Acid Rain Effects on Plants & Animals

Acid rain is defined as any amount of precipitation that has some level of toxic metals or chemicals. Even though acid rain can be caused by volcanic gas and debris, acid rain is also caused by the release of sulfur and nitrogen dioxides from fossil fuel production and industrial byproducts. When these particles are released into the air, they can accumulate in humid areas and be incorporated into the precipitation cycle, which continues their negative effects.

Acid precipitation is a growing problem in America and Europe, causing government agencies to instill laws and programs to counteract the negative effects of acid rain. In this post, we’re going over what acid precipitation is and the effects of acid rain on plants and animals.

Acid Rain Definition

The acid rain definition actually includes all forms of precipitation including rain, fog, snow, hail, etc. It’s when any precipitation has acidic properties, aka a pH below 7, as a result of sulfuric or nitrogenous components.

Acid rain can be caused by volcanic eruptions, but recently it has been attributed to the burning of fossil fuels along with industrial byproducts being spewed into the atmosphere.

Reduced pH Level in Water

Acid rain can make the water in lakes and streams more acidic and discharge toxic amounts of aluminum into a water system. Many aquatic animals cannot thrive in a low pH environment; acid rain has many negative effects on plants and animals in the environment.

The death of aquatic animals results in other animals within the habitat to have a lack of food, thus throwing the entire food web and ecosystem out of balance.

Damage to Forests, Plants, and the Food Web

Acid rain damages the leaves of trees and plants, thus limiting their growth and exposing them to the metals in the air from the toxic rain. Depending on the severity of the damage, the vegetation can be stunted in its growth or the foliage can be stripped away.

The damage can also destroy a plant’s ability to handle cold or disease, which can also negatively impact the food web.

Poisoning of the Soil

When acid rain absorbs into the ground, the soil becomes more acidic, which dissolves helpful minerals in the soil. Acid rain also releases toxic substances, such as aluminum, into the soil and has poisonous effects. The effect of acid rain on plants and animals can be mitigated under certain conditions, such as having a thick layer of soil and having certain types of bedrock under the soil to absorb the rain.

Effects of Acid Rain on Plants and Animals

When fish are exposed to acid rain, the disturbed levels of minerals in fish will affect their reproductive system and the females will not release eggs. When certain fish are in water with a very acidic pH level, the mucus on their gills will become very sticky and will eventually stick together, causing them to be unable to receive oxygen from the water.

Case Study on Acid Precipitation

A study was done in the Netherlands about the exact effects of acid rain on a given habitat. They noticed that acid rain leached calcium from the soil, which was the primary source of calcium for snails in that environment.

Result of bad ecology. Compare this two leafs. One of this after the acid rain …

The snails soon died off, which was the primary source of calcium for birds in that habitat. The birds had to look to other sources for their calcium, such as insects. The birds were not able to receive a significant amount of calcium and began to lay defective eggs.

Facts About White Oak Trees

The white oak tree (Quercus alba) is a long-lived tree used for shade in landscapes and it is one of the most important timber species in the United States. The “National Audubon Society Field Guide to Trees” reports that the white oak has the nickname stave oak, since its wood is integral in making barrels. Shipbuilders in colonial times valued the wood as well.

Today, white oak goes into products such as flooring, furniture and beams. The white oak’s range includes most of the eastern United States. The tree is vital to the animals that exist where it grows.

Size, and Form and Growth

While some of the biggest white oaks measure as tall as 150 feet, the average tree of this species grows between 80 and 100 feet high. The trunk’s diameter can exceed 4 feet and the tree takes on a broad round look when mature. On some individual white oak trees, the lower branches become gnarled and grow horizontal to the ground. While they aren’t commonly found in nurseries due to their slow rate of growth, white oaks are prized landscaped specimens for the shape of their wide-spreading branches.

The slow-growing trees are also long-lived with specimens surviving for hundreds of years. The white oak is difficult to transplant successfully due to its slow growth, making a full-grown oak even more valuable.

Identifying Characteristics of Quercus alba

white oak leaves.

The leaves of the white oak are about 5 inches long and 3 inches wide, with from seven to nine round-ended lobes on each leaf. The upper sides are a blue-green color, with the underneath surface a whitish shade of green. The white oak’s wood when first cut is light beige to almost white, an aspect of the tree that gives it its name. The grayish bark features grooves and rectangular scales, with deep grooves appearing at the bottom portion of the trunk on older white oaks.

Quercus alba produces both male and female flowers. The pendulous clusters of yellow-green male flowers appear first and are followed by the spiky, reddish female flowers. In autumn, the leaves turn a reddish color, ranging from brownish red reddish purple.

