Posts Tagged ‘ecosystem’

posted by | on , , , , , , , , , , , , , , , , | Comments Off on Mosquito Misconceptions and Protecting Yourself from DC’s Skeeter Scourge

By Mayda Nathan, insect ecologist

DC’s mosquitoes are enough to drive a person crazy. Abundant and stealthy, they make enjoying the DC summertime a real challenge, and they can transmit some nasty diseases, to boot. But they’re a natural part of this swampy environment, probably playing some underappreciated but pivotal ecological role, so we should accept their annoying presence at our barbeques and in our gardens…right? Wrong.

As an insect ecologist, I have a dark fascination with these maddening fellow residents of our city. Over the years that I’ve lived here, I’ve read about our mosquitoes, talked to experts, and participated in a local monitoring program. I’ve run into many misconceptions about who these critters are, what they’re doing here, and the ways we can protect ourselves and stay sane during the summer months.

Misconception #1: There’s just one kind of mosquito in this region.

In North America, we have about 200 species of mosquito. A very small fraction of those bite humans (and, of those that do, it’s only the females who do the biting). There are 30+ different species of “DC mosquitoes.” They all depend on standing water to reproduce, but the type of water they want varies – for some species, only saltmarshes will do, while others insist on ephemeral pools in woodsy settings. Some species prefer the sorts of little pools of water that us humans are great at (unintentionally) providing, like in the form of abandoned tires and clogged gutters. Those are the species we tend to encounter most often in our neighborhoods.

Misconception #2: Mosquitoes are a natural part of this region’s ecosystems.

Yes, there are native mosquitoes here, but most mosquitoes in your DC yard are relative newcomers to the regional ecosystem. The most abundant, irritating mosquitoes in DC neighborhoods are of one species: Aedes albopictus, AKA the Asian tiger mosquito. As its name implies, this species is not from around here. Accidentally imported to North America sometime in the 1980s, the Asian tiger mosquito has taken a liking to its new digs and is now found throughout eastern North America, even becoming the most abundant mosquito in some cities.

We also have several non-native Culex mosquitoes in our midst (though they don’t seem to reach the same aggravating densities as the Asian tiger). Additionally, we have a new arrival. In 2011, Aedes aegypti, the yellow fever mosquito, was discovered in Capitol Hill.

Misconception #3: Bats and other predators in DC depend on mosquitoes for food.

Wouldn’t it be great if we could conscript our bat, bird, and spider friends to wage war on mosquitoes, on our behalf? Alas, while this may be true in wetlands and boreal zones, there is very little support for this idea in urban settings.

Bats in the DC area, for example, are almost certainly not mosquito-eating machines, hoovering up thousands of mosquitoes every night. For one, the Asian tiger mosquito is a day-flier, so its odds of encountering bats are low. Secondly, our bats probably focus their efforts on more rewarding insect prey; mosquitoes are like flying celery sticks, compared to the winged cheesesteaks that are moths and katydids. This is likely the case for many predators in our region; they will eat a mosquito but would probably rather eat something else.

Misconception #4: There’s no environmentally friendly way to control mosquitoes.

I get it – some of our past efforts to control mosquitoes, in the form of large-scale wetland drainage and DDT spraying, had environmental repercussions that are haunting us still. But there are quite a few things you and your neighbors can do to keep from getting bitten, and even to reduce the number of mosquitoes around your house, that have minimal impact on other species.

Defense tip 1: Protect your skin.

There’s an endless array of products that claim to repel mosquitoes, but only a very small number have repeatedly been shown to be effective. I’m only advocating for products that have stood up to rigorous scientific scrutiny. The consistent winner is DEET, followed closely by picaridin (a synthetic version of a molecule found in pepper plants). Oil of lemon eucalyptus has been shown to be effective, but it must be re-applied more frequently than DEET (every 6 hrs v. every 10 for DEET). Also, throw out your citronella sprays and candles. That stuff’s useless.

Defense tip 2: Stagnant water is the enemy.

