Imperfect detection and its consequences for monitoring for conservation

Biodiversity monitoring is important to identify conservation needs and test the efficacy of management actions. Variants of “abundance” ( N ) are among the most widely monitored quantities, e.g., (true) abundance, number of occupied sites (distribution, occupancy) or species richness. We propose a sampling-based view of monitoring that clearly acknowledges two sampling processes involved when monitoring N . First, measurements from the surveyed sample area are generalized to a larger area, hence the importance of a probability sample. Second, even within sampled areas only a sample of units (individuals, occupied sites, species) is counted owing to imperfect detectability p . If p < 1, counts are random variables and their expectation E ( n ) is related to N via the relationship E ( n ) = N*p . Whenever p < 1, counts vary even under identical conditions and underestimate N , and patterns in counts confound patterns in N with those in p . In addition, part of the population N may be unavailable for detect...

[1]  J. Andrew Royle,et al.  Estimating species richness and accumulation by modeling species occurrence and detectability. , 2006, Ecology.

[2]  K. Pollock,et al.  Estimation of Detection Probability in Manatee Aerial Surveys at a Winter Aggregation Site , 2007 .

[3]  J. Andrew Royle,et al.  Hierarchical models of animal abundance and occurrence , 2006 .

[4]  C. Reading.  A proposed standard method for surveying reptiles on dry lowland heath , 1997 .

[5]  D. MacKenzie.  Occupancy Estimation and Modeling: Inferring Patterns and Dynamics of Species Occurrence , 2005 .

[6]  P. Geissler,et al.  Density estimation in wildlife surveys , 2004 .

[7]  Darryl I MacKenzie,et al.  Sampling design trade-offs in occupancy studies with imperfect detection: examples and software. , 2007, Ecological applications : a publication of the Ecological Society of America.

[8]  J. Andrew Royle,et al.  Hierarchical Modeling and Inference in Ecology: The Analysis of Data from Populations, Metapopulations and Communities , 2008 .

[9]  Andrew Gelman,et al.  Data Analysis Using Regression and Multilevel/Hierarchical Models , 2006 .

[10]  B. Sandercock.  Estimation of Demographic Parameters from Live-Encounter Data: a Summary Review , 2006 .

[11]  S. Buckland.  Introduction to distance sampling : estimating abundance of biological populations , 2001 .

[12]  Duane R. Diefenbach,et al.  INCORPORATING AVAILABILITY FOR DETECTION IN ESTIMATES OF BIRD ABUNDANCE , 2007 .

[13]  K. Pollock,et al.  Comparing Population Size Estimators for Plethodontid Salamanders , 2004 .

[14]  J. Nichols,et al.  ESTIMATING SITE OCCUPANCY, COLONIZATION, AND LOCAL EXTINCTION WHEN A SPECIES IS DETECTED IMPERFECTLY , 2003 .

[15]  William A. Link,et al.  Controlling for varying effort in Count surveys : An analysis of Christmas Bird Count data , 1999 .

[16]  J Andrew Royle,et al.  Site Occupancy Models with Heterogeneous Detection Probabilities , 2006, Biometrics.

[17]  F. W. Preston.  The Invisible Birds , 1979 .

[18]  Theodore R. Simons,et al.  Sampling plethodontid salamanders : Sources of variability , 2001 .

[19]  Kenneth H. Pollock,et al.  Large scale wildlife monitoring studies: statistical methods for design and analysis , 2002 .

[20]  J. Andrew Royle,et al.  ESTIMATING SITE OCCUPANCY RATES WHEN DETECTION PROBABILITIES ARE LESS THAN ONE , 2002, Ecology.

[21]  Douglas H. Johnson.  In Defense of Indices: The Case of Bird Surveys , 2008 .

[22]  B. L. Boeuf,et al.  ESTIMATING POPULATION SIZE IN ASYNCHRONOUS AGGREGATIONS: A BAYESIAN APPROACH AND TEST WITH ELEPHANT SEAL CENSUSES , 2007 .

[23]  David R. Anderson,et al.  Model selection and multimodel inference : a practical information-theoretic approach , 2003 .

[24]  J. Nichols,et al.  IMPROVING INFERENCES IN POPULATION STUDIES OF RARE SPECIES THAT ARE DETECTED IMPERFECTLY , 2005 .

[25]  Brendan A. Wintle,et al.  PRECISION AND BIAS OF METHODS FOR ESTIMATING POINT SURVEY DETECTION PROBABILITIES , 2004 .

[26]  K. Pollock,et al.  SPATIAL AND TEMPORAL VARIATION IN DETECTION PROBABILITY OF PLETHODON SALAMANDERS USING THE ROBUST CAPTURE–RECAPTURE DESIGN , 2004 .

