[en] 1. Regular monitoring of animal populations must be established to ensure wildlife
protection, especially when pressure on animals is high. The recent development
of drones or unmanned aircraft systems (UASs) opens new opportunities.
UASs have several advantages, including providing data at high spatial and temporal
resolution, providing systematic, permanent data, having low operational costs
and being low-risk for the operators. However, UASs have some constraints, such
as short flight endurance.
2. We reviewed studies in which wildlife populations were monitored by using
drones, described accomplishments to date and evaluated the range of possibilities
UASs offer to provide new perspectives in future research.
3. We focused on four main topics: 1) the available systems and sensors; 2) the
types of survey plan and detection possibilities; 3) contributions towards antipoaching
surveillance; and 4) legislation and ethics.
4. We found that small fixed-wing UASs are most commonly used because these
aircraft provide a viable compromise between price, logistics and flight endurance.
The sensors are typically electro-optic or infrared cameras, but there is the potential
to develop and test new sensors.
5. Despite various flight plan possibilities, mostly classical line transects have been
employed, and it would be of great interest to test new methods to adapt to the
limitations of UASs. Detection of many species is possible, but statistical
approaches are unavailable if valid inventories of large mammals are the purpose.
6. Contributions of UASs to anti-poaching surveillance are not yet well documented
in the scientific literature, but initial studies indicate that this approach
could make important contributions to conservation in the next few years.
7. Finally, we conclude that one of the main factors impeding the use of UASs is
legislation. Restrictions in the use of airspace prevent researchers from testing all
possibilities, and adaptations to the relevant legislation will be necessary in future.