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- Heterogeneity in habitat and microclimate delay butterfly community tracking of climate change over an elevation gradientPublication . Álvarez, Hugo Alejandro; Walker, Emma; M., Mingarro; Ursul, Guim; Cancela, JP; Bassett, Lee; Wilson, RobertGradients in community diversity and composition rarely track rates of warming, prompting efforts to understand the factors causing non-equilibrium responses to climatic change and their implications for conservation. Here, we test the roles of fine-resolution habitat heterogeneity and microclimate in delaying butterfly community responses to warming over a mountain elevation gradient. We assess species diversity and Community Temperature Index (CTI) in 2004–2005 and 2017 across 120 transect sites in the Sierra de Guadarrama (Spain), modelling temperatures based on topography, and vegetation structure based on LiDAR. A humped elevation gradient in species diversity was maintained over time. However, diversity in the later period was more positively related to vegetation heterogeneity, and sites with reduced rates of warming and greater forest cover maintained or increased their diversity. Site CTI declines with increasing elevation, showing little evidence of systematic change over the gradient between periods, although CTI increased most in locations with the greatest rates of spring microclimatic warming. Our results show that delays in community tracking of climatic conditions could result partly from positive effects of habitat and topographic heterogeneity providing microclimatic buffering against warming to existing communities; although barriers to colonization could also delay diversity increases and community thermophilization at high elevations. We suggest that protecting and managing complex habitats with high community diversity, and identifying localized microclimates that buffer populations against negative effects of warming, are more immediate conservation priorities over elevation gradients than efforts to ensure that communities track prevailing rates of warming.
- History of colonisation and updated distribution of the Monarch butterfly Danaus plexippus (Linnaeus, 1758) and its hostplants in mainland Portugal, Azores and MadeiraPublication . Palma, Luís; Vasconcelos, Sasha; Palmeirim, Ana Filipa; Cancela, JPABSTRACT: The first observations of the Monarch butterfly (Danaus plexippus) in Iberia date from 1886, although breeding records emerged almost a century later: 1960 in Spain, 1980s–1990s in Madeira and Azores, and 2003 in mainland Portugal. We reviewed the history of the colonisation of mainland and insular Portugal by the Monarch butterfly and its hostplants (Gomphocarpus fruticosus, G. physocarpus and Asclepias curassavica). We also compiled available historical and recent occurrence records as a basis for countrywide surveys of the butterfly and hostplants, to update their current distributions in Portugal. Locations for only a few of the older records represented newly rediscovered populations in the field, although recent occurrences were often confirmed. Hostplants were scarce and monarchs absent in northern and central mainland Portugal, but both were quite common in the southwest. In Madeira, hostplants were found in two locations, while monarchs were common and widespread. In the Azores, small hostplant patches were observed on four of seven surveyed islands, whereas monarchs were rare and restricted to two islands. Abandoned/semi-abandoned orange orchards represent the butterfly’s stronghold in Portugal, with the species being increasingly scarce along rivers and road verges where hostplants are declining. Hostplant persistence is unstable, with many patches removed, while others have expanded or colonised new areas. Overall, hostplants appear to be declining, with implications for the persistence of monarch butterflies in the country.
- Refugia from climate change, and their influence on the diversity and conservation of insectsPublication . Ursul, Guim; M., Mingarro; Cancela, JP; Helena, Romo; Wilson, RobertClimate change refugia are landscapes, topographic features or ecosystems that buffer organisms against exposure to climate change by providing conditions that are stable or spatially heterogeneous (macrorefugia) or distinct from their surroundings (microrefugia). Refugia allow taxa to persist through unfavorable climatic conditions and act as foci for subsequent recovery or range expansion, and could therefore underpin measures for adapting conservation to climate change. This chapter outlines physical and microclimatic features of refugia, and the evidence for their influence on insect responses to historical and recent climate change. It considers how vulnerability to climate change depends on how climate varies over space and time in refugia, but also on biotic traits (endemism, narrow climatic tolerance or habitat specialism) that may increase climate change sensitivity for species occupying these locations. The chapter concludes by reviewing proposals and remaining challenges for the practical application of climate change refugia to insect conservation.
