Back in Time
Paddlefish
Frog and Toad Monitoring
Bird Monitoring
Timber Rattlesnake
Insect Inventory
Small Mammals
Grassland Grazing
Nest Invaders
Expanding Our Glades
American Chestnut
Fire
Japanese Grass
River Cane
Glade Communities
Lichen

Research in Bernheim

Bernheim's 12,000-acre research forest is the site of numerous studies by scientists and students.  For more information contact Bernheim's Natural Areas Department.

Global Change: Influences on Forest Communities
Scientists across the globe have become interested in studying the effects of people on the environment, more specifically the influence of Global Change. Researchers from the University of Louisville are currently investigating the response of forests to increases in nitrogen deposition, carbon dioxide and temperature. By doing so, they will be able to better understand how forests will adapt if current worldwide warming conditions continue as expected.

In order to predict the effects of these changes the Urban – Global Change – Forest Ecosystems lab (UGCFE) at U of L has investigated the differences between rural and urban communities. Essentially, urban forests present an example of increased nitrogen and carbon dioxide as well as higher temperatures in comparison to rural forests like Bernheim. The differences between urban and rural forests can be used to determine how even larger global changes will effect forest communities. Recent global change models predict that continued warming could change the geographic range of forests types typically found in Kentucky. Therefore, field measurements will focus on eight tree species typical to local forests and look at how growth, mortality, and recruitment vary with changing conditions.

Researchers at UGCFE tirelessly gathered data on Bernheim’s rural forests in the fall of 2003 – collecting hundreds of vegetation samples and photographs. Lab analysis of this data is currently underway to determine the results of all of the collected data . Bernheim will be sure to update this website on the results of the study so be sure to check in again soon!

Back in Time
Just try to imagine what Bernheim looked like before European settlement. What plants were there? How dense was the forest? What animals were present? These are just a few of the questions that Philip Scarpino and Greg Lindsey of IUPUI will be looking into in their study of the region around Bernheim. In order to catch a glimpse of what Bernheim was like during this time period they will search through such things as journals, deeds, property surveys, drawings, and paintings that were done during this time period. This project will provide much needed information about the state of Bernheim's Natural Areas prior to the intense human disturbance that followed European settlement. This information will allow researchers to shape their management goals in a way that is consistent with the pre-settlement profile of the region. By reading through these early journals, deeds, etc., researchers can find suggestions of what the landscape was like. For example, a traveler's journal might give references to the plants or community types present, or a deed might describe trees or creeks that defined a boundary. Some specific information that Bernheim is interested includes the prevalence of native grasslands and the abundance of American Chestnut in the oak forest.

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Paddlefish Project
Bernheim is working with the Kentucky Department of Fish and Wildlife Resources to determine the growth and survival rates of paddlefish in Bernheim lakes.

Researcher Steve Mims, shown here with a mature paddlefish, caught several recently (October 2002) for evaluation purposes.  Originally, 50 one-pound paddlefish were introduced into Mac's Lake, and another 25 into the Cedar Lakes in early October 1996.  Paddlefish are noted for having eggs (roe) that rival caviar (from the related fish, the sturgeon). The purpose of this project is to test the feasibility of establishing an industry to raise paddlefish for both roe and for its flesh.

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Frog and Toad Monitoring
Declines in populations of frogs and toads have been observed world-wide. The reasons for the declines are not understood, but scientists speculate that pollution, predation by introduced species, habitat destruction, and climatic changes have contributed to the decline. Some declines may be the result of natural fluctuations of populations.

In order to coordinate efforts to monitor and understand the declines in native amphibians, an international group of biologists created the North American Amphibian Monitoring Program (NAAMP). In Kentucky, the "Frog Logger" program was recently established to assess the status of frogs and toads across the state using methodology that was established by NAAMP. The Frog Loggers program uses volunteers to visit sites at several times during the breeding season and record the species of frogs and toads that are heard calling. The Kentucky data is sent to NAAMP so that nationwide trends can be analyze.

At Bernheim, a series of ponds were created throughout the Research Forest to assist with fire control. These ponds have become hotbeds of amphibian activity. Two volunteer Frog Loggers are visiting the ponds during the breeding season and tracking all the frogs and toads that can be heard calling. This survey will provide Bernheim with important information about the species of frogs and toads that are present and where they are found. Bernheim will be able to provide the Frog Logger program with information on species that are present at a relatively undisturbed site.

