Most animals are what we would call “cold-blooded” (This is not a proper scientific term, it is more accurate to say they are exothermic and poikilothermic). Unlike humans, they can’t generate their own body temperature and depend on outside heat.
They are also less capable of dealing with higher temperatures, it can cause them to overheat. This means many of the hotter zones in our cities are barriers to their movement.
Our obsession with concrete, steel and glass, the modern designs of our cities don’t take into account the thermal environment. Combined with the tropical heat, our architecture creates an environment that is hostile to life.
Our cities are often too hot for invertebrates, except for hardy pest species. And when there are no other animals to control them, these pests can multiply out of control. But they often are not enough to sustain viable food chains.
Imagine a city where controlling the temperature is a goal, and biodiversity is one of the indicators of whether you can achieve that goal. Living things such as trees, rain gardens, green spaces and green walls can greatly help to dissipate heat.
Not only would it be healthier for all living things, but for humans as well.
Biodiversity is the variety of animals, plants and fungi in an area. It is also the variety of genes within each species.
Many don’t know that Malaysia is country with mega biodiversity, which means that compared to the rest of the world we have many times more diversity. For example in Malaysia we have 6000 species of moths, 2000 species of bees, 8000 species of ants and 200 species of dung beetles.
Of course in cities there are far fewer species. The study of urban biodiversity is about what can survive in our cities and the unique new ecosystems that emerge in them.
An example of urban biodiversity is the patches of pavement plants that grow next to our pathways, or the banyans that take over buildings as soon as they are abandoned. These become the foundation for food chains that allow pollinators or fruit eating birds to live in our cities.
In terms of genetic variety, a good local example is the different breeds of banana that we enjoy. Malaysia has a wide variety of wild and domesticated banana species, and these allow us to have a wide selection of pisang goreng as well as the genetic diversity to breed more resilient crops in the future.
There are practices that we can do to make our cities more friendly to wildlife, this website is a repository of information on how we can create cities that can serve more than just humans.
Sometime in the 19th century, Ernest Haeckel, a naturalist, came up with the word ‘ecology’ to draw attention to something that he thought was important: the ‘entire relations’ of an organism. By this, he meant that it was not enough to study one plant or animal species at a time. He believed it was important to study not only the organism but also its relationships with other living organisms and how it interacts with non-living things like climate, water, soil and light.
This came from the idea that an organism’s home (habitat or surroundings) has a great influence on its form (what a plant or animal looks like) and its behaviour (how it grows, moves, communicates and so on).
Ecology is derived from the Greek ‘oikos’ which means home or household. It is the study of the relationships that exist among living things and between living things and their environment. This includes both non-living things like water, soil, climate and minerals, and other organisms that are of the same or different species.
All plants, animals, fungi and microorganisms form a complex web of relationships—an ecosystem—that supports their survival. Interactions occur at many levels and there are different types of relationships.
A group of the same species living in an area make up a population. Think, for example, of the myna birds you see anywhere near your home: together they make up your neigbourhood’s myna population.
Ecologists can study populations of organisms, examining their behaviours, their adaptations to their habitats, and how their numbers change over time and geographic regions. Some ecologists will spend years studying individuals in a population. They will record their births and deaths, diets, movements, and the impact they have on their surroundings.
Plants or animals also interact with other species in their habitats. A community is a set of several, different species that occupy a given area.
Take a simple house garden. Its trees, flowering shrubs, grass, worms, birds, bees, butterflies, snails, moss and mushrooms form a small community. As a community, they interact with each directly (bees feeding on flower nectar) and indirectly (worms dig through soil and this makes it better for plants to grow later).
Communities can be as small as that of a thinly-populated backyard garden or be found within huge national forests.
Interactions within communities involve processes like pollination, decomposition, and feeding. These benefit the organisms and also provide many services for us. Ecosystem services include:
food and fuel provision
fresh water supply
pest and pathogen control
Ecologists study such relationships and their outcomes, exploring how ecosystems are formed and how they are sustained. Thus, ecology studies contribute to a wide range of fields and practices including agriculture, conservation, natural resource management and sustainabledevelopment.
Here are some of the questions that ecologists try to answer:
How do behaviour and physiology change in response to the physical environment?
How do organisms use the resources in their habitats?
How will ecosystems respond to human activities?
How can we restore degraded ecosystems?
As the world deals with changing environmental conditions, pollution, food security and species loss, ecology helps us understand ecosystems and how to protect them—for our own well-being and that of the planet.
Egerton, F.N. (2013), History of Ecological Sciences, Part 47: Ernst Haeckel’s Ecology. The Bulletin of the Ecological Society of America, 94: 222-244. doi:10.1890/0012-9623-94.3.222
In recent years, ecologists have begun to take a second look at plants and animals appearing in cities. There seems to be more ‘nature’ in urban areas than one would expect. Cities are supposed to be human territories—steel, brick and concrete—not exactly welcoming to wildlife. But urban places display a variety of species and habitats – biodiversity—in places we did not plan for them.