- Forb diversity globally is harmed by nutrient enrichment but can be rescued by large mammalian herbivoryPublication . Nelson, Rebecca; Sullivan, Lauren; Hersch-Green, Erika; Seabloom, Eric; Borer, Elizabeth; Tognetti, Pedro; Adler, Peter; Biederman, Lori; Bugalho, Miguel; Caldeira, Maria; Cancela, Juan Pablo; Carvalheiro, Luísa; Catford, Jane; Dickman, Chris; Dolezal, Aleksandra; Donohue, Ian; Ebeling, Anne; Eisenhauer, Nico; Elgersma, Kenneth; Eskelinen, Anu; Estrada, Catalina; Garbowski, Magda; Graff, Pamela; Gruner, Daniel; Hagenah, Nicole; Haider, Sylvia; Harpole, W. Stanley; Hautier, Yann; Jentsch, Anke; Johanson, Nicolina; Koerner, Sally; Lannes, Lucíola; MacDougall, Andrew; Martinson, Holly; Morgan, John; Venterink, Harry; Orr, Devyn; Osborne, Brooke; Peri, Pablo; Power, Sally; Raynaud, Xavier; Risch, Anita; Shrestha, Mani; Smith, Nicholas; Stevens, Carly; Veen, G. F. Ciska; Virtanen, Risto; Wardle, Glenda; Wolf, Amelia; Young, Alyssa; Harrison, SusanABSTRACT: Forbs (“wildflowers”) are important contributors to grassland biodiversity but are vulnerable to environmental changes. In a factorial experiment at 94 sites on 6 continents, we test the global generality of several broad predictions: (1) Forb cover and richness decline under nutrient enrichment, particularly nitrogen enrichment. (2) Forb cover and richness increase under herbivory by large mammals. (3) Forb richness and cover are less affected by nutrient enrichment and herbivory in more arid climates, because water limitation reduces the impacts of competition with grasses. (4) Forb families will respond differently to nutrient enrichment and mammalian herbivory due to differences in nutrient requirements. We find strong evidence for the first, partial support for the second, no support for the third, and support for the fourth prediction. Our results underscore that anthropogenic nitrogen addition is a major threat to grassland forbs, but grazing under high herbivore intensity can offset these nutrient effects.
- Local Climatic Effects on Colonisation and Extinction Drive Changes in Mountain Butterfly CommunitiesPublication . Ursul, Guim; Mingarro López, Mario; Castro-Cobo, Sara; Cancela, Juan Pablo; Romo, Helena; Wilson, Robert; Wilson, Robert; Cooke, RobABSTRACT: Aim - The capacity of cool refugia to protect cold-adapted species against climate change may depend on both their initial climatic conditions and how quickly these change. We test how local climatic conditions influence mountain butterfly communities via their effects on colonisation and local extinction. Location - Four mountain ranges in Central Spain. Methods - We used community temperature index (CTI), based on the climatic niches of constituent species (species temperature index, STI), to estimate thermal affinities for butterfly communities sampled in 1984–2005 to 2017–2022. We related CTI to local temperature, estimated using the model Microclima, and tested for changes to local temperature and CTI over time. We used standard deviation in CTI (CTISD) and species richness to detect effects of colonisation and local extinction on community change. Finally, we tested for differences in thermal affinity and thermal niche breadth (STISD) between species undergoing local extinction or colonisation at each site. Results - CTI was positively related to local temperature in both periods. However, there were regional differences in rates of change in CTI and local temperature. CTI increased overall, even though temperatures decreased at many sites; and CTI increases were greatest in historically cool sites. Neither CTISD nor species richness changed overall, suggesting that communities experienced equivalent numbers of colonisations and extinctions. Colonising species had warmer thermal affinities than those undergoing local extinction, and species with broader thermal niches increased their occupancy most over time. Main Conclusions - Local climatic conditions influenced changes to community composition based on species thermal tolerances, resulting in the loss of communities where cool-affinity species predominated, and a narrower range of community thermal affinities overall. Our results suggest that a regional perspective to identifying climate change refugia is needed to provide a wide range of local climate conditions and rates of change to help adapt conservation to climate change.