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Endless Forms
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August 16, 2009
12:36 PM
786 views

Can Diversity Beat Adversity for Tigers?

by Anne-Marie Hodge in Endless Forms

I did my undergraduate degree at Auburn University, which is both a fantastic research institution and (in my exceedingly biased opinion), the crown jewel of Southern college football. I have spent many autumn Saturdays crammed in Jordan-Hare Stadium with 87,000 other people (keep in mind that the entire population of the town is around 40,000), and never ceased to be amazed at such a huge aggregation of humans, all there just to watch a game. The conservation biologist in me always felt some melancholy in contemplating the numbers, however, because the fans for just one game outnumber the population of some entire species by orders of magnitude. This is, ironically the case with Auburn’s mascot species, the tiger. If you took every single wild tiger left on the planet and put them in Jordan-Hare, they would fill little more than a single one of the 45 sections in the bleachers.
The tiger (which includes 6 extant and 2 extinct subspecies) is one of the most enigmatic and majestic species gracing our planet, and they have long been a flagship species for conservation efforts. A new PLoS Genetics paper by Mondol et al. brings news that may be seen as both ominous and auspicious for tiger conservation efforts.
The bad news: tiger populations have essentially been devastated to the point of near-extinction. The authors found that current tiger populations amount to only 1.7% of the tigers found historically, and are restricted to an almost insignificant 7% of their original range.
The good news: widespread sampling efforts showed that the Indian tigers retain 76% of the genetic diversity found in tigers worldwide. This indicates that the tigers’ genes are not disappearing as fast as their population numbers. For programs dedicated to preserving genetic diversity of declining species, this is a cause for celebration and hope.
These insights into the genetic structure of Indian tigers also yield clues to the tiger’s history. Mondol et al.’s analysis of the diversity patterns indicated that about 200 years ago, tigers in this region underwent a significant population crash, most probably human-induced.
This is indeed fascinating. I am becoming skeptical and jaded in my old age, however, and I am increasingly concerned that the public will get the impression that we can claim conservation success merely by preserving genetic diversity. Much has been made of “minimum viable populations,” “maximum sustainable yield,” and the like, with too little regard for the integrity and function of food-webs, and the resulting impacts on not only predators and prey but the ecosystem as a whole. Humans had been doing their best to eradicate large carnivores long before our historical and scientific records began. We would not know how large Indian tiger populations were several centuries ago if analyses like the ones in the current PLoS paper did not allow us to create estimates from molecular evidence. This makes it extremely hard to set appropriate goals for conservation and management plans.
Large carnivores are often the first species to go extinct or decline under stressful ecological conditions (whether anthropogenic or otherwise), and after they are gone their communities often shift from top-down regulated trophic structure to an alternate stable state with bottom-up regulation (Beisner et al. 2003, Steneck et al. 2002). In a sense, the only “natural” state we have ever observed has been one of depleted predator populations. Therefore, conservation efforts that seek to restore populations to a “minimum viable” number or to densities that match historical records may still be setting the bar far too low for predators to fill their ecological roles in regulating mesopredators and herbivores, which in turn affects smaller non-prey animals and plants, which affects water and soil nutrient content and the physical structure of the habitat itself. We might be able to preserve all of the genetic diversity of a species in a lab, and may even re-establish self-sustaining populations in the wild, but that does not mean that we have restored them to the densities and distributions required for them to perform the ecological roles that they played in their communities prior to relatively recent population crashes. Habitat loss and degradation is one of the most critical factors threatening biodiversity today, and as Mills (2003) points out:
“Biodiversity is a broad concept incorporating compositional, structureal, and functional attributes of ecosystems at four levels of organization—namely, landscapes, communities, species, and genes” . . . “the greater the range of ecosystems that can be conserved to accomodate large carnivores, the greater will be the number of opportunities for these variable interactions to be played out and for adaptations to changing conditions to evolve.”
Even if we had a complete tiger genome on hand, it would not do much good if the animals are relegated to zoo cages or small ecotourism resorts. Even if a token number of animals are allowed to roam in the wild, the species would simply be lingering as a present and yet enfeebled shade of its former self, with its role in community interactions and regulation essentially paralyzed.
Don’t get me wrong, genetic diversity is still an crucial factor, and the results of this paper are both important and fascinating. This information gives us further clues as to the size and distribution of historic tiger populations, which can lead to further analyses of predator-prey relationships and ecosystem interactions. The news about the remaining genetic diversity is encouraging; inbreeding depression can potentially prevent species from ever recovering from extremely low population numbers, even if their habitat is restored.
I suppose I just worry that we will lose sight of the forest for the trees, (or maybe lose sight of the tigers for the stripes, if I may put a spin on the metaphor?), and run the risk of congratulating ourselves for meeting artificially low bars due to shifting baselines of predator densities. The important thing is to keep in mind that conservation efforts cannot be broken down into parts; species they must be treated as integrated wholes, “package deals” including genes, physiology, behavior, and role in community interactions.

