A Northwoods Almanac for June 25 – July 8, 2010
We received nearly four inches of rain in Manitowish during the first half of June, a welcome respite from the severe drought which has impacted our lakes and rivers since 2003. This drought is the worst in the historical record for north central Wisconsin; however, it has not been uniform in its effects. First, weather stations at various northern Wisconsin sites have recorded dramatically different local precipitation totals:
Location Precipitation Deficit from 2003 - 2010
Rest Lake - 59.4 inches
Rice Reservoir - 55.9 inches
Rhinelander - 47.4 inches
Wausau - 39.5 inches
Minocqua Dam - 37.0 inches
Lac Vieux Desert - 24.7 inches
Eagle River - 19.24 inches
Phelps - 17.2 inches
Thus, the Manitowish Chain of Lakes and the Manitowish River have experienced the worst local effects of the drought, which confirms the local belief that storms have been tracking just north or south of us for many years.
Second, the drought has impacted distinct types of lakes very differently. Lakes with no inlet or outlet streams – those that get their water solely from precipitation and ground water – have fared much worse. Water levels in these “seepage” lakes have historically fluctuated between 2 ½ and 11 feet. Lakes that get their water from streams and rivers (“drainage” lakes), as well as receiving water from precipitation and groundwater, have historically fluctuated far less – between 1 ½ feet and 4 feet. Many drainage lakes in our area have only dropped 1 or 2 feet during this drought, while many seepage lakes are at least 6 feet down.
Third, lakes that are high in the landscape have fared worse than those lower in the landscape. Since groundwater flows downhill, lakes at high elevations receive very little groundwater compared to lakes lower in the landscape that get the benefit of lots of water draining downhill and into their basins.
Fourth, humans impact water levels in a drought, too, though in our area the effects are unclear. In central Wisconsin, the pumping of irrigation water onto farm fields has substantially lowered groundwater levels. In the Lakeland area, we don’t have that intensive agricultural use to draw our water tables down. However, one wonders what the impacts are of cranberry marshes that draw water directly out of rivers and lakes.
Dams also alter water levels, for better or worse. The Manitowish Chain, for instance, is drawn down 3 ½ feet every winter to protect docks. As of June 1, water levels had only come up 1 foot. If the Chain had only been drawn down 1 foot last fall, it would have been at full pool in late May.
Drawdowns at dams are always a major problem when drought occurs, given that the public’s water must be shared with wildlife, plants, and people throughout the watershed.
The far more difficult issue in this drought is to determine how long it will take to refill the many seepage lakes in our area that are way down. Since every seepage lake is different in terms of its inflow of groundwater, limnologists are unable to say how much rain we’ll need above our annual average to bring all of the lakes back up to “normal”. Many people have docks and boathouses that are now literally hundreds of feet away from water, and the problem, of course, spills over into wildlife and plant communities. The shoreline branches and logs that supported abundant fish, insect, and amphibian communities are high and dry, reducing the reproduction and growth rates of many species. Beaver lodges and bank dens are completely out of the water; waterfowl nesting along shorelines are impacted as waters continue to recede; frogs that hatched from eggs laid in marshes or woodland pools that have dried up won’t make it.
Some good has also come of the low water. For instance, rusty crayfish are faring poorly as the logs they utilize for cover in shallow water are no longer available. Plants that are adapted to germinating on exposed shorelands during a drought are singing halleluiah. Unfortunately, non-native plant species often are best adapted to disturbed soils, so they may win the race to colonize the new open ground.
Nature always operates under a dynamic profit-loss statement, with the decline of some species providing opportunities for others. A fire, a flood, a drought – any natural disturbance – has a host of species that are adapted to the “disaster”. In fact, a number of species require powerful natural disturbances to occur.
As I’m writing this on the evening of summer solstice, it’s dark and a thunderstorm is marching through. Every drop it gives us will help, but how long will the road back to recovery take?
During our last frog count on 5/25, we heard whip-poor-wills calling at three of the ten sites we visited. At one site near Nichols Lake, we’ve heard a whip-poor-will calling for at least a decade. It’s a sound that we are thankful to hear every year, though we are equally thankful that one doesn’t sing below our window. Their extraordinarily loud and repetitive call could easily drive someone to dark thoughts.
