Pioneer of Trophic Cascade Robert T. Paine an American ecologist…

The short film “Some Animals Are More Equal than Others: Trophic Cascades and Keystone Species” opens by asking two fundamental questions in ecology: “What determines how many species live in a given place? Or how large can each population grow?” The film then describes the pioneering experiments by Robert Paine and James Estes, in the 1960s and 1970s, which started to address them. Paine’s experiments on the coast of Washington state showed that the starfish is a keystone species, having a disproportionately large impact on its ecosystem relative to its abundance. Estes and colleague John Palmisano discovered that the kelp forests of the North Pacific are indirectly regulated by sea otters, which feed on sea urchins that consume kelp. The presence or absence of sea otters causes a cascade of direct and indirect effects down the food chain, which in turn affect the structure of the ecosystem. These early experiments inspired countless others on keystone species and trophic cascades in ecosystems throughout the world. Source film guide and educational materials.

Paine dealt a serious blow to the dominant view in ecology of the time: that ecosystems are stable dramas if they have a diverse cast of species. Instead, he showed that individual species such as Pisaster are prima donnas, whose absence can warp the entire production into something blander and unrecognizable. He described these crucial creatures, whose influence far exceeds their abundance, as keystone species, after the central stone that prevents an arch from crumbling. Their loss can initiate what Paine would later call trophic cascades — the rise and fall of connected species throughout the food web. The terms stuck, and ‘keystone’ would go on to be applied to species from sea otters to wolves, grey whales and spotted bass. —Ed Young, Nature Magazine January 16, 2013 Scientific American

The wolf is a keystone species. Jerome Helmer, Ark Nature

Robert T. Paine, (Robert Treat Paine III), American ecologist (born April 13, 1933, Cambridge, Mass.—died June 13, 2016, Seattle, Wash.), was an icon in the field of ecology and the originator of the keystone species hypothesis, which posited that some species (typically large predators) have a disproportionately large effect on the biological communities in which they occur. Paine received a B.S. (1954) from Harvard University and earned a Ph.D. in zoology (1961) from the University of Michigan before joining (1962) the University of Washington as an assistant professor in the department of zoology. Paine unveiled (1969) his keystone species hypothesis after researching the ochre sea star (Pisaster ochraceus), a predatory species in the tidal pool communities on Tatoosh Island in the Pacific Northwest. After removing all of the sea stars from the tidal pool, he discovered that the mussel population rose dramatically. The mussels covered the rocky surfaces of the tidal pool to the detriment of other tidal pool denizens (limpets, barnacles, and sponges) and thus changed the structure of the tidal ecosystem. He noticed similar patterns in kelp forest ecosystems when sea otter populations declined; the population of their prey, sea urchins, grew large, consuming enough kelp to drive away other animals that would normally feed on that seaweed. Paine’s groundbreaking keystone species concept, which was later clarified to describe the impact of strong single-species relationships that were out of proportion with the species’ biomass in the ecosystem, became an important factor in conservation; many ecologists used his model to guide their decisions on which habitats and ecosystems to protect to maximize biodiversity. Paine was presented with the MacArthur Award from the Ecological Society of America in 1983 and the International Cosmos Prize in 2013. Encyclopdia Britannica

Photo courtesy of Benjamin Drummond for The Natural Histories Project:

Gray wolves in northern Wisconsin are saving the forest 

The Research,  The work took place at Notre Dame’s Environmental Research Center that straddles the border between Michigan’s Western Upper Peninsula and Northeast Wisconsin. The site has forest, bogs and swamps, with red and sugar maples as the dominant hardwoods — a preferred food for deer.

Of wolves, deer, maples and wildflowers by Eric Freedman first published on June 16, 2016 Source breaks the results of the research down in the following article:

Grey wolves are good for wildflowers like the nodding trillium and the Canada mayflower in the Great Lakes region. They’re also good for young red maples and sugar maples.
That’s because white-tailed deer are bad for both wildflowers and maple saplings. And wolves are bad for deer.

WDNR photograph of White-tailed deer in Wisconsin

With the resurgence of wolves in the region, smart deer are learning to keep away from areas with many of the predators, meaning that wildflowers and young maples there have a better chance of survival, according to a recent study by scientists from the University of Notre Dame and the Michigan Department of Natural Resources.

