con bio final

Biome Crisis:

  • 21.8% of all Earth’s land area has been converted to human use

  • habitat conversion exceeds habitat protection by 10:1 in >140 ecoregions

  • grassland, shrubland, and savannas exhibit the greatest disparity between rates of habitat lost to protected area

Biological Responses to Habitat Fragmentation

  • Initial Exclusion – loss of species given remaining fragments represent only a sample of the original habitats

  • Isolation – Modified landscape restricts movement & dispersal

  • Island-Area Effects – Fragments include fewer habitats with smaller populations more susceptible to local extinction events

  • Edge Effects – Climatic influence and environmental degradation results in increased predation and competitors, reduced area of suitable core habitat

Critical Concept: Edge

  • Ecotone- natural transition zone between vegetation types.

    • important features that contributes to structuring landscape patterns

    • fragmentation introduces “artificial” edges and disrupts ecotones.

  • Impacts to patch:

    • temperature

    • light

    • humidity

    • wind

    • predation

    • exotic species

    • parasitism

    • disease

Types of Fragmentation

  • Perforation

  • dissection

  • fragmentation

  • shrinkage

  • attrition

    • all fragmentation is NOT equal

Perforation- creation of non-habitat within a matrix of continuous habitat

Dissection- linear segmentation of habitat matrix

Fragmentation- breakup of habitat matrix into multiple patches of unequal size

  • sometimes may result in “habitat shredding” effect

Shrinkage- reduction in size of the remaining patches in a landscape

Attrition- elimination of remaining patches in a fragmented landscape

Designing Reserves

  • SLOSS debate

    • single large or several small

  • Oversimplifies available choices

  • Depends on how much land you are trying to optimize (e.g. 10,000 acres vs. 100,000 acres)

  • Advantages of large reserves:

    • Contiguous areas- preserve intact communities of interdependent species

    • Contiguous areas- maintain viable populations of species that require large areas (e.g. large vertebrates)

  • Advantages of small reserves:

    • may preserve a broader range of species

    • protect small species with limited spatial needs

    • habitat refugia (e.g. urban areas, migratory birds)

  • SLOSS debate viewed as bifurcation in opinion. those advocating single large reserves classified as preservationists and those advocating several small reserves as conservations

    • reserve networks as middle ground where there is an intermixing of large and small reserves

Influence of Island Biogeography Theory

Non-equilibrium paradigm lessons for reserve design:

  • conservation units are not viable as isolated reserves

  • reserves will not maintain themselves in a stable and balanced configuration

  • reserves incur continuous human and natural disturbances, likely change as a result

Goals of reserves:

  • retain diversity of biological elements (ecosystem, biodiversity, umbrella species) and ecological processes inherent in nature that would otherwise be lost through continued habitat degradation

  • protect species or groups of species of interest, of consumptive or non-consumptive importance

  • these goals are not mutually exclusive. the more they’re integrated, the more that a particular site will function as a true reserve

  • ideally, reserve size should account for Minimum Dynamic Area (MDA)

    • Based on patch dynamics theory, MDA represents smallest area that can accommodate a complete natural disturbance regime

    • area maintains internal colonization sources and minimum extinction by maintaining a complete mosaic of patches at any given time

MDA requirements

  • Determination of Minimum Dynamic Area requires extensive empirical knowledge of site

  • MDA should be larger than the largest patch that can accommodate even rare and extreme disturbances

Small Reserves

  • small reserves may be vulnerable to disturbance

  • however, it does NOT mean small reserves are undesirable or have no conservation value

  • Small reserves of value to small species (insects and plants) that benefit from patchy spatial distribution

  • Viability of small reserves can be improved by:

    • buffer zones

    • adequate and usable corridors

    • replication of habitat areas (i.e. several similar small units)

Landscape Context and Reserve Design

  • What constitutes the surrounding non-reserve matrix?

    • industrial, residential, agricultural?