If you are interested in volunteering for the Frog Loggers contact Mark Gumbert 606-625-0682 or Joe Settles at 606-245-7291.

Frog Monitoring Update
Thirteen species of frogs have been observed at 20 of Bernheim’s ponds since monitoring began in March, 1999. Only one of the 20 ponds had no frogs at all during the sampling period – the lack of frogs may be connected to the fact that there has been no water in that pond since July! Given the severe drought conditions this summer, it will be interesting to compare this season’s results with next year, if we have more rain! Reports on Bernheim's frogs are made to a froglogging net work on the National Wildlife Federation's website. Click here to see our data.

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Bird Monitoring
Neotropical song birds are a group at risk, and the decline in numbers of these birds is a grave concern to bird-lovers world wide. It is vital that we begin to carefully monitor these and other non-game birds to help understand the reasons for the declines and develop a plan to protect the species.

Bernheim has been involved in a long-term project that monitors changes in nongame birds at the site. The study uses methods that have been developed by Partners in Flight, a multiagency group that is committed to conserving birds and their habitats across the Western Hemisphere. By using this standard methodology, the data from Bernheim can also be used by Partners in Flight to analyze trends in bird populations throughout this hemisphere.

The diverse habitats at Bernheim support a diverse array of birds, over 200 species are known from the site, 33 of the species are on Kentucky’s list of rare species. An additional 15 of the bird species known from Bernheim are on the Partners in Flight Watch List. The watch list includes species that Partners in Flight have determined to be in need of conservation action.

Data from the first year of this bird monitoring program formed our baseline. We will be able to compare future results to this baseline to determine if certain species are increasing or declining over time. Detecting a decline in a species will allow us to take action to protect the species both here at Bernheim and throughout the species’ range.

Bernheim Bird Survey Update
More than 200 bird species are known from Bernheim. While many birds remain at Bernheim year-round, others are found only during the spring and summer, retreating to Mexico, Central and South America, and the Caribbean for the winter. Birds that breed in North America, and winter in the tropics are known as neotropical migrants.

The names of the neotropical migrants are almost as colorful as the birds themselves – some of the species that nest at Bernheim include – Blue-gray Gnatcatchers, Common Yellowthroats, Worm-eating warblers and Yellow-breasted Chats.>

Neotropical migrants have declined rapidly over the past several years – most likely due to destruction of habitat both in the tropics and in North America. Many of the neotropical migrants require large forested tracts to breed. Of the more than 400 species of neotropical migrants, 150 of these species are showing significant population declines – some species declining as much as 75%. This summer, Bernheim began a long-term project that will monitor changes in the number of bird species at the site. In this first year of the study 42 different species of birds were observed in the study sites. Almost half of the species seen (19) were neotropical migrants. To compare these results with nearby sites, Jefferson County Memorial Forest found 56 bird species (50% neotropical migrants) during a 1998 survey. A similar survey completed at Ft. Knox in 1998 recorded 52 different species (54% neotropical migrants).

Brown-headed Cowbirds also threaten neotropical migrants. This species was originally known from the open prairies west of the Mississippi; however, it also thrives in cleared forests and old fields. As forested land was cleared, Brown-headed Cowbirds increased dramatically in numbers and spread into the eastern U.S. Cowbirds lay their eggs in the nests of songbirds, reducing the number of songbird fledglings that survive. During this year’s survey, Cowbirds were found in 1/3 of the study sites. Bernheim is already changing management in the Research Forest to help control the impact of Brown-headed Cowbirds on neotropical migrants. We are no longer mowing wide strips along the roads within the Research Forest – this will reduced the open edge habitat where the cowbirds thrive.

Data from the first year of this bird monitoring program will be our baseline. We will be able to compare future results to this baseline to determine if certain species are increasing or declining over time. Detecting a decline in a species will allow us to take action to protect the species both here at Bernheim and throughout the species’ range. Bernheim’s monitoring will use methods that have been developed by Partners in Flight, a multiagency group that is committed to conserving birds and their habitats across the Western Hemisphere. By using this standard methodology, the data from Bernheim can also be used by Partners in Flight to analyze trends in bird populations throughout this hemisphere.

