A slideshow on the meaning, types and components of an Ecosystem.

This slideshow contains the entire syllabus covered under First year of Environmental Science elective by the University of Delhi.

1. ECOSYSTEMS
ENVIRONMENTAL SCIENCE
KAMALA NEHRU COLLEGE
ANURAG CHAUHDARY

2. Concepts

3. ECOLOGY
“ Scientific study of the relationship of living organisms with each other and with their
environment “
Ecology deals with the study of organisms in their natural home interacting with their
surroundings.
Oikos = Home; logos = study
Coined by = Ernst Haeckel, 1869
Father of modern ecology = Eugene P. Odum

4. ECOSYSTEM
Anecosystemisacommunityofdifferentspeciesinteractingwithoneanotherand
withtheirnonlivingenvironmentofsoil,water,otherformsofmatter,andenergy,
mostlyfromthesun.
Anecosystemisaself-regulatinggroupofbioticcommunitiesofspeciesinteracting
withoneanotherandwiththeirnon-livingenvironmentexchangingenergyand
matter.
Ecosystemshowlargevariationsintheirsize,structure,compositionetc.however,all
ecosystemsarecharacterizedbycertainbasicstructuralandfunctionalfeatures
whicharecommontoall.

5. 1 2
3
4

6. CHARACTERISTICS OF AN ECOSYSTEM
Natural or Artificial
Variable in size
No clear boundary
Not isolated from each other
Matter and Energy move from one ecosystem to another
Concept given by A. G. Tansley, 1935
STRUCTURAL AND FUNCTIONAL UNIT OF BIOSPHERE

7. 1. STRUCTURE OF ECOSYSTEM
The nature of a ecosystem depends on :
Geographical features of the region
Climatic conditions
Soil and water characteristics
Communities of plants, animals, microbes to live in specific conditions
An ecosystem structure includes both biological (biotic) and non-living
(abiotic) components.
ABIOTIC
COMPONENTS
BIOTIC
COMPONENTS

8. 1.i. ABIOTIC COMPONENTS
All physical and chemical components i.e. the NON LIVING COMPONENTS
The physical and chemical components of an ecosystem constitute its abiotic structure
SOLAR ENERGY
WATER
AIR
SOIL
CLIMATIC FACTOR
NUTRIENTS
MOST IMPORTANT determinants of where and how well an organism exist in its environment

9. ABIOTIC COMPONENTS
RANGE OF TOLERANCE : It is the stretch in an ecosystem where all the
necessary abiotic factors are in optimum level for population growth

10. ABIOTIC COMPONENTS
LIMITING FACTOR PRINCIPLE
“ Too much or too little of any abiotic factor can limit or prevent growth of a
population, even if all other factors are at or near the optimal range of
tolerance ”
LIEBIG’s LAW OF MINIMUM

11. ABIOTIC COMPONENTS
The limiting abiotic factors :
Sunlight/Energy
Solar flux and duration of solar radiation
Average temperature
Geographical position
Rainfall and water availability
Substratum/Soil
Salinity of water
Dissolved gases in water
Essential nutrients viz. C, N, P, K, H, O, S etc.

12. 1
23

13. 1.ii. BIOTIC COMPONENTS
Alllivingbeingsintheecosystemi.e.plants,animals,microbes,etc.
Allthebioticcomponentsofanecosystemareinfluencedbytheabiotic
componentsandviceversa,andtheyarelinkedtogetherthrough
energyflowandnutrientcycling.
Theyareclassifiedinto:
a)Primaryproducers
b)Consumers
c)Decomposers

14. 1.ii.a. Primary Producers
Autotrophsorself-feeders
Maketheirownfooddirectlyfromtheenvironmentbytheprocessof
photosynthesisorchemosynthesis.(Sunlight,Water,CarbonDioxide,inorganic
compounds,etc.)Canutilizeonly1%ofsolarenergy
Greenplants,Aquaticgreenplantsandalgae,Phytoplankton,specialized
bacteria

15. Primary Producers
PhotosyntheticorganismsbytheprocessofPHOTOSYNTHESIS
Chemosyntheticorganismsconvertsimpleinorganiccompounds fromtheir
environmentintomorecomplexnutrientcompoundswithoutusingsunlightby
theprocessofCHEMOSYNTHESIS.E.g.Specializedbacteriainandaround
hydrothermalvents.
Green plants, algae, etc. having
chlorophyll pigment.

