RECENT DEVELOPMENTS IN ECOLOGICAL ISSUES AND BIODIVERSITY CONSERVATION
NREM 903: RECENT DEVELOPMENTS IN ECOLOGICAL ISSUES AND BIODIVERSITY CONSERVATION
Dr Gentle Wilson Komi
Outline
Introduction
Species diversity
Genetic Diversity
Ecosystem Diversity
Introduction
No one knows the total number of species on earth. About 1.4 million species have been described but it is estimated that there may be more than 5 million.
Science states that it has taken 3.5 billion years for the evolving of this biodiversity. Le cointre and Guyader (2001); Cracraft (2002) put described species as between 1.5 and 1.75 million.
Reyamand Dasmann in 1968 was the first to use the term biological diversity. This later evolved to biodiversity through W.G. Rosen n 1985 and was first used in a publication by E. O. Wilson in 1988.
Wikipedia defined biodiversity as the degree of variation of forms within a given species, ecosystem, biome or an entire planet. It is a measure of the health of ecosystems.
It is in parts a function of climate. For biologists the definition is seen as a totality of genes, species and ecosystems of a region.
The United Nation Earth Summit of 1992 defined it as the variability among living organism from all sources, including terrestrial, marine, other aquatic ecosystems and the ecological complexes of which they are part: this includes diversity within species, between and of ecosystems.
Biodiversity can also be defined from the molecular and genetic levels. Three attributes make up biodiversity i.e composition in the amount of different living things in an area and the volume.
Structure in the elements and the landscape: it involves the shape and spatial arrangement of the vegetation. Function in the interaction of the living things with each other breeding, feeding etc.
Biodiversity increases as you move towards the equator. This might be due to more, sunlight and rainfall. All these result in more primary producers and thus an enlarged food chain/web.
Species diversity: Species diversity can be explained as the number of different species in a particular area weighted by some measure of abundance like biomass. It is made up of two parts:
a. Species richness (S) which is the number of species in an area in a simple count.
b. Species evenness (E) this quantifies how equal the abundance of the species are. It is also the relative abundance with which each species is represented in an area.
Ecosystem diversity: It can be said to be the variety of ecosystems in the biosphere, the variety of species and ecological processes that take place in different physical systems.
Ecosystem diversity is associated with the distribution of species, patterns of communities, roles and functions of major species. It combines the functions and interactions of species.
Genetic Diversity: This is the diversity at the level of genes. The differences in terms of the allele’s i.e different variants of same gene e.g. brown or blue eyes, genes and chromosomes.
It can be measured at different levels like species, population, community and biome.
The more the genetic diversity in a species or population it means better capability of some of the individuals to adapt to changes in the environment.
THREATS TO BIODIVERSITY
1. Global climate change: The earth is said to be warmer now than it was some 40 mill, years ago.
Changes in climate are occurring at a rate that is faster than organisms can adjust to.
It can cause a shift in the distribution of species. There is a movement of species towards the pole.
It is estimated that about 18% of species in Europe, Central America, South Africa and Australia may disappear as a result of climate change.
2. Pesticides: Pesticides have helped in increasing agricultural yields but they have also affected biodiversity.
A number of these chemicals are not restricted to the areas where they are applied but can also spread through the air and water.
Some are said to be agents of evolutionary changes in some species.
a. Carbamates and organophosphates: These are toxic but do not have very long-lasting effects.
It can kill herbivorous birds that feed on plants that have been sprayed with these.
Dioxin has been implicated with birth defects and cancer in experimental animals.
b. Chlorinate Hydrocarbon Pesticides (CHs): These are stable so degradation is a problem as their effects can persist for years in the environment.
They are not soluble in water but are soluble in lipids and the implication is that aquatic organisms because they contain lipids take up these pesticides when they contaminate water bodies.
They have lethal or sub-lethal effects on organisms and also affect organisms other than the target forms.
Example is dichloro-diphenyl-trichloroethane (DDT) which can kill a number of pests including mosquitoes and effects more than the target organisms.
It bio-accumulates in animals. lt has been seen to be passed from seals to polar bears and to the cubs of the polar bears through the milk of their mothers.
DDT has been found to affect plants eaten by man like cassava and cashew. It has been banned in many countries.
