Tag Archives: fauna

mountain fauna

Mid-altitude biodiversity most influenced by topography, but why is this important?

In a mountainous setting, you’ll find the most species somewhere around mid-altitude. The consensus is that further up there is less oxygen and the temperature is lower, while further down factors like human disturbance hinders diversity. Swiss researchers who thoroughly modeled biodiversity in a terrain that actually mimics a mountain, not an ideal cone or hill, found a different explanation which seems to be more important that temperature, humidity or anything else. It’s all about the topography of the terrain, and whether or not it allows for niches to become connected. The findings could prove extremely important in gauging the future impact of migrating species to higher elevation as a result of climate change.

mountain fauna

Photo: Chamonix.net

In a patch of land, the number of species that can live in harmony, let’s say, depends on a number of factors. For instance, a large area will most often than not host many more species than a smaller area though the conditions may be the same. Keeping this in mind, researchers from the Institute of Evolutionary Biology and Environmental Studies at the University of Zurich transposed what we know about biodiversity in the flatlands to the mountainous terrain.

“In mountainous terrain, peaks and valleys are isolated habitats, like islands in the ocean, whereas mid-elevation sites form well-connected patches,” explains Enrico Bertuzzo, a researcher at the Ecohydrology Lab at EPFL and first author of the study. “Given that habitat area and connectivity foster biodiversity, whereas isolation favors the dominance of few species, we hypothesized that topography itself could be playing a key role in regulating how biodiversity varies with elevation.”

Previously, these sort of studies were modeled on ideal surfaces, like a cone. These, however, failed to grasp the richness and complexity of an actual mountainous terrain. Bertuzzo and colleagues painstakingly considered all its complexity, then set loose hordes of virtual species in a computer simulation. Each species had an optimal altitude where it thrived, When the researchers let the virtual species compete for habitats on landscapes modeled on real-life ones, their simulations showed that topography alone was enough to explain biodiversity patterns observed in nature. “Other factors, like temperature, productivity, etc., are obviously also important, but they inevitably act on top of the unavoidable effect provided by the landscape structure,” the researchers note in  Proceedings of the National Academy of Science. 

The findings are very important given today’s context. As the planet heats, many species — both animals and plants — will migrate to a cooler habitat, which can be further north or south of their current position or at a more elevated altitude. But what will they find there? At mid-altitude, more competition if the terrain allows it, i.e. no peaks or valleys. It’s not important for migration models to take the present findings into account.

“Local species richness is found to be related to the landscape elevational connectivity, as quantified by a newly proposed metric that applies tools of complex network theory to measure the closeness of a site to others with similar habitat. Our theoretical results suggest clear geomorphic controls on elevational gradients of species richness and support the use of the landscape elevational connectivity as a null model for the analysis of the distribution of biodiversity,” the conclusion in the study’ abstract reads.

wildlife_fences

Fences threaten local fauna, instead of protecting it

wildlife_fences

Photo: conservationafrica.net

In some parts of the world you can find fences that stretch for hundreds of miles, delimiting protected areas or those populated with humans. The basic reasoning is that these fences are put in place to protect the local wildlife by preventing the spread of diseases, poachers and by helping helping managed endangered populations. The reverse may actually be true, according to a study published in the journal Science.

Livestock and wildlife don’t mix well, so farms and local governments have established  extensive fencing systems to ward of contact between the two and stop diseases like foot and mouth from spreading. These sort of fences, hundreds of miles long, are particularly common in South Africa. Researchers at Zoological Society of London report, however, that the effects produced are actually counter-intuitive.

The fences disrupt predator prey dynamics, such as the case of African wild dogs who have learned to chase they prey into fences where they become cornered. Fences also limit herds from grazing grounds, as elephants and wildebeest are now unable to reach the vast areas of land they require to support their population.

Fences may cause an ecological meltdown

A lot of people promoting the use of fences advocate that the most and foremost, these need to be put in place to separate human civilization from wildlife, which actually gathers local support for one reason or another. The study notes, however, that these aren’t that practical and most situations. After studying 37 fences in Southern India, researchers found that almost 50 percent failed to prevent the passage of elephants, demonstrating the difficulty in designing and maintaining fences.

