Role of Turtles in Food Webs & Ecology

Ecosystems are defined as the environment in which certain living and non-living components are incorporated. Here the livings and non-living organisms interact with each other and also the former with other living organisms. The interactions between living organisms are of different kinds that are defined and divided into different kinds by scientists. One of those interactions is Predator-Prey relationship. Like all other living beings turtles also make interactions and play important roles in different food chains and webs. Many reptiles including turtles are herbivores and carnivores.

Turtles and tortoises eat plants, herbs, fruit and other things that categorize them as vegetarians.  Some are omnivores like Slider turtle and American painted turtles. In these webs and food chains they prey over many and being preyed by many as well. Human beings are not away from any of their predator, if we see their food pyramid.

Turtles play important roles in food chains and in the cycles of life within their environment. They are able to convert poor quality feed material to a useful form of nutrients, even that poor quality feed which is not suitable for livestock or any other domestic or non-domestic animals. They prey over small rodents and small crustaceans thus preventing the harmful effects produced by them after being engulfed by large animals and this also helps in breaking the life-cycle of many parasites from Fasciolidae family, Trematods and Nematodes.

Turtles play important role in carrying energy. They gather energy while eating from the pelagic zone and from the aquatic environs and weight till the breeding season that is in most case in November or round about winter. For nesting they always come to seashore where they lay eggs. In these eggs they bring energy of the sea to land. These eggs provide food to their predators in the time before hatching. In this way they make good energy relation between sea and land. The hatchlings move towards sea again after being able to crawl. And they carry rest of the energy to the sea again. Thus turtles not only bring gift of new generation with them to land but also energy for their next generation and predators on land.

Man in one way or the other has used dead turtles in the past. Man has been benefiting himself from the remnants of dead turtles. He has made purses, waist-belts, therapeutics powders, decoration pieces and so many other pleasure articles using turtles’ skins, shell, offal, nails or claws etc.

Regarding to what turtles eat is that they happened to be omnivores. They eat flesh, vegetables, grasses, small insects, and larvae of many animals. For example the Red-Eared Slider turtle, which is thought to be a newly emerged species among Slider Turtles, eats different types of things or preys at different phases of his life. For example he is more like a carnivore when young eating insects, worms, tadpoles, small fishes and surprisingly Carrion (Dead, filthy fishes). Turning to adult stage of life they start also with the vegetarian diet, but do not let flesh go. Being Carnivores, turtles have several interesting and versatile ways to catch up their prey. Mostly the aquatic turtles draw their prey into the mouth while sucking in water. This helps them to engulf the prey easily and not allowing it to escape out, while the jaws are closed (or lips as turtles don’t have teeth). Not only the voracious eating habits are worthy in the wild war of predator and prey but also some life-styles with body sizes and shapes are important. If slider turtle preys over so many animals and lives then similarly he undergoes the experience of being preyed. But the safety measures like the large body size, shell hardness, bite size may be running (swimming) ability to most extent does save them and protect from predators, however crocodiles and alligators are exceptions.
Although grazing by herbivore turtles have profound effect on the vascular and non-vascular plants in the environment but not like the omnivore tribe who not only affect plants but also the flesh and blood species, small sized and medium sized including snails, small fishes etc. Since omnivorous behavior is of this much significance so now a days it is being worked on by many scientists in many regions for the importance of turtles in national and international economy plus human benefits.

Talking about another turtle named Snapping turtle is an Omnivore; like all other omnivores it eats both plants and animals. While eating and being eaten by many living beings around it in its ecological niche, it plays important ecological roles. It cleans up all the dead organisms and their parts by eating them, as described above they even eat carrions, and scavenge the microbes also from aquatic environment. It is endangered by the hands of skunks, fox, raccoon and minks at the Non-hatch stage while large fish, hawks, crows and herons, eats up small snapping turtles. And last but not the least the hugest scavenger, is the Human Being who eats the adult form of turtles not only by teeth but also by his machinery and industry.

By now I’ve been discussing turtles’ diet and food webs in quite civilized green lands, aquariums, ecosystems of lakes and oceans but there is still very interesting and surprising food web remaining; that is of the Desert. Desert Tortoises are important part of life in deserts. We find small, young, huge, dark, dry crawling tortoises in deserts. Many television channels have documented them but still much work is going on for their survival and conservation. They are hardy individuals who can bear harshness of nature. They move around in search of food and during their travel they are at risk of being preyed by scavengers who are in their search as well. Desert tortoises are nomadic in habitats but are possessive for their territory. They show extremely voracious attitude towards any new comers to their area. They are particularly harsh towards tortoises. They make burrows and live in them in the daytime and during the night times. Some tortoises share the burrows with ground turtles so they don’t dig their own. While some don’t even need any home as they migrate towards summer or winter ranges.