Mondol, S., Karanth, K., & Ramakrishnan, U. (2009). Why the Indian Subcontinent Holds the Key to Global Tiger Recovery PLoS Genetics, 5 (8) DOI: 10.1371/journal.pgen.1000585
See also:
Beisner, B.E., D.T. Haydon, and K. Cuddington. 2003. Alternative stable states in ecology. Frontiers in Ecology and the Environment 1(7):376-382.
Mills, M. G. L. 2003. Large carnivores and biodiversity in African Savanna Ecosystems. In Large Carnivores and the Conservation of Biodiversity, J. Ray, K. Redford, R. Steneck, and J. Berger, eds. Island Press, Washington. pp 208-229.
Steneck, R., M. Graham, b. Bourque, D. Corbett, J. Erlandson, J. Estes, and M. Tegner. 2002. Kelp forest ecosystem: biodiversity, stability, resilience, and future. Environmental Conservation 29: 436-459.
(For information on the Auburn chapter of the Society for Conservation Biology’s Tigers for Tigers program here.)

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Mondol, S., Karanth, K., & Ramakrishnan, U. (2009) Why the Indian Subcontinent Holds the Key to Global Tiger Recovery. PLoS Genetics, 5(8). DOI: 10.1371/journal.pgen.1000585

August 30, 2009
07:56 PM
729 views

Bears Avoid the Road Less Traveled

by Anne-Marie Hodge in Endless Forms

National Geographic has an interesting report on predator-prey issues in national parks: apparently pregnant moose in Yellowstone National Park and Grand Teton National Park tend to shift their activity closer to roads before giving birth, in order to avoid predation by grizzly bears.
According to the results of the study, bears tend to be much more wary of roadways than moose. Grizzlies usually give keep at least a 5000 meter clearance, while moose have been recorded giving birth within a scant 45 meters of a road.
One question that needs to be asked immediately is: how do we know moose are doing this to avoid predation? What if they’re just not very bright and haven’t figured out to avoid the roads themselves?
The study answers that question by showing that moose only show this pattern of behavior in areas where bears are present, and that pregnant females have shown closer and closer associations with roads over the years as bear populations have increased in the parks where the research was conducted. Also, it is noteworthy that only pregnant females showed this pattern, which also supports the hypothesis that this is an anti-predator behavior being used to decrease mortality of newborns.
I’m pursuing a career in carnivore conservation, and am extremely intrigued by any story about animals adjusting complex behaviors in response to anthropogenic influences. It would be interesting to look at why bears are so more adverse to roads than moose. The article mentions that bears are more disturbed by the noise of the traffic, but I’d be interested to learn if there is more to it than that. Could it be due to different experiences with poaching, better associative learning abilities, larger home ranges in general, foraging preferences, or something else altogether?
One of the take-home messages from this study is that it’s important to consider information like this when planning parks and other managed areas. Something as simple as the layout of access roads can have a profound impact on the dynamics of populations and how they interact with each other, in ways that can’t always be predicted. Researchers from Denali National Park have studied the moose/bear populations there and have not found the same pattern of behavior as that reported from Grand Teton. Obviously, management plans should be tailored to specific populations, as opposed to automatically assuming that what works for a species in one setting will apply equally as well in another place/time.
Another example of this is an absolutely fascinating Journal of Mammalogy paper that I read recently, Selection of den sites by black bears in the southern Appalachians. This study (which also measured other parameters affecting site selection, such as elevation and slope), done in the Pisgah Bear Sanctuary in North Carolina, showed that females with cubs actually avoid gravel roads more than paved roads, despite the fact that paved roads are usually busier. This seems counterintuitive at first, with females choosing to den much farther from quieter gravel roads and closer to the higher traffic volumes associated with the paved roads in the sanctuary.
Why would mother bears prefer to be near higher traffic paved roads than less-traveled gravel ones? The authors of the study suggest that it is due to the fact that human behavior on paved roads is much more predictable. If you’re cruising down a paved road at a relatively high speed, keeping up with the flow of other cars, chances are that you’re not going to stop, get out, and dally around the roadside.
Gravel roads, on the other hand, are more likely to be used by hikers, campers, and other people that intend to roam around the forest (maybe even pesky biologists? ;P ). Also, the authors suggest that poaching pressure (it appears that this does occur even inside the preserve, unfortunately) could be a factor as well. Male bears and females without cubs didn’t show the stronger aversion to gravel roads, but females with cubs did, suggesting that the avoidance behavior is a defensive mechanism aimed at protecting their offspring from unpredictable intruders.
If the bears have learned that human activity is less predictable when people approach on a gravel than a paved road, it makes sense that females will avoid these areas when they are choosing den sites to house their cubs. I found this to be extremely interesting; I wouldn’t have expected a stronger aversion to gravel roads, but the explanation is pretty convincing when you see all of their data.
Moral of these stories: road layouts within wildlife preserves are complicated by multiple factors, and animals sometimes react to them in ways that initially seem counter-intuitive to we mere humans.

