The great flood of 2010 was not only an eye opener for those affected but also a matter of grave concern for biodiversity experts and environmentalists. A random footage of the flood affected areas showed briefly a varanus flicking its tongue in total confusion. Either it was tired of endless swimming or unable to find a tree or land for relaxation and warming up its body. Similarly, the flood must have uprooted foxes, jackals and various species of snakes.

A flood victim from the southern Punjab area had seen different kinds of snakes in the flood water, forced by the current, trying to catch any branch of a tree that could be grasped while many hung on recumbent branches particularly those of mango trees that usually have low branches.

There was also considerable damage to wild flora, firewood stacked in markets for sale and trunks of various pines stored for furniture-making. Estimates suggest a loss of around two fully grown million trees. The loss of dried grasses and date branches for thatched roofs could be around five million and bushes and grass on an area of one million hectares was completely destroyed. For rehabilitation people will need as much wood and grass again to make their houses and then some for firewood. Villagers stock up on that they need for cooking and agricultural purposes.

Many species of endemic bushes and grasses, some endangered and threatened may also have been lost completely with no hope of reviving them in their former habitats as there is no record of their existence nor are their seeds available anywhere, explained Dr Suraiya Khatoon of the Botany department of the University of Karachi at a seminar on threatened bushes around Karachi. This creates additional pressure on trees growing in areas not affected by the flood which means further depletion of the existing wood mass, grasses and fertile soil. The reduction of green cover means less rainfall and a rise in temperature, which combined with global warming will melt more glaciers and result in more floods.

The seeds and spores of various trees, bushes and grasses formed a part of the diet of hundreds of species of birds. Normally, they feed the young during their developing stages to balance their food intake which reinforces their immunity and health to provide them antibodies and stamina for survival throughout their life span.

The food chain is complex but it ensures the survival and the continuation of species from time immemorial. Since different species of mammals, birds, insects, invertebrates, reptile, amphibians, insects, bacteria are specific to their biotopes, their survival depends on the availability of food locally. The relation between flora and fauna is intricately interwoven and any disruption means damage to the species.

Since the floods have damaged the food chain, the loss is in the same proportion as the loss of habitat. There will be variations in the species of flora and fauna, depending on the type of habitat that emerges after the worst is long behind us.

For example the eggs, larvae and cocoons of butterflies and insects were swept away by the flood.

Their revival depends on the introduction of the same species only if the flora on which they survived and bred also grows back in the area with the same intensity as before. Their eggs must arrive with the wind or normal rainfall from where they are still present. If these conditions are not met the entire tract will be without butterflies and insects and the required flora.

The planet earth is not colourful by chance; it follows a certain natural order and the conditions to let nature flourish as programmed. Our mountains and valleys are full of very pretty wild flowers, and herbs of medicinal value. The gushing flood waters swept those away because they were embedded in the top soil. Consequently, these areas may be less colourful in the blooming season and the herbal wealth reduced alarmingly.

The regeneration of the same species of flora or fauna will only occur when the climate, micronutrients, nutrients and other requirements for reproduction are optimum in the wild. There may be different species present depending upon what the flood has brought, provided they have survived after the water dries up and can grow in the changed habitat.

Since birds consume wild seeds, shoots and insects, some species learn to eat what is available or perish with time because of malnutrition as the food now available may not meet their natural demands.

The top soil contains the fertility ingredients in the shape of aerobic, anaerobic and the nitrogen-fixing bacteria which are found usually between one and half to two feet from the ground surface. Floods usually destroy the top layer of soil, leaving it bereft of essential growth factors, that will affect the sustenance of rabbits, and dozens of species of the wild rodents.

Hence birds of prey like owls, eagles and small mammals like jackals, foxes, jungle cats and mongeese lose most of their staple food which consists of rats and rabbits. Larger mammals like the hog, deer and desert gazelles are in a tight corner, along with cattle that provided livelihood to millions.

Floods also wash away invertebrates like earthworms which are biological bulldozers and burrowing mammals that bring the inner soil on the top making the area porous. The chances of soil becoming infertile are higher because flood waters bring silt, pesticides, industrial waste, insecticides, and dangerous factory affluent. It is a hit and miss situation, but hopefully good for wild flora, agriculture, insects and crops that can grow in flood affected areas.

The flood has also swept away another lifeline that the flora require to stay healthy and productive. Nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, iron, maganese, copper, zinc, boron, molybdenum, plus a number of other elements like chlorine, nickel, sodium and silicon are important for growing a good crop as well as wild and farm fruit.

The role of trees in restricting the flood water is immense: you hold a fistful of soil in your fist, put your fist under a running tap. Only ten to thirty percent of the soil would be washed away; ninety to seventy percent of the soil, rich in fertility will be retained. Silt deposits in the delta restrict the flow of the flood and thus divert the course of the river, which spills over its embankments and drowns more people and agriculture.