Ocean Blue Blog
by Melynda Beam
For centuries, the white-spotted, dark brown northern spotted owl could be abundantly found throughout the old-growth forests in the Pacific Northwest. These dense forests provided the needed protection for owls, thought to be the male, to relatively easily determine a perfect nesting location. Even with a bounty of eligible nesting sites, these monogamous organisms do not reproduce often and have a low juvenile survival rate. However, when loggers came into the scene, logging around 80 percent of the old growth forests from Northern California to British Columbia since the late 1800s, the spotted owl began to disappear with the forest.
The logging industry was a primary source of jobs for about a century, cutting down over 15 billion board feet per year across the Pacific Northwest in its prime after World War II. This led to habitat fragmentation, where one large area is divided up into smaller areas, and isolation between species. When nature-enthusiasts and environmentalists began to notice an increasing amount of dense forest being replaced by clear-cuts in the 1980s, they began to form protests in larger cities and take direct action in the forests, bringing national publicity to the controversy.
The Northwest Forest Plan
As an indicator species, when the northern spotted owl is abundant, it shows that diversity throughout the forest is plentiful. With the disappearance of the spotted owl, a sign that a decline is occurring in diversity and health of the forests is present. The spotted owl in addition to the biotic and abiotic features around the owl species collectively form these ecosystems that provide an array of services to humans and their environment. These ecosystem services include the hindrance of flood, landslide, and soil erosion; these services also further lead to improvements in nutrient-dense soil, salmon fisheries, water quality, and greenhouse gas reduction. Additionally, cultural services, recreational activities and aesthetic sights, are delivered. Knowing these factors, many environmentalists were quick to stand up for the spotted owl as the population began to drastically decrease.
The spotted owl was placed on the Endangered Species Act as “threatened” in 1990, and the following year, a federal order to stop logging in spotted owl territory was granted until a plan was fabricated for total ecosystem conservation. Meanwhile, “save a logger, eat an owl” became the widely used phrase among loggers and those in support of logging for business purposes. By reserving the habitat of the owl against logging companies, pressure was placed on private and state lands for their timber, and the fear of a loss of jobs was high. The fear of a loss of natural wilderness and all of its inhabitants held by the conservationists was pitted against the fear of a loss of livelihood held by the loggers, creating an atmosphere of animosity.
As tension grew, president Bill Clinton sought to halt the enmity by holding a Northwest Forest Summit in Portland, bringing environmentalists, timber representatives, scientists, fishermen, and local officials together. This led to the emergence of the Northwest Forest Plan one year after. 24 million acres of Pacific Northwest federal areas were set aside for forest protection in conjunction with yielding sustainable and foreseeable timber sales. The plan guaranteed timber yields of approximately 1.1 billion board feet per year in Washington, Oregon, and Northern California public forests, which was an 80% decrease from previous yields. The plan never satisfied this promise and was unsuccessful overall for timber sales. The plan did, however, prove to be successful for owl conservation due to the amount of forest not becoming clear-cut areas. Conservationists saw this not only as a win for the owl but also for the rest of the forest ecosystem and all of its components. Little did they know that they also had a win against the forces of climate change. In a 2016 study conducted at Dartmouth College, clear-cutting was found to stir up and loosen stored carbon in the soil. This, in turn, elevates the risk of carbon returning to the atmosphere as carbon dioxide, playing a role in climate change along with the loss of trees.
Although, even with logging companies at bay, the northern spotted owl populations continued and are still continuing to decline at an average rate of 3.7% per year. Forest fires continue to swarm much of these old growth forests, a reason why loggers also argued the importance of cutting trees in these areas, but the spotted owl faces an even larger issue encroaching on its territory. The primary cause of their decline is now seen to be due to the nonnative barred owl species. With new information that the barred owl was the primary threat, not the loggers, to the spotted owl, a new plan was essential for the survival of the species.
