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Archive for the ‘wildlife’ Category

lined seahorse

Seahorse always fascinated me. When I was a kid, we’d go to the souvenir shops at the beach in North Carolina, and of course, there would be many shells and sand dollars to buy. And you could pick up a dried-out seahorse. The racks would be full of dried out seahorses, hundreds and hundreds of them.

I never really thought about seahorses as being potentially threatened by anything. My child brain could not fathom how much trouble they could be facing.  But even those species that live off the coast of the United States and Canada are under threat from pollution and over-development. They are also in demand for Chinese traditional medicine, and with the Chinese economy growing as rapidly as it has for the past few decades, this demand has only increased the pressure for both species.

Two species found in the Western Atlantic are the lined seahorse (Hippocampus erectus) and the longsnout or slender sea horse (H. reidi).  The lined sea horse has a more northerly distribution than the longsnout, but their ranges do overlap from North Carolina to Venezuela. The two species do not readily hybridize in the wild, though they certainly have done so in captivity.

With the lined sea horse being listed as “vulnerable” by the IUCN and the longsnout as “near threatened,” there are real conservation concerns for both species, and they are indeed being bred in captivity now with hopes of giving a boost to the dwindling wild populations.

However, these two species are often housed together in aquarium and zoos, and they have interbred.  A recent paper in the Journal for Zoo and Aquarium Research has identified a simple molecular technique for identifying hybrids in captive populations, but the paper also notes the possible issues with hybrids.

The obvious problem is that conservation plans for restoring species are designed to restore a particular species, not hybrids between the two. Yes, this is the big boondoggle behind conserving species that hybrid with another, but it is one thing to have hybrids readily occurring in the wild. And it is quite another if hybrids largely exist because of aquarium practices.

So the authors urge zoos and aquariums to stop putting these two species together and to work much harder at maintaining “purebred” populations of each species.

However, the authors point out that the hybrids could be useful for conservation in another way. With improved seahorse husbandry techniques, various farms could potentially breed populations of hybrid seahorses and fill the needs of the growing Chinese market.

These two species may have split from their common ancestor over 14 million years ago, but hybrids between fish species can happen between species that have been divergent for many millions of years.

Humanity’s effects upon the ocean have been greatly underestimated.  Much of what has happened to the ocean has been out of our sight for so long that we assumed that all was fine.

But future for many species of seahorse is not secure at all, and if we are to be proactive and work on restoring diminishing stocks of various species, we must work on controlling potential problems that can come from hybridization in captivity.

So for conservation purposes, we must try to keep strains distinct for those that could be released into the wild, but for the Chinese medicine market, breed the mutts.
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This video was posted on an outdoor channel in Eastern Washington:

This guy is a good naturalist, and he has excellent trail camera placement.

But what he’s actually seeing are not hybrids. What he is seeing is the wonderful transition from the mule deer type that is common in the interior West to the black-tailed deer type, which is common more toward the Pacific Coast.

Those two deer are now recognized as a single species (Odocoileus hemionus), though the mule deer type is recognized to have some hybridization from the white-tailed because it possesses white-tail-like mitochondrial DNA.

Hybridization does occur between white-tails and mule deer, but the survival rate is quite low among the F1s. Mule deer have a stotting evasion behavior, which is incompatible with the white-tail’s bounding pattern. The offspring inherit both behaviors, and they cannot effectively evade predators.  The stotting behavior is used to communicate to a predator that might be hunting the mule deer on the open range that this deer awfully healthy and that it should try a different target. White-tailed deer are forest deer, and they just bound away from predators.

But apparently, there was an introgression of a white-tailed deer matriline into what became mule deer at the Pleistocene/Holocene boundary.

So this transition from true interior West mule deer to the Pacific blacktails apparently starts in Eastern Washington, and of course, you’re going to see the transition somewhere. These two forms interbreed because they are subspecies, and at some point, you’re going to hit the transtional zone between the two, where it gets hard to tell which is which.

 

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The 17-year-cicadas (Magicicada) are coming out this year in this part of Ohio, as well as the Northern Panhandle of WV and parts of Western PA.  They emerged last night on our lawn and began their adult form on our silver maples.

