Influence of water quality on the macroinvertebrate community in a tropical estuary (Buenaventura Bay)

Spatiotemporal patterns of trophic niche variation within and among species of tropical coastal fishes

Intraspecific niche variation shapes the structure and function of food webs, but we still know little about the magnitude and drivers of trophic variation within species in species‐rich communities. Here, we examined how intrinsic (sex and life stage) and extrinsic (locality and season) factors affect the diet composition and trophic niche width of tropical fish species. Specifically, we studied co‐occurring species with benthopelagic (Stellifer ericymba, S. melanocheir, S. zestocarus, and Larimus argenteus) and benthic feeding habits (S. strabo, Cathorops manglarensis, Notarius troschelii, and Urotrygon rogersi) on the central Pacific coast of Colombia. Overall, we observed strong spatial and seasonal effects driving variation in the consumption of (i) amphipods, copepods, and decapods for benthopelagic species and (ii) mollusks and polychaetes for benthic species. As expected, we observed little sexual diet variation; however, surprisingly, most species showed little ontogenetic diet variation. Seasonality strongly shaped the trophic niche width for most species, but effects were species‐specific, suggesting no general pattern of seasonal niche expansion across species. In turn, spatial effects on the trophic niche width were congruent across species, which might be related to differences in the diversity of available resources between bays. Our results reveal the complex interplay between intrinsic and extrinsic factors in shaping resource exploitation by coastal fish. This high level of trophic plasticity may be a critical component for both the persistence of marine populations and the stability of local food webs.

Abstract in Spanish is available with online material.

Marine macroinvertebrate ecosystem services under changing conditions of seagrasses and mangroves

This study aimed to investigate the impact of changing environmental conditions on MMI ES in seagrasses and mangroves. We used data from satellite and biodiversity platforms combined with field data to explore the links between ecosystem pressures (habitat conversion, overexploitation, climate change), conditions (environmental quality, ecosystem attributes), and MMI ES (provisioning, regulation, cultural). Both seagrass and mangrove extents increased significantly since 2016. While sea surface temperature showed no significant annual variation, sea surface partial pressure CO2, height above sea level and pH presented significant changes. Among the environmental quality variables only silicate, PO4 and phytoplankton showed significant annual varying trends. The MMI food provisioning increased significantly, indicating overexploitation that needs urgent attention. MMI regulation and cultural ES did not show significant trends overtime. Our results show that MMI ES are affected by multiple factors and their interactions can be complex and non-linear. We identified key research gaps and suggested future directions for research. We also provided relevant data that can support future ES assessments.