Riverine phytoplankton functional groups response to multiple stressors variously depending on hydrological periods

Abstract

Rivers and related freshwater ecosystems are facing increasing natural disturbance and anthropogenic stressors. Understanding the key ecological processes that govern the riverine biota in aquatic ecosystems under multiple pressures has crucial importance. However, there is still insufficient knowledge in quantifying of stressors interactions. Moreover, the understanding of the responses of riverine phytoplankton to multiple stressors is still scarce from catchment aspect. As an interdisciplinary study, the catchment hydrological processes were linked to ecological responses in this study, and we chose phytoplankton functional groups (PFGs) instead of taxonomic classifications of algae to examine their responses to land-use pattern (L), hydrological regime (H), and physicochemical condition (P) across two contrasting hydrological periods (dry, wet). The traits-based phytoplankton functional groups are highly suggested as robust bio-indicators for better understanding the current ecological status. The hydrological regime was described by a matrix indices of hydrological alteration based on the outputs of a well-established ecohydrological model (SWAT). The results from variation partitioning analysis showed that P and H dominate during the dry period and P in high flows. Structural equation models (SEM) showed that the skewness of 7 days discharge emerged as a key driver of H, and had always an indirect effect on functional group TB (benthic diatoms) during both hydrological periods. The functional group M (mainly composed by Microcystis) has directly related to phosphorous in both periods, while indirectly to L of urban area in high flow period, and water bodies in low flow period. This study emphasized that climate change and anthropogenic activities such as altering flow regime and land-use pattern affect directly or indirectly riverine phytoplankton via physicochemical conditions. In addition, our findings

Environment regimes play an important role in structuring trait‐ and taxonomy‐based temporal beta diversity of riverine diatoms

“…Guo et al (2020) calculated short‐period hydrological regime indices (14 and ~28 days before sampling date), and found that these indices override physicochemical variables in structuring riverine diatom traits and community functions. Using structural equation models, Qu et al (2019) observed that the flow regimes (i.e. skewness of 7 days discharge before sampling date) were considered as a key driver for riverine phytoplankton community during two hydrological periods.…”

“…This constraint hinders our inference about the major drivers of community structure to one ‘snapshot’ community, which has missed the temporal variation with different mechanisms. For instance, the role of environmental variables on species composition relies upon the extent of their gradients that might change over time (Qu et al, 2019; Wu et al, 2018). Similarly, the biotic interactions and dispersal could also temporally vary that affect species composition.…”

SER: an R package to compute environmental regime over a certain time period

“…For instance, recent studies found that flow regimes over a short-term period (e.g., 7 or 14 days) played a vital role in riverine algae and biofilm communities (Wu et al . 2018; Qu et al . 2019; Guo et al .…”

“…In addition, different organisms (e.g., algae, macroinvertebrates, fish, macrophytes, or even terrestrial plants) have distinct extent of response to historical environmental regimes. For instance, recent studies found that flow regimes over a short-term period (e.g., 7 or 14 days) played a vital role in riverine algae and biofilm communities (Wu et al 2018;Qu et al 2019;Guo et al 2020;Guo et al 2021). In contrast, macroinvertebrate and fish communities may show a good response to environmental changes over a longer time period (e.g., 4 weeks, 1 year) (Schneider & Petrin 2017).…”

Clasificación de grupos morfofuncionales del fitoplancton en seis sistemas lénticos de las regiones Caribe, Andina y Amazónica de Colombia

“…Las comunidades de fitoplancton son muy diversas y difíciles de predecir en Kruk, et al (2009); constituyen, además, una fuente importante de alimento y un excelente modelo para interpretar procesos ecológicos como la fotosíntesis, la productividad, el ciclo del oxígeno, el carbono y las relaciones asociadas con la transferencia de energía (Hutchinson, 1967;Harris, 1986;Sommer, 1985;Sommer, 2012;Hilton, et al, 2006;Qu, et al, 2019;Ptacnik, et al, 2008;Rousseaux & Gregg, 2014), que se abordan principalmente a partir de la taxonomía, la diversidad del tamaño y la morfología (Huszar & Caraco, 1998;Bonilla, et al, 2005;Borics, et al, 2007;Rosati, et al, 2017).…”