This is the most basic of information needed for any group of animals. That is, a list of the species present in an area. Usually that list is associated with some description (statistical and/or verbal) of completeness in relation to the potential number of species in the area. If done properly, species lists become the starting point for further investigations. They identify what is common, rich, or rare and help define what it is that is special or outstanding about the community being measured. When such lists are repeated, often after a wait of many years, these accumulated lists provide a coarse measure of changes in the status of species and a reference that current and future researchers, managers, and natural history students can refer to.

There are a number of ways to generate a species list and these often can be combined.

Recording the ad hoc observations of naturalists. The most basic of species lists is generated by compiling species presence from all available sources of information. Information can come from the logs and notes of staff and visitor’s or by recruiting and interviewing individuals who have spent time in the area. The completeness of the list will be very dependent upon the skills, notes, and coverage of the people available.

Hiring a specialist to find as many species as possible. This is often the best way to obtain a list that is as complete as possible that includes rare and specialized species and includes insights only available from someone who has spent their life studying the animals. All standardized counting and capturing techniques when applied in a random or systematic manner, will miss species. A specialist gets around that problem by using their intuition and knowledge about the life histories of species to find as many species as possible. For example, an expert on native bees would know that some bee species only come out at night, while other species are plant specialists, some specializing on willows and others on pickerelweed, hibiscus, or loosestrife. Some species are restricted in their nesting locations only occurring on exposed south-facing clay banks, others only in sand, etc. Standardized bee sampling techniques will get some of those species, but would miss many of the special cases that the bee specialist would readily identify. However, the completeness of the list is entirely dependent on the knowledge and skills of the specialist. The results are not repeatable, because specialists do not share the same knowledge base, which may be incomplete or wrong.

Standardized sampling. While the above approaches take advantage of the wisdom of the specialist, providing details about species that only a specialist can provide, they are limited by the fact that it would be impossible in the future to exactly duplicate the effort that went into the creation of that list. Thus it is difficult to compare lists made in this way between two separate time periods as differences could just have likely been due to differences in collectors as it could be differences in the species’ populations. While these lists will provide a great deal of insight into the presence and natural history of the species, they are usually inadequate as baselines for future comparisons. The way to rectify that problem is to approach the creation of a species list not as a one shot deal, but as a monitoring program, using a sound sampling frame, a strong sampling approach, and standardized techniques with long-time periods between surveys. The statistician and the natural history specialist can combine forces to increase the efficiency of probability surveys through stratification, including the best of both approaches.

Species list vs. Inventory. In the above discussion we might just have easily used the term “inventory” rather than “species list” in our descriptions. However, we have avoided using the term “inventory” as its meaning has been muddied by its use under many different contexts in the past, including quite a few circumstances that might better be classified as monitoring. The definition that we like is that an “inventory” is a one-shot deal, something meant not to be repeated, while “monitoring” is the situation where a piece of land is surveyed repeatedly over time for a group of animals. We feel that other than the simple circumstance of developing an annotated list of species (with or without the help of a paid expert) that all situations in which animals will be counted on piece of land should be so designed that they could be repeated in the future.

Some links for species lists:

Bioblitz. A Bioblitz is where you coerce a group of natural history experts to come to your patch of ground and find as many species as possible over a 24-hour period. Most will work for the fun of it if you provide plenty of food and drink. If you add the media and some educators your benefits will multiply.

National Park Service Inventory and Monitoring

British Columbia Species Inventory Fundamentals