This document is a report authored by seven students from the Department of Computer Science at Karunya University on the topic of biodiversity in their campus. It summarizes research showing that biodiversity provides essential benefits and ecosystem services but is threatened by various physical and policy-related factors. The report examines theories on the relationship between biodiversity and ecosystem function, such as the sampling effect and niche complementarity hypotheses. It also explores how more diverse ecosystems may be more resilient to environmental fluctuations through the insurance effect.

1. BIODIVERSITY IN OUR CAMPUS
BEZALIN RAJ.R (UR16CS153)
AKHIL ANTONY (UR16CS154)
JOEL RAJ BATHULA (UR16CS155)
GAUTHAMLAL T.V (UR16CS156)
ANIKETH SAHA (UR16CS157)
C.ALVINO ROCK (UR16CS158)
LIVIN P.KURIAKOSE (UR16CS159)
FINAL REVIEW

2. IF BIODIVERSITY IS SO PRECIOUS AND
IMPORTANT, THEN WHY IS IT SO
THREATENED?• DISTINGUISH BETWEEN PHYSICAL AGENTS OF BIODIVERSITY LOSS, AND THE
UNDERLYING POLICY AND SOCIAL REASONS
• EXISTENCE OF TRADE-OFFS- THOSE ACTIONS HARMFUL TO ONE COMPONENT OF
NATURE ALSO PROVIDE VALUABLE SOCIETAL BENEFITS
(TILMAN 1999)
• MUCH OF CURRENT ENVIRONMENTAL POLICY IS ROOTED IN POLICY DEVELOPED
FOR AN OLDER AND MUCH DIFFERENT WORLD
DEPARTMENT OF COMPUTER SCIENCE,
KARUNYA UNIVERSITY

3. "On average, plants contain less than half a gram of
carbon per square metre. Yet this thin veneer of living
matter sandwiched between a 100km deep lithosphere and
a 100-km high atmosphere manages to cycle about 60
gigatonnes (60 x 1015
) of carbon per year between the
biosphere, lithosphere and atmosphere. Clearly the Earth's
biota has staggering capability to affect our environment.”
But this perspective overlooks a critical feature of plant
life: this green slime consists of more than a quarter of a
million species. What, if any, is the role of such
extraordinary diversity? ” Naeem [1999]
Experimental reductions in biodiversity
DEPARTMENT OF COMPUTER
SCIENCE,KARUNYA UNIVERSITY

4. Ecosystemfunction
Species richness
low highlow high low high
Redundant Rivet Idiosyncratic
Hypothetical relationships between diversity and ecological processes
DEPARTMENT OF COMPUTER
SCIENCE,KARUNYA UNIVERSITY

5. RELATIONSHIP BETWEEN DIVERSITY
AND FUNCTION• NULL HYPOTHESIS: ECOSYSTEM FUNCTION IS INSENSITIVE TO SPECIES ADDITIONS OR DELETIONS (THE TRIVIAL CASE)
DEPARTMENT OF COMPUTER
SCIENCE,KARUNYA UNIVERSITY
Ecosystem
function
Species richness
low high

6. WHAT ARE ECOSYSTEM EFFECTS OF A REDUCTION IN DIVERSITY?
• RIVET: ALL SPECIES CONTRIBUTE TO THE INTEGRITY OF AN ECOSYSTEM IN A SMALL BUT SIGNIFICANT WAY SUCH THAT A PROGRESSIVE
LOSS OF SPECIES STEADILY DAMAGES ECOSYSTEM FUNCTION.
DEPARTMENT OF COMPUTER
SCIENCE,KARUNYA UNIVERSITY
Ecosystem
function
Species richness
low high

7. Decreasing species richness (log2 scale)
DEPARTMENT OF COMPUTER SCIENCE,
KARUNYA UNIVERSITY

8. • THE PREVIOUS SLIDE SHOW THE RELATIONSHIP BETWEEN DIVERSITY AND
ABOVEGROUND BIOMASS AT EACH OF THE LOCAL SITES (COUNTRIES). WHEN
EACH DATA SET FROM INDIVIDUAL SITES WERE ANALYSED INDIVIDUALLY, THE
RELATIONSHIP WAS BEST DESCRIBED BY A VARIETY OF MODELS: LINEAR
(PORTUGAL AND SWITZERLAND); CURVILINEAR ( GERMANY, SWEDEN,
SHEFFIELD); ANOVA (IRELAND AND SILWOOD).
DEPARTMENT OF COMPUTER
SCIENCE,KARUNYA UNIVERSITY

