The Influence of Landscape Grain Size on Butterfly Diversity in Grasslands

The relationship between butterfly diversity and both habitat and landscape variables was studied in two areas of southern Sweden. The habitat quality of the grasslands was similar in the two study areas but the landscape pattern differed in grain size and amount of grassland and forest. Using a transect survey method, a total of 3341 butterflies were observed and 30 taxa identified. We found that both habitat and landscape variables influenced the butterfly diversity of the investigated grasslands. Species composition differed markedly between the two study areas. A study area with a fine-grained landscape pattern, a high cover of semi-natural grassland and many forest edges had twice as many butterfly species but half the number of individuals compared with a coarser-grained study area with larger grasslands widely spread in a matrix of arable fields. The results of our study indicate that both habitat quality and landscape pattern have to be considered when developing conservation strategies for grassland butterflies.     

Species richness, composition and abundance of fruit-feeding butterflies in the Brazilian Atlantic Forest: comparison between a fragmented and a continuous landscape

Aim  To evaluate frugivorous butterflies as indicators of forest disturbance in the Brazilian Atlantic Forest.
Location  The study area is located in the municipality of Cotia, São Paulo State, south-eastern Brazil (23°35'−23°50' S, 46°45'−47°15' W).
Methods  Sampling was done at four sites inside a large forest block, the Morro Grande State Reserve, and in five forest fragments in an adjacent fragmented landscape. Butterflies were sampled with portable traps, baited with a fermented mixture of banana and sugar cane juice. Sampling was carried out during the period most favourable for the capture of frugivorous butterflies in south-eastern Brazil.
Results  All richness-related results indicated no effect of forest fragmentation on the frugivorous butterfly guild, concurring with the suggestion of appreciable resistance of Atlantic Forest butterflies to habitat modification. However, species composition discriminated between the two landscapes, indicating that fragmentation may have effects beyond simple species richness. When species were analysed individually, clear patterns of distribution emerged, with some species that were very abundant in the fragmented landscape being practically absent in the continuous landscape, and vice versa. This pattern seems consistent even for some subfamilies.
Main conclusion  Our findings support the usefulness of the frugivorous butterfly guild as a biological indicator of forest disturbance effects in one of the world's most threatened ecosystems.     

Functional composition and phenology of fruit-feeding butterflies in a fragmented landscape: variation of seasonality between habitat specialists

For butterflies, tolerance to the matrix may be an important criterion of habitat occurrence in fragmented landscapes. Here we examine the relative effects of habitat fragmentation and the surrounding agricultural matrix on the functional composition of fruit-feeding butterflies of the Atlantic rain forest in southeastern Brazil. Generalized linear models were used to detect the effects of landscape metrics on butterfly richness and abundance of the total assemblage and functional groups. Circular statistics were used to analyze the patterns of monthly abundance of the total assemblage and functional groups in the forest remnants and the surrounding matrices. In total, 650 butterflies representing 57 species were captured; species composition differed significantly between the forest fragments and the surrounding matrices. We recorded 22 forest specialists, 18 matrix specialists, 11 common species with matrix preference and six common species with forest preference. Forest connectivity favored the richness of forest specialists, while habitat fragmentation enhances the richness and abundance of matrix-tolerant species. Circular analysis revealed that forest specialists were more abundant in the rainy season while matrix-tolerant species proliferated in the dry season. Although maintaining connectivity of forest fragments may increase the mobility and dispersion of forest species, our results showed that landscape fragmentation modify butterfly assemblage by promoting an increase of matrix tolerant species with detriment of forest specialists.     