It caused a weakening of the shells of eggs in some birds but with the ban there has been remarkable recovery.
3. Oil Pollution: Associated with oil exploration, production and transportation are spills and pollutions. A lot of spills have been reported all over the world eg. Persian Gulf (1991), Mexican platform (1979), Exxon Valdez off coast of Alaska (1989), BP Exxon Mobil (Nigeria,)
In the Exxon Valdez case it took about 4yars to clean up. Hot water was used in washing the shores and the oil and tar collected at the shores. The hot water killed a lot of invertebrates and spread the oil to initially unaffected shores.
4. Polynuclear Aromatic Hydrocarbons also known as polycyclic, PAH: These are the results of the combustions of fossil fuels and cigarette smoke. They are pollutants of the environment. They are mutate or damage RNA, DNA or proteins and can also bond with them resulting in cancer.
5. Polychlorinated Biphenyls (PCB): Are used as fire retardants and insulators and organic coolant. They are soluble in lipids and long lasting in the environment. They have negative effects on the reproduction of polar bears, seals and birds.
6. Heavy metals: E.g mercury, lead, zinc, nickel etc. are pollutants and have been incriminated in biomagnifications in food chains. They affect animals like fish and birds.
7. Radio-active pollutants: These have very negative effects on organism including man and the entire ecosystem because they are long lasting (Japan lsudamu March 2011).
8. Plastics: Major pollutants in the terrestrial and aquatic environments. Animals like sea turtles might ingest plastics mistaking them for jelly fish. Maser and Lee (1992) reported that 21 out of the 38 Spp of birds studied had individuals with plastics in their stomachs.
9. Light pollution: Trees have been observed to increase their growing season and this can expose them to the effects of winter frosts.
10. Disturbance activities: E.g. fires affect biodiversity, this affects the species that may be found in an area e.g the Cape floristic region in S/Africa depends on fires for seed dispersal. When fires break out it burns off the undergrowth of other species so new seeds can germinate and grow without competition.
11. Competition: between species it affects biodiversity through its effect on community structures.
In cases of fierce competition the stronger ones will exclude the weaker ones from a given area and this may reduce the diversity there.
Predation also controls to an extent the number of prey and this may favor a species over the others leading to a decrease in the population of the prey species preferred while non-prey species will be favored.
12. Exotic species: when this is introduced into a given area biodiversity is also affected.
An exotic species is one that does not occur naturally in a given area and is introduced knowingly or unknowingly through the activities of human beings.
Man can be referred to as a type of geological call force that is reshaping the landscape favouring some types of organisms and destroying others. Man’s activities have had the greatest impacts on biodiversity. Loss of species results in the functions of the ecosystem being dependent on fewer numbers of species.
For example Wetlands absorb excess water from rainfall, surging rivers and Act as giant sponges thereby preventing flooding (downstream).
This water will now be released with time. They absorb chemicals, filter out pollutants, sediments, neutralize harmful bacteria thereby cleaning the water.
Without these sediments, pollutants will find their way into the estuaries which are important as nurseries and feeding grounds for fresh and marine organisms. Unfortunately a good percentage of the world’s wetlands have been destroyed.
Due to the interactions and links between systems the loss of any will also affect the other changing the composition/nature of the atmosphere and starting new chain of negative processes.
Reasons for preserving Diversity: There are many reasons and this is also hinging on the importance of biodiversity.
1. Source of food for man e.g fish, plants, mushrooms, algae etc. almost all the protein (ducks, sheep, pigs, cattle, geese, turkeys, water buttaloes) from domesticated animals are form 9 species shell and finfish are now cultured. For Israel and China about half of their fish is from aquaculture.
About 90% of the world’s food comes from spp, e.g rice, corn, wheat supply about 2/3 of the need.
2. They are natural products/resources: A great number of things used by man e.g pesticides fertilizers, drugs are gotten and indirectly from plants and animals.
They like oil, coal, taxol used for ovarian cancer. Calabar bean was culturally used as a poison in West Africa.
About 121 prescription drugs are plant derivatives e.g codeine, quinine, morphine. Though chemicals produced by plants are toxic, if applied in the right dose or altered can be used to attack disease causative agents.
