Lecture 7: Hyperdiversity

Question 1

simplest measure of species diversity/biodiversity:

Answer 1

species numbers

Question 2

tropical forests are ___diverse

Answer 2

hyperdiverse

Question 3

-rainforests are estimated to be home to__ % of all terrestrial species, despite covering __% of surface

Answer 3

50

<2

Question 4

can be __ specie sin just 5 ha of forest

Answer 4

500+

Question 5

AMAZON hyper diversity: estimated to be ___ trees

Answer 5

3.9X10^11

Question 6

AMAZON hyper diversity: ___ tree species

Answer 6

~16 000

Question 7

AMAZON hyper diversity: __ ‘hyperdominant’ tree species

Answer 7

227 –> represent ~50% of all trees

Question 8

worlds most abundant tree

Answer 8

Euterpe precatoria 5.21 X10^9

second Protium altissimum 5.21X10^9

Question 9

native tree diversity in the amazon is __X higher than in the GB & Ireland

Answer 9

30 times

Question 10

Tropical forests are not the only hyper diverse systems, some other examples:

Answer 10

• coral reefs
• desert plants
• phytoplankton
• sewage

Question 11

diversity relates to the number of

Answer 11

species in a given environment

Question 12

current concepts of diversity are more complex than just the number of species present in a place, takes into consideration:

Answer 12

• species diversity
• functional diversity
• phylogenetic diversity

Question 13

species diversity and tropical forests:

Answer 13

they are exceptional,

Question 14

functional diversity is underpinned by

Answer 14

species and phylogenetic diversity

Question 15

functional diversity:

Answer 15

refers to those components of biodiversity that influence how an ecosystem functions

Question 16

key outcomes of functional diversity in tropical forests are:

Answer 16

• Productivity: tropical forests are the most productive ecosystems
• Carbon Storage: CS in tropical forests is a direct function of productivity

Question 17

the relationship between FD and biodiversity has been ________: however …

Answer 17

controversial

however, usually positive and tropical forests are important with respect to all of these

Question 18

zhang et al 2012 looked at

Answer 18

the drivers of productivity using a global survey of 54 sites

Question 19

Cauvanaugh et al 2014 looked at

Answer 19

the relationship between carbon storage, environment and diversity

Question 20

not only are forests significant carbon ___, but also this has been increasing:

Answer 20

diversity? amazon Above Ground Biomass has increased

–> reasons for increase include CO2 enrichment and successional changes

Question 21

problem of diversity: Competitive exclusion:

Answer 21

• species that are similar to each other consume similar resources. hence compete with each other
• more similar species compete more strongly
• species that are too similar cannot coexist and one competitor is expected to outcompete the other

Question 22

problem of diversity: limiting similarity

Answer 22

• competitive exclusion means that species that are too similar cannot coexist
• consequently there are limits to the similarity of species within ecological communities
• essentially room for one one species per niche

Question 23

problems of diversity: not enough niches

Answer 23

• competitive exclusion and limiting similarity suggest that we need a niche for each species in a community
• BUT in hyper diverse communities there simply can’t be enough niches
• very limited set of required resources N,P,K water, light

Question 24

ways in which species can divide niches: GAP DYNAMICS

Answer 24

• species may be adapted to exploit different stages of succession from gap opening to closing
• this generates diversity in species number and ecological strategies

Question 25

theories of diversity:

Answer 25

large number of theories proposed to explain diversity and coexistence

• most theories are ecological (how spp co exist)
• some evolutionary (why do we have so many)
• • difficult to evaluate

Question 26

theories of diversity: 2 types

Answer 26

equilibrium & non-equilibrium

Question 27

equilibrium theory:

Answer 27

balance between losses and gains to communities, such that overall species richness is maintained as a constant

• implies processes that balance diversity e.g. if species become rare then they should increase
• mathematically difficult

Question 28

non-equilibrium theory:

Answer 28

disturbance (hurricane,fire etc) / stochastic (random) events prevent equilibrium being reached
-hence competitive exclusion DELAYED

Question 29

intermediate disturbance hypothesis:

Answer 29

relationship between spp. diversity and level of distribution (normal distribution)

Question 30

evidence that disturbance and diversity are related:

Answer 30

• However disturbance only slows deterministic extinction
• unless something else is going on
• e.g. adaptation to different environments
• trade-offs between competition and dispersal
• Adaptation to gap dynamics fits with evidence that disturbance promotes diversity.

Question 31

age of tropical forests:

Answer 31

• evidence of amazon rainforest in SA dating back to at least the late Cretaceous-Eocene
• evidence rainforest have withstood severe environmental disturbance (e.g. glaciation)
• age and robustness should promote diversity