Species-Specific Effects on Occupancy

Transcription

1 Species-Specific Effects on Occupancy Highway Proximity and Predator Playback AEC 501 Lina Aita, Emily Bruff, Khai Button, Colleen Grant, Kathryn Nilsson, Ana Rivera-Burgos

2 Study Aims NC Wildlife.org Obtain baseline count of species at the study site Wintering species in North Carolina Mixed deciduous forest Examine urbanization effects in Wake County, NC Highway infrastructure Avian community structure ncwildlife.org

3 Background Proximity to infrastructure (buildings, highways, powerlines, etc) negative impact on bird populations Stress, noise, barriers, habitat destruction, and fragmentation WRAL Increasing urbanization in Wake County Photo: Per Breiehagen Graph and data compiled by Anora McGaha

4 Background Changes in Avian communities Responses to urban infrastructure? Urban exploiter species (Palomino and Carrascal (2007) Success of Screech Owls in Suburbs (GIll 2007) Eastern Screech Owls prey on smaller birds

5 Predictions Eastern Screech Owl playback has the potential to increase or decrease occupancy & detection Detection should increases if species alarm call in response Occupancy should decreases if species hide/leave in response Proximity to I-40 in Wake Co. Counts/detection should be lower as proximity to I-40 increases Image Credit: Transport Quebec Not a screech owl, but it was near a highway.

6 Study Area Um stead State Park 5,000 acres of mixed deciduous forest Southern portion (study area) bordered by I-40 (yellow)

7 Study Area Um stead State Park Protected since 1934 Originally farmland Mixed hardwoods and pine Photo by Stephanie Haines Photo by Miguel Vieira

8 Study Area Schenck Forest Managed forest (NCSU) Adjacent to Umstead and I-40 Better proxy for natural forest Controlled burns Stratified forest

9 Methods Loblolly Trail 20 sample points, 3x Spaced 200m apart 5 minute unlimited radius N count

10 Methods 40 additional points were sampled by other groups Points in Umstead State Park and Schenck Forest

11 Occupancy data analyzed using Methods Coin toss to determine playback Sound recorded at each site with a sound meter Sarah Wolfe, February 2011 Sites sampled over 15 days 8 am to 11am Distance to I-40 calculated using ImageJ

12 Resul ts Detection and occupancy models were calculated for five species of birds Kevin Shea, VA, January 2009 Carolina Chickadee William Jobes, PA, January 2009 Tufted Titmouse Dawn Vornholt, GA, December 2009 Pine Warbler Kevin Shea, VA, January 2009 Carolina Wren Judy Howle, December 2008 Northern Cardinal

13 Resul ts Species Naive Occupancy Occupancy Lowest AIC Model Detection AIC Value AIC Weight Carolina Chickadee Distance to I Carolina Wren Eastern Tufted Titmouse Screech Owl Northern Cardinal Pine Warbler

14 Resul ts Species Naive Occupancy Occupancy Lowest AIC Model Detection AIC Value AIC Weight Carolina Chickadee Distance to I Carolina Wren Eastern Tufted Titmouse Screech Owl Northern Cardinal Pine Warbler

15 Resul ts Untransformed Betas Transformed Species Intercept Occupancy Detection Occupancy Detection Carolina Chickadee Eastern Tufted Titmouse ± ± a p= ± ± b p= Mean ± S.E.M.

16 Resul ts Significant (p<.001) negative relationship, but effect was small

17 Discussion Sound readings decreased with distance from I-40 Distance not correlated with the occupancy in 4 of the 5 most common species William Jobes, PA, January 2009 Ambient noise likely not an important factor affecting bird occupancy in study area Mobbing behavior of titmice (Hill 1986) Osprey being mobbed by starlings

18 Discussion Eastern Screech Owl playback not correlated with detection No effect on occupancy in 4 of 5 species Volume of playback may be insufficient to affect detection Boldness of urban birds Only auditory, not visual Newsteam Marvel Comics, 2012

19 Discussion Points most likely needed to be closer to I-40 Previous studies showed the greatest effect on mean species abundance is within 500 m of a disturbance (Benítez- López et al. 2010) 479m

20 Discussion According to Lynch and Whigham (1984), habitat fragmentation =species-specific effects Other factors: Tree stratum Pine abundance Floristic diversity Land area and isolation Results not easily explained due to complexity of bird behavior Copyright 2016 River Partners. All rights reserved.

21 Discussion Urbanization is also known to alter bird behavior, survivorship, and response to predators (Gill 2007, Lowry et al. 2011) Lake Crabtree County Park Umstead S.P. Morrisville development Schenck

22 Sources of Error Inconsistent noise Joggers/dogs Bicyclists RDU? Insufficient point separation? Double counting -> false positives Multiple independent observation assumption Broad range of times and dates Different conditions

23 Conclusion Overall the study provided little evidence of correlation between bird occupancy/detection and proximity to I-40 or Eastern Screech Owl playback. Need to perform further studies to derive conclusive data Account for edge effects and proximity to all major roads Error in data due to Inexperience identifying birds False negative, misidentification (false positives) Insufficient distance between sites

24 Literature Cited Benítez-López, A., R. Alkemade, and P. A. Verweij (2010). The impacts of roads and other infrastructure on mammal and bird populations: A meta-analysis. Biological Conservation 143: doi: /j.biocon Gill, F. B. (2007). Lifetime Reproductive Success - Life Tables. In Ornithology. 3rd edition. W. H. Freeman and Company, New York, pp Hill, G. E. (1986). The function of distress calls given by tufted titmice (Parus bicolor): an experimental approach. Animal Behavior. 34: Hines, J. (2016). PRESENCE V (software). USGS. Lowry, H., L. Alan, and B.B.M. Wong (2011). Tolerance of Auditory Disturbance by an Avian Urban Adapter, the Noisy Miner. Ethology. 117: Lynch, J.F., and D.F. Whigham (1984). Effects of Forest Fragmentation on Breeding Bird Communities in Maryland, USA. Biological Conservation 28: Palomino, D., and L. M. Carrascal (2007). Threshold distances to nearby cities and roads influence the bird community of a mosaic landscape. Biological Conservation 140: doi: /j.biocon Quay, T. L. (1940). The ecological succession of winter birds at Raleigh, North Carolina. M.S. thesis, State College of Agriculture and Engineering of the University of North Carolina.

25 Questions?