Spatial Heterogeneity, Resource Richness and Species Diversity

2020 ◽  
pp. 98-138
Keyword(s):  
Species Diversity ◽  
Spatial Heterogeneity

scholarly journals Spectral Heterogeneity Predicts Local-Scale Gamma and Beta Diversity of Mesic Grasslands

2019 ◽  
Vol 11 (4) ◽  
pp. 458 ◽  
Author(s):  
H. Polley ◽  
Chenghai Yang ◽  
Brian Wilsey ◽  
Philip Fay
Keyword(s):  
Optical Properties ◽  
Species Diversity ◽  
Spatial Heterogeneity ◽  
Plant Species ◽  
Near Infrared ◽  
Spatial Scales ◽  
Ground Level ◽  
Silty Clay ◽  
Least Squares Regression ◽  
Β Diversity

Plant species diversity is an important metric of ecosystem functioning, but field assessments of diversity are constrained in number and spatial extent by labor and other expenses. We tested the utility of using spatial heterogeneity in the remotely-sensed reflectance spectrum of grassland canopies to model both spatial turnover in species composition and abundances (β diversity) and species diversity at aggregate spatial scales (γ diversity). Shannon indices of γ and β diversity were calculated from field measurements of the number and relative abundances of plant species at each of two spatial grains (0.45 m2 and 35.2 m2) in mesic grasslands in central Texas, USA. Spectral signatures of reflected radiation at each grain were measured from ground-level or an unmanned aerial vehicle (UAV). Partial least squares regression (PLSR) models explained 59–85% of variance in γ diversity and 68–79% of variance in β diversity using spatial heterogeneity in canopy optical properties. Variation in both γ and β diversity were associated most strongly with heterogeneity in reflectance in blue (350–370 nm), red (660–770 nm), and near infrared (810–1050 nm) wavebands. Modeled diversity was more sensitive by a factor of three to a given level of spectral heterogeneity when derived from data collected at the small than larger spatial grain. As estimated from calibrated PLSR models, β diversity was greater, but γ diversity was smaller for restored grassland on a lowland clay than upland silty clay soil. Both γ and β diversity of grassland can be modeled by using spatial heterogeneity in vegetation optical properties provided that the grain of reflectance measurements is conserved.

Resource Partitioning and Biodiversity in Fractal Environments with Applications to Dryland Communities

2005 ◽  
Author(s):  
Mark E. Ritchie ◽  
Han Olff
Keyword(s):  
Species Diversity ◽  
Spatial Heterogeneity ◽  
Resource Partitioning ◽  
Spatial Scales ◽  
Desert Shrubs ◽  
Physical Environments ◽  
Distribution Of Resources ◽  
Islands Of Fertility ◽  
Body Sizes ◽  
Resource Patches

Arid and semiarid ecosystems (drylands) often contain a higher diversity of animals and plants than would be expected from their low productivity. High spatial heterogeneity of resources and physical habitats, exhibited at a wide range of spatial scales (Rundel 1996, Holling 1992, Peterson et al. 1998), may be a major factor explaining such high diversity. For example, at extremely small scales (<10 cm), branched plant material and various soil physical processes can create spatial niches for invertebrates, cyanobacteria, and other cryptogamic organisms (Lightfoot and Whitford 1991). At somewhat larger scales (<10 m), desert shrubs may aggregate water and organic material in “islands of fertility,” yielding a highly patchy heterogeneous distribution of resources (e.g., seeds, water) for other plants and animals (Gibbens and Beck 1988, Halvorson et al. 1997, chapter 13 this volume, chapter 11 this volume). At even larger scales (>100 m), soil erosion patterns create topographic variation that locally concentrates available water and nutrients, yielding a marked heterogeneity in the distribution of productivity across the landscape (Milne 1992). These heterogeneous distributions of physical environments, biotic material, and resources are likely to have strong effects on biodiversity. Ecologists have long associated greater spatial heterogeneity with higher species diversity (MacArthur 1964; Brown 1981; May 1988). Within a particular physical environment (habitat), this association exists presumably because collections of species that use similar resources, or “guilds,” can coexist whenever they can more finely divide up space and different-sized resource “packages” (Hutchinson and MacArthur 1959, Brown 1981, 1995, Morse et al. 1985, Peterson et al. 1998). The partitioning of space and different resource patches may be constrained by the different body sizes of species within guilds (Hutchinson and MacArthur 1959, Morse et al. 1985, Belovsky 1986, 1997, Brown 1995, Siemann et al. 1996). However, the mechanism by which body size and spatial heterogeneity of habitats and resources determine species diversity remains unclear (May 1988, Brown 1995, Siemann et al. 1996, Belovsky 1997). Resource partitioning and spatial heterogeneity therefore may strongly influence diversity in drylands, where, for example, well-known guilds of granivorous vertebrates and invertebrates are structured by competition for different sizes of seeds and seed patches (Brown et al. 1979, Davidson et al. 1980, 1985).