3. Biological Control Agents: There are organisms e.g Myxomatosis virus used in the control (rabbits introduced to Australia from ) pest/invasive species and this reduces the use of chemicals that will further harm the environment.
Many exotic organisms introduced by man into a system end up being serious pests.
4. They are the pool (Plants and animals) from which genes are obtained for genetic engineering (GM in genetic modification) and hybridization.
The sugar cane industry in US was saved from collapse by disease-resistance genes imported from Asian species.
In Africa and India the yield of cassava was increased through a disease resistance wild species brought from Brazil.
5. Inspiration: Scientific interest; biodiversity, encourages and inspires scientists in studies in different areas e.g anatomy, behavior, evolution, ecology, physiology etc. it also involves the inspiration to know about the natural world and to understand the workings and interrelations between living and non-living things.
It also inspires photographers, poets, writers, musicians and painters.
6. Self Perpetuation: Ecosystems that are biologically diverse aid in the preservation component species.
7. Environmental Services: Plants and animals are very important in environmental processes like, pollination (bees pollinate about a trillion apple blossoms in New York State every year.) Fertilization and soil aeration. Nutrient cycling and decomposition of wastes by Microorganism is also very important. Trees use up carbon dioxide releasing oxygen and thus maintaining stable climate and slowing down global warming.
Bio-remediation (Phyto if plants) is the use of organisms to clean up toxic wastes.
The extinction rate now is greater than it was about 65 million years ago.
This started about 10,000 years ago with the use of fire and invention of agriculture.
Break out
THE CONCEPT OF ENVIRONMENT
It can be said to be a complex of external factors that act on a system and determine their course and their way of existence.
An environment could be considered a superset in which the given system is a subset. It can consist of one or more parameters physical or other native.
The atmosphere of a given system must necessarily interact with living beings. The environment can be said to refer to most of the universe.
Environment can be said to be a system made up of natural and artificial components which are interrelated and are modified by the activities of humans.
It is made up of biological factors that is human, plants, water, animals and microbes.
Physical i.e geology, climate; and also socio-economic i.e urbanization, social conflicts, employment.
Business Dictionary defined Environment as the sum total of all surrounding of a living organism, including natural forces and other living things which provide conditions for development and growth as well as of danger and damage.
It also means surroundings (French word Environia) in which organisms live. It is the abiotic and biotic.
So there are two dynamic and complex parts of nature i.e the environment and the organisms.
Simply, it can also be said to be the materials and forces that surround a living organism.
Environment is the total conditions that surround humans at a given time and space.
It is made up of interacting systems of biological, physical and cultural matter that are inter-linked individually and collectively.
It is the sum total of conditions in which an organism has to survive or maintain its life process.
The environment affects (influence) the growth and development of living things.
Environment is made up mainly of the atmosphere, lithosphere, hydrosphere and biosphere.
It can also be divided into two types micro and macro, also Abiotic and Biotic.
Micro Environment- Is the immediate local surrounding of the organism.
Macro Environment -Is the abiotic and biotic conditions that surround the organism externally.
Physical Environment – This is all abiotic components i.e light, temperature, soil, rainfall, minerals etc. The atmosphere, hydrosphere, and lithosphere are also part of this.
Biotic- This is made up of the living components i.e plants, animals and microorganisms.
Abiotic -It includes the flow of energy needed to maintain any organism. The components include climate, temperature, oxygen etc.
The most significant changes to the environment are those generated by human beings through industrial and economic activities eg. Pollution, deforestation, urbanization, use of chemicals etc. which eventually change the climate.
The environment can also be said to be the set of circumstances that surround the outer form to a living being. The concept of environment can be in two main components:
1. Ecological subsets with defined boundaries which function as authentic natural systems of human intervention.
2. Universal resources that do not have borders defined like air, water. Environment can also be used to refer to a habitat i.e the natural environment of the camels (desert).
If the environment forms consistent functional natural units of plants4animals and micro-organisms then it is referred to as an Ecosystem.
Ecosystems include forests and deserts. Linked to the environment is Ecology.
It is the study of the relationship between organisms and their environment.
Ecological behavior protects environmental resources to secure the present and future livelihoods of humans and other organisms.
Ecological Footprints: It is the only metric that measures how much nature we have and how much nature humans use.
