Ira Wallace ambles around the butcher block countertop in the kitchen she shares with a community of farmers in central Virginia. She has separated a single leaf from the large baskets of unusual, parti-colored collard greens she got from a friend’s farm. Its creamy-white veins stretch upward across the green leaf, narrowing as they reach purple-tinged tips.
“Purple is a color that develops in the winter much more strongly,” Wallace explains, as she probes the frost-damaged leaf. “But look at that color! And that’s anthocyanins. They’re supposed to make you healthier.”
These aren’t commercially produced collard greens typically sold in supermarkets or restaurants. Many of the heirloom varieties Wallace and her friends grow are rare, some once teetering on extinction. Other types can likely be found in backroad gardens of aging stewards, but countless varieties have vanished in the U.S.
There was once a kaleidoscope of diversity in collards, as people diligently collected and replanted seeds, passing them from one generation to the next to preserve the qualities they found most important. Collards — an inexpensive, nutrient-rich vegetable — became a staple for many Southern families, especially African Americans trying to feed their families healthy food year-round.
According to a landmark new study, 102 million hectares (Mha) (252 million acres) of land — an area the size of Egypt — have been converted to crops since the start of the 21st century. To put this into perspective, while it took more than 8,000 years for humanity to convert 1.1 billion hectares (2.8 billion acres) of nature into cropland by the year 2000, it took a mere 20 more years to expand this area by another 10%.
These findings come from the first-ever high-resolution maps of global cropland extent and change during the 21st century, recently published in Nature Food by researchers from the University of Maryland and now available via the Land & Carbon Lab. The researchers defined “cropland” as land used for annual and perennial herbaceous crops for human consumption, animal feed, forage (including hay) and biofuel. The definition excludes pastures and rangelands, shifting cultivation and tree crops such as fruit orchards, coffee, cocoa, oil palm and rubber.
These satellite-based findings are troubling news for climate and biodiversity, since much of the expansion comes at the expense of forests and other natural ecosystems. Of course, food crops are critical for feeding a growing global population. But to keep global warming below 1.5 degrees C and curtail the 6th great species extinction, increases in food production needs to be decoupled from ecosystem conversion.
Financial institutions around the world can now measure the positive impact of their investments into biodiversity conservation, adaptation, mitigation, forest protection and sustainable livelihoods with the help of a new indicator directory and resources platform, launched today.
The Land Use Finance Impact Hub and its Positive Impact Indicators Directory – launched today by UN Environment Programme (UNEP) Climate Finance Unit and the UNEP World Conservation Monitoring Centre (UNEP-WCMC) – has been developed with and for impact funds and sustainably focused financial institutions, and aims to support the rollout of effective industry frameworks to track the environmental and social impacts of land-use investments.
For millennia, North American ecosystems benefited from fire, mostly set by Indigenous people. Now, a movement is growing, particularly in the eastern U.S., to reintroduce controlled burns to forests and grasslands and restore the role of fire in creating biodiverse landscapes.
From catching poachers to documenting species to saving lives, guardians all along the B.C. coast are bringing back traditional practices of territorial safeguarding — and filling major knowledge and conservation gaps while they’re at it
From the “boing” of a minke whale to the “drum” of a red piranha, scientists are documenting more sounds in our world’s oceans, rivers and lakes every year. Now, a team of experts wants to go a step further and create a reference library of aquatic noise to monitor the health of marine ecosystems.
The Global Library of Underwater Biological Sounds, “Glubs”, will include every “thwop”, “muah” and “boop” of a humpback whale as well as human-made underwater sounds and records of the geophysical swirl of ice and wind, according to a paper in the journal Frontiers in Ecology and Evolution.
As conservationbiologists familiar with these clashing viewpoints, we wondered whether there was room for a more nuanced strategy than the typical yes/no standoff. In a recently published study, we used camera traps at hundreds of sites across Washington, D.C., to analyze the predatory behavior of urban free-roaming cats. The cameras recorded all cats that passed them, so our study did not distinguish between feral cats and pet cats roaming outdoors.
