Movements of a Specialist Butterfly in Relation to Mowing Management of Its Habitat Patches

It has been recognized that the timing of disturbance, in addition to its intensity and frequency, is important for the population dynamics of organisms because the impact of the disturbance depends on the life history stage at which it occurs (i.e., egg, larva, or adult). However, the effects of disturbance timing on consumer population dynamics have not been explored. This study simultaneously estimated the effects of mowing frequency and timing on the subpopulation dynamics of the endangered grassland butterfly, Plebejus argyrognomon. A two-year investigation of a metapopulation of P. argyrognomon consisting of approximately 150 habitat patches revealed that subpopulation size decreased with increasing mowing frequency, in addition to the positive effect of patch area and habitat connectivity. With the mowing frequency fixed at once per year, subpopulation size maximized when mowing occurred during the adult period in the previous generation, presumably due to reduced impact in the high-mobility adult stage. By mowing during this period, subpopulation size was maintained at several times higher than mowing during the larval period. It is suggested that disturbance timing should be incorporated into the conservation of metapopulations in human-managed landscapes. Implications for insect conservation Reducing mowing frequency is important for the conservation of P. argyrognomon. In addition, mowing during the adult stage is best suited for maintaining subpopulations.

Estimating appropriate mowing timing for the population of an endangered butterfly inhabiting grassland patches in an agricultural landscape

Deto,

Miyashita

2023

Conserving apollo butterflies: habitat characteristics and conservation implications in Southwest Finland

Kukkonen,

von Numers,

Brommer

2024

The conservation of insects, particularly endangered species such as the Apollo butterfly, is a pressing global concern. Understanding the habitat requirements and factors influencing species occupancy is crucial for designing effective conservation strategies. We focused on investigating the habitat characteristics expected to affect the occupancy of the nationally endangered Apollo butterfly in Southwest Finland. We conducted field surveys and GIS analysis to assess the impact of larval host plant and adult nectar resources, habitat encroachment, elevation, connectivity, and spatial variation on Apollo larval occupancy in rocky outcrop habitats. We found that rocky outcrops with abundant host plants and those less isolated from nectar patches play a significant role in supporting Apollo reproduction, whereas encroachment, specifically increased tree volume, negatively affected occupancy. We additionally observed spatial variation in occupancy across different blocks within the study area. Our findings emphasise the importance of resource availability for Apollo butterflies and highlight the dynamic nature of their habitat requirements. Maintaining a network of intact rocky outcrops with suitable resources is essential for the long-term persistence of the Apollo butterfly population in the region.Implications for insect conservation: Our research underscores the critical need to protect and restore habitats for the Apollo butterfly, particularly by addressing threats such as habitat encroachment and construction projects that pose risks to their breeding sites.

The higher abundance of host plant and suitable management recommended as the important elements in the conservation of Phengaris (Maculinea) teleius (Bergsträser, 1779) (Lepidoptera: Lycaenidae) in the Hradné lúky SAC meadows (Slovakia)

Masarovič,

Kršáková,

Lehotská

et al. 2024

This article presents a study of the isolated population of the scarce large blue butterfly, which is facing a significant threat in the meadows of the central part of Slovakia. The main objective of this study was to evaluate the effect of management, the presence of great burnet (Sanguisorba officinalis (L.)), and the host ants on the abundance of Phengaris teleius in the Hradné lúky Special Area of Conservation (SAC) in Slovakia. The study area was divided into six study plots. The abundance of S. officinalis host plant and ant communities, with emphasis on host ants (Myrmica scabrinodis (Nylander, 1846) and M. rubra (Linnaeus, 1758)), were analysed at each study plot. A generalized linear model (GLM) identified the significant relationships among three variables. Specifically, a relationship was confirmed between the number of P. teleius individuals and the abundance of the host plant S. officinalis, as well as between the number of P. teleius individuals and the current type of management at the specific biotope. The most important conservation recommendations regarding this study have been presented. Implications for insect conservation: Our results indicate that in the protection of P. teleius, it is important to support the abundance of S. officinalis as highly as possible. In addition, we confirm that targeted management with the absence of mowing in the critical phase of the year, especially in the Molinia meadows, is important for maintaining a healthy butterfly population.