Symbols. Defmitions. and Units
113
A parameter sensitivity analysis revealed that all the investigated population properties were most sensitive to parameters associated with the
efficiency of food collection and food utilization. By comparison, typical
life-history parameters, including egg/neonate size, size at first reproductive investment and maximum reproductive investment, had only minor
influence on population performance. The sensitivities to size- or agedependent parameter variations were small for most population performance measures. This might be taken as an argument for using a simple, unstructured population model as an approximation to the dynamics of
Daphnia populations under certain circumstances.
4.9 Symbols, Definitions, and Units
Symbol Definition
Dimension
a
Fraction of cohort developing from aberrant eggs
f3
Asymptotic, population specific birth rate
day"1
B
Body size
IlgC
Bo
Egg size
IlgC
B,
Neonate body size
IlgC
Bi
Body size at the start of instar i
IlgC
B'
Body size at first reproductive investment
IlgC
B"
Body size at first maternity
IlgC
B'"
Maximum body size
IlgC
B ..
Extrapolated body size where net assimilation is zero
IlgC
B' ..
Extrapolated body size where ingestion is zero
IlgC
C
Food carbon concentration
(mgC)r l
C'
Incipient limiting food concentration
(mgC)r l
C"
Threshold food level for positive individual growth
(mgC)r l
C' 1
Threshold food level for positive neonate growth
(mgC)r l
C" /I
Threshold food level for reproduction
(mgC)r l
C"A
Threshold food level for positive netpopulation growth
(mgC)r l
Di
Duration of instar i
days