Natural History Collections for future Ecosystems

Last week a bunch of the natural science curators here at the Illinois State Museum presented a poster at a small conference (downloadable PDF here). Normally, a conference poster isn’t a big deal or all that unique, but this may be a first. The theme of this year’s conference was “Taking stock before the connection” and was concerned with establishing accurate and relevant ecological baselines as goals for conservation activities. This isn’t the sort of conference you would normally see studies of zooarchaeological specimens or deer paleopathology, but this year we decided it was time to illustrate the relevance of ISM natural history collections to modern conservation biology.

We aren’t the first to do this. Different disciplines, typically considered the more “historic” sciences like archaeology and paleontology, have been working on these issues for at least a decade. In paleontology this approach is called “Conservation Paleobiology”, in archaeology it’s called “Applied Paleozoology”. Both approaches are very similar to the backwards looking “historical ecology” that goes hand in hand with restoration ecology.  Practitioners of all these disciplines agree that in order to understand the wide range of variability in modern ecosystems, we need an understanding of processes and patterns that go deeper than the historical record. Let’s face it. The picture of historical ecological patterns we get from early Euro-American explorers or early settlers capture a snapshot in time that is not very representative of the larger picture. By the time these early chroniclers were traipsing across the Midwest and Great Plains, pre-contact ecosystems had already been largely altered or even obliterated. Horses were introduced by the Spanish in the late 1500s and by the 17th century had expanded throughout the western US. By the time fur traders first contacted Native groups in the eastern Great Plains, epidemics of European diseases had already decimated their communities. Before the first settlers built rough cabins in what is today central Illinois, years of warfare and genocide had reduced the human footprint to the point that the vegetation in many parts of the Midwest were released from human utilization and in successional stages.  These are just a few examples of large-scale ecological changes brought about by the changes in the human landscape at contact. This begs the question often asked by planners prior to making decisions, what is the ecological baseline that should be the goal for conservation efforts? In many cases, these planners now recognize that there is no single baseline. No single date that we can point to and say, “this is the natural state”. Modern landscapes can be managed to provide basic ecosystem functions, or as one author puts it, “goods and services”. But what were those goods and services in pre-modern ecosystems? Are there metrics that we can use to document BOTH the modern and pre-modern to gauge which management schemes are appropriate? That was what we set out to do with this presentation. We presented five case studies that illustrate possible ways that paleoecological research on natural history collections (i.e., Paleontology, Archaeology, Botany, Zoology) can offer direct advice and specific answers to modern conservation science.

Case Study #1: Niche Characterization of North American Bison (C. Widga, T. Martin, A. Harn)

During the last 10,000 years, bison were a keystone herbivore in grassland ecosystems. They performed vital functions in nutrient cycling, vegetation succession and predator/prey dynamics. Bison were also present east of the Mississippi River in the eastern forests. The earliest record for bison in Illinois is ~8900 BP and sporadic records persist into the historic period (McMillan, 2006). Notable localities include: Anderson and Markman Peat Mines (Whiteside Co., ~3000-8900 BP), Ottawa Silica Co. (LaSalle Co., 4300 BP), and Lonza-Caterpillar (Peoria Co., 2300 BP)(Figure 3). Unfortunately, most historical documents describing bison date to a time period when ecosystems were rapidly changing. For a variety of reasons (e.g., changing human land-use), the historic record of bison is not analogous to the pre-modern baseline. Indeed, historical documents illustrate bison as seasonally mobile large herds, a picture that is completely incongruous with paleoecological patterns. Sub-fossil bison specimens archive valuable paleoecological information on how bison lived in the Midwest.

In habitats dominated by short or mid-grass prairies, the cusps of bison teeth show flat wear by age 5-6 years. This is due to a high silica (i.e., grasses), high grit diet. However, pre-contact bison from the Midwest show a shearing wear pattern in cheek teeth (Figure 2). This pattern is present in herbivores who are browsers or mixed feeders from closed or partially closed habitats (e.g., deer, elk). Stable isotope data also indicate a diet dominated by C3 plants (i.e., shrubs, trees, sedges), despite the prevalence of tallgrass prairie (C4 dominant) in upland habitats (Widga, 2006).

Although large bison assemblages of 100+ animals are present during the early Holocene in the Great Plains, the smaller sizes of the eastern Plains assemblages are consistent with small-scale, temporary social groups that have been documented in modern conservation herds. The maximum herd size for midwestern bison assemblages is ~20 (Simonsen Site, NW Iowa). Other midwestern assemblages in MN, WI, and IL are smaller than this maximum. Females contributed less to overall herd populations in the archaeological assemblages than in modern herds, suggesting that managed sex ratios in the latter are uncommon in prehistoric bison groups (Figure 4). Although there may be economic and safety reasons for maintaining high numbers of females, these sex ratios should not be considered characteristic of natural variability in pre-contact bison herds. Furthermore, many modern herds maintain large juvenile populations (<4 years old), often approaching or exceeding half of the overall herd size. None of the archaeological assemblages contain more than a handful of juveniles.

