The relationships that exist between species within a community are often what hold ecosystems together whilst maintaining a relatively stable state. If these relationships are disrupted there is a reasonably high probability that the community will become destabilised and possibly even crash. However, the relationships between species within a community can be relatively complex and so ecologists often use food webs to describe and model these relationships.
Food webs have many uses in both theoretical and applied ecology. For example they provide insight into which species fall into which trophic level (i.e. producers/autotrophs, consumers, decomposes) and they can identify keystone species which generally have great ecological and conservation importance to the community’s overall functioning.
However, food webs are often not entirely linear – that is they are not simply grass \(\rightarrow\) wildebeest \(\rightarrow\) lion \(\rightarrow\). Rather there may be several producers, consumers and predators which often depend on the same suite of resources. Furthermore, it may be that although it appears that a consumer is having a negative impact on a lower trophic level, these negative impacts are important for maintaining and possibly even promoting the abundance of the consumed species. Another thing to consider is the effect that the removal of one species with no apparent direct connection to another species could over time drastically impact the other species through indirect effects.
There are several different ways to represent and communicate the many relationships that exist between species within a community using food webs. Each type of food web is designed to provide a different kind of insight into the community. Broadly, ecologists break food webs up into “green” and “brown” food webs. Green food webs are those which the primary energy source are autotrophic photosynthetic creatures whilst brown food webs are those where the primary energy source is decaying matter or detritus.
There are also several different kinds of relationships that ecologists highlight with food webs - four common types of food webs are
Based on the topics introduced above you are required to write an essay of approximately 1000 – 1200 words (approximately 2 pages excluding references). In this essay you should introduce and discuss
Conclude your essay by speculating about the future of food web ecology as a discipline - will it be a useful discipline to pursue, what kinds of questions will it be able to help ask/answer, and how/whether this discipline will contribute towards the conservation of endangered or sensitive communities. Structure your essay as a literature review so that it includes
Total marks - 65