No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Poleward shifts in the geographical ranges of butterfly species associated with global warming
... Concernant la remontée vers le nord, des chercheurs ont mis en évidence une avancée de la distribution d'oiseaux britanniques tel que Cettia cetti, de 18,9 km en 20 ans (0.945 km/an) (Thomas & Lennon, 1999). En Europe, sur 52 espèces de papillons non migrateurs, une étendue de leur distribution vers le nord de 35 à 240 km a été observée chez 65% d'entre eux, pas de changement chez 34% et une rétraction au sud chez 2% (Parmesan et al., 1999). Concernant la marge sud de distribution, sur 40 espèces, 22% ont présenté une rétraction au nord, 72% ont eu une distribution stable et 5% ont vu leur distribution s'étendre vers le nord depuis 30 à 100 ans (Parmesan et al., 1999). ...
... En Europe, sur 52 espèces de papillons non migrateurs, une étendue de leur distribution vers le nord de 35 à 240 km a été observée chez 65% d'entre eux, pas de changement chez 34% et une rétraction au sud chez 2% (Parmesan et al., 1999). Concernant la marge sud de distribution, sur 40 espèces, 22% ont présenté une rétraction au nord, 72% ont eu une distribution stable et 5% ont vu leur distribution s'étendre vers le nord depuis 30 à 100 ans (Parmesan et al., 1999). Dans l'ouest de l'Amérique du nord, l'aire de répartition du papillon Euphydryas editha s'est étendue 28 de 92 km vers le nord et 124 m vers les hautes altitudes. ...
... Dans la littérature, il y a peu d'études qui concernent la contraction de l'aire de distribution en basse latitude et altitude (Parmesan et al., 1999;Franco et al., 2006;Bourougaaoui et al., 2021a). Ceci peut s'expliquer par la difficulté de déterminer les extinctions à large échelle (contrairement aux colonisations) ainsi que les absences. ...
Face au changement climatique, des modifications de la distribution et de la phénologie des espèces ont été observées. La processionnaire du pin (PP) (Thaumetopoea pityocampa) est considérée comme un modèle d’étude pour comprendre l’effet du réchauffement climatique sur la distribution des espèces car sa distribution s’étend en réponse à l’augmentation des températures hivernales. La PP est un ravageur forestier à impact économique et sanitaire. L’apparition de processions précoces atypiques dans certaines régions a été observée ces dernières années. Cependant, les conséquences du changement climatique sur sa phénologie restent encore peu connues. Une meilleure compréhension des variations spatiales et temporelles de la phénologie est cruciale, non seulement pour mieux comprendre l’effet du changement climatique sur la PP, mais aussi pour optimiser les méthodes de lutte et prévenir des risques d’urtication étant donné qu’il est nécessaire pour cela de savoir quand les différents stades larvaires sont présents. Afin de tester l’hypothèse d’une variation de la phénologie dans le temps (du fait du changement climatique) et dans l’espace (du fait des différents types de climats rencontrés en France), des suivis de la période de vol, du développement larvaire et de la période de procession ont été réalisés de 2018 à 2021 dans plusieurs régions biogéographiques en France. Ces données ont été comparées aux données historiques datant des années 1970-1980. Un potentiel étalement du vol et peu de variation dans la période de procession ont été mis en évidence. La phénologie de l’espèce varie dans l’espace en fonction des températures de l’été, de la date des premiers gels et de la rigueur de l’hiver. Afin d’identifier les mécanismes responsables de ces variabilités phénologiques, un modèle mathématique a été développé pour prédire les stades phénologiques de l’œuf jusqu’au dernier stade larvaire. Celui-ci a été calibré sur les courbes de performances thermiques des différents stades de la PP, obtenues en conditions contrôlées, à partir de la population d’Orléans. Les valeurs des paramètres de ces courbes étaient effectivement différentes selon les stades. Le modèle a ensuite été validé de manière indépendante grâce aux données de suivis réalisés à Orléans durant l’étude. L’augmentation de la température globale et/ou des vagues de chaleur en automne expliqueraient l’occurrence de processions précoces. Face au changement climatique, ces processions devraient donc être plus fréquentes. Le modèle a ensuite été testé sur cinq autres populations suivies durant cette étude, situées dans des régions climatiques différentes. Celui-ci rend bien compte de la variabilité spatiale de la phénologie observée. Le modèle phénologique prend comme variable la température de l’air. Or, les larves se trouvent dans un nid de soie. Dans le but de déterminer et simuler le microclimat associé au nid, un modèle biophysique a été développé. Le nid confère un microclimat chaud pouvant impacter le développement et potentiellement la survie des larves. En mesurant la tolérance thermique des différents stades larvaires,différents seuils thermiques ont été identifiés. Les résultats obtenus dans cette thèse montrent qu’il est important de considérer les contraintes de développement et de survie de chaque stade afin de prédire correctement l’effet des conditions climatiques sur la phénologie et la survie de la PP. Ils montrent aussi clairement que les changements de phénologie de la PP sont en lien avec le changement climatique. Ainsi la PP pourrait être un modèle d’étude pour comprendre l’effet du changement climatique sur la distribution et la phénologie des espèces, deux composantes étroitement liées.
... The growing season of trees in Europe has extended by 11 days on average since the early 1960s (Menzel and Fabian, 1999). There have been poleward shifts in the ranges of butterflies (Parmesan, 1996(Parmesan, , 1999, birds (Thomas and Lennon, 1999), and mammals (Hersteinsson and MacDonald, 1992). There have also been upward shifts in the altitudinal ranges of plants (Wardle and Coleman, 1992;Grabherr et al., 1994;Meshinev and Apostolova, 2000;Kullman, 2001), butterflies (Parmesan, 1996) and birds (Pounds et al., 1999). ...
... Of course, the desire to cover a broad area has to be balanced by the need to collect data in sufficient detail so as to observe changes with confidence, as was discussed in Chapter 3. Furthermore, in order to reliably detect shifts in species range in response to climate change, it may not be sufficient to look at abundance at a particular location, even at range edges. Studies throughout the range of a species may be needed to distinguish range shifts from local changes in abundance, range expansions or contractions (Parmesan, 1996(Parmesan, , 1999. ...
... Even with the best-designed studies, it will rarely be possible to draw firm conclusions about the effects of climate change on ecosystems. Therefore, in order to build a strong case that climate change is having detectable impacts on natural systems, comparisons have been made (Walther et al, 2002;Parmesan and Yohe, 2003) across studies of large numbers (circa 1700) of species, including rocky shore invertebrates Sagarin et al., 1999), butterflies (Parmesan, 1999), birds (Thomas and Lennon, 1999) and plants (Grabherr et al., 1994;Fitter and Fitter, 2002), in many different ecosystems. ...
p>During the 20<sup>th</sup> century, anthropogenic emissions of greenhouse gases have caused global mean temperatures to rise by 0.4-0.8<sup>o</sup>C. Further warming of 0.4-1.1<sup>o</sup>C is projected by 2050. Climate change during the 20<sup>th</sup> century has had effects on many terrestrial and marine ecosystems. This thesis investigates the effects of changes in climate on rocky shore communities in the Bay of Biscay, northeast Atlantic. This is a zone of biogeographical transition with sharp temperature gradients resulting in unusual spatial patterns of cold- and warm-temperate species, likely to be particularly sensitive to climate change.
Chapters 2 and 3 collect existing data on climate and species distributions in the region and analyse the data in novel ways. Chapters 3, 4 and 5 present and analyse new data on the distribution of rocky shore species in the region, and on the mechanisms of their responses to environmental gradients in temperature and other physical factors. Chapter 6 develops an original model based on existing and new data on the distribution and responses to climate of key rocky shore species.
In Chapter 2 analysis of several data sets showed that both summer and winter, sea and air temperatures in the Bay of Biscay region have on the whole risen since 1950, at a rate consistent with the global average rate of warming. There have, however, been warmer and colder periods, and local variations. Indices of upwelling calculated from alongshore wind stress show increasing trends throughout the 20<sup>th</sup> century in northwest Spain and northern Portugal; no clear trends were found along the north central coast of Spain.
In Chapter 3, analyses of past studies and my surveys during 2000-01 show that the distribution of rocky shore species in the Bay of Biscay has varied considerably since 1895. The abundance and distribution of several common cold-temperate species of brown algae on the north coast of Spain show significant negative correlations with variation in temperature during the 20<sup>th</sup> century, suggesting that climate change has indeed affected these species. The species studied are ecologically important canopy-forming algae: the changes in distribution observed are thus likely to have had important consequences for rocky shore communities in the region as a whole.
In Chapter 4, the responses of two common and ecologically important species of limpet, Patella vulgata L. (cold-temperate) and P. depressa Pennant (warm-temperate), to the gradient in sea temperature along the coast of northern Spain, and the mechanisms governing these responses, were investigated. The abundance of the two species and (especially) two indices of their relative abundance, log<sub>10</sub> (Pv/Pd) and Pv(Pv+Pd), were strongly correlated with summer temperature. A similar relationship of relative abundance of the same two species with spatial variations in summer sea temperature was found in data collected in the 1950s in the English Channel.</p
... These mismatches should in turn result in range-wide asymmetries in population growth rates with positive rates at the upper latitudinal or altitudinal range edges, and negative ones at low-latitude or altitude edges. Such asymmetries in population growth rates could presage large-scale geographical range shifts (Lenoir & Svenning, 2015;Parmesan et al., 1999;Sexton et al., 2009). Yet, we know little about how widespread asymmetries in marginal population growth rates are. ...
... Overall, our results support the notion that the performance of marginal populations -animal or plant, terrestrial or marine -is sensitive to a changing climate, with performance at LLMs being especially negatively affected by warming. Given that differences in marginal population performance can represent an early indicator of impending range shifts (Lenoir & Svenning, 2015;Parmesan et al., 1999), our results indicate that many extant species ranges are not in equilibrium with current climates, but poised to decline at LLMs and increase at HLMs even though they have to date not experienced perceivable shifts. Our results also represent further evidence that an enhanced representation of demographic and dispersal dynamics could increase the realism of population-based approaches to species distribution modelling (Shipley et al., 2022). ...
Aim: Range shifts are expected to occur when populations at one range margin perform better than those at the other margin, yet no global trend in population performances at range margins has been demonstrated empirically across a wide range of taxa and biomes. Here we test the prediction that, if impacts of ongoing climate change on performance in marginal populations are widespread, then populations from the high-latitude margin (HLM) should perform as well as or better than central populations, whereas low-latitude margin (LLM) populations should perform worse.
Location: Global.
Time period: 1995-2019.
Major taxa studied: Plants and animals.
Methods: To test our prediction, we used a meta-analysis to quantify empirical support for asymmetry in the performance of high-and low-latitude margin populations compared to central populations. Performance estimates (survival, reproduction, or lifetime fitness) for populations occurring in their natural environment were derived from 51 papers involving 113 margin-centre comparisons from 54 species and 705 populations from the Americas, Europe, Africa and Australia. We then related these performance differences to climatic differences among populations. We also tested whether patterns are consistent across taxonomic kingdoms (plants vs animals) and across realms (marine vs terrestrial).
Results: Populations at margins performed significantly worse than central popula-tions, and this trend was primarily driven by the low- latitude margin. Although the dif-ference was of small magnitude, it was largely consistent across biological kingdoms and realms. Differences in performance were weakly (p= .08) related to the differ-ence in average temperatures between central and marginal populations.
Main conclusions: The observed asymmetry in performance in marginal populations is consistent with predictions about the effects of global climate change, though fur-ther research is needed to confirm the effect of climate. It indicates that changes in demographic rates in marginal populations can serve as early-warning signals of impending range shifts.
... For example, many species of birds and mammals are shifting their ranges in response to climate change, with some species moving towards the poles or to higher elevations in order to find cooler temperatures (Parmesan et al., 1999). Similarly, many species of plants are colonizing new areas as they become more suitable due to changing temperatures and other environmental factors (Ackermann et al., 2011). ...
... In addition to genetic changes, living beings are also adapting to temperature increase through behavioral changes. For example, a study of marine invertebrates (such as crabs and lobsters) found that many species are shifting their distribution towards cooler waters in response to warming temperatures (Parmesan et al., 1999). Similarly, a study of birds in the United Kingdom found that many species are shifting their breeding times to earlier in the year in response to warming temperatures, with some species showing a higher capacity for behavioral adaptation than others (Both et al., 2006). ...
Climate change is a major global challenge, with increasing mean annual temperatures driven by human activities having significant impacts on the Earth's ecosystems and the species that depend on them. As temperatures continue to rise, many species will be faced with the challenge of adapting to changing conditions in order to survive. In this text, we will explore how living beings are adapting to temperature increase due to climate change, with a focus on two fundamental mechanisms: (i) dispersal abilities and (ii) adaptive capacity. We will also examine some specific examples of how these mechanisms are helping species to adapt to the changing climate.
Moreover, we will try to figure out how three key factors, notably: the abrupt or shuttle behavioral changes, tactical range shifts, and many other physiological adaptations, get modified strategically through evolution that gives the species a buffer and a chance to thrive in the changing natural conditions like temperature or traits related to it like rainfall or other precipitations.
... Sustained climate change has profound implications for multiple aspects of species biology, including impacts on distribution, habitat associations and phenology (Parmesan et al., 1999;Davies et al., 2006;Jamieson et al., 2012;Halsch et al., 2021). At broader temporal and spatial scales, these species-specific biological changes can translate into large shifts in both ecological interactions within communities *Corresponding author. ...