Start by removing ALL standing water around your house – what the pros refer to as “tip-‘n-toss.” Asian tiger mosquitoes can breed in amazingly small quantities of water, so no potential container should go overlooked. In my neighborhood, some common sources are:

  • Planter saucers.
  • Backed-up gutters.
  • Trash and recycling cans with broken or missing lids; submit a request through DC 311 to have yours fixed/replaced, and in the meantime, drill a small hole in the bottom.
  • Those accordion-style gutter extenders that direct water away from a house; pop a nylon knee-high over the end to keep the mosquitoes from going inside.
  • In-ground drain lines; secure a piece of window screening over the opening to keep mosquitoes out.

If your yard has a fountain or something similar that you can’t empty, pick up some mosquitofish (Amazon will ship you live ones!) or Bti dunks or Bti bits. These latter products contain a strain of bacteria that are toxic to mosquitoes and a few close fly relatives, but are harmless to everyone else – you, your dog, birds, bees, butterflies, etc.

Defense tip 3: Go on the offensive – but spray only if you must.

If removing standing water and using an effective repellent don’t keep the mosquitoes at bay, you still have a few options – from the passive to the nuclear.

  • Gravid Aedes Traps, or GATs. These nifty contraptions use water to lure in female mosquitoes who are looking for a spot to lay their eggs. There’s a big caveat: the traps are only effective if most contiguous neighbors deploy them. It won’t hurt if you’re the only one on your block who has GATs in your yard, but it won’t help much, either. On the plus side, areas with more than 80 percent of households using GATs have seen remarkable declines in mosquito numbers.
  • Some commercial spraying companies offer “natural,” “garlic-based” alternative to insecticides. This product doesn’t kill mosquitoes; it merely repels them. Online reviews are positive. But it is pricey and needs to be applied frequently.
  • Commercial spraying operations – the nuclear option. If you’re pregnant or expect to become pregnant, or have an infant or someone else in your household who’s immunocompromised – that is, if someone in your home is particularly at risk from mosquito-borne diseases like West Nile virus or Zika – then you might want to consider this option. It works, but it works because it’s a serious pesticide being applied to the vegetation and foundation around your house.

* In order to preserve insect biodiversity, consider making commercial insecticide treatment of your property a last-choice option. The treatment often involves pyrethroids – a group of compounds that are generally safe for mammals and birds (yay), and that don’t stick around long in the environment (yay), but that are highly toxic to a broad swath of insects (boo). For effective mosquito-killing power, pyrethroids are sort of the least-bad option, but using them will wipe out a lot of the wonderful, harmless insect biodiversity you might otherwise get to experience in your yard.

Go forth, armed with mosquito knowledge, to enjoy your porch beers, barbecues, and backyard play dates. Hopefully this information will help keep you sane and healthy all summer long.

Mayda Nathan is completing her PhD at the University of Maryland, where she studies insect ecology. She has lived in Washington, DC for ten years, and loves the city – mosquitoes and all.

 

 

 

 

Photo 1: Aedes albopictus, the Asian tiger mosquito – frequent crasher of DC picnics, barbeques, and gardening sessions. Photo credit: James Gathany, CDC. Photo is in the public domain.
Photo 2: Species like the little brown bat will eat mosquitoes, but they don’t eat them exclusively, and they’re unlikely to encounter the day-flying mosquitoes that plague DC yards and parks. Photo credit: “Healthy little brown bat” by Ann Froschauer, USFWS, CC BY 2.0.
Photo 3: Citronella candles have been shown to be totally ineffective at repelling mosquitoes. Don’t waste your money; buy some DEET, picaridin, or oil of lemon eucalyptus, instead. Photo credit: “Citronella Kerzen” by Joho345 CC BY 4.0.
Photo 4: Clogged gutters: a common mosquito breeding site in cities like DC. Photo credit: “Gutter clog” by Eric Schmuttenmaer CC BY-SA 2.0

posted by | on , , , , , , | Comments Off on Get Outside, Feed Your Soul: Tips to Living Your Best Outdoor Life

By Sara Murrill, DC EcoWomen Board Member

Let’s face it, DC is a career-obsessed city. Our jobs here are intense; the grind is nonstop. There’s always more work to do.

