When does non-native become native?

PolePole and I where discussing this on the way back from Mendo. Is there any well established measure for when a non-native species becomes native? I was thinking about stripers on the west coast for example. I mean if they are still here 1000 years from now will they still be non-native?

That's a good question..  and the short answer is never.

First let's start with non-native species concept.  In general non-native implies that humankind (either through a direct method liking stocking or through an indirect method like opening a new canal or accidentally moving species by ships) moved a species from it's native range (where it evolved) to a new area (where it didn't evolve).  It is this intervention by mankind that gives a species its non-native status. 

Sometimes species extend their range all on their own either by accident or because they've adapted to new habitats.  This is how new islands that are formed in the middle of the ocean are slowly populated.  Species that move about in this manner without the aid of man wouldn't be considered non-native and we would refer to them as simply having had a range extension.

Once introduced to a new area by humans, a non-native species may become established or naturalized.  This basically means that like the stripers on the West Coast they are able to maintain a sizeable population without additional stockings.  However, no matter how long the striped bass remain on the West Coast they will remain non-native as long as someone remembers that we brought them here.

Brian

   

So when do you start managing them as a fishery?  When do you start going to extra lengths to protect and preserve them?

-Allen

Probably the best examples are striped bass and largemouth bass in the delta.  Up to a few years ago, strippers were very heavily managed and stocked, even though they are non-native.  This issues lies with the directives of the overseeing agency.  For example California Fish and Games goal is to promote sport fishing.  The practice of conservation biology have swayed these goals to include protection of native species, however CDFG is still responsible for game fish.  So they kind of have mutually exclusive goals, because the protection of native fish usually does not do good things for non-native fish.  For example, the Bay-Delta Vision plan is to restore native fish in the delta by allowing brackish water back into the delta, while this will severely impact largemouth bass. Also the stocking of strippers in the delta stopped in 2002, due to this new emphasis on native species.  The management of non-native game fish in natural habitats is by large on the way out....that is non-native are on there own...for now.  My personal view is that non-native fish should not have been introduced into natural waters in the first place 50 years ago, but we are stuck with them.  In man made reservoirs etc, we should manage for non-native game fish.  To answer your question.  There really isn't a hard fast rule for when to manage a non-native species/naturalized species.  There's a lot of politics involved in the management of native and non-natives....which means organized groups like Coastside can have some influence. 

Jim

Aren't humans part of the eco system? I mean if a striper hitches a ride on a duck or a boat the outcome is the same? Look at fire ants, no one said,"Gee wouldn't it be great if we had these ants that sting like fire!!" They hitched over in fruit crates or other shipments but they could have easily hitched over on some migratory birds. In fact I don't think anyone knows for sure.

These are the same mechanisms animals use to get to those new islands. We are we penalizing humans as un-natural?

For some reason, I really like this discussion.  Carry on.

So what about hatchery salmon and steelhead that have come from another watershed?  Meaning from a different ESU (Evolutionary Significant Unit).  Do they belong or not?  Do they do more good?  Or do they damage the wild salmon and steelhead in that river.

-Allen

strippers were very heavily managed

Sounds like a dream job!

Aren't humans part of the eco system? I mean if a striper hitches a ride on a duck or a boat the outcome is the same? Look at fire ants, no one said,"Gee wouldn't it be great if we had these ants that sting like fire!!" They hitched over in fruit crates or other shipments but they could have easily hitched over on some migratory birds. In fact I don't think anyone knows for sure.

These are the same mechanisms animals use to get to those new islands. We are we penalizing humans as un-natural?

The same could be said about a lot of things that man makes or does.  What is natural?  If man is part of nature and man makes plastics, aren't plastics natural?  If man as part of nature paves over some wet lands to build a mall, isn't that mall just as natural as the wetland?  Shouldn't artificial flavors really be natural flavors becuase man made them and man is part of nature?

Overall, the rate at which species are becoming introduced outside of their native regions is increasing and we can attribute that increase to humans and globalization.  Sure a few species might get spread by a migratory bird here and there, but that background level of "natural introduction" is swamped by the anthropogenic signal.

The only thing certain about the environment is change, the species that are here now were not here 20k years ago, and in the next few thousand years there will be another ice age and all our trout, bass and short-peckered newts will have to move to Mexico or die under a glacier.

At some point the striped bass here will evolve to be genetically distinct from the east coast population, based on the anal genetic sub-division of salmon by stream, tributary, and mothers maiden name, west coast stripers could probably be called a separate subspecies right now.  Someday folks will be faced with having a distinct species that is NOT 'native' but is threatened with extinction.  What to do?  They evolved to live here just like the other fish did after the last glaciers retreated...  The only difference is the trout hitched a ride on a bird and the stripers hitched a ride on a train and got a late start.

Species come and go regularly with or without our help, and in the future it will be impossible to distinguish 'natural' evolution and migration from human influenced events because we have a hand in everything.  Ever fish that ends up somewhere new we're the first suspect, not the duck.  In 10,000 years there will be absolutely no native species left because they'll all have evolved into something new, living someplace new, under significant human influence.

As ecosystems change, species migrate and are introduced, and the climate changes.  What is 'native' will blur into meaninglessness and attemps to 'restore' habitat to the way it was will be as impossible as trying to 'restore' california to it's pleistocene flora/fauna.  Someday folks will have to realize that attempting to maintain an ecosystem at some arbitrary baseline is a rediculous concept.  What then to replace it?  How about maximizing sustainable productivity?  That's easilly measured (compared to 'native biodiversity'), non-arbitrary, and actually makes the world a better place for everyone - including the plants and animals that are appreciated more.