Regeneration in Quercus Pyrenaica Ecosystems After Surface Fires

1991 ◽  
Vol 1 (4) ◽  
pp. 205 ◽  
Author(s):  
L Calvo ◽  
R Tarrega ◽  
E Luis
Keyword(s):  
Species Diversity ◽  
Spatial Heterogeneity ◽  
Structural Dynamics ◽  
First Year ◽  
Herbaceous Species ◽  
Quercus Pyrenaica ◽  
Perennial Species ◽  
The Third ◽  
Surface Fires ◽  
Second Year

Early post-fire structural dynamics in three Quercus pyrenaica communities after intense fires was studied. In the first year there is a marked domination of perennial species (herbaceous or woody); afterwards, herbaceous species tend to decrease in importance and ligneous species increase. Changes in species diversity were analysed as an indicator of recovery and stability in the communities. An increase was observed in the second year, and then diversity was maintained or reduced slightly in the third and fourth years. Spatial heterogeneity tends to diminish with time.

Spatial Heterogeneity and Bird Species Diversity

Ecology ◽  
1976 ◽  
Vol 57 (4) ◽  
pp. 773-782 ◽  
Author(s):  
Roland R. Roth
Keyword(s):  
Species Diversity ◽  
Spatial Heterogeneity ◽  
Bird Species ◽  
Bird Species Diversity

scholarly journals Patterns of species diversity in different spatial scales and spatial heterogeneity on beta diversity

2020 ◽  
Vol 34 (1) ◽  
pp. 9-16
Author(s):  
Caio J. R. S. Soares ◽  
Mauricio B. Sampaio ◽  
Francisco S. Santos-Filho ◽  
Fernando R. Martins ◽  
Flavio A. M. dos Santos
Keyword(s):  
Species Diversity ◽  
Spatial Heterogeneity ◽  
Beta Diversity ◽  
Spatial Scales

Spatial heterogeneity and habitat permanence affect community assembly, structure and phenology of mayflies (Ephemeroptera) in sandpit pools

Zoosymposia ◽  
2016 ◽  
Vol 11 ◽  
pp. 205-218 ◽  
Author(s):  
PAVEL SROKA ◽  
JAN KLECKA ◽  
DAVID S. BOUKAL
Keyword(s):  
Species Diversity ◽  
Spatial Heterogeneity ◽  
Larval Development ◽  
Community Assembly ◽  
Hydrologic Regime ◽  
Model Group ◽  
Assembly Structure ◽  
Different Levels ◽  
Artificial Vegetation

Spatial heterogeneity is a factor generally considered to promote biodiversity of a given habitat. We studied a colonization of isolated, newly formed pools with different heterogeneity levels (with and without artificial vegetation) and permanence (temporary and permanent). Using mayflies (Ephemeroptera) as a model group, we estimated the effect of spatial heterogeneity on the mayfly community assembly. We found the vegetated pools to host higher species diversity and abundance. Only one species was more abundant in the pools without vegetation. Since the mayfly larvae could not migrate between treatments, differences must be caused either by preferences in female oviposition or different levels of mortality among the treatments. We recorded slightly faster and more synchronized larval development in the non-permanent pools, attributable to the temperature and hydrologic regime.

Spatial Heterogeneity of Littoral Fish Assemblages in Lakes: Relation to Species Diversity and Habitat Structure

1992 ◽  
Vol 49 (7) ◽  
pp. 1493-1500 ◽  
Author(s):  
Barbara J. Benson ◽  
John J. Magnuson
Keyword(s):  
Species Diversity ◽  
Species Composition ◽  
Spatial Heterogeneity ◽  
Fish Community ◽  
Fish Assemblages ◽  
Randomization Test ◽  
Data Matrix ◽  
Depth Gradient ◽  
Fish Species Composition ◽  
Number Of Individuals

We quantified the spatial heterogeneity in nearshore fish community composition within six Wisconsin lakes and examined its relation to habitat heterogeneity and species diversity. Fish abundance was estimated annually (1981–84) using seines at six sites in each lake. Substrate type, macrophyte growth form, and depth gradient were noted at each site. Species richness was estimated as the expected number of species when the number of individuals was held constant over lakes (rarefaction). Fish community spatial heterogeneity (the average percent dissimilarity in fish species composition over all possible pairs of seine sites within a lake) differed among lakes; it was positively correlated with within-lake variation in the depth gradient and with species diversity as estimated by rarefaction. We tested whether differences in community spatial heterogeneity among lakes resulted simply from differences in species diversity using a randomization test based on random permutations of the rows (seine hauls) in the species composition data matrix. Lakes differed in the extent to which the observed community heterogeneity exceeded the randomization results. Spatial heterogeneity of the fish community, as opposed to sampling phenomena resulting from differences in richness, was a strong factor in some lakes.

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