Forest Beetle Research Articles

Diversity and prevalence of entomopathogenic fungi (Ascomycota, Hypocreales) in epidemic populations of bark beetles (Coleoptera, Scolytinae) in spruce forests of the Tatra National Park in Slovakia

Bark beetles are serious forest pests in Slovakia. Their outbreaks may have significant ecological and economic impacts on spruce forests. There is a variety of natural enemies that activate themselves during population outbreaks of insects and entomopathogenic fungi belong to important antagonists with a potential to regulate populations of their hosts. In 2014–2016, species richness and prevalence of entomopathogenic fungi were evaluated during the bark beetle outbreaks in spruce forests affected by windstorms in the Tatra National Park in Slovakia. Three Beauveria species, B. bassiana, B. caledonica and B. pseudobassiana, with Metapochonia bulbillosa were identified from 271 specimens of three bark beetle species, Ips typographus, Ips amitinus and Pityogenes chalcographus. Beauveria bassiana was the dominant pathogen and infected all three bark beetle species. Phylogenetic analysis identified three phylogenetic groups of B. bassiana in the evaluated host populations. M. bulbillosa was reported for the first time from bark beetle hosts and Slovakia. The prevalence of fungal infection in natural populations of I. typographus was low, varied between 0.07 and 0.72%, and have little influence on the bark beetle abundance.

Diversity and prevalence of entomopathogenic fungi (Ascomycota, Hypocreales) in epidemic populations of bark beetles (Coleoptera, Scolytinae) in spruce forests of the Tatra National Park in Slovakia

Bark beetles are serious pests for forestry in Slovakia. Their outbreaks may have significant ecological and economic impacts on spruce forests. Effective control of bark beetles is difficult due to their cryptic habits, however, microbial control using entomopathogenic fungi is believed to be a promising alternative to traditional control measures. During 2014–2015, diversity and prevalence of entomopathogenic fungi was studied in populations of bark beetles infesting spruce forests affected by windstorms in the Tatra National Park in Slovakia. Three Beauveria species, B. bassiana , B. caledonica and B. pseudobassiana , together with Metapochonia bulbillosa were identified from 271 specimens of three bark beetle species, Ips typographus , Ips amitinus and Pityogenes chalcographus . Beauveria bassiana was the predominant pathogen and infected all three bark beetle species. Phylogenetic analysis identified three phylogenetic groups of B. bassiana in the evaluated host populations. M. bulbillosa was reported for the first time from bark beetle hosts and Slovakia. The prevalence of fungal infection in natural populations of I. typographus was low and varied between 0.07 and 0.72%.

Individual decisions drive the changes in movement patterns of ground beetles between forestry management types

Moving from one habitat to another, the dispersal of individuals has consequences for their conditions, population dynamics and gene flow. Our major motivation was to explore the effects of different forestry treatments, such as preparation (partial) cuts and clear cuts, on the selected population of the forest ground beetle, Carabus coriaceus (Coleoptera: Carabidae). We tagged six individuals (three males and three females) with small radio-transmitters and each was released in the treatment habitat core, at the edges and in the core of control forests respectively. The recorded trajectories were divided into two major movement phases: a random walk and a directional movement using hidden Markov models. Our results revealed that in the core zone of preparation cuts, the random walk and the directional movement were equally distributed in the trajectory. A clear directional movement was observed in the clear cuts suggesting the beetles moved directly toward the adjacent (control) forest interior. The trajectories at the edges of both treatments were dominated by the random walk and so for the controls. These results suggest that forest ground beetles can avoid the forestry treatments especially clear cuts, however edge habitats and (the studied) preparation cuts can mitigate the migration constraints due to their more favorable environmental conditions compared to clear cuts.

