It is like the premise of a popular home improvement show: in the before photos, the surroundings are undesirable and in the after shot there’s lots of attractive spaces to grab a meal, start a family and relax in seclusion from life’s stresses.
The difference here is that the potential new homeowner is a lizard and the renovations come -- not from a sophisticated Manhattan designer -- but instead from a herd of elephants. An examination of the connections between elephants and lizards appears this month in the journal Ecology, where a researcher reports that the elephants’ eating habits have a strong influence on the lizards’ habitat choices. The results demonstrate an important and little understood aspect of ecosystem engineering, and may help land managers working on wildlife refuges in Africa.
Working at the Mpala Research Center in Kenya between 2004 and 2007, the author of the report, Robert M. Pringle of Stanford University, found that Kenya dwarf geckos (Lygodactylus keniensis) showed a strong preference for trees which had been damaged by browsing elephants (Loxodontia africana). In fact, the local lizard population increased proportionally with the number of damaged trees. By contrast, lizards were virtually absent from undamaged trees in the same study area.
Further investigations revealed that the preference was due to hiding places which were incidentally created by the elephants’ activities.
Pringle’s results are important from a theoretical as well as management standpoint. Ecosystem engineering -- the idea that activities of one kind of animal can create habitat for other animals -- is a relatively new concept, having emerged only about 15 years ago. When examining such engineers, ecologists would like to predict whether their activities will have a positive or negative impact on the abundance of other species in the same ecosystem. In the past, some scientists have hypothesized that when the engineers (such as the elephants in this case) make a habitat more complex, that habitat becomes more appealing to a larger variety of animals. This research indicates that may indeed be the case in African savannas.
Pringle notes that elephants really “shake up” the savanna landscape. The level of disturbance from a feeding herd is almost akin to that of a tornado touching down; trees and shrubs are splintered, cracked, and fissured and large branches are strewn all over the ground.
“The ripped up trees are like labyrinths compared to the pristine trees, which helps boost lizard densities,” says Pringle. This may be because the twisted crevices in the elephant-damaged trees provide shelter from predators and the harsh arid environment, or because they provide suitable spots for female lizards to lay eggs.
A better understanding of the elephants’ influence on their ecosystem is a particularly pressing need in this region. There are concerns in many parts of Africa that poaching may wipe out the large animals on lands where they are not strictly protected. Elephants, however, eat a tremendous amount, and their eating habits can be especially destructive in smaller tracts of land. Since they have no real natural predators besides humans, they can sometimes eat themselves out of house and home in the areas where they are protected from hunters.
Because of these management dilemmas, finding an “optimum number” of elephants for any given refuge or wildlife area has become a hot topic. By gaining a better understanding of ecosystem engineering and the effects that large herbivores have on other species, researchers may gain more insight into how the entire savanna ecosystem works.
“If you have no elephants,” says Pringle, “then you’re missing this powerful source of disturbance, since their activities can provide other species with a chance to thrive. On the other hand, if you have too many elephants, then they can actually suppress the abundance of smaller animals by reducing their habitat and out-competing them for food.”
Biodiversity, the researcher says, may well be greatest in the middle ranges of elephant abundance.
Nadine Lymn | EurekAlert!
From the Arctic to the tropics: researchers present a unique database on Earth’s vegetation
20.11.2018 | Martin-Luther-Universität Halle-Wittenberg
Fading stripes in Southeast Asia: First insight into the ecology of an elusive and threatened rabbit
20.11.2018 | Forschungsverbund Berlin e.V.
Max Planck researchers revel the nano-structure of molecular trains and the reason for smooth transport in cellular antennas.
Moving around, sensing the extracellular environment, and signaling to other cells are important for a cell to function properly. Responsible for those tasks...
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
19.11.2018 | Event News
09.11.2018 | Event News
06.11.2018 | Event News
20.11.2018 | Life Sciences
20.11.2018 | Life Sciences
20.11.2018 | Physics and Astronomy