Reynolds-Hogland, M., Mitchell, M., Powell, R., & Brown, D. (2007). SELECTION OF DEN SITES BY BLACK BEARS IN THE SOUTHERN APPALACHIANS Journal of Mammalogy, 88 (4), 1062-1073 DOI: 10.1644/06-MAMM-A-329R1.1
(Repost from my old blog archives, originally posted 10/13/2007)
(Image source)
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Reynolds-Hogland, M., Mitchell, M., Powell, R., & Brown, D. (2007) SELECTION OF DEN SITES BY BLACK BEARS IN THE SOUTHERN APPALACHIANS. Journal of Mammalogy, 88(4), 1062-1073. DOI: 10.1644/06-MAMM-A-329R1.1

November 10, 2009
11:25 PM
691 views

High Octane Dinosaurs

by Anne-Marie Hodge in Endless Forms

The question of whether dinosaurs were endothermic has been a rich source of controversy for decades. Although they were originally portrayed as sluggish reptiles that crept their “cold-blooded” way through the Mesozoic, over time evidence has suggested that they may have actually had active and athletic lifestyles, with fast-running metabolisms to match. Everything from growth rates to diet to integument has been used as evidence that dinosaurs, if not as fully “warm-blooded” as mammals, at least ran on a higher octane than many modern ectotherms. (“Cold-blooded” and “warm-blooded” are misleading terms; some ectothermic reptiles, such as large marine turtles, maintain consistently high body temperatures through behavioral adaptations, and some endothermic species, such as hummingbirds and bats, have a wildly variable body temperature that periodically drops low enough to drop them into torpor. Poikilothermic = variable temperature, homeothermic = consistent temperature, and endo- or ectotherms can be either.)
There is a new paper in PLoS ONE today that jumps into the fray of the dinosaur energetics question. Pontzer and Hutchinson (2009) test the hypothesis that dinosaurs were endothermic, using biomechanical analysis to model the metabolic rate of 13 bipedal dinosaurs, in addition to an outgroup ornithodiran, Marasuchus. They calculated metabolic demands of both walking and running using locomotor anatomy (limb length and active muscle volume), and compared their results to the aerobic capacity of extant ectotherms and endotherms. These comparisons can give us clues where the dinosaurs might have fallen along this metabolic spectrum.
So, what did they find? The results showed strong evidence that dinosaurs had aerobic capacities that exceeded the maximum limits of extant ecotherms. In other words, they were most likely endothermic to at least some degree, otherwise they could not have afforded the amount of energy that it apparently cost them just to move around. It is suggested that development of endothermy could be a reason for the long and extensive reign of the dinosaurs, which continues to this day in the form of their avian descendents.
It is certain that the debate over dinosaur energetics is far from resolved, but this study definitely adds a fascinating piece to the puzzle.
Pontzer, H., Allen, V., & Hutchinson, J. (2009). Biomechanics of Running Indicates Endothermy in Bipedal Dinosaurs PLoS ONE, 4 (11) DOI: 10.1371/journal.pone.0007783
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Pontzer, H., Allen, V., & Hutchinson, J. (2009) Biomechanics of Running Indicates Endothermy in Bipedal Dinosaurs. PLoS ONE, 4(11). DOI: 10.1371/journal.pone.0007783