16. 1.ii.b. Consumers
HeterotrophsorotherfeedersorPHAGOTROPHS
Can’tproducetheirownfooddirectlyfromtheenvironment,feedsonother
organismstoobtaintheirnutrients
Thereareseveraltypesofconsumers:
Primaryconsumers
Secondaryconsumers
Tertiaryconsumersandsoon…

17. Consumers
Primaryconsumers:planteatersorherbivores.E.g.Cows,Goats,Zooplanktons,etc.
Secondaryconsumers:meateatersorcarnivores.E.g.Hyenas,Frogs,Zooplankton
eatingfishes,etc.
Tertiaryconsumers:Highlevelcarnivores.E.g.Tigers,Wolves,Sharks,etc.
Omnivores:Feedonbothplantsandanimals.E.g.Human,Cockroaches,Fox,Pigs,
etc.

18. 1.ii.c. Decomposers
SAPROTROPHSorOSMOTROPHS:feedsuponandbreaksdownanddecompose
deadorganicplantoranimalmatter.
Theycanbe:
Detritivores:feedsondeadmatterofplantsandanimals.E.g.Butterflies,Beetles,Termites,
earthworms,etc.
Saprophytes:decomposedeadorganicwastetosimplerinorganicformsbythehelpof
enzymeswhichcanagainusedbytheautotrophs.E.g.Fungi,Bacteria,Microorganisms,
etc.

20. 2. FUNCTIONS OF ECOSYSTEM
i.Energy Flow through food chain/food web. (Physical function)
ii.Nutrient Cycling (Biogeochemical cycle)
iii.Productivity
iv.Homeostasis or feedback control mechanisms.
v.Ecological succession or Ecological development.
Food chain, Food Web, Ecological Pyramids.

21. 2.i. ENERGY FLOW
Forceforallmetabolicactivities.
EnergyFlowisfromproducertotopconsumer.Itflowsfromalltrophiclevelsandisalways
fromlowertrophicleveltohighertrophiclevel.
Energyflowisalwaysunidirectional.
Lossofenergyateachtrophiclevelintheformofunusableheati.e.itdecreasesfromthe
firsttrophiclevelupwards.(Only10%ofenergymovestohighertrophiclevels–LINDEMAN’S
LAW).
Thepercentageofusablechemicalenergytransferredasbiomassfromonetrophiclevel
tothenextiscalledecologicalefficiency.

22. ENERGY FLOW
There are 3 ways to assess the energy flow in an ecosystem:
a)Food Chain
b)Food Web
c)Ecological Pyramids

23. 2.i.a. FOOD CHAIN
Organismsintheecosystemarerelatedtoeachotherthroughfeedingmechanism.
Asequenceoforganismsthatfeedononeanother,formafoodchain.
“Transferoffoodenergyfromgreenplants(producers)throughaseriesoforganisms
withrepeatedeatingandbeingeateniscalledafoodchain”
Grasses→Grasshopper→Frog→Snake→Hawk/Eagle
Thenumberoftrophiclevelsarelimitedinanyfoodchain.

24. Theproducersandconsumersarearrangedintheecosysteminadefinitemanner
andtheirinteractionalongwithpopulationsizeareexpressedtogetherastrophic
structure.
Eachfoodlevel/stepisknownastrophiclevel.
Theamountoflivingmatterateachtrophiclevelatagiventimeisknownas
standingcroporstandingbiomass.
FOOD CHAIN

25. FOOD CHAIN
Twotypes(asperthesourceofenergyforthe1
st
consumer):
GRAZINGFOODCHAIN
Theconsumerswhichstartthefoodchainutilizingplantastheirfood.Itbeginsfromgreen
plantsandtheprimaryconsumerisherbivore.
DETRITUSFOODCHAIN
Theconsumerswhichstartthefoodchainutilizingdeadorganicmatterastheirfood.It
beginsfromthedeadorganicmattertothedetrivoreorganismswhichinturnmakefoodfor
protozoantocarnivores.Ithelpsinnutrientcycling.

26. Grazing food chain v/s Detritus food chain

27. Grazing food chain v/s Detritus food chain
These two chains are not isolated but rather are linked with each other

28. 2.i.b. FOOD WEB
Trophiclevelsinanecosystemarenotlinearrathertheyareinterconnectedand
makeafoodweb.
“Afoodwebillustratesallpossibletransfersofenergyandnutrientsamongthe
organismsinanecosystem.”
Providesalternativepathwaysfortransferofenergyinanecosystem,thereby
increasingthechancesofsurvivalofspecies,regulatingthepopulationsize.

