So, following up on the little bit of stink kicked up by this post, I thought I’d do a little work to try and explain the concept behind murdering innocent animals for non-food purposes. Or killing plants, insects, trying futilely to stop fungi, or otherwise attempting to control whatever biological specimen it is that’s somewhere it possibly shouldn’t be due to human interference.
First off, I feel I might say if any of you read Sole Eater’s words and were turned off, that’s (to me) understandable (though you may disagree with SE’s words for a different reason than I may). I have mixed feelings about the act of killing “ferals”, what bothered me more was the tone and kind of self-indulgent attitude of SE speaking of the satisfaction of killing from far away, etc., with the feral aspect being what seems to me simply an excuse for doing what Sole Eater wants. Which possibly he (I think he is correct in this case) may feel is incorrect or is perfectly justified, but that’s not the point, really.
What I’d like to address is the reality of introduced, invasive species.
There is no place on the planet that does not have some human-induced change, even if it is atmospheric. But potentially just as damaging to natural systems are introduced species, those that have been brought into a “stable” ecosystem by humans. “Stable” being a little misleading, as all natural systems are dynamic, though they generally seek equilibrium, and usually achieve some semblance of that. An old-growth forest, for example, tends to grow stable over time, with occasional disturbances changing composition in patches (but occasionally vast swaths). Plant, animal, fungal, invertebrate and microbial species in within an ecosystem work in a complex interconnectedness that has very slowly changed with evolution. Every ecotype has developed over the ages, and change occurs very slowly, usually. Bringing a non-endemic species into an ecosystem can occasionally wreak havoc within that system by introducing an uncontrolled element into a niche. As an example, we can talk about something very familiar to me, hemlock forests. Hemlocks
(Tsuga spp.) exist in many temperate forests in North America and Asia. In the Asian and western North American populations, a small aphid-like insect has co-evolved with the native hemlocks as a minor pest. This insect, the hemlock woolly adelgid, was accidentally brought into the United States in the twenties. It has slowly spread throughout the range of eastern hemlock (Tsuga canadensis) and also reaching the south where it has infested the Carolina hemlock (Tsuga caroliniana). These hemlock species did not evolve with the adelgid, and therefore have no resistance at all to them (it’s thought that specific terpene compounds in the resistant hemlocks are what protect them). Other than cold weather in the north reducing populations, there is nothing that stops the adelgid from killing all hemlocks.
Hemlocks are a unique component of many forests, and hemlock dominated forests are a unique ecosystem here. They are possibly the most shade tolerant tree species on this continent, and can grow to be at least 550 years old (and almost certainly older). They change the ph of water that percolates through their litter and hold on to nitrates much longer than other species. They are the only evergreen tree that populates streambanks, and through their evergreen shade they cool the water temperature; streams with large numbers of hemlocks are cooler and more nutrient-poor than other streams, a specific stream type that many other species are adapted to.
Anyway. I don’t need to go on with all of the dynamics of hemlock forests and the other species that exist and/or depend on them, let’s just say that they are a vital component in certain forests, and that they are currently dying out throughout the southern half of their range, except for isolated trees or stands that are chemically treated. This will vastly change the landscape of the forests, and there is no other species that can fill hemlocks’ niche. Hundreds of thousands of trees will die, including many of the last remaining old-growth hemlock forests. This is very similar (though smaller scale) to the impact when the introduced fungus Cryphonectria parasitica killed every mature chestnut tree in the country in the early 20th century.
So, there is a large impact from the introduction of a small insect or fungus on an imported plant, but these are only two stories in a worldwide crisis. It’s been going on for a long time- many of the first ships that traveled the trade routes hopping from island to island introduced rats, dogs, pigs, mosquitoes, and diseases. Many smaller islands had endemic species wiped out by introduced species.
In the U.K., many native plants and heathlands are being eliminated by introduced Rhododendron ponticum (well, ponticum hybridized with other rhodos), the New Zealand flatworm is eating native earthworms and degrading soil quality, bullfrogs are pushing out native amphibians, and minks are killing water voles, among other problems ( I realize the fact that the language used discussing these topics unfortunately overlaps with anti-immigrant language, which can be off-putting).
Australia has problems with the mammals water buffalo, rabbit, goat, rats, cats, etc. It also has an American introduction, pond-apple, which is taking over Melaleuca swamps. Meanwhile, in Florida, Melaleuca is taking over swamps with pond-apple. This is just scratching the surface.
Nearly every part of the world has some problem like this. So, the argument is, I suppose, is it good or right to try to eliminate these things, in order to try and either maintain some natural equilibrium or to restore it? People may not balk at the idea of spraying a tree with an insecticide or fungicide to kill a small insect or fungus that threatens the tree. Maybe they don’t feel too bad about cutting rhododendron or spraying herbicide on broom sedge to try and keep them from taking over utterly. The idea of blasting a water buffalo to try and help out the natural ecosystem is pretty distasteful, but before the Australian government earnestly started an eradication program the water buffalo population was up around 350,000 and they were totally destroying wetlands and annihilating native species. What should be done in that case? Personally I am pretty much for eliminating these species, especially in cases where the impact is greater and the viability for restoration is there. I don't like killing things, it's one of those "greater good" equations that isn't easily quantifiable. Eliminating Japanese stilt grass from around here is pretty much impossible, unless someone finds a viable biological control. Biological controls are the ideal, provided they only affect the target species.
I'd like to hear if anyone else has any kind of opinion or thoughts on this, rather than run through every possible argument for or against control. |
