Se ha denunciado esta presentación.
Utilizamos tu perfil de LinkedIn y tus datos de actividad para personalizar los anuncios y mostrarte publicidad más relevante. Puedes cambiar tus preferencias de publicidad en cualquier momento.

Thresholds In Songbirds In Relation To Early Seral Forest At Stand And Landscape Scales

704 visualizaciones

Publicado el

Thresholds In Songbirds In Relation To Early Seral Forest At Stand And Landscape Scales

Publicado en: Tecnología
  • Sé el primero en comentar

  • Sé el primero en recomendar esto

Thresholds In Songbirds In Relation To Early Seral Forest At Stand And Landscape Scales

  1. 1. Matt Betts, Tana Ellis Forest Ecosystems and Society, OSU Collaborators: Joan Hagar, Brenda McComb, Kevin McGarigal, Jim Rivers Thresholds in songbirds in relation to early seral forest at stand and landscape scales
  2. 3. Area decrease = ~40% Mean patch size decrease = ~35% Kennedy and Spies 2005 Biol. Cons. (1939)
  3. 4. Historical and future ES <ul><li>Paleo- &dendroecological studies + simulation modelging </li></ul><ul><li>‘ Very open’ + ‘Patchy open’ = ~6% of historical landscape (Nokala & Spies 2005, Ecol. Apps .) </li></ul><ul><li>‘ Early seral’ (<30 years) = 30% ~historical (Wimberly et al. 2000 Cons. Biol .) </li></ul><ul><li>‘ Diverse early succession’ projected decline by 100% from HRV (Spies et al. 2007 Ecol. Apps.) </li></ul>
  4. 7. <ul><li>“ Structurally and compositionally diverse early seral forest habitats are now the scarcest habitat in the region” (Thomas et al. 2006 – Cons. Biol.) </li></ul>
  5. 8. Orange-crowned warbler Rufous hummingbird
  6. 9. <ul><li>“ Structurally and compositionally diverse early seral forest habitats are now the scarcest habitat in the region” (Thomas et al. 2006 – Cons. Biol.) </li></ul>
  7. 10. Stand Structure ~
  8. 11. ~
  9. 12. <ul><li>Which songbird species are associated with early seral broadleaf forest? </li></ul><ul><li>Is the occurrence of these bird species influenced by landscape composition? </li></ul><ul><li>Are there threshold levels of broadleaf in stands/landscapes? </li></ul><ul><li>Is habitat change ‘driving’ pop. declines? </li></ul>
  10. 13. Habitat variable ‘x’(Stand or landscape scale) Betts and Villard 2009 – Cons. Targets. Betts et al. 2007 – Cons. Biol. Population size/ occurrence/ density
  11. 15. <ul><li>Authors of 14 studies contacted </li></ul><ul><li>Klamath Bird Observatory (southern OR) </li></ul><ul><li>McGarigal & McComb (Coast range) </li></ul><ul><li>Hagar et al. (Coast range) </li></ul><ul><li>Fontaine (Biscuit fire) </li></ul>Total N (after removing sites due to missing data) = 4375
  12. 16. 4375 sample points 127,164 bird detections 110 species
  13. 17. Gradient Nearest Neighbor (GNN) method for predictive vegetation mapping Regional forest survey + Remote sensing data + Imputation = spatial data
  14. 18. Coastal Oregon Oregon Attribute table (joined to ArcGIS grid) Each pixel, or ArcGIS grid cell
  15. 20. <ul><li>% Broadleaf </li></ul><ul><li>% Early seral broadleaf (<10 cm dbh) </li></ul><ul><li>Spatial extents: 150, 500, 2000 m </li></ul>
  16. 21. 2 km 0.5 km
  17. 22. p = exp (β0 + β1 x + β2( x – ψ)+) / 1 + exp (β0 + β1 x + β2( x – ψ)+) Segmented logistic regression: Muggeo (2003) Statistics in Medicine Threshold Detection
  18. 24. <ul><li>11/ 27 models showed threshold response </li></ul>Pacific-slope flycatcher Ranged broadly from 1.35 – 24.5%cc Betts et al. Ecol. Apps. In Press