29. Antarctic food web

30. FOOD CHAIN v/s FOOD WEB

31. 2.i.c. ECOLOGICAL PYRAMIDS
Thestepsoftrophiclevelexpressedinadiagrammaticwayarereferredasecological
pyramids.
Itisdepictedbyhorizontalbarslayeredupononeanotherwitheachbarrepresenting
onetrophiclevel.
Thelengthofeachbardenotesthetotalnumberofindividualsatthattrophiclevel.
Thebaseisformedbyfoodproducers,thetipisformedbythetopcarnivorewith
otherconsumersinbetween.

33. ECOLOGICAL PYRAMIDS
The Ecological Pyramids are of three categories:
Pyramid of numbers
Pyramid of biomass
Pyramid of energy/productivity.

34. Pyramid of Numbers
DealswiththerelationshipbetweenthetotalNUMBERSofprimaryproducersand
subsequentconsumersatdifferenttrophiclevelsinanecosystem.
Canbeuprightorinvertedorofanyshape.
Pyramidofnumbers-upright=Grasslandecosystem,Pondecosystem
Pyramidofnumbers-inverted/spindleshape=ParasiticTreeEcosystem,Nonparasitictree
ecosystem.

35. Pyramid of numbers -Upright
The number of individuals is decreased from lower trophic level to higher
trophic level.
E.g. Grassland ecosystem
Pond ecosystem
Rotifers

36. The number of individuals is increased from lower level to higher trophic
level.
The base is represented by producers which are lesser in number than
dependent herbivores.
E.g. Parasitic Tree ecosystem
Pyramid of numbers –Inverted/spindle
shaped

37. The drawbacks of pyramid of numbers are:
It does not take into account the fact the size of organisms being counted in
each trophic level can vary.
It is very difficult to count the number of all the organisms in a particular trophic
level.
Hence, the pyramid of number does not completely define the trophic
structure for an ecosystem.
Pyramid of Numbers

38. Pyramid of Biomass
To overcome the shortcomings of pyramid of numbers, pyramid of
BIOMASS is used.
Individuals in each trophic level are weighed instead of being counted.
Deals with the relationship between the total DRY WEIGHTof primary
producers and subsequent consumers at different trophic levels in an
ecosystem.
Can be upright or inverted.

39. The biomass of the producers is maximum, hence, the base is long and
large. The biomass of the next trophic level i.e. the primary consumers is
lesser than the producers and so on.
E.g. Pyramid of biomass of
most land based ecosystems.
Pyramid of biomass -Upright

40. The biomass of the producers are lesser than the subsequent consumers,
hence, the base is small, thus the pyramid assumes inverted shape.
E.g. Pyramid of biomass of
an Aquatic Ecosystem
Pyramid of biomass -Inverted

41. Pyramid of Energy
It is the most suitable tool to compare the functional roles of the trophic system
in an ecosystem.
Conversion of solar energy to chemical energy.
Loss of energy as heat energy at each trophic level, so the subsequent trophic
level has lesser energy than the previous one.
ALWAYS UPRIGHT
Energy pyramid concept helps to explain the phenomenon of biological
magnification.

42. Pyramid of Energy

43. FEW EXTRA CONCEPTS:
Some concepts which are related to trophic structure of an ecosystem:
Bioaccumulation
Biomagnification
Biotic interaction

44. BIOACCUMULATION
It refers to how pollutants enter a food chain.
It is the increase in the concentration of a pollutant from the environment
to the first organism in a food chain.
The pollutants must be non-degradablein nature i.e. they cant be
metabolized by the living organisms.
E.g. Chlorinated hydrocarbons, DDT, Diclofenac, etc.

45. BIOMAGNIFICATION
Pollutants move through various trophic levels in an ecosystem.
Biomagnification refers to the tendency of pollutants to concentrate as
they move from one trophic level to the next.
Concentration of the pollutants increases as we move upwards in the
trophic level.

46. BIOMAGNIFICATION
The pollutant must be:
Non biodegradable
Long lived
Mobile
Soluble in fats
Biologically active
E.g. Diclofenac poisoning in vultures, etc.

