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Coastal wetlands display ecohydrological zonation such that vertical differences of plant zones are driven by varying groundwater levels over tidal cycles. It is unclear how variable levels of tidal drainage directly impact biotic and abiotic factors in coastal wetland ecosystems. To determine the impacts of drainage levels, simulated tides in mesocosms with varying degrees of drainage were created with Spartina alterniflora, the salt marsh coastal ecosystem dominant species on the United States Atlantic Coast, and Salicornia pacifica, the Pacific Coast dominant. We measured biomass production and photosynthesis as indicators of plant health, and we also measured soil and porewater characteristics to help interpret patterns of productivity. These measures included above and belowground biomass, porewater pH, salinity, ammonium concentration, sulfide concentration, soil redox potential, net ecosystem exchange, photosynthesis rate, respiration rate, and methane flux. We found the greatest plant production in soils with intermediate drainage levels, with production values that were 13.7% higher for S. alterniflora and 57.7% higher for S. pacifica in the intermediate flooding levels than found in more inundated and more drained conditions. Understanding how drainage impacts plant species is important for predicting wetland resilience to sea level rise, as increasing water levels alter ecohydrological zonation.
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This content will become publicly available on April 1, 2026
Resilience at the Cost of Productivity: Biological Soil Crusts Mediate Vegetation Spatial Self‐Organization in Drylands
ABSTRACT Water redistribution during rain events in drylands plays a critical role in the persistence and spatial pattern of vascular plants in these patchy ecosystems. Biological soil crusts (BSCs) form a membrane in the soil surface and mediate ecohydrological dynamics. However, little is known about their influence on dryland ecosystem state and spatial pattern under changing climate, which may alter total annual rainfall and intraannual rainfall regime. Building on existing models, we develop a model that considers BSC–vascular plant interactions and realistic ecohydrological dynamics under rainfall pulses. We find that the presence of BSCs often increases ecosystem resilience by promoting runoff to plants under high aridity. However, the benefit of BSCs comes at the cost of plant biomass under relatively wetter conditions; a threshold in BSC effect occurs when water losses from BSCs exceed the benefit by their surface water routing to plants. Increased resilience from BSCs, and their own persistence, can be promoted in finer soils and under rainfall regimes of less frequent events—projected for many drylands. Lastly, we find that BSCs alter feedbacks underlying plant spatial self‐organization and hence their formed patterns. In high aridity, BSCs likely ameliorate competition between plants through large scale runoff promotion, reducing plant spatial pattern regularity. Our analysis highlights that BSCs significantly shape drylands' response to climate change and their positive effects on resilience may be stronger and more pervasive in a drier future, but such benefits come at a cost of ecosystem biomass and productivity when aridity is outside a critical range.
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- Award ID(s):
- 2320296
- PAR ID:
- 10635455
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Ecohydrology
- Volume:
- 18
- Issue:
- 3
- ISSN:
- 1936-0584
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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