... More commonly, however, latitudinal and elevational shifts are observed. Latitudinal shifts involve more coldadapted species expanding their northern boundary and/or contracting their southern boundary (Parmesan et al., 1999;Hickling et al., 2006), and elevational shifts involve similar movement relative to elevational gradients (Buse et al., 2001;Birkett et al., 2018). Taken together, these changes in behaviour, habitat selection and phenology, along with the prevalence and importance of insects for ecosystem structure and function, can create substantial downstream ecological and evolutionary effects. ...
As dominant features of most ecosystems, insects are responsive to changes in climate, both over short temporal scales (e.g. seasonal fluctuations in abundance) and over longer evolutionary scales (e.g. decade-scale changes in patterns of biodiversity). One such taxonomic group that is sensitive to changing climate are the craneflies (Diptera: Tipulidae). Here, we used aggregated biodiversity data to examine elevational and latitudinal distributions of adult Tipulidae between 1976 and 2019 in Wales, UK, and we related these distributions to climatic patterns. Our analyses showed that species with earlier-emerging adults were most affected by weather conditions in the year before observation. Specifically, as temperature increased, observed elevation increased in high-precipitation conditions, remained stable in average-precipitation conditions and decreased in low-precipitation conditions. For species with later-emerging adults, associations were seen between elevation and weather conditions in the year of observation. Observed latitude generally exhibited a negative association with maximum temperature in the year before observation, with observations of Tipulidae trending southwards during the 43-year study period. Our results support consideration of emergence phenology, weather and habitat data when predicting species distributional changes attributable to climate change, which is vital in understanding the selection pressures that species face in a changing environment.
... As bioindicators they have certain advantages because of being ubiquitous in a wide range of environments, and moderate in growth rate and population turnover (Hodkinson and Jackson 2005). As one of the more better known insect groups taxonomically, butterflies have been used as indicator taxa for biodiversity assessment studies (Stork et al 2003) as well as towards monitoring ecosystem responses to environmental perturbations (Howard et al 1998, Parmesan et al 1999 all over the world. ...
... Butterflies have thus occupied a prominent place in assessing conservation progress and biodiversity assessments (Ulrich andBuszko 2003, Stork et al 2003). Butterflies have also been identified as an important indicator taxa towards monitoring ecosystem responses to environmental perturbations (Howard et al 1998, Parmesan et al 1999, Cleary 2004, including climate change Sparks 2000, Stefanescu et al 2003), as well as serving as a barometer of the overall community complexity in an ecosystem (Hutzinger 2003). They are also extremely sensitive to changes in certain microclimatic conditions usually affected by habitat degradation such as humidity, temperature and light-levels (Murphy et al. 1990). ...
One of the fundamental goals in ecology is to explain the spatial and temporal patterns of biological diversity. This is important as it helps in determining associations of environmental variables with observed patterns of community similarity in order to understand mechanisms that may influence beta diversity. Moreover, it is also crucial in determining appropriate locations for nature reserves as well as in assessment of management strategies with respect to exploitation of forest resources. Butterflies are one of the better known invertebrate taxon in the world. With an estimated 20,000 species in the world, they occupy a prominent place in conservation efforts and biodiversity assessments as they can serve as a valuable barometer of overall community complexity, especially in tropical forests.
The Garo hills in Meghalaya, north-eastern India, is part of the Indo-Burma biodiversity hotspot region. Vast swathes of this autonomous region are occupied by tropical forests, the majority of which are community-managed. Covering a spatial extent of approximately 605 sq.km., the Balpakram-Baghmara (BBL) landscape in the South Garo hills district of the region encompasses the largest protected area in the state - Balpakram National Park (BNP) - as well as smaller state-managed reserved forests. In such a landscape where protected areas, community-managed forests, monoculture plantations and shifting cultivation (locally called jhum) co-exist, the main aim of this study was to assess and compare the butterfly assemblages in each of these land-management categories in order to determine the effect of rapid land-use change on butterfly communities.
I enumerated butterflies during time-constrained 30-minute counts in all four treatment areas between March and May 2014. I surveyed different sites only once during this period, but took a total of 298 counts covering varied vegetation types and land-management systems. During these counts I captured individual butterflies for identification purposes if needed, and released them on the spot. I also recorded environmental variables such as light, relative humidity and temperature during all counts.
Comparison of diversity indices and extrapolated species richness for each treatment revealed that the community-owned and managed forests were not significantly different from the state-owned forested tracts. Both harboured a similar composition of habitat-specialist species as well. Butterfly communities in monoculture plantations and jhum landscape differed significantly from those found in forests (state- or community-managed) and were highly depauperate in terms of habitat specialist species. Climatic variables of light, temperature and relative humidity did not seem to affect butterfly communities in a significant manner across treatments, although they did exert an overall effect on butterfly species richness and abundances.
The study highlights the importance of community forests in butterfly conservation, and perhaps to biodiversity conservation in general, in the Garo Hills. It also suggests that the rapidly changing land-use pattern being witnessed in these areas, with forests making way for monoculture plantations, might pose a threat to such diverse ecological assemblages. It might be worth considering innovative ways of involving people with forest conservation activities in order to preserve the unique and varied biota of the region.
... Among the most well-documented groups include birds (Thomas and Lennon 1999;Probst et al. 2003;Root et al. 2003), butterflies and other insects (Thomas et al. 2001;Chen et al. 2011), marine fishes (Last et al. 2011), marine invertebrates (Southward et al. 1995;Sagarin et al. 1999;Zacherl et al. 2003;Rivadeneira and Fernández 2005), and mammals (see below). Factors driving these expansions appear to be recent changes in climate (Parmesan et al. 1999;Thomas 2010) and/or human alterations to landscapes (Gilchrist et al. 2015;Walsh and Tucker 2018). Monitoring changes in species distributions is important because as species disperse into new areas, novel ecological interactions are inevitable (Alexander et al. 2015). ...
Extralimital records have been noted for several mammals in North America at local scales, but it is yet to be determined how the entire geographic distribution has changed for many of
these species. Updated distributions are provided for eight species of mammals that are broadly expanding their ranges in North America. Distributional data was collected from museum records and published literature for an initial group of mammals that showed evidence of range expansions. This list was reduced to species that were expanding in three or more states/provinces
and where an updated distribution had not been published in the past 20 years. Eight species of mammals were identified using these criteria. Three species show movement in an overall
westward direction, two are moving north, one is moving west and north, and one each is moving east and south. Monitoring changes in species distributions is important for identifying novel
ecological interactions and predicting potential routes of disease spread
... There is widespread evidence of biological responses to climate change by insects (Bartomeus et al., 2011;Wilson & Fox, 2021), including mismatches in phenology (Roy & Sparks, 2000) and changes R. G. Mateo and M. L. Munguira contributed equally to this study. in abundance (Lister & Garcia, 2018) or geographic ranges (Parmesan et al., 1999). Recent declines in insect diversity and abundance (Forister et al., 2019;Hallmann et al., 2017) are driven at least in part by climate change (Conrad et al., 2006;Halsch et al., 2021;Raven & Wagner, 2021;Wagner, 2020;Wagner et al., 2021). ...
1. Taxa restricted to mountains may be vulnerable to global warming, unless local-scale topographic variation and conservation actions can protect them against expected changes to the climate. 2. We tested how climate change will affect the 19 mountain-restricted Erebia species of the Iberian Peninsula, of which 7 are endemic. 3. To examine the scope for local topographic variation to protect against warming, we applied species distribution models (HadGEM2 and MPI) at two spatial scales (10 Â 10 and 1 Â 1 km) for two representative concentration pathways (RCP4.5 and RCP8.5) in 2050 and 2070. We also superimposed current and future ranges on the protected area (PA) network to identify priority areas for adapting Erebia conservation to climate change. 4. In 10 Â 10 km HadGEM2 models, climatically suitable areas for all species decreased in 2050 and 2070 (average À95.7%). Modelled decreases at 1 Â 1 km were marginally less drastic (À95.3%), and 14 out of 19 species were still expected to lose their entire climatically favourable range by 2070. 5. The PA network is well located to conserve the species that are expected to retain some climatically suitable areas in 2070. However, we identify 25 separate 10 Â 10 km squares where new PAs would help to adapt the network to expected range shifts or contractions by Erebia. 6. Based on our results, adapting the conservation of range-restricted mountain taxa to projected climate change will require the implementation of complementary in situ and ex situ measures alongside urgent climate change mitigation.
... In response to changing climate, species could alter their physiological tolerance via evolutionary processes, but given the rapid pace of climate change and mobility of raptors, range shifts that track their thermal niches are likely to predominate . Range shifts are well documented in a variety of taxa (e.g., Parmesan et al. 1999, Vors and Boyce 2009, Zuckerberg et al. 2009, Huang et al. 2017, including raptors (Paprocki et al. 2014, McCaslin andHeath 2020), and at different time frames (Parmesan 2006, Tingley et al. 2009, Saupe et al. 2019. The predominant trend for range shift is poleward and increased elevation, but the direction and magnitude of range shifts can vary by species, life history, dietary habits, and habitat, with notable differences between wintering and breeding ranges (see Migration section below; Reside et al. 2010, Hovick et al. 2016, Curley et al. 2020, although many raptors display a propensity for northward shifts (Paprocki et al. 2014, McCaslin andHeath 2020). ...
... "globálního oteplování" či "globální změny klimatu" na motýly jsou studovány velmi intenzívně. Právě na motýlech byly vůbec poprvé přesvědčivě ukázány vlivy oteplujícího se klimatu na biotu, konkrétně severojižní posuny výskytu (Parmesan et al. 1999, Parmesan 2006, výškové posuny výskytu (Konvička et al. 2003, Wilson et al. 2005) a proměna struktury celých společenstev (Gonzalez-Megias et al. 2008), a to zejména v horských oblastech . Intenzívně též byly a jsou studovány fenologické změny, jako časování doby letu či změny v počtu generací (Roy & Sparks 2000, Crespo & Gutierrez 2011, Diamond et al. 2011. ...
Metodika zahrnuje všechny přírodní biotopy v České republice a věnuje se péči o ohrožené zástupce jak nočních, tak denních motýlů. Naopak všechny předchozí studie se omezovaly jen na stanoviště lesní nebo nelesní, případně motýly denní nebo noční.
Vedle důkladné znalosti relevantní literatury používá Metodika údaje o početnosti, stanovištní vazbě a nárocích na péči jednotlivých druhů získané z obrovských objemů dat, shromážděných pro denní motýly, a pro tzv. „malé čeledi“ motýlů nočních, v databázi „Mapování motýlů České republiky“. Na sběru dat se podílejí ročně stovky amatérů i profesionálů. S nejaktivnějšími z nich autoři konzultovali stanovištní nároky druhů, navíc lokality prakticky všech ohrožených druhů byly navštíveny v roce zpracování Metodiky a nároky ohrožených druhů upřesněny. Novátorská je analýza příčin ohrožení, konfrontující moderní poznatky o ohrožení denních a nočních motýlů, stejně jako přístup k jednotlivým typům stanovišť, které jsou pojímány spíš podle celkové fysiognomie vegetačního krytu než podle druhového složení. Vedle standardních zemědělských (seč, pastva) a lesnických (prosvětlování korunového patra, pěstování nízkých a středních lesů) doporučení obsahuje metodika i diskusi k perspektivním přístupům – radikálnějšímu mechanickému managementu a volné pastvě velkých herbivorů, která je slibnou alternativou pro velká a různorodá území.
... Populations of a given species that occupy lower latitudes and low elevations have to transverse the greatest distance to reestablish their bioclimatic associations, and they probably need to migrate through land use types that are unfavorable for them (Dale et al., 2001). Among European and North American butterflies, subpopulations that resided lowlands and southernmost habitats have undergone local extinction with climate change (Parmesan et al., 1999). Local extinctions yield adverse impacts on metapopulation dynamics and genetic heterozygosity of a species. ...
... When conditions for sustaining a population in the long-term are no longer viable, it would be ideal for a species to be able to move and expand into available habitats that are within the bounds of their ecological limitations. Although populations located at the edge of distributions are usually marginal or constrained due to a variety of reasons such as climate, predation, and geographic barriers, the very same peripheral populations can be sources for future range expansions with their leading "head start" and adaptive genetics (Durka, 1999;Gibson et al., 2009;Hampe & Petit, 2005;Parmesan et al., 1999;Parmesan & Yohe, 2003). Studying the nature of biotic and abiotic factors that drive a population's dynamics throughout a species' distribution is valuable to improve the success of conservation and management of the species (Light & MacConaill, 2011;Römer et al., 2021;Seddon et al., 2013). ...
In a time of global change, having an understanding of the nature of biotic and abiotic factors that drive a species' range may be the sharpest tool in the toolbox of conservation and management of threatened species. However, such information are lacking for most tropical and epiphytic species due to the complexity of life history, the roles of stochastic events, and the diversity of habitat across the span of a distribution. In this study, we conducted repeated census across the core and peripheral range of Trichocentrum undulatum, a threatened orchid that is found throughout the island of Cuba (species core range) and southern Florida (the northern peripheral range). We used demographic matrix modeling and stochastic simulations to investigate the impacts of herbivory, hurricanes, and logging (in Cuba) on projected population growth rates (λ and λs) among sites. Our study indicates that the Florida population is under high extinction risk and most populations in the core range show less interannual variability, but, with the exception of one population, are also in decline. The peripheral population experienced higher herbivory damage than did the core populations, by a native inflorescence‐crippling fly, Melanagromyza miamensis, and an invasive, mortality‐triggered scale, Diaspis boisduvalii. The latter was found in the Florida population only. Hurricanes increased levels of mortality and had a negative effect on λ. However, λ increased following hurricane events due to increased recruitment and decreased herbivory. Life table response experiments suggest that higher adult survival was the largest contributor to the higher λ observed in the growing Cuba populations, as compared with the population in Florida. Logging simulations in Cuba indicate that populations can maintain stability only if selective logging of host trees occurs at low frequency. Reintroduction of the species in its northern peripheral habitat is needed to ameliorate the threats from sea‐level rise and invasive herbivorous insects to secure the current species' northern, continental range margin. Our study exhibits how vital rates and ecological interactions vary across a species distribution and respond under differing stochastic events.
