Competition is the direct or indirect association among organisms, which can be either, be between the members of the same species or among those of different species. For example, it can be between plants and plants or animals and other animals or animals and plants, whereby the survival of one is threatened or lowered by the existence of another especially when there is a limited supply of some basic resources such as food, water, air and sun required by both. Therefore, the organisms compete for the little resources available for their fitness and thus their survival (Ammunét, Klemola, and Saikkonen,78).
The competition can be intraspecific or interspecific specific. In intraspecific is where the individuals of the same species compete for the same resources. For instance, some plant species grow taller than surrounding tree species in a thick forest to absorb more sunlight. So the tall trees receive more light than the shaded trees. While interspecific is where the members of different species compete for the same resources. The competition can be an Interference competition where individuals fight over limited resources but one species has a benefit over the other, resulting in a bigger loss by one rival. An example is where plants of one genus release poisonous chemicals that slow down the survival of other potential competitors. The competition can also be Exploitative where one type of plant reduces or uses a resource more efficiently thereby causing depletion for other species. An example is an aphid species that feed on host plant sap leaving less for competing species. Another type of competition is called apparent which occurs when two or more species in an environment affect shared ordinary enemies in the same habitat.
Plants compete for resources for either survival or better reproduction ability. The common resources competed for include habitat, water, sunlight, and nutrients. When these are sufficient, then the plants will compete to perform well by yielding the best products. In case the plants are close to each other, then the essential resources become scarce or limited which results in a competition confronting each other for a potential share. In some cases like the scrounging plants, they will fight for the nutrients owned by the host.
With the availability of sufficient nutrients such as water, nutrients, sunlight, and a proper territory for growth and survival, plants tend to compete against each other to demonstrate the highest production capacity than the other. For example, plants that produce a lot of seeds like blackjack plants have the best methods of spreading than plants that produce fewer seeds like mango. Also, plants with flowers that are attractive are pollinated faster by insects therefore better production as compared to the less attractive flowering plants. When the plants are in proximity they compete for nutrients, so they go on offense by trying to obtain as much as possible. In the process, the opponent plants use defensive methods such as the production of toxins, spreading of the roots, in order to get the required amount of nutrients and water for growth, existence, and reproduction.
Another example of offense and defense mechanism is exhibited competition for sunlight where some plants grow very broad leaves very fast to absorb more light at the expense of the nearby plants which grow at a slower rate. So, some of these plants can defend themselves by producing toxins that prevent other plants from getting close. The parasitic plant goes on the offense by trying to get the nutrients from the host as the hosts defend this by absorbing more nutrients for survival success. So if the host prevents the parasite from getting the nutrients it dies, and on the other hand, if the parasite takes a lot of nutrients then the host can obtain the host dies and so the parasite.
Different plants have different adaption mechanisms to various conditions while some have better survival tactics others have just moderate. In a change of a variety of conditions for example change in light regimes some plants will grow taller than the others as others will develop broader leaves as an offense to get more sunlight, and on change of nutrient concentration the shorter plants will develop and spread more roots as a defense thereby getting more nutrient at the expense of the taller plants which have long roots at this point they may slow the rate of growth, again on change of carbon dioxide the plants with broad leaves will absorb more than the plants with needle-like leaves. Therefore, if the change goes on like that then the competition will be very tough, therefore the offense and defense mechanism will continue for the fitting and survival of both species.
Climate change will favor some plants while others will not be favored depending on the type of change, for instance, only drought-resistant plants such as acacia can survive in absence of water as other plants starve and die. Again for some cases of excess water, only water plants can survive as others rot and die. For that matter, most plants have adaptation mechanisms that they apply when a situation arises.
Various species are not related to the richness and the relationship between is affected by competition for resources. According to the invasive paradox, it is possible for invasive species to have both negative and positive relationships with the other species. This paradox implied that the richness of certain species can play a role in the relationship between the invasive species and the exotic species. After using observations experiments and theoretical evidence, their relationship can be either negative or positive relationship in the context of native-exotic richness. However, none of these processes generated both. Fridley et al (2007) thus have concluded that the richness of native species will invite invasive species but the reduction of native species richness will accelerate the pace of invasion.
It has been found through a study by Lau (28) that the exotic plant Medicago polymorpha and the exotic herbivore Hypera brunneipennis changed the strength and direction of natural selection by causing changes in the competitive ability and anti-herbivore defenses of the native plant Lotus wrangelianus. When exotic herbivore Hypera had a majority presence, it caused increased resistance to herbivores in the native Lotus’ while the additional presence of Medicago ensured that this did not happen. Rather, selection on tolerance, which is another defense trait among plants increased in the presence of Hypera and Medicago. Thus, it can be said that invasive species have the potential to change the evolutionary paths of native plant populations (Lau, 29). According to a study by Capers et al (2007), it has been found that invasive species are not related to the richness of the native species. Capers et al arrived at this conclusion after studying the relationship between native and invasive species richness of submerged aquatic plants in and among 103 Connecticut lakes (Schweiger, Settele, Kudrna, Klotz, and Kühn 78). Schweiger, Settele, Kudrna, Klotz, and Kühn(8)have studied the invasion paradox according to which it is possible for invasive species to have both negative and positive relationships with the native species. This paradox implied that the richness of the native species can play a role in the relationship between the invasive species and the exotic species. After using observations experiments and theoretical evidence. Fridley, Stachohowiez, and Samuel Naeem (15) identified eight processes that showed an either a negative or positive relationship in the context of native-exotic richness. However, none of these processes generated both. Schweiger, Settele, Kudrna, Klotz, and Kühn (12) thus have concluded that the richness of native species will invite invasive species but the reduction of native species richness will accelerate the pace of invasion.
Works Cited
Ammunét, Tea, Tero, Klemola, and Kari Saikkonen. Impact of Host Plant Quality on Geometrid Moth Expansion on Environmental and Local Population Scales. New York: John Wiley, 2009. Print.
Fridley, John, James Stachohowiez and Samwel Naeem. “The Invasion Paradox: Reconciling Pattern and Process in Species Invasions”. Ecology, 2007
Lau, Jennifer. “Beyond the Ecological: Biological Invasions Alter Natural Selection on a Native Plant Species”. Ecology, 2008.
Schweiger, Oliver, Josef Settele, Otakar Kudrna, Stefan Klotz, and Ingolf Kühn. Climate change can cause spatial mismatch of tropically interacting species. Ecology, 2008.