Category Nature Science & Wildlife

WHY ARE RAINFORESTS SO RICH IN LIVING THINGS?

Rainforests are tropical evergreen forests. They have at least 4000mm (156 inches) of rain each year. The climate is warm and moist all year round, giving conditions in which green plants can produce huge amounts of vegetation, flowers and fruit. There is always plenty to eat for insects and the animals that, in turn, feed on them. The rainforest also offers an extraordinarily wide range of habitats for living things.

Rainforests are areas of extremely high biodiversity compared to other ecosystems. In the rainforests of Borneo, scientists have documented more than 15,000 plant species, including 2,500 species of orchids! Biologists estimate that tropical rainforests contain about 50% of the world’s terrestrial plant and animal species, yet they encompass only about 6% of the world’s land area.

Rainforests have 170,000 of the world’s 250,000 known plant species. The United States has 81 species of frogs, while Madagascar, which is smaller than Texas, may have 500 species. An area of rainforest the size of two football fields (one hectare) may have more than 400 species of trees, while an equal area of forest in the United States may have fewer than 20. Europe has 570 butterfly species, while Manu National Park, a single reserve in Peru, has 1,300 species.

Because rainforests are located in tropical regions, they receive a lot of sunlight. The sunlight is converted to energy by plants through the process of photosynthesis. Since there is a lot of sunlight, there is a lot of energy in the rainforest. This energy is stored in plant vegetation, which is eaten by animals. The abundance of energy supports an abundance of plant and animal species.

The canopy structure of the rainforest provides an abundance of places for plants to grow and animals to live. The canopy offers sources of food, shelter, and hiding places, providing for interaction between different species. For example, there are plants in the canopy called bromeliads that store water in their leaves. Frogs and other animals use these pockets of water for hunting and laying their eggs. Many species in the rainforest, especially insects and fungi, have not even been discovered yet by scientists. Every year new species of mammals, birds, frogs, and reptiles are found in rainforests.

Picture Credit : Google

ARE THERE ALSO ANIMALS LIVING UNDER GRASSLANDS?

As grasslands usually have few trees or rocks to offer cover to smaller animals, many of them live in burrows underground. In North America, prairie dogs (Cynomys ludovicianus) live in huge numbers in connected burrows, sometimes causing the ground to cave in. The South American pampas also has many burrowing animals, including viscahas (Lagostomus maximus) and cavies (Cavia aperea), related to guinea pigs. The American bison, coyote, and gopher are just some of the animals that live in the grasslands.

Grasslands cover 25 percent of the world’s surface and it is the preferred habitat for animals like the wildebeest, coyote, and pronghorn. The grasslands provide animals with a variety of diets like grass, shrubs, twigs and even fellow animals for prey. The climate in the grasslands also changes depending on the seasons hence during the dry season, when water and grass are in short supply, animals move to other grasslands.

Swift Fox

Despite the resemblance to a domestic cat regarding size, the fox lives in near harsh conditions of North America especially in Colorado, New Mexico, Kansas, Oklahoma, and Arizona in grasslands. The survival of the fox in the grasslands is based on its omnivore diet of fruits and insects. Thanks to conservation efforts by wildlife authorities, the swift fox was saved from possible extinction. The lifespan ranges from 3-6 years in wild grasslands but in zoo, parks, and other forms of captivity, the swift fox can live for up to 14 years.

Prairie Dog

The structure of the prairie dog is similar to that of a squirrel, but it is their warning call to each other whenever danger lurks that sounds familiar to that of a dog. The grasslands are their preferred dwelling grounds because it provides them with hiding areas so they can protect themselves against harsh weather elements like floods and blizzards during the winter. The grasslands provide grass, seeds, and insects to prairie dogs. Predators do have a hard time trying to hunt the Prairie dog down thanks to the superior anti-predator techniques it has. If a predator is spotted, it employs an alarm response to alert fellow dogs.

