Immigrant species are generally neutral to beneficial; the whole concept of "invasive species" is mostly fallacious (at least when they're vertebrates on continents)
The book sounds like one to add to my library. I dislike the name "invasive," it has negative connotations. Something more neutral should be found. Each continent and region of each continent has different meterological, hydrological, microbial, soil properties and different species will do well there or not. Nature sorts out things with species spread on its own. It doesn't need much help from us. Nature is a bit like a scientist:. Each new species is n experimental hypothesis being tested. We ourselves are such, but we shouldn't put ourselves primus inter pares. The experiments are very long term and who knows if we will succeed or not.
Sam, with all due respect I'd recommend that you continue your studies in this area, because this topic is too important to leave your audience with an incomplete impression. If 'invasive' is too pejorative a term, I've heard 'aggressive alien' species used to convey the idea.
Regardless, I'd recommend the work of Dr. Douglas Tallamy to help you understand further. He's an entomologist, which is key to his major insight that native plants are in fact vital to local food webs, because they are what the local insect populations have evolved to eat (& thereby serve as the energy transfer link from plants to animals) - think caterpillars, and think all the birds who rely on caterpillars as their major protein source for breeding and raising their young. It is a fact that many invasive plants are simply inedible by local insect populations, because they have not evolved the capability to digest them. When this happens at scale, the energy transfer from plants to animals is reduced. Less energy coming through the food web, less diversity of life.
When you start to get a sense of the interconnected picture of the food web, you realize it's not enough to see some plants doing well, or serving a slice of the pollinator population (as with your honeysuckle example).
Lastly, I'd invite you to take a walk through an oak / hickory forest, for example, here in southwest Michigan, in which honeysuckle and autumn olive have become established in the understory. It may look like they are supporting pollinators and birds - in fact autumn olive was distributed for planting 40 years ago because bird lovers back then thought (incorrectly as it turns out) those shrubs would support migrating bird populations. What is happening is that these invasives (yes, in this context they deserve the label) are so successful in the understory (because guess what, the insects and deer leave them alone so they outcompete natives!) that there is a scarcity of younger oaks and hickories coming up to succeed the overstory trees.
If you want Americans to embrace your view, based on my observations of Americans in Australia you have a simple solution. Release some Koalas into the wild in California stat. You already have the Blue Gums
Thanks for highlighting this. I've personally never been able to get on board with the local community weed cleanup campaigns because it always seemed hypocritical. You see I'm a white person flourishing in Australia, an invasive species by many an account. When you include human species in this argument things get really interesting.
Hi Sam, thanks for a thoughtful piece. Here's a reaction: "native" versus "invasive" is not the appropriate dichotomy. Most non-native plants are not invasive. According to the brilliant work of Dr. Doug Tallamy (who would have erudite things to say about this piece) about 10% of non-native plants in eastern US suburban settings are invasive, meaning they displace native plants. And this is key: native plants and insects have co-evolved; native insects need native plants as host plants, which are essential to their reproductive cycle. For example, Monarchs required Milkweed species to feed their caterpillars. The non-native black swallow-wort plant has been introduced to the US east. It is close enough to Milkweed (same Family) to fool Monarchs to lay their eggs on it, but the caterpillars cannot eat it and die. So the host plant concept is crucial to the analysis of native plant and insect ecology.
I absolutely agree with you that native versus invasive is an inappropriate dichotomy, and I'm trying to promote judging and managing species based on their specific impacts on the ecosystem, not their origins. For example, monarch conservation right now would logically support the non-native eucalyptus tree but not the non-native black swallow-wort, as you point out!
I'm really enjoying all of these "Immigrant Species Biology" articles. You should research Kachana Station in the Kimberley, Western Australia. The donkeys and goats have ravaged the kimberley, but they're using them in a semi-managed sense to restore the land across an enormous station... and it's really seeing results. They talk of the need for more "land doctors" who look at the ecosystem as is (native/invasive) and work within it, part of it. The RegenNarration podcast does some great episodes on Kachana.
Oh the key thing about this is what they're doing is illegal, as they're obliged to shoot all donkeys on the station. So they're currently fighting legal battles here while also clearly demonstrating successful land regeneration amidst an intensely desertifying landscape...
So much to think about here, Sam! And a lot of new information I wasn’t aware of. I had no clue about these efforts to wipe out hybrids. Killing in the name of…! I’m definitely going to check out that book. As I said in a previous comment, each invasive species should be weighed on its own merits or demerits and not any kind of sweeping generalization, which can easily reflect prejudices.