Fruit of the White Oak Tree


The acorns produced by the white oak are a major source of food in the tree’s ecosystem. These fruits are about 3/4 inch long, egg-shaped with a shallow cap and need but one season to grow to maturity. A wide array of birds including turkeys, pheasants, grackles, woodpeckers, jays, thrushes and nuthatches depend on them in the fall for nutrition.

In addition, mammals as large as the black bear and the deer and as small as rabbits, voles and mice include the acorns in their diets. Populations of some species fluctuate in proportion to the amount of white oak acorns available each year.

Insect Threats

gypsy moth

A variety of insects will launch attacks on a white oak, among them the larvae of the gypsy moth and other moths. The caterpillars, when present in large numbers, may defoliate sections of the tree. Other bug pests like the oakleaf caterpillar and orange-striped oakworm can devour foliage.

Economically, the most significant insect that bothers white oak are the wood borers, which can cause defects in the lumber of still-standing trees. Scales are a group of insect pests that feed on sap and cause fungus to grow on the trees. A common white oak tree adaption to insects feeding and laying eggs is the development of galls. Galls are areas of irregular tissue growth that can become harmful to the tree over time.

White Oak Facts

The white oak tree ranges from southern Canada to Florida and as far west as Minnesota. It is the Illinois state tree, as well as the state tree of Maryland and Connecticut. It’s called white oak because newly-cut wood appears light in color and is nearly white.

While not considered an edible species, historical evidence suggests that native Americans consumed white oak acorns after boiling them.

Five Types of Ecological Relationships

Ecological relationships describe the interactions between and among organisms within their environment. These interactions may have positive, negative or neutral effects on either species’ ability to survive and reproduce, or “fitness.”

By classifying these effects, ecologists have derived five major types of species interactions: predation, competition, mutualism, commensalism and amensalism.

Predation: One Wins, One Loses

Predation includes any interaction between two species in which one species benefits by obtaining resources from and to the detriment of the other. While it’s most often associated with the classic predator-prey interaction, in which one species kills and consumes another, not all predation interactions result in the death of one organism.

In the case of herbivory, a herbivore often consumes only part of the plant. While this action may result in injury to the plant, it may also result in seed dispersal. Many ecologists include parasitic interactions in discussions of predation. In such relationships, the parasite causes harm to the host over time, possibly even death. As an example, parasitic tapeworms attach themselves to the intestinal lining of dogs, humans and other mammals, consuming partially digested food and depriving the host of nutrients, thus lowering the host’s fitness.

Competition: The Double Negative

Competition exists when multiple organisms vie for the same, limiting resource. Because the use of a limited resource by one species decreases availability to the other, competition lowers the fitness of both. Competition can be inter specific, between different species, or intraspecific, between individuals of the same species.

In the 1930s, Russian ecologist Georgy Gause proposed that two species competing for the same limiting resource cannot coexist in the same place at the same time. As a consequence, one species may be driven to extinction, or evolution reduces the competition.

Mutualism: Everyone Wins

Mutualism describes an interaction that benefits both species. A well-known example exists in the mutualistic relationship between alga and fungus that form lichens.

The photosynthesizing alga supplies the fungus with nutrients, and gains protection in return. The relationship also allows lichen to colonize habitats inhospitable to either organism alone. In rare case, mutualistic partners cheat. Some bees and birds receive food rewards without providing pollination services in exchange. These “nectar robbers” chew a hole at the base of the flower and miss contact with the reproductive structures.

Commensalism: A Positive/Zero Interaction

An interaction where one species benefits and the other remains unaffected is known as commensalism. As an example, cattle egrets and brown-headed cowbirds forage in close association with cattle and horses, feeding on insects flushed by the movement of the livestock. The birds benefit from this relationship, but the livestock generally do not.

Often it’s difficult to tease apart commensalism and mutualism. For example, if the egret or cowbird feeds on ticks or other pests off of the animal’s back, the relationship is more aptly described as mutualistic.

Amensalism: A Negative/Zero Interaction

Amensalism describes an interaction in which the presence of one species has a negative effect on another, but the first species is unaffected.

For example, a herd of elephants walking across a landscape may crush fragile plants. Amensalistic interactions commonly result when one species produces a chemical compound that is harmful to another species. The chemical juglone produced in the roots of black walnut inhibit the growth of other trees and shrubs, but has no effect on the walnut tree.

How Long Does Each Stage of Ecological Succession Take?

