Insects are the most speciose animal group and perform diverse ecosystem functions. Yet, they are often neglected in large-scale conservation. As a consequence, many insect species are declining in different parts of the world [e.g., Chowdhury et al., In review].
Protected areas are the central part of a conservation plan and safeguard species from multifaceted natural and human-induced threats. However, when designing new protected areas, insects have rarely been considered focal species [Chowdhury et al., Trends in Ecology & Evolution], and 76% of insect species are inadequately covered by protected areas globally [Chowdhury et al., One Earth].
When species migrate, conserving them becomes more challenging, as any threat in any part of their migratory flyway can severely impact the entire population. For example, the iconic North American migratory monarch butterfly population has declined by > 80% over the last few decades.
Monarch butterfly (Danaus plexippus)
Using a list of 568 migratory butterfly species [Chowdhury et al., Biological Reviews] and seasonal classification [Chowdhury et al., Ecology Letters], we analysed how protected areas cover the geographic range of the annual cycle of butterfly migrants.
The protected area coverage was inadequate for 84% of migratory butterfly species in at least one season and 45% of species in all seasons. The proportion of species not meeting the representation target was highest in Hesperiidae (67%) and lowest in Pieridae (61%). Only 15% of species achieved target representation across all parts of the annual cycle.
Figure 1. Global protected area (PA) coverage for migratory butterflies relative to (a) climatically suitable area by season (colours defined in [b]), (b) frequency distribution of PA coverage across seasons (S1, S2, S3, S4), and (c) the extent of seasonal difference of PA coverage (maximum seasonal PA coverage − minimum seasonal PA coverage).
There was marked geographic variation in protected area coverage: 77% of species met representation targets in Sri Lanka, for example, but only 32% met targets in Italy. There were only 2 countries (Sri Lanka and Maldives) for which > 75% of migratory butterflies met their representation target. In contrast, there were 141 countries with < 50% species meeting their target and 59 countries (23%) with < 33% species meeting their representation target.
Figure 2. Percentages of migratory butterfly species meeting habitat representation targets for butterflies across species–season combinations (a–d) (white, no data from the country or territory).
The Kunming–Montreal Global Biodiversity Framework aims to increase the proportion of the world’s terrestrial, inland water, and marine and coastal areas in protected areas from the current 16% to 30% by 2030. This provides a unique opportunity for conservation planners to consider migratory species by ensuring that the expansion of PAs is coordinated across regions and international boundaries. This can be helpful in overcoming issues of poor resourcing and management in protected areas and may help focus attention on globally important as well as nationally important areas for migratory species conservation.
Our approach could be shaped to fit other migratory taxa (e.g., birds, mammals, fishes) because the dense occurrence data are collated temporally and spatially, which allows one to learn more about movements across the animal kingdom.
If you have any questions about this research, please email me at dr.shawanchowdhury@gmail.com.
Chowdhury, S., Cardillo, M., Chapman, J. W., Green, D., Norris, D. R., Riva, F., Zalucki, M. P., & Fuller, R. A. (2024). Protected area coverage of the full annual cycle of migratory butterflies. Conservation Biology, e14423. https://doi.org/10.1111/cobi.14423
