Spatial heterogeneity as a multiscale characteristic of zooplankton community

Abstract

Key words: marine and freshwater zooplankton, spatial heterogeneity, scaling, multiple abiotic and biotic generative processes . AbstractZooplankton spatial heterogeneity has profound effects on understanding and modelling of zooplankton population dynamics and interactions with other planktonic compartments, and consequently, on the structure and function of planktonic ecosystems . On the one hand, zooplankton heterogeneity at spatial and temporal scales of ecological interest is an important focus of aquatic ecology research because of its implications in models of productivity, herbivory, nutrient cycling and trophic interactions in planktonic ecosystems . On the other hand, estimating zooplankton spatial variation at the scale of an ecosystem, is a powerful tool to achieve accurate sampling design . This review concentrates on the spatial heterogeneity of marine and freshwater zooplankton with respect to scale . First to be examined are the concept of spatial heterogeneity, the sampling and statistical methods used to estimate zooplankton heterogeneity, and the scales at which marine and freshwater zooplankton heterogeneity occurs . Then, the most important abiotic and biotic processes driving zooplankton heterogeneity over a range of spatial scales are presented and illustrated by studies conducted over large and fine scales in both oceans and lakes . Coupling between abiotic and biotic processes is finally discussed in the context of the `multiple driving forces hypothesis' .Studies of zooplankton spatial heterogeneity refer both to the quantification of the degree of heterogeneity (`measured heterogeneity') and to the estimation of the heterogeneity resulting from the interactions between the organisms and their environment ('functional heterogeneity') (Kolasa & Rollo, 1991) . To resolve the problem of measuring zooplankton patchiness on a wide range of spatial scales, advanced technologies (acoustic devices, the Optical Plankton Counter (OPC), and video systems) have been developed and tested in marine and freshwater ecosystems . A comparison of their potential applications and limitations is presented . Furthermore, many statistical tools have been developed to estimate the degree of `measured heterogeneity' ; the three types most commonly used are indices of spatial aggregation, variance : mean ratio, and spatial analysis methods . The variance partitioning method proposed by Borcard et al. (1992) is presented as a promising tool to assess zooplankton `functional heterogeneity' .Nested patchiness is a common feature of zooplankton communities and spatial heterogeneity occurs on a hierarchical continuum of scales in both marine and freshwater environments . Zooplankton patchiness is the product of many physical processes interacting with many biological processes . In marine systems, patterns of zooplankton patchiness at mega-to macro-scales are mostly linked to large advective vectorial processes whereas at coarse-, fine-and micro-scales, physical turbulence and migratory, reproductive and swarm behavio...

Variability inCalanusspp. abundance on fine- to mesoscales in an Arctic fjord: implications for little auk feeding

“…Patchiness has long been recognized as a biologically significant trait in plankton ecology (Hardy 1936;Pinel-Alloul 1995), and recently ecological effects of patchiness on different scales have received increasing attention, in particular with regard to predatorprey relationships (Weimerskirch 2007). Our study indicates that dominating Alle alle prey aggregated in patches with a characteristic length scale of below 1.2 km (Table IV).…”

“…For this particular potential feeding ground a sampling grid of less than 2 km would be necessary to cover the variation in the area. Given the logistical demands associated with sampling at such resolution, modern high-resolution sampling equipment such as continuous net-plankton pumping (Molinero et al 2008), optical plankton recorder (Pinel-Alloul 1995;Currie et al 1998) and acoustics (ADCP) (Pinel-Alloul 1995;Tokarev et al 1998;Coyle 2000;Hembre & Megard 2003) are necessary complements to traditional plankton net tows. Furthermore, the heterogeneity in horizontal distribution also raises questions about the extent and nature of vertical patchiness.…”

Spatial pattern analysis of zooplankton community of Bakreswar reservoir, India

“…Field survey has also revealed that above-mentioned stations give maximum success in fishing, which also indicates the availability of resource in this area that supports the cause of clumping of zooplanktons. It has been already established that fine-scale horizontal variability in zooplankton distribution is related to the presence and feeding of planktivorous fish (Pinel-Alloul 1995;Jeppesen et al 1997;Romero et al 2004). In Bakreswar reservoir, clumping of cladocerans and copepods is high in Stations I Index of dispersion is based on sampling units and its size and thus has some limitations in predicting the exact distribution pattern for organisms with continuous distribution.…”

Responses of crustacean zooplankton to seasonal and tidal salinity changes in the coastal Lake Waihola, New Zealand

“…Although many zooplankton are actively mobile, creating patches over small spatial scales, most zooplankton are considered to be primarily "passive drifters" with respect to large-scale water movement (Pinel-Alloul 1995;Wiafe & Frid 1996). The use of drogues and surface drifters to track water currents is common in marine systems (Wiafe & Frid 1996;Carr & Rossby 2001), and this technique may be transferred to the measurement of currents in other waterbodies.…”