This makes us ask some questions:
Why are these plants and animals surviving in human settlements while others disappear? How and when did they move in? How many of them can survive in our cities?
Urbanized areas often share characteristics like:
hard surfaces (roads, pavement)
roads and buildings that break up natural, vegetated spaces
bright light at night, loud sounds, water and soil pollution
All of these are known to make it difficult for ‘natural’ habitats to survive near cities.
But there are also ‘built’ green spaces like public parks and private gardens that cultivate a wide range of native and exotic plants. These can form the bases of food chains that attract consumers (like ants, grasshoppers, bees, beetle, squirrels) and their predators (lizards, birds, and monkeys), without our approval. If left uninterrupted, patches of wild ecosystems can be established within these built spaces.
But exactly which species of birds, bees and trees settle in cities? Where in a city are you more likely to come across wildlife? And, how come I can see kingfishers in one district but not another?
Another attribute of cities is the diversity of the habitats (or shelters) they can, unintentionally, form. Within one city, you can find
old buildings that create dark and cool shelters
long stretches of roadside vegetation
Each of these will have unique structural features, creating different kinds of habitats.
For instance, reptiles that inhabit open spaces within their original forest habitats will probably adapt well to places in cities that have widely spaced trees and vegetation.
Wildflowers too benefit from the abundant sunlight and absence of competition (bigger plants) in urban patches. These are conditions not found beneath dense, natural forest canopies.
A more familiar example is the ubiquitous city pigeon. Have you ever wondered why this bird in particular flocks in cities worldwide? One reason might be the similarity between its original habitat – rocky cliffs – and the hard, ledged surfaces of city buildings that offer it space for nesting.
There is also another feature of cities that might be important for supporting biodiversity – the greater amount of food available. For species that are not very particular about their diet, gardens, cafeterias, litter, bird feeders, ornamental trees and nutrient-rich waterways offer abundant food resources.
So what does this mean for us?
One reason that ecologists are interested in urban wildlife is the benefits associated with biodiversity.
In natural ecosystems, there is abundant tree and vegetation cover, and processes like pollination, seed dispersal and decomposition that are carried out by large and small animals. All of these contribute services like food production, climate and water supply regulation.
These benefits (also known as ecosystem services) are important for us. If cities can support biodiversity, then they can help in species conservation and contribute these services that keep our environment healthy.
Urban biodiversity still poses many questions for ecologists to explore.
How much green space is enough for biodiversity conservation?
What ecosystem services can we expect from urban biodiversity?
How are urban plants and animals different from those in natural habitats?
How and why do biodiversity patterns vary among cities and geographical regions?
Answering these questions will take time and require that we pay closer attention to the other lives unfolding parallel to ours.
Resources for further reading:
Müller, N., Ignatieva, M., Nilon, C. H., Werner, P., & Zipperer, W. C. (2013). Patterns and trends in urban biodiversity and landscape design. In Urbanization, biodiversity and ecosystem services: Challenges and opportunities (pp. 123-174). Springer, Dordrecht.
Schilthuizen, M. (2019). Darwin comes to town: How the urban jungle drives evolution. Picador.
The term rewilding has been thrown about a lot quite recently but in many cases, the term has been misused to just be about planting trees. Here I explain how ecologists view rewilding, as well as important concepts required to understand rewilding. This is somewhat a summary of a review paper by Perino et al. (2019). If you want to read something more technical you can find the details of that paper in the references below.
Rewilding is not only about introducing wild things to where they can’t be found anymore. To quote Dave Foreman:
“I meant rewilding to instead be about wilderness restoration – restoring wildness with native species and processes. So, let us all remember that rewilding comes from wilderness recovery (or restoration).”
In other words, the goal of rewilding is to restore functions to ecosystems through the reintroduction of native species. This is the main difference between rewilding and ecological restoration, which focuses on the restoration of ecosystem functions without the emphasis on reintroducing native species. This does not mean that ecological restoration is worse; in locations where invasive species are impossible to eliminate or native species cannot be reintroduced, ecological restoration is a more viable option.
What is an ecological function? An example would be a butterfly, which as an adult serves as a pollinator for flowering plants, while, as a caterpillar, it functions as prey for insect-eating birds and a host for parasitoid wasps.
Restoring ecological functions drives 3 processes (simple terms are in bold, scientific terms are in brackets):
Food chains (Trophic complexity)
Disturbance (Stochastic disturbance)
Plants, fungi and animals with a lot of ecological functions create a complex web of interactions. Among these interactions are food chains. This is the process in which energy is stored and moved throughout the ecosystem. The more complex the food chains or food webs, the more stable and resilient the ecosystem will be. This is why rewilding efforts can start with first reintroducing predators back into ecosystems. For example, in Yellowstone National Park in the United States, wolves were reintroduced back into the park first, to regain ecosystem balance. By doing so, you add another level to the food chain and the lower levels of the food chain are regulated by the predators on the upper levels.