A ground-nesting species, whip-poor-wills lay their clutch of two eggs directly on the leaf litter of the forest floor where the adults remain motionless on the nest or on a roost site during the day. At dusk, they begin actively foraging for flying insects, and on moonlit nights, they catch moths and beetles all night long. The hatching of their chicks seems to be closely tied to when the full moon will occur, so the parents can forage all night and supply the extra energy needed for their growing chicks.
Dry forests with little or no underbrush and a high degree of openness appear to be their optimal habitat, habitat we seem to have in abundance. However, whip-poor-will populations appear to be declining gradually, though their presence has been poorly sampled over the years because most breeding bird surveys occur in the early morning when whip-poor-wills are quiet and nearly impossible to see. Still, most ornithologists agree that today they occupy less of their available breeding range due to habitat loss from agriculture. The closing of forest openings due to growth and succession of trees also appears to be a major cause. Grazing by farm animals in open woodlands also causes whip-poor-wills to fail to return to those areas because of loss of understory nesting cover.
On the other hand, too many plants in the understory can be equally problematic, particularly when invasive shrubs like honeysuckle and buckthorn take over. The appropriate balance of food and cover in a habitat, as always, is the key.
Whip-poor-wills actually sing 100 to 200 different songs, though few of us have the endurance to differentiate their nonstop songs from one another. The males sure must want to impress the lady whip-poor-wills, though one could argue that perhaps they need an adaptation lesson in quality over quantity.
Jody Bognar sent me a lovely picture of a luna moth a few weeks ago. I hope the paper is able to print her picture in color, because luna moths rank right up there with some of the most stunningly colored creatures in North America.
Batty Volunteers Needed
The WDNR is trying to collect as much baseline data as it can on bat populations in Wisconsin and needs your help. A disease called “white-nose syndrome” is devastating bat populations in the eastern U. S., causing “the most precipitous wildlife decline in the past century in North America,” according to biologists. This fungal disease causes bats to awaken more often during hibernation and use up their stored fat reserves, leading to their death by starvation or freezing. The syndrome has killed more than a million bats in fourteen states since 2006, and will very likely make its way into Wisconsin in the next few years.
Thus the rush to get baseline data, so we at least know what the bat populations were before we lose many of them. A citizen monitoring program has been established utilizing a recorder that makes the echolocation calls of bats audible and also visible as a sonogram. One method to capture this data is for volunteers to slowly paddle or quietly motor around the circumference of their lakes after dark, press a button on the device to save the information whenever a bat call is registered, and then go home and download the data onto a computer and e-mail it to Madison.
The process is very simple, and I’ve had a number of people tell me it’s great fun as well – most folks were surprised to learn the bats were so active and so noisy! Given the positive ecological value of bats – they eat mosquitoes – their presence is highly desirable.
I’d love to see every lake association take this and run with it. To volunteer, call wildlife biologist Linda Winn in Woodruff at 365-5211, extension 207, or call the North Lakeland Discovery Center at 543-2085. A training session will be held at the Discovery Center on July 21.
The full moon – the Strawberry or Rose Moon according to tribal traditions – will occur on 6/26. A partial lunar eclipse, the first of two lunar eclipses in 2010, will also occur this night, though it won’t be visible in northern Wisconsin. It will be visible after sunset from Australia and eastern Asia if you wish to hop a plane. Or it can be seen before sunrise over western North and South America, but the moon will set just as the eclipse starts to become interesting.
The second lunar eclipse will be a total eclipse on 12/21, winter solstice, and that one we’ll apparently see.
July 2nd marks the mid-point in the calendar year, and though the solstice occurred back on 6/21, the sun finally begins setting one minute earlier on this date. The Earth reaches its farthest point (its “aphelion”) from the sun on 7/6, some 94.5 million miles away. Nearly six months ago, on January 2nd, we were a mere 91.4 million miles away. It may seem strange that it was coldest when we were closest to the sun, and it will be warmest when we’re farthest, but the degree of tilt of the earth toward or away from the sun is the important number, not the distance away.