[27]  R. Little.  To Model or Not To Model? Competing Modes of Inference for Finite Population Sampling , 2004 .

[28]  J Andrew Royle,et al.  Generalized site occupancy models allowing for false positive and false negative errors. , 2006, Ecology.

[29]  Urs Hintermann,et al.  Scale and trends in species richness: considerations for monitoring biological diversity for political purposes , 2004 .

[30]  T. M. F. Smith,et al.  The Foundations of Survey Sampling: A Review , 1976 .

[31]  M. Kéry,et al.  Estimating species richness: calibrating a large avian monitoring programme , 2005 .

[32]  J. Andrew Royle,et al.  ESTIMATING ABUNDANCE FROM REPEATED PRESENCE–ABSENCE DATA OR POINT COUNTS , 2003 .

[33]  J. Nichols,et al.  Occupancy estimation and modeling with multiple states and state uncertainty. , 2007, Ecology.

[34]  B. Schmidt,et al.  Monitoring the distribution of pond‐breeding amphibians when species are detected imperfectly , 2005 .

[35]  H. Marsh,et al.  Correcting for visibility bias in strip transect aerial surveys of aquatic fauna , 1989 .

[36]  Marc Kery,et al.  Inferring the absence of a species -- a case study of snakes , 2002 .

[37]  J. Andrew Royle,et al.  HIERARCHICAL SPATIAL MODELS OF ABUNDANCE AND OCCURRENCE FROM IMPERFECT SURVEY DATA , 2007 .

[38]  N. Yoccoz.  Occupancy Estimation and Modeling. Inferring patterns and dynamics of species occurrence , 2006 .

[39]  W. Kendall,et al.  HOW SHOULD DETECTION PROBABILITY BE INCORPORATED INTO ESTIMATES OF RELATIVE ABUNDANCE , 2002 .

[40]  Kenneth H. Pollock,et al.  Separating components of detection probability in abundance estimation: an overview with diverse examples , 2004 .

[41]  J. Andrew Royle,et al.  Species richness and occupancy estimation in communities subject to temporary emigration. , 2009, Ecology.

[42]  M. Conroy,et al.  Analysis and Management of Animal Populations , 2002 .

[43]  William L. Kendall,et al.  ROBUSTNESS OF CLOSED CAPTURE-RECAPTURE METHODS TO VIOLATIONS OF THE CLOSURE ASSUMPTION , 1999 .

[44]  M. Kéry,et al.  How biased are estimates of extinction probability in revisitation studies? , 2006 .

[45]  W. Hochachka,et al.  Trends in trappability and stop-over duration can confound interpretations of population trajectories from long-term migration ringing studies , 2008, Journal of Ornithology.

[46]  J. Andrew Royle,et al.  A Bayesian state-space formulation of dynamic occupancy models. , 2007, Ecology.

[47]  R. Dorazio.  On the choice of statistical models for estimating occurrence and extinction from animal surveys. , 2007, Ecology.

[48]  Darryl I. MacKenzie,et al.  Designing occupancy studies: general advice and allocating survey effort , 2005 .

[49]  W. Link,et al.  Seasonal components of avian population change: joint analysis of two large-scale monitoring programs. , 2007, Ecology.

[50]  Anthony Arak,et al.  Callers and satellites in the natterjack toad: evolutionarily stable decision rules , 1988, Animal Behaviour.

[51]  J. Nichols,et al.  Inferences About Landbird Abundance from Count Data: Recent Advances and Future Directions , 2009 .

[52]  W. Kendall,et al.  Making Great Leaps Forward: Accounting for Detectability in Herpetological Field Studies , 2007 .

[53]  M. Kéry,et al.  Species richness estimation and determinants of species detectability in butterfly monitoring programmes , 2007 .

[54]  D. MacKenzie.  WHAT ARE THE ISSUES WITH PRESENCE–ABSENCE DATA FOR WILDLIFE MANAGERS? , 2005 .

[55]  B. Schmidt,et al.  Declining amphibian populations: The pitfalls of count data in the study of diversity, distributions, dynamics, and demography , 2004 .

[56]  David J. Spiegelhalter,et al.  WinBUGS user manual version 1.4 , 2003 .

[57]  B. Schmidt,et al.  Monitoring distributions using call surveys: estimating site occupancy, detection probabilities and inferring absence. , 2005 .

[58]  Hugh P Possingham,et al.  Presence–Absence versus Abundance Data for Monitoring Threatened Species , 2006, Conservation biology : the journal of the Society for Conservation Biology.