March 6, 2011
09:16 AM
688 views

Woolly Bats Use a Carnivorous Roost

by Anne-Marie Hodge in Endless Forms

Although many people tend to think of nature as being "red in tooth and claw," with different species constantly at odds with one another in a scramble for survival, ecological communities are actually bursting with mutualistic relationships in which species...... Read more »

Grafe, T., Schoner, C., Kerth, G., Junaidi, A., & Schoner, M. (2011) A novel resource-service mutualism between bats and pitcher plants. Biology Letters. DOI: 10.1098/rsbl.2010.1141

March 31, 2011
12:06 PM
623 views

Updated Heights of Immensity for Arctotherium: New Record for Largest Known Bear

by Anne-Marie Hodge in Endless Forms

South America is currently home to a single species of ursid, the highly elusive and uniquely patterned spectacled bear ( Tremarctos ornatus ). This species is slightly diminutive in size compared to other bears, and is known for being fairly...... Read more »

LEOPOLDO H. SOIBELZON AND BLAINE W. SCHUBERT. (2011) THE LARGEST KNOWN BEAR, ARCTOTHERIUM ANGUSTIDENS, FROM THE EARLY PLEISTOCENE PAMPEAN REGION OF ARGENTINA: WITH A DISCUSSION OF SIZE AND DIET TRENDS IN BEARS. Journal of Paleontology, 85(1), 69-75. info:/10.1666/10-037.1

June 23, 2011
06:45 PM
603 views

Brown Long-Eared Bat Rediscovered on Isles of Scilly

by Anne-Marie Hodge in Endless Forms

What is better than catching an animal that belongs to a species thought to have been extirpated for half a century? Discovering that the animal is a pregnant female, of course. With species going extinct at unprecedented rates across the...... Read more »

Eklof, J. (2003) Use of vision in prey detection by brown long-eared bats, Plecotus auritus. Animal Behaviour, 66(5), 949-953. DOI: 10.1006/anbe.2003.2272

Ecology / Conservation

March 1, 2010
08:27 PM
572 views

Fossil Snake Snacks on Sauropods

by Anne-Marie Hodge in Endless Forms

The patchy and elusive nature of the fossil record offers us limited glimpses as to what life was like during ancient times. Often, details of behavior and interspecific interactions are left open to interpretation and speculation. But occasionally, a sudden catastrophe caught ancient animals by surprise, killing and preserving them in a moment of activity. This is rather unfortunate at the time, but proves a boon to inquisitive hominds all these years later. This is exactly the case a newly described snake, Sanajeh indicus. A new paper by Wilson et al. in PLoS Biology describes remains of a few unlucky Sanajeh that were fossilized in the act of raiding a Megaloolithus (sauropod) nest, preserved forever entwined amongst the eggs and hatchlings.
Some of the most celebrated fossils are those that preserve interspecies interactions. For example, the fighting dinosaur fossil consists of a Velociraptor and Protoceratops locked in what appears to be mortal combat. There are also “food chain” fossils, such as Repenomamus, the Cretaceous mammal that wowed the world by proving that mammals were not entirely subordinate to dinosaurs during the Mesozoic: the badger-sized animal was discovered with the remains of a baby Psittacosaurus in its stomach.
And now we have Sanajeh indicus. This amazing fossil features a 3.5 m long snake, which was found in the Lameta Formation. This Late Cretaceous fossil bed near Dholi Dungri, in western India has long been a fantastic source of preserved dinosaur eggs and nests. The Lameta Formation continues to yield incredible fossils that give insight into both intra- and interspecific interactions that took place on these nesting grounds.
As shown below, the snake is curled around a crushed titanosaur egg, and lies adjacent to a recent hatchling.