Dung beetles in a tight-spot, but not so much: Quick recovery of dung beetles assemblages after low-impact selective logging in Central Brazilian Amazon

Tropical forests are suffering several changes due to human activities. Among these, selective logging may represent a less damaging alternative, although it may alter species compositions of animals and plants in forest ecosystems. Dung beetles (Coleoptera: Scarabaeinae) are used as bioindicators as they respond quickly to environmental changes. Thus, in this study, we tested the effects of time after logging and seasonality on species richness, number of individuals, and assemblage structure of dung beetles in central Brazilian Amazon Forest. We also identified indicator species of logged and unlogged sites. We used a total of 240 flight interception traps (20 per area) in 11 logged sites (between one and 15 years after logging) and one unlogged site. We collected 28,508 dung beetles from 85 species. Most individuals (24,349, 85.41%) were collected during the dry period. Four species were good indicators of the unlogged site, while 21 species were indicators of logged sites. Time after logging and seasonality significantly affected species richness, the number of individuals collected, and assemblage structure. These effects were more significant from the second to the fifth year after logging. Logged sites represented 77% to 95% of species richness in the unlogged site. From the sixth year after logging, dung beetle assemblages were significantly recovered. Our results show that low-impact selective logging practices in sustainable forest sites may not cause irreversible impacts on dung beetle diversity.

Rainfall seasonality drives the spatiotemporal patterns of dung beetles in Amazonian forests in the arc of deforestation

The Amazon Rainforest is facing high rates of deforestation, leaving anthropogenically dominated landscapes across the Amazon. Understanding the biodiversity response to the effects of rainfall seasonality can provide important examples of how species may respond to drastic climate conditions in anthropogenic landscapes. Here, we sampled dung beetles across the same Amazon forest sites during the rainy and dry seasons to evaluate the effect of seasonality on biodiversity patterns. We found a significant space–time interaction for the whole set of forest sites indicating that the spatial structure of the species abundance data has changed significantly between seasons. Dung beetle abundance and species richness was higher in the rainy season when evaluating all species and separately for nesting behavior group. For presence-absence and abundance data of the whole assemblage, the mean differences between losses and gains over all forest sites was negative, indicating dominance of species and individuals-per-species losses across all forest sites. Eleven species (5 tunnellers, 4 rollers, and 2 dwellers) had significant decreases in abundances in the forest sites from the rainy to the dry season, whereas one roller species increased in abundance from the rainy to the dry season. Rainfall seasonality drives the temporal patterns of dung beetle diversity in the Amazonian forests in the study region in the arc of deforestation. Understanding species vulnerability to changes in climatic conditions could help to predict species distributions in an increased scenario of higher temperatures and longer drought periods during dry seasons in the near future.

Monoculture and mixture-planting of non-native Douglas fir alters species composition, but promotes the diversity of ground beetles in a temperate forest system

Planting non-native tree species, like Douglas fir in temperate European forest systems, is encouraged to mitigate effects of climate change. However, Douglas fir monocultures often revealed negative effects on forest biota, while effects of mixtures with native tree species on forest ecosystems are less well understood. We investigated effects of three tree species (Douglas fir, Norway spruce, native European beech), on ground beetles in temperate forests of Germany. Beetles were sampled in monocultures of each tree species and broadleaf-conifer mixtures with pitfall traps, and environmental variables were assessed around each trap. We used linear mixed models in a two-step procedure to disentangle effects of environment and tree species identity on ground beetle abundance, species richness, functional diversity and species assemblage structure. Contradictory to our expectations, ground beetle abundance and functional diversity was highest in pure Douglas fir stands, while tree mixtures showed intermediate values between pure coniferous and pure beech stands. The main drivers of these patterns were only partially dependent on tree species identity, which highlights the importance of structural features in forest stands. However, our study revealed distinct shifts in assemblage structure between pure beech and pure Douglas fir stands, which were only partially eased through mixture planting. Our findings suggest that effects of planting non-native trees on associated biodiversity can be actively modified by promoting beneficial forest structures. Nevertheless, integrating non-native tree species, even in mixtures with native trees, will invariably alter assemblage structures of associated biota, which can compromise conservation efforts targeted at typical species composition.