Bison in the Midwest were ecologically distinct from their counterparts on the Great Plains. The pre-modern bison niche in Illinois can be characterized as small, local herds browsing shrubs and woody vegetation along river valleys.

Case Study #2: Baseline Expectations for the Distribution of Illinois Carnivores (M. Mahoney, E. Grimm)

 

Mountain lion (Puma concolor), gray wolf (Canis lupus), and American black bear (Ursus americanus) suffered sizeable reductions in distribution over the past 250 years when they were eradicated from much of eastern North America (Whitaker and Hamilton, 1998). All three species were extirpated from Illinois by 1870 (Hoffmeister, 1989). Today, large carnivore populations in many regions are healthy and increasing in size due to a combination of factors including species-specific protections at the state and federal level, protection of habitat, and regulation of hunting.

Two of these three apex predators are occasional migrants into Illinois (Figs. 1 and 2) and the third is likely to appear soon. It is a matter of time before they establish populations in Illinois as they expand from other parts of their ranges. What was the former distribution of these species in Illinois? What habitats are available today? Can we use past distributions to either predict where they might become established or to restore appropriate habitat types?

Historical records provide limited information on the distribution of large carnivores in Illinois as encountered by explorers, trappers, and early settlers and mostly serve to document the last known localities of large carnivores before their extirpation from Illinois in the mid-1800s (Hoffmeister, 1989, Fig. 2). These records have other known weaknesses. For example, mountain lion and bobcat (Lynx rufus) were not reliably distinguished until the early 1800s and wolves and coyotes were often conflated even after wolves were extirpated (Hoffmeister, 1989).

The Neotoma Paleoecology Database is an online resource for fossil and archeological site and sample information. It is a freely searchable compilation of datasets from numerous researchers and institutions. The primary components are fossil mammal (FAUNMAP) and North American pollen (NAPD) including data from sites spanning the last 5 million years. The Neotoma data (Fig. 3) expand our knowledge of the range of apex carnivores in Illinois both geographically and over time.

Bear is reported from over 40 Late Holocene localities (0-3500 BP). Wolf records (N=30) extend further south in Illinois than historical records indicate and some sites date to over 6000 BP. There are fewer mountain lion records (N=12), but they are widespread and occur up to 4000 BP. One intriguing result is the substantial overlap in site occurrences between gray wolf and black bear. Mountain lion co-occurs with bear at a few sites, and not at all with wolf. These data provide information on species’ occurrence over a deeper time span than is possible from historical records. This gives insight into the presence of animals on the landscape prior to and during past ecological changes, both natural and human mediated.

Case Study #3: Resilience of Deer to Traumatic Limb Injuries (T. Martin, D. Lawler)

Investigations of large archaeological faunal assemblages often reveal unique incidences of animal pathology. Although interesting as curiosities, pathological specimens can disclose insights on past animal populations and the human groups that were exploiting these animals. Four specimens from the Fort St. Joseph (20BE23) and Fort Ouiatenon(12T9) sites illustrate incidences of trauma suffered by white-tailed deer (Odocoileus virginianus) at eighteenth-century trading posts that were inhabited by French settlers and their Native American wives and trading partners. Gross examination and application of x-ray radiography and micro-computed tomography shows a pattern of severely broken front legs on individual deer that survived their initial injuries long enough to permit bone healing and remodeling before the deer ultimately became the victims of Native American or French hunters. Specifically, environmental sheltering from predation, food and water availability in immediate surroundings, and fractured bone ends in reasonable apposition could accomplish functional healing through the downward pull of gravity, heavy limb weight, and limited movement. Individual diagnoses can reveal details about the traumatic injury, malnutrition, and/or infections, and the resiliency of the animal in surviving injuries that initially might be considered to be fatal.

Case Study #4: Pre-Modern Fisheries and Aquatic Ecosystems (B. Styles, T. Martin, M. Wiant)

Although wetland ecologists draw on a variety of modern and historical resources to achieve conservation goals, many system-altering events occurred prior to documentation. The Illinois River and its flood plain were dramatically transformed between 1870 and 1930 by the construction of locks and dams, levees, and the Sanitary and Ship Canal. Drawing on a long-term Illinois River valley archaeological research program, zooarchaeologists have acquired a deep-time perspective on changes to terrestrial and aquatic ecosystems.

