Long-term effects of abandonment and restoration of Mediterranean meadows on butterfly-plant interactions

Abstract

Both the intensification and abandonment of traditional agricultural practices are known to be major threats to biodiversity worldwide, above all in industrialized countries. Although land abandonment in particular has a negative effect on the diversity of both plant and insect communities, few studies have ever analysed these two groups together and none has yet examined the effect on plant-insect interactions using a network approach. In view of the notable decline of pollinator insects reported in past decades, it is essential to understand how the structure of a plant-pollinator network changes during the ecological succession that occurs as traditionally managed habitats are abandoned, and to what extent this network is re-established when habitats are restored. We monitored a butterfly-plant network for 22 years in habitats where land abandonment and restoration have taken place and were able to compare restoration by grazing with restoration combining mowing and grazing. Abandonment leads to significant reductions in the cover of typical grasslands plants and, in turn, rapidly provokes changes in butterfly assemblages and plant interactions. Specifically, it caused a replacement of multivoltine by monovoltine species, increasing network specialization due to the great specificity in the interactions that monovoltine species established with plants. Changes in butterfly communities were also recorded in a nearby unaltered .

Estimating abundance and phenology from transect count data with GLMs

“…Studies have found warmer temperatures leading to higher population abundance in most butterfly species in the UK (Roy et al 2001) and a mixture of butterfly abundance responses to temperature in Spain (Stewart et al 2020). In contrast, Isaac et al (2011) found butterfly density in England was generally lower in regions with higher temperatures, and Colom et al (2021) found warmer summers were associated with smaller butterfly populations on the Spanish island of Menorca. In Massachusetts USA, butterfly populations near their species' northern range limits are generally increasing, and populations near their species southern range limits are generally decreasing (Breed et al 2012, Michielini et al 2021.…”

“…While it is becoming increasingly rare, objectively problematic metrics for phenological patterns such as first or last observations are still used by at least some ecologists (Colom et al 2022021, Fric et al 2020). For many types of data sets, observations of first and last events are known to be biased, as the day of first or last observation depends in part on population size and detectability (Miller‐Rushing et al 2008, Van Strien et al 2008, Inouye et al 2019).…”

Modern approaches for leveraging biodiversity collections to understand change in plant-insect interactions

“…Historically, these approaches include flower bagging experiments, observations of floral visitation, and pollen identification from insect specimens as described above. These approaches are rarely combined, and pollination studies are dominated by observational methods and quantitative literature reviews, typically with a focus on flower visitation observations for estimating network parameters (Yamaji and Ohsawa, 2016;Colom et al, 2021;Mendes et al, 2022). Visitation network studies typically consist of observation periods in which the researcher observes and records the visitors to a particular plant in an allotted time period.…”

Concurrent Butterfly, Bat and Small Mammal Monitoring Programmes Using Citizen Science in Catalonia (NE Spain): A Historical Review and Future Directions

“…Essential Biodiversity Variables (EBVs) covered by every monitoring programme as primary and secondary targets, defined as in [7]. The CBMS has made significant contributions to knowledge on the effect of global change on Mediterranean butterflies, including the effects of climate change on phenology and population dynamics [62][63][64][65], the significance of current landscape changes on butterfly communities [66][67][68] and, more generally, a robust assessment of butterfly trends at the regional scale [47,69,70]. From a practical perspective, data from the CBMs have been used to evaluate the effects of several managing practices [68,71,72].…”

“…The CBMS has made significant contributions to knowledge on the effect of global change on Mediterranean butterflies, including the effects of climate change on phenology and population dynamics [62][63][64][65], the significance of current landscape changes on butterfly communities [66][67][68] and, more generally, a robust assessment of butterfly trends at the regional scale [47,69,70]. From a practical perspective, data from the CBMs have been used to evaluate the effects of several managing practices [68,71,72]. Moreover, the assembled dataset has provided invaluable information in various autoecological studies [73][74][75][76] and has also been used in combination with data from other similar schemes to reveal ecological patterns and responses at the continental level [13,77,78].…”