Flashcards
session 8
Flashcards do conjunto (89)
- 1What is habitat fragmentation?the break up of large habitat into several separate, smaller remnants, for example because of land use change’.
'Habitat fragmentation is technically a separate process from habitat loss, - 2Why is it important to have at least one habitat loss for habitat fragmentation to take place?however it is very difficult for habitat fragmentation to take place without there been at least some habitat loss as well, this is an important fact to keep in mind.
- 3What has now expanded in the expense of the Amazon rain forest?Tropical Forest fragmentation is what comes to mind when people talk about fragmentation. Fragments of forest in the agricultural landscape around sinop, Brazil, an area where soybean farming and cattle ranching have expanded at the expense of the Amazon rainforest
- 4What is the obvious cause of fragmentation in the UK?An obvious cause is roads but also rail and canals break up the landscape fragments can be forest fragments separated by farm land or urban areas
- 5What are farms and hay meadows separated by?Also, fragmentation with the farm, hay meadow separated by arable land
- 6What are the traditional farming practices surrounded by?Traditional farming practices (e.g. Crofts in Scotland), surrounded by intensive farming practices, Corn Crake found only in traditional less intensively managed upland areas separated by different grazing or management practices.
- 7What has happened to Dorset heathland between 1759 to 1987?Dorset heathland from 1759 to 1987, has reduced the hectors of available land.
- 8What are the three things that different species will respond to within the same fragmentation?• Habitat vs non-habitat
• Traversable distances
• Dangers - 9What is an example of a habitat vs a non-habitat?• Habitat Vs Non-habitat: for a species that lives in the grey habitat this area much is less fragmented that one that lives in the green habitats. E.g, deer compared to a bear, generalists vs specialists.
- 10What is the traversable distance?• Traversable Distance: a distance of 1km between patches is connected for a bird that can fly 10 km but isolated for a butterfly that can only fly 250m.
- 11What are the travel dangers?• Travel danger: this may come form predators or human interactions. For example, if these green patches were isolated by human settlements and farms, a squirrel may be at less risk while travelling through the non- habitat than a tiger would.
- 12What is the relation between fragments and islands?- Fragments can be thought of as islands (patches) of suitable habitat in a sea (matrix) of unsuitable habitat.
- Some of the theories that apply to islands will also apply to habitat fragments. - 13What will fragment as islands feature more of?Fragments as islands will feature more in meta populations in the second half.
- 14What happened in Lago Guri, Venezuela 1986?You can see the literal fragments functioning as islands. When the Lago Guri dam was constructed they flooded large sections of forest.
- 15What where the persistent species that were all hyperabundant?howler monkeys, tortoises and leaf cutter ants.
- 16Why were there no predators on the Lago Guri islands?– likely because the small size of the islands did not provide enough area for hoe range for them (predators generally have a larger range than herbivores. Hyperabundant species are herbivores or ground dwelling – and they became hyperabundant because there was reduced competition or no predicators (nothing eating them)).
- 17What happened to the understorey of dry forest on large island at Lago Guri?The hyperabundant species have decimated the understory of the forest.
- 18When did the drought begin on Lago Guri?A drought began in 2001
- 19When where extreme levels of drought reached in Lago Guri?reached extreme levels in 2003.
- 20By 2003 how much had the water levels dropped?By 2003, the lake level had dropped 26 meters,
- 21How many islands where surrounded by water in 2003?only three of the islands were left surrounded by water
- 22What did the drought of the Lago Guri islands help do?That allowed the animals to redistribute and the overcrowded populations of herbivores simply dispersed.
predators could also gain access – during 2003 six different predators were founds on islands that previously had none.
Basically, the predators moved onto the formally isolated islands, saw the hyper abundant herbivores and ate them. - 23In relation to core and edge what happened to the environmental conditions between middle patch and edge?- Environmental conditions vary between the middle (core) of a patch and the edge.
- The edge effect is the changes in population or community structure that occurs at the boundary of two habitats. - 24In relation to core and edge what is the edge effect?What is core and edge Is dependent on the species, it can be 10m or km.
- 25What are examples of edge effects?sunlight penetration
-Changes in humidity (both can cause changes in the plant community with knock on effects for the rest of the community/ food chain)
- increased predation/ parasitism (studies have shown bird nest closer to the edge of a patch are more likely to lose eggs/ chicks to predators who can more easily penetrate the edges of the forest than the core).
- Increased anthropogenic disturbance (noise, pollution, litter) - 26In relation to edge effect what does fragmentation lead to?Fragmentation will lead to an increase in edge habitat and those species which require it while there is a decrease the interior habitat and the species that live there.
