Here we will provide several examples of how biologists use online databases of plant specimen data. We hope these examples will give teachers and students ideas about the kinds of research and educational exercises they might do with our Virtual Herbarium or with other online databases.
These are all "real" examples in the sense that they all were the products of research on plants of the Northeast United States, they all involved the use of herbarium specimens, and the information used in the graphs is available through our online database. All of these graphs were published or used in formal presentations to groups concerned about managing invasive plants, so, although they may seem simple in some ways, each made a contribution to our understanding of where these plants occur, how that is changing over time or why the plants occur where they do.
This first example is from a paper about an aquatic
mud-mat or Glossostigma cleistanthum.
This plant is a native of Australia and New Zealand and started showing
up in the Northeast only in the 1990s. We don't know how aggressive it
is, but it is spreading quickly, and we fear it may become aggressive.
The plant occurs now as far south as Maryland, but when this paper
appeared it was known only from Connecticut, Rhode Island, New Jersey
and Pennsylvania. The paper pointed out that Glossostigma prefers certain lakes
with sandy bottoms and clear, slightly acidic water. Long Island has
many lakes like that. We suspect that migratory waterfowl, which often
eat aquatic plants, are moving the seeds around, and many ducks pass
over and stop in Long Island ponds during migration. This makes Long
Island ponds likely habitat for Glossostigma,
although it has not yet been found there. Because of the likelihood
that this new, potentially invasive plant may occur in the area, The
Nature Conservancy began summertime surveys looking for Glossostigma on Long Island. To
own map of Glossostigma
populations, go to the Virtual
Herbarium, click on "Search the Herbarium database" and conduct a
search for "Glossostigma
cleistanthum." When you get the results, click on "Map these results"
at the top.
The database also allows researchers to study increases or declines in the frequency of plants. One way to do this is to obtain information on the number of populations of a species that exist each year. Map the Glossostigma data as before. On the right, click on "Options." Then click on "Download records." You then can sort the specimen records by year and make a simple plot showing how many populations exist, adding each year's new populations to the number that existed previously. A graph like this can be modified, adding more species, to see which species are spreading most rapidly. Information like this can be useful for conservation officials. They often have to decide how best to use their resources when there's not enough to do everything that needs to be done. We have many invasive aquatic plants in the Northeast, and there is never enough money to control them. A plot like the one at left suggests that, although Glossostigma is increasing, a different invasive aquatic plant, Najas minor, is spreading even more quickly.
Mapping specimen records available from online databases also can
reveal anomalies in the distribution of species. There can be several
causes of these. If a species has a population that is far distant
from all other populations of a species, it might mean that the species
once had a much larger range and now is contracting for some reason.
This map was produced with data from the Virtual Herbarium of Australia
shows populations of two species of Glossostigma
in their native range. One of the plants (the one in blue) has a more
northern distribution, occurring in the warmer parts of Australia,
whereas the other (the one in red)
is limited largely to the more temperate areas along the southern
coast. These species
are very hard to tell apart, and we suspect that the two most northern
red populations have been misidentified; those probably are
the blue plant. It is unlikely, though not impossible, that the red
plant occurs that far north; it is probably too warm there for that
species. Incidentally, it is the plant with the more temperate
distribution (the red plant), Glossostigma
cleistanthum, that is spreading now through the northeast
Herbarium specimens have many other uses. They are used in education to help students learn the traits that distinguish one family from another. Specimens are used by biologists trying to identify a plant they have collected. Specimens also can be used for molecular analyses that reveal how species are related to each other. All of these kinds of research require that biologists inspect the actual specimens, and they cannot be done with an online database. Many kinds of research, though, can be done remotely just as easily as they can be in the herbarium. All of these analyses rely on the increasing number of databases that are making herbarium specimen records available over the internet. We encourage students, teachers and biologists to come up with new ways in which the online data can be used. And let us know.
The links below take you to the G.S. Torrey Herbarium here at UConn
and to other online databases, to the lesson plans developed already to
the databases and to other education resources.