(All photos by Jenna Coleman).

magicicada 2019

The discarded exoskeleton of the Magicicada nymph:

magicicade nymph husk

An adult one is bursting through its nymph exoskeleton.

bursting throuhg the exoskeleton

The adult exoskeleton is pasty and takes a few hours to harden into black.

pasty exoskeleton magicicada

hardened into black

Our maples are covered with discarded nymph exoskeletons, drying adults, and adults that are almost ready to start whirring in the trees.

maples coavered

The adult form is so oddly ugly that it is beautiful.

magiicada

magicada 2

magicciada 3

These cicadas have a life-cycle based upon brood. They spend 17 years underground. When that time comes in late May, they climb up out of the ground and begin mating and laying eggs. Their will be whirring loudly from the trees in a couple of days, and by the end of June, you won’t see a single one. This reproductive strategy is meant to overwhelm their many predators with so many easy targets that more than a few will manage to reproduce.

This blog covered another Magicicada outbreak in 2017, but that was a different brood. This one is Brood VII. That one was Brood V. 

So we are ready for the weird noise of these cicadas as they complete their final life stage.

And we will soon be tired of it.

 

 

 

 

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Posted on The Atlantic’s Youtube channel, this week:

He’s one of my heroes. I won’t lie about it.

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woodland caribou

I had the pleasure of listening to Diane Boyd, a noted wolf expert, talk about wolf conservation issues on Steven Rinella’s Meatear Podcast. It is very good info about wolves, including wolf conspiracy theories.  One part I found particularly interesting was about the history of Isle Royale, which is experiencing a wolf reintroduction this year. Isle Royale is, of course, home to one of the longest running ecological studies that has examined predator and prey relationships.  The study mainly focuses on moose and wolves on the island, but an inbreeding depression reduced the wolf population of the island to two individuals last year.

I have always thought of Isle Royale as being a place of wolves and moose. But wolves came to the island only in the 1949, and moose came only in the early 1900s.

In the podcast with Diane Boyd, she mentions that Isle Royale was originally known for its woodland caribou and Canada lynx.  Boyd speculated that moose introduced brainworm to the caribou, but a more likely reason for their disappearance is that woodland caribou are sensitive to human-centered activities. All the logging and mining that happened on Isle Royale could not have done the caribou many favors. The last caribou was documented on the island in 1925.

Canada lynx are not particularly good predators of caribou. They were likely living on snowshoe hares, which are found on the island. Maybe, when snowshoe hares experienced the crash portion of their boom or bust population cycle, the lynx occasionally turned to hunting caribou, as they did in Newfoundland.

If Isle Royale’s fauna had remained the same at the beginning of the twentieth century as it did at the beginning, maybe it never would have become such a great place to study predator and prey population dynamics.

The restoration of wolves to Isle Royale, which is happening as I write this piece, is an attempt to bring back an ecology that dates all the way back to 1949. I have readers who can remember 1949.

We have this idea that conservation is about restoring things to an Eden when things were unmolested, untrammeled, and pure.  But what seems to be timeless is ultimately just temporary.

Last night, I was grappling with the concepts of conservation, specifically the idea of rewilding.  Rewilding is about restoring organisms to the land that were there at some point. Some think of feral horses in the West as being rewilded, from the Pleistocene though I am greatly skeptical of this idea.

Of late, though, there have been proposal to restore Pleistocene fauna to their former ranges, and if that animal can’t be found exactly, then a facsimile will be brought in.

In the case of North America, African elephants have been proposed as being equivalent of the Columbian and woolly mammoths. African lions might take the place of old Panthera atrox.   Some have even suggested that the plains of Texas, which are filling with blackbuck, might be a great place to turn out some cheetahs, thinking of course that Old World cheetahs are somehow the equivalent the long-legged coursing cougars that once roamed the Pleistocene wild of North America.

We don’t really know what killed off all these fantastic beasts of the Pleistocene. I lean more toward rapid warming at the time of the Pleistocene/Holocene boundary, but many reasonable people find some merit in Paul Martin’s “Overkill Hypothesis.”  This hypothesis contents that the Siberian hunter-gatherers who came into North America wound up killing off much of the megabeasts, or lacking such evidence of profligate killing, contend that these hunter-gatherers killed off a few keystone species, such as mammoths and mastodons, to cause ecosystems to collapse.