Abundance, distribution and substrate association of Hong Kong stag beetles (Coleoptera: Lucanidae) in secondary forests

Abstract Ecological studies conducted on lucanids in Asia are limited, resulting in considerable knowledge gaps in the fundamental ecology of these charismatic species (e.g. larval substrate associations), despite their potential importance in wood decomposition. We conducted 25 transect surveys in secondary forest sites in Hong Kong and sampled wood parameters and site‐level wood availability data to test whether these habitat features significantly affected abundance or occurrence of lucanids. Out of 412 wood fragments sampled, we found two species: Prosopocoilus oweni was broadly distributed across sites (but still uncommon at the level of wood fragments occurring in 6.07%) while Nigidius sinicus was comparatively rarer (occurring in 0.73% of examined wood fragments). The dominant species P. oweni was more likely to appear in wood fragments in later decay stages and can be classified as a secondary forest generalist with respect to wood resource utilisation. The surveys failed to detect four additional lucanid species known in Hong Kong (Neolucanus sinicus, E. gracilis, P. biplagiatus, and Aegus chelifer) potentially because of their rarity or usage of other habitats or microhabitats. Protection of existing secondary forests in Hong Kong is recommended to secure supply of suitable habitat and resources. Results obtained by standardised surveys can furthermore serve as a baseline for future assessment of lucanid population change. This study provides ecological insights into lucanids within secondary forest ecosystems of subtropical and tropical Asia.

Tropical land-use change alters trait-based community assembly rules for dung beetles and birds

Tropical rainforest disturbance and conversion are critical drivers of biodiversity loss. A key knowledge gap is understanding the impacts of habitat modification on mechanisms of community assembly, which are predicted to respond differently between taxa and across spatial scales. We use a null model approach to detect trait assembly of species at local- and landscape-scales, and then subdivide communities with different habitat associations and foraging guilds to investigate whether the detection of assembly mechanisms varies between groups. We focus on two indicator taxa, dung beetles and birds, across a disturbance gradient of primary rainforest, selectively logged rainforest, and oil palm plantations in Borneo, Southeast Asia. Random community assembly was predominant for dung beetles across habitats, whereas trait convergence, indicative of environmental filtering, occurred across the disturbance gradient for birds. Assembly patterns at the two spatial scales were similar. Subdividing for habitat association and foraging guild revealed patterns hidden when focusing on the overall community. Dung beetle forest specialists and habitat generalists showed opposing assembly mechanisms in primary forest, community assembly of habitat generalists for both taxa differed with disturbance intensity, and insectivorous birds strongly influenced overall community assembly relative to other guilds. Our study reveals the sensitivity of community assembly mechanisms to anthropogenic disturbance via a shift in the relative contribution of stochastic and deterministic processes. This highlights the need for greater understanding of how habitat modification alters species interactions and the importance of incorporating species’ traits within assessments.

Climate Change Effects on Trophic Interactions of Bark Beetles in Inner Alpine Scots Pine Forests

Increased tree mortality has become a widespread phenomenon and is largely attributed to climate change. Little field research has addressed the complex interactions between trees, herbivores, and their natural enemies as affected by temperature. We recorded the densities of bark insects and their natural enemies emerging from felled trees in Scots pine forests at 17 study sites along 6 elevation gradients encompassing different temperature ranges in 3 regions in Switzerland and Italy. We additionally measured tree resin defense at different elevations. The density of aggressive bark beetles decreased with increasing temperatures while that of non-aggressive species did not respond to temperature. Contrasting patterns were also found for natural enemies, with the densities of most predatory taxa decreasing with increasing temperature whereas densities of parasitoids increased. Consequently, bark beetle mortality by predators decreased and that by parasitoids increased with temperature. Exudation of resin increased with temperature. As the number of resin ducts did not change with temperature, this is assumed a physical effect of reduced viscosity. Despite lower densities of aggressive bark beetles and improved tree resin flow under higher temperatures, the currently experienced drought-induced reduction in tree vigor is likely to increase tree mortality under the ongoing climate warming.