One thing I’ve never understood on the metaphorical level: it seems like the best analogy to invasive species attitudes is anti-colonial politics, not “blood and soil” politics. But I guess at the base of any anti-colonial movement is a base of identity or nationalism for the colonized area. For instance, how can you have Scottish independence without it bleeding in to xenophobic nativism? Maybe two sides of the same coin.
But that’s only an analogy for what’s going on with species being moved around by humans. Best to just focus on the facts.
Oh, I was also going to say that the resilience of nature is amazing and even surprising. We can only hope that the planet can adapt to the many changes we’re making faster than we expected.
I think however, when humans develop land, or harvest natural resources, we should “leave it how you found it.” That is to restore a certain percentage of the current “native” population to prevent overwhelming the prevailing critical functions of the food web. Imposing a blanket of lawns and cultivated plants upon human settlements can deplete critical natural resilience to the ever changing climate resulting in droughts, flooding, and increased temperatures (the urban island effect).
Reintroducing keystone plants and creatures has been successful in reversing these effects and should be adapted to the development process which would insure its widespread adoption. This is preferable to retroactively garnering enough support to fix it after it’s broken.
I would ask Chris Thomas to consider the implications of Pinus radiata colonising huge swathes of the New Zealand landscape before giving such glowing forecasts. The pine monoculture that typifies our commercial forestry doesn't just rely on this one species -- millions of the trees planted are clones. What happens when (not if) a pest or disease reaches these shores and finds a banquet table spread out waiting is not a matter of guesswork.
Pines' coevolution with fire is another hugely problematic aspect of planting them alongside an ecosystem that has evolved in a nearly complete absence of burning. As our climate warms and becomes more prone to drought, commercial timber stands are puddles of petrol awaiting a match. Wildfire that spreads into intact or regenerating native bush is catastrophic and we've got our own endangered species to worry about without getting all weepy about Californian pine trees (and I have a soft spot for the Monterey Bay, having spent memorably holidays there as a child and young adult).
For another example of an iconic landscape that is being modified and most likely terminated by an invasive exotic, read up on the Sonoran Desert and buffelgrass.
The book sounds like one to add to my library. I dislike the name "invasive," it has negative connotations. Something more neutral should be found. Each continent and region of each continent has different meterological, hydrological, microbial, soil properties and different species will do well there or not. Nature sorts out things with species spread on its own. It doesn't need much help from us. Nature is a bit like a scientist:. Each new species is n experimental hypothesis being tested. We ourselves are such, but we shouldn't put ourselves primus inter pares. The experiments are very long term and who knows if we will succeed or not.
Sam, with all due respect I'd recommend that you continue your studies in this area, because this topic is too important to leave your audience with an incomplete impression. If 'invasive' is too pejorative a term, I've heard 'aggressive alien' species used to convey the idea.
Regardless, I'd recommend the work of Dr. Douglas Tallamy to help you understand further. He's an entomologist, which is key to his major insight that native plants are in fact vital to local food webs, because they are what the local insect populations have evolved to eat (& thereby serve as the energy transfer link from plants to animals) - think caterpillars, and think all the birds who rely on caterpillars as their major protein source for breeding and raising their young. It is a fact that many invasive plants are simply inedible by local insect populations, because they have not evolved the capability to digest them. When this happens at scale, the energy transfer from plants to animals is reduced. Less energy coming through the food web, less diversity of life.
When you start to get a sense of the interconnected picture of the food web, you realize it's not enough to see some plants doing well, or serving a slice of the pollinator population (as with your honeysuckle example).
Lastly, I'd invite you to take a walk through an oak / hickory forest, for example, here in southwest Michigan, in which honeysuckle and autumn olive have become established in the understory. It may look like they are supporting pollinators and birds - in fact autumn olive was distributed for planting 40 years ago because bird lovers back then thought (incorrectly as it turns out) those shrubs would support migrating bird populations. What is happening is that these invasives (yes, in this context they deserve the label) are so successful in the understory (because guess what, the insects and deer leave them alone so they outcompete natives!) that there is a scarcity of younger oaks and hickories coming up to succeed the overstory trees.
If you're interested, here's a link to a talk by Dr. Tallamy from earlier this year: https://youtu.be/9_FlSBwUr_s?si=2y1b7UJmEy5z10q3
Thanks for your work, Sam, and keep it going!
If you want Americans to embrace your view, based on my observations of Americans in Australia you have a simple solution. Release some Koalas into the wild in California stat. You already have the Blue Gums
Thanks for highlighting this. I've personally never been able to get on board with the local community weed cleanup campaigns because it always seemed hypocritical. You see I'm a white person flourishing in Australia, an invasive species by many an account. When you include human species in this argument things get really interesting.