Our data showed that the cats were unlikely to prey on native wildlife, such as songbirds or small mammals, when they were farther than roughly 1,500 feet (500 meters) from a forested area, such as a park or wooded backyard. We also found that when cats were approximately 800 feet (250 meters) or farther from forest edges, they were more likely to prey on rats than on native wildlife.
Since the average urban domestic cat ranges over a small area – roughly 550 feet (170 meters), or one to two city blocks – the difference between a diet that consists exclusively of native species and one without any native prey can be experienced within a single cat’s range. Our findings suggest that focusing efforts on managing cat populations near forested areas may be a more effective conservation strategy than attempting to manage an entire city’s outdoor cat population.
Cats on the loose
Free-roaming cats are a common sight in Washington, D.C., which has a feline population of 200,000. Like many cities, Washington has had its share of cat management controversies.
Professionals on either side of the free-roaming cat debate largely agree that cats are safest when kept indoors. An outdoor cat’s lifespan generally peaks around 5 years, compared with 10 to 15 years for an indoor cat. Free-roaming cats face numerous threats, including vehicle collisions and contact with rat poison. Acknowledging these risks, most animal welfare organizations encourage an indoor-only lifestyle.
Similarly, there is little disagreement that cats hunt; for centuries humans have used them for rodent control. But invasive rats, which are often the target of modern rodent control, can grow too large to be easy prey for cats. In response, cats also pursue smaller species that are easier to catch. Studies have linked cats to 63 extinctions globally and estimated that cats kill 12.3 billion wild mammals annually in the U.S. alone.
Disagreements arise around handling cats that already live outside. Population management programs often utilize trap-neuter-return, or TNR – a process in which cats are trapped, spayed or neutered and re-released where they were caught.
In theory, TNR limits population growth by reducing the number of kittens that will be born. In reality it is rarely effective, since 75% of individual cats must be treated every year to reduce the population, which is often not feasible. Regardless, reproduction itself is not what most worries conservation biologists.
Today the Earth is losing wild species at such a rate that many scientists believe it is experiencing its sixth mass extinction. In this context, free-roaming cats’ effects on wildlife are a serious concern. Cats have an instinctual drive to hunt, even if they are fed by humans. Many wildlife populations are already struggling to survive in a rapidly changing world. Falling prey to a non-native species doesn’t help.
Since cats are generalist predators, their wild-caught diet tends to reflect the local species that are available. In areas with more birds than mammals, like New Zealand, birds are cats’ primary prey. Similarly, cat diets in the most developed portions of cities likely reflect the most available prey species – rats.
While cats top the list of harmful invasive species, rats aren’t far behind. In cities, rats spread disease, contaminate food and damage infrastructure. There aren’t many downsides to free-roaming cats preying on rats.
City centers have no shortage of rats, which can live anywhere, including parks, subways, sewers and buildings. But native animals tend to stay in or near areas with sufficient outdoor habitat, like parks and forested neighborhoods. When cats hunt in these same spaces, they are a threat to native wildlife. But if cats don’t share these spaces with native species, the risk declines dramatically.
Conservation funding is limited, so it’s critical to choose effective strategies. The traditional approach to cat management has largely consisted of attempting to prohibit cats from being loose altogether – an approach that’s incredibly unpopular with people who care for outdoor cats. Despite calls for outdoor cat bans, few have been enacted.
Instead, we suggest prioritizing areas where wildlife is most at risk. For example, cities could create “no cat zones” near urban habitats, which would forbid releasing trap-neuter-return cats in those areas and fine owners in those areas who let their cats roam outdoors.
In Washington, D.C., this would include forested neighborhoods like Palisades or Buena Vista, as well as homes near parks like Rock Creek. As we see it, this targeted approach would have more impact than citywide outdoor cat bans that are unpopular and difficult to enforce.
Hard-line policies have done little to reduce outdoor cat populations across the U.S. Instead, we believe a data-driven and targeted approach to cat management is a more effective way to protect wildlife.