Giant Anteater

Also known as the giant ant bear, the giant anteater feeds on ants, insects, and termites depending on the season of the grasslands. It tracks down its prey using scent. The giant anteater can be found in the grasslands of South and Central America. Predators like the puma or jaguar frequently hunt down this animal, but the giant anteater avoids them by galloping away. If cornered, it can use the hind legs, which are equipped with sharp claws to tear apart potential foes in defence. The mobility skills of this animal are remarkable as it can swim across rivers no matter the size. The climate changes cannot affect the animal due to its ability to adapt to cold weather and hot weather.

Gopher

The gopher is a rodent which uses tunnels as a means of protection and gathers food. Like other rodents, it has a small size and claws that are adapted to digging tunnels. Male gophers are slightly larger in size and weight than female gophers. The lifespan of gophers is five years and they can survive despite the threats from known predators like snakes. The gopher lives in the grasslands of Central America and South America.

Badger

Known for producing pelts which are used for making shaving belts, the badger is a sturdy animal that lives in the grasslands in North America. Determining the exact classification of the badger is not easy due to the existence of several species of badgers. However, the badger belongs to the Taxon Mephiditae family. In the past, badgers were hunted for their meat and hide, but due to conservation efforts they are no longer hunted today.

Picture Credit : Google

WHAT DEFENCES DO GRAZING ANIMALS HAVE AGAINST PREDATORS?

For most grazing animals, being part of a herd is their best defence against attack. Although individual animals, especially young, old or sick ones, may be picked off by predators, most animals will be safe. There are also more animals to watch out for danger while the rest graze. When attacked, the best defence of an antelope or zebra is its speed. At least over short distances, it can usually outrun its attackers. Wildebeest and some other heavier animals also have a powerful kick, which can break the bones of a lion or hyena if well aimed.

Defense mechanisms are very important to all animal life. Animals in every biome must eat to survive. With predators being high on the food chain and always on the lookout for a meal, prey must constantly avoid being eaten. Adaptations that prey employ ads to the chances of survival for the species. Some of these adaptations include defense mechanisms that can give prey an advantage against their enemies.

There are several ways animals avoid falling prey to a predator. One way is very direct and comes naturally. Imagine you are a rabbit and you have just noticed a fox preparing to attack. What would be your initial response? Right, you’d run. Animals can use speed as a very effective means of escaping predators. Remember, you can’t eat what you can’t catch!

Another defense mechanism is camouflage or protective coloration. One form, cryptic coloration, allows the animal to blend in with its environment and to mask its identity. Cryptic coloration is important to the survival of many new-born and young animals, as it is often their main defense against being detected by predators. Some animals blend in so well with their environment that it is very difficult to identify them. For example, some insects and other animals can look like leaves; both in their visual appearance and their behavior. It is important to note that predators also use cryptic coloration to avoid detection by unsuspecting prey.

When faced with danger, some animals pretend to be dead. This type of adaption is known as thanatosis. Opossums and snakes can even emit a fluid that produces a foul smell, thus adding to the pretense. Such behavior tricks predators into thinking that the animal is dead. Since most predators avoid dead or rotting animals, this type of defense mechanism is often very effective.

Some animals try to avoid predators by simply running, flying or swimming away as fast as they can. This is a very common defense mechanism that many animals use. Many animals that use speed as a defense live in open habitats, which don’t provide many places to hide from predators. Many animals that rely on speed also have excellent vision or hearing, so they can detect predators before they get very close.

To sum it all up, the predator-prey relationship is important to maintaining balance among different animal species. Adaptations that are beneficial to prey, such as physical defenses, ensure that the species will survive. At the same time, predators must undergo certain adaptive changes to make finding and capturing prey less difficult.

Without predators, certain species of prey would drive other species to extinction through competition. Without prey, there would be no predators. The animal organisms in such an environment could become endangered or even extinct. The predator-prey relationship ensures that the cycle of nutrients in biomes continues. Thus, this relationship is vital to the existence of life as we know it.

Picture Credit : Google

HOW DO GRASSES KEEP GROWING IF THEY ARE CONSTANTLY EATEN?

Grasses are well suited to being grazed. Although many will grow to more than two metres (over six feet) if left undisturbed, they do not need to reach this height to reproduce. Even if a flower and seed head are never allowed to form, the plant can reproduce by sending out runner’s underground, from which new daughter plants can grow. As well as being able to grow upwards from their central stem, grasses also have lower growing points from which new stalks can grow if the central one is cut. In fact, by this means grasses grow more thickly than ever, giving more food for grazing animals to eat.

