Appendix N: How to calculate home ranges

Step-by-step instructions for generating accurate home ranges from public data.

Home ranges need to be validated from public data. Accepted sources in order of preference are peer-reviewed research papers, academic theses, public datasets, expert opinion, and NGO/policy reports.

Many rare animals have poor documentation on their characteristics. Most projects will need to satisfy independent expert reviewers for the home ranges they have decided to use. We have strong hopes that this science will become more standardized and open-source in the future. For now, we've established a database that experts are welcome to contribute to to make the science and calculations on home ranges more transparent and robust.

Basic protocols for home range research:

• Home range estimates are reported in sq km.

• Use primary references only.

• If there is no published information on the home range for a species, use information from the closest relative possible.

• Exclude simulation studies and estimates of exclusive (non-overlapping) areas.

• For migratory bird species, report the breeding home range.

• If possible, report the annual home range (except for breeding home range of migratory birds). If only seasonal home range estimates are reported, calculate and report the average.

• If multiple home range estimates are reported based on different methods, calculate and report the average.

• If a list or table of individual home ranges is provided instead of a reported average, first calculate the mean home range for females and the mean home range for males. Then, calculate and report the overall average of these two means.

• If the list or table of individual home ranges contains fewer than 10 female/male individuals, calculate and report the average. If the list contains 10 or more individuals, calculate and report the median.

• If only minimum and maximum values are reported, calculate and report their average.

• If the provided average home ranges do not align with our protocol (e.g., lacking gender-weighted averages), still use the averages as provided in the article; only calculate averages if the authors do not provide any.

• We will use the average of reported home range estimates from primary sources for our ISBM, except when there are more than 10 references for a given species, in which case we will use the median.

• For indicator plants or trees, use mean seed dispersal distance. (Tip, Tamme et al. 2014 provide an extensive database to look up species in Supplement 1!) If primary data is not available, estimate from genus or family data, or use Lososova et al. 2023 or Appendix 3 in Thomson et al. 2011 to extrapolate.

Example database

An example, open-science public database of home ranges for Savimbo projects is reported below.