A conversation about conserving and naming species.-
Without
significant changes, more than 50 percent of the world's marine species
may be perched on the brink of extinction by 2100, according to UNESCO.
Credit: Dan Norton (for commercial use, contact photobank@coral.org)
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Daphne Fautin searches for new organisms while conducting a marine survey.
Credit: Rita Tan of www.wildsingapore.com
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Name that Species! A conversation about conserving, finding and naming species with NSF Program Manager Daphne Fautin
Credit: National Science Foundation
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A little more than 39 years ago, on December 28, 1973, the
Endangered Species Act was enacted to conserve threatened and endangered
species and their ecosystems. To honor this anniversary, Daphne Fautin
of the National Science Foundation answered questions about
biodiversity.
As a marine biologist, Fautin has
literally gone to the ends of the Earth--from the poles to the
tropics--to study marine life. She is currently a program manager at the
National Science Foundation, a professor of ecology and evolutionary
biology at the University of Kansas, and a commissioner with the International Commission on Zoological Nomenclature, which produces rules on giving scientific names to animals.
What is biodiversity?
Biodiversity--short
for "biological diversity"--is the variety and abundance of plants,
animals and other living things on Earth and in particular locations.
Biodiversity is absolutely essential to ecosystem health. And human
survival depends on the health of our planet's ecosystem.
Rain
forests and coral reefs are known for their biodiversity. Why is so
much biodiversity concentrated in these types of ecosystems?
More than 25 percent of the
world's fish species
and between nine and 12 percent of all of the world's fisheries are
associated with coral reefs. More than half of the world's plant and
animal
species live in
rainforests.
We
don't know for sure why rain forests and coral reefs harbor so much
biodiversity. One idea is that these ecosystems occur in tropical
climates, and so they are quite climatically consistent year-round.
According
to this idea, tropical organisms diverged because they don't have to
deal with the climatic extremes that organisms at higher latitudes (and
altitudes) do. A rabbit, for example, that lives in a non-tropical
place must be able to eat certain plants in the summer and certain other
plants in the winter. Therefore, it must remain a generalist to
survive.
By contrast, a rabbit that lives in the tropics may
specialize in eating certain plants that are available year-round; at
the same time, other species of rabbits (or other organisms) may evolve
that specialize in eating other plants. Such specialization promotes
diversity.
But some evidence does refute this idea--such as the
fact that not all groups of plants and animals demonstrate more
diversity in the tropics than at higher latitudes. So, many other ideas
have also been proposed to explain the extraordinary biodiversity of the
tropics.
Insects account for a large proportion of the biodiversity on Earth. Why?
Many statistics bear out the biodiversity of insects. For example, more than
850,000 insect species have been named.
And the total estimated weight of just
ants
in the Amazon is four times the estimated weight of all land
vertebrates in the Amazon--including all mammals, birds, reptiles and
amphibians!
We don't really know why insects account for so much
of the Earth's biodiversity. That is one of the questions that is being
studied by entomologists--the people who research insects.
One
idea is that insects began to diversify when flowering plants evolved on
Earth, and so insects evolved along with flowering plants because they
are so important in the pollination of plants.
Insects tend to be
small and specialized: So there may be a certain insect that sucks out
the cell sap from the stems of a particular plant; other insects that
eat that plant's leaves; other insects that feed on that plant's nectar;
and other insects that feed on that plant's pollen and pollinate the
plant in the process. So as flowers evolved, many insects evolved as
well.
This idea about the evolutionary connections between
flowering plants and insects is consistent with what we see in the
oceans: Relatively few species of flowering plants live in the oceans,
and relatively few species of insects live in the oceans.
(By the way, NSF recently issued a
press release that identified some interesting reasons why humans need insects--even pesky ones.)
How many species have been described and named by scientists, so far?
The Encyclopedia of Life
estimates that there are 1.9 million known eukaryotic organisms.
(Eukaryotic organisms are those that are made of one or more cells with a
nucleus; bacteria and viruses are not eukaryotic organisms.)
How many species exist on Earth?
Estimates range from 2 million species to 10 million species.
A recent estimate of 8.7 million
species received a lot of press, in part, I suspect, because of its
supposed accuracy and because it corresponds quite well to the
often-bandied figure that 80 percent of the Earth's biodiversity has yet
to be discovered/named. The
Encyclopedia of Life states that
"at least four times" the number of known species exist on Earth. Based
on its own figures, this translates to around 8 million species.
A
paper estimating the number of marine species (which I contributed to)
was recently published. According to this paper, 226,000 species that
live in the ocean have been named and described by scientists, and
72,000 additional species are in collections waiting to be named and
described.
