Hagerman National Wildlife Refuge – After The Flood

 by Laurie Sheppard

May, 2017 marks two years since heavy rains caused damaging flooding at Hagerman National Wildlife Refuge and other parts of north Texas. By May 10, 2015, many roads on the refuge were impassable and public access was curtailed. Ultimately, 9,000 of the refuge’s 11,320 acres were under water. It was August before the main roads were fully exposed and repairs could begin. At its worst, parts of the refuge were under as much as 24 feet of water, displacing wildlife and causing permanent changes to some habitats.

Rainfall totals along the Red River can vary greatly and periods of flood often follow seasons of drought. Such was the case starting in 2015. Three years of markedly reduced rainfall had left Lake Texoma’s conservation pool several feet below normal but spring rains filled the lake and kept on coming. The water receded in the fall, but a second closure of the refuge occurred in December, 2015 and a third in May and June, 2016.

Flooding can have a positive impact on fisheries by bringing water to areas of woody or herbaceous habitat for fish to feed and spawn. The spring floods of 2015 may have been too late for spawning, but observations by anglers seem to indicate an increase in survival by some valued species. On the other hand, some of the larger sport fish were released downstream when the Denison Dam floodgates were open for several weeks. Flooding also brings with it a large influx of sediment, filling in portions of the lake creating shallows where Carp and Gar species flourish, but also adding nutrients that fuel the microscopic plants and animals at the base of the aquatic food chain.

The deer population at Hagerman NWR appeared to move to higher ground in the summer of 2015 and then return as the waters receded. The refuge performs a deer census each fall, following the same route over multiple days, so they have decades of data with which to compare. The deer count in 2015 did not vary greatly from previous years, which was very encouraging. However, in 2016, the flooding occurred at birthing time and the number of surviving fawns identified was much lower.

Birders noticed a reduction in raptors in the winter of 2015-16. Barred Owls that had previously nested in known areas were no longer seen or heard but seem to be gradually returning. The Friends of Hagerman NWR organization has tracked Bluebird nesting for several years. Volunteers check nest boxes weekly throughout the refuge. In 2014, 272 Eastern Bluebirds fledged. Nest box monitoring was halted mid-season in 2015 when the nesting areas flooded. Some nest boxes spent weeks underwater but when access was restored volunteers saw others with new nests built on top of old nests. Only 103 fledglings were counted in 2015, and with a smaller flood in 2016, 152 bluebirds fledged.

The largest impact identified in these past two years is to hardwoods, especially oak trees, which notoriously don’t do well with prolonged “wet feet”. Many trees have died, changing the landscape, which will affect the mix of wildlife in the long term. The public responded to a plea for acorns in the fall of 2015 and thousands were planted by volunteers, but then more floods occurred. It will be a few more years before it is well known what the long term impacts will be. Change is constant but nature will prevail.

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