... In other respects, our results showed an altitudinal shift among CG of A. c. costata, which agrees with the results found in species of insects (Parmesan et al., 1999;Deutsch et al., 2008), birds (Thomas and Lennon, 1999), mammals (Hersteinsson and MacDonald, 1992) and plants (Hansen et al., 2001). These modifications can induce alterations in community structure and in the relative abundance of species, as well as increases in habitat fragmentation and population extinction (Davis et al., 1998;Peterson et al., 2002). ...
... Both marine and terrestrial species that cannot adapt fast enough due to the rate of warming, have been shifting their ranges towards higher elevations or latitudes (Parmesan and Yohe 2003, Chen et al. 2011, Pecl et al. 2017; though certain species may be able to both adapt and move simultaneously (Socolar et al. 2017, Román-Palacios andWiens 2020). If species cannot physically move at a rate which tracks the climatic shifts, they face a high risk of extinction (Parmesan et al. 1999, Devictor et al. 2008, Feeley et al. 2011, Fadrique et al. 2018. ...
Global change has been predominantly studied from the prism of ‘how much' rather than ‘how fast' change occurs. Associated to this, there has been a focus on environmental drivers crossing a critical value and causing so‐called regime shifts. This presupposes that the rate at which environmental conditions change is slow enough to allow the ecological entity to remain close to a stable attractor (e.g. an equilibrium). However, environmental change is occurring at unprecedented rates. Equivalently to the classical regime shifts, theory shows that a critical threshold in rates of change can exist, which can cause rate‐induced tipping (R‐tipping). However, the potential implications of R‐tipping in ecology remain understudied. We aim to facilitate the application of R‐tipping theory in ecology with the objective of identifying which properties (e.g. level of organisation) increase susceptibility to rates of change. First, we clarify the fundamental difference between tipping caused by the magnitude as opposed to the rate of change crossing a threshold. Then we present examples of R‐tipping from the ecological literature and seek the ecological properties related to higher sensitivity to rates of change. Specifically, we consider the role of the level of ecological organisation, spatial processes, eco‐evolutionary dynamics and pair–wise interactions in mediating or buffering rate‐induced transitions. Finally, we discuss how targeted experiments can investigate the mechanisms associated to increasing rates of change. Ultimately, we seek to highlight the need to better understand how rates of environmental change may induce ecological responses and to facilitate the systematic study of rates of environmental change in the context of current global change.
... Butterflies are useful indicators of ecological condition as they respond quickly to environmental changes (Warren et al., 2001), including changes in distribution due to climate (Devictor et al., 2012;Parmesan et al., 1999). This is ...
Biodiversity accounting is promoted as a way of improving the conservation of species and ecosystems. Advancing the theory and practice of biodiversity accounting is driven by the United Nation's standardization of ecosystem accounting in 2021 and a desire to make production of ecosystem accounts commonplace and useful. While the theory of biodiversity accounting has advanced, in practice few accounts have been produced and all have focused on iconic or threatened species. We present a set of novel biodiversity accounts for the 92 butterfly species of the Australian Capital Territory (ACT), spanning 1978–2021, using historical records and systematic surveys of 224 sites between 2014–15 and 2020–21 in the Southern Hemisphere survey season (Spring‐Autum). We conclude that species level biodiversity accounting is useful for biodiversity conservation and that species accounting must go beyond accounting for iconic and threatened species and reflect other characteristics, such as the distribution, abundance, residential status, breeding status, endemism, and ecological status of all species. Habitat specialization provides a link to ecosystem condition accounting, with changes in the distribution and abundance of habitat specialists a likely indicator of ecosystem condition. With such information, species accounts can be used to assess and target conservation activity and examples for ACT butterflies are provided. Biodiversity accounting is a way of organizing information to improve the conservation of species and ecosystems. We present butterfly accounts for the Australian Capital Territory, Australia, covering 92 species and spanning the years 1978–2021. We conclude that to be useful for biodiversity conservation, biodiversity accounting must the reflect the distribution, abundance, residence, breeding status, endemism, and habitat specialization of all species, and not just iconic or endangered species.
... Butterflies are sensitive and react rapidly to climate and habitat changes (Kunte 1997;Warren et al. 2001;Padhye et al. 2006;Molina-Martínez et al. 2016;Schmitt et al. 2021). For example, global warming and anthropogenic land use have been shown to affect butterfly species range shifts -uphill or pole-ward (Parmesan et al. 1999;Konvicka et al. 2003;Pateman et al. 2012;Molina-Martínez et al. 2016). Thus, understanding the seasonal dynamics of butterflies as a community has great relevance. ...
Long-term socioeconomic progress requires a healthy environment/ecosystem, but anthropogenic activities cause environmental degradation and biodiversity loss. Constant ecological monitoring is, therefore, necessary to assess the state of biodiversity and ecological health. However, baseline data are lacking even for ecologically sensitive regions such as the Western Ghats. We looked at the seasonality and polyphenism of butterflies of the central Western Ghats to obtain baseline population patterns on these charismatic taxa. We recorded 43118 individuals (175 species) using fortnightly time-constrained counts for two consecutive years and found the peak abundance (49% of the total individuals) in the post-monsoon period (October to January). Seasonal abundance was correlated with the overall increase in species richness. Habitat differences were stronger than seasonality as samples clustered based on sites. Several species also displayed polyphenism with distinct distributions of wet and dry season forms. Seasonal equitability and indicator species analysis showed distinct inter-species differences in seasonality patterns. This work provides key baseline data on the seasonal dynamics of butterflies of the Western Ghats in the context of climate change and conservation. It will help monitor this ecologically sensitive region using butterflies.
... Among the 25% of native species that demonstrated phenological advances, the transition is ten times as stark-an average of 1 day earlier each year. The phenological changes observed here appeared less common than geographic range shifts in arthropods (only 25% of ant species showing earlier mating seasons versus 2/3 to 3/4 of arthropod taxa demonstrating poleward or upward shifts in range, Parmesan et al. 1999;Hickling et al. 2006;Chen et al. 2011) but more drastic in impact. The 1-day advance in mating phenology per decade among all ants-equivalent to adopting the mating season of a population 100 m lower in elevation-is an order of magnitude larger than typical elevational range shifts of only ~ 10 m per decade (Hickling et al. 2006;Chen et al. 2011), highlighting the role of phenological shifts in allowing organisms to rapidly respond to climate change. ...
Understanding an organism’s phenology is crucial for predicting the effects of anthropogenic impacts like climate change. Yet we lack a basic understanding of reproductive timing in one of Earth’s most prominent animal groups—the ants. I perform the first large-scale study of the geography of ant mating phenology by synthesizing collection data from museum databases. By compiling museum records of specimens in reproductive condition from across the contiguous U.S. and dating back over a century, I explore how ant mating seasons vary with latitude and elevation and test whether they have shifted in response to climate change. Ant mating seasons occurred about 1 day later in the year for each 100-m gain in elevation or degree increase in latitude and were also shorter and less variable at higher latitudes. Consistent with predicted impacts of climate change, 25% of native species have shifted their mating seasons earlier by an average of 0.9 days per year. Across all ants, mating dates have been advancing about 1 day earlier per decade. The results represent the first attempt at a regional geography of ant mating phenology and highlight shifts in mating season as a mechanism mediating the responses of ants to climate change.
... In fact, climate change is predicted to become the dominant driver of global species decline in the coming future (Di Marco et al., 2019). With the increasing temperature, species need to move polewards to track suitable environmental conditions and prevent widespread extinction (Thomas et al., 2004), which has been documented in many taxa (Hickling et al., 2006;Hill et al., 1999;Parmesan, 1996;Parmesan and Yohe, 2003;Parmesan et al., 1999;Wilson et al., 2005;Pöyry et al., 2009;Amano et al., 2014;Garcia et al., 2014;Warren et al., 2018). Climate-induced shifts in a species distribution commonly involve movement towards higher latitude (with a median rate of 1.69 km/year) and higher elevation (with a median rate of 1.1 m/year; Chen et al., 2011). ...
Climate change is a major threat impacting insects globally, yet the impact on tropical insects is largely unknown. Here, I assessed the climatic vulnerability of Bangladeshi butterflies (242 species). About 42 % of species could experience range contraction, and the impact could be significantly more severe among threatened species. Depending on Socio-Economic Pathways (ssps), the future climatic condition could be unsuitable for 2 (ssp126) – 34 % (ssp585) species. The mean elevation of the suitable habitat could increase by 238 %, and the situation could be more severe for the threatened butterflies. Further, 54 % of the realised niche of butterflies could be altered. Although there might be no significant association between the shift in habitat suitability along the elevational gradient, migratory species could experience a more significant shift than non-migrants. Overall, climate change could have a severe impact on Bangladeshi butterflies. To mitigate insect decline globally and meet the Post 2020 Biodiversity Framework targets, immediate detection of climate change impact on tropical insects and developing effective conservation strategies is essential.
... Naturally, the thermal environment is not the only factor that can preclude the northward spread. Nevertheless, systematic shifts in distribution limits of many species toward higher latitudes with the ongoing climate warming (Parmesan et al. 1999;Parmesan 2006;Breed et al. 2013;Tiitsaar et al. 2019) provide evidence of a major role of temperature in determining distribution ranges. The evolution of thermal tolerance in insects must be slow as it has not facilitated comparable shifts over thousands of years passed since the end of the ice age. ...
Temperature has a profound effect on the growth and development of ectothermic animals. However, the extent to which ecologically driven selection pressures can adjust thermal plastic responses in growth schedules is not well understood. Comparing temperature‐induced plastic responses between sexes provides a promising but underexploited approach to evaluating the evolvability of thermal reaction norms: males and females share largely the same genes and immature environments but typically experience different ecological selection pressures. We proceed from the idea that substantial sex differences in plastic responses could be interpreted as resulting from sex‐specific life‐history optimization, whereas similarity among the sexes should rather be seen as evidence of an essential role of physiological constraints. In this study, we performed a meta‐analysis of sex‐specific thermal responses in insect development times, using data on 161 species with comprehensive phylogenetic and ecological coverage. As a reference for judging the magnitude of sex specificity in thermal plasticity, we compared the magnitude of sex differences in plastic responses to temperature with those in response to diet. We show that sex‐specific responses of development times to temperature variation are broadly similar. We also found no strong evidence for sex specificity in thermal responses to depend on the magnitude or direction of sex differences in development time. Sex differences in temperature‐induced plastic responses were systematically less pronounced than sex differences in responses induced by variations in larval diet. Our results point to the existence of substantial constraints on the evolvability of thermal reaction norms in insects as the most likely explanation. If confirmed, the low evolvability of thermal response is an essential aspect to consider in predicting evolutionary responses to climate warming.
... Among insect bioindicators, butterflies stand out as the best known and most studied group (McGeoch, 1998;Thomas, 2005;Hill et al., 2021), monitored in many places around the world following the BMS framework (Butterfly Monitoring System; Pollard & Yates, 1994), with multiple studies reporting insect responses to the effects of climate change (Hill et al., 2021;Parmesan et al., 1999;Rödder et al., 2021). The genus Coenonympha Hubner, 1819 (Nymphalidae, Satyrinae) constitutes a relatively diverse Holarctic group, with around 30 species in the Palearctic and 2 in the Nearctic (Bozano, 2002;García-Barros et al., 2013; but also see Wiemers et al., 2018Wiemers et al., , 2020 propose a total of 20 Palearctic species with 18 in Europe). ...
