Survey and Monitoring Data Quick-Start Guide A how-to for updating a Darwin Core dataset using the Humboldt Extension

Survey sampling design details the sampling strategy and how the survey event sites (e.g. stations, plots, transects) are laid out. The sampling event hierarchy is the translation of the survey sampling design into an event-based perspective using Darwin Core terms.

Historically, only two (2) terms were available to explicitly structure and relate different levels of sampling event hierarchy in a dataset: dwc:eventID and dwc:parentEventID. One additional Darwin Core event term, dwc:fieldNumber, provided a means by which to relate a sampling event with a dataset- or project-specific field number. The Humboldt extension provides an additional two (2) terms—eco:siteCount and eco:siteNestingDescription—to better support complex or nested datasets.

Review your DwC Event dataset to ensure that the survey design is accurately reflected in the use of the five (5) available sampling event hierarchy terms. Where additional events or event levels must be created, be sure to reference A Beginner’s Guide to Persistent Identifiers for guidance in creating new persistent identifiers.

Non-nested datasets may consist of a single sampling event with a single standardized sampling protocol that is not repeated (Figure 1a) or a series of single sampling events that are not joined by a larger parent event (Figure 1b).

Nested datasets (multiple nested event levels) are established by relating a child event to a parent event through the child Event’s dwc:parentEventID. The structure of these datasets can take various forms, but often center either first around the study site second and secondarily on protocol (Figure 2) or conversely, focusing on protocol at higher hierarchical levels and secondarily on locality (Figure 3). Alternatively, time-series dataset are temporally nested datasets (Figure 4).

The following information about a survey event site should be shared for every event level that the information is available:

The geographic location and extent of each survey event site should be shared. Historically, five (5) terms were strongly recommended for event datasets in GBIF:

These terms are still recommended. However, the Humboldt extension includes additional terms providing greater contextual information about the geospatial scope of a sampling event or series of events that should also be included if the information is available.

Vegetation cover at a survey event site can be reported in three ways:

If vegetation cover is reported using one or more of these methods, then eco:isVegetationCoverReported = TRUE; otherwise, eco:isVegetationCoverReported = FALSE.

Complete and accurate reporting of the temporal scope of a survey is crucial to asserting event structure and providing key contextual information about sampling conditions.

Refer to GBIF’s technical documentation on Date and time interpretation for more guidance on reporting event dates and times.

A sampling protocol provides the details of how the sampling was conducted. Clear communication of the sampling protocol implemented is essential to ensuring the reliability, reproducibility, and reusability of a dataset as detailed knowledge of survey methods facilitates data integration and subsequent analysis.

The nature of each sampling event (e.g., survey, inventory, bioblitz) should be reported using dwc:eventType. Event type should provide a high level overview of sampling effort type but should not be so specific as to overlap with sampling protocol. There is no single, standardized vocabulary for dwc:eventType. If your organization or community has a controlled vocabulary, it is recommended to use that vocabulary. Otherwise, you can refer to the box summarizing common event types below for guidance.

Inventory event types

samplingProtocol is required to publish an event dataset to GBIF, however the Humboldt extension includes three (3) terms to capture information about sampling protocol in a more structured manner:

The term eco:isLeastSpecificTargetCategoryQuantityInclusive provides a means by which to indicate to data users if an organismal occurrence record for a specific event reporting an explicit quantity of that organism via the paired terms dwc:organismQuantity and dwc:organismQuantityType represents the total number of that organism observed during the event. That is, it answers the question: is this the only record of that organism during the event?

Refer to Guidelines for eco:isLeastSpecificTargetCategoryQuantityInclusive for more information.

Two verbatim fields are available to provide additional information about an event.

Both fields can be applied to any event at any level.

The full verbatim scope explicitly identifying the full suite of stated parameters defining the breadth of a sampling event should be reported using eco:verbatimTargetScope. eco:verbatimTargetScope is particularly useful for capturing scope conditions not covered by existing taxonomic or organismal scope terms.

Sampling effort communicates sampling intensity during a sampling event. Clear reporting of sampling effort is necessary to interpret measures of completeness and calculate abundance (relative or absolute) or biomass and is critical in assessing the ability to compare information and aggregate data across studies.

dwc:samplingEffort is strongly recommended to publish dwc:Event datasets to GBIF, however, the Humboldt extension includes five (5) terms to more explicitly capture sampling effort information: