Wednesday, September 28, 2011

Effects of Drought at Refuge

Photo: Harris Creek bed, looking north from Wildlife Drive at the bridge.

Visitors who have not been to the Refuge recently will be amazed at the changes in the landscape brought about by the drought. We contacted Refuge Manager Kathy Whaley, Dr. Wayne Meyer, and Dr. George Diggs, while doing research for a presentation on the impact of the drought on Hagerman National Wildlife Refuge. Here is what we learned.

Whaley told us, "If you walk or drive through Hagerman NWR, it is easy to see that the Texas drought has not bypassed the Refuge. Wetlands are dry. the lake is at a 32-year low. Hiking trails are full of cracks in the soil - some more than two feet deep. Shorebirds passing through this fall will find mudflats, but they will be much farther out than normal, making the birds very difficult to see."

She continued, " The ditch we normally pump water from to fill some impoundments is dry. The Refuge staff is working hard to install the water pipeline from Big Mineral Creek to all water to be pumped into the wetlands along Wildlife Drive, but it is a slow, time-consuming process."

"So far," Whaley reported, "staff has rescued two wading birds and one deer that were stuck in the mud. One of the birds, a Snowy Egret, actually had a turtle hanging onto its right leg. Assistant Refuge Manager Rick Cantu found this out while working to free the bird when he grabbed the turtle that was buried in the mud, trying to free the bird. The good news is that Rick still has all his fingers and we saw both legs and two feet as the Egret flew away. The only loser of the day was the turtle."

Whaley said that the lake level is dropping by as much as one inch per day. Ponds, if not already dry, are also getting drier and wildlife are having to travel to the lakeshore to get water. Feral hogs are creating wallows in creek beds where a few pockets of mud remain. Raccoon, bobcat, coyote, and deer tracks are visible along many areas that have not yet been covered by growing grasses and weeds. Plants are suffering - many trees and shrubs are turning brown and only time will tell if they have simply gone dormant or are dying. Numerous grasses and wildflowers are now dormant also, leaving many shades of tans, grays, and browns throughout the Refuge.

Whaley added, "Rain will come again - but when is anyone's guess. There is no doubt that the lack of precipitation will have a negative impact on some species and their numbers will decline. But native wildlife have evolved to withstand drought, and for the most part, they will survive. With any luck, non-native species such as the feral hog will also be impacted and perhaps reproduce in fewer numbers."

Dr. Wayne Meyer, Associate Professor of Biology at Austin College, added, "Drought has certainly affected the food supply and several summer breeding birds stopped early this year. The lake still provides drinking water for most species, so the real crunch as been the loss of seed crops and fruits, plus the insects that would have been feeding on green plants. Since the drought is not terribly widespread (I know, Texans want everything to be big, but east of north of us there has been excess rain), migratory animals like birds and insects will probably not be too badly affected. I expect their numbers to be near normal next year."

Like Whaley, Meyer says, "I'd like to think that the feral hogs will decline a bit, but I'm not holding my breath. Deer have been more visible lately, presumably because they are having to come to the lake or ponds that still hold water to drink every day. I don't know how their food supply has been affected but I should think they would be able to find sufficient browse around the the water sources. There may be a bigger dip in their numbers just because there is less food scattered across the drier parts of the Refuge.

Meyer added, "By the way, we are expecting a bumper crop of waterfowl this year; the prairie potholes got lots of rain and duck and goose reproduction was high. The question will be whether they will be able to find enough forage to make it through the winter. If Lake Texoma rises over the next few months to inundate all the dry ponds that are now full of smartweed, it will be a fabulous year for waterfowl - but if the lake level does not go back up, the waterfowl will probably have to go elsewhere by the end of December, much as they did last winter."

The third person we contacted, Dr. George Diggs, Professor of Biology at Austin College, pointed out that droughts occur with some frequency on the long term-scale, referring to the Dust Bowl ear and the bad drought of the 1950's. "Plants in this area therefore must have adapted for such occurrences. This adaptation does not rule out tree death or even the elimination of some species from certain areas or a dramatic decrease in animal populations."

Diggs continued, "When this ecosystem was intact ( a couple of hundred years ago) such occurrences would probably not have had significant long-term consequences because the ecosystem had enough resilience to recover over time. However, now, with so little native vegetation left and much of the best habitat converted to a variety of uses by humans, drought damage to the small remnants of native vegetation may have more serious consequences. Most of the habitat at the Refuge is so modified by natural conditions that I simply don't know what effect the drought will have."

On September 18, the elevation for Lake Texoma was 609.95'. Lake level information is available at

For Refuge information see the official website, and for information on the Friends, see

Photo by Dick Malnory

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