If this hypothesis is correct, there is a moral force for this Pleistocene rewilding concept. Humanity is responsible for killing off the megabeasts, and it is our duty to restore North America to its former glory as the land with the great bison, pachyderms, camels, and equines.

But this takes me back to Isle Royale. Humans certainly disrupted that ecosystem. If we wished to restore Isle Royale to its form ecosystem, we should be shooting off all the moose on the island and turning out woodland caribou from Ontario. We shouldn’t be trapping wolves and turning them loose. We should be trapping Canada lynx instead.

Canada lynx are much rarer in the Upper Midwest than gray wolves are, so by a triage of the conservation needs of the species, it would make more sense to preserve Isle Royale for the lynx.

Of course, that’s not what is being done. The wolf and moose studies are too deeply ingrained in our science and our understanding these two species. And if you were to twist my arm, I’d say choose wolves and moose over caribou and lynx.

But this is logic of Pleistocene rewilding. It is to say that we can somehow turn back the clock on that happened long before North America had cities and agriculture and way long before the continent was divided into nation-states.

Indeed, while we’re theorizing about Pleistocene rewilding, we’re not really coming to terms with that fact that Pre-Columbian rewilding is a project that will only go so far. Yes, we’ll have wolves come back to the Upper Midwest and the Western States.

But no one is seriously considering restoring grizzly bears to Texas or even attempt to bring back wolverines to Michigan.

We cannot handle that idea of wildlife now. That we have managed to hold onto so many wild places and restore so many wildlife species is a certain greatness about the United States. However, this feature is one that always exists in tension, one that must be recognized and fully understood.

Isle Royal in 2019 is not the same as Isle Royal in 1960, which was not the same as Isle Royale when the loggers and the miners came.

And if that one island is so different, imagine how different the entire continent of North America has become since the Pleistocene gave way to the Holocene, which has now giving away to the Anthropocene.

There is a sadness in knowing that things pass, and we certainly have a moral duty to prevent extinction and to preserve what ecosystems we can.

But we should understand that what we’re preserving was never timeless, and even in our attempts at restoration, we aren’t always going back to the known original condition of a place. We often go back to what seemed wondrous and pure and wild.

And if we can understand this simple fact, maybe we can get a handle on what our species continues to do to the planet and the rest of life that resides here with us. We have done much, but we shouldn’t assume that we are preserving any kind of stasis.

I write these words from the northern edge of Appalachian Ohio, awaiting the arrival of the nine-banded armadillo, which will some day come working its way up from North Carolina and Tennessee into Virginia and then West Virginia.  Xenarthan,  the “strange jointed stranger”  with roots in Latin America, it will come scurrying along into this part of the world.

What it may change in our ecosystems, I cannot guess. But it is coming.  When it arrives, it will roam where wolves once howled and elk bulls bugled.

And its story on the land will be one to note. It will not be timeless. It will a temporal as the fleetingness of existence, a bit of the faunal guild of the Anthropocene making a name for itself in a new land, just as those Siberian hunters did all those thousands of years ago.

 

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feral horses

I make no bones about my view that the horses that roam the American West are feral and should not be regarded as native wildlife. This view shouldn’t controversial, but it is.

Lots of romanticism exist about horses and the West, including that brief time when Native cultures used horses as their greatest asset in hunting bison.

But the truth is that the horses one might see roaming the ranges of the American West are all derived from domestic horses that went wild on the range. The initial ones were all derived from Iberian/North African horses that Spanish colonizers brought into the New World, but these were later augmented with horses brought over from the rest of Europe.

If one were to say that the various forms of freely breeding swine in North America were feral, it would be easy to get agreement. Suids are not native to the Americas, though a sister lineage, the Tayassuidae, are native to North America. The tayassuids, better known as peccaries or javelinas, once ranged as far north as the Yukon, but since the Pleistocene, they have not ranged north of Texas, New Mexico, and Arizona.  Feral swine, though, exist over large sections of the country, and wildlife and agricultural departments spend lots of time, money, and manpower on controlling their numbers.