NEOTROPICAL MIGRANTS FOUND AT BERNHEIM DURING 1999 SURVEY

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Life History Notes on the Timber Rattlesnake in Kentucky (by William McMahan)
The timber rattlesnake or Crotalus horridus is a large viperid found in the eastern and east-central portions of the United States. A five year examination began in 1999, ended in 2003 and provided data on average weights, length, a ratio of 2:1 male/female, and dietary information.

Rattlesnakes were collected along roadways in the forest and when conditions were correct for easy capture. Each location was marked with vinyl flagging and the position coordinates recorded with a hand-held Global Positioning System (GPS). The snakes were then transported to the Louisville Zoo and implanted with a radiotelemetry device, then brought back to Bernheim and released where they were captured. The rattlesnakes were then tracked by radiotransmitters that included a temperature sensor inside of each unit.

Timber rattlesnake in Kentucky normally hibernate alone, three pairs of male and female rattlesnakes who were found in mating situations did not overwinter together. The active season for a timber rattlesnake corresponds closely with the frost-free period, typically between mid-April and late October. In late July is when the breeding behavior begins and continues into August. A close look at 22 of the male rattlesnakes found at Bernheim conclude that the average length of male snakes to be 114 cm, and the average weight to be 1223 grams. The diet of male snakes consists mostly of large rodents including squirrels, while the diet of female and small male snakes consist mainly of smaller rodents such as mice, chipmunks, and the occasional bird.

Historically the timber rattlesnake occurred in forests from southeast Minnesota and southern Maine to the Gulf of Mexico and into Texas. Unfortunately because of man the timber rattlesnake is now only found in large tracts of deciduous forest, which makes Bernheim Forest the perfect home.

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Insect Inventory
Studies of several groups of insects were completed at Bernheim during the 1970s ; however, much more work is needed to understandthe diversity of insects present within the Arboretum and Research Forest. Dr. Charles Covell Jr., Professor of Biology and Curator of the Insect Collection at the University of Louisville, initiated an inventory of the insects of Bernheim.

In order to identify as many different species as possible, sampling sites were be located in at least 15 different locations representing different habitat types within the Arboretum and Research Forest. A variety of sampling methods was used including aquatic collecting, light trapping, aerial and sweep netting and pitfall trapping.

An emphasis was placed on locating and identifying any rare insect species that may require special protection. Because prescribed fire will be used in management of the grasslands and woodlands of Bernheim Forest, it is particularly important to discover if any rare, fire sensitive species are present. If rare, fire sensitive species are found, more detailed monitoring of those species will be initiated and prescribed burn units will be designed to protect these species. This study also identified pest insects that may threaten both the native species of the Research Forest as well as the display plants within the Arboretum.

1999 Insect Survey Update

Species discovered that were not previously known from Bernheim. 

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Small Mammals
Human disturbances create a need to actively manage the natural areas at Bernheim. Our effect on such things as species diversity and environmental quality are a direct result of our past, present and future actions. In order to conduct the appropriate management within the natural areas, information must be gathered on all aspects of the forest. As part of this inventory of Bernheim’s natural areas John Palis, a local zoologist, has conducted a small mammal study of Bernheim.

In his study, John catalogued the ground dwelling small mammal community consisting of shrews, moles, mice and voles. These small mammals are often ignored due to their size and secretive behavior, but are actually a key component of natural systems. Their impacts can be seen on such things as soil fertility, nutrient cycling, plant species diversity, and seed dispersal.

In order to trap these sly and sneaky species, snap and pitfall traps were used. The sites were bated for four months, each consisting of four consecutive nights of trapping. A total of five sites were sampled, each of which was a prominent natural community type within Bernheim. The results of this study produced three new species of mammals not formerly known to exist within Bernheim. Overall the results were typical for the habitats sampled. Most species were found in the old field site and reduced in number through the oak slope, flat oak site, floodplain, and ending with the beech maple forest.

By collecting this baseline information Bernheim will be able to monitor changes in the small mammal population over time. Variations within the small mammal population can be key indicators of changes in the entire forest ecosystem. Future fluctuations in numbers of small mammals will be further evaluated to determine their root cause. This will allow researchers to shape their management in a way that best serves the community as a whole.