  19. 25. <ul><li>Positive response to early-seral broadleaf by 8/12 species </li></ul>Coast Range Klamath LARGE REGIONAL VARIATION IN THRESHOLDS
  20. 26. GNN Species distribution performance: Mean AUC = 0.83 ± 0.002 s.e. Best spatial scale = 2000 m
  21. 28. Betts et al. Ecol. Apps. In Press
  22. 29. <ul><li>Positive influence of early and late seral broadleaf forest on many species </li></ul><ul><li>Population consequences may have already occurred </li></ul><ul><li>High variation in thresholds among species and regions </li></ul><ul><li>More research needed at stand and landscape scales (manipulations) </li></ul>
  23. 30. Stand Structure ~
  24. 31. Tana Ellis and Matt Betts Oregon State University Forest Ecosystems & Society
  25. 32. <ul><li>Does amount of hardwood cover within a stand influence </li></ul><ul><ul><li>occurrence of songbirds? </li></ul></ul><ul><ul><li>productivity of songbirds? </li></ul></ul><ul><li>Are there threshold levels of hardwood within a stand? </li></ul>
  26. 33. <ul><li>28 Douglas-fir plantations of the </li></ul><ul><li>central Oregon Coast Range </li></ul><ul><li>Aged 5 to 9 years old </li></ul><ul><li>Hardwood cover </li></ul><ul><li>gradient 0-35% </li></ul>
  27. 35. <ul><li>6,013 total net captures </li></ul><ul><li>Banded 4,639 </li></ul><ul><li>Recaptured 837 </li></ul><ul><li>53 species </li></ul>
  28. 36. <ul><li>White-crowned Sparrow n= 375 </li></ul><ul><li>Swainson’s Thrush n= 375 </li></ul><ul><li>Orange-crowned Warbler n= 370 </li></ul><ul><li>MacGillivray’s Warbler n= 362 </li></ul><ul><li>Willow Flycatcher n= 268 </li></ul>
  29. 37. <ul><li>Need to take into account number of individuals (using rarefaction) </li></ul>
  30. 39. Full model R 2 = 0.45 Foliage gleaners= 12.8% (SE=3.5) Model Wi AIC Δ AIC THRESHOLD SE Segmented 0.98 2.19 0.00 6.456 1.709 Linear 0.02 10.18 8.00 - - Hardwood threshold at 6.7 % (SE=1.6)
  31. 40. Adult orange-crowned warbler HY (juvenile) orange-crowned warbler
  32. 41. β SE t P (Intercept) -2.09 0.06 -35.44 0.000 Log(Hardwood) 0.08 0.03 2.84 0.009 β SE t P (Intercept) -2.017 0.077 -26.143 0.000 logHWD 0.058 0.037 1.586 0.125 AGE-HY -0.139 0.097 -1.429 0.165 logHWD:AGEHY 0.043 0.046 0.926 0.363
  33. 42. Migrant Bird Demography Nest success Juvenile survival Migratory survival Adult survival Overwinter survival Faaborg et al 2010 Ecol. Monogr.
  34. 43. <ul><li>Does nest success = ‘habitat quality’? </li></ul><ul><li>Do conditions at the nest influence subsequent juvenile survival? </li></ul>Nest success Juvenile survival
  35. 47. SWTH nest
  36. 49. SWTH nest
  37. 50. Fledgling SWTH with transmitter
  38. 52. What happened to fledgling #150.781?
  39. 53. <ul><li>22 juveniles tagged, 36% survived </li></ul><ul><li>68% of mortality occurred within first 8 days </li></ul><ul><li>Best predictors: </li></ul><ul><li>1. Hardwood during post-fledging period (HR: 0.88 [95% CI: 0.76-1.00) </li></ul><ul><li>2. Corticosterone in the nest (HR: 0.86 [95% CI: 0.71-1.04]) </li></ul>
  40. 54. Summary <ul><li>Bird distributions at stand and landscape scales are influenced by abundance of early seral forest </li></ul><ul><li>Demographic effects are apparent </li></ul><ul><li>This might be partly due to post-fledging survival on the breeding grounds </li></ul>
  41. 55. <ul><li>Manipulative study (funded by USDA) </li></ul><ul><li>‘ Top-down’ effects of birds on insect control </li></ul><ul><li>More extensive tests of thresholds </li></ul>
  42. 56. THANKS!

×