The work took place at Notre Dame’s Environmental Research Center that straddles the border between Michigan’s Western Upper Peninsula and Northeast Wisconsin. The site has forest, bogs and swamps, with red and sugar maples as the dominant hardwoods — a preferred food for deer.

In scientific terms, it’s not a question of deer getting smart. Rather, they adapt their behavior in wolf-heavy areas to improve their chances of survival — and incidentally improve the survivability of the maples and forbs, or herbaceous flowering plants. On a practical level, that means deer have adapted by spending less time foraging in “heavy wolf use areas,” the study found.

We conclude that wolves are likely generating trophic cascades which benefit maples and rare forbs through trait-mediated effects on deer herbivory, not through direct predation kills.”

Biologists call the process “trophic cascades.” The phrase refers to “trait-mediated” indirect effects that carnivores, meat-eaters, have on plants by killing plant-eaters or changing plant-eaters’ behavior. In other words, trophic cascades happen when predators, in this case, wolves, kill or change the behavior of their prey, in this case, deer, in ways that benefit the type of plants that deer eat.

Wolves in Wisconsin photograph by WDNR

Plant-eaters can have a major impact on environmental change, including biodiversity and the structure of plant communities, the study said, and the findings may help managers of wildlife and public lands in the Great Lakes region.

Historically, wolves were “the natural top predator of Great Lakes deer,” the researchers noted, but hunting eliminated them in the study area by the late 1950s. They stayed extinct in the area until the MDNR discovered a new pack around 2000-06.

The department’s winter 2015-16 survey found a “minimum population or 618 wolves in the U.P. That’s “a very conservative count,” said Kevin Swanson, a Marquette-based wildlife management specialist in the MDNR bear and wolf program. White-tailed deer populations in Great Lakes forests increased dramatically without grey wolves, a trend with “significant negative impacts on forest sapling growth and forb biodiversity,” the study said.

There are no official estimates of the U.P. deer population but numbers are “the lowest for several decades” due to recent back-to-back hard winters, said Swanson, who was not involved in the wolf-deer-maple-wildflower research project.

Lead author David Flagel, assistant director of Notre Dame’s Montana-based Environmental Research Center West, said an estimated 5 to 15 percent of Wisconsin deer die each winter,
Originally, deer in the region chowed down on yellow birch and eastern hemlock, “but the combination of lingering logging effects and years of deer eating saplings has eliminated a lot of them from the understory,” Flagel said.

Maples are “not an absolute favorite,” but once the preferred birch and hemlock are gone, they’re “going to eat something else. Like with your fridge at home,” he said.
The study said, “Deer exhibited very different behavior in areas of high and low wolf use. Deer visited high wolf-use plots less frequently than they did low wolf-use plots, and the duration of the visits to high wolf-use areas was shorter. Deer also spent a lesser proportion of their time foraging in high wolf-use areas.”

Differences were dramatic. Deer density was 62 percent lower in high-wolf areas, where deer visits were 82 percent lower and foraging time was 43 percent shorter, it said.
And what about the maple saplings and wildflowers?
Not surprisingly, deer browsed a significantly larger proportion of them in low wolf-use areas, while the richness of wildflower species “was also significantly affected by wolf use,” the study said. The average richness of the wildflowers increased from 38 to 110 percent in low wolf-use sites.
“The results of the experiments revealed that the negative impacts of deer on sapling growth and forb species richness became negligible in high wolf-use areas,” the study said. We conclude that wolves are likely generating trophic cascades which benefit maples and rare forbs through trait-mediated effects on deer herbivory, not through direct predation kills.”
Study co-author Dean Beyer Jr., a MDNR wildlife biologist, called the findings “an important step, albeit, an early step in investigating trophic cascades in the Great Lakes region.”
He said, “We have known about deer response to wolves for quite some time, including a1980 study that found increased deer use of areas between wolf territories.” And in a 2014 report on research in the south-central U.P., Beyer and other scientists discovered that adult does avoid core areas that wolves use.
If additional research produces similar results, “I would expect that this information would eventually begin to influence forest and wildlife management plans,” Beyer said.
The study appeared in the journal “Community Ecology.”

Featured image John E Marriott