- 27What happens to the species on the edges as fragmentation occurs?Important point forms a conservation point of view it that it is typically the species which live in the interior habitat which are endangered.
edge effects increase over time, loss of forest architecture. - 28What did the Greater Mekong Region of Southern eastern Asia use to measure forest fragmentation between 1973 and 2009?- Core forest
- Patch forest
- Transition forest
- Edge
- Perforation - 29What does a core forest have?interior continuous forest
- 30What does a patch forest show?– patches that are displaced from core
- 31What position is a transition forest in?between patch and core
- 32Where is the edge forest?forest bordering non – forest
- 33Where is the preformation forest?– hole of non – forest inside forest
- 34What has happened to core forests over the years?Although there would appear to still be a lot of forest present it is clear that very little is core forest compared to 40 years earlier
- 35What is the edge effect?The edge effect is species specific. Of these sic beetles A, E and F are forest specialists while B is an open specialist and C and D are edge specialists.
- 36What are the examples of natural fragmentation or patchy habitats?Hay meadows
Reed beds
Mountain tops - 37What is the term used for a large continuous habitat?the term for this is heterogeneity (a heterogeneous environment/ habitat) for comparison a monoculture would be homogeneous
- 38Where is an area where there is an example of natural heterogeneity Vs Anthropogenic fragmentation?a road compared to a forest fire
- 39What are anthropogenic threats?Anthropogenic threats to organisms they haven’t evolved to deal with (if they couldn’t cope with the natural hetero they’d be extinct already)
- 40What are the natural (in mature landscape) threats?Natural (in mature landscapes) have fewer patch to edge contracts, which reduced edge effect (forest to scrubland to meadows compared to forest to carpark).
- 41What do Anthro trends tend to be?Anthro tends to be on going and accumulative
- A fire goes through and the landscape recovers
- A road is a permanent chance, and leads to pollution, noise litter, possible additional buildings, car parks, houses and more roads. - 42What is the problem with fragmentation?- Lower native biodiversity
- Increase in invasive/ non-native species
- Decrease in native biomass/ productivity
- Decrease in ecological functionality
Just thinking about anthropogenic fragmentation these are from an ecosystem level. - 43What do road cause in relation to fragmentation?Roads lead to road kill – everything from deer to hedgehogs, frogs, newts. Not sure a problem in the western world – I’ve seen it in Serengeti national park.
- 44Why may animals be hunted if there is an increase in roads?Increase in roads also leads to increase human penetration into formerly wilderness areas, which can increase levels of disturbance (edge effects) and also increase hunting pressures in places where this occurs as hunters can access formally inaccessible or difficult access areas.
- 45What is the importance of the Thylacine?This negative interaction with humans has already been credited with at least one extinction: the Thylacine was, at the time of European arrival in the area, confined to Tasmania of stock killing were attributed to it, probably rightly so, a bounty was places on it. The bounty varied over time but was sometimes as much as £1 for an adult (equal to around £130 today), it is believed the species went extinct in the 1930’s or40’s (last captive individual died in 1936).
- 46Due to stochastic events what has increased?Randomly occurring natural events such as fire, flooding or insect population explosions
- 47What has the increase in fragmentation caused?As an example: panda diet consists entirely of bamboo, certain species of bamboo flower and then die back. Historically this wasn’t a problem, panda could move to other areas and there are other bamboo species that flower at different times and some species which dot flower at all. In the present situation pandas’ historic range is highly reduced and fragmented, results in some areas with only one or two stochastic events, and potentially fatal for pandas living in that particular habitat fragment.
- 48Fragmentation reduces genetics in what way?- Reduction or absence of movement between fragments means results in a reduction of gene flow.- Reduced mate choice
- Inbreeding
- Reduced genetic diversity in a population - 49What is inbreeding?the production of offspring closely related individuals
- 50what does the reduced genetic diversity result in?physical deformities
reduced fecundity (reduced number of off spring)
failure to breed at all
plant only - 51what is an example of physical deformities?Florida panther, also lack of diversity at the usually highly polymorphic MHC is partly responsible for the rapid spread of Devil facial Tumour disease in Tasmanian Devils
- 52What is an example of failure to breed at all?no confirmed cases in animals, possibly part of the problem of the northern white rhino
- 53What is the problem with plant loss?loss of diversity at self-incompatibility loci results in the failure of fertilisation, even when pollen is from a different plant it is recognised as self and fertilisation isn’t possible. Illinois Lakeside Daisy (subspecies), almost went extinct because the last three members couldn’t breed with each other (survived when it was out crossed to the Ohio subspecies).
- 54What are the examples of ways some small fragments lose species?- Providing insufficient range size
- Reduced resources supporting smaller populations
- Community changes following loss of predators
- Absence of specialist resources (Inc. symbiotic partners)
- Change of environmental conditions (edge effect)
- Fragment sizes is simple too small, an animal that needs a home range of 10km will no survive on a fragment that is only 5km
- Small population – vulnerable to stochastic events and inbreeding
- A predatory species that kept a herbivore in check is absent, herbivore becomes hyper abundant and out competes other species.
- Edge effect, a species which needs to be at least a km from the edge of a forest will not be found in a fragments that is less than 2km wide. - 55What is the definition of metapopulations?“A set of particularly isolated populations that belong to the same species, between which individuals can freely migrate.”