9. EXPLANATIONS FOR DIFFERENCES
BETWEEN SINGLE SITES AND
META-ANALYSIS
• (I) ALL SITES CONFORM TO THE SAME UNDERLYING PATTERN SEEN IN THE OVERALL
ANALYSIS, AND DIFFERENCES BETWEEN INDIVIDUAL SITES ARE DUE TO REDUCED SAMPLE
SIZE AND STATISTICAL POWER
• (II) SITES DO DIFFER IN THEIR RESPONSES, BUT THE OVERALL ANALYSIS IS NOT POWERFUL
ENOUGH TO REVEAL A SIGNIFICANT LOCATION-BY-SPECIES RICHNESS RELATIONSHIP
• (III) A SIGNIFICANT GENERAL PATTERN EMERGES DESPITE DIFFERENCES IN DETAIL AT
INDIVIDUAL LOCATIONS; WHILE AT ANY SINGLE LOCATION THE EFFECT OF CHANGES IN
SPECIES RICHNESS MAY VARY FROM STRONG (E.G. PORTUGAL, SWITZERLAND) TO
UNDETECTABLE (E.G. GREECE), BUT ON AVERAGE WE WOULD EXPECT PRODUCTIVITY TO
DECLINE AS SPECIES RICHNESS DECLINES.
DEPARTMENT OF COMPUTER SCIENCE,
KARUNYA UNIVERSITY

10. PROCESSES TO EXPLAIN
RELATIONSHIPS BETWEEN DIVERSITY
AND ECOSYSTEM FUNCTION• ‘SAMPLING EFFECT’ OR ‘SELECTION PROBABILITY EFFECT’
• NICHE COMPLEMENTARITY
• POSITIVE SPECIES INTERACTIONS E.G. MUTUALISMS
DEPARTMENT OF COMPUTER SCIENCE,
KARUNYA UNIVERSITY

11. PROCESSES (CONTD)
THE SAMPLING EFFECT
• THE SAMPLING EFFECT:
• MORE DIVERSE COMMUNITIES HAVE A GREATER PROBABILITY OF CONTAINING AND
BECOMING DOMINATED BY, A HIGHLY PRODUCTIVE SPECIES.
• IMPORTANT BIOLOGICAL PROPERTY OF ECOLOGICAL SYSTEMS OR
• ARTEFACT OF SPECIES RICHNESS EXPERIMENTS AND RANDOM ASSEMBLAGES, A ‘HIDDEN
TREATMENT’
DEPARTMENT OF COMPUTER SCIENCE,
KARUNYA UNIVERSITY

12. FG 2
FG 3
FG 1
SP 1
SP 2
SP 3 SP 4
Niche complementarity: Within- and between- FG diversity
Ecological differences between species lead to more complete utilisation of
available resources in more diverse communities. Differences between species
of different functional groups are expected to be greater than differences
between species of the same FG
DEPARTMENT OF COMPUTER SCIENCE,
KARUNYA UNIVERSITY

13. Environmental fluctuation
6 spp 1 spp
7 spp 1 spp
Stable conditions
The insurance hypothesis: More diverse assemblages will have a greater
probability of having species that are adapted to changed conditions
Contribution
of each
species to
ecosystem
function
Species richness
DEPARTMENT OF COMPUTER SCIENCE,
KARUNYA UNIVERSITY

14. THE INSURANCE HYPOTHESIS: MORE
DIVERSE ASSEMBLAGES HAVE A GREATER PROBABILITY OF
CONTAINING SPECIES THAT ARE ADAPTED TO CHANGED CONDITIONS
DEPARTMENT OF COMPUTER SCIENCE,
KARUNYA UNIVERSITY
ecological
process
Constant conditions Variable conditions
1 sp.
2 sp.
4 sp.
10 sp.

15. END
DEPARTMENT OF COMPUTER SCIENCE,
KARUNYA UNIVERSITY