Field Naturalist
When I look out over the meadows at Gilsland Farm today, it’s hard to not think of what was. From May to September, the sanctuary was a Monet painting: verdant hills peppered with yellow goldenrod and purple thistle, bustling with metallic beetles, colorful butterflies, and flowerflies patterned like vibrant Rorschach tests. Now, it’s brown. At home, we might be inclined to prune our sad pothos, rake the fallen leaves, toss an old bouquet… in nature, however, dead foliage isn’t an intrusion. It’s part of the story. In an effort to soothe my wistfulness for summer, here is a mini treatise on dead, brown, shriveled plants—the what, the why, and the abundance of life (and beauty!) in all those earth tones.
Most broadleaf plants are pretty brown by now. Frost damages cell walls of herbaceous plants when water in their tissue freezes into sharp ice crystals. When this happens, the tissue turns brown. What we’re seeing is oxidization, like on a cut apple. The enzymes that cause this reaction are called Polyphenol Oxidases (PPOs). While the plant is alive, PPOs play defensive roles in plants, protecting them from bacterial and fungal pathogens as well as insect predators. When cell walls are compromised, these PPOs mix with other chemicals in the presence of oxygen. This reaction is called enzymatic browning. Brown foliage is the final salute of chemicals that keep plants alive and well during the growing season.
To a sparrow (one of those frustrating “little brown jobs,” as they’re affectionately called by birders), those brown plants are critical camouflage. Hundreds of White-throated, Song, Lincoln’s, Swamp, White-crowned and Savannah Sparrows have kept my binoculars glued to my face this fall. Granivores (grain eaters) need to spend a lot of time foraging because seeds are small, scattered, and are usually less nutrient-dense than insects. Brown plumage doesn’t catch the eye precisely because it’s such a ubiquitous color in the landscape. These birds evolved to blend in with their foraging habitat so that they can spend less time looking out for predators and more time gathering the calories they need. To millions of migrating and wintering birds, a crispy brown meadow is an oasis, providing shelter, as well as food for the journey ahead.
To these birds, a wilted brown meadow is a bounty. Brown seed coats signal that the plant is no longer photosynthesising and seeds are mature. All of that vibrant green earlier in the year was chlorophyll slurping up sunlight, turning it into all of the things that make up a plant, including, and perhaps most importantly, seeds. The colorful flowers that we love existed entirely for seed production. Vibrant petals invited insects to gather pollen from yellow stamens and deposit it on pistils. If fertilized, the ovules at the base of those pistils swelled into little embryos tucked into protective hulls and nourished by an endosperm. Those brown seeds are the precious final products of the growing season. They’re also a nutritious prize for seed-eating animals. Native sparrows time their migration to coincide with the abundance of seeds available after blooms die.
What about other organisms? Finding beauty when everything is roughly the same color isn’t hard. It just requires taking a closer look at individual plants, animals, and textures. Here are some beautiful brown organisms we’ve found around Gilsland Farm this fall.
