Northern deciduous forest as wildlife habitat. Tom Paragi Alaska Department of Fish and Game Fairbanks

Transcription

1 Northern deciduous forest as wildlife habitat Tom Paragi Alaska Department of Fish and Game Fairbanks

2 Boreal food webs Pastor et al Biodiversity and ecosystem processes in boreal forest. Pages in Functional roles of biodiversity: a global perspective. John Wiley and Sons, New York. Deciduous forest provides cover and forage during early seral stages for mammalian herbivores and their predators, with increases in bird diversity as vertical structure and understory community develops (soft mast) Coniferous forest is dominated by invertebrate guilds and their avian predators while providing mast for rodents and herbivorous passerines (insects influence forest health)

3 Practical concepts of habitat Food, Water, Space, Cover, Arrangement Food (+ Space): ungulates require large changes in forage availability to cause population-level responses (e.g., survival) Cover + Arrangement : moose foraging in recent burns are less selective for preferred species with increasing distance from edge cover (implications for sale layout design)

4 Features of early-seral habitat (things to create when logging) Woody Forage (willow, aspen, paper birch, balsam poplar, cottonwood, red osier dogwood) Horizontal Cover (visual screen from avian and mammalian predators, wind screen) Vertical Cover (same as horizontal, plus shade) Herbaceous Vegetation (grazing forage, insect production for young birds)

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6 Practical concepts of habitat selection Habitat selection is a disproportionate presence of an animal in a habitat type compared to its availability Density of a species in a habitat type is another proximate means gauge importance, but it has drawbacks Fitness (survival and reproduction) is the ultimate demonstration of habitat quality when gauging land use practices, but it requires life-history studies (expensive)

7 Townsend s warbler Chugach Mountains study 1990s Birds nested in large white spruce trees in stands of dense white spruce Steve Matsuoka

8 Steve Matsuoka photos Nests placed in large trees experienced lower predation rates than nests in smaller trees Nests placed higher in trees also experienced reduced risk of larval blowfly infestation in nestlings than lower nests What proportion of the landscape contains these large trees?

9 Features of late-seral habitat (things to retain when logging) Snags and Cavity Trees: avian hunting perches, avian and mammalian nesting Large Woody Debris: grouse drumming logs, hollow boles and windthrown trees with root wads (mammal dens) (Generally bigger is better because of rarity at the stand and landscape scales) Lichen substrate in conifer stands: individual trees or patches of ground that provide caribou winter forage

10 Balance stand initiation treatments with retention of late seral features: Northern flicker (Robert Ott) How many, what size, where in stand?

11 Use empirical data for deriving operational guidelines on size or density of habitat features Permanent Sample Plots U.S. Forest Service (Forest Inventory and Analysis) University of Alaska-Fairbanks (Packee / Malone) Bonanza Creek LTER (Juday) Research Projects on stand structure Tanana Chiefs Conference (monitoring of riparian buffers, pre-commercial thinning, and overstory release harvests) U.S. Forest Service (individual scientists) ADF&G (snag/cavity survey in upland forest)

12 Modeling the effects of creating fuel breaks on snags and cavity trees in upland forest near Fairbanks to answer a forest management question: What density and size of snags, cavity trees, and spruce rust brooms would be lost with shearblading treatments (clearcutting)? ADF&G, ADNR, and UAF Forest Sciences Department field studies during 2005 and 2006

13 Study design and sampling protocol ADNR Forestry digitized stand typing from 1978 aerial photos Stratified random sampling in GIS by stand type (public lands <200 m from roads for access) Visited 75 sites across 9 stand types in 2005 Two 40x50m subplots (nested plots of width 10, 20, 30, 40m): Bate et al. 1999, PNW-GTR-425

14 Minimum sample criteria for availability 13 cm dbh for snag (pole wood) any tree with cavity opening in the trunk >2.5 cm in horizontal or vertical dimension and deeper than its least width dimension (penetration into the sapwood required) Cored 3 largest trees of living cohort, GPS location, digital photo, measured features by hand or with Relaskop (ground truthing potential for remote sensing) Many cavities could not be viewed without climbing (not a study objective)

15 Sampling plots near Fairbanks 2005

16 Mean stand Stand type Size class n sites age (yrs) white spruce saw white spruce pole* 1 -- black and white spruce saw / pole black spruce, birch, aspen saw 8 88 white spruce, birch, aspen saw white spruce, birch, aspen pole birch, aspen, poplar saw / pole conifer* / mix seed / sapling deciduous seed / sapling 6 --

17 Decid-s/s Snag density by stand type WS/PB/QA-s BS/PB/QA-s PB/QA/BP-s/p B&WS-s/p Con/Mix-s/s WS/PB/QA-p Stand age decreases from left to right WS-s Number / ha (95%CL)

18 Decid-s/s Number / ha (95%CL) Cavity tree density by stand type WS-s B&WS-s/p WS/PB/QA-s BS/PB/QA-s PB/QA/BP-s/p Con/Mix-s/s WS/PB/QA-p Stand age decreases from left to right

19 Cavity trees (all stand types combined, n = 283) frequency live tree hard snag soft snag dbh (cm)

20 Cavity height by tree diameter (n = 192) 20 cavity height (m) deciduous coniferous dbh (cm) Cavity opening by tree diameter (n = 187) 1200 cavity opening (cm 2 ) deciduous coniferous dbh (cm)

21 Shape and size of cavity openings by decay class (n = 187) cavity opening (cm 2 ) width:height live tree hard snag soft snag

22 Follow-up evaluations of draft operational guidelines are needed to confirm habitat quality Habitat selection studies (wildlife use of retained late-seral features compared to their availability in the larger landscape) Demonstrated fitness of animals using features (survival to breeding age)

23 Questions and Discussion Northern hawk owl