A total of 59 fish species have been recorded from four Illinois valley archaeological sites. However, only 12 species, Buffalo, Redhorse sucker, Black and Brown bullheads, Channel catfish, Bass, Sunfish, Bowfin, Gar, Freshwater drum, Northern Pike, and Pike spp., were found in every assemblage. Analysis of proportional data based on the Minimum Number of Individuals indicates that a few species dominate the combined assemblage (Figure 1). These include: Black bullhead, Indeterminate catfish, Bowfin, and Gar, each of which accounts for more than 20% of the total number of individuals. All of these species are common in Illinois River floodplain backwater lakes. However, it is difficult to discern whether this particular distribution represents food preference, the exploitation of particular habitats with specific technology, or some combination thereof.

Case Study #5: Freshwater Mussel Fauna in the Illinois River Basin, Compositional Variation and Change (R. Warren)

Malacologists have compiled invaluable lists of freshwater mussel species native to the Illinois River Basin based on museum collections and historical records. However, lists alone tell us little about the compositions and habitat associations of mussel communities before they were transformed by dam construction and other human impacts during the 19th and 20th centuries. This study uses archaeological shell collections to explore compositional variation among native mussel communities in the Illinois Basin, and to develop a proxy baseline for looking at the magnitude of compositional change in modern mussel faunas. The archaeological material includes 49 shell samples from 30 archaeological sites (Figure 1). The samples represent prehistoric and historic Native American mussel collections that were deposited in village or mortuary contexts. They range in age from 200-9500 BP, although most date to the late Holocene (<2000 BP). Fifty species occur in the total sample of 29,407 identified specimens.

In the archaeological samples, species diversity increases downstream in the Illinois Basin. Species composition is highly variable in the basin as a whole. In most samples the leading dominant species is either the threeridge (Amblema plicata) or the spike (Elliptio dilatata), but five other species predominate in at least one sample. A multivariate ordination of abundance data using detrended correspondence analysis (DCA) orders samples and species along two principal axes of variation (Figure 2). Correlations of sample DCA coordinates with independent environmental variables, mussel habitat scores, and proportions of modified shell indicate that compositional variation reflects (1) down-valley geographical differences among mussel communities, (2) local access to an array of aquatic habitats (large river, creeks, and backwater lakes and sloughs), and (3) cultural selection, in a few cases, of certain species as raw material for creating shell artifacts (Figure 3).

Analysis of mussel samples likely gathered from the Illinois River mainstem shows evidence of community variability and habitat associations that are missing in modern mussel faunas. Samples dominated by the spike (E. dilatata) and mucket (Actinonaias ligamentina) are indicative of a shallow large river with coarse substrate, whereas samples dominated by the threeridge (A. plicata) are indicative of a deeper large river with fine substrate. Shoal habitats are indicated not just in the upper Illinois River, which was historically infamous for its dangerous rapids, but also in the central and lower sections of the valley where reaches of deeper water also occurred. A 1960s mussel survey of the river showed a significant decline in species diversity during the 20th century, when about half of the species were extirpated. Baseline data from the archaeological model indicate there was also a narrowing of mussel community variability and a constriction of habitat associations. These changes may be related to historical human impacts on the stream including pollution, sedimentation, and dam construction.

Suggested Reading

Dietl, G. P., & Flessa, K. W. (2011). Conservation paleobiology: putting the dead to work. Trends in Ecology & Evolution26(1), 30-37.

Hoffmeister, D. F. (1989). Mammals of Illinois. Urbana: University of Illinois Press.

Jackson, S. T., & Hobbs, R. J. (2009). Ecological restoration in the light of ecological history. Science325(5940), 567.

McMillan, R. B. (2006). Perspectives on the biogeography and archaeology of bison in Illinois. In: Records of Early Bison in Illinois, R. B. McMillan, editor, pp. 67-147. Illinois State Museum Scientific Papers 31. Springfield.

Whitaker, J. O., & Hamilton, W. J. (1998). Mammals of the eastern United States. Cornell University Press.

Widga, C. (2006). Niche variability in late Holocene bison: a perspective from Big Bone Lick, KY. Journal of archaeological science33(9), 1237-1255.

Wolverton, S., & Lyman, R. L. (Eds.). (2012). Conservation biology and applied zooarchaeology. University of Arizona Press.

Midwestern Mammoths and Mastodonts: The M-cubed project

BOB is a gigantic, flying pig that inhabits the downtown of Grand Rapids, MI. Need I say more?

Evidently elephants aren’t the only megafauna in town. BOB is a gigantic, flying pig inhabiting the downtown of Grand Rapids, MI, not far from the GR Public Museum where we were looking at Mammoths and Mastodonts. Need I say more?

Note: This is the first post in a series focused on a 4-year, National Science Foundation funded project to look at the extinction of Mammoths and Mastodonts in the Midwest. 

For the last few years we’ve been traveling…a lot. We started a project in 2011 to better understand 1) when mammoths and mastodonts went extinct, and 2) the ecological mechanisms that might have played a major role in how they went extinct. The major foundation of this project is a museum-by-museum survey of mammoths and mastodonts in collections from nine states and one province (MN, WI, IA, MO, IL, IN, OH, KY, MI, and ON).  Over the last 2.5 years, we’ve documented mammoths and mastodonts from 576 localities.