Small mammals found within Bernheim:

Peromyscus leucopus – white-footed mouse 
Microtus ochrogaster – prairie vole 
Microtus pennsylvanicus – meadow vole 
Microtus pinetorum – pine vole 
Reithrodontomys humulis – eastern harvest mouse* 
Synaptomys cooperi – southern bog lemming shrew*
Zapus hudsonius – meadow jumping mouse 
Cryptotis parva – least shrew
Sorex fumeus – smokey shrew
Sorex hoyi – pygmy shrew
Sorex longirostris – southeastern shrew*
Blarina brevicauda – northern short-tailed
* indicates species new to Bernheim

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Grassland Grazing
The natural areas of Bernheim have not escaped the disturbances caused by humans. Our actions involving such things as agricultural land use, restriction of fire, introduction of invasive exotic species, and disturbances of hydrology have caused changes in species diversity as well as ecosystem function. Bernheim’s natural areas have been shaped and changed by our past, present and future actions. These disturbances have made such a deep impact that it requires us to actively manage the forest in order to attempt to counteract some of these influences.

As part of this management process, Bernheim's natural areas staff are working to restore many native grasslands to the area. It is believed that there were hundreds of thousands of acres of grasslands in Kentucky at the time of the Native Americans. These areas were maintained through the use of fire in order to attract game and create habitat for the wildlife that Native Americans depended upon. Various species evolved in these open grassland environments and remnants of this diverse ecosystem provide habitat for many rare species as well as a wide range of more common grassland species.

Many factors contribute to the success of native grassland restorations. One such effect is currently being studied by Margaret Murphy, a graduate student at Western Kentucky. Margaret is conducting a study at Bernheim on the effect of mammals on this restoration process. She is examining the affects of grazing, caused by both small mammals and white tailed deer, on the initial success of plant restoration.

For this project mammal enclosures, exclosures and full access plots were created by constructing fences of steel flashing. Prairie voles were stocked or removed from these plots in order to monitor the effects of the mammal population. In addition, the impact of deer was monitored by constructing exclosures of electrical wire to prevent browsing. Margaret is currently concluding her study on the affects of small mammals and we will be updating this site with her findings.

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Nest Invaders
Cowbirds, once native to prairies, have increased dramatically with the expansion of agricultural space. Edges created between the forest and field provide vital feeding habitats for cowbirds and allow them entry to the forest ecosystem. Proximity to the forest allows cowbirds access to other bird’s nests where they lay their eggs, causing these species to raise them as their own. This parasitic behavior is harmful to other native birds in that the cowbird young mature earlier and leave little food for their nest mates.

Blaine Ferrell, professor at Western Kentucky University recently completed a study assessing the number of Brown-headed cowbirds and their potential host species within Bernheim. This study will determine the threat of cowbirds and provide information upon which management plans can be based. Blaine created various lines that ran from either fields or road edges into the forest. Points were selected along each line where birds were identified by either site or sound.

A total of 45 species, consisting of 711 individual birds were identified during the cowbird breeding season. Of these birds, a total of 33 cowbirds were identified, most frequently observed along field (13) and road edges (8). These results suggest that although cowbirds do penetrate the forest, they prefer to take advantage of nests that are close to open areas.

The plots in the interior of the forest were found to contain more cowbirds if they were off of an old field than if they were off of a road edge, suggesting the greater impact of larger areas of disturbance. One positive note can be added in that the relative abundance of host species implies that cowbirds have not drastically impacted the populations of other birds.

The results of this study show a need for further evaluation of open areas to prevent cowbirds from further infiltrating the natural areas of Bernheim. In order to determine the success of management Bernheim plans to continue this study over the next five to ten years through Western Kentucky University.

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Expanding Bernheim's Glades
There exists within Bernheim several small and rare hillside glades. These glades are characterized by their rocky uneven soil that is inhabited by various grasses and forbes. It is believed that these areas were previously maintained through not only their soil type but also the use of fire. Since the restriction of fire in these communities' many fire sensitive trees have invaded these hillside glades. In order to restore these forest openings to their former size and diversity, Bernheim's Natural Areas staff is conducting an ongoing research project with the University of Kentucky's Dr. Chuck Rhoades. Restoration of these areas involves opening the forest canopy adjacent to these glades to allow the light in that is necessary for these glade species to exist. In order to determine the true impact of fire and cutting on the glade communities, various treatment zones were applied within each of the three glades. Treatment zones included cutting, fire or a combination of the two. Currently Dr. Rhoades and Bernheim's Natural Areas staff have completed the initial assessment of the area and have removed various woody species adjacent to the glades. In addition, Bernheim staff just completed their 320-acre forest burn that included two of the three glade communities. Further monitoring of the glades will be completed throughout this year and the next to determine the impact of this management.