Grasses are amazing, living beings that most of us don’t really consider of importance. Grasses have evolved with grazing animals so that they can thrive after being eaten by grazing animals. Grasses don’t survive grazing: they thrive with grazing. How do they do it? These reasons are why grasses are particularly awesome, in my book, and how they “survive” with not just grazing, but fire too:

  1. The main growth point is at the very base of the plant, close to the soil surface that doesn’t get eaten by most animals.
  2. Other growth points are at the base of each leaf. A leaf that hasn’t quite reached maturity and is clipped off by a lawn-mower blade or grazing animal will continue to grow. Leaves that have reached maturity die from the tip down. Leaves get continually replaced by tillers at the base.
  3. They have daughter tillers at the base of every parent plant that grow up to replace the senesced or dead parent plants.
  4. Some grass species form ever-growing bunches. Some bunch grasses, like rough fescue, can have hundreds of tillers in one plant. Others spread out via rhizomes forming a dense sod.
  5. Grasses are particularly aggressive and determined to set seed before being defoliated again to spread out as much of their species as possible
  6. Some species are very picky about when to set seed; particular climate conditions and stressors will prompt some plants to set seed, while other conditions encourage them to wait for the right time
  7. Many native grasses are “decreases” under continued grazing (and with no grazing to control them eventually dominate the landscape), while other grasses are quite masochistic and love being grazed (the “increasers”) because it encourages them grow and spread out more.
  8. The roots of grasses are very fibrous and can grow to depths of 10 feet or more; the native prairie grasses of the tall-grass prairie are particularly famous for such massive root systems.

Roots are a good indicator of how healthy grasses are, and not all species have deep roots. Lawn grasses and many forage grasses have shallow root systems. But, root systems become increasingly shallow with continual heavy grazing, unlike those grasses that either doesn’t get grazed at all, or less frequently.

Grasses need predators, though, in order for them to truly thrive and survive. Without predators like wolves, lions, or even humans, grasses can suffer from overgrazing by even the “native” grazers. Predators force grazing animals to move on to fresh grounds, and in doing so allow grasses to rest and recover sufficiently for the next bout of grazing animals to come through.

Grasses can be killed with excessive grazing and trampling. There’s no doubt about that. Simply leave a herd of grazing animals in one small area for a long period of time—and it doesn’t matter what species they are—and you’ll eventually find bare patches of earth showing through. If you remove these animals from that area for a long period of time, those patches disappear and grasses recover to produce a lot of herbage for those animals to consume.

Picture Credit : Google

DO GRASSLANDS ALL OVER THE WORLD HAVE SIMILAR CLIMATES?

The climates of the world’s grasslands vary a great deal. In Africa there are huge areas of grassland called savannah. These are warm all year round with summer rains. They support large populations of seed-eating birds and grazing animals, which in turn provide food for large meat-eating animals, such as lions, leopards, cheetahs, hyenas and jackals. The North American prairies and Russian steppes are similar in having hot summers but very cold winters. Great herds of bison once roamed the North American “sea of grass”, but early settlers killed enormous numbers of them for food and sport. Now the bison is a protected species. South American grasslands, called pampas, and the South African veld have sparser tussocks of grass.

Found in the middle of large land masses or continents. The two major areas are the prairies in North America and the steppe which straddles Europe and Asia. The majority of this biome is found between 40° and 60° north or south of the Equator.

There is a large temperature range between this region’s cold winters and hot summers, as this region is far from the moderating effect of sea breezes (warming in winter, cooling in summer) because they are found inland. A great variety of temperatures may also occur in the same place within a single day. Temperatures may change by as much as 30 °C from day to night, a diurnal (geographer’s word for daily) difference only beaten by hot deserts. However with total rainfall of between 250-500mm per year, this is a much wetter biome than a desert.

Temperate grasslands are known as the Prairies in North America, Pampas in Argentina and in Europe and Asia this kind of ecosystem is called Steppe. In New Zealand this zone includes the Canterbury Plains, and in South Africa it’s part of the Veld.

