Mule deer mothers are in sync with their environment, with reproduction patterns that closely match the cycles of plant growth in their habitat. And new research using NASA satellite data shows that tracking vegetation from space can help wildlife managers predict when does will give birth to fawns.
Raising a fawn is no easy task - a doe needs a rich supply of vegetation for the late stages of pregnancy and for nursing. Mule deer birth rates peak shortly before the peak of annual plant growth, when food sources are increasing. Through a combination of satellite measurements and ground-based population counts, researchers can forecast the timing of fawning seasons based on vegetation.
"We had never tracked the deer population this way, and we had never been able to predict it with such precision," said David Stoner of Utah State University, lead author of a recent study. "We can estimate the start and peak of the season using satellite imagery, and then we can map and predict when the deer are giving birth in any given region."
Mule deer populations are closely monitored and counted by biologists and land managers, in part to determine population trends over time, which helps them set the proper number of hunting permits to issue. At the same time, remote sensing scientists have a space-based way to track when vegetation greens up and how productive it is compared to drought or wet years. the health of vegetation
. The tool is called the Normalized Difference Vegetation Index (NDVI), which is a measure of the "greenness" of the landscape. It measures how plants absorb and reflect light -- the more infrared light is reflected, the healthier the vegetation. So by measuring the greenness of the mule deer habitat, scientists were able to mark the beginning and peak of the plant growing season - and the fawning season.
To visualize the relationship between vegetation greenness and fawns, Stoner and his colleagues divided mule deer habitat that stretched from southern Idaho to central Arizona into three zones. They measured the NDVI for each day of the calendar year, using the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on NASA's Terra and Aqua satellites.
They found that vegetation greenness in the northern latitudes peaks earlier than in the southern latitudes, according to Stoner. Since nutrient-dense food sources were available earlier in the year, there was more food available for mule deer mothers and babies at the time when they needed it most. That greenness is partly a result of a consistent stream of snowmelt moisture feeding the deep roots of mountain plants.
In southern latitudes, on the other hand, the plants are more dependent on rain from late summer monsoonal showers. This means vegetation quality peaks later in the year, after a brief drought that comes before the summer monsoons. As a result, does give birth later in the south than in the north.
"This kind of applied research is very important for making remote sensing data relevant to wildlife management efforts," said Jyoteshwar Nagol, a researcher at the University of Maryland. Deer have a huge economic impact in the United States, from hunting to crop damage to car accidents. As regional climates shift or droughts occur, deer distributions could change in response to changes in the timing of vegetation green-up.
For more information:
Earth Observatory Story:
Kate Ramsayer | EurekAlert!
NSF-supported scientists present new research results on Earth's critical zone
13.12.2018 | National Science Foundation
Megacity traffic soot contributes to global warming
13.12.2018 | Leibniz-Institut für Troposphärenforschung e. V.
What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...
A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...
A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...
What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.
Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...
12.12.2018 | Event News
10.12.2018 | Event News
06.12.2018 | Event News
13.12.2018 | Awards Funding
13.12.2018 | Earth Sciences
13.12.2018 | Materials Sciences