Garden
For several years, I have investigated how the natural world manifests the nested complex dynamical systems of which it is composed. After producing work criticizing the hegemony of reductionism in biological science, I wanted to explore intact systems as an antidote.
This exploration began with the series Animalia (1994-1997), in which the system investigated was that of the intact animal body. In Interactions (2002), these bodies themselves became nodes in larger systems of interacting populations that formed new emergent patterns. Structure (2000) examined the way individual components self-organize into patterns that are similar over many scales. The emphasis in this earlier work was on general principles of complex dynamical systems.
By contrast, Garden looks at specific participants in the kind of relationships that form the communities which comprise the complex system we call the biosphere. For each work in Garden, I photographed, over a period of time, plants and their associates from my own and other gardens. By spending time with the plants, I could see and document their insect visitors, as well as resident organisms such as fungi, spiders, snails and fuchsia mites.
As soon as a garden is planted, interactions begin among the growing plants, and with other lifeforms: animals, fungi, and bacteria. Each organism may be fulfilling its own needs, but each affects and is affected by the others. Feedback cycles arise and behavior becomes coordinated. A new, emergent entity is formed, a garden, something greater than its group of parts, a community of interdependent organisms. Thus, a garden can be thought of as a model for the formation of complex dynamical systems by self-organization.
A common way to model complex systems is by use of a grid, such as those formed by the tile arrays in these works. In such a model, each unit (tile) represents a player in the system. Before a player can make a decision about the next action to take, it must consider the states of the nearby players. This kind of modeling can be used by ecologists to reveal patterns in certain natural communities precisely because it approximates the dynamics of real interactions.
I printed the images on tiles to evoke the idea of home, of the basic functions of eating, drinking, cleaning, of maintaining the order of life. Ecology literally means “the study of home” (ecos- = home, -ology = the study of). And the organisms in these images are at home in a fundamental sense. By bootstrapping into existence the biological communities on which all life depends, they are in fact creating their own homes and ours.
Works
For the two pieces that make up Annual Cycle (2005), I photographed a potted, miniature rose plant every week for a year. I observed two complementary growth cycles in this time. Flower buds repeatedly appeared, expanded into roses, and senesced. Leaves, abundant and fresh in spring, were skeletonized by sawfly larvae (which look like green caterpillars). When the soft leaf tissue was gone and the larvae therefore no longer present, the plant simply grew a new set of leaves. It continued to replace lost leaves throughout the year. Regrowth of foliage after loss to herbivores is the ultimate plant strategy for tolerating herbivory. Because the evolutionary history of plants is one of co-evolution with herbivores, there has never been a time when plants were not eaten, which has profoundly shaped the unique nature of plant life.
The Root Zone (2006) features organisms of the soil food web. Billions of bacteria and fungi feed on exudates and sloughed tissue from plant roots. They in turn are fed upon by protozoa and nematodes. Protozoa and nematodes are eaten by tiny insects and other arthropods which are eaten by larger insects, and so on up the size scale to more familiar slugs, centipedes, earthworms, gophers and other animals. A functioning soil food web locks up nutrients such as carbon and nitrogen in the bodies of these organisms, releasing them slowly as needed by plants. Because these lifeforms are small and live in the dark, they are difficult to see. Some I photographed alive, either in situ or excavated. I grew soil bacteria and fungi on nutrient agar and photographed the resulting colonies. To depict one kind of mycorrhizae, which are vital symbiotic root/fungus organs, I micrographed prepared, stained roots on microscope slides. I also photographed living ectomycorrhizae of pine roots being grown for a research project.
Guests (2004) depicts three garden plant species (rose, milkweed and fuchsia) with several of their insect and fungal associates, especially those that rely on the plants for food. Note that despite providing sustenance for herbivores, all these plants were able to survive and reproduce.
Three plant species (monkeyflower, phacelia and geranium) are featured in Helpers (2004). Most plants produce defensive chemicals to limit consumption of their tissues by herbivores, but many have also “learned,” evolutionarily, to broadcast a chemical message inviting carnivorous insects to feast on herbivorous “guests.” Ladybugs and syrphid flies (the larval stage) are two such carnivorous species.
