Priority effects and species sorting in a long paleoecological record of repeated community assembly through time

Abstract

Abstract. We studied the relative roles of environmental species sorting and priority effects in the assembly of ecological communities on long time scales, by analyzing community turnover of water fleas (Daphnia) in response to strong and recurrent environmental change in a fluctuating tropical lake. During the past 1800 years, Lake Naivasha (Kenya) repeatedly fluctuated between a small saline pond habitat during lowstands and a large freshwater lake habitat during highstands. Starting from a paleoecological reconstruction, we estimated the role of priority effects in Daphnia community assembly across 16 of these habitat turnovers and compared this with the response of the community to reconstructed changes in three environmental variables important for species sorting.Our results indicate that the best predictor of Daphnia community composition during highstands was the community composition just prior to the transition from lowstands to highstands. This reflects a long-lasting priority effect of late lowstand communities on highstand communities, arising when remnant lowstand populations fill newly available ecological space in the rapidly expanding lake habitat. Species sorting and priority effects had a comparable but relatively small influence on community composition during the lowstands. Moreover, these priority effects decayed rapidly with time as Daphnia communities responded to environmental change, in contrast with the highstand communities where priority effects lasted for several decades.

Effects of dispersal and selection on stochastic assembly in microbial communities

“…Despite this possibility, there is no support that this priority effect would be stronger under suboptimal conditions or strong environmental selection (here, higher lignin/N). In general, priority effects are stronger in communities with high productivity or turnover (Fukami, 2015), or after experiencing a disturbance or environmental shift (Mergeay et al, 2011), none of which describe high lignin/N scenarios.…”

The legacy of the past: effects of historical processes on microbial metacommunities

“…Most importantly, legacy effects will primarily be influenced by the adaptive potential and growth rates of local communities in relation to the time it takes for better adapted external taxa and/or dormant resident taxa to arrive or resuscitate and grow to become abundant community members. This will then ultimately determine the relative importance of contemporary species sorting processes compared to historical processes (Urban & De Meester 2009, Mergeay et al 2011, Fukami 2015, Vanoverbeke et al 2015, Grainger & Gilbert 2016. If dispersal rates are high and dispersed taxa that are selected by the new environmental conditions grow rapidly, the time window for which the legacy of past environmental conditions can be detected should be short (Fig.…”

Influence of genetic variability and external regulating factors on amyloid-beta peptide aggregation

“…3.1B and C). The position and width of this peak have been related to the number of β-strands and the formation of H-bonds (52)(53)(54). Both peptides also showed an additional minor peak around 1695 cm -1 at early aggregation time points (0 h, 24 h).…”

“…Moreover, abnormal levels of hyperphosphorylated tau are causative of a group of neurodegenerative disorders referred to as tauopathies (52). Therefore, tau is also targeted in therapeutic development for AD (53), albeit considerably less than Aβ. Another alternative view deems that several AD pathogenic features can be interpreted as amyloid-independent alterations of synaptic plasticity, endolysosomal trafficking, cell cycle regulation, and neuronal survival (54).…”

“…For instance, age-structured population models (52) developed in ecology may help to understand the development of molecules from precursors and how this can be modified by changing environmental conditions. Time series data combined with trials that alternate the order of treatments/introduction of interactors in a complex system, can help to assess to what extent history matters in determining the deterministic outcome of species or molecule interactions (53).…”