A September study looked at more than 40,000 moose habitats across Vermont to see how informed wildlife management can make life better for moose, even as winter ticks take over.
Researchers from Vermont Fish & Wildlife and the University of Vermont’s Rubenstein School of Environment and Natural Resources have been studying different aspects of moose populations during the past three years, and this study focused on habitat.
Moose have always had winter ticks on them — the species evolved together — but they’ve become a much bigger problem in the past 20 years, the result of climate change bringing shorter winters, less snow and warmer summers. The ticks now hold an advantage over moose in places where they survive better and breed more.
“Kind of similar to how Covid behaves in society — if there’s more people, there’s likely higher rates of Covid. It’s the same sort of thing with moose,” said Katherina Gieder, the biometrician and research manager for Vermont Fish & Wildlife and a co-author of the study. “If there’s higher density of moose and they concentrate, then you see higher densities of winter ticks, and then you see more and more negative effects of ticks to the point where it’s affecting the population.”
That’s particularly a problem in the Northeast Kingdom. Gieder said about 3,000 moose lived in Vermont last year — and 2,000 of them were in the Northeast Kingdom.
The Northeast Kingdom now averages 1.5 moose per square mile, Gieder said, and wildlife experts hope to get that number below 0.75 — still triple the 0.25 moose density per square mile in the rest of the state, but low enough to bring down the number of winter ticks.
“The tick numbers are going up and anytime that happens, if there are a lot of moose on the landscape, they’re going to get on the moose and then the situation is going to be exponentially exacerbated,” Gieder said.
The study data shows potential “hotspots” for moose that wildlife management can use when considering the spatial distribution of ideal moose habitats, as well as what type of forest composition moose prefer.
Researchers were able to track how moose of different ages and gender groups use habitat differently. They found that female moose use younger forests as well as more mature forests, while males prefer higher elevations and more mixed forest types.
“So if you’re cutting a forest patch, it really matters where you’re cutting that because it might not benefit moose equally across the board,” Gieder said.
To Gieder, the most surprising finding was that females who had calves that survived used really different habitats from female moose whose calves were killed by excess ticks.
Wildlife managers can use that information to look at where female moose calves are surviving, and promote that type of habitat, in hopes of boosting the overall moose population.
“Habitat use by moose is far from simple, so when you’re talking about managing habitat for moose, it can’t really occur on a level of, well, let’s just do a forest cut here,” Gieder said. “It’s a much more complex relationship than that.”
Gieder said the September study is just the tip of the iceberg for moose habitats, and just one portion of the complex wildlife issues related to climate change.