Temporal abundance patterns of butterfly communities (Lepidoptera: Nymphalidae) in the Ecuadorian Amazonia and their relationship with climate

Tropical insects show temporal changes in their abundance and climate is one of the most influential factors. For tropical butterflies, few studies have quantified this relationship or analyzed changes in community composition and structure throughout time. Communities of butterflies attracted to rotting-carrion bait in one area of the Yasuni National Park, in Ecuadorian Amazonia were examined for these relationships. Butterfly communities in three different strata of the forest were sampled over 13 months using traps with rotten shrimp bait. In total, 9236 individuals of 208 species were collected between April 2002 and April 2003. The composition and structure of butterfly communities showed significant variation during the survey with a constant replacement of species throughout the year. Additionally, these communities had the highest species richness and abundance during the months with high temperatures and intermediate precipitation. Despite relatively low variation, temperature was the most significant climatic factor explaining differences in butterfly richness and abundance throughout the year. This significant response of butterfly communities to slight temperature variations reinforce the need of temporal studies to better predict how tropical butterfly populations will respond to predicted climate change.     

Butterfly Community Composition Across a Successional Gradient in a Human‐disturbed Afro‐tropical Rain Forest

Knowledge of the recovery of insect communities after forest disturbance in tropical Africa is very limited. Here, fruit‐feeding butterflies in a tropical rain forest at Kibale National Park, Uganda, were used as a model system to uncover how, and how fast, insect communities recover after forest disturbance. We trapped butterflies monthly along a successional gradient for one year. Traps were placed in intact primary forest compartments, heavily logged forest compartments with and without arboricide treatment approximately 43 years ago, and in conifer‐clearcut compartments, ranging from 9 to 19 years of age. The species richness, total abundance, diversity, dominance, and similarity of the community composition of butterflies in the eight compartments were compared with uni‐ and multivariate statistics. A total of 16,728 individuals representing 88 species were trapped during the study. Butterfly species richness, abundance, and diversity did not show an increasing trend along the successional gradient but species richness and abundance peaked at intermediate stages. There was monthly variation in species richness, abundance, diversity and composition. Butterfly community structure differed significantly among the eight successional stages and only a marginal directional change along the successional gradient emerged. The greatest number of indicator species and intact forest interior specialists were found in one of the primary forests. Our results show that forest disturbance has a long‐term impact on the recovery of butterfly species composition, emphasizing the value of intact primary forests for butterfly conservation.     

The differences of butterfly (Lepidoptera, Papilionoidea) communities in habitats with various degrees of disturbance and altitudes in tropical forests of Vietnam

A survey was conducted on the species composition, richness and abundance of Papilionoidea (excluding Lycaenidae) butterfly fauna in habitats with various degrees of disturbance and altitudes in tropical forests at Tam Dao National Park, northern Vietnam in 2001. The transect method was used to collect data in the survey. Six transects representing different habitat types at two sites, one site located at a low elevation of 200–250 m a.s.l., and the other located at a high elevation of 950–1000 m a.s.l., were chosen: three transects for each site, with a length of 500 m for each transect. A total of 3594 individuals of 127 species in 240 sets of data were recorded from various habitats. The differences in butterfly composition, species richness, abundance and diversity in different habitat types and altitudes were analyzed. The results showed significant differences of butterfly diversity among the different habitat types and between the low and high altitude sites. The butterfly diversity, species richness and species abundance in the low elevation habitats were higher than in the high elevation habitats. The highest diversity of butterflies occurred in the mixed habitats of agriculture, scrub and clearing lands of high disturbance. However, butterflies most important for conservation are associated with undisturbed or moderately disturbed forests only.     

Importance of semi-natural habitats for the conservation of butterfly communities in landscapes dominated by pine plantations

While the area of plantation forests continues to increase worldwide, their contribution to the conservation of biodiversity is still controversial. There is a particular concern on the central role played by natural habitat remnants embedded within the plantation matrix in conserving species-rich insect communities. We surveyed butterflies in maritime pine plantation landscapes in south-western France in 83 plots belonging to seven habitat types (five successional stages of pine stands, native deciduous woodlands and herbaceous firebreaks). The effect of plot, habitat and landscape attributes on butterfly species richness, community composition and individual species were analysed with a General Linear Model (GLM), partial Canonical Correspondence Analysis (CCA) and the IndVal method. The most important factors determining butterfly diversity and community composition were the presence of semi-natural habitats (deciduous woodlands and firebreaks) at the landscape scale and the composition of understorey vegetation at the plot scale. Pure effects of plot variables explained the largest part of community variation (12.8%), but landscape factors explained an additional, independent part (6.7%). Firebreaks were characterized by a higher species richness and both firebreaks and deciduous woodlands harboured species not or rarely found in pine stands. Despite the forest-dominated landscape, typical forest butterflies were rare and mainly found in the deciduous woodlands. Threatened species, such as Coenonympha oedippus and Euphydryas aurinia, were found in pine stands and in firebreaks, but were more abundant in the latter. In the studied plantation forest, the conservation of butterflies depends mainly on the preservation of semi-natural habitats, an adequate understorey management and the maintenance of soil moisture levels.     

