Categories
ecosystem Environment

What does a pond do?

A small container pond full of Azolla plants

What comes to your mind when you hear of a pond?

The word ‘pond’ refers to a body of water that is usually shallow (no more than 2m deep) and smaller than a lake. Unlike a stream or a river, a pond is enclosed. Therefore, pond water is always stagnant. Natural ponds are filled by rainwater or underground springs and there are also man-made ponds.

Despite its small size, a pond plays an important role in maintaining ecosystem functions and supporting the biodiversity of an area. A pond is home to aquatic animals like shrimps and fishes, and smaller wildlife like beetles, water striders, and snails. It also attracts water-loving creatures such as dragonflies, damselflies, frogs and toads. These animals lay their eggs in the pond, where their young hatch and mature.

Many pond animals feed on debris or fresh organic materials like leaves of plants. Some predatory pond wildlife prey on other smaller animals such as tadpoles and insect larvae. Terrestrial animals like birds will also visit a pond for drinking or bathing.

A dragonfly preys on other insects such as mosquitoes. Photo by Siti Syuhada

Aside from animals, there are various plants that grow in and around a pond. These plants are good for the pond. For example, the mosquito ferns (Azolla sp.) and the Mexican sword plant (Echinodorus palifolius). They absorb nutrients from pond water or sediment. In turn, these water plants supply oxygen to the pond, inhibit algae growth, purify pond water and provide food, shade and hiding places for wildlife.

There are also many other pond plants, categorised according to their growing zone. Plants that grow at the edge of pond are known as marginal plants. The floating plants, for example, duckweed, have tiny roots that absorb nutrients directly from water. Some deep water plants such as water lilies have leaves on the water surface and roots that are buried in the mud at the bottom of the pond. There are also submerged plants that are completely under water, like the Indian swamp weed (Hygrophila polysperma), but they do need some exposed surfaces of pond to receive sunlight and carry out photosynthesis.

Floating leaves and flower of water lily. Photo by Goh Shang Ming

There is so much going on in ponds. The next time you find a pond, take a closer look to see all the life it can hold.

Categories
Environment

The average urban animal

We tend to view our species as average, that cannot be further from the truth

As humans we view ourselves as nothing special. This thinking causes all sorts of problems for the wildlife around us, because humans are in fact quite extraordinary creatures, and when we design our spaces for extraordinary creatures we exclude the average animal.

If I was to describe the average animal species, it would be cold-blooded, it has a narrow diet, it is very small in size, likely it can fly and it would be negatively affected by artificial light.

Humans are fantastic at sweating and warming ourselves up. We have one of the best heat regulation systems in the natural world, and it is so good that we rarely think about it. 

We can heat ourselves up when we are cold and sweat off any excess temperature. Many animals have to depend on their environment to be able to do so.

The average urban animal is closer to a small insect than a human.

But this leads us to build cities that are designed for amounts of heat that humans can handle, but many other animals cannot. We also carelessly use materials like concrete and glass that reflect a lot of heat, creating areas that are bearably hot for humans but lethal to some animals.

We eat a lot of things. Our diets are very wide, and we take food from many different levels of the food chain. Compare that to the limitations that most animals face: predators usually have a small set of prey that they can hunt or some herbivores are limited to only single host plant.

When designing habitat, we should consider that many animals have a limited set of items that they can feed on. Many butterflies need host plants to survive, and without these plants you can’t have enough caterpillars to sustain a population of insect feeding birds. 

Many birds are limited by the design of their beak, if there isn’t the right types of fruit or seed available they might not be able to survive in an environment.


We are very much in the upper limits of animal size. We usually compare ourselves to megafauna we see on National Geographic, but considering that the smallest animals are smaller than specks of dust and most animals are actually less than a few centimeters in length, we’re really big. And this is a problem when we think about habitats, we assume that animals need as much space as us. In many cases they can do with less. 

Frogs can live in a system that consists of a few ponds or streams, millipedes can spend their entire lives in a single log and populations of butterflies can survive in small parks or patches of forest. 

Most animals are capable of flight.

The modern human lives in a 2-dimensional world, we rarely need to move upwards or downwards unless we are changing the level that we are on. Therefore we rarely think about 3-dimensional space, especially space that can be reached through flight.

Most species of animals can fly. Most insects are able to fly at least at one point of their lives, birds are capable of flight, mammalian bats can fly, even reptiles and amphibians have evolved the ability to glide. 

This means that they can move in ways that humans can’t. Roads with heavy traffic may be an obstacle to humans, but not a bird. The ledges of buildings and the rooftops of our cities are all fair game for animal habitat. 

We can create light and it doesn’t have a seriously negative effect on us. This is not the case for many animals with strict activity periods. 

Artificial light can extend the activity of birds, causing them to use up more energy or become more stressed. It can be downright lethal to many insects since it affects their navigation and causes them to fly about lights until the die of exhaustion or get eaten by predators.

Humans are a special class of our own. And when we consider the needs of animals we need to consider that animals are very different from us, so we need to design with their need in mind as well. When we do that, there is a surprising amount of space for us and our animal neighbours.