Lecture 1 Flashcards
what is the tropics?
an area between the tropic of cancer (23.4 degrees north) and the tropic of capricorn (23.4 degrees south)
what can the tropics also be know as?
equitorial zone
what is a temperate climate like?
follows a cycle and is very varied
what is a tropical climate like?
more rain, higher temps, less cycle (stable temps)
how much rainfall does a rainforest have per year?
over 2m
what does a hot and wet climate result in?
wetter and drier seasons
describe the structure a tropical forest?
tall
dense
dark under canopy (reached by 1-2% sunlight)
there are lots of different types of tropical forests what are 4 big differences?
1) continental variation e.g. the amazon, the congo
2) hydrology e.g. within the amazon there is areas of dry (terra firme) and flooding (varzea)
3) altitude e.g. Andes subtropical cloud forest
4) rainfall e.g. can get dry forests (Tumbesian dry forest)
why are tropical forests important ? (5 points)
1) most species on Earth
2) enigmatic wildlife (difficult to understand)
3) most endemic species
4) highest densities of species on Earth (hyperdiversity)
5) typified by complex networks of interactions
describe hyperdiversity in the tropics?
1 hectare can have 650 tree species - massive number of species per area
5 examples of network interactions within tropical forests
1) predation (large predators exert top down effects on smaller predators
2) nutrient cycling
3) plant pollination by insects, birds and bats
4) seed dispersal by birds and mammals
5) symbiotic relationships where species live together and trade benefits
why do tropical forests matter?
they provide key ecosystem services ‘the provision of a natural resource or process that is valued by humankind’
examples of key ecosystem services
carbon storage, wood fruits and animal protein, hydrological services ( rainfall and temp control, erosion and flood protection)
what is the global biodiversity crisis?
man is causing the 6th mass extinction - biodivrsity loss is most severe in rainforests
what activities are causing most species loss?
habitat loss and degradation and overexploitation
e.g. farming and fragmentation, logging and hunting
what are devils gardens?
a large stand of trees dominated by one or two ant plant species
whats the relationship between ants and ant plants?
Duroia hirusta plants provide M. Shumanni ants with housing in domatia - can be very large with millions of ants - colonies can survive for 800 years
what are domatia?
structures produced by plants for ants to use - small chambers in the plant that provide shelter - intended for symbiotic relationships
what is the local legend to explain devils gardens
known as spirit clearings - invisible villages of spirits- swollen trunks caused by fires set
what is the actual cause of swollen trunks in devils gardens?
inhabited by the workers, brood and queens
what is the benefit gained for the trees
the workers kill other understorey plants by injecting them with formic acid - creates clearing for host plant to survive