Higher mobility of butterflies than moths connected to habitat suitability and body size in a release experiment

Mobility is a key factor determining lepidopteran species responses to environmental change. However, direct multispecies comparisons of mobility are rare and empirical comparisons between butterflies and moths have not been previously conducted. Here, we compared mobility between butterflies and diurnal moths and studied species traits affecting butterfly mobility. We experimentally marked and released 2011 butterfly and 2367 moth individuals belonging to 32 and 28 species, respectively, in a 25 m × 25 m release area within an 11‐ha, 8‐year‐old set‐aside field. Distance moved and emigration rate from the release habitat were recorded by species. The release experiment produced directly comparable mobility data in 18 butterfly and 9 moth species with almost 500 individuals recaptured. Butterflies were found more mobile than geometroid moths in terms of both distance moved (mean 315 m vs. 63 m, respectively) and emigration rate (mean 54% vs. 17%, respectively). Release habitat suitability had a strong effect on emigration rate and distance moved, because butterflies tended to leave the set‐aside, if it was not suitable for breeding. In addition, emigration rate and distance moved increased significantly with increasing body size. When phylogenetic relatedness among species was included in the analyses, the significant effect of body size disappeared, but habitat suitability remained significant for distance moved. The higher mobility of butterflies than geometroid moths can largely be explained by morphological differences, as butterflies are more robust fliers. The important role of release habitat suitability in butterfly mobility was expected, but seems not to have been empirically documented before. The observed positive correlation between butterfly size and mobility is in agreement with our previous findings on butterfly colonization speed in a long‐term set‐aside experiment and recent meta‐analyses on butterfly mobility.     

宁夏贺兰山自然保护区蝴蝶群落多样性及其环境影响因子

宁夏贺兰山自然保护区蝴蝶群落多样性及其与环境因素的关系,2017年5-9月采用样线法对贺兰山东麓6类生境和不同干扰类型10条样线的蝴蝶群落结构及其多样性季节动态进行调查。共记录蝴蝶5科36属45种,蛱蝶科Nymphalidae的属和物种数最多,为17属19种;凤蝶科Papilionidae最少,仅1属1种。菜粉蝶Pieris rapae、云粉蝶Pontia daplidice、斑缘豆粉蝶Colias erate和小檗绢粉蝶Aporia hippia是该地区的优势种,个体数量分别占总个体数的11.76%、11.63%、11.21%和10.17%。不同生境样线优势类群和常见类群不同。蝴蝶的栖息地偏好与寄主植物有关,蝴蝶的生境分布类型可分为生境广布型、湿润平原型、荒漠半荒漠草原型和山地森林型。蝴蝶群落Shannon-Wiener多样性和丰富度指数以灰榆疏林草地生境最高,优势度最低。各物种在生境内的季节变化趋势与不同生境植被生长季节相关,高峰期为7-8月。不同调查时间蝴蝶的优势种和常见种不同。物种数以7月份调查最多,有33种,占全年调查总物种数的73.33%;5月份调查最少,有20种。蝴蝶群落Shannon-Wiener多样性和丰富度指数以8月份最大,5月份最小。蝴蝶成虫发生类型分为全年发生型、春季型、夏季型和夏秋季型。不同生境和季节发生的优势种可以作为对生境状况进行评估的指示类群。采用CCA分析物种分布与微环境因子的关系,海拔对蝴蝶物种多样性分布格局有显著影响。蝴蝶丰富度与海拔、温度、风速显著正相关。适度干扰有利于蝶类多样性增加,较强的人为干扰会影响蝶类栖息环境,降低蝶类多样性。因此,生境差异性和干扰与蝴蝶群落的物种多样性密切相关,维持贺兰山垂直植被带的生境异质性和保持适度干扰是保护蝴蝶多样性的关键。     

