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Numerous species face redistribution and compression of habitat due to climate change. Compounded with anthropogenic stressors, coastal systems are among those experiencing the largest shifts in distribution and degradation of habitats. We coupled long-term movement and environmental data to assess how a freshwater species responds to changes in a coastal refuge habitat to quantify distributional changes, identify key environmental variables, and provide restoration targets. Salinity, variation in salinity, and stage of surrounding marsh habitat were the most important variables driving Florida bass (Micropterus salmoides) occurrence in the estuary. Salinity below 8.7 ppt had the largest positive effect on Florida bass occurrence, while low levels of daily variation in salinity (< 1.3 SD) and marsh stages between 11.4 and 27.7 cm were associated with an increased probability of Florida bass occurrence. Years with above average freshwater inputs that shifted mesohaline boundaries downstream generated 15.3 km2 of both core and conditional habitat for Florida bass, average conditions generated 4.4 km2 of core and conditional habitat, whereas dry conditions compressed Florida bass habitat to 1.7 km2. These results suggest that varying environmental scenarios can shift the amount of suitable habitat available for freshwater species using conditional coastal habitats. Our study provides salinity and marsh depth thresholds that offer actionable management targets to maximize the presence of Florida bass in coastal rivers, with population and fishing quality benefits. Climate change will likely result in large-scale reductions of critical dry season habitat for these species, while restoration efforts and adaptive management can bolster the resiliency of these habitats.
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Optimal Planting Distance in a Simple Model of Habitat Restoration With an Allee Effect
Ecological restoration is emerging as an important strategy to improve the recovery of degraded lands and to combat habitat and biodiversity loss worldwide. One central unresolved question revolves around the optimal spatial design for outplanted propagules that maximizes restoration success. Essentially, two contrasting paradigms exist: the first aims to plant propagules in dispersed arrangements to minimize competitive interactions. In contrast, ecological theory and recent field experiments emphasize the importance of positive species interactions, suggesting instead clumped planting configurations. However, planting too many propagules too closely is likely to waste restoration resources as larger clumps have less edges and have relatively lower spread rates. Thus, given the constraint of limited restoration efforts, there should be an optimal planting distance that both is able to harness positive species interactions but at the same time maximizes spread in the treated area. To explore these ideas, here we propose a simple mathematical model that tests the influence of positive species interactions on the optimal design of restoration efforts. We model the growth and spatial spread of a population starting from different initial conditions that represent either clumped or dispersed configurations of planted habitat patches in bare substrate. We measure the spatio-temporal development of the population, its relative and absolute growth rates as well as the time-discounted population size and its dependence on the presence of an Allee effect. Finally, we assess whether clumped or dispersed configurations perform better in our models and qualitatively compare the simulation outcomes with a recent wetland restoration experiment in a coastal wetland. Our study shows that intermediate clumping is likely to maximize plant spread under medium and high stress conditions (high occurrence of positive interactions) while dispersed designs maximize growth under low stress conditions where competitive interactions dominate. These results highlight the value of mathematical modeling for optimizing the efficiency of restoration efforts and call for integration of this theory into practice.
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- Award ID(s):
- 1832178
- PAR ID:
- 10312735
- Date Published:
- Journal Name:
- Frontiers in Marine Science
- Volume:
- 7
- ISSN:
- 2296-7745
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3389/fmars.2020.610412