Museums and Research Collections visited by the M-cubed project as of January 2014.

Museums and Research Collections visited by the M-cubed project as of January 2014.

When we started this project, we knew that the Midwest was a hotbed for Pleistocene proboscideans. A compilation of known/published localities showed a continent-wide distribution, but definitely a concentration in the Great Lakes. Of course, as with most things paleontological, the best represented individuals are the youngest, and both genera overlap with the first humans in to the New World. The last standing mammoths on the continent are widely separated in space, found from the South Dakota Badlands to upstate New York. After the last-glacial maximum, mastodonts seem to be limited to forested areas of the Great Lakes region and Northwestern North America.

Map of Midwestern Proboscidean localities. Red=Mastodont; Blue=Mammoth; Black=Unknown proboscidean

Map of Midwestern Proboscidean localities vouchered in regional museums. Red=Mastodont; Blue=Mammoth; Black=Unknown proboscidean

Mammoth and mastodont studies lie at the intersection of major research questions in a number of different disciplines. The reason that they are so important is primarily due to the fact that they are so common and widespread in the fossil record. Why, you ask? Probably size and distribution. Their remains are big enough to be seen from the cab of a tractor or backhoe, and were distributed coast to coast during the last half of the Pleistocene. Since they are relatively widespread and common components of the fossil record, we can get an elephant’s eye view of ecological changes, IF we know what questions to ask. Their remains are also much more common in museum collections than other victims of the terminal Pleistocene extinction event, so they might give us a glimpse into HOW the extinction occurred. 

Why (Part I): Preposterous Proboscidean Paradigm Shifts

The 2005 discovery of a mammoth tusk in the bed of Sugar Creek (central Illinois) started it all. Dennis Campbell, biology professor at Lincoln College (and ISM research associate), had brought a class out to the creek to census freshwater mussels when Judd McCullum, (then a student in the class), stumbled across a large cylindrical object. Despite good-natured ribbing that it was “just a tree trunk”, Judd was convinced it was a mammoth tusk…and he was right. ISM paleontologist Jeff Saunders identified the tusk as a woolly mammoth. Conventional thinking had woolly mammoths in Illinois at the same time as the glaciers. We thought that they occupied the narrow band of tundra in front of the massive continent-grinding glaciers that covered the Midwest up until ~18,000 years ago.

Upper right jaw of Mammuthus primigenius from Lincoln College Creekside Center for Outdoor Environmental Education, Sugar Creek, Logan County, IL.

Upper right jaw of Mammuthus primigenius from Lincoln College Creekside Center for Outdoor Environmental Education, Sugar Creek, Logan County, IL.

To be thorough, Jeff submitted a sample for radiocarbon dating anyway. The results were surprising. Rather than dating to the time of the glaciers, the Lincoln College mammoth dated a few thousand years later, when central Illinois was covered by a cold swamp, with black ash and spruce as the dominant vegetation, not a grassland. This was a game-changer. Not only were woolly mammoths found outside of their traditional tundra habitat, but when the glaciers left the area, they stayed and survived in changing Midwestern ecosystems until their extinction, ~12,000 years ago.

Meanwhile, a graduate student at the University of Utah developed an interest in the ancient DNA of North American mammoths. Jake Enk, now finishing his PhD at MacMaster University in Ontario, managed to extract a good chunk of mitochondrial DNA from the Huntington Mammoth in Utah. The Huntington mammoth is the epitome of a Columbian Mammoth. It’s from the heart of the Columbian mammoth range, Utah. It’s cheek teeth, although fairly worn (this animal was 55-60 years old), consist of 7+ enamel ridge-plates spread out into a relatively long tooth (~6 plates per 10 cm). For good measure, Enk also extracted DNA from two additional Columbian mammoth teeth from Wyoming. Surprisingly, when compared to woolly mammoth DNA from Alaska and Siberia, these Columbian mammoths were similar. Actually, they were VERY similar. The three Columbian mammoth mtDNA sequences nested nicely within one of the Alaskan woolly clades. The take home message was that morphological variability in mammoths is much greater than genetic differences. These were not separate species–they probably don’t even merit being a sub-species.

Overmyer Mastodont on exhibit at the Cincinnati Museum Center. Pictured with ISM curator Jeff Saunders.

Overmyer Mastodont on exhibit at the Cincinnati Museum Center. Pictured with ISM curator Jeff Saunders.

But mastodonts were not immune to paradigm shifts. In 2011, Neal Woodman and Nancy Beaven published a report on the dating of a mastodon in northern Indiana, the Overmyer mastodon. The date they reported was 1500 years younger than expected. The typical pattern was that mastodonts went extinct ~12,900 BP, only a few hundred years after the first major human cultural group (Clovis) appears on the scene. The Overmyer animal, if the dates were to be believed, meant that mastodons survived not only the first wave of human colonization, but lived side-by-side with human groups almost into the Holocene! 

