Areas of Study

Trees
Birds
Cerulean Warbler
Wood Boring Beetles
Lepidoptera
Small Mammals
Bats
Salamanders
Eastern Box Turtle
Timber Rattlesnake
Human Dimensions

Forest Dynamics

Inventory plots are being installed to characterize the long-term, landscape-level changes in forest canopy structure and overstory recruitment by oak and other highly valued tree species in response to forest management. These plots will also allow spatial modeling of oak regeneration in response to overstory canopy and other environmental valuables, thereby linking local, seed dispersal mechanisms to the landscape pattern. Plots are installed across all treatment types on a 75 m by 150 m grid, linking them to avian inventories and, eventually, an associated dead wood inventory.

Project Investigators
Zach Lowe, Purdue University, lowez@purdue.edu
Mike Saunders, Purdue University, msaunder@purdue.edu

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Birds

Many species of songbirds that nest in mature forests of the eastern United States are declining, and it is thought that forest management activities may be part of the cause for the declines, but also may be part of the solution. For the past two years, field technicians under the direction of Dr. John Dunning of the Department of Forestry and Natural Resources have conducted surveys of breeding birds at the HEE study areas to establish the distribution and abundances of species across the sites. As timber is harvested on the sites in the coming years, we will be looking at how birds respond, not only at the specific sites where timber management is conducted but also across the larger spatial scales of the HEE project. With Melissa Malloy, a Master’s student within the FNR department, Dr. Dunning will focus initially on predicted changes in the distribution of common breeders across the study regions, but future study may also look at impacts on breeding success. Birds are surveyed with 10-minute point counts, during which field technicians record all birds seen and heard within 100 meters of permanently marked locations. While all birds are surveyed, some species are of management or conservation concern, and therefore are of special interest. These include migratory songbirds such as the Wood Thrush and Acadian Flycatcher, resident species such as Blue Jays that play important ecological roles as nest predators and acorn dispersers, and unusual birds such as the Worm-eating Warbler, a habitat specialist that breeds in the steep forested slopes of southern Indiana.

Project Investigators
John B. Dunning, Jr., Purdue University, (765) 494-3565

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Cerulean warbler

Dr. Kamal Islam and his students at Ball State University have been studying the Cerulean Warbler in southern Indiana for the past 7 years. This tiny migratory songbird of conservation concern has experienced long-term population declines on its breeding grounds during the past 40 years. We are trying to understand factors responsible for the decline of this species in Indiana. Although Cerulean Warblers are generally associated with mature forests, their territories are often characterized by canopy gaps. The presence of Cerulean Warblers in selectively-cut stands suggests that canopy gaps are likely an important habitat variable. Our main goal is to monitor response of Cerulean Warbler populations to silvicultural treatments. During 2007, we conducted bird surveys using fixed-radius point counts in all 9 management units with over 90 detections of Cerulean Warblers. In addition, we calculated territory sizes and measured vegetation characteristics both within and outside of the territory boundaries. We intend to sample again in 2008 before harvest, and then monitor response of Cerulean Warbler populations to various silvicultural treatments beginning in 2009.

Project Investigators
Kamal Islam, Ball State University, (765) 285-8847

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Wood boring beetles

Dr. Jeffrey Holland of Purdue’s Department of Entomology and his graduate students are studying the influence of different types of forestry management on assemblages of longhorned beetles. Some of these beetles are devastating pests of forest trees, while many others play important ecological roles by decomposing rotting wood, acting as natural thinning agents, and reducing fire fuel load. Understanding how the assemblages of species changes over time under different management techniques will allow us to both promote the biodiversity of those native species providing ecosystem services and limit economic losses from the few pest species. The beetles are sampled using arrays of four different types of traps that each have characteristics to attract certain types of beetle. Thirty-six of these arrays were used to sample the longhorned beetles for about one and a half months in 2006 and three months in 2007. The sampling arrays will continue to sample after the harvests to detect changes in the assemblages of beetles. This is a diverse beetle family and they have found 70 longhorned beetle species during this project so far.

