Human Actions Alter Tidal Marsh Seascapes and the Provision of Ecosystem Services

Abstract

Tidal marshes are a key component of coastal seascape mosaics that support a suite of socially and economically valuable ecosystem services, including recreational opportunities (e.g., fishing, birdwatching), habitat for fisheries species, improved water quality, and shoreline protection. The capacity for tidal marshes to support these services is, however, threatened by increasingly widespread human impacts that reduce the extent and condition of tidal marshes across multiple spatial scales and that vary substantially through time. Climate change causes species redistribution at continental scales, changes in weather patterns (e.g., rainfall), and a worsening of the effect of coastal squeeze through sea level rise. Simultaneously, the effects of urbanization such as habitat loss, eutrophication, fishing, and the spread of invasive species interact with each other, and with climate change, to fundamentally change the structure and functioning of tidal marshes and their food webs. These changes affect tidal marshes at local scales through changes in plant community composition, complexity, and condition and at regional scales through changes in habitat extent, configuration, and connectivity. However, research into the full effects of these multi-scaled, interactive stressors on ecosystem service provision in tidal marshes is in its infancy and is somewhat geographically restricted. This hinders our capacity to quickly and effectively curb loss and degradation of both tidal marshes and the services they deliver with targeted management actions. We highlight ten priority research questions seeking to quantify the consequences and scales of human impacts on tidal marshes that should be answered to improve management and restoration plans.

Seascape ecology: identifying research priorities for an emerging ocean sustainability science

“…Integrating behavioural responses to spatial patterns into spatial models, such as in individualbased models (Stillman et al 2015, Hovel & Regan 2018, and increased performance of multi-scale predictive mapping (Pittman & Brown 2011, Hattab et al 2014, McGarigal et al 2016) will help reduce uncertainty in our efforts to explain and forecast the ecological consequences of seascape shifts under a changing climate. For example, linking the patterns of structural change in habitat to ecological processes such as predator−prey dynamics and the implications for food web structure can inform management decisions (Gilby et al 2020b). For the open ocean, the merging of hierarchy theory and patch dynamics with oceanographic and ecological paradigms provides an ecological framework with implications for advancing dynamic ocean management for sustainable fisheries and biodiversity conservation (Hidalgo et al 2016, Kavanaugh et al 2016), which will be a valuable management approach as species' ranges continue to shift.…”

Climate Change Implications for Tidal Marshes and Food Web Linkages to Estuarine and Coastal Nekton

“…Tidal marshes are vegetated intertidal habitats that occur at the land-sea interface and thus serve as critical transition zones linking marine, freshwater, and terrestrial processes (Boström et al 2011). Recent research demonstrates the urgent need to understand both short-and long-term impacts of climate change and sea level rise (SLR) on tidal marsh ecosystem function, food webs, and fisheries support (Able this issue;Baker et al 2020;Gilby et al 2020). The cumulative impacts of multiple interacting stressors, and whether the net effects are additive, synergistic, or antagonistic, are receiving increased attention in the ecological literature (Crain et al 2008;Przeslawski et al 2015;Jackson et al 2016;Lauchlan and Nagelkerken 2020).…”

“…While coastal and estuarine ecosystems can resist and recover from minor to moderate natural disturbances, multiple stressors interacting synergistically, whereby the combined effects are greater than the sum of the individual (additive) effects, may lead to novel ecological responses (Crain et al 2008;Jackson et al 2016) or exceed critical ecological thresholds that result in fundamental state changes (Boström et al 2011). Quantifying the combined effects of climate-related stressors on costal and estuarine nekton, and their associated fisheries, is of great conservation, restoration, and socio-economic concern (zu Ermgassen et al this issue;Waltham et al 2021;Baker et al 2020;Gilby et al 2020). Yet disentangling the drivers of change and ecological outcomes remains a major challenge to researchers and managers.…”

“…Climate change interactions with anthropogenic drivers of seascape change(Gilby et al 2020) & Geographic variation in climate change impacts on tidal marsh structure and function(Ziegler et al 2021) & Strategies to mitigate the effects of climate change and urbanization through restoration techniques(Waltham et al 2021) …”

Changes in Trophic Structure of An Exploited Fish Community At The Centennial Scale Are Linked To Fisheries and Climate Forces

“…Examples from natural systems are rare but are essential if we are to understand the broader implications of natural processes and human activities for marine food webs 17 . For instance, overexploitation and ocean warming have had increasing influences on marine communities and ecosystem function over the last century 7,18,19 , with cumulative impacts observed across more than half of the global ocean 20 . In this context, long-term studies that incorporate archival samples to measure changes in trophic structure can provide important new insights into how the relatively recent history of human impacts have modified natural marine food webs [21][22][23] .…”