Effects of sample size on estimates of population growth rates calculated with matrix models
Background: Matrix models are widely used to study the dynamics and demography of populations. An important but overlooked issue is how the number of individuals sampled influences estimates of the population growth rate (λ) calculated with matrix models. Even unbiased estimates of vital rates do no...
| Autor principal: | Fiske, Ian J. |
|---|---|
| Outros Autores: | Bruna, Emilio M., Bolker, Benjamin M. |
| Grau: | Artigo |
| Idioma: | English |
| Publicado em: |
PLoS ONE
2020
|
| Assuntos: | |
| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/14735 |
| id |
oai:repositorio:1-14735 |
|---|---|
| recordtype |
dspace |
| spelling |
oai:repositorio:1-14735 Effects of sample size on estimates of population growth rates calculated with matrix models Fiske, Ian J. Bruna, Emilio M. Bolker, Benjamin M. Accuracy Controlled Study Demography Growth Rate Mathematical Computing Mathematical Model Matrix Model Nonhuman Plant Density Population Growth Population Research Population Size Population Structure Sample Size Species Distribution Statistical Analysis Survival Rate Biological Model Classification Cytology Epidemiology Fertility Observer Variation Plant Plant Physiology Population Density Population Dynamics Population Growth Sample Size Statistical Model Demography Fertility Models, Biological Models, Statistical Observer Variation Plant Physiological Phenomena Plants Population Density Population Dynamics Population Growth Sample Size Sampling Studies Background: Matrix models are widely used to study the dynamics and demography of populations. An important but overlooked issue is how the number of individuals sampled influences estimates of the population growth rate (λ) calculated with matrix models. Even unbiased estimates of vital rates do not ensure unbiased estimates of λ-Jensen's Inequality implies that even when the estimates of the vital rates are accurate, small sample sizes lead to biased estimates of λ due to increased sampling variance. We investigated if sampling variability and the distribution of sampling effort among size classes lead to biases in estimates of λ. Methodology/Principal Findings: Using data from a long-term field study of plant demography, we simulated the effects of sampling variance by drawing vital rates and calculating λ for increasingly larger populations drawn from a total population of 3842 plants. We then compared these estimates of λ with those based on the entire population and calculated the resulting bias. Finally, we conducted a review of the literature to determine the sample sizes typically used when parameterizing matrix models used to study plant demography. Conclusions/Significance: We found significant bias at small sample sizes when survival was low (survival=0.5), and that sampling with a more-realistic inverse J-shaped population structure exacerbated this bias. However our simulations also demonstrate that these biases rapidly become negligible with increasing sample sizes or as survival increases. For many of the sample sizes used in demographic studies, matrix models are probably robust to the biases resulting from sampling variance of vital rates. However, this conclusion may depend on the structure of populations or the distribution of sampling effort in ways that are unexplored. We suggest more intensive sampling of populations when individual survival is low and greater sampling of stages with high elasticities. © 2008 Fiske et al. 2020-04-24T17:01:08Z 2020-04-24T17:01:08Z 2008 Artigo https://repositorio.inpa.gov.br/handle/1/14735 10.1371/journal.pone.0003080 en Volume 3, Número 8 Attribution-NonCommercial-NoDerivs 3.0 Brazil http://creativecommons.org/licenses/by-nc-nd/3.0/br/ application/pdf PLoS ONE |
| institution |
Instituto Nacional de Pesquisas da Amazônia - Repositório Institucional |
| collection |
INPA-RI |
| language |
English |
| topic |
Accuracy Controlled Study Demography Growth Rate Mathematical Computing Mathematical Model Matrix Model Nonhuman Plant Density Population Growth Population Research Population Size Population Structure Sample Size Species Distribution Statistical Analysis Survival Rate Biological Model Classification Cytology Epidemiology Fertility Observer Variation Plant Plant Physiology Population Density Population Dynamics Population Growth Sample Size Statistical Model Demography Fertility Models, Biological Models, Statistical Observer Variation Plant Physiological Phenomena Plants Population Density Population Dynamics Population Growth Sample Size Sampling Studies |