“In some parts of the world, fencing is part of the culture of wildlife conservation – it’s assumed that all wildlife areas have to be fenced. But fencing profoundly alters ecosystems, and can cause some species to disappear,” said Rosie Woodroffe, lead author of the study.

It’s a bit naive to think that fences keep poachers out. Ironically, many fences come as a ready supply of wire for making snares.

The scientists involved in the study advise that a better design and implementation of fencing is warranted, and only in areas where these are necessary.

“An increased awareness of the damage caused by fencing is leading to movements to remove fences instead of building more. Increasingly, fencing is seen as backwards step in conservation,” concluded study co-author Sarah Durant, also of the Zoological Society.

 

VICKSBURG, MS - MAY 10: A home is surrounded by floodwater May 10, 2011 in Vicksburg, MS. (Scott Olson - GETTY IMAGES)

Mississippi flood leads to hoards of animal refugees

VICKSBURG, MS - MAY 10: A home is surrounded by floodwater May 10, 2011 in Vicksburg, MS. (Scott Olson - GETTY IMAGES)

VICKSBURG, MS – MAY 10: A home is surrounded by floodwater May 10, 2011 in Vicksburg, MS.

Late this Monday, the Mississippi crested in at 47.8 feet (14.5 meters), just less than a foot below the city’s record, set in 1937. As the river reaches nearby city neighborhoods and Shelby County suburbs, nature has “put the pin back in the grenade,” said county spokesperson Steve Shular.

Floods are really nasty, but for the local fauna everything’s gone for a turn to the worst, as the waters are forcing them to leave their natural habitat and look for shelter elsewhere – some less lucky get drowned in the process.

“We’re starting to see some issues, especially with the snakes,” Shular explained. “We’ve definitely seen a lot of snakes, like water moccasins [picture]”—venomous pit vipers with potentially fatal bites that are also called.

Yes, those are venomous pit vipers (commonly know as cottonmouths) which could potentially fatally bit a person, and as swollen rivers start reaching up near homes and neighborhoods, things start going really crazy.

“We want to make sure people understand that the rules have changed,” Shular said.

“When that water gets into a neighborhood, snakes are going to be searching for shelter and food in homes or sheds or wherever they can slither into.”

Poisonous snakes exodus

The sudden influx of snakes in residential ares could prove to be devastating for the already thinning number of snakes in the Mississippi area, simply because people kill them on sight usually when they see them in their backyards.

It’s not just snakes either, countless rabbits, turkeys, deer, and other animals have been forced to flee—or perish.

“We’ve seen photos of herds of deer on levees trying to get away from the waters and heard from the Army Corps of Engineers that they’ve seen deer drowned during the flood,” according to Tennessee Wildlife Resources Agency officer Jereme Odom.

“One of our wildlife managers even spotted deer and coyotes”—natural enemies—”standing on the same levee together,” he said.

While most animals will survive the Mississippi River flood, for some their habitats could take years to return to normal. The local wild turkey is one of the most hardly hit species by the floods in the area. The wild turkey is nesting in this time of year, and as a result many of those nests have been lost to or displaced by floods – countless new hatched birds might not survive.

“Animals will be displaced for so long that, when the water does recede, it will take a while to get back to their original habitats,” he said. “Some may be established elsewhere or displaced so far away that they never get back.”

Neighboring residents are advised to wait for Mississippi levels to decrease

The Tennessee Wildlife Resources Agency is advising people, whenever possible, to simply wait for animals to return to their normal habitats. Floods come and go, and eventually the Mississippi water level should dampen.

“Animals that appear to be in need of rescue should be left alone,” Chad Harden, a big game coordinator with the agency, said in a May 6 statement.

“They are under stress, but their natural survival instincts will help them cope with the situation until things get back to normal. The animals could pose a real danger to someone who might try to rescue them.”

For his part, Tennessee wildlife officer Odom is taking the long view.

“This isn’t the first time we’ve seen major floods. It goes all the way back to Noah, and the animals are still here,” he said. “The main thing is what humans will do to let them come back.”

Story via National Geographic