Spatial heterogeneity is a property generally ascribed to a

landscape A landscape is the visible features of an area of land, its landforms, and how they integrate with natural or man-made features, often considered in terms of their aesthetic appeal.''New Oxford American Dictionary''. A landscape includes the ...

or to a

population Population typically refers to the number of people in a single area, whether it be a city or town, region, country, continent, or the world. Governments typically quantify the size of the resident population within their jurisdiction usi ...

. It refers to the uneven distribution of various concentrations of each

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

within an area. A landscape with spatial heterogeneity has a mix of concentrations of multiple species of plants or animals (biological), or of

terrain Terrain or relief (also topographical relief) involves the vertical and horizontal dimensions of land surface. The term bathymetry is used to describe underwater relief, while hypsometry studies terrain relative to sea level. The Latin word ...

formations (geological), or environmental characteristics (e.g. rainfall, temperature, wind) filling its area. A population showing spatial heterogeneity is one where various concentrations of individuals of this species are unevenly distributed across an area; nearly synonymous with "patchily distributed."

Examples

Environment Environment most often refers to: __NOTOC__ * Natural environment, all living and non-living things occurring naturally * Biophysical environment, the physical and biological factors along with their chemical interactions that affect an organism or ...

s with a wide variety of

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

s such as different topographies,

soil type A soil type is a taxonomic unit in soil science. All soils that share a certain set of well-defined properties form a distinctive soil type. Soil type is a technical term of soil classification, the science that deals with the systematic categori ...

s, and

climate Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologi ...

s are able to accommodate a greater amount of

. The leading scientific explanation for this is that when organisms can finely subdivide a landscape into unique suitable habitats, more species can coexist in a landscape without competition, a phenomenon termed "niche partitioning." Spatial heterogeneity is a concept parallel to

ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syst ...

productivity, the species richness of

animal Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and go through an ontogenetic stage ...

s is directly related to the species richness of

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae excl ...

s in a certain habitat.

Vegetation Vegetation is an assemblage of plant species and the ground cover they provide. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic charac ...

serves as food sources,

s, and so on. Therefore, if vegetation is scarce, the animal populations will be as well. The more plant species there are in an ecosystem, the greater variety of

microhabitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

s there are. Plant species richness directly reflects spatial heterogeneity in an ecosystem.

Types

Spatial heterogeneity could be either local or stratified, the former is called spatial local heterogeneity, referring to the phenomena that the value of an attribute at one site is different from its surrounding, such as hotspot or cold spot; the latter is called spatial stratified heterogeneity, referring to the phenomena that the within strata variance is less than the between strata variance, such as ecological zones and landuse classes.

Testing

Spatial local heterogeneity can be tested by LISA, Gi and SatScan, while spatial stratified heterogeneity of an attribute can be measured by geographical detector ''q''-statistic: :

q = 1 - \frac\sum_^LN_h\sigma_h^2

where a population is partitioned into ''h'' = 1, ..., ''L'' strata; ''N'' stands for the size of the population, σ² stands for variance of the attribute. The value of ''q'' is within

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0 indicates no spatial stratified heterogeneity, 1 indicates perfect spatial stratified heterogeneity. The value of ''q'' indicates the percent of the variance of an attribute explained by the stratification. The ''q'' follows a noncentral ''F'' probability density function. Q-fig2

Models

Spatial stratified heterogeneity

Optimal parameters-based geographical detector

Optimal Parameters-based Geographical Detector (OPGD) characterizes spatial heterogeneity with the optimized parameters of spatial data discretization for identifying geographical factors and interactive impacts of factors, and estimating risks.

Interactive detector for spatial associations

Interactive Detector for Spatial Associations (IDSA) estimates power of interactive determinants (PID) on the basis of spatial stratified heterogeneity, spatial autocorrelation, and spatial fuzzy overlay of explanatory variables.

Geographically optimal zones-based heterogeneity

Geographically Optimal Zones-based Heterogeneity (GOZH) explores individual and interactive determinants of geographical attributes (e.g., global soil moisture) across a large study area based on the identification of explainable geographically optimal zones.

Robust geographical detector

Robust Geographical Detector (RGD) overcomes the limitation of the sensitivity in spatial data discretization and estimates robust power of determinants of explanatory variables.

Terminology

Spatial heterogeneity can be re-phrased as scaling hierarchy of far more small things than large ones. It has been formulated as a scaling law. Spatial heterogeneity or scaling hierarchy can be measured or quantified by ht-index: a head/tail breaks induced number. Jiang B. 2013. Head/tail breaks: A new classification scheme for data with a heavy-tailed distribution, The Professional Geographer, 65 (3), 482 – 494.

References

{{DEFAULTSORT:Spatial Heterogeneity Ecosystems Spatial analysis