Maintaining Biodiversity

Pregunta	Respuesta
3 biggest threats to biodiversity	Loss/Alteration of Habitat, Introduction of Nonnative Species, Over-harvesting
Diversity	The number of different species, and variation within species
Diversity of plants vs animals	Lower plant diversity = lower herbivore diversity. Lower herbivore diversity = lower carnivore diversity.
Indirect effects of plant diversity	Different plant species have different impacts on abiotic factors. Shade, soil properties, etc.
Succession	The change in organisms living in an area over time, after a disturbance.
Primary vs Secondary Succession	Primary = from bare rock Secondary = soil and some survivors remain.
1st species to grow on bare rock. What do they do to pave the way for new species?	Lichens- symbioses of bacteria/algae and fungi. They start photosynthesis, and wear down rock so plants can take root after they decay.
Describe the timeline for different species to establish from pioneer to climax communities.	Pioneer: Bare rock, lichens, small annuals + lichens, Perennials + grasses. Intermediate: Grasses, shrubs, shade intolerant trees. Climax: Shade tolerant trees.
Early vs late colonizers:	Early: High dispersal, short lifespan, poor competitor. Late: Sometimes poorer dispersal, slower growing/longer lived, good competitors
Climax Community	System whereby current species are replaced by individuals of the same species.
Disturbance	An effect that sets the community to an earlier stage in succession.
Small Scale Disturbance	Could be small & localized (a tree falling, ect.) Allows survival and reproduction of shade intolerant species, which fill the hole in the canopy until a shade tolerant sapling outcompetes them..
Large Scale Disturbance	Sudden, and effects a large area (Fires, volcanic eruptions, hurricanes) Where these occur regularly, sometimes life evolves to survive, and even depend on them (Resinous cones of jack-pine need fire, etc.)
What advantage is gained by waiting until after a fire to release seeds and germinate?	Fewer competitors around after a fire.
Species diversity maintained by	Disturbance
Generally shade intolerant genera:	Salix (willow), Populus (aspen/poplar), Rubus (blackberry), Juglans (walnut), Carya (hickory), Prunus (cherry)
Generally shade tolerant genera:	Acer (Maple), Picea (Spruce), Thuja (Hemlock), Abies (Firs)
How is climate change impacting the range of certain species and systems?	The plants that can are retreating North, or to higher elevations. If higher elevations aren't available, they disappear.
Why are shifting ranges a problem?	The whole system doesn't shift with the species. They find themselves in new systems with different competitors, predators, etc, and could disrupt the system or quickly die off.
Importance of Germplasm	Collection of genetic material of native species is important for conservation in the locale.
When buying seeds, buy local and avoid Cultivars, varieties, and "Nativars". Why?	Most have undergone artificial selection for traits preferred by horticulturists.
What benefit does a plant get by waiting through a cold period to germinate?	More favorable conditions for growing.
Which section of oaks germinate in fall, and which would you stratify (preserve) to start in spring?	Stratify the Lobatae (Red oaks), they germinate in spring. Quercus (White oaks) germinate in fall. Plant as soon as they're ripe.

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	Creado por Wes Smalley hace casi 6 años