By Chelsea Jandreau, Education Director
On a Saturday morning walk with a group of families around the ponds at Audubon Community Nature Center, there was plenty of activity to see if you were willing to stop and look for it. The Red-backed Salamanders were crawling around under logs and wet leaves, the muskrats were swimming up to shore and nibbling on grass, and Tree Swallows were swooping through the air above the pond catching bugs and laying claim to the nest boxes.
At first these three animals seem largely unrelated. They’re different classes of animal, they occupy different spaces, and eat different things. However, they are part of the same larger community in the wetlands of Audubon. An ecological community is a lot like a human community in that it is a group of living things interacting and occupying the same general space. It can be a small, local community or a larger, regional community, but either way, there are different jobs getting done and a whole host of interactions occurring amongst the residents.
In many cases, the species within a community are indirectly connected, like our muskrats and swallows. They both live in wetland and pond ecosystems, but they don’t interact directly and they aren’t competing for the same spaces or food. They fill a different niche.
A niche is just the specific role and space an organism or species occupies in its environment. Muskrats are herbivores who spend time in the ponds and on shore, while Tree Swallows eat insects and bugs, and fly above the pond, landing on branches. Despite their differences, they are still both important to the ecosystem as a whole, and they can each make the habitat and ecological community a healthier and more diverse place to live.
There are plenty of cases where certain species are in direct competition and have a greater impact on each other. Our Tree Swallows were competing amongst each other to claim the nest box, but they also compete with other cavity nesters, like Eastern Bluebirds, for nest boxes and natural tree holes. They are both primarily insect eaters, but swallows catch their food in flight, while bluebirds typically find their food on the ground. So, the nest boxes over water usually go to the swallows, but the ones in fields near the ponds are definitely a point of contention. Once we have a winner, then comes the relationship of parents and babies. Baby birds are raised by their parents until they fledge, where they are then shortly sent on their way. Other animals, like bears, can spend multiple years with their children before the next generation moves on. Some species raise their young communally, while other species lay their eggs and the babies are born immediately fending for themselves.
Competition is one type of relationship within an ecological community, but there are plenty of ways species can interact. And as with all communities, sometimes these relationships help and sometimes certain aspects hurt. Any given habitat has a mix of symbiotic, predatory, and parasitic relationships.
Symbiotic relationships come in a couple varieties. Perhaps both species are benefiting, or maybe one species in benefitting and the other one is unaffected. Mutualism is the term for a relationship where both species benefit. One of the best examples of this is between pollinators and flowers. Bees, certain beetles, and hummingbirds eat the nectar produced by flowers and along the way they pick up sticky, yellow pollen. As they move from flower to flower, they drop some of this pollen, helping the flower reproduce. Commensalism occurs when one species benefits from a relationship, but not at the expense of the other species. In many aquatic habitats, there are species that eat the algae off of other animals who don’t mind. At Audubon, you can also find another symbiotic relationship between two tiny insects: aphids and ants. The aphids eat sap from plant stems and excrete a sweet liquid called honeydew. The ants feed on the honeydew and in return protect the aphid colonies from predators.
Then there are the relationships where one organism is clearly benefitting but is causing harm to another organism. This is referred to as parasitism. Ticks are considered a parasite, even if the harm they do is not intentional. They feed on the blood of animals, including humans, and can transmit Lyme disease and other viruses into the bloodstream. However, there are also plenty of animals that eat ticks, so even though they cause harm to some, they benefit other animals.
Some animals take a more direct approach and intentionally harm another organism for their own benefit. Tiny parasitoid wasps lay their eggs in the body of certain aphid species. The egg hatches inside the aphid’s body and the larva feeds on the aphid, eventually killing it. Though less common, larger animals can also be parasitic. Brown-headed Cowbirds are brood parasites. They lay their eggs in the other bird’s nests, removing or damaging the host species’ eggs. Even after hatching, the cowbird babies are loud and mature quickly, causing the unwitting parent to raise the cowbird offspring at the expense of their own.
Predation is a relationship most everyone is familiar with. Red-backed Salamanders, even the littlest one we found on that Saturday hike, are both predator and prey. There are some predators at the top and a few prey that sit firmly at the bottom, but many animals fill a niche somewhere in the middle of multiple food chains. Red-backed Salamanders eat a variety of invertebrates, but they are also food for birds, snakes, and small mammals.
From the smallest, single-celled organisms to the largest mammal, each organism contributes to the continued functionality of its community. Organisms are both working together and working for themselves, directly and indirectly affecting the environment around them. Even though humans sometimes wonder if we would be better off without that plant or bug, each native organism contributes to the diversity and richness of the community.
Audubon Community Nature Center builds and nurtures connections between people and nature. ACNC is located just east of Route 62 between Warren and Jamestown. The trails are open from dawn to dusk and birds of prey can be viewed anytime the trails are open. The Nature Center is open from 10 a.m. until 4:30 p.m. daily except Sunday when it opens at 1 p.m. More information can be found online at auduboncnc.org or by calling (716) 569-2345.
Featured image: Red-backed Salamanders hatch out in their fully formed adult stage and begin looking for food and a safe place to hide.
Recent Comments