Patch dynamics
Encyclopedia
Patch dynamics is a conceptual approach to ecosystem
and habitat analysis that emphasizes dynamics of heterogeneity within a system (i.e. that each area of an ecosystem is made up of a mosaic of small 'sub-ecosystems').
Diverse patches of habitat created by natural disturbance regimes are seen as critical to maintenance of diversity (ecology). A habitat patch is any discrete area that is used by a species for breeding or obtaining other resources. http://www.jstor.org/view/08888892/di995160/99p00105/1?frame=noframe&userID=a9e922ee@ucsc.edu/01cc99331100501bfbcaa&dpi=3&config=jstor They have a definite shape and spatial configuration, or heterogeneity.
Mosaics are the patterns within landscapes that are composed of smaller elements, such as individual forest stands, shrubland patches, highways, farms, or towns.
. This focus centered around the idea that the status of a particular population
, community
, or ecosystem
could be understood by studying a particular patch within a mosaic. However, this perception ignored the conditions that interact with, and connect patches. In 1979, Bormann and Likens coined the phrase shifting mosaic to describe the theory that landscapes change and fluctuate, and are in fact dynamic. This is related to the battle of cells that occurs in a Petri dish
.
Patch dynamics refers to the concept that all landscapes are dynamic. There are three states that a patch can exist in: potential, active, and degraded. Patches in the potential state are transformed into active patches through colonization of the patch by dispersing species arriving from other active or degrading patches. Patches are transformed from the active state to the degraded state when the patch is abandoned, and patches change from degraded to potential through a process of recovery. http://72.14.253.104/search?q=cache:rQRizzAWL9MJ:www.ecostudies.org/reprints/Wright_et_al_2004_Patch_Dynamics_Oikos_105_336-348.pdf+patch+dynamics&hl=en&ct=clnk&cd=3&gl=us&client=safari
Logging, fire, farming, and reforestation
can all contribute to the process of colonization, and can effectively change the shape of the patch. Patch dynamics also refers to changes in the structure, function, and composition of individual patches that can, for example, effect the rate of nutrient cycling.
Patches are also linked, although separated from other patches, migration occurs from one patch to another. This migration maintains the population of some patches, and can be the mechanism by which some plant species spread. This implies that ecological systems within landscapes are open, rather than closed and isolated. (Pickett, 2006)
, disturbance
, restoration, and succession
, and the effects of human activities. In a sense, conservation is the active maintenance of patch dynamics (Pickett, 2006).
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
and habitat analysis that emphasizes dynamics of heterogeneity within a system (i.e. that each area of an ecosystem is made up of a mosaic of small 'sub-ecosystems').
Diverse patches of habitat created by natural disturbance regimes are seen as critical to maintenance of diversity (ecology). A habitat patch is any discrete area that is used by a species for breeding or obtaining other resources. http://www.jstor.org/view/08888892/di995160/99p00105/1?frame=noframe&userID=a9e922ee@ucsc.edu/01cc99331100501bfbcaa&dpi=3&config=jstor They have a definite shape and spatial configuration, or heterogeneity.
Mosaics are the patterns within landscapes that are composed of smaller elements, such as individual forest stands, shrubland patches, highways, farms, or towns.
Patches and mosaics
Historically, due to the short time scale of human observation, mosaic landscapes were perceived to be staticStasis
The term stasis may refer to* A state of stability, in which all forces are equal and opposing, therefore they cancel out each other....
. This focus centered around the idea that the status of a particular population
Population
A population is all the organisms that both belong to the same group or species and live in the same geographical area. The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals...
, community
Community
The term community has two distinct meanings:*a group of interacting people, possibly living in close proximity, and often refers to a group that shares some common values, and is attributed with social cohesion within a shared geographical location, generally in social units larger than a household...
, or ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
could be understood by studying a particular patch within a mosaic. However, this perception ignored the conditions that interact with, and connect patches. In 1979, Bormann and Likens coined the phrase shifting mosaic to describe the theory that landscapes change and fluctuate, and are in fact dynamic. This is related to the battle of cells that occurs in a Petri dish
Petri dish
A Petri dish is a shallow glass or plastic cylindrical lidded dish that biologists use to culture cells or small moss plants. It was named after German bacteriologist Julius Richard Petri, who invented it when working as an assistant to Robert Koch...
.
