Huge grasshopper found during vegetation surveys in Swaziland during the Southern African Field School. When in flight, these grasshoppers reveal beautiful pink wings that are hidden in this photo. Photo by teaching assistant Amanda Droghini.
Diana Stralberg will be presenting her thesis defense seminar on Tuesday, November 3 at 1pm in the University of Alberta Biological Sciences Building room CW313. Check out her abstract below.
Abstract: Often referred to as North America’s bird nursery, the boreal forest biome provides a resource-rich environment for breeding birds, supporting high species diversity and bird numbers. These birds are likely to shift their distributions northward in response to rapid climate change over the next century, resulting in population- and community-level changes. Using a new continental-scale avian dataset, I have developed models to project climate-induced changes in the distribution and relative abundance of 80 boreal-breeding passerine species. For such projections to be useful, however, the magnitude of change must be understood relative to the magnitude of uncertainty in model predictions. In my first chapter, I found that the mean signal-to-noise ratio across species increased over time to 2.87 by the end of the 21st century, with the signal greater than the noise for 88% of species. I also found that, among sources of uncertainty evaluated, the choice of climate model was most important for 66% of species, sampling error for 29% of species, and variable selection for 5% of species. In addition, the range of projected changes and uncertainty characteristics across species differed markedly, suggesting the need for a variety of approaches to climate change adaptation.
Species and ecosystems may be unable to keep pace with rapid climate change projected for the 21st century, however. In my second chapter, I evaluated an underexplored dimension of the mismatch between climate and biota: limitations to forest growth and succession affecting habitat suitability. I found that end-of-century projected changes in songbird distribution were reduced by up to 169% when vegetation lags were considered, indicating that limits to forest growth and succession may result in dramatic reductions in suitable habitat for many species over the next century. I used these results to identify conservative and efficient boreal conservation priorities anchored around climatic macrorefugia that are robust to century-long climate change and complement the current protected areas network.
Vegetation change may also be delayed in the absence of disturbance catalysts. In the western boreal region, a combined increase in wildfires and human activities may aid these transitions, also resulting in a younger forest. In my third chapter, I developed a hybrid modelling approach based on topo-edaphically constrained projections of climate-driven vegetation change potential, coupled with weather- and fuel-based simulations of future wildfires, and projections of large-scale industrial development activities, to better understand factors influencing decadal-scale upland vegetation change. I simulated scenarios of change in forest composition and structure over the next century, conservatively concluding that at least one-third of Alberta’s upland mixedwood and conifer forest is likely to be replaced by deciduous woodland and grassland by 2090, with a disproportionate loss of both young and old forest classes. During this timeframe, the rate of increase in fire probability diminished, suggesting a negative feedback process by which a warmer climate and more extensive near-term fires leads to an increase in deciduous forest that in turn, due to its relatively low flammability, leads to a long-term reduction in area burned.
Finally, boreal species’ projected range shifts could be impeded by the northwestern cordillera, which separates boreal Alaska from the rest of the North American boreal region, and appears to have historically prevented many species from expanding into climatically suitable habitat after the last glacial maximum (LGM). Using paleoclimate simulations for the past 20,000 years, I analyzed the relative importance of migratory and life-history characteristics vs. climatic factors on the distributions of North American boreal-breeding species. I then used this information to predict which species are most likely to shift their distributions from Canada into the Alaskan boreal region in the future. The high relative importance of climatic suitability within the northwestern cordilleran region suggests a capacity for several species to disperse into Alaska once climatic connectivity is achieved in the future, which is supported by recently recorded signs of breeding activity.
In an earlier blog post, Anjolene Hunt detailed the daily routine of her and her field assistants tracking the movements of Canada warblers. I thought I’d do the same for the small mammal trapping I conducted with my crew this summer. As part of my research on the effects of industrial noise on owls in the boreal forest of northeastern Alberta, I’m also interested in finding out if those same sources of industrial noise have an impact on the abundance of small mammals, the main food source of owls. This year we set out 64 live traps at each of 23 different sites (each just over a hectare in size) and trapped each site for four days in a row.