| spellingShingle |
Accuracy Controlled Study Demography Growth Rate Mathematical Computing Mathematical Model Matrix Model Nonhuman Plant Density Population Growth Population Research Population Size Population Structure Sample Size Species Distribution Statistical Analysis Survival Rate Biological Model Classification Cytology Epidemiology Fertility Observer Variation Plant Plant Physiology Population Density Population Dynamics Population Growth Sample Size Statistical Model Demography Fertility Models, Biological Models, Statistical Observer Variation Plant Physiological Phenomena Plants Population Density Population Dynamics Population Growth Sample Size Sampling Studies Fiske, Ian J. Effects of sample size on estimates of population growth rates calculated with matrix models |
| topic_facet |
Accuracy Controlled Study Demography Growth Rate Mathematical Computing Mathematical Model Matrix Model Nonhuman Plant Density Population Growth Population Research Population Size Population Structure Sample Size Species Distribution Statistical Analysis Survival Rate Biological Model Classification Cytology Epidemiology Fertility Observer Variation Plant Plant Physiology Population Density Population Dynamics Population Growth Sample Size Statistical Model Demography Fertility Models, Biological Models, Statistical Observer Variation Plant Physiological Phenomena Plants Population Density Population Dynamics Population Growth Sample Size Sampling Studies |
| description |
Background: Matrix models are widely used to study the dynamics and demography of populations. An important but overlooked issue is how the number of individuals sampled influences estimates of the population growth rate (λ) calculated with matrix models. Even unbiased estimates of vital rates do not ensure unbiased estimates of λ-Jensen's Inequality implies that even when the estimates of the vital rates are accurate, small sample sizes lead to biased estimates of λ due to increased sampling variance. We investigated if sampling variability and the distribution of sampling effort among size classes lead to biases in estimates of λ. Methodology/Principal Findings: Using data from a long-term field study of plant demography, we simulated the effects of sampling variance by drawing vital rates and calculating λ for increasingly larger populations drawn from a total population of 3842 plants. We then compared these estimates of λ with those based on the entire population and calculated the resulting bias. Finally, we conducted a review of the literature to determine the sample sizes typically used when parameterizing matrix models used to study plant demography. Conclusions/Significance: We found significant bias at small sample sizes when survival was low (survival=0.5), and that sampling with a more-realistic inverse J-shaped population structure exacerbated this bias. However our simulations also demonstrate that these biases rapidly become negligible with increasing sample sizes or as survival increases. For many of the sample sizes used in demographic studies, matrix models are probably robust to the biases resulting from sampling variance of vital rates. However, this conclusion may depend on the structure of populations or the distribution of sampling effort in ways that are unexplored. We suggest more intensive sampling of populations when individual survival is low and greater sampling of stages with high elasticities. © 2008 Fiske et al. |
| format |
Artigo |
| author |
Fiske, Ian J. |
| author2 |
Bruna, Emilio M. Bolker, Benjamin M. |
| author2Str |
Bruna, Emilio M. Bolker, Benjamin M. |
| title |
Effects of sample size on estimates of population growth rates calculated with matrix models |
| title_short |
Effects of sample size on estimates of population growth rates calculated with matrix models |
| title_full |
Effects of sample size on estimates of population growth rates calculated with matrix models |
| title_fullStr |
Effects of sample size on estimates of population growth rates calculated with matrix models |
| title_full_unstemmed |
Effects of sample size on estimates of population growth rates calculated with matrix models |
| title_sort |
effects of sample size on estimates of population growth rates calculated with matrix models |
| publisher |
PLoS ONE |
| publishDate |
2020 |
| url |
https://repositorio.inpa.gov.br/handle/1/14735 |
| _version_ |
1787141302188507136 |
| score |
11.675608 |