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2-‐6-‐3: Land Use and Management
A"er this lecture, you should be able to: Iden6fy and assess value of land-‐based resources.
Explain the difference between how private and public lands (commons) are used.
Differen6ate between conserva6on, preserva6on, and restora6on.
Evaluate the factors that determine maximum sustainable yield and predict outcomes for these various condi6ons.
Ecosystem capital
Biomes: reflect organism responses to clima6c condi6ons
Terrestrial biomes: forests and woodlands, grasslands and savannas, croplands, wetlands, desert lands, and tundra
Oceanic ecosystems: coastal ocean and bays, coral reefs, open ocean
Human economy and well-‐being directly depend on exploita6on of natural goods (provisioning services) Ecosystems provide all food, fuel, wood, fibers, etc.
Natural services (regula6ng and cultural services) process energy and circulate maKer
Private vs. public lands
Natural ecosystems are maintained when they provide the greatest economic (direct-‐use) value for their owners
Corporate-‐owned Maine forests are used for lumber and paper Land sold to developers would become house lots
Some ecosystems are publically owned (state, federal lands) or cannot be owned (oceans) They are s6ll exploited
Sustainable exploita6on maintains natural services Ecosystems can also be restored
Conservation, preservation, restoration
Renewable resource: ecosystem’s and biota’s ability to regenerate Ecosystems can replenish themselves They are sustainable
Conserva5on of biota and ecosystem manages or regulates use so it does not exceed the capacity of the species or system to renew itself Has a well-‐defined goal
Its goal is to ensure species and ecosystem con6nuity regardless of their poten6al u6lity May preclude making use of the species or ecosystem
Old-‐growth (virgin) forests must be preserved (not cut) Second-‐growth forests can be conserved (cut sustainably)
Conserva6on and preserva6on can conflict Endangered Muriqui monkeys of Brazil need second-‐growth forests Conserva6on of forests is essen6al for preserva6on of this monkey
Patterns of human use of natural ecosystems
Consump6ve Use People harvest natural resources for
food, shelter, tools, fuel, clothing Not in a country’s calculated
market economy People barter or sell goods to
meet their own needs This “wild income” is important to
the world’s poor Bush meat: wild game in Africa that
provides protein Largely unregulated and involves
poaching Contributes to the decline of 30
endangered species Commercially killed primate meat
is found in New York, London, Paris, etc.
Produc6ve Use The exploita6on of ecosystem
resources for economic gain Products are harvested and sold An important source of revenue
and employment
For example, commercial trade in wood products generated $468 billion in 2006 Employing 13.7 million people
Wild animals and plants provide ini6al breeding stock Sources of genes for crop plants
or animals Sources of new medicines
Consumptive use
The four types of tenure
Consump6ve and produc6ve uses of natural ecosystem resources are the consequences of the rights of tenure (property rights) over land and water
Private ownership: restricts access to natural resources Commercial ownership: permits use of natural resources by
members of the community State ownership: implies regulated use
Open access: resources can be used by anyone Each has the poten6al for abuse or stewardship
Maximum sustainable yield The central ques6on in managing a renewable resource:
How much con6nual use can be sustained without undercueng the ability for renewal?
Maximum sustainable yield (MSY): the highest possible rate of use the system can match with its own rate of replacement or maintenance MSY applies to harves6ng biota, air/water quality, soils Used in 6mber cueng, fishing, park visita6on, pollu6on
MSY is just before the point at which use begins to destroy the system’s regenera6ve capacity
Carrying capacity of an ecosystem: the maximum popula6on the ecosystem can sustainably support
A popula6on below carrying capacity grows This yield can be harvested
In a popula6on approaching carrying capacity, compe66on between individuals reduces recruitment
In a popula6on near or at carrying capacity, thinning reduces compe66on and obtains op6mal growth
MSY is not obtained with a popula6on at the carrying capacity
Obtaining MSY is difficult
The op5mal popula5on for harves6ng at MSY is halfway to the carrying capacity
Using MSY is complicated Carrying capacity and op6mal popula6on vary
Replacement of harvested individuals varies
Humans adversely affect habitats, carrying capacity, sustainable yields, etc.
Accurate es6mates must be made Data on popula6on size and recruitment rates are o"en hard to
obtain
Subsistence agriculture Subsistence farming: developing world farmers
use labor-‐intensive tradi6onal agricultural methods Prac6ced on marginal land Described as the “silent giant” that feeds most
of the world’s poor Subsistence farmers live on small plots of land
They raise food for their household They may sell a small cash crop They do not consider themselves poor
Subsistence farming is prac6ced in regions with rapid popula6on growth But is best suited for low popula6on densi6es
67% of people in sub-‐Saharan Africa depend on agriculture for their livelihood They experience low yields, rapid popula6on
growth, poverty, hunger, and high child mortality
The World Bank’s World Development Report 2008 states that agriculture carries the poten6al for li"ing rural Africa out of poverty
But most rural farmers lack fer6lizer and seeds to improve yields Government subsidies in Malawi have doubled
yields
Using the commons A common-‐pool resource: owned
by many people Or by no one (open access)
Commons: a system with open access Use by one does not subtract
from use by others Examples: knowledge, federal
grasslands, fisheries, groundwater, atmosphere, some forests
Exploita6on of the commons causes serious problems Tragedy of the commons: ruin
of the resource Sustainability: maintaining
common-‐pool resources to yield benefits for present and future users
Original commons: pastures used by anyone to graze caKle Whoever grazed the most caKle
benefited the most Those who reduced their caKle
suffered lost profits The commons were overgrazed
Problems arise With open access to a common-‐
pool resource But with no (or an ineffec6ve)
regula6ng authority Along with no func6oning
community Then profit becomes the only
mo6ve in exploi6ng a resource This tragedy can be avoided only
by limi6ng access
Limiting freedom
Private ownership can mi6gate the tragedy of the commons Restricts access to a renewable natural resource It should be exploited to guarantee con6nued harvest But this theory does not work when an owner maximizes
immediate profit (e.g., corpora6ons)
Regula6ng access to a commons allows for Protec6on for sustained benefits Fairness in access Mutual consent of the regulated Best if locally controlled by those who benefit most
Public policies
To achieve objec6ves of conserva6on when harves6ng living resources Consider the concepts and limita6ons of MSY
Consider the social and economic factors causing overuse and degrada6on
Establish and enforce protec6ve public policies Natural resources can be sustainably used
Some6mes exploita6on and degrada6on have gone too far Restora6on ecology: restora6on of damaged ecosystems
Ecosystem restoration
Restora6on ecology repairs damaged lands and waters Returning ecosystem
integrity, resilience, produc6vity
A worldwide, $70 billion industry
A thorough knowledge of ecosystem and species ecology is essen6al to successful restora6on efforts
Ecological problems that can be solved include Soil erosion, strip mining,
wetland draining, hurricane damage, agricultural use, deforesta6on, overgrazing
End-‐of-‐Lecture Objectives
Iden6fy and assess value of land-‐based resources.
Explain the difference between how private and public lands (commons) are used.
Differen6ate between conserva6on, preserva6on, and restora6on.
Evaluate the factors that determine maximum sustainable yield and predict outcomes for these various condi6ons.
