Habitat loss is one of the driving forces behind declines in birds and other wildlife, so restoring habitat after humans have disturbed it is an important conservation tool. Restoration often involves revegetation, which may seem simple in theory- cut down a tree, plant a tree. However, revegetation is rarely simple in practice because real forests don’t grow in controlled, unchanging environments. If you cut down a stand of mature white spruce, then replant the area with white spruce seedlings those seedlings are not growing up in the same environment that the original spruce trees did. There may be a drought now, a new invasive tree species might be present, a wildfire might come through.

Likewise, wildlife does not always neatly track the process of revegetation in a simple “if you build it, they will come” manner, a la the movie Field of Dreams. Just like trees, animals exist in a dynamic environment. Even for highly mobile animals like birds there may be lags in colonization and local extinction. If a species has declined in the region, there will be fewer individuals of that species available to recolonize your spruce stand. Or, your stand may not yet have dead snags to provide nesting sites for woodpeckers. Or, maybe a species characteristic of an earlier successional stage hangs on for a few years, even though the habitat has become less suitable, because it has high fidelity to its breeding site.

Understanding the ways in which bird communities respond to disturbance and revegetation in a dynamic environment is crucial for successful habitat restoration and bird conservation. In a recent paper in the Journal of Environmental Management, researchers from the University of Alberta, Owl Moon Environmental, and The Institute for Bird Populations (IBP) used data from the Monitoring Avian Productivity and Survivorship (MAPS) Program to examine how bird communities in Alberta’s Athabasca Oils Sands Region change following energy-sector disturbance with subsequent reclamation efforts and additional disturbances including wildfire.

The Athabasca Oil Sands region, spanning 54,000 square miles in northern Alberta, is one of the largest sources of unconventional oil (in this case bitumen) in the world. This region also includes a large swath of some of the most critical habitat for migratory birds (not to mention endangered Woodland Caribou) – the North American Boreal Forest. Stretching across Canada and Alaska, the boreal is the largest intact forest on earth, and it is sometimes dubbed “North America’s Bird Nursery." Almost half of bird species occurring in Canada and the U.S. either breed in the forest or use it as stopover habitat during migration. The Boreal Songbird Initiative notes that 80% of the continent’s waterfowl species, 63% of its finch species, and 53% of its warbler species breed in the boreal. Some species breed there almost exclusively, for instance 98% of Palm Warblers hatch among the muskeg and conifers of the boreal forest.

Energy development in the region rapidly expanded in the early 2000s, sparking environmental concerns. In the wake of this expansion, The Oil Sands Monitoring Program (OSM), a joint effort by the Canadian and the Alberta provincial governments, was established to gather environmental data “to ensure responsible development of Alberta’s oil sands area, and to support and promote environmental protection and enhancement” (Oil Sands Monitoring website.) As part of the mandate for environmental protection and enhancement, Alberta requires energy companies to restore disturbed lands to "equivalent land capability" after bitumen extraction is complete. These restoration efforts can employ a variety of techniques, including the improvement and replacement of topsoil, as well as direct revegetation efforts.

As part of the OSM, Ken Foster and Christine Godwin of Owl Moon Environmental, in collaboration with IBP, established a network of MAPS stations across the oil sands region in 2011. (You can read more about their stations in the 2026 issue of MAPS Chat). In this study, data from 34 of these stations were leveraged to assess how bird communities change over time at sites that varied in the extent and type of the initial energy sector disturbance, post-disturbance restoration effort, vegetation recovery, and the timing and degree to which they have experienced subsequent disturbances- including wildfire and additional energy-sector activities.

Many studies of the impacts of environmental disturbance and restoration on communities use a space-for-time substitution approach, as Tharindu Kalukapuge, a Ph.D. candidate at the University of Alberta and lead author of the study explains:

The long-term MAPS dataset allowed Kalukapuge and co-authors to take a different approach, called a “time-lag analysis”, to compare communities at points in time ranging from just a year apart (i.e., a 1-year lag) to points in time that were separated by many years. “By applying this time-lag analysis to the many MAPS sites with varied disturbance and restoration histories, we now have a much more powerful approach that incorporates aspects of both space and time,” says IBP Research Ecologist and co-author of the study Jim Saracco. This approach gave researchers a more nuanced understanding of how bird communities changed after initial disturbances and restoration; as well as the trajectory of that change over subsequent years. This detail is especially important when additional subsequent disturbances affect the sites, like the Fort McMurray wildfire did in 2016. The researchers strongly recommend continued long-term monitoring to evaluate effects of energy sector footprint recovery efforts on wildlife. Again, Kalukapuge elaborates:

Unsurprisingly, the researchers found that the intensity of the initial energy sector disturbance, restoration activities, and successive disturbances had significant effects on the rate and trajectory of changes in the bird community. Consistent with the ‘field of dreams’ hypothesis, recently restored sites with high disturbance footprint showed rapid rates of directional community change and no evidence of time lags or stalled community trajectories within the timeframe of this study. In contrast, less disturbed and older restored sites supported relatively stable bird communities. “We know that even 80 years after the initial disturbance, even though the forest looks recovered, bird communities won't have fully converged.” says Kalukapuge. “It may be because certain elements in the ecosystem are still absent. But we showed there is a hope of recovery!” Successive disturbances like additional energy sector activities, logging, or wildfire, had a cumulative effect and slowed recovery. The researchers suggest adding these considerations to make restoration timelines more realistic. Limiting the size and intensity of the initial energy sector disturbance, and limiting subsequent disturbances to restored sites are important to achieve restored, stable bird communities of mature forest habitats in the Oil Sands Region.

Although the MAPS program was designed to provide population-level demographic metrics like productivity and survival (e.g., Saracco and colleagues used the Boreal MAPS data to examine demographic declines in 31 species of birds in this same study area), the current study shows how MAPS can also provide new insights into other ecological phenomena, such as how avian diversity and bird communities change across space and time.