some type of adult girl

the-awkward-turt:

pleasespellchimerical:

Ok but can we talk about non-native and invasive species in a nuanced way?

There’s more to this topic than ‘native = good’ and ‘non-native = invasive and therefore bad’. I also see horrible analogies with human immigration, which…no. Just no. 

Let’s sit back and learn about species and how they work inside and outside their native ranges! Presented by: someone who studied ecology.

Broadly speaking, when talking about species in an ecosystem, we can divide them into four categories: native non-invasive, non-native, non-native invasive, and native invasive.

Because ‘native’ and ‘invasive’ are two different things. 

Native and non-native refers to the natural range of a species: where it is found without human intervention. Is it there on its own, or did it arrive in a place because of human activity?

Non-invasive and invasive refers to how it interacts with its ecosystem. A non-invasive species slots in nicely. It has its niche, it is able to survive and thrive, and its presence does not threaten the ecosystem as a whole. An invasive species, on the other hand, survives, thrives, and threatens the balance of an ecosystem. 

Let’s have some examples! (mostly featuring North America, because that’s the region I’m most familiar with)

Native Non-invasive

Native bees! Bee species (may be social or solitary) that pollinate plants.

And stopping here bc I think we get the point.

Non-native

Common Dandelion: Introduced from Europe. Considered an agricultural weed, but does no harm to the North American ecosystem. Used as a food source by many insects and animals. Is prolific, but does not force other species out.

European Honeybee: Introduced from Eurasia. Massively important insect for agricultural pollination. Can compete with native pollinators but does not usually out compete them.

Non-native Invasive

Emerald Ash Borer: Beetle introduced from Asia. In places where it is non-native, it is incredibly destructive to ash trees (in its native range, predators and resistant trees keep it in check). It threatens North America’s entire ash population.

Hydrilla: An Old World aquatic plant introduced to North America. Aggressively displaces native plant species, and can interfere with fish spawning areas and bird feeding areas. 

Native Invasive

White Tailed Deer: Local extinction of the deer’s predators caused a massive population boom. Overgrazing by large deer populations has significantly changed the landscape, preventing forests from maturing and altering the species composition of an area. Regulated hunting keeps deer populations managed.

Sea Urchins: The fur trade nearly wiped out the sea otters that eat them. Without sea otters to keep urchin populations in check, sea urchins overgrazed on kelp forests, leading to the destruction and loss of kelp and habitat. Sea otter conservation has helped control urchin populations, and keeps the kelp forest habitat healthy.

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There are a few common threads here:

The first is that human activities wind up causing most ecosystem damage. We introduce species. We disrupt food chains. We try to force human moral values onto ecosystems and species. And when we make a mistake, it’s up to us to mitigate or reverse the damage.

The second is that human moral values really cannot be applied to ecosystems. There are no ‘good’ or ‘bad’ species. Every species has its place. Applying emotional and moral rhetoric to ecology works against our understanding of how our ecosystems work. 

Third: the topic of invasive and non-native species is more complex than most of the dialogue surrounding it. Let’s elevate our discussions.

Fourth: If you ever compare immigrants or minorities to invasive species, I will end you.

There are more nuances to this topic than I presented as well! This is not meant to be a deep dive, but a primer.

THANK YOU

I’ve been thinking of making a post like this because people using “invasive” and “non native” interchangeably drives me up the wall, but you did it so much better!

I remember one of my ecology professors saying that only something like 1 in 10 nonnative species introduced to a new habitat will be able to establish there, and only 1 in 10 of those will be damaging to the ecosystem. The majority of nonnative species aren’t invasive, we just hear a lot about the really bad ones.