In 2011, the U.S. Fish and Wildlife Service (FWS) made revisions to the plan for the northern spotted owl, recommending that the superior areas of the residual habitat of the spotted owl should be protected. Federal lands still protected under land use plans are still a focus, but for full recovery, other areas will likely need protection. They also recommended to decrease competition due to the invasive barred owl species. To accomplish this, they advocate for control of populations of barred owls to see if the two species can coexist. Additionally, they suggest the use of “experimental removal” of barred owls in conflicting areas to see effect on spotted owls. As a third recommendation, the FWS suggests the use of active management to regenerate ecosystems of the forest. To achieve this, actions that facilitate resiliency against climate change, natural disasters, and disease should be taken in conjunction with continuous refinement and evaluation of management strategies.
This new plan came with recommendations, whereas the former held regulations. There is now much less pressure placed on logging companies as the primary focus of a threat has shifted towards the barred owl. Conservation of the old-growth forests is still seen as a primary focus, and timber companies are reviewing their practices that may have adverse effects on flora and fauna. However, there were no concrete plans for conservation, and only recommendations, studies, and protocols were provided. No incentives were provided for logging companies to stop cutting down old-growth trees, and environmentalists fear that conservation of the spotted owl and old-growth forests may not continue. This plan was also released before the deadline, neglecting to utilize the extra time to seek for further public opinion and comment.
Risks for the Spotted Owl
The barred owl has recently been recognized as the primary threat to the northern spotted owl. Historically, the barred owl was native to eastern North America; however, the owl is quickly invading the territory of the northern spotted owl. The first appearance of the barred owl was in British Columbia in 1943, where it then was noted to be in Washington in 1965, Oregon in 1974 and California in 1981. The barred owl has a higher reproduction rate and is more abundant than the spotted owl; the nonnative is also larger and more aggressive than the spotted owl, giving it more of an advantage when habitat is scarce. Following the DNA sequencing of the northern spotted owl, the California Academy of Sciences’ first animal genome has been congregated hybridization of the northern spotted owl and the barred owl. In collaboration with the University of California Berkeley (UC Berkeley), University of California San Francisco (UCSF), the National Museum of Natural History in Paris, and the Howard Hughes Medical Institute, Academy scientists extensively mapped the bird's genetic material to better understand how this threatened forest dweller is interacting with non-native owls invading its habitat. The two species have been observed to be producing offspring with one another since the 1980s. Hybrids have been found to display physical and vocal attributes of both owl species.
In Oregon, gene flow of the northern spotted owl has been restricted by the Cascade and Olympic mountains as well as dry, low-elevation valleys but facilitated by the Oregon Coast Range. A decrease in genetic diversity can be said to be due to population bottlenecks, a decrease in population size, and inbreeding. In a study conducted by Funk et al., evidence was compiled, revealing the presence of population bottlenecks believed to be due to the barred owls and habitat loss. Due to the bottleneck, loss of an effective population size or the number of organisms producing offspring for the future generation, a decrease in genetic variation is a possible threat to the spotted owl. As the population size decreases, the likelihood of inbreeding increases, lowering the success rate of reproduction and survival. Due to less variability and mutations in the genes, the spotted owl will continue to lose its adaptability as more inbreeding occurs. This finding also reveals that conservation will have to go beyond protecting areas and controlling the nonnative species in order to maintain a sustainable spotted owl population.
As genetic diversity of the spotted owl continues to decline and the effects of climate change continue to worsen, the risk of disease among owls will also likely increase. As climate change occurs, areas that were once cooler are becoming warmer, allowing an increase in vector-borne diseases to spread to these new areas. Although it is only speculation, scientists believe the spotted owl is susceptible to blood parasitic diseases, such as West Nile Virus. To add to the upper hand of the barred owl, they are also less susceptible to disease than the northern spotted owl. In a study conducted by Ishak et al., the spotted owl species was found to have a substantially higher number of owls possessing several blood parasite infections in comparison to the barred owl species, suggesting the presence of a compromised immune system. Additionally, as the barred owl has moved into the habitat of the spotted owl, there is a high likelihood that diseases of the barred owl will also move into the territory of the spotted owl. As the encroachment of the barred owl and the effects of climate change increase on the spotted owl,
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