How Energy Developments Affect the Migration of Deers During Spring

The current study demonstrates how growth disturbs deer movements, causing deer to lose their ability to coordinate their foraging with the wave of the most nutrient-dense springtime plants.

Energy development holds up deer during spring migration

(Photo : George Frey/Getty Images)

That is, in effect, the latest discovery of a US-led collaborative investigation. The United States Geological Survey (USGS) and the University of Wyoming calculated how much feed mule deer miss when energy development affects their travel paths, as per ScienceDaily.

Mule deer are recognized for their ability to perfectly time their movements with spring green-up, so this finding was especially surprising, said to lead author Ellen Aikens, a UW Ph.D. graduate who now works for the USGS South Dakota Cooperative Fish and Wildlife Research Unit. The gas wells forced them to miss out on the tastiest meals of the year.

The study, titled "Industrial energy development decouples ungulate migration from the green wave," was published today (Thursday) in the prestigious academic journal Nature Ecology & Evolution.

Mule deer travel to the American West each spring to follow the greening of flora as they grow at various elevations.

Mule deer rely on this surfing behavior to pick the youngest and most nutritious plants, allowing them to recuperate from winter and build on fat for the following lean season, according to biologists.

The present study, on the other hand, demonstrates how growth interrupts deer movements, causing deer to lose their ability to coordinate their foraging with the wave of the most nutritious springtime plants.

The 14-year research followed a migratory mule deer herd that spends the winters in sagebrush basins and the summers in the Sierra Madre Mountains, approximately 15 miles southwest of Rawlins.

During the research period, hundreds of additional wells for coalbed methane extraction were dug in the heart of an established mule deer corridor.

The long-term mobility data enabled a comparison of the impact of growing development on mule deer migration.

A previous study by the researchers described how mule deer behavior changed in reaction to the new gas wells, forcing animals to reroute, rush through the good pads, and pause less to graze.

The researchers evaluated deer movements for the current study, as well as daily variations in spring green-up estimated from distant satellite data, to determine how successfully the deer surfed around the corridor, upstream and downstream from the energy development, and over a 14-year period.

The deer began to "hold up" when they approached the natural gas wells as development intensity rose over time.

They delayed their spring migration and let the wave of green foliage pass them by, becoming disconnected from their richest food supplies at a critical time of year.

There was no indication that mule deer were used to increase human presence, truck traffic, and noise. Green-wave surfing behavior was influenced to a similar extent by little and large-scale changes.

The research will assist wildlife managers in understanding how pristine corridors must be in order to maintain their biological viability.

Deer were still able to walk across the gas field in this situation, but the migration corridor's important function of tracking the green wave all the way along the path at the optimal stage of plant growth was lost.

The discovery is significant because it reduces the total advantage of migration, which is typically the most profitable strategy for ungulates as diverse as mule deer in Wyoming, caribou in the Arctic, and antelope pursuing rains across the African plains.

The study serves as a cautionary tale, demonstrating how development inside corridors can limit the advantages of migratory behavior, ultimately leading to movement loss and population losses on heavily damaged landscapes.

The researchers believe that their findings would pave the path for future mule deer migrations.

Read more: Red Deer Tend To Become Introverted as They Age According To Study

How does this research relate to other studies regarding land use and mule deer populations?

Management measures that restrict surface disturbance in core sage-grouse habitats have been critical in maintaining a vulnerable bird like the greater sage-grouse across the West and keeping it off the Endangered Species List, as per PEW.

Their research implies that a similar technique may be needed to keep mule deer migration routes effective in areas where energy production is major land use.

Land managers must balance conflicting land uses while making judgments based on poor data.

Their role is to offer information to managers and other stakeholders in order for them to better their planning and management efforts.

This research can assist guide choices about energy development and mineral leasing in locations where mule deer migration paths intersect.

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