Lecture 10 Flashcards
define disturbance:
a disturbance is an relatively discrete event in time that disrupts ecosystem, community, or population structure and changes resources, substrate availability or the physical environment
disturbances are key processes for sustaining what?
species, communities, ecosystems and landscapes
what is abiotic disturbances?
- wind 2. flood 3. fire
What are the limitations or criticisms of NV, NDR and HRV
- role of humans in reference systems: the disturbance first natives and use cause to the landscape. Not always possible or goo to return land to what it was to 1000 years ago. 2. Amount of data avilable. 3. Will this be relevant for future condtions?
what kind of models are used during non equilibrium paradigms?
state and transition models to account for this vairability.
what role did the first nations people play in north america?
Had a role in setting fires and the rise of agriculture.
what is an example of humans altering important processes?
- landscape tranformation which altered the natural fire regime by dissecting the prairies.
what are biotic disturbances?
- insects 2. disease 3. animal damage
why is approximating past conditions important?
offers one of the best means for predicting and reducing negative impacts on ecosystems
equilibrium paradigm:
ecosystems have the capacity for internal regulation through balancing an self-regulating feedback mechaisms, giving rise to predictable and directional responses after disturbance.
wolf cull is only a short term plan for woodland caribou. what should be the long term plan?
regenerating and reclaiming forests and providing protected areas!
what does natural varaibility mean?
even when places are not influenced by people there is huge variation in the landscape.
spatial and temporal variation in ecological conditions that are unaffected by people
what does histroical range of variation mean?
the variation of ecological characteristics and processes over a scale of time and space that are appropriate for a given management application.
what does the non equilibrium paradigm mean?
predits that ecosystems are more dynamic and less predictable after disturance than equilibrium systems
how do humans reduce spatial and temporal variability?
- reduces biological diversity 2. decreases resistance to disturbance, increases vulnerability to other forces. 3. decreases resiliency after disturbances 4. reduces sustainability.
How can disturbance both create and respond to landscape pattern?
fires create and respond to landscape grazing. Areas that have just been burnt creates grasses that are more pallitable which will be grazed.
what is an excellent example of predator prey relationships?
how the wolf changes the rivers.
severity:
related to intensity, effect of the disturbance on the community of ecosystem
whats types of variation can you expect to occur naturally on the landscape? 6
- patchy distribution of resources 2. predator prey relationships 3. weather related ike droughts and floods. 4. insect, pest and disease outbreaks 5. fire 6. tree falls
- grazing burrowing and wallowing
what does disturbance create?
heterogenity–> many vegetation patches on the landscape at different stages of succession
what is an example of an animal that has a variety of habitats and therefore needs connectivity between those habitats.
woodland caribou! They need different places to forage and a variety of places for refuge!
why werewolves able to get to the caribou?
we were creating corrdiors for the wolves to get to caribou easier.
ecosystems are assumed to return to their ———— state after disturbance.
pre-disturbance
size:
size of the disturbed area.