Studies like these got us to thinking. What if there are other assumptions about the habitat preferences and behaviors of mammoths and mastodonts that we are wrong about? What would happen if we dated more specimens–or used new techniques for insight into paleodiets and behavior (i.e., stable isotopes) or population dynamics (i.e., ancient DNA)? Was the Lincoln College Mammoth the exception? Or the rule? What do the major morphological differences between different mammoth populations mean if they don’t reflect relatedness–or evolutionary history? Did Mastodonts really hang on so late? Why was there such a large gap between the Overmyer mastodont and other dated animals in the Midwest? All of a sudden, there were a lot of questions that we didn’t know the answer to. 

Who common was this scene? Did Paleoindians really hunt and butcher mammoths? Diorama at the Kenosha Public Museum, WI.

How common was this scene? Did Paleoindians really hunt and butcher mammoths? Diorama at the Kenosha Public Museum, WI.

Why (Part II): Elaborate Extinction Scenarios needing Evaluation!

These questions are important not only for understanding past ecological conditions, but for understanding one of those BIG questions…why did 35 genera of North American megafauna (species >100 kg) go extinct at the end of the last Ice Age? This extinction event is considered one of the BIG 5 mass extinctions in the history of life on Earth. Yet it is unique from earlier mass extinctions. In addition to being the most recent, the majority of the victims were the largest of the large fauna. Small fauna were spared, more or less, or managed to migrate to new ranges. Furthermore, the extinction of these species coincided with major climate changes AND the introduction of a novel, supposedly predatory species known to profoundly alter its environment and potentially overhunt its prey, Homo sapiens.  The discussion surrounding this extinction event in recent years has become increasingly polarized. There are a number of scenarios that have been proposed to explain this extinction. Perhaps some of the megafauna were killed off by colonizing human populations, with the rest doomed as the result of ecosystem reorganization after the loss of keystone species such as mammoths. Alternatively, abrupt climate changes may have stressed megafaunal populations to the breaking point. Deglaciation was not simply a gradual warming. The glacial spring came in stops and starts, and may have presented megafaunal populations with a moving target. Never quite able to adjust to changing conditions. These are the main working hypotheses, but of course, there are others. Was it the mid-air explosion of a comet over glacial ice in Canada? A hypervirulent disease? A combination of the above? It is hard to say without more hard data on the timing and ecology of key extinct species such as mammoths and mastodonts. Beware of TV documentaries claiming that we now know the answer to what caused these extinctions. Most scientists agree (although there a vocal few who don’t) that we don’t have enough data to tease out the smoking gun…let alone identify who or what pulled the trigger!

A) Schematic view of custom-built micromill for collecting <1 mg samples of tooth enamel for stable isotope analyses. B) Sampling schema for a block of enamel encompassing 1 cm of tooth growth (~1 year). C) Image of sample collection (note: rotated 90 deg. from B)

How (Part I): New Techniques

But how do you tackle something as big as megafaunal extinctions? This is a global pattern involving many different species and ecosystems. What sort of data do you need to distinguish between different extinction scenarios? Obviously, timing is everything. In the last decade or so, direct dating of megafaunal bones has become more accurate and commonplace. For this project, we’ve been dating a lot fossils from museums, trying to fill in the gaps in space and time. We hope to say something about when these animals ultimately went extinct using new and improved chronological datasets. We also believe that animal ecology is an important aspect of survival, so we are utilizing techniques that capture the details of individual life histories. Specifically, chemical signatures from bones and teeth (in the form of stable isotopes) that can tell us about animal diets and mobility. (more on what we are learning from these techniques in future posts)

How (Part II): The Team

Modern paleontology does not happen without a team of experts, each providing critical data for hypothesis testing. This project is a collaboration between many different experts. Jeff Saunders (ISM) and myself are vertebrate paleontologists/paleoecologists who are tasked with understanding biogeographic variation in space. Stacey Lengyel (ISM) is an expert in dating techniques–she also happens to be creating a great website on Ice Ace mammals that will be launched this spring. Greg Hodgins is a bone chemist and dating expert at the University of Arizona. J. Douglas Walker (University of Kansas) and Alan Walker (Iowa State University) are experts is different types of isotopic analyses. Others have also contributed to our understanding of proboscidean paleoecology. Veterinarian Dennis Lawler (ISM) has been instrumental in exploring the impact of disease on mammoths and mastodonts and Eric Grimm (ISM) has provided environmental context for dated specimens through his work on ancient pollen recovered from the mud of midwestern lakes.

Looking ahead.