It gets better. The same site yielded multiple examples of these snakes lurking around Megaloolithus nests, indicating that this was a common interaction, and that the snakes posed significant risks to sauropod offspring.
In addition to giving insights into the Cretaceous food web, these finds are also have intriguing implications for our understanding of snake phylogeny and evolution. Snakes are thought to have arisen around 98 million years ago, towards the tail end of the dinosaur’s epic reign. Modern snakes are notorious for their expandable gapes, which allow them to consume prey items that are sometimes shockingly disproportionate to their head/body size. Snakes with these abilities, referred to as macrostomatans, are thought to be derived from more basal forms that had relatively constrained jaw capacity.
As is typical of many phylogenies, however, there is much controversy over the evolutionary path that snakes have taken, especially regarding the transition from narrow- to wide-gaped morphology. Wilson et al. show that Sanajeh was indeed a “gape limited” species relative to modern macrostomatans, but that it, along with two Australian genera (see below), was “phylogenetically intermediate between the narrow-gaped aniloids and the wide-gaped macrostomatans” (emphasis added). The authors suggest that early snakes compensated for their rather conventional jaws with large body size, allowing them to consume large prey (such as titanosaur eggs) without the need to unhinge their jaws as modern snakes do. It appears that they did have some degree of intraoral kinesis, similar to that found in modern snakes, yet did not have the “unhinging” abilities that wow us today.
Sanajeh’s intermediate cranial configuration places it as a sister taxon to two late Cenozoic snakes from Australia, Wonambi and Yurlunggu. This is fascinating, as it also appears to help sort out group of species several other large snakes from ancient South America, Africa, and Madagascar, which have previously been lumped together with Wonambi and Yurlunggu due to similarities in vertebral structure. Wilson et al. designate two South American genera, Dinilysia and Najash, as basal and not closely related to the Australian snakes.

The implications of this paper span a wide range of fascinating areas, from giving insights into food web structure to helping clear up some of the enigmas of snake phylogeny and evolution. This fossil is sure to stir excitment, and the paper is definitely a must-read.

Wilson JA, Mohabey DM, Peters SE, Head JJ (2010). Predation upon hatchling dinosaurs by a new snake from the Late Cretaceous of India. PLoS Biology, 8 (3) : 10.1371/journal.pbio.1000322
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Wilson JA, Mohabey DM, Peters SE, Head JJ. (2010) Predation upon hatchling dinosaurs by a new snake from the Late Cretaceous of India. PLoS Biology, 8(3). info:/10.1371/journal.pbio.1000322

June 6, 2010
05:48 PM
548 views

Of Bears, Berries, and Hoofed Invaders

by Anne-Marie Hodge in Endless Forms

There are few images more fearsome than that of an angry bear, with teeth bared and claws flashing. It is intriguing, then, to consider a community in which a population of mighty ursids was driven to extinction by a diminutive...... Read more »

COTE, S. (2005) Extirpation of a Large Black Bear Population by Introduced White-Tailed Deer. Conservation Biology, 19(5), 1668-1671. DOI: 10.1111/j.1523-1739.2005.00252.x

January 19, 2010
01:55 PM
546 views

Crown Jewel of Biodiversity on the Edge

by Anne-Marie Hodge in Endless Forms

This week, PLoS has a new paper which reports the conservation significance of a truly astounding region in Ecuador. (Ecuador also happens to be the country in which I am conducting my thesis research, although my work is at a higher elevation in the eastern Andean foothills). The new paper by Bass et al. focuses on the Yasuni National Park, which is situated in a biodiversity hotspot, in the area where the eastern Andes foothills meet the western Amazon rainforest. It was declared a World Biosphere Reserve and Cultural Heritage by UNESCO in 1989. The park covers close to 10,000 square km, and is also home to two of South America’s few remaining indigenous tribes that live in virtual isolation from the modern world, the Tagaeri and Taromenane.

It is hard to emphasize how diverse this area is. Bass et al. have done exhaustive analysis to document the species richness, concentrations of threatened species, endemism, and ecosystem services represented within this park. They show that Yasuni is #1 in species richness for not for the country, or the continent, but the entire world for vascular plants, amphibians, birds, AND mammals. The area in which maximum species diversity for each of these groups overlaps, a kind of quadruple bang of maximum diversity, is tiny: it comprises just 0.5% of the Amazon Basin and a mere 0.16% of South America. Fish and herp species richness is also extremely high. See the paper for the many impressive facts and figures, here I will just say that this kind of richness is truly unmatched anywhere else in the world.
Not only is the Yasuni lush with diversity, but it serves as a sanctuary for many species facing extinction. Currently 13 vertebrate and 56 plant species classified by the IUCN as Critically Endangered, Endangered, or Vulnerable are found there, along with another 15 vertebrates and 47 plants classified as Near Threatened—meaning it is probably not long before they decline into more endangered status as well. There are 20 endemic amphibians, 19 endemic birds, and 4 endemic mammals (Yasuni round-eared bat, streaked dwarf porcupine, golden-mantled tamarin, and equatorial saki).

