THROUGH their research on the San Luis Valley wetlands and bird migration patterns, Cary Aloiaand Jenny Nehring can tell you ducks that are divers are arriving on average 1.24 days earlier in the Valley, and ducks that are dabblers 1.7 days earlier.
WHAT DOES IT MEAN?
“Means that every year the peak migration is occurring 1.5 days earlier,” said Aloia. “If we look at historic records, peak migration was end of March-ish and now we’re looking at getting close to the beginning of March. What’s significant to that is that the irrigation season starts April 1. That means that farmers aren’t putting water out on their properties, they aren’t flood irrigating when the peak number of birds are there.
“What that also means is because peak numbers are March, the beginning of March, the birds start coming in the end of January now and February, and so we’ve got this period of time where we’re really limited because of an irrigation system.”
It’s complicated, but then it isn’t. Simply, climate change – where we experience extreme weather events hot and cold, and experience an overall warming to the seasons – is having a damaging effect on the natural wildlife of the Valley, the natural lands of the Valley, and how we all use it.
Photo: Ryan Michelle Scavo
The complication enters with solutions put forth to address the changing climate and how far the Valley is willing to go to address it. Spending time with Aloia and Nehring helps in understanding the circumstances and conditions.
The Alamosa Citizen visited recently over a Zoom call with Aloia and Nehring to talk about their research and ongoing work to address the Valley’s changing environment. Aloia and Nehring are biologists who work together as Wetland Dynamics and consult with companies and governmental agencies to preserve and conserve wetlands, riparian areas, and ecosystems like the San Luis Valley.
Their study, “San Luis Valley Wetland and Wildlife Conservation Assessment” published in 2019 and updated in 2020, is in the category of must reading if you care an iota about the San Luis Valley and how it’s faring in the first decades of the 21st century as climate change makes its presence more acutely felt.
“I would say we’ve got the climate change aspect, but we’ve also got sort of this urban push into wildlife habitat and the change in not only conversion of different types of wetlands, but the complete loss of wetlands,” said Aloia. “As the assessment pointed out, we have about a third of the wetlands that we had historically, and we continue to keep pushing that envelope, converting wetlands, and part of that conversion is, of course, the drought that we’re going through. We’ve lost a lot of wetlands because the water doesn’t get where it was historically.
Now we’re getting into climate change, human migration patterns as people seek out lesser-known and less-crowded spaces, land development, and intersecting it with the natural habitats that are being impacted by it all.
Here’s how Nehring follows up her partner Aloia’s comment when she said, “‘We have an exponential number of people coming here.”’
“I was reading a book on migration this last year,” Nehring said, “and they were talking about how if you watch a warbler foraging through just trees on the bank of a river, and it’s a bird that’s migrating. Neotropical songbirds migrate at night and they land in the morning, and they’ll feed and rest through the day, and then they’ll take off and fly another stretch that night. Or maybe they’ll stay two days. And it’s very weather dependent, and they follow rivers. Rivers are huge landmarks for migrating birds, and so if you watch a warbler foraging during migration, about once every three seconds, it’ll glean a little bug off a leaf and it’s eating.
Photo credit: Ryan Michelle ScavoPhoto credit: Ryan Michelle Scavo
“And if an area is cleared of that vegetation, and maybe the bird has to fly a bigger distance between clumps, and maybe their foraging goes from once every three seconds to once every four seconds, seemingly minuscule, but that means it’s a 25 percent increase in its energy expenditure to just eat.
“So if you think of the development Cari has referenced, people have moved to the Valley and there are a lot of rural areas across Colorado and the U.S. that have seen this shift because of COVID. If you just drive from South Fork to Creede, or anywhere along our river ways, you can see where a new house is, and you can see that people clear vegetation to the water because it gives them a better view, better access or whatever. But if you imagine, if you add all that cleared vegetation up, you’re having a huge impact in foraging areas for neotropical migrants and other wildlife.”
“And the same goes for grassland species,” Aloia adds, bringing more context and perspective to the conversation. “Nationally, continentally, we’ve seen a huge decline in grassland species. They took it really hard with that September snow that we had a year ago, and if you drive down the (county road) 8 South between Monte Vista and Alamosa, if you drive that road, the amount of clearing that has gone on just with greasewood, rabbit brush, sort of the more upland species that you don’t usually equate with wetlands, and having those sort of temporarily flooded areas that we identified in the assessment as being something that we’ve lost significantly, those areas are being cleared, and what we have is exposed ground now and weeds, and all kinds of things.
Photo credit: Ryan Michelle Scavo
“If you drive that in the spring and the fall, or if you’ve ever walked through a greasewood area, the amount of birds that are utilizing those types of areas is astounding. And we’re losing that habitat. As we know, at least 82 percent of all wildlife species use riparian areas or wetlands in some capacity during their life history. So even though we may look at those as really upland species, there is a lot of crossover between different habitat ecosystem types. So then we can’t just focus on a specific riparian or wetland area, we have to look at the system as a whole and see how we’ve really fragmented everything.
This year Nehring and Aloia noticed what they characterized as a “huge change in the bird migration for water fowls coming to the San Luis Valley.”
“We saw a three week shift in when the geese were breeding and bringing off their broods,” said Aloia. “We didn’t see the water fowl coming into the Valley as early as they usually do in the fall. It’s much later, and honestly I don’t even know that we’ve really seen it yet.
Sandhill Cranes West of Dunes by NPS/Patrick Myers
“We obviously have the cranes coming through and they sort of straggle in, in the fall. But in terms of water fowl they know that our water resources this year were low, they have a sense for that, and can just pass us by. Because they have wings, they are able to shift and go where resources are and I think we’re going to see that more and more.”
Nehring referenced a widely publicized study first reported in the journal Science that documented the loss of 3 billion birds, or one in every four birds, since 1970. “I’m thinking now, 3 billion birds in 30 years, that’s really dramatic but I think we’re entering into a new time period where we’ll have equally dramatic losses in a shorter period of time,” she said.
“And I think it’ll not only be birds,” said Aloia, “but it’s going to be other bigger wildlife species that may garner more attention because they’re more identifiable, more people know about them. We as biologists have definitely seen how the birds have changed in their movements and numbers, but I think that it’s definitely going to become more apparent to a bigger part of the population.”