Patch dynamics refers to the concept that all landscapes are dynamic. There are three states that a patch can exist in: potential, active, and degraded. Patches in the potential state are transformed into active patches through colonization of the patch by dispersing species arriving from other active or degrading patches. Patches are transformed from the active state to the degraded state when the patch is abandoned, and patches change from degraded to potential through a process of recovery. http://72.14.253.104/search?q=cache:rQRizzAWL9MJ:www.ecostudies.org/reprints/Wright_et_al_2004_Patch_Dynamics_Oikos_105_336-348.pdf+patch+dynamics&hl=en&ct=clnk&cd=3&gl=us&client=safari
Logging, fire, farming, and reforestation
Afforestation
Afforestation is the establishment of a forest or stand of trees in an area where there was no forest. Reforestation is the reestablishment of forest cover, either naturally or artificially...
can all contribute to the process of colonization, and can effectively change the shape of the patch. Patch dynamics also refers to changes in the structure, function, and composition of individual patches that can, for example, effect the rate of nutrient cycling.
Patches are also linked, although separated from other patches, migration occurs from one patch to another. This migration maintains the population of some patches, and can be the mechanism by which some plant species spread. This implies that ecological systems within landscapes are open, rather than closed and isolated. (Pickett, 2006)
Conservation efforts
Recognizing the patch dynamics within a system is needed for conservation (ecology) efforts to succeed. Successful conservation includes understanding how a patch changes and predicting how they will be affected by external forces. These externalities include natural effects, such as land useLand use
Land use is the human use of land. Land use involves the management and modification of natural environment or wilderness into built environment such as fields, pastures, and settlements. It has also been defined as "the arrangements, activities and inputs people undertake in a certain land cover...
, disturbance
Disturbance
In ecology, a disturbance is a temporary change in average environmental conditions that causes a pronounced change in an ecosystem. Outside disturbance forces often act quickly and with great effect, sometimes resulting in the removal of large amounts of biomass...
, restoration, and succession
Ecological succession
Ecological succession, is the phenomenon or process by which a community progressively transforms itself until a stable community is formed. It is a fundamental concept in ecology, and refers to more or less predictable and orderly changes in the composition or structure of an ecological community...
, and the effects of human activities. In a sense, conservation is the active maintenance of patch dynamics (Pickett, 2006).
See also
- Conservation biologyConservation biologyConservation biology is the scientific study of the nature and status of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction...
- Edge effectEdge effectThe edge effect in ecology is the effect of the juxtaposition or placing side by side of contrasting environments on an ecosystem.This term is commonly used in conjunction with the boundary between natural habitats, especially forests, and disturbed or developed land. Edge effects are especially...
- Habitat conservationHabitat conservationHabitat conservation is a land management practice that seeks to conserve, protect and restore, habitat areas for wild plants and animals, especially conservation reliant species, and prevent their extinction, fragmentation or reduction in range...
- Habitat corridorHabitat corridorA habitat corridor is a strip of land that aids in the movement of species between disconnected areas of their natural habitat. An animal’s natural habitat would typically include a number of areas necessary to thrive, such as wetlands, burrowing sites, food, and breeding grounds...
- Habitat fragmentationHabitat fragmentationHabitat fragmentation as the name implies, describes the emergence of discontinuities in an organism's preferred environment , causing population fragmentation...
- Island biogeographyIsland biogeographyIsland biogeography is a field within biogeography that attempts to establish and explain the factors that affect the species richness of natural communities. The theory was developed to explain species richness of actual islands...
- Landscape ecologyLandscape ecologyLandscape ecology is the science of studying and improving relationships between urban development and ecological processes in the environment and particular ecosystems...
- Spatial ecologySpatial ecologySpatial ecology is a specialization of ecologyand geography that is concerned with the identification of spatial patterns and their relationships to ecological events. In spatial ecology, ecological events can be explained through the detection of patterns at a given spatial scale; local,...
External links
- http://www.jstor.org/view/08888892/di995160/99p00105/1?frame=noframe&userID=a9e922ee@ucsc.edu/01cc99331100501bfbcaa&dpi=3&config=jstor
- http://72.14.253.104/search?q=cache:rQRizzAWL9MJ:www.ecostudies.org/reprints/Wright_et_al_2004_Patch_Dynamics_Oikos_105_336-348.pdf+patch+dynamics&hl=en&ct=clnk&cd=3&gl=us&client=safari
- http://ieeexplore.ieee.org/iel5/5992/30777/01425395.pdf?isnumber=&arnumber=1425395