Any biologist worth their salt will acknowledge that change and environmental/evolutionary pressure is always present.  What the key difference is that in an evolutionary blink of an eye, changes in the environment are occurring at astonishing rates, and that every few years new environmental pressures (invasive species, changes in water pH, inorganic chemicals, Etc) emerge.  We are constantly reshuffling the deck with new changes and pressures, without clear knowledge of the outcomes. 

Its the speed of the changes that are frightening and potentially damaging to any fishery.   

Do you think the cane toad could be considered native to Australia? Or maybe most of the grasses in the United States, which came as a result of the feed for horses brought by our fore fathers on those kick butt wooden boats over 250 years ago? This is a very good question and and I love the dialog.

It's almost like the berthing question; is a c-section a natural berth? 

Mahi mahi , your correct the golden hills of California, that the state is famous for is a result of introduction of feed grasses for cattle.  Historically most the state stayed pretty green throughout the year.  I think if we could go back 150 years and see native California, we would sh*t ourselves.  During wet winters the entire central valley from Marysville to just about the grapevine would be underwater.  There's an interesting book out called "The Inland Sea of California".  It chronicles all the changes that occurred with the settlement of California by whitey.  As a scientist myself, I go back and forth about the native-nonnative issue.  We have lots of things that have been introduced and naturalized that don't cause major havoc, but there are some introductions that have had devastating effects.  Most of which have been on oceanic islands where native animals are naive to introduced predators.  Because of the concern for an introduction to cause environmental damage...aka economic damage we have policies to fight the spread of non-natives.  One of a concern now in California is the zebra mussel or quagga mussle which just showed up in Arizona.  This bugger has had devastating effects in the Great Lakes.  And in SF Bay we have had the Corbula clam that can filter the water column faster than the tide can change, and we no longer have algae blooms in the spring.  This bugger is one of the culprits in the Pelagic Organism Decline in the upper estuary-delta.  So in non-natives are rarely a good thing, more likely benign, but what if pike get into the delta and eat all the salmon.  That would suck in my professional opinion. 

Jim

Salmon manage to survive in the great lakes and on the east coast dispite great numbers of pike.  Considering that they've also survived the introduction of striped bass (which get bigger and inhabit salt-fresh waters) as well as largemouth bass, smallmouth bass, bluegill, crappie, channel catfish and carp, it's very unlikely that the addition of pike to that mix will even have a perceptible effect.  The environmental movement uses hyperbole and slippery-slope arguments as it's bread and butter to get people motivated.   Moreover there isn't really much that can be done about invasive species, but since there isn't an invasive species lobby (like there is a water export lobby) it's easy for government to throw money at that problem and say they're doing something.  Do we really want to spend millions of dollars per year trying to eradicate pike, mussels and weeds for the forseeable future when it's a futile battle?  Thats politically easier than removing dams, but damn sure isn't better.

Native or non- native are simply words and arguments over whether something is non-native or native will be subject to the definitions used by various agenicies and political groups to suit their own interests.

North America is a great example of extreme confusion on what comprises native or natural. Take corn the accepted history is that it was developed in something like 2000 AD in the Pan-American area. So, does that make corn a native speicies of the area? It was selectively evolved by man.

Or take the idea that going back  five hundred years gets you into a natural North America. It's a fact that the Indians practiced selective land management, by fire and planting seeds to promote things like more nut trees, better acorns and so on.

Various indigenous people had different land and crop practices across all of America. It is believed and well supported that their were more people in America than Europe before the Spanish arrived and killed then off with diseases that had never been seen here before. Then a hundred or more years pass and the settlers show up. By this time the buffalo had grown into huge herds that the Indians had never seen before.  Deer populations were also larger. Pretty much a new ecology had grown and evolved.

So in the last four thousand years man has selectively grown plants, transported diseases, viruses, bugs, animals, burned plains and forests, fenced, built cities, dammed rivers and so on. There are vast expanses of Latin American Forests that can be identified from satellite pictures that show that building materials have fertilized areas that grow different plants. Materials from cities built thousands of years ago. Even the Amazon forest has areas that have unnatural concentrations of fruit bearing trees (man's hand).

My definition of native is anything that has taken hold in an area that can't be eradicated or exists in healthy populations that are tolerated. In California, that would include Stripers, Starlings, Eucalyptus Trees, English Ivy, various fruit trees, Pampous Grass, Scotch Broom, Ice Plant and God knows what else.

Man is part of the ecology. Like a giant ant hill we expand and consume the earth. The question is will we continue to evolve the technology to save ourselves from our ways. This is a two edged sword, though, because when the technology evolves to save the planet it also evolves to consume it or harm faster.

I'm a 4th generation Californian.  Am I a native yet?  Let's face it, the California ecosystem is highly invaded by non-natives.  Its a pretty sweet place to live and prosper for all kinds of plants and animals.  Some species introductions are rather benign and others are like Holy Crap!  When species become established, their spread can be hard to contain, and eradication is near impossible. 

This is one of my favorite sites http://nas.er.usgs.gov/.  Check it to find out where the new species are being established.  Another good one is http://www.dfg.ca.gov/hcpb/species/nuis_exo/nuis_exo.shtml.  Its kind of hard not to get apathetic about the issue, but there are endemic species at stake as well as some of our favorite fisheries.

Just a thought, but as we are transporting our kayaks and gear around to various water bodies, we may unknowingly transport these invasive species to new homes. 

ichthyophile