Resource Ramblings 2005-07

Bison Bull

NPS Photo

Natural Resource Management

Ladies and gentlemen, July and August are the heavy months for bison to participate in the rut. At this time, they have other things on their mind than your comfort and safety. Likewise, they are not particularly concerned with the needs or desires of our visitors. Please be careful when near bison at this time and give them a wide birth. If you get this look, beware!

Park Precipitation

• Although the last few years have been a bit dry, the 2005 precipitation has been both welcome and needed. As of now:
• For the calendar year (January-June), the Park has received 11.83 inches. The 53 year January-June average is 10.06, which means the Park is 1.77 inches above 53 year January-June average.
• The full calendar year (January-December) average is 17.81 inches of precipitation. Therefore, the Park needs an additional 5.98 inches to reach that average.
• The 53 average precipitation for July is 2.48 inches. Thus far, the Park has received 0.35 inches, which means we need an additional 2.13 inches to reach the 53 year average for the month. July is a very important precipitation month for the Park.
• Over the past 12 months (July 2004-June 2005) the Park has received 20.26 inches, matching the 53 year average.

The Vegetative Growth Year (VGY) encompasses the months of October through the following September. To date, the Park has received 13.36 inches of precipitation for the VGY. The 53 year VGY average is 12.2 inches. – Barb Muenchau

Resource Management Volunteer

Tom McBride, volunteer, is working on a variety of projects such as removing stakes from tiger salamander inventories, asphalt removal, exotic species control, boundary fence surveys, and photography. You no doubt have seen the McBride’s motor home in the housing area with the rafting armadillos. Say hay to him when you get the chance.

Beauties or Beasts?

This is the time of year when thistles add beautiful shades of pink, lavender, and purple to the park’s prairie landscape. However, beauty is in the eye of the beholder. Thistles, with their prickly stems and leaves, are not always a welcome sight. Four thistle species occurring at the park are native to this area, four are not. The native species are wavy leaf (Cirsium undulatum), Flodmann’s (Cirsium flodmanii), Drummond’s (Cirsium drummondii), and yellowspine thistle (Cirsium ochrocentrum). The exotic thistles are Canada thistle (Cirsium arvense), musk thistle (Carduus nutans), bull thistle (Cirsium vulgare), and Scotch thistle (Onopordum acanthium).

 

Native Thistles:

 

Wavy Leaf Thistle - Cirsium undulatum
Common throughout the park

Photo by Jennifer Ackerfield

 

Flodmann’s Thistle - Cirsium flodmanii
Common throughout the park

NPS Photo

 

Yellowspine Thistle - Cirsium ochrocentrum
A few are founds in the Norbeck dogtown, along Highways 87 and 385

 

Drummond’s  Thistle - Cirsium drummondii
Only reported from the Blacktail Spring Drainage

NPS Photo

 

Exotic Thistles:

 

Bull Thistle - Cirsium vulgare
Scattered locations in park

NPS Photo

 

Scotch Thistle - Onopordum acanthium
Mixing Circle Area

NPS Photo

 

Musk Thistle - Carduus nutans
Mixing Circle Area

NPS Photo

 

Canada Thistle - Cirsium arvense
Found in prairie dog towns, drainages and disturbed areas

NPS Photo

 

Some of the clues that help with identification of thistles are: Foliage color (wavyleaf, Flodman’s and Scotch are grayish green); height (Scotch grows several feet tall), leaf shape (bull thistle leaves have a distinctive shape with long, pointed leaf terminals); or, flower head formation and shape (musk thistle has leafy bracts, as opposed to spiny bracts, below its nodding flowers). Canada thistle, the most invasive thistle species, is the easiest to identify. It tends to grow in dense stands, and produces many small flowers at the end of each stem. Other thistles at the park produce much larger flowers, usually one to a stem, and do not create extensive clones. – Marie Curtin.

Comments and feedback about Resource Ramblings are encouraged and can be made to Dan Foster, in person, or via email.