Spatial Variance in Ecology

Horne, John K.; Schneider, David C.

doi:10.2307/3545670

Cited by 121 publications

(72 citation statements)

References 124 publications

(104 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The evaluation of aggregation indices depends on the measurement scale and applies to all methods that quantify the spatial variance of the distribution of any organism (Horne and Schneider, 1995). Curtis and Mcintosh (1950) and later Pielou (1969) and Greig-Smith (1983) demonstrated the dependence of several indices on the measurement scale.…”

Section: Discussionmentioning

confidence: 99%

Spatial distribution of earthworms in acid-soil savannas of the eastern plains of Colombia

Jiménez

Rossi²,

Lavelle³

2001

Applied Soil Ecology

View full text Add to dashboard Cite

The horizontal spatial distribution of earthworms in a native savanna and in a 17 year introduced pasture from the area of Carimagua (Colombia) was assessed by means of aggregation indices and geostatistical analysis. Morisita's index (I d ) and Taylor's index (b) were calculated from field data obtained through 1 m 2 quadrats during a sampling period of 17 months and both semivariograms and contour maps were obtained at three different dates through a rapid sampling of 64, 40 cm × 40 cm × 15 cm soil blocks, regularly distributed in the nodes of a 8 × 8 grid (i.e. 70 m × 70 m). Earthworms tended to exhibit contagious distribution in both land use systems and a multivariate relationship appeared between the size of the earthworm and aggregation indices employed. Land use had no significant effect on the spatial distribution of earthworms. Earthworms belonging to different ecological categories and from diverse sizes were spatially distributed in patches of several tens of meters. Semivariograms reflected, occasionally, the size of these patches, although, no spatial structure was perceived at some dates. This might be due to the intersample distance employed (10 m) so that changing the scale of observation could reflect unseen patterns.In this study our purpose was first to determine the strength of spatial aggregation in some Neotropical earthworm species and then to observe the movement of population patches at the scale of the studied area. The use of these types of spatial analyses in conjunction may be very useful to establish the dynamics of earthworm populations in the field.

show abstract

Section: Discussionmentioning

confidence: 99%

Spatial distribution of earthworms in acid-soil savannas of the eastern plains of Colombia

Jiménez

Rossi²,

Lavelle³

2001

Applied Soil Ecology

View full text Add to dashboard Cite

show abstract

“…There are several methods used to observe the spatial variance of plankton (Jone & Francis, 1982) such as variance s 2 of a quantity x, Morisita's index and Tayloris Power Law (Horne & Schneider, 1995). Considering Morisita's index was independent of population density and sample size, we used it to detect the spatial dispersion in the vertical water column (Martin-Smith & Vincent, 2005;Thackeray et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

Daily and vertical dynamics of rotifers under the impact of diatom blooms in the Three Gorges Reservoir, China

Zhou

Cai

et al. 2011

Hydrobiologia

View full text Add to dashboard Cite

The Three Gorges Dam was built in 2005 with a storage capacity of 39.3 billion m 3 , ranking 22nd in the world. However, since the impoundment of the reservoir, serious blooms of phytoplankton have occurred. Rotifers, having a key role in the freshwater aquatic food web, are important grazers of phytoplankton and an essential food resource to higher trophic consumers. To explore the impacts of phytoplankton blooms on the rotifer community, daily and vertical surveys of rotifers were conducted in a bay of the Three Gorges Reservoir (Xiangxi Bay). Altogether 46 rotifer species were registered, and Synchaeta tremula, Polyarthra vulgaris, and Brachionus calyciflorus were the most abundant species accounting for 36, 26, and 16% of the mean rotifer densities, respectively. Although these dominant species always prevailed in the rotifer community, their proportions changed significantly from non-bloom phase to bloom phase, e.g., the significance of S. tremula deceased from 46.8 to 33.2%, while P. vulgaris and B. calyciflorus increased from 23.9 and 13.9% to 26.2 and 16.2%, respectively. In the vertical water column, all the rotifer following phytoplankton displayed an aggregated distribution, concentrating at the upper layers (0.5-5 m), especially during the bloom phase. From the non-bloom phase to the bloom phase, rotifer densities, the dominant rotifers, Shannon-Wiener and Margalef's diversity increased significantly, while the evenness displayed the opposite trend. Non-metric multidimensional scaling analysis (NMDS) revealed that the samples in the non-bloom phase were well separated from those in the bloom phase. This means that the outbreak of the diatom bloom in the Xiangxi Bay had significant impacts on the rotifer community. Further investigations are needed to address the impacts of the changes of rotifer community on higher trophic levels.

show abstract

“…General Norton de Matos s/n, 4450-208 Matosinhos, Portugal Full list of author information is available at the end of the article distribution, abundance and diversity of coastal assemblages. As a consequence, small-scale natural variability should not be considered a statistical inconvenience, but a key issue to address in order to increase ecological understanding [17].…”

Section: Open Accessmentioning

confidence: 99%

Spatial variation of reef fishes and the relative influence of biotic and abiotic habitat traits

2017

View full text Add to dashboard Cite

Patterns of distribution of reef fishes were examined across three spatial scales and related to habitat traits along 25 km of the northern Portuguese coast. Response variables included the multivariate assemblage structure, the total number of taxa and individuals, and the abundance of single groups categorized according to their preference for the benthic, proximo-benthic or pelagic environment, feeding and reproductive behaviour. Habitat traits included topographic elements (small and large 'drops' like cracks and crevices) and the extent of dominant morpho-functional types of macroalgae (kelp, large foliose, small erect, turf-forming filamentous, and encrusting). All fish responses were characterized by the largest variance at the smallest scale (among transects tens m apart), followed by that among reefs (hundreds m to 1 km apart) and almost null variance among sites (some km apart). Small and large 'drops' of the substratum explained, respectively, considerable variation of assemblage structure and the total abundance of individuals, while the extent of bare rock influenced the richness of taxa and that of benthic fishes, fishes feeding on sessile invertebrates and fishes laying benthic eggs or having nesting behaviour. Combinations of abiotic and biotic structural attributes of reefs influenced proximo-benthic fishes, the predators of mobile animals and fishes releasing pelagic eggs. The here reported associations between patterns of distribution of reef fishes and habitat traits have implications for the design of future protection schemes suitable to guarantee the conservation of reef fish communities and of the processes responsible for their variation. Within the SLOSS (single-large vs. several-small) debate in the design of marine reserves, for example, effective protection to the studied reef fishes would be provided by a set of small reserves, rather than a single large which might be appropriate for fishes having wider home ranges.

show abstract

Spatial Variance in Ecology

Cited by 121 publications

References 124 publications

Spatial distribution of earthworms in acid-soil savannas of the eastern plains of Colombia

Spatial distribution of earthworms in acid-soil savannas of the eastern plains of Colombia

Daily and vertical dynamics of rotifers under the impact of diatom blooms in the Three Gorges Reservoir, China

Spatial variation of reef fishes and the relative influence of biotic and abiotic habitat traits

Contact Info

Product

Resources

About