Footprints help individuals understand their impact on the planet, local leaders to optimize public project investments and countries to improve sustainability and well-being.
Ecological Footprint accounting measures the demand on and supply of nature.
For the demand, Ecological footprint measures, the ecological assets that a given population needs to produce the natural resources it consumes, this includes
plant based food and fibre products, fish and livestock products, forest products, space for the absorption of the wastes particularly carbon emissions and for urban infrastructure.
For the supply, a city, state or a nation’s Biocapacity represents the productivity of its ecological assets like grazing land, fishing grounds, forest land, cropland and developed land.
These areas if unharvested can absorb much of the waste (esp. Carbon emissions) generated by man.
Ecological Footprint and Biocapacity are expressed in Global hectares.
In this way it is globally comparable, standardized hectares with world average productivity.
The Ecological Footprint of any town, nation or country can be compared to its Biocapacity.
If the Ecological Footprint of a population is more than the biocapacity of the region the region will be on Ecological Deficit.
In this case, the demand for the goods and services provided by its seas, land, fruits, vegetables, wood, carbon dioxide absorption etc is more than what the ecosystems can renew.
When an area is undergoing ecological deficit it gets its needs through importation, liquidating its ecological assets e.g overfishing, emitting carbon dioxide.
If a region’s Biocapacitiy exceeds its Ecological footprint it has an Ecological reserve.
Mathis Wackernagel and William Rees conceived the Ecological Footprint in 1990 at the University of British Columbia.
This now matured into the broader Footprint movement which includes the carbon footprint now used by businesses, governments etc. to monitor ecological resource use and to advance sustainable development.
It is postulated that more than 80% of the world’s population live in countries experiencing Ecological deficits.
As at 2013 estimate by Global Footprint Network revealed that humanity has been using natural capital., 1.6 times as fast as nature can renew it.
Global Footprint Network calculates the ecological footprint from UN and other data for the world and over 200 nations.
Wikipedia defined Ecological Footprint as the measure of human impact of Earth’s ecosystem and reveals the dependence of the human economy on natural capital.
There is also the Ecological footprint analyses, (EFA) or Per capita ecological footprint (EF).
This is a means of comparing consumption and lifestyles and then checking this against the ability of nature to provide the consumption.
The ecological footprints are measured in 2 ways:
(a) To measure ecosystem displacement and the definition is City Area minus remaining green spaces.
It is an area measurement which does not include human or other biological activity.
(b) This method quantifies surviving ecosystem health i.e attempting to quantify surviving ecosystem health i.e quantifying both area and biological health of ecosystems surviving in the city areas eg. Parks, nature reserves and other green spaces.
ENGERGY EXPLORATION AND EXPLOITATION IMPACTS ON DIVERSITY
1. Wind Energy: From studies there are impacts of the exploration and exploitation of this energy on animals like bats and birds.
There are also impacts from re-powering i.e exchanging small old wind turbines by new big turbines.
(a) Disturbance leading to displacement/exclusion and collusion mortality.
Some birds (the waders) that nest on open grounds can be displaced by wind farms.
The negative impacts on the non-breeding birds were more pronounced e.g lapwings, geese, golden plovers.
Many birds on the contrary especially Passerines preferred to settle closer to bigger, than to smaller wind turbines for breeding.
During the non-breeding season many species of open landscapes avoided approaching wind parks that were closer than a few hundred metres.
For geese the disturbance can occur at least up to 500m from wind turbines.
For most of them the distances at which disturbance could be observed increased with the size of the wind turbines.
For some species there might be a “barricade” affect eg. Geese, waders, common cranes and small passerines (especially during migration).
2. Collusion rates -some studies have shown that it can be between 0 and more than 50 collisions per turbine per year for birds and bats.
The habitats affected the number of collusions. The risks were higher for birds at wind farms close to wet lands. E.g gulls and also wind farms on mountain ridges. For bats wind farms in or close to forests had high collision risks, and this increased with increasing size of the wind turbine.
This was mostly in late summer or autumn during migration and dispersal.
The effects of repowering with the new large wind turbines may reduce the negative impacts on bats and birds (i.e if many small turbines are replaced by few big turbines) but if the wind farm capacity is doubled etc. the negative impacts increase.