Importance of boreal grasslands in Sweden for butterfly diversity and effects of local and landscape habitat factors

A widespread decline in biodiversity in agro-ecosystems has been reported for several groups of organisms in Western Europe. The butterfly fauna was studied in 60 selected semi-natural grasslands in a coniferous-dominated boreal landscape in south-eastern Sweden. The aim was to investigate how butterfly assemblages were affected by the amount of semi-natural grasslands in the surrounding landscape. Furthermore, we wanted to determine if semi-natural grasslands in boreal landscapes harboured species otherwise declining in other parts of Europe. For each study site, the amounts of semi-natural grasslands in the landscape within radii of 500, 2,000 and 5,000 m were studied. Nine local habitat factors were also recorded. Only the amount of semi-natural grasslands within a 5,000 m radius could explain a significant part of the variation in butterfly composition, but there was no clear relationship between the amount of semi-natural grassland and butterfly diversity. Instead, this study showed that local habitat quality was very important for butterfly diversity at individual sites. Flower abundance, sward height and herb composition were the most important local factors. Patches surrounded by a small amount of semi-natural grasslands had high butterfly diversity, contrary to expectations. This may be explained by the fact that forest habitat provides a matrix with several features suitable for butterflies. The butterfly fauna was rich in species representative of low-productivity grasslands, species that are declining in other countries in Western Europe.     

From Forest to Ffarmland: Butterfly Diversity and Habitat Associations Along a Gradient of Forest Conversion in Southwestern Cameroon

Worldwide, tropical landscapes are increasingly dominated by human land use systems and natural forest cover is decreasing rapidly. We studied frugivorous butterflies and several vegetation parameters in 24 sampling stations distributed over near-primary forest (NF), secondary forest (SF), agroforestry and annual culture sites in the Northeastern part of the Korup region, SW Cameroon. As in other studies, both butterfly species richness and abundance were significantly affected by habitat modification. Butterfly richness and abundance were highest in SF and agroforestry sites and significantly lower in NF and annual crop sites. Butterfly species richness increased significantly with increasing tree density, but seemed to decrease with increasing herb diversity and density in annual crop farms. A significant negative correlation was found between butterfly geographic range and their preference for NF sites. Our results also showed that agroforestry systems, containing remnants of natural forest, can help to sustain high site richness, but appear to have low complementarity through loss of endemic species confined to more undisturbed habitats. Our study also indicated that the abundance of selected restricted-range butterflies, particularly in the family Nymphalidae, appears to be a good indicator to assess and monitor forest disturbance.     

西双版纳热带植物园蝴蝶的多样性及变化

中国科学院西双版纳热带植物园（简称“版纳植物园”）保存着上万种植物,且生境多样,具有较高的蝴蝶多样性。本研究选择三类代表性生境：片段化雨林、次生林和专类园,聚焦于环境指示物种蝴蝶这一类群,通过样线法系统调查一年内蝴蝶多样性及其变化。观测结果显示：蝴蝶在版纳植物园内全年发生,共调查到其成虫5科126属218种6 015头,其中蛱蝶科多样性最高。蝴蝶种类及数量随月动态变化,生境间有差异,7-8月种类和数量达到最高峰;1月种类最少,而5-6月数量最低;每月均出现的种类仅有12种,绝大部分种类分散发生于不同月份。影响蝴蝶群落多样性的气候因子中,月最高温显著影响蝴蝶群落的物种丰富度和数量,月最低温显著影响物种丰富度、香农多样性和辛普森多样性,月平均温仅显著影响香农多样性。在版纳的三个典型季节中蝴蝶多样性存在差异,雨季物种丰富度最高,干热季香农和辛普森指数最高;雨季和雾凉季蝴蝶群落组成差异大,仅雾凉季与干热季的蝴蝶群落呈现中等程度相似。此外,在片段化雨林、次生林和专类园这3种不同生境中,蝴蝶群落组成也存在差异,蝴蝶物种丰富度和香农指数在次生林中最高,而辛普森指数则是片段化雨林最高;仅次生林与片段化雨林的蝴蝶群落呈现出中等程度相似。本研究揭示了版纳植物园蝴蝶群落的种类组成与月动态变化规律,并明确了不同季节和生境中蝴蝶群落的多样性变化,可为区域蝴蝶多样性观测及保护提供参考依据。     

