Geography 3412, Environmental Conservation: Ecosystems Management

Lecture Notes

Chap. 6: " Issues Regarding Populations and Species"

Biological concept: genetic differences, ability to breed.

Phylogenic concept: based on patterns of ancestry and shared derived characteristics.

Species identities are not immutable, and are debated among different philosophies. A big difference is between the "lumpers" and the "splitters": some experts lump similar populations into one species, and another split each population into separate species based on different characteristics. In Colorado this has played out on the Preble’s Meadow Jumping Mouse ands the Gunnison Sage Grouse.

Obviously the ecosystems manager can have a problem determining which notion of species to manage for, and the decision may have political and economic implicaitons.

Lumpers like the Populational view and splitters tend to adhere to the Typological view of species.

The "within-species" variation inherent in the populational view is very important to ecosystems management because it suggests that managers should not only seek to conserve species as defined but to conserve genotypical variety within formally-defined species. This variaiton within species is a biological resource that is often neglected in management.

Why recognize within-species variation?

1. Different populations of the same species may contain valuable genetic diversity

2. Different species may contain unique local adaptations useful in a the future if anthrpogenic or natural change occurs.

3. A population in an ecosystems probably plays a function in that ecosystem, so its loss is the loss of a ecological process, even if population(s) of the species exist elsewhere.

Categories with management implications:

Keystone: role and effect on ecosystem is large (larger than size or pop might suggest): keep the ecosystem functioning.

Indicator: a species whose population or condition reflect other environmental conditions, like presence or absence of pollution. Also used in management as species obligated to certain habitat or vegetation community (like riparian), thus indicates extent and quality of that habitat.

Umbrella: require conditions that also act as support other species, often linked to amount of area and habitat required for them to survive. Preserve enough habitat for the grizzly and you bring with it a large suite of other species without having to design other species-specific management plans.

Flagship or Charismatic: species that evoke support from humans (e.g., panda)

Vulnerable: species or pop susceptible to extinction. Usually due to: limited pop and range; habitat shrink; behaviors like poor dispersal or bad interactions with humans and human-dominated habitats.

Economically-Important: species harvested for economic gain; species that cause economic loss, species valuable for recreation and tourism.

Problems in categorizing species: is the prairie dog really vulnerable? And is it "keystone" to the Great Plains grassland ecology (e.g., by its role in soil, vegetation, and predator-prey processes)?

Spatial and Geographical Distributions

• Alpha richness: # species in a small areas of similar habitat (e.g., multiple stands of old growth spruce).

• Gamma richness: # of species in a region of multiple habitats;

• Beta richness: difference in species number among habitats in a region.

Answers have implications for designing conservation strategies across landscapes.