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iDNA from terrestrial haematophagous leeches as a wildlife surveying and monitoring tool - prospects, pitfalls and avenues to be developed.

Schnell IB, Sollmann R, Calvignac-Spencer S, Siddall ME, Yu DW, Wilting A, Gilbert MT - Front. Zool. (2015)

Bottom Line: Subsequently, we briefly address how the analytical challenges associated with leeches may apply to other sources of iDNA.Our review highlights that despite the considerable potential of leech (and indeed any) iDNA as a new survey tool, further pilot studies are needed to assess how analytical methods can overcome or not the potential biases and assumption violations of the new field of iDNA.Specifically we argue that studies to compare iDNA sampling with standard survey methods such as camera trapping, and those to improve our knowledge on leech (and other invertebrate parasite) physiology, taxonomy, and ecology will be of immense future value.

View Article: PubMed Central - PubMed

Affiliation: Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark ; Center for Zoo and Wild Animal Health, Copenhagen Zoo, Frederiksberg, Denmark.

ABSTRACT
Invertebrate-derived DNA (iDNA) from terrestrial haematophagous leeches has recently been proposed as a powerful non-invasive tool with which to detect vertebrate species and thus to survey their populations. However, to date little attention has been given to whether and how this, or indeed any other iDNA-derived data, can be combined with state-of-the-art analytical tools to estimate wildlife abundances, population dynamics and distributions. In this review, we discuss the challenges that face the application of existing analytical methods such as site-occupancy and spatial capture-recapture (SCR) models to terrestrial leech iDNA, in particular, possible violations of key assumptions arising from factors intrinsic to invertebrate parasite biology. Specifically, we review the advantages and disadvantages of terrestrial leeches as a source of iDNA and summarize the utility of leeches for presence, occupancy, and spatial capture-recapture models. The main source of uncertainty that attends species detections derived from leech gut contents is attributable to uncertainty about the spatio-temporal sampling frame, since leeches retain host-blood for months and can move after feeding. Subsequently, we briefly address how the analytical challenges associated with leeches may apply to other sources of iDNA. Our review highlights that despite the considerable potential of leech (and indeed any) iDNA as a new survey tool, further pilot studies are needed to assess how analytical methods can overcome or not the potential biases and assumption violations of the new field of iDNA. Specifically we argue that studies to compare iDNA sampling with standard survey methods such as camera trapping, and those to improve our knowledge on leech (and other invertebrate parasite) physiology, taxonomy, and ecology will be of immense future value.

No MeSH data available.


Related in: MedlinePlus

Components influencing detection probability. Panels represent three selected detection methods: a Vocal cues, b Camera traps and c Leech collection assuming presence of target species (and leech species). With vocal cues a, detection probability constitutes of p (Focal species sing), p (Observer hears song) and p (Correct identification of species by the observer). For camera traps (b) it is p (Focal species goes in front of camera trap), p (Camera is being triggered) and p (Correct identification of species by the observer). When using iDNA from leeches (and most other invertebrates) c, the detection probability constitutes of p (Leech feed on focal species), p (Fed leech collected), p (Target DNA extracted/amplified) and p (Correct identification based on the DNA)
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Fig3: Components influencing detection probability. Panels represent three selected detection methods: a Vocal cues, b Camera traps and c Leech collection assuming presence of target species (and leech species). With vocal cues a, detection probability constitutes of p (Focal species sing), p (Observer hears song) and p (Correct identification of species by the observer). For camera traps (b) it is p (Focal species goes in front of camera trap), p (Camera is being triggered) and p (Correct identification of species by the observer). When using iDNA from leeches (and most other invertebrates) c, the detection probability constitutes of p (Leech feed on focal species), p (Fed leech collected), p (Target DNA extracted/amplified) and p (Correct identification based on the DNA)

Mentions: Occupancy models [30, 52] treat species observations only as detections versus non-detections, rather than concluding presence versus absence. Over repeated visits to a collection of sampling sites, which are used to compensate for imperfect species detection, species detection/non-detection data can be used to estimate the probability of true species occurrence. Both occupancy and detection probability can furthermore be modelled as functions of environmental covariates (see TableĀ 3 and Fig. 3 for aspects that can influence target species detection probability in leech-based occupancy studies). Occupancy models provide estimates of the percentage of the total area occupied (PAO) and the probability of occupancy at any given site according to environmental covariates, which are parameters of great interest for many wildlife management programs.Table 3


iDNA from terrestrial haematophagous leeches as a wildlife surveying and monitoring tool - prospects, pitfalls and avenues to be developed.