Ecological indicators of habitat and biodiversity in a Neotropical landscape: multitaxonomic perspective

Ecological indicators of habitat and biodiversity in a Neotropical landscape: multitaxonomic perspective. The use of indicator species to characterize specific ecological areas is of high importance in conservation/restoration biology. The objective of this study was to identify indicator species of diverse taxa that characterize different landscape units, and to better understand how management alters species composition. We identified two ecomosaics, tropical rain forest and the agricultural matrix, each one comprised of four landscape units. The taxonomic groups studied included birds (highly mobile), butterflies (moderately mobile), terrestrial gastropods (less mobile) and trees (sessile). Sampling efficiency for both ecomosaics was > or = 86%. We found 50 mollusks, 74 butterflies, 218 birds and 172 tree species, for a total of 514 species. Using ordination and cluster analysis, we distinguished three habitat types in the landscape: tropical rainforest, secondary vegetation and pastures with scattered trees and live fences. The InVal (> or = 50%) method identified 107 indicator species, including 45 tree species, 38 birds, 14 butterflies and 10 gastropods. Of these, 35 trees, 10 birds, four butterflies and eight gastropods were forest indicators. Additionally, 10, 28, 10 and two species, respectively per group, were characteristic of the agricultural matrix. Our results revealed a pattern of diversity decrease of indicator species along the rainforest-secondary forest-pasture gradient. In the forest, the gastropods Carychium exiguum, Coelocentrum turris, Glyphyalinia aff. indentata y Helicina oweniana were significantly correlated (p < 0.05) with 90% of the other groups of flora and fauna indicator species. These findings suggest that gastropods may be good indicators of forest habitat quality and biodiversity. The secondary vegetation is an intermediate disturbance phase that fosters high diversity in the agricultural matrix. We exemplify a multitaxa approach, including mesofauna, for ecological monitoring of agricultural landscapes.     

云南高黎贡山地区蝴蝶群落多样性

位于滇西北的高黎贡山是全球生物多样性研究和保护的热点地区之一, 然而该地区昆虫多样性缺乏系统调查和总结。本研究聚焦蝴蝶类群, 考虑该区域高山峡谷特点, 结合海拔梯度、生境类型和季节变化, 采用样线法调查、分析蝴蝶物种多样性及群落结构变化。结果显示: 共观测记录到蝴蝶2,055只, 隶属于5科85属151种, 在历史记录上新增27种, 使该地区已知蝴蝶种类达488种; 其中蛱蝶科物种多样性最高, 灰蝶科次之, 凤蝶科最低。蝴蝶群落多样性分析结果表明: 中海拔1,000-2,000 m区域种类丰富、多样性指数最高; 低海拔区蝴蝶分布明显聚集, 并且与高海拔地区空间上分离, 少有重叠。该地区不同生境中蝴蝶的种类及数量差异也较大, 物种数及多样性指数在自然保护区最高、边缘交错带居中及农业种植区最低。此外, 蝴蝶的种类和数量也存在季节差异, 春季调查到的个体数少, 夏季观察到的物种数少, 两年秋季调查到的物种丰富度、多样性均高, 但存在季节内变化。总之, 高黎贡山地区不同海拔、生境、季节间和季节内蝴蝶群落组成有自身特点, 共存物种有限, 蝴蝶群落相似性低。综合评估分布于该地区的蝴蝶保护种类, 包括易危种17种、近危种50种, 有国家二级保护蝴蝶3种。本研究弄清了高黎贡山地区蝴蝶的物种本底, 并调查获得其多样性随海拔、生境和季节变化的模式, 为加强区域物种多样性监测、保护生物多样性提供了科学依据。     

