For the Conservation Curious

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Is There a Humane Way to Deal With Invasive Animals? May 29, 2014

I read an article today ( about how the Chesapeake Bay Nutria Eradication Program is working well, and that the people involved in the program may actually succeed in removing all these large, invasive rodents from the Bay. It also mentions the success people have had with eradicating the invasive mute swan from the region. As someone who worked on invasive species issues for many years, albeit mostly related to plants, I applaud the efforts of these folks and am excited for their success story.

However, the animal lover in me cringes a little bit when I read articles like this, especially when they describe how the nutria are trapped and killed. The traps are similar to what people use to trap beavers for their pelts… the animal is snared by the leg and drowned. I’ve never agreed with how beavers are trapped, so I cannot agree with their use here, even if nutria are highly destructive to the wetland and marsh habitats they live in. There has to be a move humane way to do this.


Many animal rights activists oppose the culling of invasive animals on the grounds that the practice is inhumane. When looking at the issue from the 40,000 feet view, I disagree with them. Invasive species cause significant damage to habitats, in turn negatively affecting and sometimes killing other, native wildlife. Most invasives are here because of foolish or unintended consequences of human actions, so I feel that it is our duty to do something about them. But it’s how we do something about them that I may have an issue with. I used to be very opposed to herbicides, no matter what. I thought of them as a poison with which we contaminate the earth. Yet as I learned more through my job, I came to realize that sometimes herbicides are the only solution to eliminating certain invasive plant species. Herbicides shouldn’t ever be the only line of defense, and hopefully aren’t the first choice in many situations, but they do have their place.

So it is with invasive animal control. Think of the Burmese pythons that are taking over the Everglades. These are long, strong, animal eating machines. Should we just let them slither their way across the state of Florida? No, I don’t think so. The same goes for nutria, mute swans, feral hogs, snakehead fish, Asian carp, and a whole host of other invasive animal species in the U.S. Yet how we control these animals says a lot about how we treat animals in general. If someone has no problem drowning a beaver for its pelt, then of course they have no problem drowning a nuisance species by the same method. Changing this process will take considerable education.

How can we deal with the invasive species problem in a humane way? Better minds than mine will need to think about that. But I hope that someone is thinking about that. I certainly want the Chesapeake Bay to become a healthier, more productive ecology in the future, but I hope that can be achieved with less brutality in the future.


Know What an Invasive Species is? July 21, 2011

Filed under: Science — newdomino @ 11:33 AM
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A good portion of my on-the-clock time is spent working on invasive species issues, particularly educating staff and the public on what constitutes an invasive, why they are considered “bad” and how people can help get rid of them.  Staff has taken up the cause with a lot of gusto, or at least with as much effort as they can muster given all the other natural resource management duties that have.  And some portions of the public have jumped right in to pulling invasive plants, monitoring for invasive insects and hunting invasive mammals.  But I still struggle with reaching out to the general public so they know what an invasive species truly is and why they should care about them.

To start from the beginning, let me give you a definition of what an invasive species is; it is a non-native plant, animal or pathogen that causes harm to human health, to the environment or to the economy.  Sometimes an invasive can cause harm to more than one of those segments, too.  Let’s give you some examples:

Garlic mustard grows densely along forest edges. (Photo: Jessica Sprajcar, DCNR)

  • Garlic mustard is a very common invasive plant here in the northeast.  It was brought over by colonists as an herb, it escaped from cultivation and has taken over many a forest edge, backyard and roadside.  The roots release a chemical with allelopathic properties – meaning that the plant alters the soil chemistry to benefit itself and prevent native plants from growing.  If that wasn’t bad enough, the West Virginia white is a butterfly that lays its eggs on native plants related to garlic mustard.  If it lays its eggs on garlic mustard, the eggs cannot hatch.  So garlic mustard is bad for our native plants and insects.




West Nile virus is spread by mosquitos. (Photo: Susan Ellis,

  • West Nile virus is an invasive pathogen spread by mosquitos.  It was first discovered in the U.S. in 1999 and has spread throughout much of the country since then.  Infected people can have mild symptoms like nausea and headaches or potentially fatal symptoms like encephalitis or meningitis.  While most people survive contracting the virus, roughly 10 percent of severe cases pass away, according to the National Institutes of Health.



