Analysis revealed instances where native trees were actually poorer foraging resources for songbirds than certain species of invasive shrubs
As have several studies before, a recent study from New England has shown that the categories “invasive” and “native” don’t predict if a species will be better or worse at supporting bugs and birds.
The authors pointed out that:
Clearly some invasives are worse than others and it’s not as simple as all invasive plants must go. While we certainly do not suggest that invasive plants have no negative ecological impacts, our study shows that coexisting native plants are not always superior resources for wildlife and that context is important.
Managers need to know whether the native plants that are most likely to replace removed invasives are really of greater value to the wildlife for which they are managing the habitat, and if that effort is worth the cost and disturbance.
From an article summarizing the study
Unexpectedly, all lines of evidence in the study suggested the invasive plants were comparable to the natives in their value as foraging resources for birds. Arthropod biomass and protein content were broadly similar between the native and non-native species, and in turn, the birds foraged just as intensively on the non-native plants as they did on the natives.
The differences between species were far greater than between the groups “native” and “invasive.” Invasive honeysuckle was one of the highest value plants in the study, for example, even compared to natives, while barberry was well below most others. So before removing an invasive, or a native for that matter, it’s best to find out if you can how beneficial that particular species is, and to weight the costs of the removal and disturbance.
Around here, that description fits chinaberry (fruits ripen in late winter/early spring when nothing else is ripe) and privets. Glossy privet has a similar ripening window to chinaberry, Chinese privet is in summer but strongly preferred by birds. I’ve seen birds avoiding ripe viburnum and going straight for privet.
There are surely others, but those ones come to mind.
in SE Alaska (especially in my experience) & elsewhere I’ve noted thatpickup trucks (which often have bags of trash in the back or open back windows leading to junk food) are a much more preferred non-native tree to Ravens than, say, cottonwoods or birches (excspt for sitting and crowing in).
So just because it is not a native plant does not mean birds will not eat and spread it. All invasive means to me is it spreads easily. Porcelain Berry is considered an invasive because the birds spread them everywhere. I think I read at one point in Latin America and the Caribbean the pepper is invasive due to birds eating them and in those countries the peppers never die to cold. Birds don’t taste the chemical in peppers so to them it has no heat. Peppers have coevolved with a relationship with birds to be spread farther distances. Here in CO thistle and dandelion grow super well and is native but neither is not a plant most people want. The reason you may want a native is how well they grow. There is some non native that grow super well where I live like apples but they are the exception. Things that grow native here like the flocks, geranium etc. will grow without fuss, little to no watering or sprays. Clearly if they can be found in the wild in state parks they can be easily grown in a garden.
That is surprising. The only native plants we have found challenging are the ones that are just unnatural to grow in a confined area. Aspen is an example of a plant here that many want to grow because it is a pretty native but is not suited to a yard. It is suited to an area that it can spread a thicket for miles or acres at least. Many try to cultivate them but fail. My best bet for those who enjoy aspen is to get the bronze or gold plates leaves or artwork with them and drive up to the state parks.
I think Autumn Olive was introduced for forage. It feeds deer, bears, turkeys, skunks, possums, squirrels as well as grouse and pheasants and all kinds of birds.
It is a favorite for bees bumbles and honeybees… i think some folks even make autumn olive honey.
Its invasive…and a non-native and i think they label it as a noxious weed on paper i think… but its been here for 200 years… and on top of everything else it helps erosion and is a nitrogen fixer.
To me it basically seems to thrive here on hillsides and places where humans have clearcut or stripped areas of all life.
I imagine its a safe habitat and ecosystem for mice and snakes and rabbits and likely all kinds of things.
Most folks hate it and want it gone… it gets sprayed… but i think its here to stay and seems to benefit everything except humans thought processes.
I’m so saddened when folks use chemical stump treatment to remove autumn olive. Such a blessing to the land. The answer is more shade and less disturbance! They don’t thrive in forest canopy
You raise a good point. Very few invasive plants actually invade undisturbed habit. Old forests, most swamps, and typically meadows, prairie and rangeland that get proper grazing pressure, are not where you usually find invasive species. It’s in forestry plantations, mowed grass, field margins, old homesites, and of course, suburban and urban lots, where you find the most invasive species. There are exceptions, of course, but that is the general pattern.
One wonders if it’s actually the disturbed and altered habitat that’s more the problem than the plants that filled in the void…
This is at an industrial park. Loaded with life of all kinds. There are lots of blackberries, raspberries and i think grapes. Autumn olive is thriving. No reason for anyone to mow it. I see birds going in and out probably nesting. I would rather see these invasives than a nicely mowed area myself.
I know certain plant seeds things like fires or being shredded up help them germinate. It could be those reasons. Or it could be confirmation bias. We spend more time is an urbanized setting and often times when we go to a non urbanized setting we are going to a state or federal park. For this reason we are more likely to notice the weed in the lawn vs the weed out in the middle of nowhere.
It can be a self-perpetuating cycle. Here in California, most of our ecosystems are fire adapted, but average fire frequency ranges from a few decades in chaparral to centuries in conifer forests. If fires occur too close in succession, the plants won’t have had time to reach maturity and are killed before they can reproduce. Invasive Old World grasses, most of which are annuals and can build a lot of biomass in a single wet season unlike our native perennial bunchgrasses, seed themselves into chaparral following a fire, prevent natives from reestablishing, and then encourage more fires at a higher frequency. Now much of our landscape dries out and goes brown by late May, whereas before the introduction of grazing livestock and nonnative grasses, bunchgrasses and shrubs, with their much deeper root systems, could stay green well into summer.
My impression is that it is a lot easier for invasives to disrupt an ecosystem in seasonally arid climates. Those places are just inherently more fragile and even a little bit of disturbance can spiral into a big mess.
Here in the South? It takes a dedicated effort to keep the wilds at bay. After just a two years with less regular mowing (roughly semi-annual), my backyard is full of pine, sweetgum, privet, boxelder, callery pear, various oaks, and honeysuckle seedlings, and a good half dozen different kinds of tallgrass. I’ve been debating which parts of the yard to start mowing more often and which parts to let go wild, but looks like this is the last year I have to decide because I’m already at the limits of what my mower can cut.
I use a mower like this Billy Goat 26 In. Brush Cutter BC2600-ICM - Acme Tools to keep areas of my forested land in an early succession stage. I also use it annually on my acre of wild flowers to keep brush/trees from ever getting much of a start. The mower is a beast. It easily cuts saplings 1.5" thick and can take softer wood saplings like box elder up to 2"+
That depends. Colorado is arid but it is a tough growing environment due to our seasons and lack of water. Without constant water our lawns here are brown by early to mid July. It was luckily made illegal to have HOA require grass here in recent years because there is no way to keep it green like a HOA would want and lawns are just too water intensive here. Can it be done sure it can but it is insanely wasteful. My mother loves to talk about seeing snakes easier on the lawn but she sure failed to see a huge rattlesnake on someone else’s brown lawn.
Garlic mustard supports birds, thank-you-very-much. They eat the seeds, and I am sure they spread it by “caching” it (that is, burying it in the ground with the idea they will eat it later, but they sometimes never get around to it).
No one appears to be blaming birds for its spread, but I am told the main ingredient in commercial “bird seed” for stocking bird feeders is the domesticated mustard seed cousin to garlic mustard.
The stock explanation is the deer and other forest creatures track seeds out on their hooves and paws, but the way a stand of garlic mustard just pops up in the middle of nowhere suggests to me an airborne invasion.
So this exotic-invasive keeps birds happy, but its dense stands and way of poisoning-out native plants wipes out everything on the forest floor apart from garlic mustard.