Demography and mobility of three common understory butterfly species from tropical rain forest of Papua New Guinea

The mobility of butterflies determines their ability to find host plant species, and thus their potential host plant range, as well as their ability to maintain meta-populations in fragmented habitats. While butterfly movement has been extensively studied for temperate species, very little is known for tropical forest species. A mark-release-recapture study of the three most common butterfly species in the understory of a lowland primary rainforest in Papua New Guinea included 3,705, 394 and 317 marked individuals of Danis danis, Taenaris sp. and Parthenos aspila respectively, with 1,031, 78 and 40 butterfly individuals recaptured at least once. Over a period of 6 weeks there were almost 22,000 individuals belonging to these three species hatching within or entering our four study plots totaling 14.58 ha in area. The most abundant species, D. danis, with 20,000 individuals, showed highly variable population densities during the study. The residency time in the studied plots was highest for P. aspila (84 days), as individual butterflies stayed mostly in a single gap; we estimated that less than 1 % of individuals disperse 1 km or more. Similar movement probability was found in D. danis whilst in Taenaris sp., 10 % of the population disperses ≥1 km. Movement distances of D. danis were more than sufficient to locate its host plant, Derris elliptica, which occurred in 61 % of the 20 × 20 m subplots within a 50 ha plot. Compared with temperate species, our three species have much longer life spans, but their movement patterns remain within the known mobility estimates of temperate species. The mobility of D. danis is close to the average for temperate Lycaenidae, while Taenaris sp. is more mobile and P. aspila less mobile than the mean for all temperate species.     

Dispersal of butterflies in a New Guinea rainforest: using mark–recapture methods in a large,homogeneous habitat

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Butterfly species diversity and their floral preferences in the Rupa Wetland of Nepal

Floral attributes often influence the foraging choices of nectar‐feeding butterflies, given the close association between plants and these butterfly pollinators. The diversity of butterflies is known to a large extent in Nepal, but little information is available on the feeding habits of butterflies. This study was conducted along the periphery of Rupa Wetland from January to December 2019 to assess butterfly species diversity and to identify the factors influencing their foraging choices. In total, we recorded 1535 individuals of 138 species representing all six families. For our examination of butterfly–nectar plant interactions, we recorded a total of 298 individuals belonging to 31 species of butterfly visiting a total of 28 nectar plant species. Overall, total butterfly visitation was found to be significantly influenced by plant category (herbaceous preferred over woody), floral color (yellow white and purple preferred over pink), and corolla type (tubular preferred over nontubular). Moreover, there was a significant positive correlation between the proboscis length of butterflies and the corolla tube length of flowers. Examining each butterfly family separately revealed that, for four of the families (Lycaenidae, Nymphalidae, Papilionidae, and Pieridae), none of the tested factors (flower color, plant category, and corolla type) were shown to significantly influence butterfly abundance at flowers. However, Hesperidae abundance was found to be significantly influenced by both flower color (with more butterflies observed at yellow flowers than purple) and flower type (with more butterflies observed at tubular flowers than nontubular flowers). Our results reveal that Rupa Lake is a suitable habitat for butterflies, providing valuable floral resources. Hence, further detailed studies encompassing all seasons, a greater variety of plants, and other influential factors in different ecological regions are fundamental for creating favorable environments to sustain important butterfly pollinators and help create balanced wetland ecosystems.     