Zebra mussels growing on a native mussel. (Photo: Randy Westbrooks,


  • Zebra mussels are tiny mollusks that arrived in the Great Lakes in boat ballast water.  These fingernail-sized critters have since spread to rivers in the northeast and beyond, as boaters take their watercraft to new lakes and rivers in the name of recreation.  Zebra mussels, and their kindred – quagga mussels – have caused at least $5 billion (yes, with a “b”) worth of damage to the Great Lakes area between 2000 and 2010, according to the U.S. Geological Survey.  These invasive mussels also kill our native mussels by smothering them and they are such effective filter feeders that they leave little phytoplankton for other bivalves and young fish.




To me, those are all serious impacts to our lives and the health of our environment and seem worthy of some thought.  But I get the sense that still, most people out there have no idea what an invasive species is.  How do I get people to care more about them so that they can identify a few of the more troublesome species and take the effort to try and get rid of them (or at least let an agency like mine know so that we can try to help)? 

I look to you for ideas!


What in the World is an Invasive Species ? October 25, 2010

Today I read a great, quick article on about research that is looking to turn invasive plants into biofuel.  It got me thinking about the whole subject of invasives and wondering whether most people have a good idea of what they are.  I’d be curious to have your feedback – when it comes to invasive species, what do you know?

The federal definition of an invasive species is a species (plant, animal, disease) that isn’t native to the area that causes or is likely to cause harm to human health, to the environment or to the economy. Whether a species is or isn’t native to an area is usually determined by looking at historical records – if it existed before colonists arrived, it’s native. If it arrived since then, it’s non-native or exotic.  Not all non-natives are invasive, though. If you think about many of our fruits and vegetables, they originally came from somewhere else, but they don’t grow out of control and take over forests and meadows. They stay where they’ve been planted.

Invasives, on the other hand, grow like wildfire.  One Japanese barberry shrub can become dozens upon dozens as birds and people spread their seeds. One emerald ash borer can become thousands as people move firewood from state to state.  Invasives are such a concern to me and the rest of the conservation community because they out-compete our native plants for space, and our native animals for food.  They grow so densely that they can block trails and access to stream and river banks.  The cost of trying to rid ourselves of these invaders runs into the billions of dollars each year. 

An invasive shrub - Japanese Barberry

What makes something invasive? Well, typically they reproduce quickly or produce abundant amounts of seed.  Purple loosestrife, for instance, can produce millions of seeds per plant per year!  Many invasive plants can also reproduce vegetatively, meaning that they send out underground rhizomes (root-like) that sprout new plants. Cut down a Tree-of-Heaven and you’ll have dozens of little sproutlets in its place. Invasives can grow pretty quickly too; mile-a-minute vine and kudzu can grow up to a foot a day in some parts of the country!  Plus they usually don’t have any natural enemies trying to feed on them; that puts them at a competitive advantage over our native species.  If you’ve ever seen a streambank covered with Japanese knotweed you’ll notice that there are very few insect chew holes on the leaves. Japanese beetles (you guessed it – another invasive!) are one of the few insects in the U.S. that will bother trying to eat it!
What does all this mean for the average Pennsylvanian? Well, no matter whether you own a piece of land or not, you can do something about invasive species.  It boils down to planting species that we know are not invasive.  The easiest way to do that is choose natives.  The second easiest way is to look at and make sure the plants you’re planning on buying aren’t on their lists.  Many nurseries and big box retailers still sell plants that are considered invasive in some parts of the country. Know what to look for and avoid.  If you have pets, especially the reptile and amphibian kind, do not release them into the wild.  More likely than not they’ll die, but a few may survive and become and invasive nuisance. Pythons are doing it in Florida; red-eared slider turtles are doing it here in Pa. 

An invasive tree - Norway Maple

Don’t move firewood from place to place. This is one major way invasive insects travel from state to state, wreaking havoc to trees along the way.  If you’re out hiking or mountain biking, brush of your boots and tires before going somewhere else. Otherwise invasive seeds can hitch-hike on your gear.  Cleaning of boats and fishing tackle is also important to cut down on the spread of aquatic invasives like zebra mussels, rock snot and hydrilla.
Some people ask why we bother with invasives.  Some are well-established, they cost a lot of money to control, and after all – aren’t human beings the ultimate invasive species? Well, yes I guess we could be considered an invasive. I’m sure the countless extinct plants and animals would call us that if they could.  But because we have the ability to think and act it, shouldn’t we try?  Yes, invasive species control can cost a lot of money but the cost of inaction is far greater.  The economic damage to our crops, timber industry and health from invasives is much higher than the control costs.  And yes, some invasive species are pretty common by now, since for decades they were allowed to spread uncontrolled, but now that we know their negative impacts, if we can act, why not try? 
Want to learn more about invasive plants? I highly recommend:  For invasive animals (including insects) and pathogens (plus additional info on plants), check out