Many living organisms interact with each other, and the environmental factors around them to produce a living, thriving ecosystem. Within an ecosystem, every organism has a specific habitat and niche, that allow them to interact and facilitate in the ecosystem functions of transfer of energy (food chain and food web) and cycling of nutrients. An ecosystem survives better if it has a greater species richness and diversity, because this allows it to accommodate more environmental disturbances.
The progressive question from this point is- do the many ecosystem on Earth function in isolation? Or are they interconnected?
While an ecosystem can function quite well on it’s own, that is not how nature decided to work. Ecosystems are connected. The functioning of ecosystems are intricately woven with how far or near they are to each other, what kind of landscape they live in (forest land, river bank etc) and how these landscape define their interactions.
It is to address our scientific curiosity regarding this aspect that the discipline of landscape ecology evolved. Landscape ecology is the study of spatial patterns, it’s change over time and how it affects the populations and communities it supports. This study is unique because it is usually done on a large scale, ranging in hundreds of meters or a few kilometers.
During the 1980s, scientists began to become certain that ecological processes can extend over huge areas. Let’s take an example.
Two forests, separated by a river can be considered two separate ecosystems. That is because most terrestrial organisms (plants and animals) living in a forest are unlikely to cross the river and enter the other forest. Nevertheless, very clear examples of interaction exists between these two ecosystems. Wind pollination could result in transfer of genetic material between the plants of the forest, despite being geographically separated (called metapopulations). Similarly, birds are not constricted by the presence of a river. Their movements between the two forests brings about mixing of the food chain between the two forest ecosystems.
Similarly, animals like Elephants have a tendency to traverse huge areas (landscape scale) in search of food, and other biological activities. This movement is an important part of their lifestyle. (They tend to occupy the same niche in different ecosystems).
Other examples of inter-ecosystem interactions include forest succession and large scale natural disturbances.
Landscape ecology- The human element
Traditionally, ecology never took into effect the dominant role played by humans. Humans have a massive influence on the flow of energy, nutrient cycling and the evolution of ecosystems. This influence is not balanced by nature, which is why we are causing such havoc in today’s environment. We can no longer ignore these impacts while studying ecology. Landscape ecology has evolved to include the study of human interactions on broad spatial scales like deforestation, agricultural practices, flow regulation of rivers, habitat fragmentation.
The whole outlook of natural ecosystems has changed because today, we have very few pristine ecosystems left. Humans have affected most ecosystems and biomes on the planet.
The scope for landscape ecology
Landscape ecology, while an important tool in understanding inter-ecosystem dynamics, also is extremely important for studying the human impact on the environment. Many of the current issues in ecology, like changing flood regimes, land degradation, extinction, changing community structures are all a result of human intervention on a large scale. Landscape ecology addresses how to manage populations of animals and species, how to mediate habitat fragmentation, how to plan human settlements in disaster-prone areas, among other things.
The loss of biodiversity and richness in the world is largely due to landscape level impact of human activities. In continuation with my posts on Biodiversity, I will take a closer look at how ecosystems interact between themselves, and the role humans have played in these interactions.
- Kevil McGarigal, Introduction to Landscape Ecology.