Project Investigators
Jeff Holland, Purdue University, (765) 494-7739

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Lepidoptera

Dr. Keith Summerville’s goal for the first five years of the Hardwood Ecosystem Experiment is to test for the relative importance of direct and indirect effects of timber harvest on the moth species. While species that rely on oak species may be directly effected by removal of their host by logging, the broader impacts of timber harvest remain unclear. After the first year, Keith has identified upwards of 350 species and 5000 individuals of moths in Morgan-Monroe State Forest. To sample these species, he uses a battery-powered light that draws the moths in and traps them in a funnel capped bucket. Twenty of these traps were set for five different nights in the summer of 2007.

Project Investigators
Keith Summerville, Drake University (515) 271-2265

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Small mammals

Oak Mast Production and Acorn Removal
Oaks are notoriously variable in their production of acorns, and many organisms rely on acorns as a source of food. Dr. Robert Swihart, with the help of field technician Jeff Riegel, has been monitoring production of acorns by over 50 black and white oak trees since 2006. Mast traps will allow us to assess changes in production associated with harvest treatments, and whether changes occur differentially for the portion of a tree’s canopy adjacent to a harvest opening. Two mast buckets are placed under each tree, and the acorns are collected on a biweekly basis in the autumn months. Acorns collected in traps are x-rayed to determine whether they are infested by weevils, a major source of seed loss in some areas. Future work also is planned to monitor micro-climate at each site as a means of assessing physical factors affecting variation in acorn production.

Dr. Swihart is also studying the removal of fallen acorns to determine which consumers in the forest community are benefiting from this important food supply, how use varies with food availability and consumer density, and whether differences occur due to tree harvesting. A series of semi-permeable exclosures is used to restrict access to acorns by vertebrates of different size, from deer to mice. Future work may study the dispersal of acorns into harvest openings to improve our understanding of forest regeneration processes.

Small mammals
Small mammals are important but seldom-seen components of forest ecosystems. They play important roles as seed dispersers, seed predators, and food for larger animals. The Hardwood Ecosystem Experiment is studying the effect of forest management on small mammal populations and communities. Dr. Robert Swihart designed a study in which livetrapping grids were established at 32 sites during summer of 2007, and trapping will continue in summer 2008 to establish baseline population levels. Attributes of habitat also are being measured around each trap, in the area scheduled for harvest, and in each of the 900-acre management units, to enable us to assess whether certain attributes are consistently associated with use by small mammals. Beginning in 2009 we will evaluate the response of small mammal populations and communities to forest harvest and post-harvest silvicultural treatments.

Project Investigators
Robert K. Swihart, Purdue University, rswihart@purdue.edu

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Bats

Wildlife managers face a conundrum when asked to manage a species that requires a specific type of sub-climax habitat. If you remove the habitat, you lose the animal. Conversely, if you leave the habitat alone, it will become over-mature and eventually cause a decline of the species. This is the issue facing wildlife biologists and timber managers in Indiana where many of our species are dependent on Oak/Hickory forests. For many years, these forests have been allowed to grow without harvest or fire, and the result is that the understory of these woods is now filled with species such as maples and beeches that are the true local climax habitat.

For many species of wildlife, particularly game animals such as deer and turkey, we have enough scientific knowledge to predict the results of timber harvest on local populations. Such is not the case for the endangered Indiana bat (Myotis sodalis). Part of the problem is that these bats spend their summers in old dead or dying trees with loose bark. In these snags the females form large colonies (often with 100+ individuals) and raise their young. So biologists are very concerned that timber harvest will either remove the roost trees or the next generation of roost trees.

Although Indiana bats will use almost any large tree with sloughing bark and substantial solar exposure, oaks and hickories seem to be some of the better roosts because one dead tree will hold onto its bark for many years. Maples are rarely used and seem not to form high quality roosts, while no one has ever recorded an Indiana bat using a beech. Thus, we also face a situation that as oak-hickory forests become beech maple forests, they may become less valuable to bats. One way of turning back the clock on succession is by using timber harvest—the overall goal of Hardwoods Ecosystem Experiment is to determine the impact of harvest on a wide variety of wildlife.

To determine the impact of timber harvest on bats we are “trapping” bats in 2 ways. First, we are using mist-nets to capture them as they fly through an opening in the forest. This allows us to directly handle the bats and determine their age, sex, reproductive state, even if they have been captured before. Unfortunately, mist-nets are only effective when placed in an area, such as a roadway or stream, where bats are funneled into the net. Thus, they are not very good for detecting bats that are simply flying through, or over a forest. To “trap” these bats we are using a device called an Anabat® Detector that converts the echolocation calls of bats into an electronic file. Once these data are stored, we can go back and identify many of the calls to species. This technique allows us to “capture” many more bats, but we do not have the detailed information about the individuals such as we get from netting.