We tend to think of disturbance as a bad thing, but that is not always the case in a dynamic system. Random disturbance events help to make ecosystems more diverse and stable by ensuring that no one organism can dominate. For example, in rainforests, large trees will grow and block sunlight from reaching the understory. If the large trees do not die – through falling over, disease, lightning strikes or fire – then there will not be any new space for younger trees to grow. So a forest is not a permanent collection of trees, but it is in a constant state of change in which large trees fall and new trees fill the gaps. This prevents a single tree species from taking over in a rainforest, as many different species fill the niches that become available after a tree fall.
Movement is crucial for maintaining the food chains when disturbance happens. Ecosystems are often patches of resources that animals, fungi and plants can use. Usually, this results in patches with different compositions of species. For example, if there are many species in a single large patch, it can help to rescue populations in other smaller patches through the movement of organisms between patches.
This is why creating networks of patches that enable movement between patches is important. It helps to maintain the food chains in all the connected patches by buffering the random disturbance.
On a large scale, preserving ecological functions pays humans back in the form of ecological services. The previous example of a butterfly supplies the supporting service of pollination. This is necessary for the provisioning services which create food and raw materials for people.
Overall ecological services can be categorised into 3 benefits:
Non-material benefits are things like improvements to human health and wellbeing that can be gained through interactions with nature. Non-material benefits also extend to profits from services such as tourism.
Material benefits are things that you can harvest from nature, such as wood or food. Malaysians have a very close relationship with many species of plants that are used in our culture and cuisine.
Regulating benefits are things that are controlled by having nature around. These include natural disasters like floods and landslides, regulation of heat and climate, and reduction of dust and pollution.
When you have many ecological functions, all these interactions create an ecosystem. Ecosystems, by definition, are living and non-living components interacting in a shared space. The goal of rewilding should always be to restore ecosystems, and that is why we have to be careful about how we use this term and not use it as a buzzword that means only planting trees.
In the next article, I give an example of a successful case of urban rewilding in relation to food chains and interactions, and the lessons we can learn from it, especially from a functional ecology perspective.
Here I explain how you can think about ecosystems and how to restore them. The case study of the Golden Birdwing Butterfly, which can be found in the urban forest patch that is Rimba Ilmu Botanic Garden located inside the University of Malaya. Merely reintroducing a species does not produce long lasting results. Butterfly farms…
Draco gliding lizards are interesting tropical animals. They have ‘wings’ that fold out from their ribs and allow them to glide from tree to tree. They also have a small flap under their chins that acts as both a flag to communicate and like the tail of a plane to stabilise their flight. When I read about them as a kid, they always struck me as incredibly exotic animals that would be really hard to find. It turns out that they are quite well adapted to living in our cities.
There are 11 species of Draco in Peninsular Malaysia. In the natural world, they tend to be found in forest clearings where there is space between trees and not too much dense vegetation. These gaps between trees are usually created by tree fall events. In a mature rainforest, trees fall very often, either due to old age, disease, or unstable soil. Rainforest trees are often connected to other trees by vines or lianas, so when one tree goes down, it can pull down others and crush anything smaller in its path. This is a natural disturbance that creates gaps in the otherwise dense canopies of the rainforest. Young trees and saplings use this opportunity to fill the gap and start the cycle over again.
Many species are known to take advantage of these forest gaps, including gliding lizards. The constant disturbance of tree falls creates more diverse patches of forest, where trees of different species and ages are always going through tree falls and regrowth, nothing staying permanent. This, in turn, creates space for all sorts of gap species that are adapted to these environments. The layperson may view change and disturbance as something undesirable or negative, but these are necessary processes to keep the ecosystem in balance.
In cities, humans are the main force of disturbance. We cut weeds and shrubs and maintain clear gaps between trees. While this may not be good for animals that prefer some shelter, the lack of dense vegetation seems to be a boon for gliding lizards. They can bask in the sunlight created by our sparsely planted trees and glide in between them with ease. Scientists call this pre-adaptation – an organism is predisposed to survive in certain habitat structures, allowing it to take advantage of new habitats with similar features.
A lot of our urban species have, by luck of the draw, found a place for themselves in our urban spaces. So perhaps we should ask the question of how we should use disturbance as a tool for biodiversity and healthier ecosystems, instead of maintaining landscapes just for the sake of maintaining aesthetic practices.
Whitmore, T. C. (1984). Tropical rain forests of the Far East. Oxford University Press, Oxford.