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American Chestnut at Bernheim
The unfortunate story of the American Chestnut and the blight that virtually eliminated them is an integral part of Kentucky's forest history. Prior to the introduction of the fungal chestnut blight, Chestnuts were a dominant overstory species in many parts of Kentucky. Elimination of Chestnuts dramatically altered the composition of Kentucky's forests. Chestnut research is currently underway all over the United States in order to save the American Chestnut. Dr. Chuck Rhoades of the University of Kentucky is currently completing one of these studies at Bernheim. Dr. Rhoades is reintroducing pure American Chestnuts to their original forest environment in order to understand the best conditions for reintroduction. The goal of Dr. Rhodes study at Bernheim is to determine the influence of varying light levels and fire on these young Chestnut saplings. The Chestnuts are currently planted in the forest and will be monitored to determine the initial success of their establishment. Although these saplings are not blight resistant, their initial response to the various conditions will help in understanding future restoration methods.

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Fire
Well, you are probably wondering about all the smoke that has been lingering around Bernheim so we thought we would fill you in on what is going on. Bernheim manages both its meadowlands and woodlands with fire conducting several prescribed burns within both the arboretum and the research forest.  These burns not only help eliminate non-native species but also increase the diversity of plant species. If you travel along Harrison Fork Road, you may see Eagle Ridge. This steep hillside was recently converted from a cedar glade into a native grassland. This burn was patchy as expected, but will allow for the restoration of grassland species.  Our largest prescribed burn was 320 acres in an oak-dominated forest. This fire was a great success due to all the hard work done by Bernheim staff. Research is being conducted in conjunction with this burn in order to determine the affects of fire on oak regeneration and diversity of herbaceous plants growing on the forest floor.

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Japanese Grass – Insights into Invasion
Natural communities across the world face an ongoing influx of non-native vegetation brought to the area as a result of human interference. Although many of these species never cause a problem, occasionally a non-native plant is able to rampantly invade an ecosystem where it has no natural predators. This often causes a severe decline in the native vegetation and can even lead to the elimination of all other species in an area. These extreme consequences have made research and experiments concerning non-native/invasive plants a top priority among natural area’s managers - including those at Bernheim.

Forested ecosystems East of the Mississippi are currently being invaded by Microstegium vimineum, also known as Japanese stilt grass. This species is able to disperse its seed rapidly and overwhelm areas such as creek banks, road edges, lowland fields, and bottomland forests. Carolyn Cromer, a student at the University of Wisconsin-Madison, recently completed her Masters thesis on Microstegium using experiments that she completed here at Bernheim and at nearby Kentucky nature preserves. Carolyn focused on the species interaction with light and with other native vegetation to determine the extent of the species, and by doing so gave natural areas managers a clearer focus on where to begin management efforts.

The results of Carolyn’s study showed that extremely low levels of sunlight, such as those correlated with areas below spice-bush and sugar maple trees, had a significantly negative effect on Microstegium’s growth. Although this may seem like good news, Microstegium was shown to compete effectively with native vegetation at all light levels greater than one percent. The species ability to overwhelm native vegetation was found to reach its peak along forest edges, where its cover was at least fifty percent greater than in other habitats. It was therefore concluded that management efforts should begin with these areas where the reduction of Microstegium could have the greatest effect. Carolyn also took on an additional study regarding Microstegium’s impact on native vegetation. The results of this study showed that there was a negative correlation between Microstegium and the number of other plant species. Although it is unknown what causes this, it serves to prove the detrimental effects on our native ecosystems by this non-native species.

These findings allow us to better understand Microstegium’s impact on our native vegetation and exemplify the need for continual management of the species. Our thanks go out to Carolyn for the valuable research she completed here at Bernheim. We wish her luck in her future endeavors and know that she will continue to make us proud. 

