Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fragmentation may be linked to local amphibian extinctions

25.09.2002


Habitat fragmentation is a primary threat to amphibians worldwide, and new research suggests one of the reasons why. Experimental evidence for three species shows that fragmentation may hinder the dispersal of juvenile amphibians, which could contribute to population declines.



"Habitat fragmentation is likely to reduce dispersal rates between local populations of these three species," say Betsie Rothermel and Raymond Semlitsch of the University of Missouri in Columbia in the October issue of Conservation Biology.

Dispersal of juvenile amphibians is critical to maintaining populations of pond-breeding species. Local populations of these amphibians naturally die out frequently but are replenished by juveniles from other ponds (adults rarely switch breeding sites). "Interpond dispersal is the means by which declining populations may be rescued or recolonized following extinction," say the researchers. However, little is known about how habitat disturbance affects the dispersal of juvenile amphibians.


Rothermel and Semlitsch studied the movements of three types of juvenile amphibians (spotted salamander, small-mouthed salamander and American toad) in the 127-ha C.W. Green Conservation Area in Boone County, Missouri. In the midwestern U.S., much of the land around amphibian breeding sites has been converted from forest to cropland or pasture. The researchers collected amphibian eggs in the wild, raised them in tanks, transferred the larvae to artificial pools on the edges between forest and old fields, and then studied their movements during the first two months after metamorphosis.

While small-mouthed salamanders showed no preference for forest or old field, the researchers found that the other two species studied moved farther into the forest than into old fields. Spotted salamanders moved almost eight times farther and toads moved more than three times farther (spotted salamanders moved 43 vs. 5 feet in the forest and old field, respectively; the toads moved 108 vs. 33 feet, respectively).

The juvenile toads’ preference for the forest came as a surprise because the species is ubiquitous, occurring in natural and disturbed habitats alike. The fact that the juvenile toads avoided the open field shows that juvenile behavior cannot be predicted based on adult behavior, say the researchers.

Rothermel and Semlitsch suggest that moving through fields would make the juvenile amphibians more vulnerable to predators or desiccation. They compared how fast juvenile salamanders desiccated in the forest and in the field, and found that in a 24-hour period they lost about a third more water in the field (6% vs. 4.5% of their body weight in the field and forest, respectively). This is not surprising because the maximum temperatures were roughly 10 degrees Celsius higher in field than in forest.

Rothermel concludes that conserving amphibian populations in highly fragmented forests may require connecting their habitat patches. "The results of this study suggest that juvenile amphibians might preferentially use corridors of natural vegetation," she says.

ADDITIONAL CONTACT INFORMATION:
*Raymond Semlitsch (573-884-6396, semlitschr@missouri.edu)

Betsie Rothermel | EurekAlert!
Further information:
http://www.biosci.missouri.edu/semlitsch/index.html
http://nasw.org/users/rmeadows
http://conservationbiology.org/

More articles from Ecology, The Environment and Conservation:

nachricht A new indicator for marine ecosystem changes: the diatom/dinoflagellate index
21.08.2017 | Leibniz-Institut für Ostseeforschung Warnemünde

nachricht Value from wastewater
16.08.2017 | Hochschule Landshut

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Nagoya physicists resolve long-standing mystery of structure-less transition

21.08.2017 | Materials Sciences

Chronic stress induces fatal organ dysfunctions via a new neural circuit

21.08.2017 | Health and Medicine

Scientists from the MSU studied new liquid-crystalline photochrom

21.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>