Each stage of ecological succession can take 100s to 1,000s of years – if not more. That is true, but only in a forensic sense. The assumption of ecological succession is that it is a forward moving, and linear path. As more of humankind encroaches on the natural world, the linear progression of this methodology is changing itself. That someone seems fitting for a theory that talks about the inevitability of change.

How is Mankind Changing Ecological Succession?

To best illustrate this, let us return to our first example – the rock face. Let us suppose that the granite wall was quarried by man, and then abandoned once they had what they needed. This allows for a primary stage to begin. Left alone by man, it could quickly pass into a secondary stage within a hundred years or so.

Another few centuries after that, the old quarry is slowly entering its stable climax stage – except – now man has returned to build a road. One thing that ecological succession recognizes is the death of an ecosystem. That is what occurs when a climax stage ecosystem like the rain forest is destroyed by logging. Yet when a climax stage ecosystem is only interrupted, it is not yet understood whether it returns to the secondary stage, or would still be considered at its climax of ecological succession.

Stages of Ecological Succession

Succession is a scientific term describing the long-term progression of biological communities that occurs in a given area. Ecological succession breaks down into three fundamental phases: primary and secondary succession, and a climax state. The study of ecological succession generally focuses on the plants present on a particular site. But animal populations also shift over time in response to the changing habitat.

Ecological succession is the term used to describe what happens to an ecological community over time. It refers to more or less predictable and orderly set of changes that happen in the composition or structure of ecological community. When you are born, your learn to crawl, then walk and then run. When you grow old, your body goes through certain predictable changes over a period of time as in your body grows taller, your hair grows longer, your mind and body develops. Similarly, when you plant a tree, it grows slowly and then grows bigger and bigger and bigger. Basically, its a predictable set of changes that are visible over a period of time. The time scale can be decades or even millions of years.

It is different from Ecological Evolution because the changes that occur aren’t evolutionary in nature, but they may be adaptive. It is based on the principle and knowledge that nothing in life ever remains the same, but that all habitats are in a process of constant change as a result of the inter-dependencies and reactions within the ecological system itself.

Primary Succession

Primary succession occurs when organisms colonize an area devoid of life, usually after a catastrophic natural event that leaves the land barren. Often the first organisms to take hold are algae, fungi and simple plants such as lichens and mosses.

Over time a thin layer of soil builds up so that more advanced plants, such as grasses and ferns, can take root. Along with the successful colonization of plants come animals such as insects, birds and small invertebrates. One example of primary succession is the pioneer communities that begin to inhabit a newly created lava bed, where life cannot exist until the rock surface cools to a moderate temperature.

Secondary Succession

Most ecological change occurs as secondary succession. In fact, most biological communities are in a continual state of secondary succession. This term describes the process in which an established community is replaced by a different set of plants and animals.

Secondary succession is gradual, always moving toward the climax community. Most ecosystems, however, experience disturbances — either natural events such as wildfires or flooding, or man-caused events such as logging — that set back the progress of succession.

Intermediate Stages

An ecosystem undergoes many intermediate stages of succession. These changes form a continuum between the two endpoints, with the actual stages being merely a fixed glance at the never-ending progression of plants and animals.

The emergence of the climax state of succession may occur more quickly in some ecosystems, and likely never occur in other biomes that experience routine disturbances. Examples of quickly forming climax communities are the short-grass and long-grass prairies of the Great Plains of the United States.

Climax Communities

Climax communities are relatively stable and can vary widely in a given region, especially when the landscape consists of high mountains and low valleys. In such cases, the final biological matrix of plants and animals can cover vast tracts of land or be limited to a very small pocket within the landscape. Overall, a climax community is very dependent on rainfall, soil, altitude and temperature. California, for instance, includes many different and distinct ecosystems. One of the most unique places is the redwood forest, which can be found only in the fog banks along the coastal waterways of the northern part of the state.

The path and endpoint of succession

The early ecologists who first studied succession thought of it as a predictable process in which a community always went through the same series of stages. They also thought that the end result of succession was a stable, unchanging final state called a climax community, largely determined by an area’s climate.

For instance, in the example above, the mature oak and hickory forest would be the climax community.Today, the idea of a set path for succession and a stable climax community have been called into question. Rather than taking a predetermined path, it appears that succession can follow different routes depending on the specifics of the situation. Also, although stable climax communities can form in some cases, this may be uncommon in many environments.

Ecosystems may experience frequent disturbances that prevent a community from reaching an equilibrium state or knock it quickly out of this state if it manages to get there.

Importance of Ecological Succession

Ecological succession is of great importance as:

  • It provides information, which help to have control on the growth rate of one or more species in a given geographical area.
  • It helps in reforestation and forest management programmes.