The images in Corollas (2004) are predominately of insects and fungi associated with the flowers in a garden of snapdragon, evening-primrose, agapanthus, penstemon and dahlia. (The term corolla refers to the aggregate of petals on a flower, especially if those petals are joined into a cup or tube.) Of note here is the presence on two plant species of little brown globes called aphid “mummies.” These are the expanded shells of aphids which were consumed from the inside by larvae of tiny parasitoid wasps. The adult wasp lays an egg inside an aphid. The aphid stops feeding and itself become food for the larva that hatches from the wasp egg. The presence of the larva causes the exoskeleton of the aphid to expand and harden. After the larva pupates inside the mummy, the new adult wasp cuts an exit hole in the mummy, emerges and continues the cycle.
Milkweed plants support a surprising variety of insect species, as seen in Mother’s Milk(weed) (2005). Although the milky juice of the plants is toxic to many herbivores, some species, such as the monarch butterfly, the milkweed bug, and the oleander aphid, have, through long evolutionary association, come to actually depend on this plant. Indeed, the larva of the monarch can eat nothing else.
In Bread of the Biosphere (2005), leaves from such common garden plants as tomato, squash, strawberry, cucumber, and sunflower are feeding other lifeforms. The major function of leaves is to synthesize carbohydrates using solar energy. Unlike stems and roots, leaves cease growth at maturity. After a period of peak sugar production, they senesce and die. During senescence, the stem extracts useful compounds from the aging leaves. When this process is complete, the leaves simply drop off. This shedding is not accidental; a special cell layer at the base of the leaf stalk has evolved for just this purpose. If plants have to play the role of primary producer for the rest of the biosphere, the expendable leaf is the ideal sacrificial organ.
With Food (2005), I specifically include humans as another animal dependent upon plants for existence. Our food plants give us protein, carbohydrates and oils, compounds we need for building and fueling our bodies. They incidentally provide us with vitamins, minerals, and antioxidants, originally used by the plants themselves. We naturally prefer to be the sole herbivore in our food gardens, but we usually end up sharing. In fact we inadvertantly encourage other consumers because the plants that taste good to us are low in the defensive chemicals that would normally deter feeding by other organisms.
The culmination of the food garden (Fruition, 2006) is the harvest of tomatoes, peppers, grapes, squash and other yummy “vegetables.” Because these “vegetables” have seeds, botanically they are fruits, developed from the ovaries of flowers. Fruits are thought to have evolved in concert with animals as a way for stationary plants to get their offspring to new locations. The animals eat the highly nutritious fruits but the seeds pass through their digestive tracts intact. The seeds are eventually deposited with a blob of fertilizer somewhere away from the parent plant. Both parties benefit. We and our food plants employ the same mutualistic agreement (although the method of seed distribution is different). We select the plants we like (for instance, those that are the biggest, or the most flavorful, or that ripen earliest), then deliberately propagate those plants. So like their wild relatives, our food plants effectively use their animal “predator” to increase their own populations.
Transubstantiation (2006) completes the garden cycle. What we call “decay” is simply the process of plant bodies being transformed into bodies of microbes. Even before transubstantiation of the entire dying plant, portions of the plant that have served their purpose become substrate for fungi and bacteria. If tissue is dying, such as the spent petals on a squash plant, it is simultaneously becoming other lifeforms. Without transubstantiation, dead bodies would quickly tie up normally recycled molecules, and the cycles of birth and death would end in stasis.
In The Theory of Evolution (2006) aphids on hibiscus are consumed by ladybug larvae before they inflict fatal damage. Plants, aphids and ladybugs share a long evolutionary history. But the exotic giant whitefly feeding on hibiscus, smothers the plant with waxy secretions. The giant whitefly is out of its natural community. Organisms that evolved to consume it are missing here, so the whitefly population explodes. The gulf fritillary caterpillar eats only the poisonous passion flower plant. The caterpillar has evolved to resist the toxin by sequestering it in its own body to use for its own defense; thereby, it has the food resource all to itself. Some fungi, such as powdery mildew, inhabit and consume plants, but plants have evolved resistance to limit the damage. In another evolutionary dance, flower structure and color evolve with pollinator structure and behavior. Long-term ecological interactions result in the co-evolution of the participant species.
Carol Selter
2005/2008