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(Lori) Within Grand Canyon National Park's 1.2 million acres
there are over 1,750 plant species. But only one tiny plant is federally listed as endangered.
Hi, I'm Lori Makarick, the park's Vegetation Program Manager,
and I'm here to tell you the story about that plant—the sentry milk-vetch.
Little has been known about the sentry milk-vetch, even though the plant itself has been known
for more than 100 years. Marcus E. Jones was an early scientist and
explorer of the western US, and he's actually the person credited with discovering sentry-milk-vetch.
That was in 1903. He described the plant as "common" in
Grand Canyon, but 40 years later, Rupert Barneby, a very noted botanist and actually an expert
in milk vetches, reported that the plant was "of great rarity" in the park.
Sentry milk-vetch is a tiny, perennial herb that grows in a mat about an inch high and
up to 8 inches across. It's endemic, or only grows in Grand Canyon. It occurs within
25 feet of the rim, and it grows pretty much just on Kaibab limestone. It has a thick tap root
that allows it to penetrate that solid surface to reach the moisture underneath.
It has compound leaves, and, in the spring, it bears tiny lavender flowers.
Although the plant produces a lot of seeds, few germinate, and even fewer actually survive
to maturity. Those that do are threatened by habitat loss, climate change, and drought.
It's due to these factors that this plant is extremely vulnerable to extinction.
Long term monitoring revealed that the population of sentry milk-vetch was reduced to just a
small area at Maricopa Point, which is on the south rim. The reduction of the species
range, and possibly the loss of populations were likely due to trampling by visitors.
The visitors are focused on the view and the vast expanse of Grand Canyon, not at the
tiny little plants that are right below their feet. Park management took pro-active measures to
protect the plant, and they actually fenced off the habitat at Maricopa Point to minimize
impacts to the population. In 1990, the US Fish and Wildlife Service listed the
sentry milk-vetch as endangered under the Endangered Species Act.
The Endangered Species Act mandates that recovery plans must be completed and implemented for
all species that are listed. The sentry milk-vetch recovery plan was completed in 2006.
There are a lot of criteria in the recovery plan, and the most important ones are having
four self-sustaining populations of at least a thousand individuals. The ultimate goal
is to completely de-list the species so that it's no longer considered endangered.
In order to do that we need eight populations of a thousand individuals, and we need to
know that they can survive into the future without our assistance.
(Martha) Hello, I'm Martha Hahn. I'm the Chief
of Science and Resource Management here at Grand Canyon National Park. I wanted to tell
you a little bit about the importance of the sentry milk-vetch and the role it plays here
at Grand Canyon. Uh, it is a very small plant that not many visitors know about, let alone
would they see. However this restoration project is very important in terms of bringing back
the species and the balance of the ecosystem processes as they interrelate with plants,
animals and physical environment.
(Lori) The Division of Science and Resource Management
at Grand Canyon National Park has partnered with the US Fish and Wildlife Service, the
Arboretum at Flagstaff, and our fundraising partner, the Grand Canyon Association,
to implement these important recovery plan actions. The goal, obviously, is to preserve, protect
and facilitate the recovery of this endangered species.
One dramatic step in the park's long term commitment to recover sentry milk-vetch was
to remove the entire parking lot at Maricopa Point. The area was restored with native plant
species and a section was set aside for sentry milk-vetch reintroduction.
Reintroduction of sentry milk-vetch at Maricopa Point involved recreating the unique soil
characteristics that will support the plant, planting companion species, and planting both
sentry milk-vetch seeds and plants that were propagated by the park in an ex situ population.
In 2009, the park and Grand Canyon Association received US Fish and Wildlife Service funding
to construct a passive solar greenhouse. In 2010, the first GRCA greenhouse plants
started flowering in February. This was a major milestone and we were really proud to
get that word out there. To produce seed, we actually had people hand pollinating the
flowers by squeezing them open with tweezers and collecting the pollen with a fine paintbrush.
And then in July that year, the first five greenhouse-grown sentry milk-vetch plants
were planted in the ground at Maricopa Point, and to date, all of these plants have survived.
In the spring of 2011 we started seed trials in the field. The seeds were covered with
a variety of native soil, and protected with collars and landscape material to allow the
sunlight and water in, but to protect them from wind and insect pests.
In July, we had the first large planting. We put out 80 plants and 240 seeds in the
ground at the site at Maricopa Point.
Since the 1990 listing, two more populations of sentry milk-vetch have been discovered
and confirmed on the South Rim. At this point we know we've got at least 2,500 plants
that are living in the wild at Grand Canyon. In 2010 we found that we've got about fifty
percent of our plants still alive and thriving in the ground. The seeds have also continued
to survive. This year we've had two different flowering times. One in April, and one in October.
The first seedling progeny of 2011 plantings were discovered this past year.
We have at least 50 tiny seedlings that were produced by the plants that we planted
in the field which is a huge success for the long-term recovery of the species.
With two solid populations currently established, what we need to do now is select two new sites
with suitable habitat and use what we've learned from previous work to begin planting
plants and seeds in the field. We also continue to keep the public engaged and informed through
a variety of media, and we continue to involve volunteers with every part of our effort.
(Martha) You know, it's really exciting to see the,
the accomplishment that has occurred with over thousands and thousands of hours of work from
our technical specialists, volunteers and professionals here at Grand Canyon. And just
to see this and, and to see the milestone that we have reached in the very first recovery
of this plant species.
(Lori) Park staff and many partners have made incredible gains
to the protection and long term recovery of sentry milk-vetch,
and we are all committed to keeping the momentum going.
We want to see these populations stable and able to withstand the challenges of the future.
By 2016, the year the National Park Service celebrates its 100th anniversary as an agency, we hope
to highlight this project as a success -- celebrating that we've learned enough to take a species
from the brink of extinction to the path of survival.