The Characteristics of Chemosensory and Opsin Genes in Newly Emerged and Sexually Mature Agrilus planipennis, an Important Quarantine Forest Beetle.

The emerald ash borer (EAB), Agrilus planipennis, is a highly destructive quarantine pest. The olfactory and visual systems of A. planipennis play different but critical roles at newly emerged and sexually mature stages; however, the molecular basis underlying these differences remain unclear. Consequently, based on deep transcriptome sequencing, we evaluated the expression levels of chemosensory-related proteins and opsins at the two developmental stages of A. planipennis. We found 15 new chemosensory-related genes in our transcriptome assembly compared with the previous genome assembly, including 6 that code for odorant-binding proteins (OBPs) and 9 for chemosensory proteins (CSPs). The expression of several chemosensory-related genes (OBP7, OBP10, CSP1, and CSP12) differed markedly between newly emerged and sexually mature A. planipennis. We also found that the expression of UV opsin 2 and LW opsin 1 was higher in sexually mature male A. planipennis, which may be associated with their strong visual mate detection ability. This study forms the basis for further investigation of the chemosensory and visual system of A. planipennis, and these differentially expressed genes between newly emerged and sexually mature stages may serve as targets for the management of this destructive forest pest after sexual maturity.

Habitat type and altitude work in tandem to drive the community structure of dung beetles in Afromontane forest

Dung beetles are a species group highly recognized for their sensitivity to anthropogenically induced change. There are few studies of the dung beetle communities found in Afromontane forests despite these forests forming part of a global hotspot of biodiversity. We used comparisons of diversity to investigate the effect of habitat and altitude on the species composition of Scarabaeidae dung beetles in six Afromontane habitat types and identified indicator species associated with each forest type. A total of 8020 individuals from 34 species belonging to 16 genera were captured at twelve transect locations across a 1.5 km altitudinal gradient. All indices measuring diversity and dominance showed significant differences between forest types with little overlap in the species composition detected in each. Altitude was negatively correlated with dung beetle abundance, species richness, and diversity, and there were also significant differences in abundance, species richness and diversity between altitude zones. Eight indicator species were identified for potential use in future conservation management or monitoring programs. This study found no significant relationship between species richness and forest type but an interaction between the two factors. Altitude in conjunction with forest type are the main factors in shaping dung beetle species composition in this Afromontane forest. Our results suggest the most important characteristic for determining community structure was mean canopy cover per forest type. Results from a previous short study conducted in 1974 indicate while there was significant overlap between dung beetle species caught 40 years ago and the present day there were also seven species which were absent. All seven of these species have climatic distributions centered around the wet highlands of East Africa and further work is urgently required to understand why these species are no longer detectable in the ANP. Our results have important conservation implications as they underscore the importance of preserving forest heterogeneity to maintain maximum dung beetle diversity within mountain ecosystems. The identified differences in dung beetle diversity between forest types and the high turnover of dung beetle species between altitude zones should heighten the importance for instigating future Scarabaeidae conservation initiatives in Afromontane regions.