1. Identifying which species are being negatively impacted by climate change and the mechanisms driving their decline is essential to effectively protect biodiversity. 2. Coenonympha pamphilus is a common and generalist butterfly, widely distributed throughout the Western Palearctic, being multivoltine in southern Europe. Previous studies indicate that it will not be substantially affected by climate change; however , it has seemingly disappeared from the southeast of the Iberian Peninsula in the last decades. 3. Here, we aim to determine if it has effectively disappeared from this area, as well as identify the environmental conditions limiting its distribution and the potential causes behind this a priori local extinction. 4. We downloaded all the occurrence records of C. pamphilus and analysed their spatial and temporal trends. To identify the climatic variables driving the distribution of this butterfly in the Iberian Peninsula, we performed an ensemble species distribution model (SDM), combining 600 individual models produced with 6 algorithms. 5. We confirmed that C. pamphilus has not been observed in the southeast of the Iberian Peninsula since 2008. Aridity was the main factor limiting the distribution of C. pamphilus in our ensemble SDM, with areas with high aridity being unsuitable for this species. 6. We hypothesise that multivoltinism is the mechanism driving this local extirpation, as high aridity is causing host plants (Poaceae) to wither prematurely, precluding the development of the second and/or third generations of the butterfly. Even though generalist species are theoretically more resilient to climate change, other traits such as multivoltinism may increase their vulnerability and need to be further investigated. Abstract 1. Para proteger eficazmente la biodiversidad es esencial identificar qué especies están siendo afectadas negativamente por el cambio climático y los mecanismos que impulsan su declive. Ecological Entomology. 2022;1-15. wileyonlinelibrary.com/journal/een 1 2. Coenonympha pamphilus, es una mariposa diurna común y generalista, ampliamente distribuida por el Paleártico occidental, siendo polivoltina en el sur de Europa. Estu-dios previos indican que no se verá sustancialmente afectada por el cambio climá-tico. Sin embargo, parece haber desaparecido del sureste de la Península Ibérica. 3. Aquí, pretendemos determinar si efectivamente ha desaparecido de esta zona, así como identificar las condiciones ambientales que limitan su distribuci on y las posi-bles causas que están detrás de esta a priori extinci on local. 4. Descargamos todos los registros de presencia de C. pamphilus y analizamos sus ten-dencias espaciales y temporales. Para identificar las variables climáticas que impul-san la distribuci on de esta mariposa en la Península Ibérica, realizamos un modelo de distribuci on de especies (SDM), combinando 600 modelos individuales produci-dos con 6 algoritmos. 5. Confirmamos que C. pamphilus no se ha observado en el sureste de la Península Ibérica desde 2008. La aridez fue el principal factor que limit o su distribuci on en nuestro SDM, siendo las zonas con alta aridez poco adecuadas para esta especie. 6. Nuestra hip otesis es que el polivoltinismo es el mecanismo que impulsa esta extinci on local, ya que la elevada aridez está provocando el agostamiento prema-turo de las plantas hospedadoras (Poaceae), impidiendo el desarrollo de la segunda y/o tercera generaci on de la mariposa. Aunque las especies generalistas son te oricamente más resistentes al cambio climático, otros rasgos como el polivolti-nismo pueden aumentar su vulnerabilidad y deben ser investigados más a fondo.
... Immature fleas are also highly sensi- tive to desiccation and, if relative humidity is too low, fleas will not complete development even when the temperature is favorable (Krasnov et al. 2001ab;Kreppel et al. 2016). These temperature thresholds and heat energy requirements play key roles in determining species ranges and abundance of insects (Andrewartha and Birch, 1986), and the expansion and contraction of insect ranges as local climates cool or warm is well documented (Parmesan et al. 1999). The Oropsylla species that occur on prairie dogs have not been colonized in laboratory settings, so the exact relationship between temperature and their development has not been determined. ...
Fleas are common ectoparasites of vertebrates worldwide and vectors of many pathogens causing disease, such as sylvatic plague in prairie dog colonies. Development of fleas is regulated by environmental conditions, especially temperature and relative humidity. Development rates are typically slower at low temperatures and faster at high temperatures, which are bounded by lower and upper thresholds where development is reduced. Prairie dogs and their associated fleas (mostly Oropsylla spp) live in burrows that moderate outside environmental conditions, remaining cooler in summer and warmer in winter. We found burrow microclimates were characterized by stable daily temperatures and high relative humidity, with temperatures increasing from spring through summer. We previously showed temperature increases corresponded with increasing off-host flea abundance. To evaluate how changes in temperature could affect future prairie dog flea development and abundance, we used development rates of O. montana (a species related to prairie dog fleas), determined how prairie dog burrow microclimates are affected by ambient weather, and combined these results to develop a predictive model. Our model predicts burrow temperatures and flea development rates will increase during the twenty-first century, potentially leading to higher flea abundance and an increased probability of plague epizootics if Y. pestis is present.
... As there is now undeniable evidence for contemporary climate change (IPCC, 2007), it is thought that most species will respond to this temperature increase through shifts in their geographic range (Garroway et al., 2011;Parmesan, 2006). For many species, they have sufficient resources to support populations beyond their originally occupied range, however, they are limited by other factors like climate (Parmesan et al., 1999). In these circumstances, climate warming can make new areas available by shifting climate systems, leading to species range shifts. ...
Climate change may potentially alter a species’ range distribution and thus the relationship between environmental temperatures and animal performance as a response to climate warming has become an important area of research. Two species of flying squirrel in North America, the southern flying squirrel (Glaucomys volans) and the northern flying squirrel (Glaucomys sabrinus) have undergone northward range shifts, with climate warming being the suspected driver. Because they are nocturnal and tree nesting, flying squirrels may be particularly susceptible to warmer temperatures, as they will experience the highest daily ambient temperatures during their resting phase. I used G. sabrinus as a study species to determine the effect of high temperatures on thermoregulation and energy use to test if thermal limits will contribute to range shifts. I measured metabolic rate and evaporative water loss under different ambient temperatures using flow-through respirometry and estimated the responses to high ambient temperatures in the field by measuring body temperature. I used climate data from Arrowsic, Bangor, and Presque Isle, Maine over recent decades to determine if temperature increases would correspond to the northward movement of flying squirrels in Maine. G. sabrinus did not show visible or physiological signs of heat stress during respirometry experiments, and an upper critical temperature was not reached at temperatures tested. Consistent daily rhythms in body temperature were observed in free-ranging flying squirrels, as predicted, and increased as ambient temperatures decreased. Additionally, high ambient temperatures were not likely to be a direct factor in northern flying squirrel range shifts, but that climate warming caused G. volans to move north and outcompete G. sabrinus.
... For example, arid and semi-arid zones are expanding [25] , the latitudinal limit of temperate forests has shifted poleward [26] and several vegetation types, as well as several species in particular, have migrated altitudinally in recent times [27] . Animal populations have also undergone important changes; for example, in Great Britain, 22 species of butterflies are reported to have expanded their home range towards colder latitudes [28] , while in Spain, 16 species of butterflies changed their altitudinal distribution (climbed almost 200 m), representing a considerable increase in their optimal habitat [29] . ...
Important modifications are occurring in temperate forests due to climate change; in polar latitudes their distribution area is increasing, while in tropical latitudes it is decreasing due to temperature increase and droughts. One of the biotic regulators of temperate forests are the debarking insects that cause the mortality of certain trees. These insects have increased in number, favored by climate change, and the consequences on forests have not been long in coming. In recent times in the northern hemisphere, the massive mortality of conifers due to the negative synergy between climate change and debarking insects has been evident. In Mexico, we have also experienced infestations by bark stripping insects never seen before; therefore, we are trying to understand the interactions between climate change, forest health and bark stripping insects, to detect the areas with greater susceptibility to attack by these insects and propose management measures to reduce the effects.
... Moreover, land-use change, water diversion, and environmental pollution are experiencing stress due to global climate change. Variation (increases and decreases) in water temperature due to climate change would modify the fundamental ecological process including migration of the aquatic species (Parmesan et al., 1999;Grabherr et al., 1994;Wiens, 2016). The temperature variations can be minimized by migrating aquatic species to a suitable place. ...
The aquatic ecosystem is prone to global climate change and pollution affecting aquatic animals, including fish. In light of the above, we experimented with delineate the role of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) along with selenium nanoparticles (Se-NPs) to enhance the thermal tolerance in Pangasianodon hypophthalmus reared under control or high temperature and arsenic (As + T) for 112 days. Se-NPs were synthesized using the green approach. Four experimental diets viz. EPA + DHA at 0.2, 0.4 and 0.6 % along with Se-NPs at 0.2 mg kg⁻¹ diet were formulated and prepared. End of the experiment (112 days), the thermal tolerance viz. CTmin (critical thermal minima) CTmax (critical thermal maxima), LTmin (lethal thermal minima) and LTmax (lethal thermal maxima) were determined. Supplementation of EPA + DHA along with Se-NPs noticeably improved the thermal tolerance of the fish reared under stress (As + T) and control condition. Oxidative stress such as superoxide dismutase, glutathione-s-transferase, catalase, glutathione peroxides and LPO were enhanced by As + T, whereas EPA + DHA at 0.4 % and Se-NPs reduced the oxidative stress. Further, acetylcholine esterase was inhibited by arsenic alone and concurrent with temperature but dietary supplementation significantly enhanced brain AChE activity. Exposure to arsenic and concurrent with a temperature significantly reduced the ATPase. Whereas supplementation of EPA + DHA at 0.4 % and Se-NPs enhanced the ATPase in liver and gill tissues. Arsenic bioaccumulation was also reduced with EPA + DHA at 0.4 % and Se-NPs. The present investigation concluded that EPA + DHA at 0.4 % and Se-NPs at 0.2 mg kg⁻¹ diet protects the P. hypophthalmus against arsenic pollution and thermal stress.
... Climate-induced range expansions are particularly well-recorded in insects (Hickling et al., 2006;Parmesan et al., 1999). In temperate climates, daylength serves as the main environmental cue for timing diapause, a state of seasonal dormancy helping insects survive winter and time reproduction to the summer (Denlinger, 2022). ...
Climate change allows species to expand polewards, but non‐changing environmental features may limit expansions. Daylength is unaffected by climate and drives life cycle timing in many animals and plants. Because daylength varies over latitudes, poleward‐expanding populations must adapt to new daylength conditions. We studied local adaptation to daylength in the butterfly Lasiommata megera, which is expanding northwards along several routes in Europe. Using common garden laboratory experiments with controlled daylengths, we compared diapause induction between populations from the southern‐Swedish core range and recently established marginal populations from two independent expansion fronts in Sweden. Caterpillars from the northern populations entered diapause in clearly longer daylengths than those from southern populations, with the exception of caterpillars from one geographically isolated population. The northern populations have repeatedly and rapidly adapted to their local daylengths, indicating that the common use of daylength as seasonal cue need not strongly limit climate‐induced insect range expansions. Many species that expand polewards as a result of climate change need to adapt to latitudinal differences in daylength because daylength guides life history decisions. We describe two parallel northward range expansions of a butterfly in Sweden and show experimentally that range margin populations at both expansion fronts have adapted locally to daylength. This has happened despite theory suggesting constraints to local adaptation at range margins and implies that the need to evolve new responses to daylength cues need not hinder range‐expansions.
... Preferential temperature and CO 2 ranges are speciesspecific and future environmental changes would affect the species differently [3]. Favoured climatic conditions hastened the rate of growth and development and lead to more generations per year and expand its geographical range [45]. Elevated temperature and CO 2 levels altered the biochemical components in leaves and thereby affecting the relationship between plants and herbivorous insects [12]. ...
The fall armyworm, Spodoptera frugiperda is a recent invasive significant pest of maize in India for the past three years. As, there are two strains reported in S. frugiperda, before proceeding for any studies, it is important to confirm whether the populations introduced belongs to ‘R’ strain or ‘C’ strain. PCR–RFLP technique was used to analyze the morphologically indistinguishable host associated strains. The present experiment was planned with PCR amplification of mitochondrial cytochrome oxidase I gene followed by restriction digestion with SacI and MspI enzymes. MspI digestion does not shows any restriction, whereas SacI digestion produced restriction fragments confirming the ‘R’ (rice) strain of S. frugiperda. Biochemical analysis of maize leaves revealed that with an increase in temperature and CO2 levels, there was an increase in carbohydrate, protein, proline, phenol, tannin, and carbon content but the reduction in C:N ratio, vitamin C, and chlorophyll content. The survival of fall armyworm decreased with the progress of age at elevated temperature and CO2 levels. The increased fertility and population outburst were recorded up to 34 °C and 490 ppm. These results signifies that the temperature and CO2 levels above a threshold is detrimental to fall armyworm.
... Further, climate change is known to cause many animal species to change their distributions with many demonstrating elevation or latitudinal range shifts (Cristofari et al., 2018;Crozier, 2004;Kwon et al., 2014;McCain & Garfinkel, 2021). This phenomenon is well established in many volant species such as birds (Hitch & Leberg, 2007) and butterflies (Crozier, 2004;Konvicka et al., 2003;Parmesan et al., 1999). Dung and Carabidae beetles have also demonstrated upward elevational range shifts (Herzog et al., 2013;Larsen, 2012;Menéndez et al., 2014;Ouisse et al., 2020) and there has been evidence of a poleward range expansion of Carabidae from Europe, Israel and the UK (Drees et al., 2011;Hickling et al., 2006). ...
Concerning declines in insect populations have been reported from Europe and the United States, yet there are gaps in our knowledge of the drivers of insect trends and their distribution across the world. We report on our analysis of a spatially extensive, 14‐year study of ground‐dwelling beetles in four natural forest biomes spanning Japan's entire latitudinal range (3000 km). Beetle species richness, abundance and biomass declined in evergreen coniferous forests but increased in broadleaf‐coniferous mixed forests. Further, beetles in evergreen coniferous forests responded negatively to increased temperature and precipitation anomalies, which have both risen over the study's timespan. These significant changes parallel reports of climate‐driven changes in forest tree species, providing further evidence that climate change is altering forest ecosystems fundamentally. Given the enormous biodiversity and ecosystem services that forests support globally, the implications for biodiversity change resulting from climate change could be profound.
... The alarming headlines are, however, confounded by other studies such as MacGregor et al. (2019) who report 'increasing biomass between 1967 and 1982, followed by gradual decline from 1982 to 2017, with a 2.2-fold net gain in mean biomass between the first (1967)(1968)(1969)(1970)(1971)(1972)(1973)(1974)(1975)(1976) and last decades (2008-2017) of monitoring'. There are also numerous examples of range expansion, including: birds (Massimino et al. 2015); some Diptera (Ball and Morris 2021a; Ball 2003, 2004); Lepidoptera (Parmesan et al. 1999;Franco et al. 2006;Thomas et al. 2006;Gillingham et al. 2015) and Odonata (Hickling et al. 2005;Mason et al. 2015). Range contraction has been far more difficult to detect (Pateman and Hodgson 2015) even though there are numerous modelling studies that predict range contraction (e.g. ...
