"Rapture Hypothesis" Scenario

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"Rapture Hypothesis" Scenario

It’s the end of

the world as

we know it…

The “Rapture Hypothesis” Scenario

(…with apologies to REM)

It’s the end of

the world as

we know it…

It’s the end of

the world as

we know it…

• The planet heats up…

• Snowline rises…

• Alpine mammals are trapped…

• Unable to adapt physiologically ….

• Habitat changes…

• Many populations appear doomed to

disappear…

• But some may not ascend to the

heavens from the mountains

And I

feel fine!


Sierra Nevada/White Mountain Alpine Mammal

Study

• 7-10 year study

• Multi-species study

– Bighorn sheep

– Yellow-bellied marmot

– American pika

– Belding’s ground squirrel

– Golden-mantled ground squirrel

• Multi-scale

– Rangewide

– Regional

– Local

• Estimate:

– Occupancy

– Habitat associations

– Density

– Demographic rates

• Model:

– Resource selection

– Species distributions

• Climate

• Topography

• Vegetation

– Population dynamics

– Persistence

• Compare:

– Among species

– Among mountain ranges

– Temperature gradient


What Are Implications Of Potential Range Changes

Of Mammals On Vegetation States?

• Can mammals “manage their own

habitat”

• Functional group changes

– Changes in relative abundance

• Changes in distribution of

interaction strengths

– Herbivory granivory

dominated system

• Focus on interactions and

feedbacks between climate and

ecological/ecosystem processes

• Combination of observational,

experimental, and modeling

approaches

Strength

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

T

marfla ochpri spebel spelat

Species

Strength

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

T+1

marfla ochpri spebel spelat

Species


Remote Sensing Data

Climate Data

Transects

Point Counts

Habitat Sampling

Exclosures

Seeding

Project Linkages 2009 - 2012

Change In Land Cover Classes

(1972 - Present)

Mammal Density, Occupancy,

Habitat Associations

Grazing-Herbivory Experiments

(Pinus contorta & P. albicaulis)

Evaluate interaction

strength

Unadjusted

Mammal Niche

Models

Adjusted by RSF’s

Projected Meadow

Conversion Models

Unadjusted Adjusted for biotic interactions


• Distribution and abundance

data

– 18 variable-distance line

transects (616 km)

• Sierra Nevada

– N = 12

– 10 km

– Sampled 4 times

– 480 km

• White Mountains

– N = 6

– 1.4 – 7.8 km

– Sampled 5 times

– 136 km

• June-September

– 5 point count stations per

transect (N = 90)

• Sampled 3 times per season

Small Mammal

Survey Methods

Northern

Central

Southern

White’s


A Few (very) Preliminary Results & Next Steps

• Density

– No geographic pattern across

Sierra Nevada

– Density in White Mountains ≈3x

greater than Sierra Nevada

• 3.8 ± 0.4 km 2 vs. 13.6 ± 1.9 km 2

– Complex patterns of variation

• Occupancy

– (43.3 %) 45.9 ± 5.2 %

– Two-strata model

• Habitat associations

– > 91% of observations in

talus/meadow ecotones

• Next steps

– Demographic studies

– Integral projection models

Proportion

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

Ochpri

Dry Meadow

Wet Meadow

Talus

Vegetation

Individuals km -2

Forest

Other

24

22

20

18

16

14

12

10

8

6

4

2

0

Ochpri

High Medium Low

Region

SNV WM

Available

Used

Proportion

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

Ochpri

Meadow

Talus

Forest

Vegetation

PJ

Sage

Available

Used

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