Feral horses, though, get special privileges, as do feral donkeys.  They receive a certain amount of protection not afforded to other feral livestock in the Wild and Free-Roaming Horses and Burros Act of 1971. The horses and donkeys are not controlled in the same way feral pigs are. There is no continuous open season on them in the way that most states manage feral pigs.  Indeed, it is actually a crime to kill or harass feral horses or burros on federal land.  Excess horses and burros are managed through roundups, where some of them are deemed adoptable and sold to the general public.

For those of us with a modern ecological mindset, which has a deep disdain for making allowances for feral livestock, this law makes little sense.

But there is a sort of argument for this act. It goes something like this:

The modern horse species evolved in its current form in North America. Some taxonomists contend that there was once a Holarctic distribution of this species during the Pleistocene, and with the latest ancient DNA studies, I tend to agree with this assertion.

The North American population of horses became extirpated at the end of the Pleistocene, and when European horses went feral on the Western ranges, this constitutes a rewilding event.

Now, I don’t buy this argument very much, but I can say that there are some things we might consider. North America’s original population of cougars became extinct at the same time. The cougars that live in North America are derived from South American cougars that recolonized the continent about 2,000 years later.

Further, conservationists and sporting groups spend lots of resources on restoring and protecting elk populations. Elk have a much shorter history on this continent than horses ever did. Different experts have estimated when elk have first arrived. 40,000 years ago has been suggested, but more recent data points to them colonizing North America only 15, 200 years ago.

If elk arrived in North America only that recently, their status as native wildlife exists only as a weird  accident of geography. Elk are the on Cervinae or “plesiometacarpal deer” in the Americas. All the other deer in the Americas are Capreolinae or “telemetacarpal deer.”  Sika, axis, red deer, and fallow deer are also Cervinae, but they were introduced after colonization.

Elk don’t live in far northeast of Russia anymore. The elk of North America are the genetic legacy of this ghost population.

So the feral horse advocates could at least through the recent arrival of elk in North America as something to consider when we say their favorite animal is not native. Horses have a long evolutionary history in North America, and we just happen to be at an odd point of the history of horses that no native horses exist here. The earliest horse, Eohippus, first appeared in North America 52 million years ago.

So the feral horse advocates could say that we have a species that derived from a lineage that was here for over 50 million years that has now been restored through feral livestock and thus deserves these protections.  And this animal has at least as much rights to be free and roaming in North America as a large deer that had no connection to this continent until the latest Pleistocene.

However, the extinction of the horse in North America likely stemmed from natural climate change at the end of the Pleistocene.  Horses became extinct because they were poorly adapted to the new ecosystems, and as we have seen, horses really don’t do that well out in the deserts and semi-arid ranges of the West. They require water tanks to get them through long droughts, and they eat lots of forage. Not as much as domestic cattle, of course, but on ranges that are heavily catered toward livestock grazing, the horses are just an extra set of grazers that are taking away forage from native wildlife.

And even if we were to accept that horses were restored native wildlife, why on earth would we ever extend these protections to donkeys? Donkeys, though of ancient North American origin, evolved in their current form in Africa.

So although I do think of horses as no longer being native to North America, I do think questions of them being native or introduced are complicated, much more so than the question of feral pigs or cats. And yes, there is something like an argument that can be made for the native status of horses, even though I think it’s mostly in error.

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How did Komodo dragons survive?

dragon eats goat

Komodo dragons are the world’s largest lizard.  They are supersized monitor lizards that first evolved in Australia four million years ago.  One million years ago they arrived on the Wallacea Islands, where they fed upon a dwarf species of elephant. That elephant went extinct 50,000 years ago. The mainland Australian population of these lizards went extinct around the same time as those dwarf elephants.  The main prey of Komodo dragons now consists of introduced ungulates that arrived on those islands between 7,000 and 10,000 years ago.

That means Komodo dragons spent 40,000-43,000 years without large terrestrial prey sources, and if that is the case, how did they survive?

Well, a new paper in the journal Global Ecology and Conservation attempts to answer that question.

