Dear EarthTalk: What’s causing the decline in U.S. wild turkey populations? ~ John Groveton, Alexandria, VA
Americans have always loved wild turkeys, perhaps too much. By 1900, we had nearly driven this close relative to the chicken to extinction as a result of unregulated hunting and habitat destruction. But thanks to conservation and relocation efforts, these big birds started making a comeback in the 1940s. Over the next several decades, thanks to a series of reforms and demographic changes, wild turkey numbers grew and the species hit its population peak in 2004 with as many as seven million of them across the U.S. All this made wild turkeys one of the biggest success stories in the history of American wildlife?
But will it last? Since that population peak, wild turkey numbers have fallen, declining some 15 percent between 2004 and 2014 and another 3 percent between 2014 and 2019. Biologists are struggling to determine why. Much of this decline has been in the South and the Midwest. Scientists have been investigating habitat loss, hunting, disease and climate change, as all possible causes of this population downturn.
One of the potential reasons causes for the decline is the rise in turkey-eating predators. Hawks, bobcats, coyotes and raccoons are among wild turkeys’ natural predators. Hawks and owls are protected species and have had significant rebounds since the federal government banned the use of the pesticide DDT. This protection has allowed populations of birds of prey to grow, but they are also key predators of turkeys. This increase in predators could be one of the sources of the turkey decline.
Turkeys have very specific requirements when it comes to their environment, so habitat loss could be another factor of their decline. Turkeys need areas of low, thick vegetation for nesting and raising chicks, and areas with mature trees to provide nuts to eat in the fall. As more natural areas are destroyed, turkeys may be having a harder time finding swatches of land that meets all of their needs.
Climate change is likely another factor. Turkeys may be experiencing a failure to respond to the environmental shifts of climate change. A study published in the journal Climate Change Ecology found that turkeys don’t shift nesting times much as temperatures and precipitation change. This can cause newly hatched turkeys to miss out on plant cover and edible bugs if the spring bloom starts earlier. In turn, this could affect the likelihood that turkey chicks survive into adulthood. We already know that rising temperatures affect over 100 bird species in the Americas; they might be harming turkeys too.
There is more research needed to find a definitive answer to the decline in turkey populations. It is most likely that the answer is the combination of a number of problems. As scientists look for solutions, many states have started to scale back on turkey hunting seasons in hopes of bringing population numbers up again.
CONTACTS: Wild turkey population is declining rapidly, puzzling scientists: ‘It may be a bunch of things all adding together’, https://news.yahoo.com/wild-turkey-population-declining-rapidly-050000176.html; Wild turkeys are disappearing — but no one is sure why, https://www.washingtonpost.com/climate-environment/2023/11/23/wild-turkey-population-decline/; As the climate changes, wild turkeys aren’t keeping up – The Wildlife Society, https://wildlife.org/as-the-climate-changes-wild-turkeys-arent-keeping-up/.
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Dear EarthTalk: Why hasn’t biomass caught on more as a renewable energy source? ~ PJ, via email
Biomass is organic material derived from living or recently living organisms like plants, animals and microorganisms. It can be used as a renewable energy source via combustion, fermentation or conversion to biofuels. Some biomass sources, like oil or alcohol-rich crop residue and animal manure, are widely produced on an industrial scale. As we deplete and intentionally shift away from the pollutive natural gas, oil and coal, optimists believe that biofuel may become a viable widespread renewable alternative.
First-generation biofuels use food crops, like corn and sugarcane, but this diverts resources from food production. Instead, second-generation biofuel uses inedible biomass, like wood and agricultural waste. These are low-cost and can serve also to reduce waste, as they use animal and plant waste that would otherwise go to landfills. The U.S. Department of Energy says using up to a billion tons of biomass each year for biofuel could reduce petroleum consumption by 30 percent and create new domestic jobs.
Biomass proponents call biofuel carbon neutral because the carbon dioxide (CO2) released during its combustion is offset by the amount that is absorbed by the plants during growth. Others believe this overlooks factors like land use change, biomass processing emissions, and the methane released during decomposition. Biomass combustion also releases carbon monoxide, nitrogen oxides and particulate matter, highlighting the environmental and health risks associated with biomass utilization.