- 56In relation to terminology what is the metapopulation translation for population?metapopulation
- 57In relation to terminology what is the metapopulation translation for a sub population?population
- 58What should each population in a metapopulation have?Each population in a metapopulation must have a non-trivial risk of extinction ie it is reasonably possible that it will go extinct in the normal course of events.
- 59What happens after an extinction event on a patch?After an extinction event a patch is recolonized by individuals from other local populations.
- 60Can metapopulations patches that go extinct be recognised?Between patches of suitable habitat surrounded by a matrix of unsuitable habitat. Mortality risk is generally higher in the matrix than the patch, limiting movement between local populations.
The important thing to remember in metapopulations is that patches which go extinct can be recognised, it is this pattern of extinction and recolonization which denotes a metapopulation. - 61What are the stages of dispersal?- Pre-fertilisation
- pollen, eggs, etc.
- Post fertilisation
- seeds, larvae, etc.
- Adults
- forced by natural catastrophe
- mate searching (may result in gender specific dispersal) - 62What is an example of pre-fertilisation?pollen, eggs, etc.
- 63What is an example of post fertilisation?seeds, larvae, etc.
- 64What is an example of adults?forced by natural catastrophe
- mate searching (may result in gender specific dispersal) - 65What is the rate of mortality like between patches of suitable habitat surrounded by a matrix of unsuitable habitat?Mortality risk is generally higher in the matrix than the patch, limiting movement between local populations
- 66What do some species have when occupancy of a patch depends on the size and isolation of a patch?Looking at real landscape, imagine a species that lives in open fields, you have multiple patches dotted across the landscape with movement between the patches.
- 67Is the size and location species specific?yes
- 68What do patches of larger size tend to be?Patches of larger size can be more isolated.
- 69What do larger patches have a greater chance of?Less risk of extinction from stochastic events in larger patches.
Larger patches have a greater chance of been found by a random dispersing individual simply because they take up more geographical space. - 70What are the types of metapopulations?- Classical
- Core satalite (mainland – island)
- source sink
- Patchy population
- Non-equilibrium - 71What is a classic metapopulation?- a network of patches with an equal likelihood of extinction and recolonization.
- higher levels of interaction between individual within a patch than between patches
- all patch size are relatively small - 72What are the species that is found in a classic metapopulation?Marsh Fritillary butterfly (Euphydryas aurinia) in Britian
- 73What are the points thye marsh fritillary butterfly makes?- found in wet grassland habitat, larvae feed on devils bit scabious.
- Females may lay multiple clutches but the first is usually laid in the natal patch.
- If conditions are optimal additional clutches be laid in other suitable patches. - 74What is a core satellite population?- Mainland-island/ source sink
- Satellite populations have a greater probability of extinction than core populations
- Without emigrants leaving source populations, sink populations would decrease to extinction. - 75What is the species that is found in a core satellite population?Mountain lions (puma concolorin) the Nevada
- 76What have mountain lions helped to identify?- Andreasen et al. 2012
- Identified source sink metapopulation dynamics using microsatellite data to measure gene flow between populations. - 77What may a source sink dynamic be caused by?They suggest that this source sink dynamic maybe due to anthropogenic rathe than habitat quality
- 78What is a patchy population?- Local populations exists in habitat patches with high dispersal between patches.
- Effectively a single population within which individual are found in discrete groups.
- Most researchers do not consider this a true metapopulation - 79What are the species found in a patchy population?Reed bunting (Emberiza schoeniclus) in Switzerland
- 80What was discovered by the reed bunting?- Mayer et al 2009
- Species found in discrete subpopulations
- Study found high levels of connectivity between subpopulations and no risk of extinction.
- Concluded this is not a metapopulation and should not be managed as such - 81What causes a non-equilibrium population?- Local extinctions greatly exceed recolonization
- Vacant patches rarely or never recolonize
- Not a functioning/ stable metapopulation
- Frequently considered to be the result of anthropogenic influences - 82What can lead to a non equilibrium be cused by?Further fragmentation of a natural metapopulation can lead to this.
Can be hard to find case studies as there can be a lag time between the habitat fragmentation and the effects on metapopulations especially for species that have a long turn over (generation) time. - 83What species is an example of non equilibrium population?Samango monkey (Cercopithecus mitis labiatus) in South Africa
- 84What is the name of several types of metapopulations to form?Corridor creation
Planning reintroductions
Global zoo populations
Population management - 85How can the metapopulation be used in conservation?Habitat restoration planning
- 86What is corridor creationallow dispersal between patches, restore metapopulations which are fragmented beyond dispersal range. Can be used to encourage dispersal to one particular patch or direction, possible away from human contact (e.g. away from major roads)
- 87What is an example of planning reintroductions?marsh fits in Cumbria
- 88What are kept as metapopulations?Global zoo populations, especially captive breeding programmes, are managed as a metapopulation
- 89What is population management?moving animals or groups between reserves or fragments when they cannot naturally disperse – African wild dogs in South Africa – move related same sec grogs (i.e. sisters or brother) between reserves when needed, mimics natural dispersal
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- FlashCards sobre session 8 , criado por Abby Bettridge em 01-05-2019.
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