As we scale back the data acquisition phase of this project and focus more on analyzing the datasets that we’ve collected, we’ll have more to say about how mammoths and mastodonts lived and died, at least across the Midwest. A significant component of this project is dedicated to communicating our results to the public, primarily through online resources like this blog and the aforementioned website. So stay tuned for future developments. The data have started rolling in.

Additional Reading

Enk, J., Devault, A., Debruyne, R., King, C. E., Treangen, T., O’Rourke, D., … & Poinar, H. (2011). Complete Columbian mammoth mitogenome suggests interbreeding with woolly mammoths. Genome biology12(5), R51.

Saunders, J. J., Grimm, E. C., Widga, C. C., Campbell, G. D., Curry, B. B., Grimley, D. A., … & Treworgy, J. D. (2010). Paradigms and proboscideans in the southern Great Lakes region, USA. Quaternary International217(1), 175-187.

Woodman, N., & Beavan Athfield, N. (2009). Post-Clovis survival of American mastodon in the southern Great Lakes region of North America. Quaternary Research72(3), 359-363.

Bats in the Attic

Eptesicus fuscus, collected by Paul Parmalee, 8 miles south of Galena, IL. 1953.

A few nights ago, just as I was stumbling to bed, I heard something. It was a distinct fluttering sound–occasionally accented by a light thump. It was something I was able to place, all too well. A bat flying around our bedroom. Resigned to late-night adrenaline, I found an old blanket, wrapped the critter up, and released it in the backyard. Truth be told, it probably found its way back into my attic faster than I made it back to bed.

A little backstory is appropriate. We live in an old house in the central part of Springfield, IL. Lots of trees on the street. Lots of cracks in the old wood siding. Try as I might, I can’t seem to seal all of those cracks (probably has something to do with my ladder that doesn’t go all the way to the top floor, no jokes please). So. Much to my ongoing frustration. We get the occasional bat (or 3) in our attic. When it gets cold, they like to slip under the attic door and visit the warmer parts of the house. The thermometer read -17 F for at least two days last week…so it’s been cold.

That said, a bat flying around our house in January surprised us. Bats are supposed to hibernate, right? A little judicious googling, and I found that this particular species, Big Brown Bat (Eptesicus fuscus), is no stranger to winter, and will occasionally move its winter roost, or fly around looking for something to drink on warmer days. No one told it that the Casa de Widga was closed for the season. Bats are interesting little critters. They’ve been around since the early Eocene (~52 million years ago). Even at that time they had already developed the capacity for winged flight–so they broke off from the more generalist mammal family tree even earlier. The species Eptesicus fuscus, like my midnight friend, has been in the Midwest since the Ice Age, the fossil record gets squirrely beyond that.

Entrance to Bat Cave, Mammoth Cave National Park, KY.

Entrance to Bat Cave, Mammoth Cave National Park, KY. Photo by Rickard Toomey, III

It’s probably appropriate that this little fellow came to visit me since we’ve been thinking a lot about bats lately. In 1999, ISM researchers Mona Colburn and Rick Toomey (now at Mammoth Cave National Park) visited a cave in Kentucky, only a few miles away from the main entrance to the world renowned Mammoth Cave. About 300 yards back into this cave, the trail cuts through a bank of sediment where to the naked eye–it looks like someone scattered a few boxes of toothpicks on the ground. Ok. So a LOT of toothpicks. Within these sediments are a series of bonebeds where thousands, perhaps hundreds of thousands, of bats are deposited. It probably wasn’t a single event that did them all in. In fact, there are at least 11 different layers, each representing a different accumulation/concentration episode. Rick and Mona carefully excavated samples from each of the layers, brought them back to the ISM, screened away the sediment, and started trying to identify who’s who. This is easier said than done. The bat genus Myotis is very species rich (>100 species). Most of these species overlap significantly in size, show somewhat similar behavioral/roosting patterns, and most of the skeleton is morphologically indistinguishable between species. Those markers that distinguish living species of bats such as coat color or length, don’t help us much with fossil material. So out of >3000 bones recorded from the few gallons of sediment from bat cave, 7 species were identified (only 127 bones, <5% of the total). The rest were taxonomically ambiguous. Despite this, the sample is important to modern conservation decisions in the cave. In the early part of the 20th century, bat cave was blasted shut, and in 1937, flooded by the nearby Green River. Did the blasting and flooding have something to do with the mass bat deaths?

Bat bones from Level 4, Bat Cave, KY

Bat bones from Level 4, Bat Cave, KY. Photo by Mona Colburn.

In 2008 we sent a few of these bones out for radiocarbon dating, with some surprising results. The uppermost bonebed dated to the late Holocene, ~2200 years ago, while the bottom layer dated to ~10,800 years ago. One of the middle bonebeds had an intermediate age ~4000 BP. Obviously, these bones were deposited too early to be the result of modern events. But how did they get there? Why are the so many of them? This is where taphonomy–the study of what happens to things after they’ve died–comes in. Are the long bones all oriented in the same direction by water flow? Do they show polishing or etching by stomach acids from a carnivore? Answers to these questions will point us in the right direction.