We describe significant range changes in Leucozona glaucia (Linnaeus, 1758) during the period 1980 to 2021, using two different techniques. Relative frequency of the species corrected for recording effort was estimated using FRESCALO and species distribution models were fitted using Maxent. The distributions estimated for two spans of years at the beginning and end of this period were compared. Both methods suggest that the range of L. glaucia has changed substantially. It has contracted in southeast and eastern England but has expanded in northwest Scotland and perhaps also more generally in western Britain. The reasons for these changes are as yet unconfirmed, but we suspect that the principal driver is increasingly frequent periods of water and heat stress. We hypothesise that these stresses affect the larval stages.
... Butterflies have served as a key model system for studies of evolution, mimicry, and the expression of color [2][3][4] , visual ecology and learning 5 , meta-population theory 6 , biological associations, such as with hostplants, and networks 7,8 and migration dynamics 9 . Furthermore, in an increasingly changing world, butterflies have served as model organisms to study the effects of global change processes on ecological communities [10][11][12] , and the cultural importance of butterflies is also noteworthy 13 . For instance, butterflies figure prominently in Hopi culture and pottery 14 . ...
Here, we present the largest, global dataset of Lepidopteran traits, focusing initially on butterflies (ca. 12,500 species records). These traits are derived from field guides, taxonomic treatments, and other literature resources. We present traits on wing size, phenology,voltinism, diapause/overwintering stage, hostplant associations, and habitat affinities (canopy, edge, moisture, and disturbance). This dataset will facilitate comparative research on butterfly ecology and evolution and our goal is to inspire future research collaboration and the continued development of this dataset.
... Durante el desarrollo del estudio, los autores pudieron confirmar para Tierras Altas, Chiriquí, la presencia de M. opercularis y A. stimulea; mientras que, para tierras bajas de Panamá, se recibieron reportes de Megalopyge lanata Stoll, 1780 asociada a aguacate y mango de traspatio en las provincias de Panamá, Veraguas, Herrera, Los Santos, Coclé, Colón, Bocas del Toro y Chiriquí, del género Phobetron (Limacodidae) en Panamá y Chiriquí y del género Acharia en Panamá Oeste, Panamá y Chiriquí (Figura 2). Según Parmesan et al. (1999), el incremento de la temperatura como consecuencia del cambio climático es responsable de la expansión de varias especies de insectos como los Lepidoptera, hacia mayores altitudes y hacia los polos, además de ocurrir posibles cambios en la fenología estacional. ...
The objective of this study was to identify Lepidoptera stinging larvae found in plots with horticultural crops in
Cerro Punta, Chiriquí, Panama and to confirm the possible symptoms caused by erucism and lepidopterism.
About 16 random samplings were carried out during 14 and a half months, in plots with crops, surrounding
vegetation and infrastructure. Photographs were taken and samples were collected for processing in the
laboratory. Specialized literature was consulted for identification. A survey of 33 people affected by erucism or
lepidopterism was carried out. According to the results, the larvae found on the crops corresponded to
Leucanella hosmera (Schaus, 1941) (Saturniidae), Halysidota tessellaris (Smith, 1797) (Erebidae), Acharia
stimulea (Clemens, 1860) (Limacodidae) and an adult specimen of Megalopyge opercularis (Smith, 1797)
(Megalopygidae) was also found on a wall. In wild vegetation, L. hosmera and possibly Automeris pallidior
Draudt, 1929 (Saturniidae) larvae were found feeding on Faramea occidentalis (L.) A. Rich (Rubiaceae). The
survey reflected burning, pain and inflammation as frequent symptoms due to erucism or lepidopterism in
93.9%, requiring medical attention in 18.18% of cases. In conclusion, five species of stinging larvae associated
with horticultural crops were identified in Cerro Punta, which represent a potential health risk.
Keywords: Erucism; horticultural crops; caterpillars; Lepidoptera; stinging larvae.
... 12 Hence, determination of ecological tolerance allows for better prediction of pest species biogeographical patterns. 12 Although a poleward shift in species distribution has been predicted with climate warming, 13,14 tropical regions nevertheless remain vulnerable to pest insect outbreaks relative to temperate regions owing to optimal temperature and food resources. 15 Thus, predictive models should also extend to tropical areas given their vulnerability to new invasions. ...
Background:
Climate warming presents physiological challenges to insects, manifesting as loss of key life-history fitness traits and survival. For interacting host-parasitoid species, physiological responses to heat stress may vary thereby potentially uncoupling trophic ecological relationships. Here, we assessed heat tolerance traits and sensitivity to prevailing and future maximum temperatures for cereal stemborer pests, Chilo partellus, Busseola fusca and Sesamia calamistis and their endo-parasitoids, Cotesia sesamiae and Cotesia flavipes. We further used the machine learning algorithm, Maximum Entropy (MaxEnt), to model current and potential distribution of these species.
Results:
The mean critical thermal maxima (CTmax ) ranged from 39.5±0.9° C - 44.6±0.6° C and 46.8±0.7° C- 48.5±0.9° C for parasitoids and stemborers, with C. sesamiae and C. partellus exhibiting the lowest and highest CTmax respectively. From the present climate to 2050s scenario, parasitoids recorded significant reduction in warming tolerance than their hosts. Habitat suitability for all stemborer-parasitoid species was spatially heterogeneous under current and future climatic scenarios. Cotesia sesamiae C. flavipes and B. fusca exhibited significant habitat loss while C. partellus and S. calamistis showed a significant habitat gain under future 2050s predictions. Model metrics based on mean area under the curve ranged from 0.72 to 0.84 for all species, indicating good predictive performance of the models.
Conclusion:
These results suggest C. sesamiae and C. flavipes may face survival constraints or extirpation than their pest hosts when environmental temperature reaches their upper thermal limits earlier, likely reducing pest regulation through density-mediated effects. The results demonstrate potential destabilisation of stemborer-parasitoid trophic systems potentially compromising biocontrol efficacy under climate warming. This article is protected by copyright. All rights reserved.
... A study on 35 species of European butterflies (non-migratory) and the result showed that 63% of species have shifted their geographical range towards the north by 35 to 240 km and only 3% towards the south. (Parmesan et al. 1999). Shifting of range have been observed in forest geometrid moths such as Operophtera brumata (L.) (Lepidoptera: Geometridae), and Epirrita autumnata (Borkh.) ...
Climate change has substantial impact on insect species diversity and their distribution and poses a great threat to human food security by reducing agricultural production and productivity globally. The rise in earth's temperature, elevated carbon dioxide and change in the frequency of rainfall patterns and distribution of precipitation pattern are three major components of global climate change that has been affected insect pest dynamics in several ways. Rice is the foremost essential cereal crop and half of the worlds' population depends on it as a staple food. But its production remained on the lower side due to biotic stresses. Changes in climate affect the insect pests of rice in terms of expansion in geographical range, increased or decreased number of generations, growth and reproduction ability, fecundity, interspecific and tritrophic interaction, increased frequency of vector-borne diseases, and reduced effectiveness of biocontrol agents. Several adaptive management practices including modified integrated pest management tactics, monitoring of insect population and use of web-based modelling tools may be implemented to deal with the changing status of pest population owing to climate change.
... Deutsch et al. (2008) suggested that many insect species may become extinct in the tropical region with further rise in global temperature as they are already living at the maximum tolerable temperatures. It is predicted that by the end of 21 st century the tropical and subtropical regions of Asia and Africa will witness unusual seasonal average temperatures Naylor 2009, Neumeister, 2010) while present tropical insect species are predicted to extend their geographical area to presently colder areas, where climatic factors are going to be more suitable due to global warming (Parmesan et al., 1999;Paulson, 2001). ...
Global average temperature is on the rise and in the past century we witnessed a temperature rise of 0.6ºC. Insects share more than 70% of all known fauna present on this earth and present in every terrestrial habitat and due to their poikilothermic nature, they are very sensitive to the climate. So, any change in their surrounding climate can have havoc effects on them. The probable effects could result in their increase numbers, distribution range, infestation rate, tritrophic interaction, pollination pattern and on their management. Therefore, this chapter gives an overview of the likely effects of climate change on insect population of agricultural importance.
... The effects of climate change were well pronounced and prominent in the biodiversity, such as the early onset of phenological events at Boston's Arnold arboretum from 1980 to 2002 (Primack et al., 2004), shifting of the British bird and European butterfly species (Parmesan et al., 1999;Thomas & Lennon, 1999) towards the north, a decline in the coral reef population because of the thermal stress (Hoegh-Guldberg, 2011). Climate Change is likely to have a wrecking effect on species distribution, which limits the adaptive capabilities of species to their environment. ...
Agroforestry, a sustainable land use practice adopted as a strategy under Kyoto Protocol, plays a crucial role to mitigate the inevitable climate change with a promising potential of carbon sequestration in their biomass and utilization of their numerous resource. Agroforestry is crucial for reducing greenhouse gas emissions, sustaining livelihoods, and partial solutions for biodiversity conservation. Worldwide, agroforestry is practiced by more than 1.2 billion people, on around 1 billion hectares (ha) of land area, while in India, around 25.32 million hectares area comes under agroforestry. Agroforestry system is the enhancement of overall farm productivity, soil enrichment through litter fall, above and below ground carbon sequestration, maintaining environmental services. Different agroforestry systems are adapted at the global level and periodic monitoring and estimation of area under agroforestry, monitoring of tree and soil carbon stocks is still a challenging task due to the lack of uniform methodology. The review analyzes the potential of agroforestry systems for climate adaptation and mitigation as well as their implications for the livelihood of human well-being.
... The effects of climate change were well pronounced and prominent in the biodiversity, such as the early onset of phenological events at Boston's Arnold arboretum from 1980 to 2002 (Primack et al., 2004), shifting of the British bird and European butterfly species (Parmesan et al., 1999;Thomas & Lennon, 1999) towards the north, a decline in the coral reef population because of the thermal stress (Hoegh-Guldberg, 2011). Climate Change is likely to have a wrecking effect on species distribution, which limits the adaptive capabilities of species to their environment. ...
Agroforestry, a sustainable land use
practice adopted as a strategy under Kyoto Protocol,
plays a crucial role to mitigate the inevitable climate
change with a promising potential of carbon sequestration in their biomass and utilization of their numerous resource. Agroforestry is crucial for reducing
greenhouse gas emissions, sustaining livelihoods, and
partial solutions for biodiversity conservation. Worldwide, agroforestry is practiced by more than 1.2 billion people, on around 1 billion hectares (ha) of land
area, while in India, around 25.32 million hectares
area comes under agroforestry. Agroforestry system is the enhancement of overall farm productivity, soil enrichment through litter fall, above and below
ground carbon sequestration, maintaining environmental services. Diferent agroforestry systems are
adapted at the global level and periodic monitoring
and estimation of area under agroforestry, monitoring of tree and soil carbon stocks is still a challenging task due to the lack of uniform methodology. The
review analyzes the potential of agroforestry systems
for climate adaptation and mitigation as well as their implications for the livelihood of human well-being.
... However, the period until 2100 is comparably much shorter and the velocity of changes may be too fast to allow adaptive evolution (Parmesan 2006). Moreover, the tropical phylogenetic pattern also suggests that butterflies have a low tolerance for strong climate change, highlighting the risks associated with those processes (Parmesan et al. 1999). ...
Climate change is currently considered one key threat to biodiversity. Species with a restricted distribution possibly will be more affected than those with wide ranges. Climate change can potentially affect both herbivores and their host plants and reduce their geographical ranges. The nature and intensity of their responses, however, may not necessarily match. We investigated the synergistic effects of climate change on two Neotropical butterfly species and their respective host plants at the end of twenty-first century. The species selected contrast in distribution extent, feeding habits and conservation status: Battus polystictus is widespread, oligophagous and common and Parides ascanius has a restricted distribution, is monophagous and is listed as vulnerable in the IUCN red list. Maps of the potential distribution of the butterflies and their host plants, as well as maps showing the changes in the ranges, in overlap area and direction of shifts were produced. Under forecasted climate change, all ranges and interaction areas decreased and the impacts were proportional to the intensity of change in future scenarios, either when compared all together or pairwise (p < 0.001). Based in our results estimation of climatically suitability, the monophagous butterfly with restricted distribution did suffer more severely these effects than the widespread generalist species. We did not anticipate, however, the possible strength of the predicted effects. Under the conditions modelled, P. ascanius would probably find no suitable conditions for occurrence, irrespectively of its host plant, and might go extinct. B. polystictus, on the other hand, suffered marked decreases in suitable area (46% for RCP4.5 and 91% for RCP8.5) and dramatic southward shifts (> 1439 km for RCP4.5 and > 1956 km for RCP8.5) on its range. This effect is further worsening because although most host plants are also much affected by the changes, the shift in their ranges is on average much smaller and each species responded in subtly different ways to the changing conditions, so that most of their future range may be spatially incompatible with the B. polystictus. We propose that the extinction risk of P. ascanius should be adjusted to critically endangered and point that species interactions and climate change must be accounted for in conservation planning.
Implications for insect conservation
The assessment carried out in this study contributes to the knowledge of climate change scenarios of butterfly species correlated with their host plants until the end of this century. These results can propose priority sites for conservation efforts like contribute to change status of P. ascanius to critically endangered, actually listed as vulnerable on the IUCN red list.
... As climate warms or cools, the conditions suitable for the persistence of given species shifts across the surface of the Earth, prompting species to move as they attempt to track preferred climatic conditions [32,41,42]. Both global and local climates are subject to processes operating across temporal scales and have been shown to drive changes in species' distributions (e.g., in order of lengthening temporal scale [43][44][45]). ...