Project Investigators
Virgil Brack, Environmental Solutions & Innovations,Inc., vbrack@EnvironmentalSI.com
Dale Sparks, Indiana State University, dsparks@isugw.indstate.edu

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Salamanders

Terrestrial plethodontid salamanders are an ideal group of species to monitor forest ecosystem integrity and biodiversity across the eastern United States. They play a significant role in nutrient recycling by consuming vast quantities of invertebrates and in turn serve as prey items for other forest species. They are sensitive to environmental stresses, and they are often the most abundant vertebrates in deciduous forests. However our current knowledge of the effects of timber harvesting on salamander populations is incomplete. Most studies suffer from a lack of replication among various silvicultural treatments and focus solely on immediate post-treatment responses. The terrestrial salamander portion of the Hardwood Ecosystem Project is designed to evaluate the effects of timber harvesting on the diversity, abundance, and demographics of woodland salamanders. Beginning in May 2007, we placed a total of 66 coverboard grids (30 boards per grid) within the 9 study areas. The coverboard grids were checked every other week from September through November. A second year of pre-harvest data will begin in the spring of 2008 and will include nearly 2000 quadrat surveys (1x1m plots) in addition to the coverboard sampling. Beginning in 2009 and continuing through 2011, we will evaluate the immediate response of plethodontid salamander populations in regenerating forests < 5 years old. Planning is currently underway for the evaluation of long-term harvest effects (7-10 years post-harvest) on terrestrial salamander populations among the various harvest treatments.

Project Investigators
Rod Williams, Purdue University, rodw@purdue.edu

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Box Turtle

Recent research indicates that previously unnoticed declines in box turtle populations have become apparent across the country. What were often regarded as ‘good numbers’ in box turtle density, have been determined to be insufficient for healthy population growth and survival. Although Indiana does have a few healthy populations, these populations are widely scattered. Timber harvesting is a major land use activity throughout the range of this forest species that could impact turtle populations.

Our research is designed to evaluate the responses of box turtle home range and habitat use to even- and uneven-aged timber harvesting. Beginning in May 2007, we located box turtles in 6 research core areas (2 control, 2 uneven-age, 2 even-age) and subsequently tracked individuals 2-3 times per week through October 2007. Vegetation characteristics collected at a subset of turtle locations will be used to assess box turtle habitat use and selection.

Relatively high population densities of box turtles are required for successful reproduction. In 2007, we established two, 20-acre search plots within the each core area. Plots were searched for turtles 6 times to estimate local population densities within each plot. All data collected in 2007 and part of 2008 will serve as the baseline to compare to post-harvest responses.

Project Investigators
Brian MacGowan, Purdue University, macgowan@purdue.edu
Zachary Walker, Indiana Div. of Fish and Wildlife, zwalker@dnr.in.gov

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Timber Rattlesnake

Timber rattlesnakes have experienced population declines throughout most of their range. These population declines have been attributed to habitat loss, habitat fragmentation, and human persecution. Within Indiana, timber rattlesnakes have been listed as endangered due to extensive population declines. Although previous work has been preformed on the spatial ecology of this species within Brown County, no information exists on the effects of timber harvesting. This study will attempt to quantify the effects of timber management practices on rattlesnake movement patterns and habitat selection.

Beginning in May of 2007, surveys for timber rattlesnakes were preformed within core units where previous observations occurred. Nineteen snakes were observed as part of these surveys. A subset of captured rattlesnakes (6M:5F) were implanted with a radio transmitter and tracked 3 times a week throughout their active season. Radioed snakes are currently located on control and even-aged management units. All snakes were tracked to their respective hibernacula. The habitat selected by study individuals was quantified and will be compared to paired random habitat measurements. Data collected from 2007 will be used for comparison against post harvest snake radiolocations and habitat selection.

Project Investigators
Brian MacGowan, Purdue University macgowan@purdue.edu
Zachary Walker, Indiana Div. of Fish and Wildlife, zwalker@dnr.in.gov

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Human Dimensions

Project Investigators
Bill Hoover, Purdue University, billh@purdue.edu

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