Here’s what the daily routine for small mammal live-trapping is like:
5:30 am – We’re up out of our tents, dressed for the field and eating breakfast. In July it was already light out at this time, but by the last couple weeks at the end of August we needed our headlamps to get ready.
6 am – We leave our camp and drive to our sites.
6:30 am – We arrive at the first of three sites and start checking the traps. At each trap, we check if the door is open and if it is we lock it open so that no animals get caught in there during the day. If the door is closed, we find a comfy spot on the forest floor and take out our trapping kit. We open up the trap into a mesh bag. Once we get the animal in there we can take a closer look to see what species it is. Deer mice and red-backed voles were our most commonly captured species, but we also caught a few meadow voles, a chipmunk, a weasel, and a flying squirrel. Every animal caught gets weighed with a spring scale, checked if they’re male or female, and ear tagged with a small metal ear tag, each with a unique number. After all that, we open up the bag and let them go, and watch them disappear into the underbrush. There’s a good chance we’ll catch that same guy in the next couple days, sometimes in the same trap or in one of the other ones nearby.
11 am – By this time we’ve usually finished checking all the traps we set out and head back to camp for lunch.
12 to 3 pm – We use this time in the middle of the day to catch up on data entry, but also to catch up on sleep, go swimming in a local lake, pick berries or some other relaxing activity.
3:30 pm – Dinner time! The four of us would each take a turn cooking dinner, and we had some excellent camp food over the summer.
4 pm – We head out again to our sites to set the traps. Each trap gets baited with a handful of sunflower seeds and a small piece of apple. We also stuff each trap with bedding so the animals can make a nest in there overnight. Lastly, we unlock the door and put a smear of peanut butter at the entrance of the trap to entice the animals inside.
8 pm – By this time we were typically back at camp for the evening, enjoying hot chocolate around a campfire, playing cards or reading before heading to our tents for the night.
Post by Julia Shonfield.
A fly with its head in a flower. If you look closely you can see why: there’s a very cryptic spider eating it. Photo and post by Julia Shonfield
Between June and August of 2015, field crews led by Clayton Lamb conducted a grizzly bear population inventory in the threatened Kettle-Granby Grizzly Bear Population Unit. Crews set 124 bait sites across the ~8,000 km2 area, which consists of rotten cow blood enclosed by barbed wire to non-invasively collect grizzly bear hair, which is then used to identify individuals through multi-locus genotyping. The bait sites were checked for hair samples at two week intervals, with most sites being checked four times throughout the summer.
A total of 1360 hair samples were collected, and field staff visually identified 29 percent of the samples as grizzly hair. The hair samples are currently at the genetics lab (Wildlife Genetics International) in Nelson, and we expect to have the genetic results back before March 2016. During fiscal year 2016-17, the genetic data will be used to generate population estimates and address questions regarding population size, composition, connectivity and the distribution of grizzly bears within the study area.
Post by Clayton Lamb.
Small mammal live-trapping is a bit like a treasure hunt, you never know what will be inside a closed trap. Post and photo by Julia Shonfield.
The coastal temperate rainforest is one of the rarest ecosystems in the world, and a major portion of the global total is found in Southeast Alaska. In this ecosystem, Sitka black-tailed deer are the dominant large herbivore, influencing large carnivores that prey on deer such as wolves and bears, as well as plant species and communities through browsing. In addition, deer play an important economic and cultural role for humans in Southeast Alaska, making up the large majority of terrestrial subsistence protein harvested each year as well as providing the backbone of a thriving tourism industry built around sport hunting. Given the importance of deer in this system, there remain a surprisingly large number of gaps in our knowledge of deer ecology in Southeast Alaska. These knowledge gaps are potentially troubling in light of ongoing industrial timber-harvest across the region, which greatly alters habitat characteristics and value to wildlife. This talk covers the results of a 4-year research project to quantify 1) patterns of reproduction and fawn survival, 2) population dynamics in response to environmental variability, and the underlying drivers of spatial selection during 3) reproduction and 4) winter. In addition, the talk will include the results of a recent wolf-deer-habitat modeling effort aimed at understanding outcomes of future land-use, climate, and trapping scenarios on wolf abundance.