1. Protected areas (PAs) are increasingly being used worldwide for the conservation and management of wildlife. Systematic conservation planning (SCP) aims at ensuring biodiversity persistence while minimizing the threats faced by the species and/or the economic costs related to protection. To account for spatio-temporal interactions between species and human threats, conservation planning for mobile wildlife requires time-series data derived from monitoring of species and human threats, a process that is costly and technically challenging. Therefore, assessments of the monitoring period needed to ensure sufficient data input in the design of efficient, adequate and representative networks of PAs are crucial.
2. We demonstrated the value of time-series data in conservation planning by implementing SCP and data from different monitoring periods to identify priority conservation areas for highly mobile marine megafauna accounting for their main threat: commercial fishing. Two analyses of ten reserve-design scenarios each, replicated as many times as the data composing each scenario permitted were run in Marxan. The best solutions of the planning scenarios were statistically compared using the Cohen`s Kappa test. We also assessed differences in spatial similarity among and within scenarios using the Wilcoxon non-parametric test and a non-metric multidimensional scaling analysis. Finally, we compared the necessary cost and the area selected for each scenario.
3. Our study highlights the importance of time-series ecological and socioeconomic data for the robust selection of priority conservation areas. The results revealed different thresholds of the minimum temporal data required to design efficient networks of PAs for highly mobile species, demonstrating that the incorporation of data covering longer periods to the scenarios produce a more robust selection of priority conservation areas. Conservation plans using data covering less than three years were missing important priority areas.
4. Synthesis and applications. We provide a method for estimating the minimum number of years of monitoring required to design efficient networks of protected areas that ensure the persistence of highly mobile species such as cetaceans and seabirds. This method can be used within an adaptive management framework to evaluate whether a network of PAs performs as planned, and to test whether management strategies should be altered or adjusted in response to local and global changes.

Species spatial distribution and abundance over a ten-year period (2007-2016) were obtained from (García-Barón et al., 2020). In this work, the yearly species spatial density was estimated based on sightings data collected during spring (March-April) within the PELACUS monitoring platform (Saavedra et al., 2018). Species data were analysed by means of Generalized Additive Models following the Information-Theoretic framework for the identification of the most important dynamic and static variables explaining the spatio-temporal patterns of the density of marine megafauna species.

García-Barón, I., Santos, M. B., Saavedra, C., Astarloa, A., Valeiras, J., García-Barcelona, S., & Louzao, M. (2020). Essential ocean variables and high value biodiversity areas: targets for the conservation of marine megafauna. Ecological Indicators, 117, 106504.

Saavedra, C., Gerrodette, T., Louzao, M., Valeiras, J., García, S., Cerviño, S., … Santos, M. B. (2018). Assessing the environmental status of the short-beaked common dolphin (Delphinus delphis) in North-western Spanish waters using abundance trends and safe removal limits. Progress in Oceanography, 166, 66-75. doi: 10.1016/j.pocean.2017.08.006