But who knows what hasn't been collected yet? And of
course, as I previously mentioned, oceans have few insects, but insects
account for the bulk of biodiversity.
How can scientists
estimate the total number of species on Earth when it is obviously
impossible to count what has not yet been counted. In other words, how
can we know what we don't know?
People have used various
creative methods to estimate the total number of organisms on Earth. For
example, there was a very large estimate made years ago by a scientist
who went to the jungles of Panama and used insecticide to spray a tree
in the jungle. Then, lots of insects died and fell from the tree to
the ground. And the scientist and his colleagues identified and counted
as many of these fallen insects as they could, and the rest were
counted as unknown. Then, the scientist extrapolated from the
proportion of species in that one tree that were known vs. unknown to
produce a global estimate of known vs. unknown species.
It was
good first try. But a lot of people point to the fact that in many parts
of the world, the proportion of known species to unkown species is
higher than it is in Panama. So this fact would suggest that the
estimate may be excessive.
In 2011, an NSF-funded researcher provided the first empirical evidence of what had been long suspected: That biodiversity promotes water quality. What are some of the other reasons why need biodiversity?
We
need biodiversity to eat, we need to preserve species that we use as
food, including fish from the sea. We also need to preserve those
species that serve as food for the fish we eat, so that our food supply
persists. And we also need to preserve all the species that create the
habitat that enables all of these needed species to live, spawn, and
raise their young.
So, there are all of these connections in the
great "web of life" that we don't even know yet. And these connections
support all of the species on Earth, including species that provide us
with food and clothing.
Also, 50 percent of the oxygen we breathe
is produced by microscopic plants that live in the ocean and the other
50 percent is produced by plants that live on land.
(If you want
to learn more about the ways in which the various species of plants help
humans survive, watch this dynamic, upbeat
video produced by NSF.)
The
planet's ecosystem is sometimes compared to an airplane. You can lose
one rivet from an airplane, and the airplane will probably fly. You can
lose two rivets for an airplane and the airplane will still probably
fly. But eventually, if you lose too many rivets (how many?), the plane
will crash.
The same principle applies to ecology: You can lose
some species without major harm. But no one knows how many species can
be lost before the planet's ecosystem will crash.
What does it mean to discover a new species?
A
new species is one that hasn't yet been formally described and named
according to scientific procedures--not one that is newly evolved.
People
on the street or people in the jungle may have a name for it. But if
we haven't followed the internationally recognized rules of nomenclature
for describing and naming a species, it doesn't exist for certain
scientific purposes.
When we have discovered a new species, it
means we have finally found and gone through the procedures of formally
describing it (distinguishing it from other species) and giving it a
name following the rules of nomenclature.
How many new species are named each year?
Between 15,000 and 20,000 new species are named each year.
A
species may be discovered and collected before it is described and
named. But it isn't recognized as a new, distinct species until it is
described and named.
How many species go extinct each year?
We don't know. The
World Wildlife Fund's Web site says that experts have calculated that between .01 percent and .10 percent of all species on Earth go extinct each year.
But
because we don't know how many species there are, we don't know how
many species those percentages actually represent. And so, if the low
estimate of the number of species on Earth is true--if there are around 2
million species on our planet--then between 200 and 2,000 extinctions
occur each year.
But if, in fact, there really are 10 million species on Earth, then between 10,000 and 100,000 extinctions occur each year.
What
would you say to naysayers who argue that newly discovered species
offset species losses, and so there really is no extinction crisis?
"New"
species are not newly evolved. They evolved a long time ago. They are
simply being newly discovered by science. They may be very well known
to the people living in the areas where they live. So they aren't new in
that sense; they are only new to those of us who name them.
What does the process of naming a species involve?
It
can be long, protracted and difficult process that can take many years.
First, you want to be sure that the animal or plant hasn't been named
before.
This can be difficult for a variety of reasons. For one
thing, many descriptions that were prepared in the early days were very
vague. And usually, only small groups of experts have the specialized
expertise to know what has and hasn't been described before.
And
in order to name a species, you also have to describe it. To do this,
you have to know what kinds of features are used to identify species,
and figure out what distinguishes the "new" species from known species.
This is important, because at least according to the rules of
zoological nomenclature, when you publish a description of a new
species, you have to write out what makes it different from everything
that is already known--including organisms that are not closely related
to it, but that look like it anyway.
