A little more than 100 years ago, G.W. Stevens traveled across Oklahoma collecting plant specimens as the director of the Oklahoma State Botanical Survey. A portion of his first collecting trip brought him through Love and Carter counties, where several of the ranches operated by Noble Research Institute are located, ranches where I’ve spent much of the last nine years involved in various research projects.
Stevens’ field survey was the first major undertaking to identify what plants occurred in Oklahoma. Up until that point and for the next 50 years or so, the study of natural history mostly revolved around two questions: what and where. In other words, finding out what species were present and where they occurred. The only way to answer those questions was to go out and collect specimens which then were dried, mounted and deposited in herbariums, usually at universities. While people could come along and make maps or study the anatomy of all the specimens of a particular species, nothing really exciting happened in those collections.
G.W. Stevens, pictured above, directed the Oklahoma State Botanical Survey with three major explorations in 1913. During his exploration in April 1913, Stevens traveled through Murray, Carter and Love counties collecting botanical samples that were deposited at the University of Oklahoma.
White four o’clock, left, is a specimen held in the University of Oklahoma’s Robert Bebb Herbarium. Photo courtesy of Amy Buthod, collections manager.
As new technologies were developed and improved in the 1980s and ’90s, the attention shifted to looking at how species and groups were related to one another based on DNA and pollen analysis. This was pretty attractive to folks because it all took place under air conditioning and didn’t involve chiggers and ticks. Tissue samples for a study could easily be extracted from preserved herbarium specimens. Natural history studies dropped off dramatically and are continuing to decline.
There are a lot of questions out there today that didn’t exist when G.W. Stevens and other early collectors were stumbling around through the prairies and woods of Oklahoma. Natural history collections and surveys can contribute a great deal to the answers.
From historical collections and newer samples collected in particular habitats, we can begin to develop a concept of ecosystem health. How many native species are present versus non-natives? How closely do the species present today represent those documented for the site in the past? How have environmental changes affected native vegetation? How have land use practices influenced native vegetation? What can be inferred from the current vegetation about historical land use?
If we detect a difference — some species are absent that were present and new species have appeared — we can ask: What about this site has changed? How rapidly are changes taking place? Can we implement management practices to reverse the changes? Rarely do species invade an intact community. There is usually some disturbance that has taken place that sets the stage. Often the culprit is overgrazing, but it also may be something like a lack of fire. For example, eastern redcedar takes advantage of both situations and causes havoc by invading grassland plant communities.
A great deal of information about the status of vertebrate and invertebrate species can be inferred by the status of the plant communities present. In most cases, the plant community is the habitat for those species. If it’s gone, they’re gone.
During field work in the heavily forested Big Thicket in southeast Texas, I occasionally came across single pitcher plants under closed-canopy pine forests. If they’re only supposed to grow in pine savannas, why were they growing in the middle of the forest? Fires had been suppressed for so long that the pines had taken over the original savannas, which were the habitat for the pitcher plants. I was finding relict populations. Collections data can let us know where such habitats once occurred and where they might occur again, if properly managed.
Collecting Provides Insight Into Invasive and Endangered Species When dealing with invasive species, other questions arise. Have those species always been around, or are they introduced? When did they first turn up? If they have always been around, why are they causing problems now? What has changed? How fast is the change occurring? Collections data can help answer those questions as well.
Natural history collections may also provide insight into endangered species that are particular about where they live. Data on specimen labels about geology and soils can be put into a GIS system and analyzed to locate other potential sites where those species might be found or could be reintroduced. It is also possible that what we thought was an endangered species based on museum collections isn’t nearly as endangered once someone starts to focus on collecting them. Many organisms are easy to overlook and just are seldom collected.
How many species occur on a site? Do some appear only during or after really dry periods, or really wet ones? Several native forbs dramatically increase in abundance after fires. It’s not that they are suddenly invading, but it’s how that plant community is responding to fire. After every fire, those species behave in that fashion. Two years after the fire, the forbs will once more be minor components of that community. Some of the species occurring on a site don’t show up every year, or even every decade. Seeds remain viable in the soil for extended periods of time and may germinate only when conditions are just right. This may occur only when the overhead canopy has been removed, such as in the case of a fire or after a severe drought.
Collecting in an area, even over an entire season, still doesn’t capture all of the biodiversity that is likely to be present there. I’m specifically referring to plants here, but I think that trend holds true for whatever group of organisms one might study. Collecting is the only way to answer many biodiversity questions. We use some other technologies such as camera surveys or acoustic surveys to help measure biodiversity with animals, but they don’t work with plants.
Many of our ecosystems provide the food we eat and the water we drink. They also cycle nutrients and sequester carbon. Studying those ecosystems starts with knowing what organisms are present; in other words, collecting and depositing specimens. Mapping and defining these communities requires knowing which species assemblages — all the species in an area — occur in them.
Historically, traditional surveys and collections were the primary method of acquiring this data. Current efforts to classify and map vegetation still depend greatly upon data collected during early surveys as well as new data from ongoing surveys. Collecting field data tells us what is happening now in those communities. Previous collections provide information as to what those communities were originally. Combined with other data on land use patterns or climatology, we can then begin to predict what may happen within those communities in the future and how they may respond to disturbances. We can collect enormous amounts of remotely sensed data with satellites and UAVs, but without some knowledge of the plant communities on the ground, there’s no way to make sense of all the interesting patterns present in that imagery.
What can natural history collections tell us about climate? Plants are usually collected while they have flowers present. The collection date and location are always recorded along with any observations about local habitat, soils or geology. If you have a number of specimens of the same species collected in roughly the same location over a period of years, you can look at when those species flowered and compare past records to present. There can be a lot of variation from one year to the next, so decades of data may be necessary to say much about any trends. There are some maple trees in Red Rock Canyon near Hinton, Oklahoma, that suggest our climate may have been dramatically different in the distant past. Maples don’t generally grow in the Great Plains, except in highly sheltered areas like deep canyons. When there was an ice sheet present in northeast Kansas, though, maples might have been much more widely distributed. Those maples represent a relict population that was established under a much different climate.
The Oklahoma Natural Heritage Inventory (ONHI) in Norman, Oklahoma, is the agency tasked with keeping track of the organisms that occur within the state. As the state’s central repository, the agency maintains several datasets on state organisms, including the Oklahoma Vascular Plant Database. ONHI works with organizations such as the University of Oklahoma’s Bebb Herbarium and the Sam Noble Museum, Oklahoma’s Museum of Natural History, as they contribute to and catalog collections of the organisms of the state.
The Noble Research Institute has been working with ONHI to survey plants from our three research and demonstration ranches in Love County to provide us with information regarding the current level of plant biodiversity on our ranches as well as fill in some gaps in collections for the county. Even though plant survey efforts have not yet been completed, more than 500 species of vascular plants have been recorded just from those three ranches. Of those, we suspect 20-30 species have never been reported from Love County before. We collected one species that may well be the first report for the whole state of Oklahoma.
While many of the techniques involved in the study of natural history have changed very little in the last 400 hundred years, the application of new technologies to the old data and methods has dramatically increased the value of natural history collections and surveys and is likely to continue to do so for a long time.
This is the sort of thing that Aldo Leopold, the father of wildlife conservation, had in mind when he said, “To keep every cog and wheel is the first precaution of intelligent tinkering.”