Factors modulating herbivory patterns in Cymodocea nodosa meadows

Abstract

In coastal marine food webs, seagrass‐grazer interactions play a fundamental role in ecological processes by regulating the structure and functioning of plant communities. Therefore, assessing the strength of these seagrass‐grazer links and identifying the mechanisms that regulate these relationships are crucial to increasing our understanding of community and ecosystem structure and dynamics. Herbivory on the temperate seagrass Cymodocea nodosa was evaluated in four locations with contrasting abiotic and biotic factors (i.e., depth; meadow size; seagrass shoot density, productivity, and leaf traits; and herbivore presence) using cross‐transplantation experiments carried out once per season to account for seasonal variation. Patterns of feeding rates on C. nodosa meadows showed high temporal variability, with peaks occurring in spring and summer. Results indicate that between 46.59% and 74.08% of the annual leaf production is lost to herbivory at the locations sampled in this study. Herbivory rates increased with higher nitrogen content and shoot density for all types of consumers (mesograzers, fishes, and sea urchins). This work highlights the need to integrate the abiotic and biotic factors modulating herbivory patterns, particularly in a foundation species like C. nodosa, for which changes in plant traits and grazer abundance may trigger trophic cascades with far‐reaching consequences for associated species.

Effect of marine heat waves on carbon metabolism, optical characterization, and bioavailability of dissolved organic carbon in coastal vegetated communities

“…In the water column, nutrient peaks usually occur in winter, with values up to 1.4 μ mol L −1 , 12 μ mol L −1 , 25 μ mol L −1 , and 1.5 μ mol L −1 (Tovar et al 2000). For detailed information of the study area, see previous descriptions in Jiménez‐Ramos et al (2021) and Peralta et al (2021).…”

“…Marine heatwaves are usually defined as a prolonged, discrete, anomalously warm water event that can be described by its duration (at least 3 d) and intensity (warmer than the 90 th percentile of the local long‐term climatological observations; typically at least 2°C) and that can occur throughout the year, even in winter (Hobday et al 2016; Oliver et al 2019). Seagrasses and benthic macroalgae are considered ecosystem engineers who provide a large number of ecological functions and services, including, for example, shoreline protection, suitable breeding habitats, biodiversity hotspots, and carbon sequestration (Campagne et al 2015; Jiménez‐Ramos et al 2021). In recent years, the effect of sudden and temporary temperature increases, such as marine heatwaves, on these communities has been assessed.…”

Wave, light, and dissolved oxygen exposures drive novel coastal eelgrass (Zostera pacifica) transplant performance

“…Seagrass spatial coverage and habitat function are controlled by complex abiotic and biotic environmental factors (Munsch et al, 2023). Biological top-down controls can positively impact seagrass health (Hughes et al, 2013;Foster et al, 2021), or as is the case with herbivory, cause direct consumptive loss to the seagrass bed (Altstatt, 2003;Heck and Valentine, 2006;Jimeńez-Ramos et al, 2021;Valentine and Heck, 2021). High ocean temperatures can change photosynthetic efficiencies, deteriorate disease resistance, alter community structure, and reduce growth and survival of seagrasses growing near species-specific thermal tolerances (Johnson et al, 2003;York et al, 2013;Moore et al, 2014;Jakobsson-Thor et al, 2020;Strydom et al, 2020).…”