Methods

Project Development and Methods of Research

How species were chosen

A list of thirty-four plant species was originally compiled for examination.  These species fell into one of three general categories: 1) Commonly known invasive species that occur in the state of Massachusetts (ex. Centaurea maculosa), 2) Extremely common non-native plant species that were probably introduced around colonial times (ex. Ambrosia artemesifolia), and 3) Plant species native to North America but not to Massachusetts which may or may not have already been recorded as present in this state (ex. Mirabilis nyctaginea).  Species in category 1 were chosen to examine the life history of plants currently causing problems for land managers and conservationists in New England.  Those in category 2 were chosen as a way to measure the completeness of each of the published flora that were used in this study, and thus were not included in the results portion of this project.  Species in category 3 were chosen based on previously published floras that showed these species as existing close to but not within Massachusetts, in the interest of discovering that one or more of these species had expanded their range over an observable time period.

After an initial period of research, the list of species was revised down to thirty-one.  Of these thirty-one, twenty-one species were from categories 1 and 3.  Several species were removed from the list due to lack of clarity concerning their Latin names, and others were removed because there were no recorded occurrences in Massachusetts.  The list presented on this web site, consisting of fourteen species, will be added to as the information is compiled.

Sources

The main sources of information for this project were published flora for the towns and counties of the state of Massachusetts.  The journal Rhodora was also found to be a good source of information due to the inclusion of many floras as well as brief articles describing individual occurrences of species.  The remainder of information was collected from newspaper and journal articles as well as several Master's Theses.  A complete list of References can be found on this web site.

Animated .gif files

The animated images are a graphical way of displaying the information that was gathered through hours of research.  The data was compiled for each species and placed in order according to the date a species was found in a particular town, city or county in Massachusetts.  The data represented on the map is the first Published record of a species in each county.  It is possible that earlier records exist that were not found over the duration of the primary research phase of this project.  Maps will be updated as research continues.  Anyone with information regarding records of any of the fourteen species is encouraged to send email to Jennifer with this information.

If the record was specific to a town or city, that town or city is filled in with a darker shade of the color that the entire county is colored with.  The occurrence of a species in a town or county is considered to be an occurrence in that town's county.  An exception was made for the case of Dukes County, which consists of the islands of Martha's Vineyard as well as the Elizabeth Islands, which were treated as separate entities for this project.

The animation was done by first creating a frame for each occurrence of a species.  Then the frames were meshed together using the animation software Animagic GIF, published by Right to Left Software.  The animation of each map can easily be repeated by reloading the page.


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