Density-Dependent Interactions BetweenHydrilla verticillata(L.F.) Royle and Phytoplankton: A Mesocosm Experiment

2014 ◽  
Vol 43 (12) ◽  
pp. 1623-1632 ◽  
Author(s):  
Hao Jiang ◽  
Dehua Zhao ◽  
Hui Zhao ◽  
Ying Cai ◽  
Delin Xu ◽  
...  
Keyword(s):  
Mesocosm Experiment ◽  
Density Dependent

Nutrient loading by anadromous alewife (Alosa pseudoharengus): contemporary patterns and predictions for restoration efforts

2010 ◽  
Vol 67 (8) ◽  
pp. 1211-1220 ◽  
Author(s):  
Derek C. West ◽  
Annika W. Walters ◽  
Stephen Gephard ◽  
David M. Post
Keyword(s):  
Nutrient Loading ◽  
Mesocosm Experiment ◽  
Alosa Pseudoharengus ◽  
Nutrient Budgets ◽  
Freshwater Lakes ◽  
Phosphorus Load ◽  
Coastal Lakes ◽  
Density Dependent ◽  
Early Survival ◽  
The 1960S

Anadromous alewives ( Alosa pseudoharengus ) have the potential to alter the nutrient budgets of coastal lakes as they migrate into freshwater as adults and to sea as juveniles. Alewife runs are generally a source of nutrients to the freshwater lakes in which they spawn, but juveniles may export more nutrients than adults import in newly restored populations. A healthy run of alewives in Connecticut imports substantial quantities of phosphorus; mortality of alewives contributes 0.68 g P·fish–1, while surviving fish add 0.18 g P, 67% of which is excretion. Currently, alewives contribute 23% of the annual phosphorus load to Bride Lake, but this input was much greater historically, with larger runs of bigger fish contributing 2.5 times more phosphorus in the 1960s. A mesocosm experiment in a nearby lake showed that juvenile alewife growth is strongly density dependent, but early survival may be too low for juvenile outmigration to balance adult inputs. In eutrophic systems where nutrients are a concern, managers can limit nutrient loading by capping adult returns at a level where juvenile populations would not be suppressed.

Urbanization impacts on production and recruitment of Fundulus heteroclitus in salt marsh creeks

2020 ◽  
Vol 645 ◽  
pp. 187-204
Author(s):  
PJ Rudershausen ◽  
JA Buckel
Keyword(s):  
Salt Marsh ◽  
Salt Marshes ◽  
Fundulus Heteroclitus ◽  
Multiple Factor Analysis ◽  
Southeastern Usa ◽  
Density Dependent ◽  
Dependent Relationship ◽  
Juvenile Abundance ◽  
The Relationship ◽  
Throw Trap

It is unclear how urbanization affects secondary biological production in estuaries in the southeastern USA. We estimated production of larval/juvenile Fundulus heteroclitus in salt marsh areas of North Carolina tidal creeks and tested for factors influencing production. F. heteroclitus were collected with a throw trap in salt marshes of 5 creeks subjected to a range of urbanization intensities. Multiple factor analysis (MFA) was used to reduce dimensionality of habitat and urbanization effects in the creeks and their watersheds. Production was then related to the first 2 dimensions of the MFA, month, and year. Lastly, we determined the relationship between creek-wide larval/juvenile production and abundance from spring and abundance of adults from autumn of the same year. Production in marsh (g m-2 d-1) varied between years and was negatively related to the MFA dimension that indexed salt marsh; higher rates of production were related to creeks with higher percentages of marsh. An asymptotic relationship was found between abundance of adults and creek-wide production of larvae/juveniles and an even stronger density-dependent relationship was found between abundance of adults and creek-wide larval/juvenile abundance. Results demonstrate (1) the ability of F. heteroclitus to maintain production within salt marsh in creeks with a lesser percentage of marsh as long as this habitat is not removed altogether and (2) a density-dependent link between age-0 production/abundance and subsequent adult recruitment. Given the relationship between production and marsh area, natural resource agencies should consider impacts of development on production when permitting construction in the southeastern USA.

Sign in / Sign up

Export Citation Format

Share Document