Estimation of Vital Rates and Age Distribution Under Quasi-Stability: Case of India, 1961, Reexamined

1977 ◽  
Vol 43 (2) ◽  
pp. 187
Author(s):  
P. N. Mari Bhat
Keyword(s):  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jeffrey A. Hostetler ◽  
Julien Martin ◽  
Michael Kosempa ◽  
Holly H. Edwards ◽  
Kari A. Rood ◽  
...  

AbstractModels of marine mammal population dynamics have been used extensively to predict abundance. A less common application of these models is to reconstruct historical population dynamics, filling in gaps in observation data by integrating information from multiple sources. We developed an integrated population model for the Florida manatee (Trichechus manatus latirostris) to reconstruct its population dynamics in the southwest region of the state over the past 20 years. Our model improved precision of key parameter estimates and permitted inference on poorly known parameters. Population growth was slow (averaging 1.02; 95% credible interval 1.01–1.03) but not steady, and an unusual mortality event in 2013 led to an estimated net loss of 332 (217–466) manatees. Our analyses showed that precise estimates of abundance could be derived from estimates of vital rates and a few input estimates of abundance, which may mean costly surveys to estimate abundance don’t need to be conducted as frequently. Our study also shows that retrospective analyses can be useful to: (1) model the transient dynamics of age distribution; (2) assess and communicate the conservation status of wild populations; and (3) improve our understanding of environmental effects on population dynamics and thus enhance our ability to forecast.


2014 ◽  
Vol 41 (1-2) ◽  
pp. 1
Author(s):  
Barry Edmonston

One key aspect of the demographic transition—the shift from high mortality and high fertility to low mortality and low fertility is a major change in the population’s age distribution from a pyramid-shaped young age structure to a pillar-shaped old age structure. This paper discusses two demographic processes affected by changes in age structure. First, there are effects on vital rates, with important differences in the observed crude rates and the implied intrinsic vital rates. Second, changes in age structure influence population momentum. More recently, demographers have noted that older age distributions associated with fertility levels below replacement have negative population momentum. Although the demographic transition has been well-described for many countries, demographers have seldom analyzed intrinsic vital rates and population momentum over time, which are dynamic processes affected by changes in the population age structure and which, in turn, influence future changes in population growth and size. This paper uses new data and methods to analyze intrinsic vital rates and population momentum across two centuries of demographic change in Canada 


1996 ◽  
Vol 11 (3) ◽  
pp. 284-290 ◽  
Author(s):  
N. S. Losure ◽  
K. Jayaraman ◽  
C. A. Petty

2013 ◽  
Vol 32 (4) ◽  
pp. 368-373
Author(s):  
Rong LIANG ◽  
En-da YU ◽  
Wei ZHU ◽  
Jie GAO ◽  
Zhao-shen LI ◽  
...  

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