Butterfly diversity and abundance in the prairies, disturbed grasslands, and forests of the Palouse

Acmon blue ( acmon)

Amy Pocewicz, PhD Candidate Department of Forest Resources, University of Idaho Presentation overview

• Resources important to

• families and species found in this area

• Research project overview and preliminary results Lorquin’s admiral • When and where to look for butterflies Why should we care about butterflies? • Pollinators

• Threatened by loss of host plants and pesticide use

• Beautiful species, fascinating life cycle California tortoiseshell

Why study them?

• Short generations respond quickly to habitat changes

• Well described & life histories

Arrowhead blue Butterfly life cycle

• As adults, most rely on flower nectar to maintain energy

• About 1% of eggs survive to maturity

• Larvae consume foliage from specific host plants

• Winter diapause

• A few well-known species (i.e. monarch, painted lady) migrate long distances Photo: Mario Maier Painted lady What butterflies need:

1. Larval host plants

2. Hiding places for pupae

3. Nectar plants and sap for adults

4. Minerals and salts for adults

5. Protection from wind

6. Plenty of sun

7. Overwintering sites

8. No pesticides

From: The Xerces Society www.xerces.org Butterfly families

• Skippers (Hesperiidae)

• Swallowtails and Parnassians (Papilionidea)

• Whites and Sulfurs (Pieridae)

• Metalmarks (Riodinidae)

• Brush-foots () Fritillaries, checkerspots, crescents, satyrs, admirals, monarchs, angelwings, tortoiseshells, painted ladies

• Coppers, Hairstreaks, and Blues () Skippers (Hesperiidae)

Arctic skipper

These two species and several others feed on grasses; some species feed on legumes Garita skipper Swallowtails (Papilionidea)

Anise swallowtail Photo: Peter J. Bryant Willow, aspen, alder, birch, others Pale swallowtail , other shrubs

Photo: Peter J. Bryant Western tiger swallowtail Apiaceae: Lomatium, cow parsnip, others Whites and Sulfurs (Pieridae) Sulfurs host plants: Legumes (Fabaceae) Whites host plants: mustards (Brassicaceae/Cruciferae)

Orange sulfur

Stella’s orangetip

Cabbage white Brush-foots (Nymphalidae)

• Spend winter as adults

• Out in fall and early spring

• Nectar on tree sap in fall, spring

California tortoiseshell Host plant: Ceanothus

Photo: Peter J. Bryant Mourning cloak Willow, aspen, other hardwoods Milbert’s tortoiseshell Urtica (stinging nettle) Zephyr angelwing Ribes (currants) Satrys (Nymphalidae)

Wood nymphs (mating)

Common ringlet

Larvae feed on native and non-native grasses Checkerspots and Fritillaries (Nymphalidae)

Northern checkerspot Great spangled fritillary Asters, other composites Zerene fritillary

Photo: Peter J. Bryant Chalcedon checkerspot

Penstemon wilcoxii Viola adunca Coppers and Hairstreaks (Lycaenidae)

Edith’s copper Sylvan hairstreak Rumex (sorrel) Salix (willows)

Western pine elfin Pinus (pines)

Photo: Jeffrey Glassberg Blues (Lycaenidae)

Tailed blue Spring azure Legumes: Vicia, Trifolium, Ocean-spray, ceanothus, Lathyrus, spiraea, huckleberries

Males looking for minerals in the mud

Lathyrus sp. Blues (Lycaenidae)

Acmon blue Legumes and Eriogonum

Arrowhead blue and Astragalus

Silvery blue Lupinus and other legumes Boisduval’s blue

Only one Lupinus species used per population; appears to use Lupinus sericeus in our area

Sub-species fenderi in Oregon is federally endangered (Fender’s blue)

Boisduval’s blue Icaricia icarioides ssp. pembina Lupinus sericeus (silky lupine) Eriogonum feeders

Photo: Paul A. Oppler Photo: James L. Cummins Square-spotted blue Sheridan’s green hairstreak

These species feed exclusively on Eriogonum ()

Sub-species of square-spotted blue in California is federally endangered (El Segundo blue) Eriogonum heracleoides Role of non-native thistles

• Mylitta crescent host plant

• Late summer nectar source; Fritillaries prefer thistles for nectaring

• California study: 34% of butterfly species Mylitta crescent oviposit or feed on non-native plants

Great spangled fritillary Butterfly density and diversity across contrasting forest-grassland boundaries: identifying scales of response to resource availability

Research questions

1. Are there differences in butterfly diversity and density between land cover types?

2. How well are forest butterfly diversity and density explained by forest canopy cover and host plants?

3. Does butterfly abundance across forest edges differ between edge types? Study area Latah County, Idaho

Potlatch

Butterfly sampling sites Land cover

Agriculture Moscow Forest Grassland Water Wetlands Urban Barren Land, Clouds Idaho GAP analysis land cover data, Scott et al. 2002 Sampling design

• 16 sampling sites

• Forests dominated by ponderosa pine and/or Douglas-fir

• Forest sites share edges with different types of land uses (4 sites/type): Agriculture edge

Agriculture Disturbed grasslands (i.e. CRP) Palouse prairie & Forest meadows Clearcuts

