Changing phenology of benthic primary producers in inland waters: Current knowledge and future directions

Benthic primary producers (BPP) in inland waters, including aquatic macrophytes and periphyton, are foundational habitats that are highly sensitive to multiple human drivers of environmental change. However, long-term seasonal monitoring of BPP is limited, leaving us with little information on the cause, directionality, and consequences of the potential shifts in timing of BPP life cycle events. Here, we review the literature on the phenological changes of BPP and show that BPP respond primarily to temperature, but also to other interactive drivers related to climate change and eutrophication. In addition, we present four rare case studies where BPP display strong and earlier shifts in event timing associated with increasing temperature and discuss potential impacts of these changes on ecosystem functioning. Given the responsive nature of BPP to multiple human drivers, we provide suggestions on how to improve basic monitoring to better understand the future impact of phenological changes of this critical habitat.