This biome is of real importance to humans for food production. Their dark, deep soils are amongst the richest in the world. This feature of temperate grasslands means that a lot of this biome is in fact now farm land. For example less than one per cent of the Prairies remain untouched, surrounded by gigantic flat fields of maize and wheat or cattle ranches.

Plants that flourish here are primarily grasses like grama and buffalo grass. It is too dry for trees here. Some grasses grow up to two metres in height in patchy tufts, whereas other feather-like plants carpet a vast area but only grow to a maximum of 50cm. The deep roots of these grasses seek out underground stores of water up to two metres below the ground. In temperate grasslands rainfall is limited apart from in late spring and early summer when seeds wake up and grow quickly, using nutrients released as last year’s plant growth rots down. The new grass provides food for grazing animals like bison, deer, and if you’re in Australia, Kangaroos. The rhea is a big flightless bird that makes its home in South America. They too eat leaves and seeds but also love lizards and beetles. Animals that like meat and veg like Rhea are called omnivores.

Wild animals remain in abundance where temperate grassland has been conserved. In the Prairies grasshoppers feed on grass but themselves make a tasty meal for prairie dogs. Prairie dogs in turn need to keep a look out for predators like rattlesnakes, coyotes and golden eagles. These ground-living squirrels live in colonies or groups and make their homes deep underground. The heaps of soil left by their burrowing form handy look out humps. Underground living can have its advantages in a place where the temperature can vary greatly, from 40 °C in summer (phew) to -40 °C in winter. The temperature also changes a lot within a twenty-four hour period in this kind of ecosystem. In Mongolia temperatures might rise and fall by as much as thirty degrees centigrade!

Picture Credit : Google

HOW CAN GRASSLANDS SUPPORT SO MANY ANIMALS?

When not shaded by larger plants, grasses grow very quickly, especially if frequently nibbled or cut, as anyone who has to help mow a lawn knows. Up to 30% (almost a third) of the Earth’s land is covered by grassland. Grass plants can survive fire, which spreads rapidly across the land but burns for only a short time, as there is little to fuel it. Flash floods are also not a problem, as the shallow, dense roots of the grasses prevent the soil from being washed away.

The global importance of grasslands is indicated by their extent; they comprise some 26% of total land area and 80% of agriculturally productive land. The majority of grasslands are located in tropical developing countries where they are particularly important to the livelihoods of some one billion poor peoples. Grasslands clearly provide the feed base for grazing livestock and thus numerous high-quality foods, but such livestock also provide products such as fertilizer, transport, traction, fibre and leather. In addition, grasslands provide important services and roles including as water catchments, biodiversity reserves, for cultural and recreational needs, and potentially a carbon sink to alleviate greenhouse gas emissions. Inevitably, such functions may conflict with management for production of livestock products. Much of the increasing global demand for meat and milk, particularly from developing countries, will have to be supplied from grassland ecosystems, and this will provide difficult challenges. Increased production of meat and milk generally requires increased intake of metabolizable energy, and thus increased voluntary intake and/or digestibility of diets selected by grazing animals. These will require more widespread and effective application of improved management. Strategies to improve productivity include fertilizer application, grazing management, greater use of crop by-products, legumes and supplements and manipulation of stocking rate and herbage allowance. However, it is often difficult to predict the efficiency and cost-effectiveness of such strategies, particularly in tropical developing country production systems. Evaluation and on-going adjustment of grazing systems require appropriate and reliable assessment criteria, but these are often lacking. A number of emerging technologies may contribute to timely low-cost acquisition of quantitative information to better understand the soil-pasture-animal interactions and animal management in grassland systems. Development of remote imaging of vegetation, global positioning technology, improved diet markers, near IR spectroscopy and modeling provide improved tools for knowledge-based decisions on the productivity constraints of grazing animals. Individual electronic identification of animals offers opportunities for precision management on an individual animal basis for improved productivity. Improved outcomes in the form of livestock products, services and/or other outcomes from grasslands should be possible, but clearly a diversity of solutions are needed for the vast range of environments and social circumstances of global grasslands.

Picture Credit : Google