The consequences of the variancemean rescaling effect on effective population size
(2007) In Oikos 116(5). p.769774 Abstract
 The effective population size (Ne), and the ratio between Ne and census population size (N) are often used as measures of population viability. We show that using the harmonic mean of population sizes over time  a common proxy for Ne has some important evolutionary consequences and implications for conservation management. This stems from the fact that there is no unambiguous relationship between the arithmetic and harmonic means for populations fluctuating in size. As long as the variance of population size increases moderately with increasing arithmetic mean population size, the harmonic mean also increases. However, if the variance of population size increases more rapidly, which existing data often suggest, then the harmonic mean... (More)
 The effective population size (Ne), and the ratio between Ne and census population size (N) are often used as measures of population viability. We show that using the harmonic mean of population sizes over time  a common proxy for Ne has some important evolutionary consequences and implications for conservation management. This stems from the fact that there is no unambiguous relationship between the arithmetic and harmonic means for populations fluctuating in size. As long as the variance of population size increases moderately with increasing arithmetic mean population size, the harmonic mean also increases. However, if the variance of population size increases more rapidly, which existing data often suggest, then the harmonic mean may actually decrease with increasing arithmetic mean. Thus maximizing N may not maximize Ne,N but could instead lower the adaptive potential and hence limit the evolutionary response to environmental change. Large census size has the clear advantage of lowering demographic stochasticity, and hence extinction risk, and under certain conditions large census size also minimizes the loss of genetic variation. Consequently, maximising census size has served as a useful dogma in ecology, genetics and conservation. Nonetheless, due to the intricate relationships among Ne, population viability and the properties of population fluctuations, we suggest that this dogma should be taken only as a rule of thumb. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/record/168665
 author
 Pertoldi, C; Bach, Lars ^{LU} ; Barker, J S F; Lundberg, Per ^{LU} and Loeschcke, V
 organization
 publishing date
 2007
 type
 Contribution to journal
 publication status
 published
 subject
 in
 Oikos
 volume
 116
 issue
 5
 pages
 769  774
 publisher
 WileyBlackwell
 external identifiers

 wos:000245814500006
 scopus:34247394691
 ISSN
 16000706
 DOI
 10.1111/j.00301299.2007.15672.x
 language
 English
 LU publication?
 yes
 id
 396738c0178e4c0180b8501f599963b9 (old id 168665)
 date added to LUP
 20070703 15:03:05
 date last changed
 20180107 05:20:48
@article{396738c0178e4c0180b8501f599963b9, abstract = {The effective population size (Ne), and the ratio between Ne and census population size (N) are often used as measures of population viability. We show that using the harmonic mean of population sizes over time  a common proxy for Ne has some important evolutionary consequences and implications for conservation management. This stems from the fact that there is no unambiguous relationship between the arithmetic and harmonic means for populations fluctuating in size. As long as the variance of population size increases moderately with increasing arithmetic mean population size, the harmonic mean also increases. However, if the variance of population size increases more rapidly, which existing data often suggest, then the harmonic mean may actually decrease with increasing arithmetic mean. Thus maximizing N may not maximize Ne,N but could instead lower the adaptive potential and hence limit the evolutionary response to environmental change. Large census size has the clear advantage of lowering demographic stochasticity, and hence extinction risk, and under certain conditions large census size also minimizes the loss of genetic variation. Consequently, maximising census size has served as a useful dogma in ecology, genetics and conservation. Nonetheless, due to the intricate relationships among Ne, population viability and the properties of population fluctuations, we suggest that this dogma should be taken only as a rule of thumb.}, author = {Pertoldi, C and Bach, Lars and Barker, J S F and Lundberg, Per and Loeschcke, V}, issn = {16000706}, language = {eng}, number = {5}, pages = {769774}, publisher = {WileyBlackwell}, series = {Oikos}, title = {The consequences of the variancemean rescaling effect on effective population size}, url = {http://dx.doi.org/10.1111/j.00301299.2007.15672.x}, volume = {116}, year = {2007}, }