It takes decades for biomass-produced carbon to be removed from the atmosphere. Studies suggest that it may even be a dirtier business than fossil fuels, with wood and corn-based ethanol emitting from 1.25 to 1.5 times more CO2 than coal per kilowatt-hour of electricity generated. Research conducted by Harvard’s Jonathan Buonocore suggests that biomass combustion causes more health-related deaths than conventional coal-fired power plants. Moreover, biomass production can contribute to loss of forests and biodiversity, and indirect land use change. Burning biomass can cause significant public health issues, including asthma, heart and respiratory diseases, birth defects, and even death.
Mitigating environmental and health drawbacks and enhancing the effectiveness of current technologies can help make biofuel more viable. Investing in advanced biomass conversion technologies, such as gasification and pyrolysis, can reduce greenhouse gas and toxic byproducts during combustion. Promoting sustainable sourcing practices, including the exclusive use of agricultural and forestry residues rather than dedicated energy crops, can minimize deforestation and habitat destruction.
Biofuels today are more expensive than conventional fuels like natural gas and crude oil. Researchers aim to design processes that better utilize lignin and sugars in biomass. If this can be achieved, biomass-derived aviation fuel could potentially achieve a break-even price as low as $3.15 per gallon of gasoline-equivalent, offering a competitive edge against traditional jet fuel costs. If we can address these health, environmental and technological challenges, we may well realize the full potential of biofuels.
CONTACTS: Health consequences of using biomass for energy, https://www.hsph.harvard.edu/news/hsph-in-the-news/health-consequences-of-using-biomass-for-energy/; Biomass Energy: Climate Solution or Potential Catastrophe? https://kleinmanenergy.upenn.edu/news-insights/biomass-energy-climate-solution-or-potential-catastrophe/; Inexpensive, carbon-neutral biofuels are finally possible, https://www.sciencedaily.com/releases/2024/02/240207120424.htm.
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Dear EarthTalk: How do different regions of the U.S. compare with regard to vulnerability to impending climate threats? ~ Peter Greenville, Detroit, MI
Climate change causes rising temperatures, fluctuating rain patterns and other extreme weather phenomena. However, the effects of climate change are not equally distributed across the country.
Regional climate change experiences can be broadly divided into two categories: (1) geographical and climatic factors (i.e., the actual climate change); (2) and socio-economic factors (i.e., the vulnerability of the population to these changes). It is crucial to understand how different regions experience climate change in order to develop effective climate policies. Some regions, for example, rely on climate-sensitive industries such as agriculture, tourism and natural resource extraction, while others do not. Those that do tend to be home to vulnerable populations like people with low income, and marginalized communities.
The Fifth National Climate Assessment (NCA5) recognized certain region-specific patterns. The U.S. Northeast is experiencing significant increases in extreme precipitation, with some areas seeing up to a 60 percent rise from the historical average. Also, warming water temperatures are impacting local wildlife. In the Southeast, lengthy coasts make the region particularly vulnerable to hurricanes and increasing sea levels. This vulnerability is exacerbated by the region’s reliance on coastal ecosystems and tourism.
Climate change negatively affects the Great Plains’ huge energy sector. Agriculture is disrupted through the depletion of a critical water source: the High Plain Aquifer. The region is also vulnerable to habitat loss, changes in food availability, and other unique problems. The Midwest, with its intense agricultural production, suffers extreme weather events and changes in precipitation patterns that dramatically impact crop yields. A severe drought in 2012 caused billions of dollars in losses to Midwest farmers.
The Northwest’s vulnerable water resources are greatly impacted by higher temperatures. Snowpack, a critical water source, is declining. Also, the region’s extensive forests face a higher risk of wildfires and insect infestations. The Southwest, characterized by a hot and dry climate, is also vulnerable to prolonged droughts, severe wildfires and water scarcity, further straining its already limited water resources.
Alaska and its large population of indigenous people is affected by melting permafrost, coastal erosion and loss of wildlife. Hawaii and the U.S. Caribbean’s coastal communities suffer sea level rise, coral reef degradation and extreme weather events. And the National Oceanic & Atmospheric Administration reports that degradation of coral reefs due to rises in sea surface temperatures could incur coastal damages costing approximately $1.2 billion (in 2022 dollars) annually to Hawaiʻi and the U.S. Pacific territories.
While impacts of climate change vary, it is important to remember no region is immune. We will need to continue to collect and analyze data to fully understand this issue. Furthermore, we need to empower vulnerable communities and prioritize their needs. Finally, we need to make collaborative efforts at the local, state and national levels to truly combat this issue.
CONTACTS: The U.S. Climate Vulnerability Index, https://map.climatevulnerabilityindex.org/; The Fifth National Climate Assessment, https://nca2023.globalchange.gov/.
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