Unfortunately, we’re a little in uncharted territory here. Most of the techniques we use to understand bonebeds were developed in sites with large fauna (e.g., dinosaurs, bison, etc.), not microfauna. Do the same methods apply? How do you record orientation when the slightest nudge of the brush moves the tiny little bone you are trying to excavate? New technology may help. A few years ago, Russ Graham took a core with a large-diameter PVC pipe from a cave deposit in the Black Hills. He capped the ends, and once he returned to Penn State University, had it CT scanned. The scan showed tiny fragmented rodent skulls that would not have survived excavation. It preserved articulated elements and their orientations in situ. Perhaps this is the way to analyze the taphonomy of microfaunal bonebeds? That’s the next step in our bat cave work. I’ll let you know how it turns out.

Fossils in the round: 3D scanning and printing

Dunlap Canis dirus

This 3D model was rendered from a CT scan. The original specimen was recovered by W.D. Frankforter in 1959 near Dunlap, IA and is in the collection of the Sanford Museum and Planetarium, Cherokee, IA.

Note: It is January 2014 and this blog has been sitting stagnant for quite awhile. Over the next few months, I have a number of posts planned. Most are about the paleontology/paleoecology of Ice Age mammals, but I’m planning a few that will focus on methods and documentation–especially for the amateur community. So stay tuned!

A few weeks ago, this article appeared in the Springfield Journal Register. I thought it was a very good article–evidently my head even made it “above the fold” on the front page (which I’m told is a good thing). I’m always surprised at the “big deal” factor of 3D. Yes, some of it may be because the technology is coming down in price, and the free and open source (FOSS) software resources are out there–and very good. But part of me hopes that it is something bigger, a profound change in the way we think about museum objects and who has access to them.

For my part, thinking in 3D is simply an extension of what we’ve always done. Bone morphology (size and shape) is the bread and butter of most paleontologists. We are always trying to tease out the reasons why a bone is this species rather than that species, and 99% of the time, the answer hinges on its shape. The new 3D technologies are making this easier. So we’ve been scanning specimens from our collections–almost constantly–for the last few months. Everything from Dire Wolves, to Tully Monsters, Mastodon feet to trilobites. At this stage, we’re still in the “let’s see how this works” phase, but soon, perhaps very soon, we’re hoping to put many of these 3D models on the web. We’re in good company here. The Smithsonian released a number of 3D scans that can be found here, including a very nice woolly mammoth (it is 3D printer ready!). We’re almost there.

But why would a person want to 3D print a mastodon foot? How might scanned museum specimens be useful to, well, everybody else? Museums have been in the replicating business for a long time. We mold and cast our most significant specimens so they can be shared with researchers and other museums. However, this “analog” way to replicate fossils was sometimes imprecise, and definitely required quite a bit of skilled time and labor. For a number of years, we made mastodons and ground sloths to order. They weren’t cheap, and they were never a money-making proposition. But they provided a valuable service to museums that were not as rich in collections as we are.

Fast forward to the 21st century. Awhile back we reported a very interesting saber-toothed cat find in southeastern Minnesota Cave (see a great blog post on it here). The Minnesota Karst Conservancy, who owns the cave (and therefore the fossils) preferred that the fossils stay in the state. So after our analysis is complete, they will be returned to the Science Museum of Minnesota where an exhibit awaits. Because we spent a lot of time analyzing these materials, I wanted to retain casts here at the Illinois State Museum. In the future, when researchers visit to look at other similar specimens, they can at least capture basic measurements on fossils from this locality. When it came time to discussing making casts of the major bones, it soon became clear that a traditional mold/cast would sacrifice detail and be very labor intensive. Being the sort of person who likes to avoid hard work for the sake of work, I started dreaming up alternatives. Ultimately, we scanned most of the major bones in a CT scanner at a local hospital. The resulting images could be rendered as a 3D model and printed on a 3D printer at MAD Systems in CA (here).

Left: 3D print of Homotherium skull from Tyson Spring Cave, MN. Right, original.

Left: 3D print of Homotherium skull from Tyson Spring Cave, MN. Right, original.

But that’s not the only reason to 3D print things. A physical object can be manipulated and examined in ways that photos cannot. Our current scanning efforts have focused on the most significant fossils in our collections, including: some of North America’s earliest dogs (Koster Site, Greene Co., IL) and the continent’s largest Mastodont (from Boney Spring, MO). It is our job to see that the public benefit and learn from our collections. That they don’t sit on a shelf, forgotten. The more people that can enjoy these objects for themselves, the better!

Where are we going with this technology? We’re not entirely sure yet. Certainly, we will integrate this into ongoing efforts to digitize our collections. We will work 3D models into our outreach and education activities. Will there be more? Undoubtedly. Stay tuned to our FB page and the Think3D website for new developments!

