Drought, even a moderate drought, has an immediate, noticeable impact on the landscape.
It’s officially autumn, but you wouldn’t know by the weather forecast.
In central Kentucky daytime, high temperatures have averaged about 10 degrees above normal in recents weeks. On September 23, a rain “event” of 0.02 inches was reported at the Louisville International Airport weather station, ending a 27-day dry spell, the longest without measurable rainfall in the city in 20 years.
Freshwater muscles appear on banks as water recedes during dought (Photo from Wikipedia Commons)
Louisville, and most of central Kentucky, has endured 72 days and counting at 90 degrees Fahrenheit, or hotter, making 2019 one of the hottest on record.
The dry, windy conditions exacerbate seasonal allergies. Molds are lifted from the soil and carried in the wind. Ragweed, which causes so much suffering in the fall, goes into “death mode” during a drought and cranks out the pollen.
Since there’s been little or no rain, the air never really clears.
In town, homeowners have been watering their lawns, shrubs and flowers. Ornamental trees like birch, crab apple and dogwood are noticeably stressed. The leaves on these and many other trees have begun to dry and fall prematurely, without ever changing color.
But, in rural fields, forests and waterways, there are no sprinklers or garden hoses to come to the rescue. Drought is a matter of life and death for fish and wildlife. The impacts can become severe, if the drought is not broken, or first frosts come later than normal
Here’s some details on the impacts of drought:
• When vegetation dies back wildlife is deprived of food and cover.
Grasses become unpalatable, and late nesting by rabbits and birds may become less successful because of high temperatures and low moisture.
The reduction in plant growth results in less available hiding cover, which can increase predation by foxes, coyotes and raptors.
Fewer flowers mean bees can’t find food, and there are fewer insects, a major food source for birds and small mammals.
• During late summer and early fall there’s always a risk of wildfires, caused by lightning strikes, or carelessness, such as a cigarette butt flicked out the window of a passing automobile or an unattended campfire. Drought greatly increases the likelihood of numerous outbreaks of wildfires, despite burn bans being issued.
water in ponds, small lakes and streams become stagnant as temperatures increase due to lack of rain (Photo from KDFWR)
• Drought affects the abundance and quality of hard and soft mast crops.
Acorns, beech and hickory nuts, and persimmons shrivel up, depriving forest wildlife, particularly wild turkeys, deer and squirrels, and small mammals, of a valuable high-energy source. As a result, they may go into the winter with lower fat reserves.
• Drought may cause some wildlife to change their home ranges in an effort to find water, and create conditions that can impact their health and cause disease outbreaks.
In the Great Lakes states and prairie regions in the upper Midwest where waterfowl are staging for their fall migrations southward, high temperatures and low rainfall can contribute to outbreaks of avian botulism.
The anaerobic bacteria Clostridium botulinum typically resides dormant in the soil, but under the right conditions, can replicate and produce toxins in wetlands.
Waterfowl ingest the toxins through feeding on invertebrates or drinking infected water. Species that are most impacted by botulism outbreaks are mallards, wood ducks, and teal and several species of waterbirds, including great blue herons.
• Epizootic Hemorrhagic Disease (EHD), intensified by drought, affects deer and other wild ruminants throughout the eastern half of the U.S. and southern Canada. Low water conditions in small streams concentrate deer around remaining water holes, putting them at a higher risk for exposure.
The infectious viral disease is spread by several species of flying insects in the genus Culicoides. A 1/10-inch biting midge, Culicoides sonorensis, is the primary vector in Kentucky.
Deer infected with EHD usually die in eight to 36 hours following the onset of observable signs, which include labored breathing, excessive salivation, no fear of humans, lameness, swelling of the head, neck or eyelids, or blue tissue coloration around their mouth and nose.
High fever causes deer to seek out water. That’s why carcasses are usually found in or near lakes, ponds or streams.
Outbreaks of Epizootic Hemorrhagic Disease (EHD) are intensified by drought (KyForward file photo)
On August 22, the Kentucky Department of Fish and Wildlife Resources (KDFWR) reported the state’s first case of EHD in 2019, confirmed by Murray State University’s Breathitt Veterinary Center.
KDFWR is investigating other possible cases involving 22 deer in 11 counties and expects the number could grow in the coming weeks.
This year’s outbreak is the sixth in the past 10 years in Kentucky, including outbreaks in 2007, 2010, 2012, 2015 and 2017.
The 2007 outbreak was the worst since Kentucky re-established deer herds in all 120 counties. By late September of that year 2,262 deer were suspected of dying from EHD, with reports from 96 counties.
Outbreaks of hemorrhagic disease generally last from late summer until the first hard frost of the year kills the virus-carrying flies.
• Prolonged drought can have a big impact on both aquatic and terrestrial life that depends on the water in streams, ponds and lakes.
Small streams may completely dry up, killing minnows and other aquatic life, and depriving birds and mammals of their local water source. Freshwater mussels can be left high and dry if river levels are substantially lowered.
The water in ponds, small lakes and streams become stagnant as temperatures increase due to lack of rain and low inflow. This causes levels of dissolved oxygen to decline, putting fish and other aquatic life at risk. The situation is made worse if there is an algae bloom or shoreline aquatic vegetation dies back since oxygen in the water is consumed as this organic material decays.
In large reservoirs, there’s also a risk of fish kills, especially for cool water species such as walleye, striped bass and trout, which have specific temperature requirements. As the heat and lack of rain intensify, water temperatures climb and dissolved oxygen levels deteriorate.
Cool water species become stressed, then eventually die if the oxygen levels in the water at their preferred temperature range become exhausted.
The bottom line is, cooler temperatures and rain are needed now to avoid severe damage to fish and wildlife.
Art Lander Jr. is outdoors editor for KyForward. He is a native Kentuckian, a graduate of Western Kentucky University and a life-long hunter, angler, gardener and nature enthusiast. He has worked as a newspaper columnist, magazine journalist and author and is a former staff writer for Kentucky Afield Magazine, editor of the annual Kentucky Hunting & Trapping Guide and Kentucky Spring Hunting Guide, and co-writer of the Kentucky Afield Outdoors newspaper column.