This was a brief introduction about the way of life and habitat that can tell about the kind of edibles and the predators of desert tortoises. They like to have different kinds of grasses; protein rich food is preferred in the form of wild flowers, wild grasses. Definitely they need water and moisture that is attained by the only source in the form of dewdrops and water in the plant leaves and stems. Desert tortoises retain this water in their urinary bladder. Dehydration occurs if this water is lost from their bladder.

Interesting to know that dehydration occurs only after urination and they urinate only in order to offend their invader tortoises to show their possessiveness towards their territory. Herbivore varieties of turtles have also a great impact on their ecosystems. Regarding the sea turtles that eat grasses in the sea and aquatic ecosystems play important role in regulating the nutrient cycle in their surroundings, among their colleagues and related predators and preys. Sea grass is the most darling food of sea turtles with an herbivorous nature. But they grasp only large parts of the grass and plants leaving smaller leaflets and young stems, which are richer in nutrient quality. This richer part of grass is eaten by other species with sharper teeth and jaws. Thus turtles go for easy grapping of food with slower mastication in their mouth having a larger bolus in their buckle cavity helping other faster species to get more nutrients in addition to the satisfaction of faster chewing habits of latter. These portions of small and larger grasses are attributed to sea grass-turtles. The availability of small leaves depends on different factors like population of herbivore turtles and other herbivores. In return the frequency of sea turtles depends upon the season, location, climate, predators, hunters and frequency of visitors to that place.
All these factors influence the balance of energy and nutrients in the ecosystem whether it is within the vicinity of aquatic ecosystem or it is a trade of energy by the turtles with the land as described above. Researches carried out on the effect of herbivore by the turtles in the aquatic ecosystems considering parameters like productivity, growth rate, nutritional value, availability and effect on the population of turtles and their predators.

We are talking about the predators of turtles that are a threat to turtle populations. No doubt larger animals like alligators and crocodiles are most common predators for adult turtles while small baby turtles are at stake due to so many animals in their surroundings. But one type of threat to the life of turtles that may lead to their death or may cause weakness and illness to turtles; these are parasites. Parasites who are both internal and external like all other living beings. In addition to parasites other multiple factors that lead to the decline of turtle and tortoises population are environment, pollution, famines, unhygienic conditions, invaders or introduction of new genes and diseases into their area, captivity, stagnant pond waters, low immunity in captive turtles, lack of original environment, poor diet and feed quality, lack of their light requirements i.e. UV-light, cracks in their shells, fungus etc.

During all the study I’ve found that turtles are most endangered by the Human Beings instead of animals. They use it for trading, industries, eating, clothing, jewelry, pleasures, hunting, particularly the steeling of their eggs from turtle farms makes their conservations difficult and problematic. The effect of human invasion has been found not only on the population of turtles but also on that of their predators in the areas of human penetration. The whole scenario in the turtle ecosystems tells the stories of human effects including their fauna and flora. People taking beaches, as good sites for business and resorts building have been hard on turtles and other aquatic species. Developments in fishing techniques are found to be the reason for many turtle species to be extirpated. Big nets, boat strikes, pollution from industry wastes are all the hazards caused by human beings to turtles. With all increasing advancements there is a decreasing trend in ignorance regarding this particular species. Although fishes are being painstaking in some respects by authorities because they are of human interest in all races of man unlike turtles that are only of the interest of a certain business class. But that class should not only utilize them for their benefit but also try to keep that specie in pace with all the new technologies and advancements.

Though in our area particularly in Pakistan such type of interest in turtle business has not been developed by now since it is not much of a kind of area required by the turtles and their breeders. Turtles can live in all types of environments. Their business and farming should be practiced for the conservation and betterment of this specie. They are much useful for their skin and offal other than being used as food.

No matter how harsh nature has been in the form of predators but there is always a balance between species of predators and preys, if nature vanishes it replaces with a better one. If a predator kills one member of specie two new comers restore it. This is the rule and pattern of nature. In nature there’s nothing for us human beings to worry about for the conservation of animals and endangered species. But where our role comes is the point when we interfere in the rules and cycles of nature. When human beings imperil any specie of animals or plants as the case may be, it is the duty of mankind to conserve that too.

Turtles play important roles in their cycles and ecosystems where they not only influence their predators, related fauna and flora but also human beings in one-way or the other. We need to acknowledge the importance of live turtles instead of dead turtles. Not only for the sake of turtles but also for the benefit of nature, conservation of balance in the ecosystems and for keeping the whole food webs alive in which they play important role or only a skimpy role.


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"Remember Me When You Raise Your Hand For Dua"
Raheel Ahmed Khan
System Engineer
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