This place is also a hotspot for threatened mammals, which are the subject of my personal research interests and experience. Yasuni’s cast of characters features 8 mammal species of critical conservation concern: the white-bellied spider monkey, the giant otter, Amazonian manatee, lowland tapir, Poepigg’s woolly monkey, giant armadillo, oncilla and Melissa’s yellow-eared bat. Among the Near Threatened mammals, many of which are facing precipitous declines every year, are the golden-mantled tamarin, margay (the focal mammal of my thesis), jaguar, short-eared dog, bush dog, giant anteater, white-lipped peccary, spectral bat, and Tschudi’s yellow-shouldered bat. Obviously, Yasuni is home to a huge concentration of species which are clinging to existence.
Yasuni also serves to connect unprotected yet thus far intact habitats surrounding its borders, acting as both a sink and a corridor for biodiversity.
In a nutshell, this spectacular area has floored many scientists and experts, with the likes of E.O. Wilson and Jane Goodall referring to it as “the most biodiverse place on earth.”
Unfortunately, there is a “but” in this story. This area is incredible, but the northwestern portion of Yasuni sits atop three major oil fields—Ishpingo, Tambococha, Tiputini—collectively known as the ITT. They contain enough oil to release 410 million metric tons of CO2 into the atmosphere, not to mention the catastrophic effects of such intense habitat destruction. It has been estimated that exploitation of these oil fields could yield up to $7-10 billion for the Ecuadorian government (the American dollar is the standard currency in Ecuador). Although a June 2007 decision by president Manuel Correa established a hold on drilling expeditions in the ITT, it is still not been extended “untouchable” status, as was done for another region in the southern part of the Yasuni and another just north of the reserve, in Cuyabeno. Correa also wanted $530 million from the international community in order to keep drilling at bay. It has also been calculated, however, that the ultimate value of NOT releasing that carbon dioxide is worth $11.9 million (see a presentation on the ITT Initative’s goals and predictions here). Obviously it is in everyone’s best interests to leave the oil in the ground, if only the world were so simple. The benefits, both economic and otherwise, are nowhere near as concrete as the fast cashflow that would result from extracting the oil.
The ITT-Initiative proposes to sell carbon bonds in order to fund this deal and keep the area protected for at least the next decade, in addition to encouraging more sustainable forms of energy use in order to decrease the thirst for oil in both the near and long-term future. In addition, conservation organizations around the globe have been putting forth efforts to raise donations to preserve the site and fund alternative energy projects in the region. The ITT-Initiative program would provide Ecuador with the opportunity to change its energy matrix and infrastructure, while establishing itself as a poster child for commitment to conservation and progressive, cleaner forms of development.
It all sounds very encouraging, but situations like this are tenuously subject to the whims of leaders, governments, native peoples, pressure from surrounding nations, and climactic circumstance. The vulnerability of this agreement is that at any moment, Ecuador can repay the international loan that “reserves the reserve” and proceed to drill it into oblivion. It can only be hoped that Bass et al.‘s exhaustive study and analysis of the biodiversity and ecosystem services provided by the Yasuni will help in efforts to keep this region from being destroyed in order to provide a short-term fix for the world’s oil addiction.
Although the Yasuni has been granted a reprieve for now, it is crucial to not become overconfident when it comes to dealing with conservation agreements in developing nations (or developed nations, for that matter, the US does not have a stellar record itself). The park should still be considered—like so many of the organisms that currently seek refuge there—as being very much on the edge.