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River Cane Propagation for Canebrake Restoration
Under appropriate growing conditions, river cane (Arundinaria gigantea), the only bamboo species native to the United States, can form dense, monotypic stands called canebrakes. Prior to European settlement, canebrakes covered large areas throughout the southeastern U.S. One canebrake in present day Bourbon County, Kentucky was described as "15 miles long and perhaps half as wide". Overgrazing, land clearing, and alteration of fire regimes that favored river cane are thought to have severely diminished canebrake size and frequency. Today, canebrakes are an endangered plant community.

Work is now underway at Bernheim to document the efficacy of different fertilization and soil moisture regimes on improving growth of river cane transplants. It is hoped that these efforts aimed at achieving a better understanding river cane transplantation will aid in the restoration of canebrake communities. In addition, river cane, with its prolific growth and soil holding capabilities, may prove a useful species in stream restoration and riparian buffer plantings where erosion is a concern. 

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Understanding Glade Communities
Interspersed throughout Kentucky’s forests are small grassland communities referred to as glades. These areas, typically less than an acre, often provide habitat for state or federally-threatened plant species. Forest managers often dedicate time and resources to these communities because they are locally rare and present a unique environmental condition that allows unusual species to flourish. Current research conducted here at Bernheim by Rhodes, Miller, and Shea investigates how the unique soil conditions present in these openings effect what plants are present in these glades as well as the extent of their coverage.

By better understanding the factors that allow these glades to exist, forest managers can better maintain these communities and protect rare species. Current research focused on chemical and physical soil properties and nutrient cycling. Samples were taken from within the glade openings, forest edges, and the surrounding forests to determine the unique characteristics of the glades. Soils in the forest openings were mare alkaline, and contained more extractable calcium and less phosphorus than the adjacent forest communities, while magnesium and potassium ion levels remained constant. Glades were also found to have denser soils that contained more silt and less clay than the forest floor. Nutrient cycling was also found to be varied and forests had more available nitrogen and higher rates of production of ammonium. These significant differences in soil variables indicate that expanding the habitat of glades by mechanically clearing the vegetation may not be enough to encourage habitat expansion. Soil characteristics may be the main variables affecting the location and extent of this rare community.

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Lichens of Bernheim
One of the most important aspects of forest management within Bernheim involves determining what species are present within our boarders.  Once we understand more about these species we can adapt our management practices to help promote and enrich native diversity. The most recent species inventory, conducted by Douglas Ladd, involved cataloging the lichens of Bernheim and determining their distribution.

This study was the first inventory of lichens within this region of Kentucky .  It provides a baseline with which we can compare this community to similar regions across the US .  Lichens are unique species in that they are composed of a fusion between a fungus and an alga.  They play a key role nutrient and water cycling, as well as influencing various invertebrates.

Bernheim’s rolling hills provide a range of habitats - from upland ridges to moist bottomlands - that are a perfect home for a wide variety of lichen species.  Lichens grow on things such as rocks, soil, trees, wood, and other lichens.  This provides ample habitat as each tree species, or type of rock provides a unique niche for lichen species.

After weeks of inventorying sites across Bernheim, Douglas Ladd concluded that there are over 200 taxa of lichens present at Bernheim.  Although this may seem like a large number, it is slightly lower than expected for a 14,000 acre contiguous block of forest.  It is likely that the diversity of lichens is slightly depressed due to previous disturbances such as timber removal to fuel iron ore production in addition to salt mining.  It is also predicted that past and present atmospheric conditions could have a negative impact on the lichen population.  Several lichens that would be expected to be present at Bernheim are known for their sensitivity to acid rain, suggesting again that this may play a key role in lichen composition.

Despite this setback, Douglas Ladd found five rare lichen species at Bernheim.  These five species include: Caloplaca chrysodeta, Cladonia dimorphoclada, Graphis insidiosa, Lecidea ahlesii, Pyrenula plittii.  Four of the five lichens are either at the end of their range or are a straggling remnant of their original population. The most exciting find was Pyrenula plittii, which is actually the only known population of this species known to exist anywhere in the world!  The most recent record of its existence dates all the way back to 1910.  Due to the significance of these lichens, managers here at Bernheim are formulating a plan for additional protection of these species and their surrounding ecosystems.

Thanks again to Douglas Ladd for providing us with such a useful inventory of Bernheims lichens!

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