Midwestern Mastodon Bonebeds: Death Traps and Salt Licks

Big mastodon sites have been getting a lot of press lately. In particular, the Snowmass site high up in the Colorado Rockies has produced over 30 mastodons over the course of two field seasons. This site–making national news on a regular basis over the last year–was a pond where the bones of mastodons, mammoths, bison, and ground sloths (to name a few) were found by the dozens. The Snowmastodon site (as it has been called) was featured on Nova a few weeks ago. Kirk Johnson (Denver Museum of Nature and Science) and Dan Fisher (University of Michigan) suggest that the high number of mastodon bones in debris flows are the result animals trapped on the sandy shores of the pond during earthquake liquefaction, and that humans may be partly responsible for a partially articulated mammoth in the upper levels. This is a fascinating site, and we’re looking forward to seeing what comes from the scientific investigations…which have only begun.

However, the Snowmastodon site puts in my mind a few other big mastodon bonebeds. The Boney Spring site in the western Ozarks was excavated by crews from the Universities of Arizona and Missouri, and the Illinois State Museum in the 1970s. The Ozark project explored a number of important paleontological and archaeological localities. Boney Spring itself was the latest of three major paleontological sites spanning the last ~150,000 years. In all, 31 mastodons were excavated from a single component of the site, dating to ~16,000 years ago. This assemblage includes animals of all ages and sexes, including a very large bull, who remains the largest North American mastodon on record. Although dominated by mastodons, the Boney Spring assemblage includes a minor number of other critters, including: 4 Paramylodon harlani (Ground Sloth), 2 giant beavers (Castoroides), horse, and tapir.  Although small mammals are well represented, no large carnivores were present in the assemblage. Long-time ISM curator Jeff Saunders suggested that this concentration of mastodons was the result of environmental conditions–specifically, a severe drought which caused dying mastodons to congregate around the only source of permanent water, Boney Spring.

Another big Midwestern mastodon site is the “Birthplace of American Vertebrate Paleontology” itself, Big Bone Lick, Kentucky. Located in north-central Kentucky near the Ohio River, BBL has been the site of paleontological investigations since the 1730s. By the early 19th century, Thomas Jefferson became interested in the locality, tasking William Clark (of Lewis and Clark fame) to collect fossils for him. Mastodons figured prominently in early collections from BBL. The locality was investigated periodically throughout the 19th century by paleontological notables, but became a research backwater by the early 1900s. In 1962, University of Nebraska paleontologist C. Bertrand Schultz returned to BBL for five field seasons, the first modern paleontological excavations to occur at the site. Schultz and his collaborators discovered that the BBL locality had a complex geological history. Mastodons and other Pleistocene fauna were recovered cheek-to-jowl with bison. But these bison were not the large-horned animals contemporaneous with Pleistocene megafauna, but rather short-horned late Holocene forms. Today, the locality is a state park with an on-site visitor center and full-sized Pleistocene dioramas.  Bones still erode out of the creek banks…

Welcome!

Welcome to my world! This is a research blog about what we do every day at the Illinois State Museum. I am a vertebrate paleontologist who specializes in Ice Age mammals. My research, and much of our museum outreach focuses on the rich record of Quaternary vertebrates in the Midwest and Great Lakes area. Why do we need another blog about giant extinct animals you ask? Doesn’t Switek already take care of that? Believe it or not, modern paleontology is a field whose breadth is huge! Here at the Illinois State Museum, many of the natural history curators are part of the Landscape History program. This describes what we do fairly well. The botanists look at vegetation change and the immediate impact of climate changes on the landscape. Paleontologists and zoologists work with ancient and modern critters, respectively. Archaeologists and historians look at how people used the landscape. Most importantly, we all work together to piece together how past ecosystems work. Just like we can’t understand the dynamics of human populations without understanding their physical environment, it is increasingly evident that we can’t understand vegetation or faunal communities in isolation either.

But why a blog? And why “Backyard Paleo?” Well, I work at the Illinois State Museum. That means that my research and activities are geographically focused on the Midwest. I don’t head west every summer to dig dinosaurs. I don’t travel to Africa to look for human ancestors. It is my job to explore the nooks and crannies of midwestern creekbanks, road-cuts, gravel quarries, and yes, backyards. In reality, there is really cool paleo almost anywhere–you just need to slow down and look closely. This blog allows me to show you (oh loyal reader) what we do, and why it’s important.

At least for the next few months I’ll probably be blogging about Quaternary mammals–with a particular affinity for mammoths and mastodons. This is because we’re in the middle of a big project to understand how and why these massive creatures went extinct at the end of the Ice Age, and frankly, there are a lot of stories to tell about elephants. So stay tuned, and maybe you’ll learn something about YOUR backyard.

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