Population Ecology of Grassland Sparrows on
reclaimed grasslands
Evaluation of the Pennsylvania Sex-Age-Kill Model for
White-tailed Deer
Testing Assumptions of Distance Sampling to Estimate
Abundance of White-tailed Deer
Harvest Rates of Wild Turkey Gobblers in Ohio, New
York, and Pennsylvania
Modeling the impacts of hunting on the population
dynamics of the Red Howler Monkey, Alouatta seniculus
Effects
of Antler Restrictions on Yearling Buck Survival, Buck Harvests, and
Hunter Satisfaction in Pennsylvania
Dispersal Timing, Rates, and Distances of
Pennsylvania Black Bears
Population
Ecology of Grassland Sparrows on reclaimed grasslands
Jason M. Hill, Graduate
Research Assistant
Duane R. Diefenbach,
Advisor
Grasslands throughout the
United States have been lost at incredible rates, and most grassland obligate
bird species also
have experienced significant downward trends.
While the reasons for these declines are many, habitat loss has played a
substantial role. Grasslands in Pennsylvania, created through coal
surface-mining reclamation activities, provide an important habitat for
grassland birds: notably Grasshopper (Ammodramus savannarum) and
Henslow’s Sparrows (A. henslowii). These reclaimed grasslands, however,
are being lost to successional processes as woody plant species recolonize these
areas. Grassland sparrow abundance and fitness are thought to decline with
increasing woody vegetation; although this evidence is based on observation and
correlation and has largely been measured in grasslands with little woody
vegetation.
With these ideas in mind I
implemented a large-scale manipulative experiment in the spring of 2009 to
measure the influence of woody vegetation on the abundance and fitness of
grassland birds. After collecting avian baseline and vegetation data on eight
50-ac plots during 2009, we will remove all woody vegetation from half of those
plots during the winter of 2010. By monitoring these plots for the following two
years, I will be able to link habitat structure and composition with territory
shifts, return rates, nestling growth rate, survival, and changes in population
size. Finally, I will conduct multiple grassland bird surveys at hundreds of
grassland sites across western Pennsylvania. I will model occupancy rates and
develop a population estimate for grassland sparrows in western Pennsylvania.
Taking what we learn from the woody vegetation removal experiment, I will be
able to estimate the percent of grasslands in western Pennsylvania that contain
viable populations of grassland birds.
Evaluation of the Pennsylvania Sex-Age-Kill Model
for White-tailed Deer
Andrew Norton, Graduate Research Assistant
Dr. Duane Diefenbach, Advisor
Readily available harvest data is frequently incorporated
into models used to estimate abundance of game species. However,
appropriateness of parameter estimates and assumptions using these data is
rarely evaluated. This project uses data across 10 years from >1,500 VHF and
GPS collared white-tailed deer to provide parameter estimates and evaluate
methods used to estimate white-tailed deer abundance in Pennsylvania. In
addition, this project will estimate precision of population estimates.
Testing
Assumptions of Distance Sampling to Estimate Abundance of White-tailed Deer
David Stainbrook, Graduate Research Assistant
Dr. Duane Diefenbach, Advisor
This project is taking place at
Gettysburg
National
Military
Park and Eisenhower National
Historic Site in
Pennsylvania.
White-tailed deer (Odocoileus virginianus)
were captured from January-March 2008 using rocket-nets and modified
clover traps and fitted with ear tags and GPS-collars. Over the next two
years, I will perform 7 distance sampling surveys using transects
selected from existing roads within a 2862 hectare or 11 square-mile
study area that includes both the park and private lands surrounding the
park. I will be collecting intensive GPS locations from marked deer
during the distance sampling survey to model habitat use. Results from
this habitat-use model will allow me to estimate the proportion of the
population that was actually near roads during surveys, to quantify the
bias introduced when using roads, and to correct population estimates.
Harvest
Rates of Wild Turkey Gobblers in Ohio, New York, and Pennsylvania
Duane R.
Diefenbach, Principal Investigator
Mary Jo Casalena, Pennsylvania Game Commission
Michael Schiavone, New York Department of Environmental Conservation
Michael Reynolds, Ohio Division of Wildlife
This is a 4-year study in which male turkeys were fitted with regular
leg bands and reward leg bands to estimate harvest rates, survival
rates, and hunter reporting rates in New York, Ohio, and Pennsylvania.
Fieldwork began in 2006 and over 3,200 birds have been banded across all
three states. This study has shown that traditional butt-end bands have
unacceptable band loss rates (Diefenbach et al. 2009) and that some type
of locking band should be used. Data collection is completed as of July
2009 and currently data are being analyzed. A final report is planned
for December 2009.
Modeling the impacts of hunting on the population
dynamics of the Red Howler Monkey, Alouatta
seniculus
Ruscena Weiderholt, Graduate Research Assistant
Dr. Stephen Beckerman, Co-advisor
Dr. Duane R. Diefenbach, Co-advisor
The aim of this project is to develop a spatially explicit,
individual-based model examining the role of several landscape factors
in sustaining harvest rates on primate populations in hunted regions.
The model is examining factors influencing hunting sustainability,
population persistence, and population size in a landscape with both
hunted and unhunted areas using Alouatta seniculus, the red
howler monkey, as a case study species. The influence of several
variables on population persistence are being investigated including the
intensity of hunting and the proportion of total area dedicated to
hunted versus reserve areas. Unhunted, reserve areas have been
postulated to have an influential role in harvest sustainability, and
hold merit as a conservation tool for overharvested species. However,
reserve design can be difficult to test empirically; thus, we employed a
modeling study to further explore the role of the larger landscape level
factors and reserve areas in hunted landscapes.
Bret
D. Wallingford, Graduate Research Assistant
Dr.
Duane R. Diefenbach, Advisor
Antler restrictions are a deer management tool that
regulates the legal harvest of antlered deer to those with a minimum number of
points on one antler. Antler
restriction regulations can be used to manipulate the sex ratio and harvest rate
of antlered deer. Whereas antler
restrictions have been tried in other states, no research has documented their
effects on harvest rates of yearling bucks.
The purpose of this research is to implement a 3- or 4- points/side
antler restriction regulation, in different areas of Pennsylvania, and then
measure survival of protected antlered deer, changes in the antlered deer
harvest, and level of hunter satisfaction.
Centre and Armstrong counties will be used for the 3- and 4-point study
areas, respectively. For each of
three years, 100 male fawns will be caught on each area in winter using
drop-nets, dart guns, Clover traps, and helicopters and marked with ear tag
radiotransmitters or radiocollars. Survival
of each cohort of marked deer will be monitored through two subsequent hunting
seasons. Harvests will be measured
using the reported deer harvest from hunters and estimates of reporting rates
from hunters known to be successful. Hunter attitudes will be evaluated using mail surveys.
More details at the Pennsylvania Game Commission website here
Dispersal
Timing, Rates, and Distances of Pennsylvania Black Bears