Geographic ranges are a fundamental unit of biogeography and macroecology. Increasingly, paleontologists and ecologists alike are reconstructing geographic ranges of species from fossils, in order to understand the long-term processes governing biogeographic and macroevolutionary patterns. As these reconstructions have become increasingly common, uncertainty has arisen over the equivalency of paleo-ranges and modern ranges. Here, we argue geographic ranges are time-averaged at all temporal scales, and reflect the biotic and abiotic processes operating across the equivalent range of time and space scales. This conceptual framework integrates the study of geographic ranges reconstructed using modern and ancient data, and highlights the potential for ranges to illuminate processes responsible for diversity patterns over intervals spanning days to tens of millions of years of Earth history.
... Communicated by Konrad Fiedler. For many decades, butterflies have figured as a model group for understanding the impact of weather and climate change on insect populations (Pollard 1988;Parmesan et al. 1999;Devictor et al. 2012). Various studies have shown how year-to-year population changes are influenced by weather (Roy et al. 2001;Boggs and Inouye 2012) and also how ECEs can lead to population crashes and/or explosions (Palmer et al. 2017;McDermott Long et al. 2017). ...
Understanding population responses to environmental conditions is key in the current context of climate change and the extreme climatic events that are threatening biodiversity in an unprecedented way. In this work, we provide a framework for understanding butterfly population responses to weather and extreme climatic seasons by taking into account topographic heterogeneity, species' life-cycles and density-dependent processes. We used a citizen-science database of Mediterranean butterflies that contains long-term population data (28 years) on 78 butterfly species from 146 sites in the Mediterranean mesic and alpine climate regions. Climatic data were obtained from 93 meteorological stations operating during this period near the butterfly sites. We studied how seasonal precipitation and temperature affect population growth while taking into account the effects of density dependence. Our results reveal (i) the beneficial effects of winter and spring precipitation for butterfly populations, which are most evident in the Mediterranean region and in univoltine species, and mainly affect the larval stage; (ii) a general negative effect of summer rain in the previous year, which affects the adult stage; and (iii) a consistent negative effect of mild autumns and winters on population growth. In addition, density dependence played a major role in the population dynamics of most species, except for those with long-term negative population trends. Our analyses also provide compelling evidence that both extreme population levels in previous years and extreme climatic seasons in the current year provoke population crashes and explosions, especially in the Mediterranean mesic region.
As mean temperatures increase and heatwaves become more frequent, species are expanding their distributions to colonise new habitats. The resulting novel species interactions will simultaneously shape the temperature-driven reorganization of resident communities. The interactive effects of climate change and climate change-facilitated invasion have rarely been studied in multi-trophic communities, and are likely to differ depending on the nature of the climatic driver (i.e. climate extremes or constant warming). We recreated under laboratory conditions a host-parasitoid community typical of high-elevation rainforest sites in Queensland, Australia, comprising four Drosophila species and two associated parasitoid species. We subjected these communities to climate change in the form of either heatwaves or constant warming, in combination with an invasion treatment involving a novel host species from lower-elevation habitats. The two parasitoid species were sensitive to both warming and heatwaves, while the demographic responses of Drosophila species were highly idiosyncratic, reflecting the combined effects of thermal tolerance, parasitism, competition, and facilitation. After multiple generations, heatwaves (but not constant warming) promoted the establishment of low-elevation species in upland communities. The introduction of this invading species correlated negatively with the abundance of one of the parasitoid species, leading to cascading effects on its hosts and their competitors. Our study, therefore, reveals differing, sometimes contrasting, impacts of extreme temperatures and constant warming on community composition. It also highlights how the scale and direction of climate impacts could be further modified by range-expanding species within a bi-trophic community network.
Species are altering their ranges as a response to climate change, but the magnitude and direction of observed range shifts vary considerably among species. The ability to persist in current areas and colonize new areas plays a crucial role in determining which species will thrive and which decline as climate change progresses. Several studies have sought to identify characteristics, such as morphological and life-history traits, that could explain differences in the capability of species to shift their ranges together with a changing climate. These characteristics have explained variation in range shifts only sporadically, thus offering an uncertain tool for discerning responses among species. As long-term selection to past climates have shaped species’ tolerances, metrics describing species’ contemporary climatic niches may provide an alternative means for understanding responses to on-going climate change. Species that occur in a broader range of climatic conditions may hold greater tolerance to climatic variability and could therefore more readily maintain their historical ranges, while species with more narrow tolerances may only persist if they are able to shift in space to track their climatic niche. Here, we provide a first-filter test of the effect of climatic niche dimensions on shifts in the leading range edges in three relatively well-dispersing species groups. Based on the realized changes in the northern range edges of 383 moth, butterfly, and bird species across a boreal 1,100 km latitudinal gradient over c. 20 years, we show that while most morphological or life-history traits were not strongly connected with range shifts, moths and birds occupying a narrower thermal niche and butterflies occupying a broader moisture niche across their European distribution show stronger shifts towards the north. Our results indicate that the climatic niche may be important for predicting responses under climate change and as such warrants further investigation of potential mechanistic underpinnings.
How species respond to climate change may impact their extinction probability. Here we link climatology and ecology to tackle a globally important conservation question. For sea turtles, there are concerns that climate warming will cause both the feminization of populations as well as reduced hatchling survival. For 58 nesting sites across the world spanning all seven sea turtle species, we investigated whether warming might be avoided by shifts in nesting phenology to a cooler part of the year. We show that even with the most extreme phenological shift that has been reported to date—an 18-day advance in nesting per °C increase in sea surface temperature (SST)—temperatures will continue to increase at nesting sites with climate warming. We estimate that SST at nesting sites will rise by an average of 0.6°C (standard deviation = 0.9°C, n = 58) when we model a 1.5°C rise in SST combined with a best-case-scenario shift in nesting. Since sea turtles exhibit temperature-dependent sex determination, these temperature rises could lead to increasingly female-biased sex ratios as well as reduced hatchling production at sites across the world. These findings underscore concerns for the long-term survival of this iconic group.
While some species rapidly decline, compromising vital ecosystem services, others are stable or even increasing in abundance. We studied shifts in species richness and abundance of moths over five decades in Central Sweden and examined whether and how changes were associated with phenotypic traits. We combined information from captures in a light trap in historical time (the 1970s) and contemporarily (2019) with provincial colonisation records. Both community species richness and the abundance of moths increased between the time periods. A large fraction (38%) of the 410 species were not present in both periods, 101 species had colonised the area (an estimated influx of about 2.5 new species per year), and 51 species had disappeared (an estimated local extinction rate of about 1.16 species per year). Abundance increased with an increasing number of host plants and with increasing colour pattern variation. The composition of the community shifted towards species characterised by smaller wingspan and larger ranges. The functional trait variability of the moth community was homogenised from the historical to the contemporary period, in line with reports from other species communities in modern landscapes. However, our finding of a concomitant increase in species richness and total abundance differs from the results of many recent studies of insect communities in other geographic regions.
Implication for insect conservation
We conclude that the entire boreal moth fauna is undergoing a substantial biogeographical shift, changing to the moth species historically occurring at more southern latitudes. The alterations in species composition, overall abundance, and community-wide trait distribution described here may cascade up and down in the ecosystem because moths are important pollinators, herbivores, and prey.
Aim
Species are expected to disperse poleward in response to climate change. For species that are endemic to the high latitudes, this implies that many in the future would face a “no‐where‐to‐go” situation as they are currently occupying the northernmost portion of the continent. Further, because endemism may arise from a combination of physical barriers, climate and geological history, the persistence of many species may require spatial matching of multiple environmental factors within a limited dispersal space. Thus, it is not clear how endemic species might spatially adjust their distributions in response to climate change and whether there are future climate change refugia for these species.
Location
Northwest North America.
Taxa
Plants.
Time Period
Current and the future (2040).
Methods
We used ensemble bioclimatic models to evaluate drivers and directional patterns of future change in the distributions of 66 North American Beringian and amphi‐Beringian species currently occurring in Alaska and the Yukon. We explored the spatial pattern of species richness, losses and climate change refugia across the region.
Results
More than 80% of the species showed northward shifts in their latitudinal centroids under intermediate warming and are expected to shift their range northward by more than 140 km on average by 2040. Additionally, more than 60% were projected to experience range contractions and up to 20% of the species would have the potential to expand their ranges by more than 100%.
Main Conclusions
Suitable habitat for endemic species in northwest North America is expected to decline significantly, especially for species occupying the Arctic tundra. Although the models identified several potential refugia from future climate change, especially at high latitude and elevation, whether the species would be able to colonize new habitats on their own and/or capitalize sufficiently on in situ refugia remains a pertinent conservation question.
Climate change impacts emerging infectious disease events through multiple mechanisms, but the influence it exerts through driving host range shifts has been little explored. For instance, range shifts may affect pathogen transmission by altering the connectivity of host populations. Additionally, range expanding hosts and pathogens will have different physiological responses to the suites of novel, challenging conditions they are exposed to, influencing infection outcomes. We studied the fungal pathogen Batrachochytrium dendrobatidis (Bd) on three anuran amphibians in the Cordillera Vilcanota, Peru: Pleurodema marmoratum, Telmatobius marmoratus, and Rhinella spinulosa. There, these species have undergone a climate-driven range expansion into recently deglaciated habitat to become both the highest elevation amphibians and the highest elevation cases of Bd infection globally. We analyzed Bd genetics, infection metrics, and sublethal impacts along the colonization front (3,900—5,400 m asl) to explore how elevational range expansion affected host-pathogen dynamics. Amphibian range shifts have enabled new connectivity across the once continuously glaciated Cordillera Vilcanota, but genetic evidence suggests that Bd disperses so frequently and extensively that this novel connectivity has not contributed significantly to overall Bd dispersal. Although amphibians have not escaped Bd infection outright through upslope expansion in the Cordillera Vilcanota, Bd growth does appear to be constrained at the highest reaches of the Vilcanota. We present evidence that Bd infection has different sublethal costs for amphibians at the new elevations they have colonized, but whether the costs are mitigated or exacerbated by extreme elevation may be moderated by amphibian microhabitat use.
Climate change is leading to a species redistributions. In the tundra biome, many shrub species are expanding into new areas, a process known as shrubification. However, not all tundra shrub species will benefit from warming. Winner and loser species (those projected to expand and contract their ranges, and/or those that have increased or decreased in cover over time), and the characteristics that may determine success or failure, have not been fully identified. Here, we investigate whether current range sizes are related to plant trait values and intraspecific trait variation by combining 17,921 trait records and distribution data from 62 shrub species across three continents (>30 degrees north). In addition, we determine which traits are associated with species projected by species distribution models to expand or contract their ranges under climate change, and species that have undergone past cover changes over time. Winner and loser shrub species identified from projected range shifts generally differed from those identified from observed past cover change. We found that greater variation in seed mass and specific leaf area were related to larger projected range shifts. Projected winner species generally had greater seed mass values than ‘no change’ and loser species. However, contrary to our expectations, traits’ values and variation were not consistently related to current and projected ranges, and depended upon the future climate scenarios considered in range projections. There were no clear relationships either between cover change over time and trait values or variation. Overall, our findings indicate that abundance changes and projected range shifts will not lead to directional modifications in shrub trait composition or variation with future warming, since winner and loser species share relatively similar trait spaces based on commonly measured traits. Future research could investigate other morpho-physiological traits underpinning climatic preferences, which might better predict future range and abundance changes.
INTRODUCTION
Animals inhabit environments that are rapidly changing due to anthropogenic activities, such as the destruction and fragmentation of habitats, the introduction of exotic species and the alteration of local and global climate regimes. These changes are stretching the capacity of animals to cope, with conditions potentially outside the bounds of those experienced over the recent evolutionary history of the species. For managers of protected areas and endangered populations to respond in time to the threats posed by changing environments, these threats must be recognized early on, when still relatively benign, so as to be able to mitigate or counteract the adverse consequences of the altered environment. Coping takes place most immediately through behavioral responses, perhaps followed at a later stage by adjustments in physiology, and maybe over generational scales by shifts in morphology. This means that changes in animal behavior are potentially sensitive indicators that can provide the necessary early warning. Such behaviors must be documented in such a way that the changes will be revealed. In Chapter 11, Kotler et al. describe in detail how managers can use the behavior of animals as an indicator for their population's status and as a monitoring tool for the success of management programs aimed to assist these populations. However, behavioral indicators can tell us even more.
Animals in the wild do not live their life in isolation. They are a part of a complex ecosystem that includes many different species as well as various abiotic features. All species in a given system interact, to some extent, either directly or indirectly. There are many types of biological interactions between species: The most common ones are competition (either direct competition through interference or indirect through the utilization of shared resources), predation, parasitism and mutualism (e.g. pollination or seed dispersal). In addition, animals interact with their abiotic environment. The environment provides resources such as food and shelter, as well as constraints that may limit the behavior of animals (e.g. barriers that limit movement, the chemical composition of the water that can affect the behavior of aquatic species or noise that can limit communication between individuals). There is a constant feedback between animals and their environment, which, depending on existing conditions, may be either positive or negative.
Climate change represents one of the greatest challenges facing human society. It has great impact on agricultural production, as a whole. It significantly influences biology, ecology, occurrence, and distribution of plant pests (insects, pathogens, and weeds), pest–host plant interactions, and activity of natural enemies. Indirectly, altered climate conditions have impacted the efficacy of control measures applied within Integrated Pest Management (IPM) programmes. Some of the IPM techniques, primarily plant resistance/tolerance and biocontrol measures are highly susceptible to the fluctuations in the environment. Therefore, there is a constant need to evaluate the efficacy of IPM techniques under different and altered environmental conditions and to adapt IPM to changing climate. To address this challenge, climate‐smart pest management (CSPM) approach has been developed. It provides more focus on management of various plant pests in the context of climate change, and involves all key actors in the production chain: farmers, research institutes, advisory services, and governmental bodies.
