Earth Day is getting interesting. Discussions on conservation and environmentalism have gone cosmic. Some argue that much of the contentiousness of environmental politics, especially the divide between economics and environmentalism, represents the New Holy Wars.

Since the days of Gifford Pinchot and John Muir, debate has raged on the relationship between human beings and nature. Should public lands be preserved untouched or made available for “wise and multiple use”? Is nature better left alone to achieve some perceived state of equilibrium or balance? Or is the very idea of a balance, stasis or equipoise, a steady state if you will, really a misperception of a world characterized by flux, upheaval, dynamism and change? Moreover, is mankind a “natural” part of the landscape or an alien invader, a destroyer of worlds? And which version of nature do we want to exploit, protect or restore?

Daniel B. Botkin, a leading ecological scientist, wrote a path-breaking book, a genuine intellectual stimulant, Discordant Harmonies: A New Ecology for the Twentieth-First Century (1990), which demonstrated how human misperceptions of a natural balance in nature actually obstruct solid, scientific efforts at protection or restoration. A revised and updated version of this book will be issued by Oxford University Press in August.

Botkin noted that even a very wild place like the Boundary Waters Canoe Area in northern Minnesota, which “could persist with the least direct human intervention,” has, from the end of the last ice age until the time of European colonization, “passed from the ice and tundra to spruce and jack pine forest.”

The shift from tundra to spruce to jack and red pine, then to paper birch and alder, and then back to spruce, jack pine and white pine was driven by variable climate. “Which of these forests represented the natural state?” asked Botkin.

“If natural means simply before human intervention, then all these habitats could be claimed as natural, contrary to what people really mean and really want,” wrote Botkin. “What people want in the Boundary Waters Canoe Area is the wilderness as seen by the voyageurs and a landscape that gives the feeling of being untouched by people.”

Human beings, interacting with natural conditions and climate, have had a big impact on their environments since before Native Americans stampeded buffaloes over cliffs or set fires to drive game or cultivate crops. We have for millennia made choices — some good, some bad — about our landscapes, watersheds and natural world.

Ironically, we are now destined to be the instrument for saving, conserving or restoring nature whether we like it or not. There is no other choice. Inaction is not an option.

Matt Ridley, the author of The Rational Optimist: How Prosperity Evolves (2010), wrote a perceptive review last month of a new book by Emma Marris, The Rambunctious Garden: Saving Nature in a Post-Wild World (2011). Marris, says Ridley, explores the paradoxical truth “that the only way to have a pristine wilderness is to manage it intensely. Left unmanaged, a natural habitat will become dominated by certain species, often invasive aliens introduced by human beings.”

“‘A historically faithful ecosystem is necessarily a heavily managed ecosystem,’ she writes. ‘The ecosystems that look the most pristine are perhaps the least likely to be truly wild.'”

To let aspen, willow and beaver return to Yellowstone, it was necessary to reintroduce the wolf, which reduced elk numbers. Mojave Desert tortoises demand control of ravens whose numbers have skyrocketed due to landfill sites.

Take an example from the Great Lakes. There would be no commercial or recreational fishing to speak of in the Great Lakes absent the exertions of the U.S.-Canadian Great Lakes Fishery Commission (GLFC) to cope with a parasitic invasive, the sea lamprey.

The sea lamprey infiltrated the basin, from the Atlantic, via the Welland Canal, which was opened in the early 19th century. Niagara Falls did serve as a kind of barrier until the Canal was modified in 1919.

A single sea lamprey can destroy 40 pounds of fish in its lifetime by attaching its mouth to its prey by means of suction. One metric used in the program is the wounding rate found on targeted fish species.

As the eel spread to all five of the lakes, it decimated both native fish and stocked salmon, which had been introduced intentionally, a human intervention in and of itself. An extensive program of trapping, pinpoint poisoning, velocity barriers (the sea lamprey is a weak swimmer) and introduction of sterilized males has been going on for decades. It is a very substantial investment without which there would simply be no Great Lakes fishery. Chris Goddard, Executive Secretary, and Marc Gaden, Communications Director for the GLFC, inform me that the total invested in this program over the decades amounts to nearly $450 million. The good news is that the entire fishery is valued at $7 billion. Some analysts have calculated a positive benefit-cost ratio approaching 17-1.

Emma Marris also rejects the idea of a balance of nature as an equilibrium tending toward a steady state. She quotes Botkin, who stated: “If you ask an ecologist if nature never changes, he will almost always say no. But if you ask that same ecologist to design a policy, it is almost always a balance-of-nature policy” — preserve rare species, maintain this habitat structure, freeze in time this ecological moment, return this degraded land to a particular state regardless of weather or invasive species.

“Give up romantic notions of a stable Eden, be honest about goals and costs, keep land from mindless development and try just about everything,” argues Marris.