Fortunately, there is a reprieve from the craziness. DC has an impressive amount of greenspace, with plenty of biking and running trails through trees and alongside creeks and rivers; spots where you can disappear into the woods and totally forget you are in the middle of our nation’s capital (save a distant siren). Many studies have shown how beneficial greenspace is to physical and mental health. In our overworked, over-connected society, it’s becoming more essential to unplug and immerse yourself in some therapeutic quality nature time.

As someone who has spent much of my career in national parks, I encourage everyone to reap the benefits of spending time in the great outdoors. Make sure you’re properly prepared and then get outside! Here are some tips to living your best outdoor life.

Explore every nature spot you can

From Rock Creek to Kenilworth Aquatic Gardens to the Capital Crescent Trail, the more you get out there and explore, the more you’ll realize what DC has to offer. Venture out regionally to nearby mountains for weekend trips. Discover world class landscapes and America’s stories by visiting national parks across the country.

You know what is the best thing about Vegas? It’s only two hours from the Grand Canyon. Anytime you go out of town on a work trip or to attend your millionth wedding of the year, research public lands nearby and tack on a visit!

Go off the beaten path

Not literally – please stay on the trail. The most popular places are popular for a reason; visit them to find out why. But the lesser known places are just as amazing even if they’re not as obviously glamorous. A backpack and a tent are a great investment for exploring more remote places. You’ll feel like it’s all your own.

Appreciate nature’s tiny details

Sitting in the same spot in the woods for 40 hours a week for entire summers taught me to really appreciate the subtleties in nature. How many water droplets are on that flower? Is that fluttering butterfly ever going to pause for a rest? Where’s that beetle going? What’s that weird growth thing on that tree? Do the squirrels that I see every day recognize me? Forget everything else and occupy your mind with nature’s curiosities.

Examine your own motives

Another yoga pose on a mountain peak? Are you doing a hike for yourself or for your Instagram? What do you want out of your time in nature? How might your experience change if you only focused on being present in the moment and immersing yourself fully in being outdoors?

Enjoy the natural soundscape

When I first moved to DC, I joined a Silent Hiking Meetup group. I still have no idea who those people were or why they joined – I never talked to them. Presumably, we all understood the power and enjoyment that intentionally tuning in to your natural surroundings can bring. Try it for yourself! If silence isn’t for you, please be mindful (especially in large groups) of your noise levels.

Take some time for yourself

If you can make some time alone for yourself outside, it’s the perfect setting for reflection and inner growth. Sitting by an endlessly babbling creek or staring up at majestic mountain peaks that make you feel like a tiny speck can help bring perspective and a sense of calmness. The peace you build through time spent in nature seeps its way into your normal life. Nature is therapeutic.

Respect ecosystems & wildlife

Please, learn and follow Leave No Trace principles. Many people harm ecosystems without even realizing it. When I lived in the backcountry of Yosemite, a beautiful black bear used to roam near the ranger campsite in the evenings. He minded his own business and we minded ours. One night, a park visitor broke the rules and slept with food in his tent, and our bear took a swipe at the tent looking for a snack. No one got hurt, but this bear was now a “problem bear” and had to be hazed each night so that he wouldn’t return to the area and potentially cause harm. Know and follow all park rules. Respect all wildlife by keeping your distance and do NOT feed or touch them. You are the visitor; this is their home.

Learn, share, and protect!

Check out a ranger-led talk, read up on the park’s history, and learn more about the incredible resource that you’re visiting. The more you learn, the more you’ll come to value these irreplaceable treasures. Share your experience and invite others to join along – preserving these special places will take effort from all of us!

 

Sara Murrill is a DC EcoWomen Board Member. She currently works at the National Park Foundation, the official charitable partner of the National Park Service. Previously, she was a contracted field researcher for the National Park Service.

Captions: Pic 1: Who needs a gym when you can run these trails? Rock Creek Park, Washington, DC; Pic 2: Work trip summer 2018: solo sunrise hike in Rocky Mountain National Park, CO; Pic 3: Camping in Dolly Sods Wilderness, Monongahela National Forest, WV; Pic 4: An Avalanche Lily – a bit droopy from the morning dew. Mount Rainier National Park, WA; Pic 5: Me and a friend doing a double arch at the double arch. Creative, huh? Arches National Park,  UT; Pic 6: Channel your inner mountain goat and get outside! Arapaho-Roosevelt National Forest, CO.