Trophic cascades occur when predators limit the density and/or behavior of their prey and thereby enhance survival of the next lower trophic level. In this situation, by controlling densities and/or behavior of their prey, predators indirectly benefit and increase the abundance of their prey's prey. Trophic cascades are powerful interactions that strongly regulate biodiversity and ecosystem function. Trophic cascades were originally thought to be rare, but now we understand that they occur across diverse terrestrial, freshwater and marine ecosystems, and are common features of many green plant communities, including vascular plant assemblages, long thought to be resistant to consumer control. Although we know that trophic cascades can be more powerful under certain conditions, for example climate stress and nutrient enrichment in salt marshes, much research is needed in this area to refine our understanding of when and where trophic cascades will be important. [Nature]If the free market is such a cool deal, why aren’t cougars and wolves protected instead of slaughtered en masse?
Elaine Brice and Dan MacNulty, from Utah State University’s Department of Wildland Resources and Ecology Center, and Eric Larsen, from the University of Wisconsin Stevens Point’s Department of Geography and Geology, outlined their research in the Nov. 8 publication of Ecology Letters. At its core, the research questions the methodology used to measure aspen for the earlier research, saying the choice of which trees to include skewed the study. One of the problems of relying on only the tallest young aspen trees is that elk are very discerning about which aspen they eat. Using a random sample, the researchers still found evidence of a trophic cascade. Wolves aren’t the only predators of elk. From 1995-2002, the late cow elk hunt near Gardiner, just outside Yellowstone’s northern border, removed between 940 and 2,465 elk a year. [Billings Gazette]Coyotes are mesopredators and will eat anything yet Citibank is too big to fail.
Large carnivores have been frequently extirpated from many ecosystems worldwide as consequence of human persecution or the loss of their habitats and food resources. However, a rewilding process is leading to the recovery of their distribution ranges. Apex predators are at the top of trophic chains and can lead to the so called, top-down effects, this is the modification on the abundance and behaviour of species from lower trophic levels, critically influencing ecosystem structure and functions, what is known as a ‘trophic cascade’. [Journal of the British Ecological Society]Humans tampering with the ecosystem has resulted in a trophic cascade where the slaughter of cougars, wolves and other apex predators has allowed mesopredators like coyotes and bobcats to flourish only to depress grouse numbers.
Every year, John Formby spends weeks flying in a plane above New Mexico’s forests, looking for trees with signs of insect damage and stress from heat and drought. The state forest health specialist’s latest report shows damaged forests increased by about 240,000 acres in 2021. “I fear that over the next few years, we may start getting into some dire circumstances as far as piñon and ponderosa go,” Formby said. [Albuquerque Journal]Global warming has been accelerating since humans began setting fires to clear habitat, as a weapon or just for amusement. Evidence that we humans have eaten or burned ourselves out of habitats creating catastrophes behind us is strewn throughout the North American continent.
Allowing Mexican gray wolves to inhabit north-central New Mexico would help restore genetic diversity to the Mexican population, all 186 known members of which in the United States are descended from just seven wolves rescued when the subspecies was on the brink of extinction in the late 1970s. The Fish and Wildlife Service said it’s too soon to know how the two programs in New Mexico and Colorado might interact and cooperate moving forward. [Taos News]The Anthropocene is a trophic cascade, humans have altered and continue to alter every food web and the Trump Organization distorted the science to appease Republican ranchers.
“We’ve known for some time that bison don’t spend as much time in wetland areas as cattle do, but what we didn’t understand was how this difference was going to influence biodiversity. When we looked at areas where bison were reintroduced, and compared them to similar areas with cattle, we found that the vegetation along small streams changed in ways that are associated with more diverse bird communities and increased use of these areas by native ungulates like white-tailed deer. Bison reintroduction is resulting in healthier more biodiverse riparian environments, which is great news for tons of other prairie species.” [American Association for the Advancement of Science]