Changing Landscapes: Foodscapes

Kathy Parker, Bob White, Don SpalingerContributions: J. Cook, R. Cook, K. Denryter, M. Gillingham, D. Gustine, R. Lay

CARMA 9, Whitehorse, Yukon March 2018

• Landscapes are changing.

• Many caribou populations are declining.

• Which habitats are important to caribou, why, when, and how might they change?

D. Heard

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The role of food and nutrition

• Nutrition is the basis for survival and reproduction.

• Nutritional needs and foods change with season.

• Food matters on an annual continuum.

Fall

Spring

SummerWinter

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Vegetation classification from satellite imagery

Roberta Lay 2002 MSc ThesisGustine et al. 2006 Wildlife Monograph

Besa-Prophet Area, northern British Columbia

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June July

August September

Besa-Prophet Area, BC5

Index of vegetation biomass (NDVI)

Gustine et al. 2006 Wildlife Monograph

Average NDVI Values by Vegetation Type

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0.10

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0.50

June July August September

Month

ND

VI

Carex spp.ShrubsLow productvity spruceGravel BarPineSubalpine spruceSpruceRiparian spruceDry alpineMoist alpineBurned/disturbed

0 5 10 15 202.5Kilometers¯

July

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Index of forage quality (change in NDVI)

Gustine et al. 2006 Wildllife Monograph 0 5 10 15 202.5Kilometers¯

June - July

Average Change in NDVI by Vegetation Type

-0.30

-0.20

-0.10

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0.10

0.20

0.30

0.40

Shr

ubs

Bur

ned/

dist

urbe

dS

ubal

pine

spru

ceM

oist

alp

ine

Dry

alp

ine

Car

ex s

pp.

Pin

eLo

w p

rodu

ctvi

tysp

ruce Spr

uce

Gra

vel B

ar

Rip

aria

n sp

ruce

Cha

nge

in N

DVI

June-JulyJuly-AugAug-Sept+

-

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Resource selection strategies by caribou

• Food quality: Caribou select high-quality areas in spring

• Food quantity: Caribou move to areas with higher biomass in summer

• Trade-offs with other factors

• Food values are not explicit in selection models

Gustine et al. 2006 Wildlife Monograph

D. GustineD. Gustine

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Use of tame caribou as a habitat assessment tool

Bite rate, bite sizeDiet compositionForaging timeDiet quality – energy, protein

K. Parker

K. Parker

Denryter 2017 PhD ThesisDenryter et al. 2017 Canadian Journal of Zoology

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All biomass is not food for caribou

Denryter et al. 2018 NRESi Extension Note

˂50% of all understory biomass in northern BC is accepted food (selected + neutral species)

Selected forage: 78% of intake28 species

Alpine Spruce-Fir BlackWhiteSpruce Wetland

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How caribou make a living

• Highly selective foragers

• Forage in habitats with relatively high quantities of accepted food (deciduous shrubs, forbs, lichens) in summer

• Achieve higher intake rates on species with large bite masses

• Allocate substantial time to foraging

Denryter 2017 PhD ThesisDenryter et al. 2017 Canadian Journal of Zoology

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Selected habitats and vegetation types improve both intake rate and and quality of food

• Forage biomass can control food intake rate

• Selective foraging can increase digestibility by 15-35%

White and Trudell 1980

Denryter 2017 PhD Thesis

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Foodscapes of digestible energy and protein intake

Example caribou summer range (Denryter 2017 PhD Thesis)

Vegetation cover classesEnergy foodscape Protein foodscape

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Denryter 2017 PhD ThesisNational Research Council 2007

Caribou must move across the landscape and high-grade when foraging

Energy intake

Protein intake

Maintenance for Non-lactating Caribou30,104 kJ DE/day94 g DP/day

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Estimating food value on the landscape• Consideration of spatial accuracy and scale

• Habitat mapping– high-resolution and frequent satellite images – need to validate community composition

• Food value of mapped habitats – index of quantity: accepted biomass – index of quality: digestible energy and protein

• Example: Combining NDVI of known communities with adjustments for accepted foods and food quality to index changes in foodscape value

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Combining satellite imagery (NDVI) with intakes of digestible energy (DEI) and protein (DPI)

• Seasonal trend in potential digestible energy intake

• Seasonal trend in potential digestible protein intake

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101112

130 150 170 190 210 230 250 270

DPI

(g•k

g-0.7

5 •d-1

)

Calendar day

0

400

800

1200

1600

130 150 170 190 210 230 250 270

DE

I (kJ

•kg-0

.75 •

d-1)

Calendar day

Non-lactator

ShrubBurned/Disturbed

Subalpine

Moist alpineDry alpine

Carex

Example not corrected for accepted biomass16

Potential intakes compared to requirements for lactating caribou

• Potential digestible energyintake relative to high and low milk production

• Potential digestible proteinintake relative to high and low milk production

0

400

800

1200

1600

130 150 170 190 210 230 250 270

DE

I (kJ

•kg-0

.75 •

d-1)

Calendar day

Non-lactatorLactator highLactator lowShrubBurned/disturbedSubalpineMoist alpineDry alpineCarex

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101112

130 150 170 190 210 230 250 270

DPI

(g•k

g-0.7

5 •d-1

)

Calendar day

Example not corrected for accepted biomass17

Foodscapes change as landscapes change. Why do they matter?

• Influence movements and distribution of caribou

• Linked to the ability of caribou to be productive

• Changing landscapes begin to limit choices. – Climate and fires– Disturbance and developments (with access)– Pathogens

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Sensitivity

Adaptive capacity

ExposureCaribou

vulnerabilityPotential Impact

Links to vital ratesHerd productivity

Climate, disturbance

Foodscapes: a tool to better understand the effects of changing landscapes

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ncasi

Ministry of Forests, Lands, and Natural Resource Operations

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• Denryter, K.A. 2017. Foraging ecology of woodland caribou in boreal and montaneecosystems of northeastern British Columbia. PhD Thesis. University of Northern British Columbia, Prince George, BC, Canada.

• Denryter, K.L., R.C. Cook, J.G. Cook, and K.L. Parker. 2017. Straight from the caribou’s (Rangifer tarandus) mouth: detailed observations of tame caribou reveal new insights into summer-autumn diets. Canadian Journal of Zoology 95:81-94.

• Denryter, K.A., R.C. Cook, J.G. Cook, K.L. Parker, and M.P. Gillingham. 2018. Nutritional values of habitats for woodland caribou during summer. Natural Resources and Environmental Studies Research Extension Note 12. University of Northern British Columbia, Prince George, British Columbia.

• Gustine, D.D., K.L. Parker, R.J. Lay, M.P. Gillingham, and D.C. Heard. 2006. Calf survival of woodland caribou in a multi-predator ecosystem. Wildlife Monographs 165:1–32.

• Lay, R.J. 2002. Use of Landsat TM and ETM+ to describe intra-season change in vegetation, with consideration for wildlife management. Master of Natural Resources and Environmental Studies Thesis, University of Northern British Columbia, Prince George, BC, Canada.

• National Research Council. 2007. Nutrient requirements of small ruminants: sheep, goats, cervids, and new world camelids. The National Academies Press, Washington, DC, USA.

• White, R.G., and J. Trudell. 1980. Habitat preference and forage consumption by reindeer and caribou near Atkasook, Alaska. Arctic and Alpine Research 12:511-529.

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