Clearcut edge Sampling design 3 sampling transects per site

100 m

Forest

Non-forest 50 m

• April – July 2004, 2005 • Each site surveyed 5 times per year • Temperatures at least 60°F, sunny Other measurements

Measured systematically within each sampling transect:

• Forest canopy cover

• Forest stand density

• Shrub cover, by species

• Understory plant cover, by species No. butterfly species by land cover type 20 15 s e i c e p s y l f r 10 tte u . b o N 5 0

Agriculture Clearcut Forest Grassland Meadow Prairie

Land cover type Forest butterfly observations ons i

at 80 v r e 60 obs y l f er t 40 but . o 20 N l a t o 0 T agriculture clearcut grassland prairie/meadow

Non-forest butterfly observations s n o ti a 80 v r e s b 60 o y l f r 40 tte u . b o 20 N l ta o 0 T agriculture clearcut grassland prairie/meadow 2. How well are forest butterfly diversity and density explained by canopy cover and host plants?

Forest canopy closure effect on butterfly observations

10

8 ons i at v r

e 6 obs y l f r e t 4 but . o N 2

0

20 40 60 80 100

Forest canopy cover (%) Forest observations: Mylitta crescent (thistle feeder) Non-forest observations: Mylitta crescent (thistle feeder)

20 20 s s n n o o i i t 15 t 15 a a v v er er obs obs y y l l f f r r 10 10 e e t t t t bu bu . . l No l No a a

t 5 t 5 o o T T

0 0 agriculture clearcut grassland prairie/meadow agriculture clearcut grassland prairie/meadow

Forest observations: Common ringlet (grass feeder) Non-forest observations: Common ringlet (grass feeder)

30 30

s 25 s 25 n n o o i i t t a a v v r r

e 20 e 20 s s b b o o y y l l f f r 15 r 15 tte tte u u . b . b o 10 o 10 N N l l ta ta

To 5 To 5

0 0 agriculture clearcut grassland prairie/meadow agriculture clearcut grassland prairie/meadow Forest observations: Spring azure (shrub feeder) Non-forest observations: Spring azure (shrub feeder)

14 14 s s n n 12 12 o o i i at at v v r r e e 10 10 s s b b o o y y l 8 l 8 f f er er t t t t

bu 6 bu 6

. . No No l l

a 4 a 4 t t o o T T 2 2

0 0 agriculture clearcut grassland prairie/meadow agriculture clearcut grassland prairie/meadow

Forest observations: Silvery blue & Boisduval's (lupine) Non-forest observations: Silvery blue & Boisduval's (lupine)

14 14 s 12 s 12 ion ion at at v v r r

e 10 e 10 s s b b o o y y l 8 l 8 f f er er t t t t

bu 6 bu 6

. . o o l N l N

a 4 a 4 t t o o T T 2 2

0 0 agriculture clearcut grassland prairie/meadow agriculture clearcut grassland prairie/meadow Across-transect abundance: agriculture Across-transect abundance: grasslands

14 14

12 12 ons ons i i t t a a 10 10 v v r r e e 8 8 obs obs y y l l f f r r 6 6 e e t t 4 4 but but . . o o N N 2 2

0 0

-50 0 50 100 -50 0 50 100

Distance from forest edge (5m intervals) Distance from forest edge (5m intervals)

Across-transect abundance: clearcuts Across-transect abundance: meadow/prairie

14 14

12 12 ons ons i i t t a 10 a 10 v v er er 8 8 obs obs y y l l f f

r 6 r 6 e e t t 4 4 but but . . o o

N 2 N 2

0 0

-50 0 50 100 -50 0 50 100

Distance from forest edge (5m intervals) Distance from forest edge (5m intervals) Summary

• Largest number of species in forest meadows; fewest in agricultural fields

• More observations in prairies/meadows than disturbed grasslands Pearl crescent • Butterflies show response to land cover types that reflect their host plants

• Almost twice as many observations outside of forests as within forests

• Forest canopy cover is important: Number of observations and species decrease with canopy closure When and where to find butterflies

• Most abundant May-August

• When weather is warm, sunny

• Prairies, grasslands, forest openings

• In areas with lots of flowers Arrowhead blue

• On or near their host plants

• Along creeks and old roads

Lorquin’s admiral Acknowledgements

Access to field sites: University of Idaho Experimental Forest and 9 private landowners

Field help: Kelsey Sherich, Sean Irby, Penny Morgan, Leigh Lentile, Carly Gibson, Chris Lorion, Jeff Manning, Max Nielsen-Pincus, Ryan Toohey

Graduate committee: Penny Morgan, Sanford Eigenbrode, Andrew Robinson, Katy Kavanagh

Funding: National Science Foundation IGERT Program and USDA McIntire Stennis Program Where to find more information

Books: Butterflies of Cascadia (field guide) Robert Michael Pyle, 2002

Butterflies of British Columbia (reference book) Crispin S. Guppy & Jon H. Shepard, 2001

Websites: North American Butterfly Association www.naba.org

Butterflies of North America (online field guide) www.npwrc.usgs.gov/resource/distr/lepid/bflyusa/bflyusa.htm