Bass, M., Finer, M., Jenkins, C., Kreft, H., Cisneros-Heredia, D., McCracken, S., Pitman, N., English, P., Swing, K., Villa, G., Di Fiore, A., Voigt, C., & Kunz, T. (2010). Global Conservation Significance of Ecuador’s Yasuní National Park PLoS ONE, 5 (1) DOI: 10.1371/journal.pone.0008767
Image 1 source
Image 2 source
Image 3 source
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Bass, M., Finer, M., Jenkins, C., Kreft, H., Cisneros-Heredia, D., McCracken, S., Pitman, N., English, P., Swing, K., Villa, G.... (2010) Global Conservation Significance of Ecuador's Yasuní National Park. PLoS ONE, 5(1). DOI: 10.1371/journal.pone.0008767

Biology

July 14, 2011
07:09 PM
531 views

Polar Bears Have a Touch of the Irish

by Anne-Marie Hodge in Endless Forms

One cannot always judge a species by its cover. For example, grizzly and polar bears are in no danger of being mistaken for one another morphologically, and yet molecular studies have shown that the polar bear is actually nested within...... Read more »

Edwards, C., Suchard, M., Lemey, P., Welch, J., Barnes, I., Fulton, T., Barnett, R., O'Connell, T., Coxon, P., Monaghan, N.... (2011) Ancient Hybridization and an Irish Origin for the Modern Polar Bear Matriline. Current Biology. DOI: 10.1016/j.cub.2011.05.058

April 28, 2010
08:05 PM
529 views

Saving face: Salamanders show why it's important to know thy enemies

by Anne-Marie Hodge in Endless Forms

In the past I have focused on reviewing newly published literature, but I have decided to periodically take a look back at some "classic" zoology papers. Defining "classic" is difficult, I am using the slightly arbitrary criteria that the paper...... Read more »

Jaeger, R. (1981) Dear Enemy Recognition and the Costs of Aggression between Salamanders. The American Naturalist, 117(6), 962. DOI: 10.1086/283780

May 2, 2010
06:42 PM
523 views

Boozing Treeshrews: Heavyweight drinkers in small packages

by Anne-Marie Hodge in Endless Forms

Although political and moral stances on alcohol use have gone back and forth over the decades, anthropological studies suggest that low-level alcohol ingestion has been an important factor in primate evolution. Alcohol is associated with ripe, nutrient-rich fruits, in addition...... Read more »

Wiens, F., Zitzmann, A., Lachance, M., Yegles, M., Pragst, F., Wurst, F., von Holst, D., Guan, S., & Spanagel, R. (2008) Chronic intake of fermented floral nectar by wild treeshrews. Proceedings of the National Academy of Sciences, 105(30), 10426-10431. DOI: 10.1073/pnas.0801628105

August 18, 2011
04:14 PM
519 views

Contagious Cancer, Beyond the Devils

by Anne-Marie Hodge in Endless Forms

Few health issues strike a deeper chord of fear than that of cancer--your own body's tissues being hijacked, turning against you and taking over. An estimated 1,596,670 new cancer cases (not including some types of skin cancer, which are not...... Read more »

Rebbeck, C., Thomas, R., Breen, M., Leroi, A., & Burt, A. (2009) ORIGINS AND EVOLUTION OF A TRANSMISSIBLE CANCER. Evolution, 63(9), 2340-2349. DOI: 10.1111/j.1558-5646.2009.00724.x

March 3, 2010
10:55 AM
483 views

Radar Deterrents Save Bats

by Anne-Marie Hodge in Endless Forms

Harvesting wind power is a fast-growing form of alternative energy technology, and U.S. interest in the wind industry is growing, as we work towards diversifying our energy grid. New turbines are being erected across the nation, and the prospects for...... Read more »

Nicholls, B., & Racey, P. (2009) The Aversive Effect of Electromagnetic Radiation on Foraging Bats—A Possible Means of Discouraging Bats from Approaching Wind Turbines. PLoS ONE, 4(7). DOI: 10.1371/journal.pone.0006246

Biology

January 20, 2011
11:30 AM
430 views

Allee Effects, Round Two: Component versus Demographic Effects

by Anne-Marie Hodge in Endless Forms

In my last post, we discussed Allee effects and the importance of taking those factors into consideration when making plans for managing threatened species. This time, I'm going to pick the Allee effect apart just a little bit more. Much...... Read more »

ANGULO, E., ROEMER, G., BEREC, L., GASCOIGNE, J., & COURCHAMP, F. (2007) Double Allee Effects and Extinction in the Island Fox. Conservation Biology, 21(4), 1082-1091. DOI: 10.1111/j.1523-1739.2007.00721.x

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