The Contribution of Tropical Secondary Forest Fragments to the Conservation of Fruit-feeding Butterflies: Effects of Isolation and Age

Concomitant with the rapid loss of tropical mature forests, the relative abundance of secondary forests is increasing steadily and the latter are therefore of growing interest for conservation. We analysed species richness of fruit-feeding nymphalid butterflies in secondary forest fragments of different age and isolation and in mature forest at the eastern margin of the Lore Lindu National Park in Central Sulawesi, Indonesia. From April to August 2001 we collected 2322 individuals of fruit-feeding butterflies, belonging to 33 species. Butterfly species richness increased with succession, but was significantly higher in mature forests than in all types of secondary forest. Isolation of the forest fragments did not have a significant effect on butterfly species richness in the range of distances (up to 1700 m) studied. Rather it appeared to affect only a few species. Species richness of endemic species was higher than of non-endemic species. Although endemic species were most diverse in mature forests, many species captured were restricted to secondary forests. Our results show that mature forest is essential for the conservation of nymphalid butterflies and for the endemic species in this area. However, considering the relatively large number of species found in these rather small habitat islands, secondary forest fragments, especially older successional stages, can be taken into account in conservation efforts and thus contribute to the preservation of tropical biodiversity on a landscape scale.     

Species traits help explain butterfly habitat use in a tropical forest

1. When species can access all parts of the landscape, species-sorting metacommunity theory predicts that community composition depends on habitat choice and interactions with other species and the environment. These filtering processes can also depend on species' traits.
2. The authors investigated how traits mediate a species-sorting process in determining butterfly community composition in a naturally patchy landscape in the tropical Western Ghats, India. The authors asked, do traits mediate access to certain habitats and does seasonality affect these patterns? The authors surveyed 56 habitat patches in three habitat types: laterite plateau grasslands, ridge grassland, and moist-deciduous forest, in a 65-km² landscape.
3. Non-palatable butterflies showed similar occurrences across seasons and habitats, but palatable butterflies were less commonly encountered in open habitats in the dry season. Polyphagous butterflies occurred infrequently in the dry season in laterite habitats, potentially indicating emigration or diapause patterns are linked to diet breadth.
4. All species were present in all habitats, implying dispersal does not limit access to different habitat patches, consistent with the species-sorting metacommunity concept. Nevertheless, butterfly occurrence was strongly influenced by the interaction of mobility and habitat type with sedentary species occurring less often in low-resource open laterite patches than mobile species.
5. Species sorting is typically regarded as occurring directly through environmental filters, but here the authors suggest that the environmental filter acts through movement limitations. Studies integrating landscape heterogeneity and species characteristics will help us better understand metacommunities and species distributions in nature.

     

Do asynchronies in extinction debt affect the structure of trophic networks? A case study of antagonistic butterfly larvae–plant networks

Habitat loss and fragmentation affect species richness in fragmented habitats and can lead to immediate or time‐delayed species extinctions. Asynchronies in extinction and extinction debt between interacting species may have severe effects on ecological networks. However, these effects remain largely unknown. We evaluated the effects of habitat patch and landscape changes on antagonistic butterfly larvae–plant trophic networks in Mediterranean grasslands in which previous studies had shown the existence of extinction debt in plants but not in butterflies. We sampled current species richness of habitat‐specialist and generalist butterflies and vascular plants in 26 grasslands. We assessed the direct effects of historical and current patch and landscape characteristics on species richness and on butterfly larvae–plant trophic network metrics and robustness. Although positive species‐ and interactions–area relationships were found in all networks, structure and robustness was only affected by patch and landscape changes in networks involving the subset of butterfly specialists. Larger patches had more species (butterflies and host plants) and interactions but also more compartments, which decreased network connectance but increased network stability. Moreover, most likely due to the rescue effect, patch connectivity increased host‐plant species (but not butterfly) richness and total links, and network robustness in specialist networks. On the other hand, patch area loss decreased robustness in specialist butterfly larvae–plant networks and made them more prone to collapse against host plant extinctions. Finally, in all butterfly larvae–plant networks we also detected a past patch and landscape effect on network asymmetry, which indicates that there were different extinction rates and extinction debts for butterflies and host plants. We conclude that asynchronies in extinction and extinction debt in butterfly–plant networks provoked by patch and landscape changes caused changes in species richness and network links in all networks, as well as changes in network structure and robustness in specialist networks.