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Variability in space use among conspecifics can emerge from foraging strategies that track available resources, especially in riverscapes that promote high synchrony between prey pulses and consumers. Projected changes in riverscape hydrological regimes due to water management and climate change accentuate the need to understand the natural variability in animal space use and its implications for population dynamics and ecosystem function. Here, we used long-term tracking of Common Snook (Centropomus undecimalis) movement and trophic dynamics in the Shark River, Everglades National Park from 2012 to 2023 to test how specialization in the space use of individuals (i.e., Eadj) changes seasonally, how it is influenced by yearly hydrological conditions, and its relationship to the between individual trophic niche. Snook exhibited seasonal variability in space use, with maximum individual specialization (high dissimilarity) in the wet season. The degree of individual specialization increased over the years in association with greater marsh flooding duration, which produced important subsidies. Also, there were threshold responses of individual space use specialization as a function of floodplain conditions. Greater specialization in space use results in a decrease in snook trophic niche size. These results show how hydrological regimes in riverscapes influence individual specialization of resource use (both space and prey), providing insight into how forecasted hydroclimatic scenarios may shape habitat selection processes and the trophic dynamics of mobile consumers.
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The effects of temperature and flooding duration on the structure and magnitude of a floodplain prey subsidy
Abstract Riverine floodplains serve as an important link between terrestrial and aquatic systems, as the rising and falling of water drive spatial food web subsidies that are critical to the functioning and stability of ecosystems. As these systems are increasingly impacted by hydrological alterations and climate change, it is important to understand how floodplain spatial food web subsidies may respond to changing environmental conditions.Here, we examine the interannual variation in the structure of a sunfish (Lepomisspp.) prey subsidy from freshwater marshes into the mangrove‐lined creeks of Rookery Branch in the Florida Coastal Everglades that occurs during seasonal dry downs. We evaluate how the structure of this subsidy relates to prior temperature and hydrological regimes based on a 16‐year electrofishing dataset. We also characterise the intra‐annual relationship between marsh water depths and sunfish migration patterns that underlie this subsidy.We found that interannual variation in the abundance and diversity of the sunfish prey subsidy was best explained by the minimum water temperature occurring within 90 days prior to peak abundance sampling periods, with lower minimum water temperatures associated with higher sunfish abundance and diversity. In contrast, interannual variations in the biomass of the sunfish prey subsidy were positively related to marsh flooding duration over 30 cm depth during the prior wet season. Intra‐annual models estimated peak sunfish abundance and biomass values in riverine habitats to occur during the transition between wet and dry periods when marsh depths are between 10 and 15 cm.Multivariate analysis of community abundance and biomass composition revealed that minimum water temperatures played an important role in structuring the prey subsidy, while the effect of flooding duration was weak. These results provide important insight into how floodplain prey subsidies may be altered under future climate and hydrological regimes and inform ecosystem‐based water management decisions.
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- PAR ID:
- 10468733
- Publisher / Repository:
- Wiley Online LIbrary
- Date Published:
- Journal Name:
- Freshwater Biology
- Volume:
- 68
- Issue:
- 9
- ISSN:
- 0046-5070
- Page Range / eLocation ID:
- 1518-529
- Subject(s) / Keyword(s):
- Everglades floodplain Lepomis marsh spatial subsidy sunfish
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1111/fwb.14145
