### Abstract

A key challenge in the estimation of tropical arthropod species richness is the appropriate management of the large uncertainties associated with any model. Such uncertainties had largely been ignored until recently, when we attempted to account for uncertainty associated with model variables, using Monte Carlo analysis. This model is restricted by various assumptions. Here, we use a technique known as probability bounds analysis to assess the influence of assumptions about (1) distributional form and (2) dependencies between variables, and to construct probability bounds around the original model prediction distribution. The original Monte Carlo model yielded a median estimate of 6. 1 million species, with a 90 % confidence interval of [3. 6, 11. 4]. Here we found that the probability bounds (p-bounds) surrounding this cumulative distribution were very broad, owing to uncertainties in distributional form and dependencies between variables. Replacing the implicit assumption of pure statistical independence between variables in the model with no dependency assumptions resulted in lower and upper p-bounds at 0. 5 cumulative probability (i. e., at the median estimate) of 2. 9-12. 7 million. From here, replacing probability distributions with probability boxes, which represent classes of distributions, led to even wider bounds (2. 4-20. 0 million at 0. 5 cumulative probability). Even the 100th percentile of the uppermost bound produced (i. e., the absolutely most conservative scenario) did not encompass the well-known hyper-estimate of 30 million species of tropical arthropods. This supports the lower estimates made by several authors over the last two decades.

Original language | English (US) |
---|---|

Pages (from-to) | 357-365 |

Number of pages | 9 |

Journal | Oecologia |

Volume | 171 |

Issue number | 2 |

DOIs | |

State | Published - Jan 1 2013 |

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### Keywords

- Host specificity
- Model
- Monte Carlo
- Uncertainty

### Cite this

*Oecologia*,

*171*(2), 357-365. https://doi.org/10.1007/s00442-012-2434-5

**Estimating global arthropod species richness : Refining probabilistic models using probability bounds analysis.** / Hamilton, Andrew J.; Novotný, Vojtech; Waters, Edward K.; Basset, Yves; Benke, Kurt K.; Grimbacher, Peter S.; Miller, Scott E.; Samuelson, G. Allan; Weiblen, George D; Yen, Jian D.L.; Stork, Nigel E.

Research output: Contribution to journal › Article

*Oecologia*, vol. 171, no. 2, pp. 357-365. https://doi.org/10.1007/s00442-012-2434-5

}

TY - JOUR

T1 - Estimating global arthropod species richness

T2 - Refining probabilistic models using probability bounds analysis

AU - Hamilton, Andrew J.

AU - Novotný, Vojtech

AU - Waters, Edward K.

AU - Basset, Yves

AU - Benke, Kurt K.

AU - Grimbacher, Peter S.

AU - Miller, Scott E.

AU - Samuelson, G. Allan

AU - Weiblen, George D

AU - Yen, Jian D.L.

AU - Stork, Nigel E.

PY - 2013/1/1

Y1 - 2013/1/1

N2 - A key challenge in the estimation of tropical arthropod species richness is the appropriate management of the large uncertainties associated with any model. Such uncertainties had largely been ignored until recently, when we attempted to account for uncertainty associated with model variables, using Monte Carlo analysis. This model is restricted by various assumptions. Here, we use a technique known as probability bounds analysis to assess the influence of assumptions about (1) distributional form and (2) dependencies between variables, and to construct probability bounds around the original model prediction distribution. The original Monte Carlo model yielded a median estimate of 6. 1 million species, with a 90 % confidence interval of [3. 6, 11. 4]. Here we found that the probability bounds (p-bounds) surrounding this cumulative distribution were very broad, owing to uncertainties in distributional form and dependencies between variables. Replacing the implicit assumption of pure statistical independence between variables in the model with no dependency assumptions resulted in lower and upper p-bounds at 0. 5 cumulative probability (i. e., at the median estimate) of 2. 9-12. 7 million. From here, replacing probability distributions with probability boxes, which represent classes of distributions, led to even wider bounds (2. 4-20. 0 million at 0. 5 cumulative probability). Even the 100th percentile of the uppermost bound produced (i. e., the absolutely most conservative scenario) did not encompass the well-known hyper-estimate of 30 million species of tropical arthropods. This supports the lower estimates made by several authors over the last two decades.

AB - A key challenge in the estimation of tropical arthropod species richness is the appropriate management of the large uncertainties associated with any model. Such uncertainties had largely been ignored until recently, when we attempted to account for uncertainty associated with model variables, using Monte Carlo analysis. This model is restricted by various assumptions. Here, we use a technique known as probability bounds analysis to assess the influence of assumptions about (1) distributional form and (2) dependencies between variables, and to construct probability bounds around the original model prediction distribution. The original Monte Carlo model yielded a median estimate of 6. 1 million species, with a 90 % confidence interval of [3. 6, 11. 4]. Here we found that the probability bounds (p-bounds) surrounding this cumulative distribution were very broad, owing to uncertainties in distributional form and dependencies between variables. Replacing the implicit assumption of pure statistical independence between variables in the model with no dependency assumptions resulted in lower and upper p-bounds at 0. 5 cumulative probability (i. e., at the median estimate) of 2. 9-12. 7 million. From here, replacing probability distributions with probability boxes, which represent classes of distributions, led to even wider bounds (2. 4-20. 0 million at 0. 5 cumulative probability). Even the 100th percentile of the uppermost bound produced (i. e., the absolutely most conservative scenario) did not encompass the well-known hyper-estimate of 30 million species of tropical arthropods. This supports the lower estimates made by several authors over the last two decades.

KW - Host specificity

KW - Model

KW - Monte Carlo

KW - Uncertainty

UR - http://www.scopus.com/inward/record.url?scp=84872597729&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84872597729&partnerID=8YFLogxK

U2 - 10.1007/s00442-012-2434-5

DO - 10.1007/s00442-012-2434-5

M3 - Article

C2 - 22968292

AN - SCOPUS:84872597729

VL - 171

SP - 357

EP - 365

JO - Oecologia

JF - Oecologia

SN - 0029-8549

IS - 2

ER -