Like shooting more deer. Yes, even the national Park Service (NPS), which manages Washington, D.C.’s Rock Creek Park, is resorting to sniper fire by government sharpshooters equipped with night-vision goggles and silencers to control this universally acknowledged threat to healthy forests, vegetation, and biodiversity. NPS’s new deer management plan calls for killing 80 percent of the white-tailed deer, or more than 300 animals living in the area, over a three-year period. Bambi, you’ve been warned.

The 2,820 acre park has 80 deer per square mile. Its forest and trees will be decimated in a few years. Right now cars are the only predators out there, killing more than 40 deer each year. “The deer are grazing on all our new regrowth,” said Nick Bartolomeo, the park’s chief ranger. “The forest can’t regenerate.” The plan is to reduce the population to 15 or 20 animals per square mile.

Meat from the dead deer will be given to local food banks and homeless shelters.

This debate over nature and humans has flared up, ferociously, early this year in the Breakthrough Journal with top scientists from the Nature Conservancy criticizing other mainstream conservationists or preservationists for failing to account for the role of humans in ecosystems. Vigorous rebuttals have been lodged by several others, including the head of the Center for Biological Diversity.

“By its own measures, conservation is failing,” opine the TNC scientists. And there is this: “Conservation’s binaries — growth or nature, prosperity or biodiversity — have marginalized it in a world that will soon add at least two billion people.” These are fighting words in some quarters.

As in past years, the observance of Earth Day 2012 provides this writer with another chance to showcase examples of human beings improving or restoring the natural world and environment.

Recently, I offered TAS readers an update on the phenomenal growth of the private land trust movement, private philanthropy in service of protecting landscapes, watersheds, agriculture and aesthetics. In Michigan, a state that has suffered so much during the economic downturn, a coalition of land trusts, the Heart of the Lakes, protected nearly 40,000 acres just in 2010 for a grand total of 548,318 acres through voluntary conservation easements. This is typical of what is happening all around the country.

In my wife’s home state of Wisconsin, state fisheries managers, and a supportive public, have worked for decades on a project to protect and expand the range of a prehistoric animal that survived the dinosaurs but barely escaped man.

The bottom-dwelling lake sturgeon first appeared 100 million years ago, as the dinosaur exited stage left. “Whatever killed the dinosaurs didn’t kill the sturgeon,” says Ron Burch of the Wisconsin Department of Natural Resources.

A lake sturgeon looks, well, prehistoric with boney plates instead of scales, a flexible rod (“notochord”) instead of a backbone, a long snout and tubular mouth with no teeth. It uses its hanging barbels as feelers to detect snails, insects, leeches, crayfish and small clams which they consume. It is a massive animal and long-lived.

An 82-year-old sturgeon was caught in Lake Winnebago in 1953.

This month, on April 10, a sturgeon 7 feet, four inches in length, weighing 240 pounds was captured on the Wolf River-Winnebago System at the Shawano Paper Mill Dam in a spawning assessment operation to harvest her eggs. She would have been 30 pounds heavier before the eggs were taken. This was the largest lake sturgeon ever captured since 1950. The DNR estimates that she was born in 1887.

Lake sturgeon used to thrive throughout the Great Lakes and Mississippi River basin. Native Americans revered the great fish. Overharvesting, dams, and pollution eventually reduced the population to roughly 10 percent of what it was pre-settlement. I recall reading a description of these large animals being caught, killed, and stacked up to dry out so they could be used as fuel for the boilers of ships that once cruised the Great Lakes.

At the beginning of the 20th century, harvesting was limited. Professional biologists were hired by the state in the 1940s and the generational recovery effort began to take off. Citizens groups with several thousand members helped to reduce poaching with round-the-clock patrols and habitat restoration in the Lake Winnebago-Wolf River System.

From a total spawning population of 11,500 adults in the 1970s, recovery efforts yielded 9,000 adult females and 27,000 adult males by 2000. Sound science, reasonable regulation, and community support provided the winning formula for this success story.

One does not fish sturgeon. One spears sturgeon. The 2012 season came to an end in February. It was a big success at least on Lake Winnebago. Ten thousand sturgeon licenses are sold each season.

There were so many people on the ice during a recent tournament on the lake (the “Battle on Bago” contest) that 36 cars fell through the ice, a foot thick, mostly in shallow water. No one was hurt and all cars were towed out of the water.

Sometimes the relationship between man and nature is a complicated thing, fraught with difficulties. After all, human beings are not bound by the laws of thermodynamics or even evolution. They are very much free agents.

The online environmental news service, Greenwire, carried a story last year regarding the Swedish guy who wanted to build a nuclear reactor in his apartment. This is probably not a good way to reduce your carbon footprint.

An inspection by the Swedish Radiation Safety Authority found radioactive material including small amounts of Americium-241, which is not supposed to be removed from smoke detectors. Do not try this at home.

Whatever our limitations, human beings are the only game in town when it comes to saving nature. I will give Professor Botkin the last word this Earth Day.

“Nature in the twenty-first century will be a nature that we make; the question is the degree to which this molding will be intentional or unintentional, desirable or undesirable.”