Evidence for passive dispersal of ground beetles (Coleoptera: Carabidae) in the Nearctic boreal forest

ABSTRACT Passive transport has likely contributed to the post-glacial dispersal of species in temperate regions. However, identifying such processes from patterns can be obscured by confounding environmental conditions. We studied the distribution of ground beetles in Ontario’s Far North, a vast (450,000 km2) and largely intact region, to identify mechanisms that aid in species dispersal when confounding factors, such as temperature, are controlled. We tested a model of passive, riverine dispersal using recent records of flightless and flighted ground beetles from 34 sites across the region. The number of species declined with distance from main watershed rivers, as predicted from our model at the site level. Contrary to expectations, this pattern was evident with flighted species but not flightless species. The opposite pattern, with flightless species displaying a decrease with increasing distance from river, was evident at a regional level. These patterns are consistent with ground beetles carried along rivers since glacial retreat. We surmise that northward dispersal of these invertebrates into the boreal forest has been aided by vegetation and other debris flowing down rivers, including soil from eroded banks in which larvae and pupae reside. Biogeographic inferences, although often subtle, can be supported by broad-scale studies of intact landscapes.

Coleotteri del legno e microhabitat forestali nei boschi misti di abete bianco e faggio della Riserva di Vallombrosa

Forest biodiversity can be monitored trough ecological indicators, such as microhabitats and dead wood. Among the primary users of these small habitats there are arthropods, birds and mammals, but the most important component is represented by Coleoptera. In 2020, a study was launched in the mixed forests of silver fir and beech in the Nature Reserve of Vallombrosa in order to examine the saproxylic beetles present and the relationships between these species and indicators of forest biodiversity. In 47 plots, we sampled flying and crawling beetles, assessed the microhabitats and measured the volumes of dead wood and living trees. In this paper we report the first results obtained from the study. In the examined stands, we found threatened and endangered species included in the Red List of Italian Saproxylic Beetles and species protected under the Habitat Directive. A total of 2573 microhabitats were surveyed and proved to have ecological relationships with the sampled beetle species. The percentage ratio between the volume of dead wood and the volume of living trees was 39%. The results are discussed to describe the ecological role of the saproxylic beetles with respect to the biodiversity indicators. Saproxylic Beetles and microhabitats in mixed forests of silver firand beech in the Vallombrosa ReserveSaproxylic Beetles and microhabitats in mixed forests of silver firand beech in the Vallombrosa Reserve

Patterns of richness across forest beetle communities-A methodological comparison of observed and estimated species numbers.

Species richness is a frequently used measure of biodiversity. The compilation of a complete species list is an often unattainable goal. Estimators of species richness have been developed to overcome this problem. While the use of these estimators is becoming increasingly popular, working with the observed number of species is still common practice.To assess whether patterns of beetle communities based on observed numbers may be compared among each other, we compared patterns from observed and estimated numbers of species for beetle communities in the canopy of the Leipzig floodplain forest. These patterns were species richness and the number of shared species among three tree species and two canopy strata.We tested the applicability of the asymptotic Chao1 estimator and the estimate provided by the nonasymptotic rarefaction–extrapolation method for all tree species and both upper canopy and lower canopy. In the majority of cases, the ranking patterns of species richness for host tree species and strata were the same for the observed and estimated number of species. The ranking patterns of the number of species shared among host tree species and strata, however, were significantly different between observed and estimated values.Our results indicate that the observed number of species under‐represents species richness and the number of shared species. However, ranking comparisons of published patterns based on the number of observed species may be acceptable for species richness but likely not reliable for the number of shared species. Further studies are needed to corroborate this conclusion. We encourage to use estimators and to provide open access to data to allow comparative assessments.

Diversity of beetles (Coleoptera) in natural and planted saxaul forests (Haloxylon ammodendron) in the South Gobi Desert, Mongolia.

