* Critical Findings
Settlement in the Sierra
* Deforestation in the Mid-1800s
Resource Use: Changing Needs Through Time
Regional Economies
* Social and Economic Analysis
Community Well-Being in the Sierra
MANAGEMENT SCENARIOS AND STRATEGIES
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Management Scenarios and Strategies
We begin this section with a scenario of future population growth and distribution
in the Sierra. This analysis shows that if growth and development continue as they
have to date, significant impacts to Sierra Nevada resources and a reduction of social
and economic well-being are likely. We conclude the section with a strategy that outlines
a general approach to improving community well-being by directly linking ecosystem
management activities to Sierra Nevada communities.
Future Population Growth and Settlement
The Sierra Nevada is likely to undergo significant land conversion through continuing
population growth over the next half century. The total land area converted to human
settlement to accommodate 19902040 growth will depend upon the spatial pattern and
average density of settlement, which will in turn depend upon the complex interaction
of public policy, infrastructure, and land economics. Strict development controls,
significant expansion of water and sewer systems and higher land prices would be
likely to lead to a more intensive pattern of development with less land conversion than would
occur otherwise. Continuing the existing patterns of development would consume more
land than could be achieved under these conditions.
Current population growth and economic activity in the Sierra Nevada are increasingly
dominated by the amenity values of resources and the environment for commuters, retirees,
and people working in the recreation and tourism sectors. The impacts of future growth will therefore affect the social and economic well-being of the Sierra Nevada
as well as its ecosystems. Public policies designed to manage growth will need to
encourage patterns of development that reduce the impacts of human settlement.
Land conversion due to human settlement can have a wide range of indirect effects
on ecological structure and function. The most important of these in the Sierra Nevada
is associated with impacts on the fire regime in both settled areas and adjacent
wildlands. Human settlement affects the structure and level of fuel load, viability of presuppression
fuel-management strategies, ignition risk, availability of suppression resources,
and the manner in which suppression efforts are allocated and deployed (e.g., to protect structures rather than wildlands). Each of these will in turn affect the
future risk and characteristics of fire in the Sierra Nevada. Vegetation management
in the urban forest of areas converted to human settlement can either decrease or
increase fuels in the urban-wildland intermix zone. Without additional research on the relationship
between alternative patterns of human settlement and specific ecological impacts,
it is difficult to forecast ecological implications of continuing existing patterns of development and using a range of alternative growth management policy mechanisms
for mitigating those impacts.
General relationships can still be inferred, however, based on theoretical and empirical
research to date. In particular, land conversion causes at least five direct effects
on vegetation and wildlife:
- Reduced total habitat area through direct habitat conversion
- Reduced habitat patch size and increased habitat fragmentation
- Isolation of habitat patches by roads, structures, and fences
- Harassment of wildlife by domestic dogs and cats
- Biological pollution from genes of non-native plant species
In addition to these direct effects upon vegetative composition, structure, and function
(which in turn affect wildlife habitat and wildlife viability), land conversion for
human settlement has several direct effects on hydrologic regimes that could be important:
- Increased impervious surface and increased peak runoff
- Increased heavy metal and oil runoff from impervious surfaces
- Increased risk of ground-water and/or surface water contamination through septic effluent disposal
- Decreased ground-water flow to surface water system due to ground-water pumping
- Modified surface water flow due to irrigation, septic system effluent disposal, and treated wastewater discharges
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