Duck broods are more resilient than expected in the face of oil and natural gas extraction
Kemink, K. M., Gue, C. T., Loesch, C. R., Cressey, R. L., Sieges, M. L., & Szymanski, M. L. (2019). Impacts of Oil and Gas Development on Duck Brood Abundance. The Journal of Wildlife Management, 83(7), 1485–1494. https://doi.org/10.1002/jwmg.21742
Featured Image: Paula, Flickr.com
The Bakken Formation: A mecca for waterfowl and fossil fuels
The Bakken Formation is a region in North Dakota and northeast Montana that is rich in oil and natural gas. Over the last couple of decades, extraction of these resources has increased. The region is also home to many wetland and grassland areas that are protected as habitat for waterfowl.
Waterfowl conservation occurs through a landscape approach to habitat conservation. Instead of just focusing on the ducks themselves, managers work on protecting small parcels of their habitat via conservation easements, which are agreements between a landowner and nonprofit or government agency to limit the use of land to protect its conservation value.
What we know, and what we don’t
Previous research and models have shown that waterfowl populations are healthiest in landscapes that are full of small, shallow wetlands. However, is the increase in oil and gas production affecting the health and conservation value of waterfowl habitats? Scientists from Ducks Unlimited wanted to find out.
Past research has shown that some birds, such as the greater sage grouse and grassland songbirds, avoid developed areas. Scientists aren’t sure exactly why birds avoid development, but possible factors include loud noise, more habitat availability and travel corridors for predators, new tall buildings, and direct harm from collisions or toxins.
Science is still unclear on the effects of development on ducks, and managers need this research to identify areas that should be protected.
Testing a hypothesis
Scientists hypothesized that abundance of duck broods (families of babies produced from one hatching), would decrease as natural gas and oil extraction increased.
To test this hypothesis, the researchers identified oil well location then selected sampling plots that were varying distances from these oil wells but had similar ecological conditions (percent cover of grassland, and temporary, seasonal, or semi-permanent wetlands) so that they could be directly compared. Plots were surveyed during two periods per year, from 2014 to 2017, and each plot was surveyed twice within a surveying period. Observers walked through the entire sampling plot and used binoculars to identify and count broods. They surveyed 25 plots in 2014, 64 in 2015, 71 in2016, and 67 in 2017. Differences in numbers from year to year occurred because of varying environmental conditions and accessibility.
Disturbance from oil and gas development was characterized by using the presence of roads, oil well pads, and gravel pits. Results showed that there was only a very small decrease in brood abundance in response to disturbance.
Results, implications, and what comes next
The amount of wetland area was the main factor influencing brood size. A greater number of wetlands over a landscape area was correlated with greater brood sizes. Based on this study, managers should prioritize wetland conservation regardless of whether there is oil or natural gas extraction occurring nearby- these are not “lost” habitats, and can still be valuable for ducks even though they are experiencing more development.
Although this landscape-level study doesn’t show a strong negative relationship, effects may accumulate over time from small local scales. Oil and gas extraction may lead to contamination of water, causing direct harm to waterfowl in some cases. Development may also lead to losses of invertebrate diversity, which are crucial as a food source for breeding waterfowl. Future localized research is needed to determine whether patterns could be identified at a smaller scale.