Eastern hemlock, a keystone species in the streamside forests in the southern Appalachian region, is already experiencing widespread decline and mortality and may be decimated by the hemlock woolly adelgid (a tiny nonnative insect) within the next 10 years. As a native evergreen capable of maintaining year-round transpiration rates, eastern hemlock plays an important role in the ecology and hydrology of mountain ecosystems. Hemlocks provide critical habitat for birds and other animals; their shade helps maintain the cool water temperatures required by trout and other aquatic organisms in mountain streams.
"No other native evergreen in the southern Appalachians will likely fill the ecohydrological role of eastern hemlock if widespread mortality occurs," says Ford, ecologist with the Otto, NC unit where Vose is project leader. "With the loss of this species, we predict changes to streamflow, streamside forest structure, and soil moisture that will have to be addressed by land managers."
Hemlock woolly adelgids attach themselves to the base of the needles of the eastern hemlock, feeding on carbon fixed by the trees, slowing growth and causing the needles to drop. Needle loss causes the crown of the tree to thin and dieback in branches; in a surprisingly short time - usually 5 to 10 years - the tree fades away and dies.
To estimate the impact the loss of hemlock will have on the water balance, the researchers measured transpiration rates over a range of tree sizes for 2 years. "We found quite substantial transpiration rates for individual hemlocks, with large trees transpiring as much as 49 gallons of water a day." says Ford.
The study showed that eastern hemlock plays two distinct ecohydrological roles in the southern Appalachian region: one as an evergreen tree with relatively stable water use throughout the year; the other as a streamside tree with high rates of water use in the spring. If hemlock is lost, there is probably no other native tree species that can fill these roles.
"As hemlock woolly adelgid infestations increase, we expect to see at least short term reductions in forest transpiration rates," says Ford. "For southern Appalachian forests specifically, we estimate that eastern hemlock mortality could reduce annual forest transpiration by 10 percent, and winter and spring transpiration by 30 percent. We expect this will increase soil moisture and alter both the amount and timing of stream flow. The duration of these changes will depend on how other vegetation responds to the loss of hemlock."
Read the full text of the article at http://www.esajournals.org/perlserv/?request=get-document&doi=10.1890%2F06-0027
Chelcy Ford | EurekAlert!
Dune ecosystem modelling
26.06.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
Understanding animal social networks can aid wildlife conservation
23.06.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
26.06.2017 | Life Sciences
26.06.2017 | Physics and Astronomy
26.06.2017 | Information Technology