Effects of fire, extreme weather, and anthropogenic disturbance on avian biodiversity in the United States Anna M. Pidgeon1, Chad Rittenhouse1, Thomas Albright1, Volker C. Radeloff1, Curtis H. Flather2, Jeffrey G. Masek3 Roger B. Hammer4, Murray K. Clayton5, and Susan I. Stewart6 1Department of Forest Ecology and Management, University of Wisconsin-Madison, Wisconsin 2U.S.Forest Service Rocky Mountain Research Station, Fort Collins, Colorado 3NASA Goddard Flight Center, Greenbelt, Maryland 4Department of Sociology, Oregon State University, Corvallis, Oregon 5Department of Statistics, University of Wisconsin-Madison, Madison, Wisconsin 6U.S.Forest Service Northern Research Station, Evanston, Illinois

Introduction  Biodiversity can change substantially within one decade with no obvious pattern of increase or decrease  How much does local disturbance affect biodiversity? North American Breeding Bird Survey Avian species richness change 1990 – 2000

Objectives  Our overarching goal is to measure and predict the effects of disturbance on avian biodiversity  Objectives: Understand the effects of extreme weather (i.e., hurricanes and tornadoes, heat waves, and droughts), on avian biodiversity; Understand the effects of fire on avian biodiversity Understand the effects of human disturbance (i.e., specifically clearcuts, fragmentation) on avian biodiversity; and Test hypotheses regarding the effects of disturbance on bird species richness, similarity, and the abundance of selected common and rare species.

Remote sensing data

Year 1 focus: Hurricanes and Drought  Hurricanes cause substantial changes in local forest vegetation and thus bird habitat forecast to increase with sea surface warming regional scale effects on avian biodiversity unclear

Hurricanes  Does bird species richness change in areas affected by hurricanes?  Are changes consistent among guilds?

Breeding Bird Guilds  Habitat type Shrubland Woodland  Nest location On or near ground Midstory or canopy  Nest type Cavity Open cup  Migratory status Resident Short distance Neotropical migrant

Landsat Time Series Annual or biennial images from 1984 – 2005 Data from North American Forest Dynamics Project Selected 5 scenes with major hurricane events

d1d1 d2d2

Disturbed Forest

Woodland Guild EffectEstimate ± SEPr > F Intercept Period Distance to Hurricane Log(avgNDVI) Log(stdNDVI) Proportion Forest ± ± ± ± ± <.0001

Mean Richness of Woodland Guild

Species Nesting On or Near the Ground EffectEstimate ± SEPr > F Intercept Period Distance to Hurricane Log(avgNDVI) Log(stdNDVI) Proportion NonForest Proportion Forest Proportion Water ± ± ± ± ± ± ±

Species Nesting On or Near the Ground

Period (i.e. Hurricane) Effect for 4 of 9 Guilds  Habitat type Shrubland Woodland  Nest location On or near ground Midstory or canopy  Nest type Cavity Open cup  Migratory status Resident Short distance Neotropical migrant

Conclusions – Hurricanes  Hurricane effects were statistically significant, but only when accounting for forest cover, and other habitat variables  However, regional effects on avian richness were less than expected, and short in duration

Year 1 focus: Hurricanes and Drought  Droughts temporally and spatially diffuse frequency and severity may increase with climate change effect on birds not well understood

Questions  What indicator of the avian community is most responsive to drought?  Which habitat and migratory guilds are most affected by drought?

Drought metrics Standardized Precipitation Index (“rainfall”) - Interpolated from met. stations - For specific time period & scale - Scaled in terms of standard deviations from averages Standardized seasonal greenness (“greenness”) - Integrated growing season greenness from AVHRR NDVI - Scaled in terms of standard deviations from averages

rainfall

Similarity Avian abundance most correlated with rainfall

Grassland and water guilds most correlated with rainfall

Neotropical migrants and residents are correlated with greenness

Conclusions – Drought - Full year rainfall and greenness deviations were the most relevant measure of drought for birds - Abundance more sensitive than richness or community similarity - Water and grassland guild most related to rainfall deviations - Among migratory guilds, resident species may be more robust to lower than average greenness.

Conclusions – Overall - We need a better understanding of disturbance effects on biodiversity - Extreme events may be more important than changes in average temperature and precipitation - Our results show that disturbances are important predictors of avian biodiversity patterns - However, effects are context and guild specific