Impact of Southern Pine Beetle Outbreaks on Wildlife Habitat Suitability

1. Impact of Southern Pine Beetle Outbreaks on Wildlife Habitat Suitability Maria D. Tchakerian1, Robert N. Coulson1, Jaehyung Yu1, and Forrest Oliveria2 1. Knowledge Engineering Laboratory, Texas A&M University College Station, Texas, USA 2. USDA Forest Service, Forest Health Protection, Pineville, Louisiana, USA

2. Impact of insects on forests on forest resources Timber production Biodiversity Recreation, etc. on forest conditions Abiotic Biotic Composition Configuration

3. Southern pine beetleDendroctonus frontalis (Coleoptera: Scolytidae) • Native Insect • Primary killer of pines • Thirty-day life cycle, with continuous adult emergence through much of the year. • Cyclic in nature • High populations killing new host species • Range expanding?

4. The number of years in which the southern pine beetle reached outbreak status since 1960 (USDA-FS 2004).

5. Growth and dynamics of southern pine beetle infestations

6. Goal To evaluate how changes in forest composition and configuration resulting from Southern Pine Beetle (SPB) herbivory impact the quality of wildlife habitats in a meso-scale southern forest landscape.

7. Study Area Bankhead National Forest Alabama

10. 1960’s Loblolly Stand

11. Early 2002 Loblolly Stand

12. P. taeda stand, Bankhead National Forest, Alabama • Forest Stand Conditions • Average dbh 30 cm • Average height 30 m • Canopy cover 85 % • Trees/hectare 890

13. Loblolly Stand after SPB

16. Ecological Succession in a Pine Forest Landscape (Modified from Holling 1991)

17. Methods Stand data (CISC Database andAlabama FVS-Ready FIA Database –inventory year 1990) Stand Simulation (Simulated Forest Growth to 2002 conditions using FVS Southern Variant, SVS) Scenario 1: No SPB (No SPB infestation and no silvicultural treatment) Scenario 2: SPB Infestation (SPB disturbance into the stands identified during the epidemic) Stand conditions without SPB Stand conditions with SPB

18. Methods Stand conditions (Scenarios 1 and 2) Habitat Suitability Index (HSI)Calculations at stand level Landscape Habitat Suitability (Aggregated HSI values for the stands) Landscape Pattern Analysis (Landscape metrics)

19. Habitat Suitability Index (HSI) Models • Developed in the 80’s to quantify impacts on habitats caused by water or land use changes • Published by the US Fish and Wildlife Service http://www.nwrc.usgs.gov/wdb/pub/hsi/hsiindex.htm • Simple, general, standardized • Based upon variables that can often be estimated

20. Management Indicator Species Selected Wild turkey Pine warbler Northern Bobwhite Gray squirrel

21. Habitat Pattern • Habitat Suitability Index maps created • HSI maps reclassified: • Class 0, HSI=0 • Class 1, 0 < HSI < 0.25 • Class 2, 0.25 < HSI < 0.5 • Class 3, 0.5  HSI < 0.75 • Class 4, 0.75  HSI  1 • FRAGSTATS 3.3 used to quantify attributes of each class

22. Pine Warbler HSI • To evaluate the habitat suitability for cover and reproduction, three habitat variables were used: • V1 = Percent tree canopy closure of overstory pines • V2 = Successional stage of stand • V3 = Percent of dominant canopy pines with deciduous understory in the upper one third layer

23. C C l l a a s s s s 3 3 C C l l a a s s s s 4 4 Pine Warbler Without SPB With SPB

24. Class 3 decreased by 37%

25. Gray Squirrel HSI • To evaluate winter food and cover/reproduction habitat: • Winter food • V1 = Percent canopy closure of trees that produce mast > 10 inches dbh • V2 = Diversity of hard mast producer trees • Cover and reproduction • V3 = Percent tree canopy closure • V4 = Average dbh of overstory trees • V5 = Percent shrub crown cover

26. Gray Squirrel Without SPB With SPB

28. Eastern Wild Turkey HSI(a more complicated example) • To evaluate summer food and brood; fall, winter, and spring food; and cover. • Summer food and brood habitat • % herbaceous canopy cover, average height of canopy cover, distance to forest cover types • Fall, winter, and spring food habitat • Number of hard mast producing tress/ha > 10 inches dbh, % canopy closure of soft mast producing trees, % shrub crown cover (food production, behavioral, and of soft mast producing shrubs)

29. Eastern Wild Turkey- Summer Food and Brood Habitat With SPB Without SPB

30. Class 3 increased by ~ 1280 %

31. Eastern Wild Turkey- Fall/Winter/Spring Food Habitat Without SPB With SPB

32. Class 3 decreased ~ 28% Class 4 decreased ~ 8%

33. Northern Bobwhite HSI • To evaluate winter food habitat suitability in forest cover types • % canopy cover of herbaceous food plants • % of ground that is bare or covered with a light litter • Number of pine or oak trees/ha >10 inches

34. Northern Bobwhite – Winter Food Habitat Without SPB With SPB

35. Class 3 increased ~ 55%

36. CONCLUSIONS • 1. Using stand data, the FVS, and the HSI we created maps that defined classes of habitat suitability in a meso-scale forest landscape for 4 wildlife species. • 2. Using data from SPB spots we evaluated the effects of an outbreak of the southern pine beetle on habitat suitability for the 4 species. • 3. Impact varied in predictable ways by species: • Pine Warbler habitat was destroyed. • Grey Squirrel habitat was not affected. • Wild Turkey habitat was affected both negatively and positively. • Northern Bobwhite Quail habitat was enhanced. • 4. The effect of the insect outbreak was to perforate the forest landscape which generally decreased habitat patch size, increased habitat patch density, increased habitat patch number, and reduced core area of habitat patches. • 5. Habitat for each species was always present within the national forests. Another dimension to the study will be an investigation of species movements in relation to dispersion patterns of habitat patches.

37. Critical Issues • Detailed pre and post spb outbreaks forest inventory data • Validation of results of habitat models vs. current data on wildlife species • Development of alternative methods to evaluate positive and negative impact of insect outbreaks on forests