The impressive diversity of life forms on the planet Earth and their distribution over the globe have always aroused the wonder and curiosity of many scientists and enthusiast naturalists. The term biodiversity, or biological diversity, indicates precisely all of these life forms. The history of biodiversity coincides with the history of life on Earth, life that originated in all probability about 3.7 billion years ago, certainly in the water, perhaps in deep hot springs (see Fig. 1.1). We must not forget that the earth’s crust and atmosphere, as we know them now, have been moulded by the evolving organisms. The first living beings inhabited anoxic environments (originally there was virtually no oxygen in both water and the atmosphere). The evolution of organisms capable of performing photosynthesis allowed the accumulation of oxygen and the development of an atmosphere like the one we experience today.
Aim
Biodiversity loss is a major global challenge. While population trends of vertebrates are well documented, insect declines have not been sufficiently studied. We aim to identify changes in Orthoptera assemblages and the underlying drivers with a focus on land‐use and climate change.
Location
Central Europe.
Time period
2018 to 2020.
Methods
We resurveyed 199 study sites in which Orthoptera assemblages had been recorded between 1986 and 1999.
Results
Our results show a significant increase in species per site (α‐diversity), but simultaneously a homogenization of Orthoptera assemblages (decreasing Sorensen's β‐diversity). Highly mobile species significantly increased in site occupancy compared to species with low mobility. Some Orthoptera species showed significant altitudinal range shifts, including species with positive trends (i.e. expansion to higher altitudes) and negative trends (i.e. extinction at lower altitudes). Abandonment of extensively used grassland sites and the associated afforestation had negative effects on Orthoptera, underlining the importance of extensive grassland management. Protected areas had a high efficacy for conservation as trends in site occupancy were generally more positive in protected areas than in unprotected sites.
Main conclusions
Our results provide insights into the patterns and drivers of orthopteran assemblage turnover, including major effects of agricultural land‐use change and climate change. These results are essential for implementing and adapting conservation action, as they show that traditional land‐use practices, protected areas and reduction of nitrogen input are important to preserve Orthoptera. The results also show that climate change is driving both range expansion and retraction of species. Therefore, insect monitoring is critical to understanding insect population trends and implementing the necessary actions.
Most of our understanding of the effects of climate warming on insect body size comes from laboratory experiments. Whether these studies predict patterns in nature is largely unknown. Here we examine the relevance of laboratory warming experiments for wild populations of the butterfly Pieris rapae. We tested two predictions: (i) butterflies reared at warmer temperatures in the laboratory should attain smaller adult sizes and have reduced flight ability, and (ii) in nature, this trait combination should lead to smaller butterflies visiting fewer flowers and accumulating less pollen. Overall, we found that warm‐reared butterflies were indeed smaller and flew more slowly compared to colder‐reared conspecifics. Additionally, wild‐caught small butterflies carried fewer, and a lower diversity of pollen grains compared to larger butterflies. Our warming experiments thus largely predicted pollen collection patterns in wild P. rapae. This study demonstrates that increased temperatures will likely have important consequences for butterfly‐plant interactions in nature. Here we used a laboratory experiment to demonstrate that warmer rearing temperatures reduced body size and fight speed in the widespread butterfly Pieris rapae. We also found that in nature, P. rapae of equivalent size to those reared in warmed laboratory conditions carried less pollen and visited fewer flower types compared to larger‐sized butterflies. Our study suggests that insect body size changes due to ongoing warming will have important effects on plant–pollinator interactions.
Analysis of the global mean surface air temperature has shown that its increase is due, at least in part, to differential
changes in daily maximum and minimum temperatures, resulting in a narrowing of the diurnal temperature range (DTR). The analysis,
using station metadata and improved areal coverage for much of the Southern Hemisphere landmass, indicates that the DTR is
continuing to decrease in most parts of the world, that urban effects on globally and hemispherically averaged time series
are negligible, and that circulation variations in parts of the Northern Hemisphere appear to be related to the DTR. Atmospheric
aerosol loading in the Southern Hemisphere is much less than that in the Northern Hemisphere, suggesting that there are likely
a number of factors, such as increases in cloudiness, contributing to the decreases in DTR.
A framework is presented to quantify observed changes in climate within the contiguous United States through the development and analysis of two indices of climate change, a Climate Extremes Index (CEI) and a U.S. Greenhouse Climate Response Index (GCRI). The CEI is based on an aggregate set of conventional climate extreme indicators, and the GCRI is composed of indicators that measure changes in the climate of the United States that have been projected to occur as a result of increased emissions of greenhouse gases. The CEI supports the notion that the climate of the United States has become more extreme in recent decades, yet the magnitude and persistence of the changes are not large enough at this point to conclude that the increase in extremes reflects a nonstationary climate. Nonetheless, if impacts due to extreme events rise exponentially with the index, then the increase may be quite significant in a practical sense. Similarly, the positive trend of the U.S. GCRI during the twentieth century is consistent with an enhanced greenhouse effect. The increase is unlikely to have arisen due to chance alone (there is about a 5% chance). Still, the increase of the GCRI is not large enough to unequivocally reject the possibility that the increase in the GCRI and anticipated changes says little about the sensitivity of the climate system to the greenhouse effect. Both indices increased rather abruptly during the 1970s, a time of major circulation changes over the Pacific Ocean and North America. 37 refs., 14 figs., 4 tabs.
We found several rare UK butterflies to be restricted to relatively large and non-isolated habitat patches, while small patches and those that are isolated from population sources remain vacant. These patterns of occurrence are generated by the dynamic processes of local extinction and colonization. Habitat patches act as terrestrial archipelagos in which long-term population persistence, and hence effective long-term conservation, rely on networks of suitable habitats, sufficiently close to allow natural dispersal.
Although psychophysical evidence for object-based attention has been reported, corresponding studies with event-related potentials (ERPs) are scarce. Here subjects were presented with perceptual fields containing two superimposed objects (transparent surfaces generated by two sets of dots in rigid rotation around fixation, each set of a different color and direction of motion) or only one object (the same dots but either at rest or all rotating in the same direction). Brief (150-msec) rectilinear displacements affected either of the sets at random ISIs of 350 to 550 msec. Attention was directed to one set of dots, guided by color, in order to discriminate the direction of their displacement. Motion-onset ERPs elicited by these displacements were compared for attended and unattended dots. When the perceptual field consisted of two objects, strong suppression of P1 and N1 was obtained in the ERPs associated with the unattended object. No suppression was found with the field containing a single object, although an enhanced selection negativity was found in ERPs associated with attended dots (selected by color). Since the two objects occupied the same region of visual space, the suppression of P1/N1 cannot be explained by the space-based mechanisms but is consistent with object-based attentional selection at early stages of vision. The results highlight the role of perceptual organizations in enabling alternative attentional mechanisms.
We studied the response of single units to moving random dot patterns in areas V1 and MT of the alert macaque monkey. Most cells could be driven by such patterns; however, many cells in V1 did not give a consistent response but fired at a particular point during stimulus presentation. Thus different dot patterns can produce a markedly different response at any particular time, though the time averaged response is similar. A comparison of the directionality of cells in both V1 and MT using random dot patterns shows the cells of MT to be far more directional. In addition our estimates of the percentage of directional cells in both areas are consistent with previous reports using other stimuli. However, we failed to find a bimodality of directionality in V1 which has been reported in some other studies. The variance associated with response was determined for individual cells. In both areas the variance was found to be approximately equal to the mean response, indicating little difference between extrastriate and striate cortex. These estimates are in broad agreement (though the variance appears a little lower) with those of V1 cells of the anesthetized cat. The response of MT cells was simulated on a computer from the estimates derived from the single unit recordings. While the direction tuning of MT cells is quite wide (mean half-width at half-height approximately 50 degrees) it is shown that the cells can reliably discriminate much smaller changes in direction, and the performance of the cells with the smallest discriminanda were comparable to thresholds measured with human subjects using the same stimuli (approximately 1.1 degrees). Minimum discriminanda for individual cells occurred not at the preferred direction, that is, the peak of their tuning curves, but rather on the steep flanks of their tuning curves. This result suggests that the cells which may mediate the discrimination of motion direction may not be the cells most sensitive to that direction.
Physiological experiments have produced evidence that the middle temporal visual area (MT) of the monkey is selectively involved in the analysis of visual motion. We tested this hypothesis by studying the effects of small chemical lesions of MT on eye movements made in response to moving as opposed to stationary visual targets. We observed two deficits for eye movements made to moving targets: a monkey's ability to match the speed of his smooth pursuit eye movements to the speed of the moving target was impaired, and a monkey's ability to adjust the amplitude of a saccadic eye movement to compensate for target motion was impaired. In contrast, saccades to stationary targets were unaffected by the MT lesions, suggesting that monkeys with MT lesions had more difficulty responding to moving than to stationary stimuli. These results provide the first behavioral evidence that neural processing in MT contributes to the cortical analysis of visual motion.
Single cells were recorded in the visual cortex of monkeys trained to attend to stimuli at one location in the visual field
and ignore stimuli at another. When both locations were within the receptive field of a cell in prestriate area V4 or the
inferior temporal cortex, the response to the unattended stimulus was dramatically reduced. Cells in the striate cortex were
unaffected by attention. The filtering of irrelevant information from the receptive fields of extrastriate neurons may underlie
the ability to identify and remember the properties of a particular object out of the many that may be represented on the
retina.
We have studied the effects of voluntary attention on the induction of motion aftereffects (MAEs). While adapting, observers paid attention to one of two transparently displayed random dot patterns, moving concurrently in opposite directions. Selective attention was found to modulate the susceptibility to motion adaptation very substantially. To measure the strength of the induced MAEs we modulated the signal-to-noise ratio of a real motion signal in a random dot pattern that was used to balance the aftereffect. Results obtained for adapting to single motion vectors show that the MAE can be represented as a shift of the psychometric function for motion direction discrimination. Selective attention to the different components of transparent motion altered the susceptibility to adaptation. Shifting attention from one component to the other caused a large shift of the psychometric curves, about 70-75% of the shift measured for the separate components of the transparent adapting stimulus. We conclude that attention can differentiate between spatially superimposed motion vectors and that attention modulates the activity of motion mechanisms before or at the level where adaptation gives rise to MAEs. The results are discussed in light of the role of attention in visual perception and the physiological site for attentional modulation of MAEs.
Rhesus monkeys were trained on a conditional orientation discrimination task in order to assess whether attentive selection for a color or luminance stimulus feature would affect visual processing in extrastriate area V4. The task required monkeys to select a bar stimulus based on its color or luminance and then to discriminate the angular tilt of the selected stimulus. The majority of neurons (74%) were selectively activated when the color or luminance of the stimulus in the receptive field matched the color or luminance of the cue. The activity was attenuated when there was not a match between the stimulus and the cue. The differential activation was based on the presence or absence of the stimulus feature and was independent of spatial location. Across the population of V4 neurons, optimal stimuli that matched the selected color or luminance elicited about twice the activity as stimuli that did not match the selected feature. The feature-selective changes in activity were observed to develop beginning about 200 msec after the stimulus onset and were maintained over the remainder of the behavioral trial. In this task the activity of V4 neurons reflected a selection based on the cued feature and not simply the physical color or luminance of the receptive field stimulus. Under these conditions, the topographic representation of the neural activity in area V4 highlights the potential targets in the visual scene at the expense of background objects. These observations offer a physiological counterpart to psychophysical studies suggesting that stimuli can be preferentially selected in parallel across the visual field on the basis of a unique color or luminance feature.
1. The activity of single neurons was recorded in Macaca mulatta monkeys while they performed tasks requiring them to select a cued stimulus from an array of three to eight stimuli and report the orientation of that stimulus. Stimuli were presented in a circular array centered on the fixation target and scaled to place a single stimulus element within the receptive field of the neuron under study. The timing of the cuing event permitted the directing of visual attention to the spatial location of the correct stimulus before its presentation. 2. The effects of focal attention were examined in cortical visual areas V1, V2, and V4, where a total of 672 neurons were isolated with complete studies obtained for 94 V1, 74 V2, and 74 V4 neurons with receptive-field center eccentricities in the range 1.8-8 degrees. Under certain conditions, directed focal attention results in changes in the response of V1, V2, and V4 neurons to otherwise identical stimuli at spatially specific locations. 3. More than one-third of the neurons in each area displayed differential sensitivity when attention was directed toward versus away from the spatial location of the receptive field just before and during stimulus presentation. Both relative increases and decreases in neural activity were observed in association with attention directed at receptive-field stimuli. 4. The presence of multiple competing stimuli in the visual field was a major factor determining the presence or absence of differential sensitivity. About two-thirds of the neurons that were differentially sensitive to the attending condition in the presence of competing stimuli were not differentially sensitive when single stimuli were presented in control studies. For V1 and V2 neurons the presence of only a few (3-4) competing stimuli was sufficient for a majority of the neurons studied; a majority of the V4 neurons required six to eight stimuli in the array before significant differences between attending conditions occurred. 5. For V1 and V2 neurons the neuronal sensitivity differences between attending conditions were observed primarily at or near the peak of the orientation tuning sensitivity for each neuron; the differences were evident over a broader range of orientations in V4 neurons. 6. In conclusion, neural correlates of focal attentive processes can be observed in visual cortical processing in areas V1 and V2 as well as area V4 under conditions that require stimulus feature analysis and selective spatial processing within a field of competing stimuli.(ABSTRACT TRUNCATED AT 400 WORDS)
We often search for a face in a crowd or for a particular object in a cluttered environment. In this type of visual search, memory interacts with attention: the mediating neural mechanisms should include a stored representation of the object and a means for selecting that object from among others in the scene. Here we test whether neurons in inferior temporal cortex, an area known to be important for high-level visual processing, might provide these components. Monkeys were presented with a complex picture (the cue) to hold in memory during a delay period. The cue initiated activity that persisted through the delay among the neurons that were tuned to its features. The monkeys were then given 2-5 choice pictures and were required to make an eye movement to the one (the target) that matched the cue. About 90-120 milliseconds before the onset of the eye movement to the target, responses to non-targets were suppressed and the neuronal response was dominated by the target. The results suggest that inferior temporal cortex is involved in selecting the objects to which we attend and foveate.