For example, suppose you have
an organism that has a red spot; then you have to distinguish your
"new" species from everything that is red-spotted, even if those other
red-spotted species are not closely related to your species. That way,
when somebody comes across your species, they can say, "AHA! This is
another one of those red-spotted organisms that is covered by that new
name; it's not another thing with red spots."
Other rules in the
codes of nomenclature require you to name species in Latin or make them
sound like Latin. You also have make sure a specimen of your species is
deposited in a natural history collection (typically in a museum or
herbarium). If the "new" species is an animal, you may also have to
register the name in
ZooBank.
And
then you have to publish your description of the species in a
scientific journal, so that other scientists can look at it and agree
that it is correct.
It is interesting to note that names that are
accepted are frequently later "sunk" for various reasons. For example,
when the exhaustive homework that is required for describing and naming
a "new" species is not conducted in a comprensive and thorough way, it
may ultimately turn out that the "new" species has already been
described and named.
Alternatively, a name for a "new" species may
be sunk because the difference that was thought to distinguish it from
others does not hold up. For example, I have a colleague who described
several coral reef fish as "new"--only to ultimately discover that the
"new" species was a member of a species for which only one sex had
previously identified. So the "new" species was really just a female
(or male) of a known species!
Do you have to be a professional taxonomist to identify and name new species?
About
half of the species that are named each year are named by people who
aren't employed as taxonomists--whose job isn't in a museum or
university. In fact, some of the people with the most expertise and
time to do this are not professionals in the field.
For example, I
knew a dentist who is one of the world's foremost authorities on tiger
beetles. He had earned a master's degree in entomology. And then he
realized that if he had gone into academic entomology, he would be
spending his time teaching, writing grant proposals and doing
administrative work--but he wanted to catch tiger beetles.
And
so he went into dentistry so that he could make enough money to take
time off each year to catch tiger beetles. He probably thereby ended up
being able to spend more time chasing tiger beetles as a dentist than
he would have if he had become a professional entomologist.
A new species of frog
was recently identified by an NSF-funded researcher right smack in New
York City. Is that common for new species to be discovered in such
populated places?
I think that it is quite common for new species to be found in populated areas.
It may be less common than it used to be.
Many
years ago, it would be common for a patron to fund the travels of a
scientist to exotic places, and then species that were found during
those travels would be named for the patron.
Tell me about one of the big problems that is reducing biodiversity in the oceans?
We have depleted the oceans of many of the big fish that we eat.
Part
of the reason we are able to overfish is due to technology. We have
fish-finders: various types of tracking devices, including sonar
equipment, and airplanes that are used to help find schools of fish.
And we now know enough about marine biology to predict where fish and
crustaceans will be under particular conditions. Fishing is no longer
about a fisherman just saying, I'll drop a line here or there." Fishing
has become very scientific and methodical.
When we trawl, we drag
nets along the ocean floor. And whatever else gets swept by these nets
in addition to the target fish is called "bycatch." This bycatch gets
thrown back into the ocean because we are not licensed to take it or
because it's not profitable to take.
But how many organisms can
manage to survive after being caught in a big net, pulled up and then
thrown back into the ocean? What's more, trawling destroys habitat;
after the ocean floor has been trawled, it may no longer be a suitable
home for what is thrown back.
The analogous situation on land
would be if we flew an airplane that dragged a big net across the ground
to catch grazing cattle. And we would draw up the net periodically--and
keep the cattle, but toss back the dogs, trees and everything else that
we happened to net in addition to the cattle. That is similar to what
we do to the oceans.
Many people assume that it is necessarily
better to consume farmed fish and shrimp than wild caught fish and
shrimp. But many fish and shrimp farming practices are also harmful to
the environment. Just because it is farmed doesn't mean that it is
environmentally neutral or preferred over wild caught.
Can you cite any "good news" stories in biodiversity?
I
read the other day that we have lost 97 percent of wild tigers in just
over a century. Only about 3,200 tigers currently remain in the wild.
We can infer that the populations of many smaller species are plummeting
just like populations of many large species are plummeting.
But I am happy to say that a few species have come off the endangered species list, like the wolf and the bald eagle, because plans for their recovery were enacted.
Also,
there are "good news" stories in the history of whales. Many of them
were hunted to the brink of extinction, and then they were listed as
endangered. It therefore became legally, socially and economically
difficult to harvest whales, and so populations of many whale species
have fortunately recovered.
These kinds of successes show that if
we stop harvesting species, and if their habitat is conserved, life is
resilient and endangered species may recover.
Additional Resources
To learn more about biodiversity and help promote conservation:
Investigators
Daphne Fautin
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@hotmail.com
ayabaca@yahoo.com
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