In every ecosystem, each living organism (plant, animal or microorganism) has a certain place where it lives. Some organisms live on land while others live in water. The location or environment where an organism normally dwells is called its habitat. The definition of a habitat can further be described as the place living things usually live, eat and breed in.
When habitats are grouped together, they form an ecosystem, defined as a community of organisms that interact with themselves and with their environment. In other words, a habitat is a place where an organism makes its home in any natural ecosystem and in order to survive, every organism has developed a capacity to adjust itself to its habitat. Habitats are quite dynamic and change at varying rates hence, any rapid changes can cause problems for those species with special adaptations only suited to a particular habitat.
A habitat meets all the environmental conditions an organism requires to survive. For example, a good habitat must provide everything an animal needs to find and gather food, select a mating partner, and reproduce successfully. In the case of a plant, that entails the right blend light, soil, water, and air. An example is thedesert thyme which thrives in the Sahara Desert. This plant does not use much water in the creation of its stalks, leaves and flowers, and it doesn’t need much water to maintain them. The desert thyme is adapted to surviving desert conditions (dry climates, sandy soil, and bright sunlight) and would not thrive in wet, cool areas with a large amount ofovercast (shady) weather, like the tropical rainforest.
Violent events (such as a wildfire, an earthquake, the eruption of a volcano, a tsunami, or a change in oceanic currents) may lead to changes in habitats over time.Alterations in a habitat may also occur more gradually over hundreds of years with changes in the climate and as different weather patterns bring variations of precipitation and solar radiation. Other changes may take place as a direct result of human activities, such as deforestation, the plowing of old grasslands, the construction of dams andrerouting of rivers, the draining of wetlands and the dredging of the sea/river bed. The deliberate or fortuitous introduction of exotic plant, animal or microbial species may have a devastating consequence on native wildlife, through increased predation, competition for available resources or through the introduction of pests and diseases to which the native species are susceptible to or have no immunity. In this chapter, the habitats of different organisms as well as how they survive and thrive in their particular habitats are highlighted.
COMPONENTS OF A HABITAT
Shelter, water, food, and space are the main components of a habitat,and these have to be in the correct proportion for a habitat to have a suitable arrangement. Occasionally, some components of a suitable arrangement can be met by a habitat, but not all.For instance, a lion’s habitat could have the right portion of food (antelope, goats, gazelles and rabbits), water (a pond, river, or stream), and shelter (trees or dens on the forest floor). However, the habitat of the lion would not be said to have a suitable arrangementif there is lack of space for the largebeast of prey to institute its own territory. Dwindling habitat space is usually the case for such animals when humans push them into an area too compact for it to survive due to expansion of homes and businesses.
The volume of space required by an organismto thrive differ widely among species. For example, the Cheetah is a territorial predator that needs a large amount of space to hunt and find a mate. The female leads a nomadic life searching for prey in a large expanse of land while the males are more sedentary. In contrast, the common carpenter ant needs only a few square centimeters for its entire colony to dig tunnels, find food, and carry out all the activities required for survival. In comparison, a cheetah will not survive in the same amount of space that a carpenter ant needs.
Likewise, plants need space to thrive. For instance, the African baobab is known both for their height and the girth of their trunk. It forms a very thick and wide trunk and mainly branch high above the ground. The spread of the roots actually surpasses the tree’s height; a factor that enables it to survive in a dry climate. In a typical community park or yard, a tree that huge would not have sufficient space to grow and thrive. It is worth noting that the term ‘space’is different from ‘range’ in that the range of an animal is the region of the world where its habitat is located. For example, the desert is the habitat of the camel, but the animal’s range include the Horn of Africa, the Sahel, Maghreb, Middle East andSouthAsia.
Another crucial aspect of a habitat’s suitable arrangement is accessibility to food. For example, it would no longer be a suitable arrangement if due to drought, food is not available to animals. They will obviously not have enough to eat even when they have unfettered access to space (large expanse of land), shelter (caves, forest floor), and water (streams and lakes).
Likewise, excess food in a habitat can also disrupt its balance. For example, a rapid increase in concentrations of nutrients like nitrogen and phosphorous results in algal ‘blooms’, a rapid proliferation of algae in freshwater habitats. Algae is an aquatic microorganism that synthesizes its own food via the process of photosynthesis. The algal bloom can affect the aesthetics of freshwater bodies by discolouring the water, turning it green, red, or brown. When the bloomed algae dies, the decaying biomass can result in oxygen depletion thus, destroying the habitat of organisms like fish and plants. In other words, availability of excess nutrients for algae can destroy its habitat’s food chain.
Water maintains and links all ecosystems on the earth. Every habitat must have some form of a water supply since it is essential to all forms of life. The main function of water in any habitat is to propel the growth of plants, supply the nutrients and minerals needed for the sustenance of physical life, provide a permanent home for organisms that live within it, or serve as a temporary dwelling or breeding grounds for many amphibians, insects and other animals that are birthed in water. As the most important nutrient in nature, living things need water to survive. However, some organisms require a lot of water, while others need very little. For example, the Arabian camel can travel for 161 kilometers while carrying goods and people without a drink of water. These mammals have a suitable arrangement for water conservation and long journeys without needing to drink much water in a hot, dry desert environment with very little access to water. On the other hand, the swamp hibiscus is a plant that needs lots of water and only performs well along pond edges, stream banks or other damp area, hence the suitable arrangement of this plant’s habitat depends on water.
Any place where an organism finds safety and refuge is a shelter. It is a place of sanctuary that protects it from predators and weather elements such as wind, rain and sun. A shelter also provides a space for sleeping, eating, hunting, and raising a family. Although an acceptable habitat would probably include a good shelter/home, the two are not synonymous.
In a habitat, there are many forms of shelters. For instance, a single tree in a forest can accommodate different shelters for various organisms. For a caterpillar, shelter could be the undersurface for the tree’s leaf. The cool, damp area of the tree’s bark might be the shelter for the lichen, while for the kite, shelter may be a high perch to build a nest and look out for prey.