Schnell IB, Sollmann R, Calvignac-Spencer S, Siddall ME, Yu DW, Wilting A, Gilbert MT - Front. Zool. (2015)

Components influencing detection probability. Panels represent three selected detection methods: a Vocal cues, b Camera traps and c Leech collection assuming presence of target species (and leech species). With vocal cues a, detection probability constitutes of p (Focal species sing), p (Observer hears song) and p (Correct identification of species by the observer). For camera traps (b) it is p (Focal species goes in front of camera trap), p (Camera is being triggered) and p (Correct identification of species by the observer). When using iDNA from leeches (and most other invertebrates) c, the detection probability constitutes of p (Leech feed on focal species), p (Fed leech collected), p (Target DNA extracted/amplified) and p (Correct identification based on the DNA)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4589908&req=5

Fig3: Components influencing detection probability. Panels represent three selected detection methods: a Vocal cues, b Camera traps and c Leech collection assuming presence of target species (and leech species). With vocal cues a, detection probability constitutes of p (Focal species sing), p (Observer hears song) and p (Correct identification of species by the observer). For camera traps (b) it is p (Focal species goes in front of camera trap), p (Camera is being triggered) and p (Correct identification of species by the observer). When using iDNA from leeches (and most other invertebrates) c, the detection probability constitutes of p (Leech feed on focal species), p (Fed leech collected), p (Target DNA extracted/amplified) and p (Correct identification based on the DNA)
Mentions: Occupancy models [30, 52] treat species observations only as detections versus non-detections, rather than concluding presence versus absence. Over repeated visits to a collection of sampling sites, which are used to compensate for imperfect species detection, species detection/non-detection data can be used to estimate the probability of true species occurrence. Both occupancy and detection probability can furthermore be modelled as functions of environmental covariates (see TableĀ 3 and Fig. 3 for aspects that can influence target species detection probability in leech-based occupancy studies). Occupancy models provide estimates of the percentage of the total area occupied (PAO) and the probability of occupancy at any given site according to environmental covariates, which are parameters of great interest for many wildlife management programs.Table 3

Bottom Line: Subsequently, we briefly address how the analytical challenges associated with leeches may apply to other sources of iDNA.Our review highlights that despite the considerable potential of leech (and indeed any) iDNA as a new survey tool, further pilot studies are needed to assess how analytical methods can overcome or not the potential biases and assumption violations of the new field of iDNA.Specifically we argue that studies to compare iDNA sampling with standard survey methods such as camera trapping, and those to improve our knowledge on leech (and other invertebrate parasite) physiology, taxonomy, and ecology will be of immense future value.

View Article: PubMed Central - PubMed

Affiliation: Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark ; Center for Zoo and Wild Animal Health, Copenhagen Zoo, Frederiksberg, Denmark.

ABSTRACT
Invertebrate-derived DNA (iDNA) from terrestrial haematophagous leeches has recently been proposed as a powerful non-invasive tool with which to detect vertebrate species and thus to survey their populations. However, to date little attention has been given to whether and how this, or indeed any other iDNA-derived data, can be combined with state-of-the-art analytical tools to estimate wildlife abundances, population dynamics and distributions. In this review, we discuss the challenges that face the application of existing analytical methods such as site-occupancy and spatial capture-recapture (SCR) models to terrestrial leech iDNA, in particular, possible violations of key assumptions arising from factors intrinsic to invertebrate parasite biology. Specifically, we review the advantages and disadvantages of terrestrial leeches as a source of iDNA and summarize the utility of leeches for presence, occupancy, and spatial capture-recapture models. The main source of uncertainty that attends species detections derived from leech gut contents is attributable to uncertainty about the spatio-temporal sampling frame, since leeches retain host-blood for months and can move after feeding. Subsequently, we briefly address how the analytical challenges associated with leeches may apply to other sources of iDNA. Our review highlights that despite the considerable potential of leech (and indeed any) iDNA as a new survey tool, further pilot studies are needed to assess how analytical methods can overcome or not the potential biases and assumption violations of the new field of iDNA. Specifically we argue that studies to compare iDNA sampling with standard survey methods such as camera trapping, and those to improve our knowledge on leech (and other invertebrate parasite) physiology, taxonomy, and ecology will be of immense future value.

No MeSH data available.


Related in: MedlinePlus