Using occurrence data to evaluate extinction reveals a strong resilience of butterflies in a National Park of Southern Europe (Alta Murgia National Park)

Butterflies from southernmost European regions encompass a large fraction of faunistic and genetic diversity but are also at the forefront of extinction risk for climate change. Nevertheless, monitoring schemes aimed at detecting their population trends were only recently established. In this study, we gathered all occurrence records of the 81 species of butterflies recorded for the Alta Murgia National Park (Italy, Apulia), a prime conservation area for butterflies. By using literature, citizen science, and unpublished sample data, we traced potential extinctions since 1966. We also provided a dedicated index to evaluate the potential extinction at the whole community level. We found that among the 29 species recorded before 2009, three were not recovered from 2009 to 2021. Another group of nine species was not recorded in the last five years. However, given the not standardized sampling methodology and the possibility that apparently disappeared species were due to inaccurate identification, we conclude that the butterfly community of the Park is showing a strong resilience. We hypothesize that such resilience may be attributed to the existence of the protected area and the presence of heterogeneous environments, which allow to buffer climatic changes and any other negative anthropic effects. The objective recognition of rare species in the surrounding region of 200 km ray also allowed identifying which species should be considered as prime targets for the conservation of local and regional diversity.

Local Habitat Characteristics Determine Butterfly Diversity and Community Structure in a Threatened Kihansi Gorge Forest, Southern Udzungwa Mountains, Tanzania

Background Many species inhabiting Kihansi gorge ecosystem in Southern Udzungwa mountains, Tanzania are threatened with extinction due to habitat loss caused by constructed hydropower plant that diverted over 90% of the water off the Kihansi River. Understanding ecological correlates and structure of an animal community in perturbed ecosystems is an important way to enhancing species conservation particularly in this system where several species are already threatened with extinction. This study assessed influences of local habitat characteristics on the butterfly abundance, species richness and diversity and examined how the butterfly community structures across three structurally heterogeneous habitats in the Kihansi gorge forest. Butterfly abundance data were collected using baited traps and measured environmental variables in the field where trapping occurred. To understand the diversity and butterfly richness, these parameters were computed under Primer software. Non-metric multidimensional scaling and analysis of community similarity were used to analyse the butterfly community structure. Further, the generalized linear models were used to assess how the measured variables explained observed species diversity, abundance, and richness. Results In total, 72 species of butterfly in five families were recorded. Butterfly, species diversity and richness did not vary across the habitat types or elevation gradient but showed strong correlation with some habitat characteristics. Also, there was evidence of butterfly communities structuring into distinct groups that showed greater separation associated with the habitat characteristics they utilise. Further, across the study area, butterfly species diversity was mostly likely to increase in high canopy and in trees with smaller diameter at breast height and at lower ground cover. Similarly, abundance significantly increased in the woodland and wooded grassland habitats, where there was high canopy and where tree density was high. Furthermore, butterfly species richness was strongly positively associated with high canopy cover and was mostly likely to increase in sites closer to water source. Conclusion Assessing habitat correlates of the butterfly communities provide important information on what components of the habitats are most useful to target when planning conservation especially in threatened ecosystems. This also helps to reveal existing gaps in important knowledge that would be useful to improving long-term monitoring of biodiversity in in fragile systems such as the Kihansi gorge forest.

Species traits affect phenological responses to climate change in a butterfly community

Diverse taxa have undergone phenological shifts in response to anthropogenic climate change. While such shifts generally follow predicted patterns, they are not uniform, and interspecific variation may have important ecological consequences. We evaluated relationships among species’ phenological shifts (mean flight date, duration of flight period), ecological traits (larval trophic specialization, larval diet composition, voltinism), and population trends in a butterfly community in Pennsylvania, USA, where the summer growing season has become warmer, wetter, and longer. Data were collected over 7–19 years from 18 species or species groups, including the extremely rare eastern regal fritillary Speyeria idalia idalia. Both the direction and magnitude of phenological change over time was linked to species traits. Polyphagous species advanced and prolonged the duration of their flight period while oligophagous species delayed and shortened theirs. Herb feeders advanced their flight periods while woody feeders delayed theirs. Multivoltine species consistently prolonged flight periods in response to warmer temperatures, while univoltine species were less consistent. Butterflies that shifted to longer flight durations, and those that had polyphagous diets and multivoltine reproductive strategies tended to decline in population. Our results suggest species’ traits shape butterfly phenological responses to climate change, and are linked to important community impacts.