    • has consequences to conservation effectiveness of reserves

  • Reserve edge

    • administrative boundary based on political, not ecological considerations

    • false edge= more protection within reserve than outside

    • biotic vs. legal boundaries

  • Area-perimeter ratio. as A:P decreases:

    • increased edge effect, fewer interior, undisturbed habitats

    • increased need for management, more cost

  • Buffers

    • influence land-use plans around reserve

    • human intervention

      • direct and indirect

      • legal and illegal

  • Landscape context is an important consideration in the design of reserves

  • May influence specific reserve functions within surrounding non-reserve landscape

  • can have positive and negative consequences for reserves

  • mixture of threats determining I/E rates and protection of interior habitat

  • ecological and administrative or “legal” boundary of reserve can be different in size and location

    • may maximize transitional aspects of reserve boundaries

  • Generated edge- false boundary product of greater protection within the reserve and lesser protection outside

    • Generated Edge may develop at some distance from the legal boundary

      • if deep in the reserve, may reduce the effective size of the reserve

  • biotic boundaries of a reserve may commonly extend beyond the legal boundaries

  • In 7 of the 8 largest reserves of the western US, biotic boundaries exceed legal boundaries by factors of 1-10 times for MVPS (50 years) of large carnivores

  • Area/perimeter ratio of reserves important when considering boundaries

  • Low A:P ratio indicates small amount of interior habitat. Large ratio indicates considerable amount of interior habitat exists well removed from edge influences

  • Low A:P ratio implies additional costs required if small tracts of interior habitat is to be retained

    • if interior species are a conservation concern

  • High A:P ratio reserves are better but may lose interior habitat if disturbances promote increase in edge

  • Buffer zones can alleviate edge processes and benefit biodiversity content of reserves

    • buffer zones often incorporate consumptive uses

  • human activities need to be considered in analysis of reserve context

Minimum Viable Population (MVP): minimum number of individuals required for a population to have a 99% probability of persisting for 100 years.

  • Major factors influencing MVP include:

    • demographic

    • genetic

    • environmental stochasticity

  • Ways to estimate MVP size:

    1. experimental (rarely done)

    2. biogeographic patterns (e.g. percent of range occupied)

    3. theoretical models (applicability)

    4. simulation models (lack generality)

    5. genetic considerations (can be overly simplistic), need to know heterozygosity and breeding (Ne) structure)

  • Population Viability Analysis: Quantitative approach to forecast extinction risks and compare alternative management options

  • MVP highlights threshold levels that may ensure population persistence over a given interval of time. Thresholds being critical populations factors below which, inbreeding and loss of genetic variation become intractable problem for continued survival

  • Distinguishes between deterministic extinction and stochastic extinction

    • Deterministic extinction is based on a single set of assumptions

    • Stochastic extinction is based on random elements

Four Types of variation that contribute independently to extinction:

  1. Population Stochasticity-chance events in survival and reproduction

  2. Genetic Stochasticity-fluctuations in gene frequencies due to influence of factors such as founder effect and inbreeding depression

  3. Environmental Stochasticity-random variation in habitat conditions and population levels of predators, pathogens, parasites, and competitors

  4. Natural Catastrophes-random events in the physical environment (earthquake, hurricane, volcanic eruption, etc)

  • Variation types 1 and 2 may become particularly significant as a population becomes gradually smaller in size

Nodes, Networks and Multiple Use Modules

  • isolated protected areas rarely reflect regional biodiversity

  • regional reserve system often critical for biodiversity conservation

  • Node: high conservation value, many endemic species, critical resources including indigenous knowledge

  • Networks: nodes connected by corridors of suitable habitat

  • MUMs: multiple-use-modules-formed core areas surrounded by buffer zones of increasingly heavy use

  • core areas are off limits to any use beyond that of indigenous peoples

IUCN Protected Area Categories

  • Ia- Natural reserves for scientific research

  • Ib- Wilderness areas

  • Il- National parks

  • Ill- Natural monuments

  • IV- habitat/species management areas

  • V- protected landscapes/seascapes (conservation and recreation)

  • VI- managed resource protected areas

  • types:

    • environmental

    • remnant

    • introduced

    • disturbance

    • regenerated

  • functions

    • habitat

    • conduit

    • sink

    • source

    • filter/barrier

  • READ: Corridors restore animal-mediated pollination in fragmented tropical forest landscapes

    • experimental approach tested corridor effects on hummingbird (and pollen) movements. Sites consisted of forest patches surrounded by pasture and a living fencerow