Always thank you for intelligent and thoughtful articles…and inspiring ideas !
Thank you so much !
Hi Sam, thanks for a thoughtful piece. Here's a reaction: "native" versus "invasive" is not the appropriate dichotomy. Most non-native plants are not invasive. According to the brilliant work of Dr. Doug Tallamy (who would have erudite things to say about this piece) about 10% of non-native plants in eastern US suburban settings are invasive, meaning they displace native plants. And this is key: native plants and insects have co-evolved; native insects need native plants as host plants, which are essential to their reproductive cycle. For example, Monarchs required Milkweed species to feed their caterpillars. The non-native black swallow-wort plant has been introduced to the US east. It is close enough to Milkweed (same Family) to fool Monarchs to lay their eggs on it, but the caterpillars cannot eat it and die. So the host plant concept is crucial to the analysis of native plant and insect ecology.
I absolutely agree with you that native versus invasive is an inappropriate dichotomy, and I'm trying to promote judging and managing species based on their specific impacts on the ecosystem, not their origins. For example, monarch conservation right now would logically support the non-native eucalyptus tree but not the non-native black swallow-wort, as you point out!
I'm really enjoying all of these "Immigrant Species Biology" articles. You should research Kachana Station in the Kimberley, Western Australia. The donkeys and goats have ravaged the kimberley, but they're using them in a semi-managed sense to restore the land across an enormous station... and it's really seeing results. They talk of the need for more "land doctors" who look at the ecosystem as is (native/invasive) and work within it, part of it. The RegenNarration podcast does some great episodes on Kachana.
Sounds awesome!!
Oh the key thing about this is what they're doing is illegal, as they're obliged to shoot all donkeys on the station. So they're currently fighting legal battles here while also clearly demonstrating successful land regeneration amidst an intensely desertifying landscape...
*Extremely* awesome.
So much to think about here, Sam! And a lot of new information I wasn’t aware of. I had no clue about these efforts to wipe out hybrids. Killing in the name of…! I’m definitely going to check out that book. As I said in a previous comment, each invasive species should be weighed on its own merits or demerits and not any kind of sweeping generalization, which can easily reflect prejudices.
One thing I’ve never understood on the metaphorical level: it seems like the best analogy to invasive species attitudes is anti-colonial politics, not “blood and soil” politics. But I guess at the base of any anti-colonial movement is a base of identity or nationalism for the colonized area. For instance, how can you have Scottish independence without it bleeding in to xenophobic nativism? Maybe two sides of the same coin.
But that’s only an analogy for what’s going on with species being moved around by humans. Best to just focus on the facts.
Absolutely, I think we should focus on the facts. I think you'll really enjoy the book; one of my favorites!
Oh, I was also going to say that the resilience of nature is amazing and even surprising. We can only hope that the planet can adapt to the many changes we’re making faster than we expected.
I agree 100%!
I think however, when humans develop land, or harvest natural resources, we should “leave it how you found it.” That is to restore a certain percentage of the current “native” population to prevent overwhelming the prevailing critical functions of the food web. Imposing a blanket of lawns and cultivated plants upon human settlements can deplete critical natural resilience to the ever changing climate resulting in droughts, flooding, and increased temperatures (the urban island effect).
Reintroducing keystone plants and creatures has been successful in reversing these effects and should be adapted to the development process which would insure its widespread adoption. This is preferable to retroactively garnering enough support to fix it after it’s broken.
I would ask Chris Thomas to consider the implications of Pinus radiata colonising huge swathes of the New Zealand landscape before giving such glowing forecasts. The pine monoculture that typifies our commercial forestry doesn't just rely on this one species -- millions of the trees planted are clones. What happens when (not if) a pest or disease reaches these shores and finds a banquet table spread out waiting is not a matter of guesswork.
Pines' coevolution with fire is another hugely problematic aspect of planting them alongside an ecosystem that has evolved in a nearly complete absence of burning. As our climate warms and becomes more prone to drought, commercial timber stands are puddles of petrol awaiting a match. Wildfire that spreads into intact or regenerating native bush is catastrophic and we've got our own endangered species to worry about without getting all weepy about Californian pine trees (and I have a soft spot for the Monterey Bay, having spent memorably holidays there as a child and young adult).
For another example of an iconic landscape that is being modified and most likely terminated by an invasive exotic, read up on the Sonoran Desert and buffelgrass.
100% Phil! Unfortunately the post overlooks a lot of the effects. The increased wildfire risks of wilding pines in NZ is very real.
Shall we then celebrate pythons in the Everglades? Lionfish in the Caribbean?