|
 My dissertation research
is a critical investigation of the effects of
Melilotus
invasion, to test its ability as a spatial and resource competitor
in native
montane grassland communities
within
Rocky Mountain National Park. I supervised eight field assistants
and several Park research employees to collect extensive species composition
data and soil samples, perform soil analyses, and collect and press plant
specimens. My research also employed burning and nutrient manipulations
to test potential invasion control methods. Exotic invasion, often
fostered by anthropogenic disturbances, can be detrimental to the biodiversity
of indigenous plant communities. This research contributes toward
our understanding of invasion impacts in native montane grassland communities,
the extent that disturbed soil inhibits invasion spread, and implications
for future invaders.
Major funding came from a
National Science Foundation Doctoral Dissertation Improvement Award, the
National Park Service, and the Rocky Mountain Nature Association. Also from the
Colorado Mountain Club, Colorado Natural History, and the University of
Colorado Graduate Department and Museum.
Here's a couple websites that gives more info on
weeds,
exotic invasion and
native communities.
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Yellow Sweet Clover (Melilotus officinalis) |
Melilotus officinalis and M. alba can be found in disturbed areas, commonly
along roadsides. |
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However, it can also be found climbing up
hillsides, or in meadows, |
.... or in areas away from disturbed areas,
such as this riparian area. |
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Yellow sweet clover have several traits that
allow them to be competitive. M. officinalis and M. alba fix
nitrogen from bacteria that form nodules on their roots. |
These biennial species form extensive root
systems in their first year. |
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Rocky Mountain National Park has a high
degree of biodiversity in their montane grasslands! |
 |
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Bouteloua gracilis (Blue Grama) - the eyelash grass! Notice the
yellow sweetclover peaking in the southeast corner. |
Oenothera
(Primrose) - a common weedy species |
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Pentaphylloides floribunda
(Shrubby Cinquefoil) - reponds well to fire |
Epilobium angustifolium
(Fireweed) - a pioneer species that thrives in disturbed areas |
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Penstemon
- lots of varieties found here |
Castilleja miniata (Indian
Paintbrush) - late bloomers, found in open understory of Ponderosa forest
and meadows |
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Antennaria (Pussytoes) -
beautiful ground cover, abundant in these montane communities |
The Rocky Mountain National Park fire crew
helped conduct a prescribed burn treatment on several of my sites. |
|
We used a propane torch - newly obtained and
first time use! I found it was a successful few days - we recorded the
soil temperature at various depths during the fire as well as immediately
before and after.
I'm finding interesting plant recovery. |
Soils were taken immediate after the fire,
four days following and every month thereafter throughout the growing
season. Soil analysis was carefully performed in labs at CU and RMNP |
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In order to test nitrogen saturation
limitations, we added ammonium nitrate to other plots at three times
through the summer. The treatments did affect the sweetclover, both in
nodulation and growth. |
Here's most of us: from left, Brenton
Wonders, Conner Bailey, Emily Friend, Jenny Rohrs, Jeremy Goff and me (Joy
Wolf).
Those who are not pictured are Jeff Lukas, Christy Edwards, and Ann Henson.
Several Park folks helped greatly with fieldwork in 1998 (Carl and Dan).
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