Relationships between taxonomic resolution and spatial scales of multivariate variation

Abstract

Summary 1.We investigated the effects of changes in taxonomic resolution on analyses of patterns of multivariate variation at different spatial scales for the highly diverse fauna inhabiting holdfasts of the kelp Ecklonia radiata . 2. Multivariate analyses were performed using several transformations to examine differences in spatial patterns of variation from metres up to hundreds of kilometres for composition vs. relative abundance in assemblages. 3. The greatest variability in assemblages occurred at the smallest spatial scale, from plant to plant, pointing to the existence of important small-scale processes. The proportional amount of variation at the smallest spatial scale decreased with decreasing taxonomic resolution (i.e. from species through to phyla). For composition, the next-greatest source of variation was at the largest spatial scale (hundreds of kilometres), while for relative abundance, the next-greatest source of variation was at the level of sites (hundreds of metres to kilometres). 4. For abundance data, location-level variation became less important and site-level variation became more important with decreasing taxonomic resolution, while for compositional data, the opposite pattern occurred. This suggests that variation in the presence of species or taxa at a particular location along the coast is driven by large-scale processes, while variation in relative abundances within locations is driven by mediumscale processes. 5. The lack of significant variation in the proportional abundances of phyla at large spatial scales suggests that some consistency of pattern may emerge at larger scales (spatial and/or taxonomic), even in the presence of high small-scale variability. These findings strengthen the idea that substantial local variation need not preclude the existence of broad-scale organization in ecological patterns and biodiversity.

Spatial variability in intertidal macroalgal assemblages on the North Portuguese coast: consistence between species and functional group approaches

“…Sedimentation, dispersal of propagules and post settlement processes such as competition, grazing and desiccation are potential factors that can explain variation on small spatial scales (Coleman 2002). Moreover, Anderson et al (2005a) have indicated that small-scale heterogeneity of habitat, differential settlement cues or patchy disturbance and succession may explain patchiness at smaller spatial scales. Only future manipulative experiments will provide a cause effect relationship between the high small-scale variability observed and the potential processes mentioned, but small-scale heterogeneity of habitat is the process more likely to be operating in this particular system, especially because our sampling did not consider a homogeneity of the substrate.…”

Atlantic Salmon (Salmo salar L.) Gastrointestinal Microbial Community Dynamics in Relation to Digesta Properties and Diet

“…PRIMER6 and PERMANOVA+ (version 6.1.12 and version 1.0.2; Primer-E, Ivybridge, UK), respectively were used to conduct permutation multivariate analysis of variance (PERMANOVA) [49], and canonical analysis of principal coordinates (CAP) [50]. For this analysis sequence read data organised at the genus-level was normalised as percentages, square root transformed and a resemblance matrix created by calculation of Bray-Curtis coefficients.…”

Patterns of distribution of annelids: taxonomic and spatial inconsistencies between two biogeographic provinces and across multiple spatial scales

“…These studies have incorporated diverse taxa that have not all been identified to the same level of resolution and 'species' and may include many taxa identified to genus, family or even phylum (e.g. Anderson et al 2005). This problem can be overcome by testing such ideas with well-described taxa, such as annelids.…”

“…Small-scale local processes, such as competition or predation, are likely to cause variation in populations of individual species at scales of centimetres to 100s of metres (Underwood & Chapman 1996). Largescale processes, such as historical events, biogeography, or effects of average temperature, may be readily identifiable as changes in taxa grouped into genera or families (Levin 1992) because large amounts of small-scale variability among individual species are generally thought to flatten or average out as data are accumulated over larger scales and longer times (Warwick 1988, Anderson et al 2005 such that impacts are manifest at higher taxonomic levels (Ferraro & Cole 1990, Olsgard et al 1998.…”