The role of local and regional processes on population synchrony along the gradients of habitat specialization

Abstract

Citation: Pandit, S. N., K. Cottenie, E. C. Enders, and J. Kolasa. 2016. The role of local and regional processes on population synchrony along the gradients of habitat specialization. Ecosphere 7(5):e01217. 10. 1002/ecs2.1217 Abstract. Metacommunity perspective highlights the role of space as a factor contributing to local community structure and dynamics. Often tests of metacommunity models rely on snapshot patterns of species distribution and abundance. Such patterns may introduce biases because they overlook differences in responses of constituent species to changing environmental conditions, particularly when such responses override patterns predicted from dispersal and biotic interactions alone. This applies, for example, to habitat generalists, whose responses to environmental variations differ from those of habitat specialists, resulting in different snapshot patterns at different times. Synchronized (i.e., correlated among sites) environmental variation is perhaps the most obvious case of environmental variation that could generate regular differences among species of different specialization. We hypothesized that synchronized environmental variation synchronizes local populations of habitat specialists to a greater degree than it does for habitat generalists as experiments have shown that habitat generalists are less sensitive to changing environmental conditions. To test this in an empirical system, we used time series data (nine annual surveys) on an invertebrate metacommunity of 49 rock pools on the coast of Jamaica. We found that population synchrony of a significant portion of 24 species sharing these rock pools increased with habitat specialization in response to environmental synchrony (represented by synchrony of environment). However, distance among rock pools, which may affect dispersal or shared perturbations, was negatively correlated with population synchrony of individual species, irrespective of their specialization. As only habitat specialists showed increasing synchrony with environmental synchrony, and both generalist and specialist synchrony were negatively correlated with distance, we infer that habitat generalists must be synchronized more by space-related processes while habitat specialists by a combination of environmental forcing and dispersal. Overall, the study suggests that species of different habitat specialization show consistent differences with respect to local processes involving environmental variations but show fewer differences with respect to regional processes involving distance, at least when long-term dynamics are concerned. Furthermore, the study identifies a rarely recognized link between variation in space and its consequences for variation in time-a link much more expressed among spatially restricted species such as habitat specialists.

Environmental distances are more important than geographic distances when predicting spatial synchrony of zooplankton populations in a tropical reservoir

“…We also found evidence for the assertion that the dynamics of abiotic variables are more synchronous than those of biological variables. Finally, we found that environmental distance was the main predictor of synchrony, reinforcing the power of the Moran effect (Koenig, ; see also Pandit et al., for a similar result using environmental synchrony). The importance of environmental similarity in synchronising population dynamics has often been suggested (Haynes et al., ) and observed in several aquatic ecosystems (Cottenie, Michels, Nuytten, & De Meester, ; Kent, Yannarell, Rusak, Triplett, & McMahon, ; Seebens et al., ).…”

“…Spatial synchrony (or temporal coherence) occurs when data on different local populations (e.g., abundance), communities (e.g., species richness) or ecosystems (e.g., primary productivity) are significantly correlated across time. Several studies have demonstrated that synchrony is a common pattern that occurs in different regions (temperate and tropical), ecosystem types (e.g., aquatic and terrestrial) and groups of organisms (Allstadt, Liebhold, Johnson, Davis, & Haynes, ; Bjørnstad, Ims, & Lambin, ; Defriez & Reuman, ; Defriez, Sheppard, Reid, & Reuman, ; Ims & Andreassen, ; Koenig, ; Lansac‐Tôha et al., ; Moran, ; Pandit, Cottenie, Enders, & Kolasa, ; Ranta, Kaitala, Lindstrom, & Linden, ; Vogt, Rusak, Patoine, & Leavitt, ). For example, since the seminal works by Magnuson, Benson, and Kratz (), Kratz et al.…”

The dependence of synchrony on timescale and geography in freshwater plankton

“…Numerous studies have documented taxonomic variability in the strength of freshwater plankton spatial synchrony (Rusak et al 1999;Lansac-Tôha et al 2008;Rusak et al 2008;Vogt et al 2011;Seebens et al 2013;Lodi et al 2014;Pandit et al 2016), but many previous studies were unable to explore multiple mechanisms, timescale structure, or geography of synchrony in explaining this taxonomic variability. We demonstrated that synchrony has an important timescale structure and a geography that will both complicate and enrich efforts to compare synchrony among species and to understand the causes and consequences of synchrony.…”

“…Prior studies of synchrony in freshwater plankton also have generally examined synchrony between different water bodies (Rusak et al ; Rusak et al ; Vogt et al ; Pandit et al ), rather than within a single water body. Using separate water bodies limits comparative investigations of drivers of synchrony (i.e., dispersal, predation, and Moran effects), as dispersal among lakes is unlikely to be sufficient to synchronize their plankton dynamics.…”

Using geography to infer the importance of dispersal for the synchrony of freshwater plankton

“…Our study complements the bulk of existing studies of synchrony in freshwater plankton in part because most previous studies have examined synchrony of populations in different water bodies, and we examine synchrony within one large reservoir. Most studies of spatial synchrony of freshwater plankton among different water bodies have supported distance-decay relationships, Moran-effect causes of synchrony, and/or species-specific variability in the strength of synchrony (Magnuson et al 1990, Rusak et al 1999, Vogt et al 2011, Pandit et al 2016). Dispersal as a mechanism of synchrony has typically been less of a focus in between-lake synchrony studies because it is unlikely that synchrony would arise from this mechanism between lakes: dispersal between lakes is probably very limited in numbers of organisms transferred.…”