47. BIOTIC INTERACTION
Living organisms in this Earth are interlinked with each other in one way or
other.
This interaction between the organisms is fundamental for its survival and
functioning of Ecosystem as a whole.
Types of Biotic interaction are:
Mutualism
Commensalism
Amensalism
Competition
Predation
Parasitism

48. MUTUALISM:-both species are benefitted. E.g. Pollination by bees.
COMMENSALISM :-one species is benefitted, the other remains unaffected.
E.g. Cow dung and Cow dung beetles.
AMENSALISM:-one species is harmed, the other remains unaffected. E.g.
Antibiosis between penicillium mould and bacteria.
COMPETITION:-both species are harmed. E.g. two species eating the same
food.
PREDATION/PARASITISM :-one species is benefitted, the other one is harmed.
E.g. Tiger killing a bison.
BIOTIC INTERACTION

50. 2.ii. NUTRIENT CYCLING
The elements and compounds that make up nutrients move continually
through air, water, soil, rock, and living organisms in ecosystems/biospheres in
cycles which is called biogeochemical cycles (literally, life-earth-chemical
cycles) or nutrient cycles.
A concept that describes how nutrients move from the physical environment to
the living organisms and subsequently recycled back to the physical
environment.

51. Essential for life and its vital function of ecology.
For maintenance of sustainable population in a particular ecosystem.
C, H, O, N and P as elements and compounds make up 97% of the mass of
our bodies and are more than 95% of the mass of all living organism.
Based on the nature of the reservoir, there are two types of cycles:
Gaseous cycle-where the reservoir is the atmosphere of the hydrosphere. E.g.
water, carbon, nitrogen
Sedimentary cycle-where the reservoir is the earth’s crust. E.g. Phosphorous
NUTRIENT CYCLING

52. WATER CYCLE (Hydrological cycle)
Continuous circulation of water in the Earth-atmosphere-hydrosphere system in
all forms (Global cycle).
The water cycle is powered by solar energy and involves three major
processes—evaporation, precipitation, and transpiration.
Major reservoirs are atmosphere, oceans, lakes, rivers, soils, glaciers, snowfields,
groundwater, etc. The largest reservoirs/sink are the oceans.
Moves from one reservoir to other by the process of evaporation, transpiration,
precipitation, runoff, infiltration, etc.

53. WATER CYCLE (Hydrological cycle)

54. CARBON CYCLE
Carbon is vital for life to sustain in Earth.
Production of carbohydrates through photosynthesis.
Component of DNA
Formation of coal
It is divided into two parts:
Short term cycle via atmosphere
Long term cycle via accumulation in the aquatic systems.
Oceans are the largest reservoir of carbon.

55. CARBON CYCLE

56. Short term cycle:
In the form CO2 in the atmosphere.
Exchange of carbon between atmosphere and organism via the processes of
photosynthesis, respiration and decomposition.
Long term cycle:
Accumulation as un-decomposed organic matter in peaty layers of marshy soils
OR as insoluble carbonates in bottom sediments of aquatic systems which takes a
longer time to be released.
Trapped in fossil fuels such as coals, oils, natural gases
When used its released back into the atmosphere.
CARBON CYCLE

57. NITROGEN CYCLE
Nitrogen Cycle is a biogeochemical process through which nitrogen is
converted into many forms, consecutively passing from the atmosphere to
the soil to organism and back into the atmosphere.
Essential constituent of protein and is a basic building block of all living
tissues.
Nitrogen exists in both organic and inorganic forms.

58. Atmosphere is the largest reservoir of nitrogen.
Elemental form of nitrogen can not be used directly by most of the living organisms.
Hence, nitrogen has to be FIXED and then converted into other forms viz. ammonia
(NH3), nitrites (NO2-), nitrates(NO3-) before taken up by plants.
5 processes:
Fixation
Nitrification
Assimilation
Ammonification
Denitrification
NITROGEN CYCLE

59. Nitrogen Fixation
Atmospheric nitrogen (N2) which is primarily available in an inert form, is
converted into the usableform –ammonium ions (NH4+).
Nitrogen fixation is accomplished by three different ways :
By Biological fixation (Diazotrophs –symbiotic bacteria. E.g. Rhizobium, Azatobactor,
etc. ) NITROGENASE ENZYME.
By atmospheric phenomenon as thunder and lightening
By man using industrial processes

60. NITROGEN CYCLE
Nitrification
2NH
4
+
+3O
2→ 2NO
2
–
+ 4H
+
+ 2H
2O
2NO
2
–
+ O
2→ 2NO
3
–
Assimilation
Ammonification : thenitrogen present in the organic
matter is released back into the soiland is converted
back into Ammonia.
Denitrification : Denitrification is carried out by the
denitrifying bacterial species-Clostridium and Pseudomonas,
which will process nitrate to gain oxygen and gives out free
nitrogen gas as a byproduct.