Grismer, L. L. (2008). A revised and updated checklist of the lizards of Peninsular Malaysia. Zootaxa, 1860(1), 28-34.
Here I explain how you can think about ecosystems and how to restore them. The case study of the Golden Birdwing Butterfly, which can be found in the urban forest patch that is Rimba Ilmu Botanic Garden located inside the University of Malaya.
Merely reintroducing a species does not produce long lasting results. Butterfly farms all over the country constantly have to restock wild caught butterflies due to captive butterflies dying and not reproducing. When an animal is placed in a system that does not meet its needs, there’s nothing much that it can do except go extinct.
The secret to the birdwings survival is the fact that it has a functioning ecosystem that produces resources can satisfy its ecological requirements.
In a butterfly farm, the basic requirements for survival are met; the temperatures are suitable and there is enough food supplied through cut flowers and fruit. The ecosystem in a butterfly farm looks like this:
To be more sustainable and reduce the cost of having to feed the birdwings, you could plant food plants for the birdwings, so they can feed on the nectar. Birdwings prefer flowers that grow on in large clusters like Saraca, Ixora and Bauhinia kockiana so they can walk along and feed. The ecosystem would look this this:
As mentioned before, once the end of the lifespan of the butterfly is reached the ecosystem collapses. This is because all butterflies require a host to develop on as a caterpillar, in this case the Birdwings are breeding on a climbing plant known as Pipevine (Aristolochia tagala). If supplied with a host plant, the butterflies can lay their eggs and reproduce and create a new generation. This ecosystem would look like this:
However, Birdwing caterpillars damage the stem once they are about to pupate into a butterfly. This behaviour is believed to increase the nutrient density of the leaves while reducing the water content. Because of that, the above ecosystem will also eventually collapse after enough caterpillars damage and kill off all their hosts.
The special thing about the Rimba Ilmu ecosystem is that it has pollinators for the Pipevine, so the Pipevine can reproduce and replace the population that is lost to caterpillars. What is the pollinator of the pipevine? Tiny flies (Drosophilla spp., Megaselia spp.), which get caught in trap chambers in the flower of the Pipevine and forced to become pollinators without any reward. So a more viable ecosystem looks like this:
Of course since the Pipevine doesn’t feed them for the service of pollination, the fruit flies require their own food source, which is often rotten fruit, decomposing materials or fungus. These decomposition systems happen when there is enough fallen fruit, mulch and rotting logs in the overall ecosystem. This is supplied by leaves, fruit and branches falling off the plants in the system (which is an important reason to always leave some decomposition around). This results in this ecosystem:
The example above is a functioning, self sustaining ecosystem. As long as it gets enough sun it can keep going without any human interference. But the most interesting thing about this ecosystem is the fact that it assembled itself. While this “let nature find a way” approach is possible, we can help it along by being aware of the different parts and the needs of each part of the system. If you want butterflies in your garden, you need to think about more than butterflies.
Naturally occurring wildflower patches are the first step in succession. These small sun loving plants are usually the first to colonise bare land. They then help to regenerate the soil and make it suitable for secondary vegetation like shrubs and small trees to grow.
It should be stated that modern wildflower meadows are not native ecosystems. Many wildflowers found along our roads and in our fields are not native to Malaysia. Some are escaped ornamental plants that have gone wild, others have been brought accidentally by trade and a few have been introduced because of their usefulness to humans.
However, a patch of many small flowers and shrubs are more beneficial to pollinators and wildlife than just a lawn of grass. Stingless bee farms often encourage the growth of wildflowers such as Beggarsticks (Bidens alba, Biden pilosa), Coralvines (Antigonon leptopus), Goat weed (Ageratum conyzoides) and Cupids shaving brushes (Emilia sonchifolia) due to the nectar and pollen that they produce.
Some wildflowers are also food plants adult butterflies and host plants for caterpillars. Passion flowers (Passiflora spp.) are the host plants for the Tawny Coster (Acraea terpescore) and Julia Heliconian (Dryas iulia), while the Touch-me-not plant (Mimosa pudica) is the host for Lesser Grass Blues (Zizina otis lampa) and the Peacock Pansy (Junonia almana).
Some wildflower patches produce fruit and seeds which are eaten by birds. The small sour fruit of the Lavender Sorrel (Oxalis barrelieri) are eaten by Zebra Doves (Geopelia striata) and other small birds. Insects such as grasshoppers, true bugs, crickets, ants and moths that hide in the wildflowers are also the food of insect eating birds. Occasionally smaller water birds will also forage these sites for insects too. Be careful if you intend to use any wildflowers, not all plants are safe to consume or use as medicines. Some wildflowers are harmful to humans and vertebrates, as they can contain poisons that can harm your liver or cause blindness. Be sure to ask an expert before you decide to use any part of a wildflower.