Size-specific sensitivity of cladocerans to freshwater salinization: Evidences from the changes in life history and population dynamics

2022 ◽  
Vol 296 ◽  
pp. 118770
Author(s):  
Jing Huang ◽  
Yurou Li ◽  
Yunfei Sun ◽  
Lu Zhang ◽  
Kai Lyu ◽  
...  
Crustaceana ◽  
2021 ◽  
Vol 94 (4) ◽  
pp. 413-429
Author(s):  
Ye Ji Lee ◽  
Won Gyu Park

Abstract The population dynamics of Stenothoe valida Dana, 1852 were studied at Cheongsapo beach of Busan, Republic of Korea, from March 2019 to March 2020. Sampling was conducted once a month at low tide during spring tides. Specimens were grouped by the cephalic length at 0.025 mm intervals, and classified into four categories: females, ovigerous females, males and juveniles. The sex ratio, defined as females : total males + females, exceeded 0.5 during most of the study period. Brood size was significantly coupled with ovigerous female size. Two to four cohorts appeared at each study period. New cohorts occurred at almost every sampling except in the samples Jun-2, and Nov-2. Life span was estimated at 1-2 months. The juvenile ratio, the ratio of ovigerous females, and the recruitment rate estimated by FiSAT were commonly high in summer and winter. The life history of S. valida was not coupled with water temperature, but had a strong seasonal pattern.


2006 ◽  
Vol 58 (4) ◽  
pp. 562-566 ◽  
Author(s):  
C. Reigada ◽  
W.A.C. Godoy

The effect of larval density on the survival, fecundity and body size at two temperatures in experimental populations of C. megacephala was studied. No effect from simultaneous influence of density and temperature on life history characteristics of C. megacephala was found. Significant effects of density and temperature on survival, fecundity and body size were observed. The importance of these results for the population dynamics of C. megacephala is discussed.


2014 ◽  
Vol 71 (8) ◽  
pp. 1198-1208 ◽  
Author(s):  
Douglas C. Braun ◽  
John D. Reynolds

Understanding linkages among life history traits, the environment, and population dynamics is a central goal in ecology. We compared 15 populations of sockeye salmon (Oncorhynchus nerka) to test general hypotheses for the relative importance of life history traits and environmental conditions in explaining variation in population dynamics. We used life history traits and habitat variables as covariates in mixed-effect Ricker models to evaluate the support for correlates of maximum population growth rates, density dependence, and variability in dynamics among populations. We found dramatic differences in the dynamics of populations that spawn in a small geographical area. These differences among populations were related to variation in habitats but not life history traits. Populations that spawned in deep water had higher and less variable population growth rates, and populations inhabiting streams with larger gravels experienced stronger negative density dependence. These results demonstrate, in these populations, the relative importance of environmental conditions and life histories in explaining population dynamics, which is rarely possible for multiple populations of the same species. Furthermore, they suggest that local habitat variables are important for the assessment of population status, especially when multiple populations with different dynamics are managed as aggregates.


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