61. NITROGEN CYCLE

62. PHOSPHOROUS CYCLE
Phosphorus cycle is a biogeochemical process that involves the movement of
phosphorus through the lithosphere, hydrosphere and biosphere.
It forms a significant part of the structural framework of DNA and RNA, and
important component of ATP.
Very slow process-sedimentary cycle. (EARTH CRUST-largest reservoir)
Various processes help to wash the phosphorus present in the rocks into
thesoil. Phosphorus IN THE FORM OF PHOSPHATESis absorbed by the organic
matter in the soil which is used for various biological processes.

63. Following are the important steps of phosphorus cycle:
Weathering of Phosphate (PO43-) containing rocks. E.g. Phosphorite
Absorption by Plants and Animals
Return to the Environment through Decomposition
PHOSPHOROUS CYCLE

64. PHOSPHOROUS CYCLE

65. SULPHUR CYCLE
Sulfur cycle is the circulation ofSulphurin various forms through nature.
Component of proteins and amino acids.
Sulphur is released into the atmosphere by:
Burning of fossil fuels in the form of Sulphur dioxide (SO2).
Volcanic activities (SO2 and H2S)
Decomposition of organic molecules
Weathering of sulphates (SO42-) containing rocks. MARINE SEDIMENTS ARE THE
LARGEST RESERVOIR OF SULPHUR.

66. SULPHUR CYCLE

67. ACTIVITY: POINTS TO PONDER
ANTHROPOGENIC
ACTIVITIES AND ITS
IMPACT
OVERUTILIZATION
of RESOURCES
POLLUTION???
RELEVANT
EXAMPLES !!!!
AGRICULTURE
CLIMATE
CHANGE BIODIVERSITY
THREAT

68. 2. iii. PRODUCTIVITY
The rate of biomass production is called productivity.
Productivity is a rate function and is expressed in terms of dry matter
produced or energy captured per unit area of land, per unit time.
It can be expressed as:
energy in calories/cm
2
/yr.
dry organic matter in g/m
2
/yr.
The productivity of different ecosystems can be easily compared.

69. FACTORS AFFECTING PRODUCTIVITY
Solar radiation and temperature.
Moisture, i.e. soil moisture, fluctuation of precipitation, and transpiration.
Mineral nutrition.
Biotic activities.
Impact of human populations

70. 2.iii.a. PRIMARY PRODUCTIVITY
It is the rate at which radiant solar energy is converted into chemical organic
substance by photosynthesis or chemosynthesis by the primary producers.
It has two aspects:
Gross primary productivity (GPP)-The total solar energy trapped in the food material
by photosynthesis/chemosynthesis.
Net primary productivity (NPP)-The amount of energy-bound organic matter created
after respiration.
NPP = GPP-Respiration.

71. Productivity of Ecosystems

72. 2.iii.b. SECONDARY PRODUCTIVITY
The rates at which the heterotrophic organisms resynthesize the energy-
yielding substances are called secondary productivity.
The amount of organic matter stored by herbivores or carnivores is known
as secondary production.

73. 2.iv. ECOLOGICAL HOMEOSTASIS
Thetendency of a biological system to resist changes.
Maintain itself in a steady equilibrium state i.e. in balanced state.
“ Ecological/Ecosystem Homeostasis is its inherent property resist change”

74. Homeostasis
Homeostasis is themaintenance of stable equilibrium, especially through
physiological (through bodily part functions). E.g. Cooling your body
through sweating processes.
Organisms try to maintain the constancy of its internal environment despite
varying external environmental conditions that tend to upset their
homeostasis.
Negative (-ve) feedback loops-Deviation counteracting mechanisms.
Positive (+ve) feedback loops-Deviation accelerating mechanisms.

