water Sources

Hungabee water, Oesa water, DOM-amended Oesa water

11 day incubation at 0.5 m Measured juvenile growth rate of Daphnia, a metric highly correlated

with population growth rate (Lampert and Trubetskovia 1996)

2x3 Factorial Design crossing Incubation Site and Water Source 5 replicates per treatment

Incubation site

Incubation site

Incubation site p<0.001

Incubation site

Incubation site p<0.001

Water source p=0.005

Incubation x water ns

Incubation site

Incubation site p<0.001

Water source p=0.005

Incubation x water ns

I. Spatial survey

• positive effect of DOC

II. Temporal dynamics in Pipit Lake

• positive effect of temperature

III. Short-term experiment

• Effect of incubation site (Temperature and/or UVR)

• Effect of water source

• Not a simple effect of cDOM

Distribution and abundance of Daphnia middendorffiana in

alpine lakes of the Canadian Rockies

Daphnia = a powerful

indicator of biotic

consequences of

climate change in

alpine lakes

Climate-driven variation in temperature, precipitation,

treeline, hydrology

Key physical/chemical variables in lakes such as

water temperature, DOC, nutrients, water transparency

Daphnia presence/absence, abundance, and juvenile growth