Solar Energy: Usage of this form of energy has increased. Solar parks covering several hectares are being put up. There may be two possible impacts
(a) Displacement of breeding and non-breeding birds, and bats from the area of the solar parks.
(b) Collision mortality.
Especially for birds, the reflective surfaces of solar cells could imitate areas of water to which the birds are attracted. The likely victims are waders and water fowls which migrate mainly at night. (This might not be significant).
The impacts on breeding birds have not yet been fully studied. It is just projected that the sensitive species of open habitats will not remain in the solar parks.
Energy Crops: Generally, there are two main potential ways of using plants as energy crops i.e. the extraction of oil for fuel and using whole plants for fermentation or for direct combustion.
Oil Crops -Fuels are being extracted from sunflowers and oil-seed rape.
Their cultivation is same as for agricultural processes. As a winter – sown crop with a more or less complete surface cover it provides food for some birds especially large wintering species like geese, swans and wigeon outside the breeding season.
The rape plants, are rapid growing and grow very close together in spring, farmland birds e.g. quail, and grey partridge etc. avoid them. As a result of this second or replacement broods are hardly possible.
Birds like skylarks avoid sunflower fields during the breeding season.
Fields of sunflower stubble are valuable food sources for granivorous songbirds and pigeons.
Many farmland birds need a minimum degree of diversity in countryside management (NABU, 2004).
With cultivation of sunflower and oil-seed rape for production of oil causes a widespread standardization of crop, structure, negative impacts on the populations should be expected.
Woods -Fast growing trees e.g. willows and poplins (even mangroves can be practiced in Niger Delta) are cultivated in some countries for wood fuel.
The tree crop can be harvested after 3- 5 years, when the stems have reached about 5 m high (Studies in this area are limited).
An increase in the cultivation of maize can result in decline in farmland bird diversity because it is uninhabitable for most farmland birds, though it can be used by ground breeding species shortly after sowing.
Coal Power: The power is a major source of
a) emission of 1 CO2 which is also a big culprit in global warming. A coal plant can emit 3.5 million tons of CO2 per year.
b) Sulphur dioxide emission also affects public health, and is also involved in the formation of small acidic particulates that can enter into the lungs and then into the blood. Acid rain damages soils, crops, aquatic ecosystems forests etc.
c) Nitrogen oxides -causes smog or ground level ozone. This enhances asthmatic attacks and also affect lungs. Without a control a coal plant can produce 10,300 tons per year.
d) Mercury -It is released and causes brain damage and heart problems. It is very toxic.
e) Particulate matter (soot/fly ash) –can aggravate asthma, may cause bronchitis and can even cause death.
Other substances like cadmium, lead, trace amounts of uranium, carbon monoxide, arsenic, etc. are also released.
Nuclear Power: The impact is mainly from the nuclear fuel cycle and from nuclear accidents.
Green house gas emissions though it is lower than that from oil and coal.
If the nuclear reactors fail, through melting of overheated fuels and the release of large amount of fission products.
The negative impacts are long lasting even affecting humans directly and indirectly affecting reproductive structures and foetuses.
Hydroelectric Power: This involves construction of dams, change in water flow etc.
a) The size of the reservoir depending on the size requires land/water.
b) They have major impacts on the aquatic ecosystems. Fish and other aquatic organisms can be injured and killed by the heads of the turbine.
c) Water in the reservoir is more stagnant than that of the normal river.
Due to this, there are more sediments and nutrients in the reservoir. This can result into an excess of algae and aquatic weeds.
d) Loss of water through evaporation from the reservoirs at a rate higher than that of flowing water bodies.
Also if too much water is stored behind the reservoir, parts of the river downstream may dry up.
So from time to time the operators release minimum amount of water at certain times of the year.
If this is not carried out and the water level drops it can cause harm to plants and animals.
e) Water in the reservoir is characterized with low dissolved oxygen and is colder.
Its release could affect water downstream and therefore the plants and animals negatively.
f) Installation and dismantling of hydroelectric power plants can lead to Global warming emissions.
Thank you for your audience
Assignment:
Discuss ways one can actively participate in conservation of biodiversity. Max of 4 pages to be submitted on Tuesday 20th August, 2021
Send to: gentle.komi@uniport.edu.ng