Apparently, Komodo dragons are an odd mix of the best ectotherms and the best of endotherms.  As ecotherms, they have the ability to rely upon limited food resources, and it just so happens that the oceans around their last island redoubts are quite diverse marine ecosystems. So the dragons would have plenty of marine food that they could scavenge. They also have the ability to reduce their growth rates to compensate for the lack of large prey species on the island, a trait that has been shown in the subfossil record. Remains of dragons that date to these lean millennia show that dragons were significantly smaller then than they are now.

Also, unlike most ectotherms, Komodo dragons, like virtually all monitor lizards, have the ability to adjust their behavior and try new food sources. When tourists scared off the ungulate prey of Rinca Island, the dragons simply started hunting macaques and raiding scrubfowl nests.

Further, the dragons could also live nicely as cannibals. Smaller dragons get eaten by the larger ones, and because the dragons produce far more offspring than could ever reproduce, the excess dragon young could have fed the adults quite well.

Humans also never really thought of these arid and semi-arid islands as good places to set up large scale agriculture, and because these islands were also devoid of native prey species, humans were not widely using them as places to hunt until deer, buffalo, and pigs were introduced.  When humans did settle the islands, there were enough dragons in the population that had “shy personalities” that kept them from causing conflicts with humans. These “shy” dragons are disproportionately female, and they could have passed these more retiring traits onto their offspring, which is why Komodo dragons are not killing people left and right. People likely killed off the bolder males when they first began to settle these islands, and in a species were the sex ratio tends to be biased in favor of males, any trait that would have increased a female’s survival would have definite consequences in the population genetics of the species. That means that the “shy” trait could have easily become expressed in the population, simply because humans would have low tolerance for aggressive behavior.  Dragons today generally avoid people.

Finally, females of this species are capable of reproducing via parthenogenesis. Males in this species are larger, and if conditions became so bad that all the large males died off, some of the females would still be able to reproduce anyway.  Because of how the lizards’ sex chromosomes work, they can only produce male offspring when they reproduce this way, which could be a way to restore males to a population that lost them through a lack of food resources.

Komodo dragons were once quite widespread across Australia and several nearby islands, but now they exist only on the islands of Wallacea. These islands are named for Alfred Russel Wallace, a co-discoverer of evolution by natural selection. Wallace noticed that the native animals of Sunda, which is the Malayan Peninsula and the Malayan Archipelago, are fundamentally different from the native animals of the islands just to their east.  The animals of Sunda generally have an Asian origin, while those of the islands to the east are more of Australian origin. The line between these islands is called the Wallace Line.

The dragons of Wallacea are of Australian origin. Their current main prey sources are all most of Asia origin. So in the Holocene, humans broke down Mr. Wallace’s Line, and the dragons grew back into their larger form. This larger dragon was the same one that hunted the megafauna of the Australian mainland, playing second fiddle to only the larger monitor called megalania (Varanus priscus).

I have often wondered what it would have been like to have seen the mammoths that lived on Wrangel and St. Paul Islands. These mammoths were the last survivors of a species that range over much of Eurasia and North America until 10,000 years ago, but they continued to survive on St. Paul Island for 5,600 years. They died off on Wrangel Island only 4,000 years ago, and they only died out because of a weird genetic mutation similar to the rex mutation in rabbits that made it harder for them to insulate their bodies on that cold island.

But by several accidents of their biology, the Komodo dragons have not undergone the same fate. They still exist as a relict population.

We have a hard time living with large predatory animals. They tend to inconvenience our way of life pretty badly. However, the people of these islands do benefit from the dragons. They attract a lot of tourists and their dollars. There is real economic benefit to having such creatures roaming about.

But I don’t know how long this can last.  Because the dragons have these shy behaviors where they avoid humans, increased tourism on these islands could greatly stress them, making it harder for them to thrive and breed. These concerns came at about the same time of a mass arrest of an animals smuggling ring that had 40 dragons in its possession, which has led the Indonesian government to ban tourists from coming to Komodo Island in 2020.

If the islanders cannot make money from tourists, though, it is very likely they will try to make some money selling the dragons to smugglers, and if authorities are not on top of things, the Komodo dragon might not survive the Anthropocene.

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