My Science School

Wildfires are a natural phenomenon that have both advantages and disadvantages. Globally, they have played a crucial part in our ecosystems they wipe out creatures unfit for survival and help in the growth of resilient ones, they allow for the clearing of dead plants and ensure new plants grow instead, help a species move into a new territory and establish a population there, and so on. On the other hand, they can help invasive species flourish, push threatened species to the brink of extinction, cause irreversible damage to ecosystems, etc. And, over the last few years, it appears that across the world, the perils of wildfires have far outweighed the benefits they offer.

The Australian wildfire of 2019-2020 was in the news for the unprecendented destruction it left in its wake. It killed or displaced nearly three billion animals, making it one of the worst wildlife disasters in modern history. And now Canadian wildfires too are a cause for alarm. This wildfire season - the worst in Canada's recorded history-has destroyed millions of acres in the region, turning the focus on the nearly 700 species at risk. Some of these are even more at risk. How so? The habitats of a few species are already small. For instance, the half-moon hairstreak butterfly. Found in just a few small patches in Canada, these butterflies lost a part of their population and habitat to a lightning strike in 2017. Scientists are worried that such species could be lost completely if their habitats are destroyed in wildfires. Another species of concern is the burrowing owl that nests in prairie grasslands - affected by wildfires. Captive breeding programmes are being considered for both these species in peril. Further, the fire season has "overlapped with the breeding season for many species, presenting a clear danger to newborns". While adults and healthy individuals can move fast and find ways to escape, the same cannot be said of young ones. In addition, smoke from the wildfires travel far, with potential to harm many species, including migrating birds.

As mentioned earlier, wildfires have occurred naturally. But today, human-induced climate change and global warming have given way to changed rainfall cycles and drier conditions. This has pushed up the intensity and instances of wildfires. As a result, forests that once withstood wildfires are no longer able to do so, and this could eliminate or negatively alter ecosystems.

Picture Credit : Google 

 

Competition occurs everywhere, be it among peers or siblings. Even in the wild. Competition in the ecology is considered a negative interaction and happens when resources are limited. An ecological interaction in which competition occurs between members of the same species, as they compete for limited resources (for survival and reproduction), is called intraspecific competition.

This occurs when the niches overlap, that is, when the members use the same resources and the resources become limited. In the case of animals, the resources induce  food. water, territory and mates. For plants, the resources they compete for include light, water, root space and minerals.

Competition can be categorised into two-intraspecific and interspecific. The former occurs between individuals of different species. The latter, as explained, occurs between individuals of the same species. And as such, this competition is more intense as they are competing for the same niche! Here the animals are using the same resource which is in limited supply. And the better the competitor, the better are the chances of survival.

This form of competition can further be classified into scramble and contest. Scramble competition is when individuals depend on declining available resources even as the number of competitors increases. This is an indirect form of competition. The contest or interference competition is rather a direct form of competition and here the competitors defend the resources from others.

What happens to a species when there is intraspecific completion?

Intraspecific completion directly impacts the species and suppresses its growth. For instance, the young ones of certain species can take longer to mature in crowded conditions. When there is a high population density, the number of young ones the members of the species can produce decreases. Further, it is often seen that when there is a high population density, many juvenile animals will move away from the regions in which they were born.

This is because they could find territories with more resources and less competition. This dispersal phase can also be detrimental as there is no surety that they will find sufficient resources. They also risk predation as they traverse unfamiliar territories.

It also affects the population size. This is because when there is a high population density, growth is affected, fecundity (the biologic capacity to reproduce) is suppressed and survival is impacted. As such the population starts declining. Once the population has lowered, fecundity starts getting better and survival chances increase. The population then starts growing.

Picture Credit : Google