Over the past hundred years, people have introduced dozens of non-native fish species into the Colorado River and its tributaries. During that time, populations of native fish species have dropped, in some cases dramatically. It’s easy to guess at the causes of native species decline, like predation and competition for food. But it’s far more difficult to prove.
In the depths of the Great Depression, the nation’s unemployment stood at 25 percent. With people hungry and desperate for jobs, President Franklin Roosevelt signed a law in March 1933 creating the Civilian Conservation Corps. The CCC gave jobs to single men 18 to 25 years old, with most of their thirty-dollar-a-month paychecks returned to their families.
Fewer than five percent of the more than 550 U.S. wildlife refuges are located in urban areas. In New Mexico, another is joining the list as the former Price’s Dairy near downtown Albuquerque is slated to become the Middle Rio Grande Wildlife Refuge. At almost 600 acres and only five miles from downtown, it is the largest farm left in a metropolitan area now home to nearly one million people.
When summer’s flashy circus of wildflowers has passed and the last browned autumn leaf has fallen, an eye looking for signs of plant life is left with the conifers, those stalwart trees that stay green all year long.
Conifers do drop their needles and replace them with new ones—just not all at once. Their ability to photosynthesize all year long gives them a built-in advantage in living in places with a relatively short warm season. So does their natural chemical antifreeze, which prevents needles from freezing even in frigid conditions.
This week Earth Notes concludes its series on the sun with a look at how to use a backyard solar oven. You can use one anywhere there’s a few square feet of sunny exposure on a backyard or balcony.
And yes, you can use a solar oven on some winter days. Even when it’s cold and the ground is covering with snow, a cooker will work if you have enough sunshine and your solar oven is well insulated. But you’ll need to use the midday hours when the sun is at least 45 degrees above the horizon—that means your shadow is shorter than your height.
This week Earth Notes continues its series on the sun, with a look at turning your backyard into a kitchen
Just as the inside of a parked car heats up on a sunny day, a solar cooker traps the sun’s rays in its enclosed interior, causing water, fat and protein molecules in the food to heat up. The molecules vibrate vigorously, and the food cooks.
Since time before memory people have used sunlight to make southwestern homes more livable. Many of the region’s characteristic cliff dwellings were carefully sited in places that are shaded in summer, but sunny in winter. That allowed natural heating to reduce the need for warming fuels.
Today savvy builders and homeowners are following in that tradition through clever design. Builders of new houses use passive solar design to bring sunlight in when it’s wanted and exclude it when it’s needed. And smart remodeling, too, can reduce heating and cooling bills.
This month, as nights grow long, Earth Notes pays homage to the sun and to some of the lesser-known ways it can fuel our lives.
It’s well known that photovoltaic solar panels produce clean, renewable energy. But a new study suggests that they can have an unintended consequence: in some climates, panels mounted on roofs may help keep interiors cool in summer and warm in winter.
Each year an average of 250 people are rescued from inside Grand Canyon. Many of them are hikers unprepared for the substantial temperature difference between the top of the rim and inside the canyon. Hikers can be surprised as they start with pleasant 70-degree temperatures at the top and approach a dangerous 100 degrees, or more, near the river.
Now the National Weather Service is working to address that gap in perceptions. With help from the Park Service, it installed two weather stations inside the Canyon: one at Indian Garden Campground, the other at Phantom Ranch.
When it comes to controlling the many non-native, invasive plants in northern Arizona, weed warriors call on every tactic in the book. As they seek to minimize the spread of a weed called diffuse knapweed, they’re turning to a tiny ally: a weevil that loves to eat knapweed seeds.
Diffuse knapweed is a low-growing shrub that originated on the Russian steppes. Since the 1980's, it’s taken over roadsides and pastures in the region. It’s a heavy seed producer and a tough competitor against native plants.