    • a central artificial “flower” treated with pollen analogue (fluorescent dye) encircled by three ‘pollen receiver’ flowers placed at equal distances (range 40-120 m)

    • ‘pollen receivers’ differed in type of intervening land cover to ‘pollen donor’: forest, corridor or pasture

    • animal-mediated pollination required for >94% tropical plant species, 75% of major global food crops

    • field experiment demonstrated corridors boosted forest-associated pollinator availability (hummingbirds)

    • corridors increased visitation frequency by forest hummingbirds, no difference for generalists

Aims and Objectives of Reintroductions

  • Aims

    • establish viable populations in the wild of species, subspecies or race which has become either locally extinct, or extirpated

    • organisms should be reintroduced within natural habitat and native range and require minimal long-term management

  • Objectives

    1. Enhance long-term survival of a species

    2. Re-establish a keystone species (ecological and cultural sense)

    3. Maintain and/or restore natural biodiversity

    4. provide long-term economic benefits to the local and/or nation economy

    5. promote conservation awareness

IUCN Translocation Categories

  • 1. Reintroduction: reestablishment of a species to portions of its range where extirpated or locally extinct

  • 2. Re-enforcement/supplementation: adding individuals to an existing population

  • 3. Conservation/Benign Introduction: establish species outside their known geographic range for conservation purposes only, but within appropriate habitat and ecogeographical area

  • Category #3 is a feasible conservation tool only when no remaining area left within a species’ historic range

Reasons for Translocation

  1. Make use of individuals who would otherwise be lost

  2. restore community or ecosystem processes or increase populations in protected habitats

  3. Develop new approaches and techniques

  4. Genetics aspects of translocation broadly divided into:

    a. aspects associated with composition of source population (e.g. heterozygosity)

    b. problems may emerge if introduced individuals interbreed with conspecific residents (e.g. outbreeding depression)

Final Thoughts-

  1. Importance of Partnerships

    • Current global trends aimed at decentralizing reserve design

    • works best when mutual interests and mutual benefits coincide

    • if effective, it broadens “ownerships” and promotes conservation effectiveness

    • not necessarily a means to an end, but a process to better outcomes

    • USFWS Migratory Bird Joint Ventures is a very good example of these partnerships.

      • collaborative, regional partnerships

      • government agencies, NGOs, private corporations, tribes, and individuals

      • conserve habitat for benefit of priority bird species, other wildlife, and people

    • LMV-JV partnership as example of regional conservation planning efforts.

    • Uses available data to prioritize areas in the MAV for conservation delivery.

    • Mini-partnerships within prioritized areas called Conservation Delivery Networks.

    • Delivery networks consist of local entities that work together to implement conservation.

  2. Importance of Monitoring

    • Benefits:

      • builds and maintains support for protected areas

      • helps refine management strategies

      • way to optimize needs

      • can help lead to informed choices

      • Northern Gulf of Mexico waterbird monitoring program established following Deep Water Horizon oil spill

      • Frequently, there can be resistance from partners to provide funding for monitoring conservation activities

        • improves adaptive management options and outcomes of conservation design

  3. Importance of Local Communities

    • Local communities should be fully involved in the reserve process.

      • planning and management

    • needs of community need to be assessed and incorporated

    • coordination and support of traditional/sustainable land use

    • retaining subsistence activities should be assured and encouraged

    • Employing and training staff recruited from local communities often improves reserve effectiveness

      • nature guides

      • anti-poaching patrols (timber, wildlife)

      • support staff (maintenance, cooking)

Benefits and Challenges of Marine Protected Areas

  • Overall effect of 12 MPAs around the world evaluated

  • Overall abundance of fish inside marine reserves up to 3.7 times greater

  • Interest in MPAs continues, efforts focusing on strategically designing MPAs

Challenges of Marine Protected Areas

  • Limited understanding of population and community dynamics of species targeted by MPA

  • Greater diversity of trophic levels

  • Very large scale of connectivity (open systems)

  • Haphazard design and implementation

  • Limited to no enforcement

  • Monitoring/evaluation costly and logistically challenging

  • Jurisdictional uncertainty/governance challenges

  • Poorly-defined rights/use limitations

  • Direct exploitation (Law of the Sea “innocent passage”)

  • Disproportionate global scope (1.2% of world’s ocean surface)