Many neurons in extrastriate visual cortex have large receptive fields, and this may lead to significant computational problems whenever multiple stimuli fall within a single field. Previous studies have suggested that when multiple stimuli fall within a cell's receptive field, they compete for the cell's response in a manner that can be biased in favor of attended stimuli. In the present study we examined this role of attention in areas V1, V2, and V4 of macaque monkeys with the use of a behavioral paradigm in which attention was directed to one of two stimulus locations. When two stimuli were presented simultaneously inside the cell's receptive field (which could be accomplished only in areas V2 and V4), we found that the cell's response was strongly influenced by which of the two stimuli was attended. The size of this attention effect was reduced when the attended and ignored stimuli were presented sequentially rather than simultaneously. In addition, the effects became very weak and inconsistent in these areas when only one of the two stimuli was located inside the receptive field. Attention thus modulated sensory responses primarily when two or more simultaneous stimuli competed for access to a neuron's receptive field. As in areas V2 and V4, attention did not modulate sensory responses in area V1 when only a single stimulus was inside the receptive field. In addition, the small receptive fields in this area precluded the simultaneous presentation of attended and ignored stimuli inside the receptive field, making it impossible to determine whether attention effects would be observed under the conditions that led to consistent attention effects in areas V2 and V4. Spontaneous firing rates in areas V2 and V4 were found to be 30-40% higher when attention was directed inside rather than outside the receptive field, even when no stimulus was present in the receptive field. Spontaneous firing rates also varied according to the particular location within the receptive field that was attended. These shifts in spontaneous activity may reflect a top-down signal that biases responses in favor of stimuli at the attended location.
Functional magnetic resonance imaging was used to quantify the effects of changes in spatial and featural attention on brain activity in the middle temporal visual area and associated motion processing regions (hMT+) of normal human subjects. When subjects performed a discrimination task that directed their spatial attention to a peripherally presented annulus and their featural attention to the speed of points in the annulus, activity in hMT+ was maximal. If subjects were instead asked to discriminate the color of points in the annulus, the magnitude and volume of activation in hMT+ fell to 64 and 35%, respectively, of the previously observed maximum response. In another experiment, subjects were asked to direct their spatial attention away from the annulus toward the fixation point to detect a subtle change in luminance. The response magnitude and volume dropped to 40 and 9% of maximum. These experiments demonstrate that both spatial and featural attention modulate hMT+ and that their effects can work in concert to modulate cortical activity. The high degree of modulation by attention suggests that an understanding of the stimulus-driven properties of visual cortex needs to be complemented with an investigation of the effects of task-related factors on visual processing.
Many attempts to predict the biotic responses to climate change rely on the 'climate envelope' approach, in which the current distribution of a species is mapped in climate-space and then, if the position of that climate-space changes, the distribution of the species is predicted to shift accordingly. The flaw in this approach is that distributions of species also reflect the influence of interactions with other species, so predictions based on climate envelopes may be very misleading if the interactions between species are altered by climate change. An additional problem is that current distributions may be the result of sources and sinks, in which species appear to thrive in places where they really persist only because individuals disperse into them from elsewhere. Here we use microcosm experiments on simple but realistic assemblages to show how misleading the climate envelope approach can be. We show that dispersal and interactions, which are important elements of population dynamics, must be included in predictions of biotic responses to climate change.
We examined how attention affected the orientation tuning of 262 isolated neurons in extrastriate area V4 and 135 neurons in area V1 of two rhesus monkeys. The animals were trained to perform a delayed match-to-sample task in which oriented stimuli were presented in the receptive field of the neuron being recorded. On some trials the animals were instructed to pay attention to those stimuli, and on other trials they were instructed to pay attention to other stimuli outside the receptive field. In this way, orientation-tuning curves could be constructed from neuronal responses collected in two behavioral states: one in which those stimuli were attended by the animal and one in which those stimuli were ignored by the animal. We fit Gaussians to the neuronal responses to twelve different orientations for each behavioral state. Although attention enhanced the responses of V4 neurons (median 26% increase) and V1 neurons (median 8% increase), selectivity, as measured by the width of its orientation-tuning curve, was not systematically altered by attention. The effects of attention were consistent with a multiplicative scaling of the driven response to all orientations. We also found that attention did not cause systematic changes in the undriven activity of the neurons.
It is well established that attention modulates visual processing in extrastriate cortex. However, the underlying neural mechanisms are unknown. A consistent observation is that attention has its greatest impact on neuronal responses when multiple stimuli appear together within a cell's receptive field. One way to explain this is to assume that multiple stimuli activate competing populations of neurons and that attention biases this competition in favor of the attended stimulus. In the absence of competing stimuli, there is no competition to be resolved. Accordingly, attention has a more limited effect on the neuronal response to a single stimulus. To test this interpretation, we measured the responses of neurons in macaque areas V2 and V4 using a behavioral paradigm that allowed us to isolate automatic sensory processing mechanisms from attentional effects. First, we measured each cell's response to a single stimulus presented alone inside the receptive field or paired with a second receptive field stimulus, while the monkey attended to a location outside the receptive field. Adding the second stimulus typically caused the neuron's response to move toward the response that was elicited by the second stimulus alone. Then, we directed the monkey's attention to one element of the pair. This drove the neuron's response toward the response elicited when the attended stimulus appeared alone. These findings are consistent with the idea that attention biases competitive interactions among neurons, causing them to respond primarily to the attended stimulus. A quantitative neural model of attention is proposed to account for these results.
We previously proposed a quantitative model of early visual processing in primates, based on non-linearly interacting visual filters and statistically efficient decision. We now use this model to interpret the observed modulation of a range of human psychophysical thresholds with and without focal visual attention. Our model - calibrated by an automatic fitting procedure - simultaneously reproduces
thresholds for four classical pattern discrimination tasks,
performed while attention was engaged by another concurrent task. Our model then predicts that the seemingly complex improvements of certain thresholds, which we observed when attention was fully available for the discrimination tasks, can best be explained by a strengthening of competition among early visual filters.
Data from a national butterfly monitoring scheme were analysed to test for relationships between temperature and three phenological measures, duration of flight period and timing of both first and peak appearance. First appearances of most British butterflies has advanced in the last two decades and is strongly related to earlier peak appearance and, for multibrooded species, longer flight period. Mean dates of first and peak appearance are examined in relation to Manley's central England temperatures, using regression techniques. We predict that, in the absence of confounding factors, such as interactions with other organisms and land-use change, climate warming of the order of 1 °C could advance first and peak appearance of most butterflies by 2–10 days.
Summary: Immigration and spread of lepidotera in Finland during the period 1869-1960. - Selostus ; Perhosen immigraatio ja ekspansio Suomessa vuosina 1869-1960. Diss. -- Helsingin yliopisto.
Physiological experiments indicate that the middle temporal visual area (MT) of primates plays a prominent role in the cortical analysis of visual motion. We investigated the role of MT in visual perception by examining the effect of chemical lesions of MT on psychophysical thresholds. We trained rhesus monkeys on psychophysical tasks that enabled us to assess their sensitivity to motion and to contrast. For motion psychophysics, we employed a dynamic random dot display that permitted us to vary the intensity of a motion signal in the midst of masking motion noise. We measured the threshold intensity for which the monkey could successfully complete a direction discrimination. In the contrast task, we measured the threshold contrast for which the monkeys could successfully discriminate the orientation of stationary gratings. Injections of ibotenic acid into MT caused striking elevations in motion thresholds, but had little or no effect on contrast thresholds. The results indicate that neural activity in MT contributes selectively to the perception of motion.
The visual system is constantly inundated with information received by the eyes, only a fraction of which seems to reach visual awareness. This selection process is one of the functions ascribed to visual attention. Although many studies have investigated the role of attention in shaping neuronal representations in the visual cortex, few have focused on attentional modulation of neuronal signals related to visual motion. Here we report that the responses of direction-selective neurons in monkey visual cortex are greatly influenced by attention, and that this modulation occurs as early in the cortical hierarchy as the level of the middle temporal visual area (MT). Our finding demonstrates a stronger and earlier influence of attention on motion processing along the dorsal visual pathway than previously recognized.
We have previously documented the exquisite motion sensitivity of neurons in extrastriate area MT by studying the relationship between their responses and the direction and strength of visual motion signals delivered to their receptive fields. These results suggested that MT neurons might provide the signals supporting behavioral choice in visual discrimination tasks. To approach this question from another direction, we have now studied the relationship between the discharge of MT neurons and behavioral choice, independently of the effects of visual stimulation. We found that trial-to-trial variability in neuronal signals was correlated with the choices the monkey made. Therefore, when a directionally selective neuron in area MT fires more vigorously, the monkey is more likely to make a decision in favor of the preferred direction of the cell. The magnitude of the relationship was modest, on average, but was highly significant across a sample of 299 cells from four monkeys. The relationship was present for all stimuli (including those without a net motion signal), and for all but the weakest responses. The relationship was reduced or eliminated when the demands of the task were changed so that the directional signal carried by the cell was less informative. The relationship was evident within 50 ms of response onset, and persisted throughout the stimulus presentation. On average, neurons that were more sensitive to weak motion signals had a stronger relationship to behavior than those that were less sensitive. These observations are consistent with the idea that neuronal signals in MT are used by the monkey to determine the direction of stimulus motion. The modest relationship between behavioral choice and the discharge of any one neuron, and the prevalence of the relationship across the population, make it likely that signals from many neurons are pooled to form the data on which behavioral choices are based.
A series of experiments investigated concurrent discriminations of surface and nonsurface attributes, including color, brightness, texture, length, location, and motion. In all cases but one, results matched those previously reported: Interference occurred when two discriminations concerned different objects, but not when they concerned the same one. In the two-object case, interference was the same whether discriminations were similar (e.g., two surface discriminations) or different (e.g., one surface, one boundary). Such results support a model of visual attention in which separate visual subsystems are coordinated, converging to work on surface and boundary properties of the same selected object. A partial exception is color: For reasons that are unclear, color escapes two-object interference except from other, concurrent surface discriminations.
How does voluntary attention to one attribute of a visual stimulus affect the neural processing of that stimulus? We used functional magnetic resonance imaging to examine the attentional modulation of neural activity in the human homolog of the MT-MST complex, which is known to be involved in the processing of visual motion. Using a visual stimulus containing both moving and stationary dots, we found significantly more MT-MST activation when subjects attended to the moving dots than when they attended to the stationary dots, even though the visual stimulus was identical during the two conditions.
Attention and contrast have similar effects on competitive interactions in macaque area V4
- J H Reynolds
- R Desimone
Reynolds, J. H. & Desimone, R. Attention and contrast have similar effects on competitive interactions
in macaque area V4. Soc. Neurosci. Abstr. 23, 302 (1997).
Attentional modulation of direction-selective responses in MT/MST resembles the effect of reducing contrast of unattended stimuli
- S Treue
- J C Martinez
Treue, S. & Martinez, J. C. Attentional modulation of direction-selective responses in MT/MST
resembles the effect of reducing contrast of unattended stimuli. Soc. Neurosci. Abstr. 24, 1249 (1998).
Attention enhances neuronal responses without altering orientation selectivity in macaque area V4
- C J Mcadams
- J H Maunsell
McAdams, C. J. & Maunsell, J. H. R. Attention enhances neuronal responses without altering
orientation selectivity in macaque area V4. Neurosci. Abstr. 22, 1197 (1996).
Attention does not sharpen direction-tuning curves in macaque monkey MT/ MST neurons
- J Martinez
- S Treue
Martinez, J. & Treue, S. Attention does not sharpen direction-tuning curves in macaque monkey MT/
MST neurons. Soc. Neurosci. Abstr. 24, 649 (1998).
Climate-related long-term faunal changes in a California rocky intertidal community
- J P Barry
- C H K Baxtern
- R D Sagarin
- S E Gilman
Barry, J. P., Baxtern, C. H. K., Sagarin, R. D. & Gilman, S. E. Climate-related long-term faunal changes
in a California rocky intertidal community. Science 267, 672-675 (1995).
Agriculture and habitat loss in Europe
- D Baldock
Baldock, D. Agriculture and habitat loss in Europe (CAP Discussion paper No 3, Gland, Switzerland,
1990).
Systematic and faunistic studies on butterflies
- P R Ackery
Ackery, P. R. Systematic and faunistic studies on butterflies. In Biology of Butterflies (eds Vane-Wright,
R. I. & Ackery, P. R.) 9-21 (Academic, London, 1984).
- T Tolman
Tolman, T. Butterflies of Britain and Europe (HarperCollins, London, 1997).