Glossary of Specialized Terms

The data underlying Surveyor is developed using the NatureServe network’s natural heritage methodology. This scientific methodology results from four decades of field work, analysis, collaboration, testing, and vetting. As such, some terminology is unique to the methodology or has evolved to have specific meaning in this context. Below are a few of these that you may encounter while using Surveyor. For a more in-depth understanding of NatureServe data, take our four-part Data Licensee Training and visit NatureServe Explorer.

Term Surveyor/Natural Heritage Definition

At-risk species

A species that has a conservation status rank of 1 (critically imperiled), 2 (imperiled), or 3 (vulnerable), as assessed by the NatureServe network, or that has legal status under the U.S. Endangered Species Act or the Canadian Species At Risk Act.

Common name

A colloquial or other informal name used for a species or taxon.

Conservation Status

An assessment of a species’ extinction risk, based on three factors: rarity, threats, and trends. Conservation status is ranked using a one-to-five scale, ranging from critically imperiled (1) to demonstrably secure (5); status is assessed and documented at distinct geographic scales: global (G) and subnational (S), such as a state or province.

Data steward

The NatureServe network member program that provided the data and that is the best source for more local information.

Detailed Report

A survey result that provides the highest level of detail: includes in-depth information about individual species and populations. For survey areas larger than 36 km2.

Element Occurrence

An area of land and/or water where a species is, or was, present, and which has practical conservation value. Element Occurrences, or “EOs,” for species commonly reflect populations or subpopulations that occur in appropriate habitat and at the appropriate time of year. When you survey an area of interest for the presence of at-risk species, NatureServe Surveyor determines if there is any spatial overlap between your area and an EO.

Fuzz (fuzzed, fuzzing)

Describes a record whose spatial footprint has intentionally been made less precise. Your survey may encounter this in cases where the exact locations are considered especially sensitive, such as where there are species that are subject to poaching.

In Detailed reports, the fuzzed flag is placed on individual element occurrences; in General reports, if *all* Element Occurrences for a given species have been fuzzed, Surveyor will flag that species record; in Known reports, if *all* the EO data in your output were fuzzed, Surveyor will flag the report.

General Report

A survey result that provides a medium level of detail: returns species by major taxonomic groups (e.g., 2 birds, 1 mammal). For survey areas between 10 km2 and 36 km2.

Known Report

A survey result that provides the lowest level of detail: returns simply a “Yes” or “No” as to whether species are known from the survey area. For survey areas less than 10km2. but greater than 2.6km2 (which is the minimum survey area).

Legal status

In the context of Surveyor reports, this refers to status under the U.S. Endangered Species Act or the Canadian Species at Risk Act.

Major taxonomic group

An informal grouping of plants and animals into taxonomic categories that we have found to be widely useful and understandable. Examples, used in the General Report, include:

  • Amphibians
  • Birds, Butterflies and Skippers
  • Conifers and relatives
  • Crayfishes
  • Dragonflies and Damselflies
  • Flowering Plants
  • Freshwater and Anadromous Fishes
  • Freshwater Mussels
  • Freshwater Snails
  • Lizards, Snakes, Turtles, and Crocodilians
  • Mammals

NatureServe rounded global status

A conservation status rank that reflects the rangewide (or “global”) condition of the species and that has been put through an algorithm to produce a value without qualifiers or ranges so that the final “rounded” rank is easier to interpret (e.g., a G2? would become G2; a G2G4 would become G3). Learn more at NatureServe Explorer.

NatureServe rounded subnational status

A conservation status rank that reflects the state or provincial condition of the species and that has been put through an algorithm to produce a value without qualifiers or ranges so that the final “rounded” rank is easier to interpret (e.g., an S2? would become S2; an S2S4 would become S3). Learn more at NatureServe Explorer.

Population viability

An assessment of the likelihood that a species population will persist at a location based on the size and condition of the Element Occurrence and its landscape context.

Rare species

A species that may be found in only one small area; is distributed widely but only in very specific habitats; AND/OR always exists in small numbers wherever it’s found. Some species may be rare in all three senses, such as a plant that only occurs as a small population on calcareous cliffs on one mountain. Rare species can be locally abundant and may or may not be at risk.

Scientific name

The formal scientific name for a species or taxon adopted for use by NatureServe based on standard botanical or zoological taxonomic references.


In the Surveyor context, species includes recognized subspecies and varieties as well as “full” species.