Don’t try to tell Nancy Pau, Gary Burke, Matt Poole or Graham Taylor that winter is not a bona fide natural disturbance.


They are, respectively, wildlife biologist, engineering equipment operator, visitor services manager and project leader at Parker River National Wildlife Refuge in Massachusetts.


They know that winter is a profound disturbance that has varied effects on wildlife, habitat, infrastructure and visitors at the barrier island refuge.


Nancy Pau, the biologist, points out winter’s beneficial effects on habitat and the challenges it poses for wildlife.


“Winter and its thaw are very important to the salt marsh’s ability to grow in elevation over time,” she says. “Much of the salt marsh is frozen over the winter, including portions of tidal creeks. As the tides ebb and flood, it pushes ice chunks onto the marsh surface. These ice chunks have sediment—mainly mud from creek bottoms—and various organic matter. This is believed to be a main way that marshes get sediments, which is very important to it being able to grow and accumulate, especially with rising sea levels.”


She notes that spring snowmelt also fills vernal pools in the refuge’s dunes. Those pools, which are the only source of freshwater for wildlife on the island, provide breeding habitat for amphibians and reptiles. And winter precipitation fills the refuge’s three freshwater impoundments.


On the minus side, Pau says, winter means limited and lower nutritional food resources for wildlife as well as less foliage cover and thus more vulnerability to predation.And wind and wave action associated with Nor’easter storms of increasing intensity erode beaches in a way that, combined with other factors, can harm habitat.


Gary Burke, the equipment operator, knows all too well the toll winter takes on infrastructure. Freezing and thawing moisture causes frost heaves and potholes in refuge roads. Snow removal, grading of gravel and increased heavy equipment fuel and facility utility consumption make winter expensive for the refuge. Winter restricts projects such as boardwalk, trail and sign maintenance.


Plus, Burke says, his least favorite aspects of winter are “working outside in extreme cold on equipment that has broken down” and “a snowstorm on a weekend.”


Matt Poole, the visitor services manager, dislikes that winter reduces the number of people who come to the refuge, but he says the season is “a time of unique beauty, particularly when the marsh and dunes are festooned with a blanket of snow.”


And Poole likes that “ongoing Web–based communications about current or new bird sightings can significantly influence visitation in a positive direction. For instance, if a snowy owl is reported to have been seen on the refuge, the word spreads like wildfire.”


Graham Taylor, the project leader, says the most difficult management challenges winter poses are disruptions of facilities operations, postponed partner meetings and refuge closures for dangerous conditions.


However, he says, “I think the biggest plus is that the weather itself—snow, cold temperatures, etc.—help shape the various habitats here for the wildlife seasons to come: migration and breeding. Heavy snows can provide the freshwater needed for our inter–dunal swales and seasonal wetlands for the Eastern spadefoot toad [which hibernates on the refuge in winter] as well as our managed impoundments. The winter storms can also improve nesting habitat for beach nesting birds, such as the piping plover and least tern. Winter also keeps all but the hardiest visitors away, which helps reduces disturbance to wildlife at one of the most stressful times of their year.”


There’s one thing Taylor really doesn’t like, though: “A late–season snow, especially after mid–March, when spring is starting to show signs of arriving.”