The changing of natural land into concentrated man-made landscapes – aka urbanization – is leading to some dicey problems. Increasing the area people have influenced means patches of natural landscapes are left behind. These patches are called habitat fragments. By creating these habitat fragments we are isolating the organisms that live in them. An isolated habitat makes life even more complicated and can lead to habitat degradation and biodiversity loss.
The rate at which we are changing our environment, mainly in the form of urbanization and unsustainable use of resources, has enormous trickle-down consequences. With climate issues only worsening, we must restore ecosystems and the environment to protect ourselves and the other organisms on our planet. But how can we determine what areas are most at risk to direct conservation efforts more effectively? We can examine how change affects the environment by looking at edge effects and indicator species.
Edge effects reveal how change affects an ecosystem.
As the natural world becomes smaller due to urbanization, new interactions happen at the intersection of natural and man-made landscapes. When two different habitats come together, things change at the edge of these landscapes. The edge between intersecting habitats can act as a barrier to movement, harm organisms, and give way to different interactions that would not have otherwise occurred. The ways that an ecosystem can be influenced when habitats intersect are known as edge effects. Essentially, edge effects are the consequences that befall plants and animals when one habitat conjoins with another.
Edges of habitats can give insight into species composition, structure, and function of the entire habitat while also having their own unique species and characteristics. Edges may affect the organisms in a habitat fragment by changing abiotic (physical and non-living, like soil quality or amount of sun) and biotic (living, like diseases and food availability) conditions. Things like species interactions, desiccation, changes in plant growth, and competition, are some of the changes that can happen when two dissimilar edges of habitats come together. As a result, ecosystem dynamics can change drastically due to edge effects.
An organism’s physiological tolerance to the conditions on and near the edge determines if it can withstand the changes. This further reduces the livable part of a habitat fragment making the effects of urbanization more dire. Imagine an area is logged and now the edges of the habitat don’t have as much shade cover. This can then make the edges unlivable for species that can’t live in warmer temperatures. Understanding edge effects can help mitigate things like microclimate shifts, habitat instability, and species loss.
Indicator species reveal if ecosystems are changing.
Within habitats are species, or groups of species, that can reflect the biotic or abiotic state of the environment. They give insight into the evidence for and impacts of environmental change. They can also give insight into the diversity of other species, groups of organisms, or entire communities within an area! Because of this, these plants or animal groups can reflect the environmental health of an ecosystem. They, therefore, serve as a way to measure environmental conditions that exist in a given area.
Indicator species can be used to detect pollution, monitor conservation efforts, and gather information on environmental changes from local to global scales. Indicator species can also be used to make inferences about climate change because of how influenced they are by their environment. Essentially, the presence of certain species of plants and animals suggests how well other species may live in the same place and can demonstrate the effects of change in a habitat.
For example, mosses can show the acidity of soils and can tell us what types of plants could survive as a result. Amphibians are very sensitive to environmental changes and can provide early warnings of decreased water and air quality. Crustaceans are tested for heavy metals, pesticides, and plastics to gauge the effects of agricultural runoff and other water pollution issues. Wetland mammals like manatees, beavers, and river otters can also give evidence for potential habitat degradation when you study their population size, reproduction rates, and general health.
Edge effects and indicator species are important gauges for conservation.
The interactions between organisms that live in an area are deeply complex and intertwined. For example, the plants of an area determine what herbivores can live in the same space! Due to the huge influence humans have had on the environment, we are changing how these organisms can interact. These interactions aren’t always understood, but for the sake of conservation, figuring out how to measure change in an area is vital.
As we take over more of the environment, we create pockets of livable habitat for plants and animals. Because of this, it’s important to understand how our proximity to these habitat fragments influences what lives in them. It’s also important to realize what creating these fragments also does. From these points of research, we gain species-occurrence data that provides useful information that can help determine species risks and areas that need to be prioritized.
Until we as a society reprioritize the health of our environment, we as individuals can reintegrate nature into our urban landscapes. You can do this through things like native plant gardens, creating pollinator habitats, and leaving water out for birds as a way to foster native diversity. Overall, we need to continue understanding the effects we have on the environment and realign ourselves with nature to stop environmental decline before it’s too late.