Curly-cup Gumweed (Grindelia squarrosa), photo by Brian Klinkenberg
Insights into Plant Distributions
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mapping is an excellent educational tool that provides interesting botanical insights. In E-Flora BC, animated maps of plant distributions can
provide a dynamic way of learning about how newly arrived species spread in a region. There are many factors that propel plant dispersal, including climatic factors, predators, disturbance and related niche availability. The speed of dispersal is tied to these, and animated mapping allows us to see when "explosions" of species occurred.
The E-Flora animated maps are based on vascular plant collection records from major herbaria (UBC, RBCM, CAN) for each species from as early as 1881, as well as on data from the provincial BEC database (both collection and observation based). The maps are presently set to display distribution dots in 10 or 25 year increments, but this will eventually be adjusted to smaller increments, allowing more precise insight into arrival and disperal dates that can be correlated with, for example, climatic patterns.
For invasive or alien species, animated mapping of plant collections allows you to
determine when a species was first officially documented (when it was first collected by botanists), and how quickly it dispersed through the province. If we look at the map for giant cow-parsnip/giant hogweed (Heracleum mantegazzianum), for example, we can see that it was documented in the province between 1971 and 1980. Purple loosestrife (Lythrum salicaria) was documented between 1951 and 1960, while ornamental jewelweed was reported between 1926 and 1950. For Kentucky bluegrass (Poa pratensis), however, we can see that this species was documented in the province between 1817 and 1900.
The final map in the animation for a species shows current spread of the species in the province, but this is based only on plant collections. With weedy or common species, once they were documented in the province, few collections were made by botanists. Actual distribution for these species is better represented by observation data. We will incorporate observation data when available, and fill in the distribution maps.
Native Species Mapping
For native species, distribution
maps generally show us where and when botanical exploration has occurred in the province. One interesting insight
provided by distribution mapping of BC species in general is the correlation between distribution
information and roadways and other access routes such as rivers and streams.
This coincidence of collections and access routes is indicative
of one of the challenges of botanical studies in BC: the difficulties
of terrain and accessibility. In British Columbia, terrain and
accessibility influences where we collect, and, ultimately, our
perceptions of species distributions in the province. It is no
accident that the distribution patterns of many BC species coincide
with roadways. One notable example of this comes from a study
of occurrences of tall bugbane (Actaea elata) in British
Columbia (Klinkenberg 2004). Current mapping shows that all known populations
of this endangered species occur within 500 m of a road.
Animated mapping of native species can provide some insight into invasive species distributions. If patterns of collections for native species are similar to patterns for invasive species, then this may indicate that invasive species distributions are more a reflection of collector activity than any actual change in climatic or others factors that drive species distributions.
Some limitations of our animated mapping
A significant limitation of our distribution maps is the accuracy of the databases used. There are several sources of error inherent in databases that include typographical errors, incorrect or reversed UTMs, mix ups in species names and associated data, and incorrently identified specimens. The source of error means that we cannot truly interpret the animated maps as some distribution dots may be incorrectly placed or attributed to the wrong species. In time, as collections databases are edited and specimens checked, this sort of error will be reduced in occurrence.
Accessing our maps
In the table below, click on the icon
to view the animated map [a flash presentation]; click on the icon
to view the Atlas page for that species. Click on a column
heading to sort the table.
Note that a plant species will often have more than one English common name. Some alternate names are listed on the atlas page for the species.
By right-mouse clicking on the map you can stop the
animation (unclick Play),
print the map, or restart the animation (click Play).
|E-Flora BC Animated Maps