75. Homeostasis

76. -ve feedback loop example:-

77. NEGATIVE FEEDBACK LOOPS =
INHIBITION
POSITIVE FEEDBACK LOOPS =
PROMOTION

78. Positive feedback loops example :-

79. Homeostasis mechanisms:
Regulate
Conform
Migrate
Suspend

80. Regulate
Control or Regulation.
Some organisms can maintain homeostasis by physiological functions.
E.g. Thermoregulation by warm blooded animals. Mammals and birds
ENDOTHERMS

81. Conform
An overwhelming majority of animals and nearly all plants cannot maintain
a constant internal environment. Their body temperature changes with the
ambient temperature
ECTOTHERMS

82. Migrate
The organism can move away temporarily from the stressful habitat to a
more hospitable area and return when a stressful period is over.
E.g. Keoladeo National Park, Bharatpur, Rajasthan-Migration of Siberian
Crane

83. Suspend
Suspend metabolic activities.
E.g. Hibernation
Aestivation.

84. ECOSYSTEM HOMEOSTASIS
All Ecosystems regulate and maintain themselves under a set of environmental
conditions to achieve a steady state of DYNAMIC EQUILIBRIUM.
If any stress tries to cause a deviation, then the system has its own mechanisms to
counteract these deviations which are known as –ve feedback mechanisms.
E.g. In a pond ecosystem, if the population of zooplankton increases, they consume
a large number of the phytoplankton and as a result, food would become scarce
for zooplanktons. When the number of zooplanktons is reduced because of
starvation, the phytoplankton population start increasing. After some time, the
population size of zooplankton also increases.

85. ECOSYSTEM HOMEOSTASIS

86. The homeostatic capacity of ecosystems is not unlimited as well as not
everything in an ecosystem is always well regulated.
If the stress is too high positive feedback mechanisms start operating which
leads to death of species and collapse of the ecosystem.
E.g. Human activities impact
ECOSYSTEM HOMEOSTASIS

87. 2.v. ECOLOGICAL SUCCESSION
Communities are dynamic, changing more or less regularly over time and
space.
Variations in climatic factors
Activities of the species of the communities themselves
Human interventions
Occurrence of relatively definite sequence of communities over a period of
time in the same area until a stable, mature community develops (CLIMAX
COMMUNITY) is ECOLOGICAL SUCCESSION.
ECOLOGICAL DEVELOPMENT

88. ECOLOGICAL SUCCESSION

89. ECOLOGICAL SUCCESSION
Orderly and continuous changing process
Reasonably directional
Somewhat predictable.
Not unlimited
It culminates in a stabilized ecosystem in which maximum biomass and
functions between organisms are maintained per unit of available energy.

90. Primary v/s Secondary Succession
Primary Succession
Starts from primitive substratum, where there was no previously any sort of
living matter.
The first group of organisms establishing there are known as PIONEERS/
Primary Community/Primary Colonizers.
Secondary Succession
Starts from previously built up substrata with already existing living matter.
Are relatively rapid

91. GENERAL PROCESS OF SUCCESSION
NUDATION
INVASION
COMPETITION and COACTION
REACTION
STABILISTION (CLIMAX)

92. NUDATION
Development of a bare area without any form of life
They area may develop due to:
TOPOGRAPHIC-soil erosion, landslide, etc.
CLIMATE-glaciers, dry period, fire.
BIOTIC-man made

93. INVASION
Successful establishment of a species in a bare area
Species actually reaches this new site from any other area
Migration
Establishment-ecesis
Aggregation

94. Competition and Coaction, Reaction
and Stabilization
Competing for space and nutrients.
Reaction-modification of the environment
The sequence of communities that replaces one another in the given
area is called a SERE, and various communities constituting the sere are
called SEREAL STAGES.
Stabilization (Climax)-Climax community and this stage is climax stage

95. HYDROSERE or HYDRARCH

96. HYDROSERE or HYDRARCH

97. XEROSERE or XERARCH

98. ECOTONE
Ecotoneis a transitional area between two biological communities such
asforest andgrassland. E.g. Estuaries, mangrove ecosystem, etc.
It contains a large variety of species of fauna and flora as the area is
influenced by both the bordering ecosystems.
It may be wide or narrow
It could contain species that are entirely different from those found in the
bordering systems
Ecotones can be natural or man-made. For example, the ecotone between
an agricultural field and a forest is a man-made one

99. ECOTONES

100. ECOTONES
Edge effects refer to the changes in population or community structures that
occur at the boundary of two habitats. Generally, there is a greater number of
species found in these regions (ecotones) and this is called the edge effect.
The species found here are callededge species.
They can act as buffer zones offering protection to the bordering ecosystems.
They serve as a bridge of gene flow from one population to another because
of the larger genetic diversity present.
Ecotones are also a sensitive indicator of global climate change