We investigated species composition and diversity parameters of beetle communities in two planted saxaul (Haloxylon ammodendron, black saxaul) forests in Southern Mongolia. We also studied nearby natural areas for comparison. Beetles were mainly collected by pitfall traps. 1064 individuals of 38 species of 22 genera in 4 beetle families were identified from planted plots. In comparison, a total of 1395 beetles belonging to 40 species of 24 genera in seven families were collected and identified from the natural saxaul plots. The most diverse beetle families were darkling beetles (Tenebrionidae, 18 species) and snout beetles (Curculionidae, 15 species) in planted and natural saxaul plots. We recorded several species (Apatophysis serricornis, Cephogenia chinensis, and Eumylada punctifera punctifera) which are associated with the saxaul tree. A darkling beetle, Anatolica potanini, was the dominant species in both natural and planted plots of the Nariin Zag forest. There were significant differences in the species richness and abundance between the planted and natural plots of the Ukhaa Zag forest. It is possible that the age of the plantation drove the differences. The higher values of diversity indices and species richness in the planted plots can be explained by the presence of rare species, represented by only one or two individuals. The planted plots and corresponding natural plots within each forest were more similar to each other in species composition and abundance than between forests.

A first faunistic study on the tribe Oniticellini Kolbe, 1905 (Coleoptera: Scarabaeidae) of Baikunthapur Tropical Forest of the Himalayan foothills, West Bengal, India.

BackgroundOniticellini Kolbe, 1905 is a paucispecific tribe of the scarab beetle subfamily Scarabaeinae. The tribe is composed of 256 described species worldwide, while from India, 26 species were recorded to date. Beetles belonging to this tribe are commonly known as paracoprid dung beetles and perform some remarkable ecological functions. Nevertheless, there is a dearth of knowledge on the occurrence of these beetles in the mega diverse tropical forests of the Himalayan foothills located in the north of the West Bengal state of India.New informationA first faunistic account of the tribe Oniticellini Kolbe, 1905 from Baikunthapur Forest, located at the Himalayan foothills of the West Bengal state of India is presented. A total of five species of the tribe distributed over two genera Tiniocellus and Liatongus were recorded during multiple surveys of the scarab fauna of the Forest. All taxa were recorded for the first time from the area, while Tiniocellus spinipes (Roth, 1851) is a new record for the West Bengal State of India. Additionally, a preliminary checklist of Indian species of the tribe is also provided.

Effects of Environmental Traits and Landscape Management on the Biodiversity of Saproxylic Beetles in Mediterranean Oak Forests

This study assesses the effects of environmental traits and landscape management on the biodiversity of saproxylic beetles from “dehesas” located in Sierra Morena Mountains (Córdoba, Southern Iberian Peninsula). The dehesa is an open savanna-like landscape with mature/old trees scattered on a pasture cover where both living and dead wood are of great importance for the maintenance of macroinvertebrate fauna. The study was carried out in five plots, with different environmental features and management. A total of 137 branches belonging to the four main tree species present in the area were collected, classified, and kept under four different thermal conditions. From January to June 2019, the adult emergences were followed. A total of 466 saproxylic specimens of 31 species were obtained, 5 of them included in red lists of protected fauna. Two Bostrichidae species (Lichenophanes numida Lesne and Scobicia pustulata Fab.) and two Cerambycidae (Chlorophorus ruficornis Oliv. and Trichoferus fasciculatus Faldermann) are included in the “European Red List of Saproxylic Beetles”; and the Clerid Tillus ibericus Bahillo de la Puebla, López–Colón and García–Paris, is included in the “Red Book of Invertebrate of Andalucía”. Differences were observed regarding the diversity and abundance among the plots and among the tree species from which the beetles emerged. Simple regression analyses revealed negative relationships between tree density/Buprestidae, livestock/Bostrichidae, and land use/Cerambycidae. Multivariant logistic regression analysis did not find significant relationships among environmental traits and saproxylic diversity. Results confirmed that dry wood was a main resource for the maintenance dehesas’ biodiversity because it constitutes an ecological niche exploited by a significant set of saproxylic beetles belonging to the Bostrichidae, Buprestidae, and Cerambycidae families, in addition to other guilds of species, mainly Carabidae and Cleridae, which feed on the above-mentioned groups. Our results also support that increasing environmental temperature accelerates the development of Buprestidae, but this effect was not evident for the Bostrichidae species.

Communities of ground beetles (Carabidae, Coleoptera) in broad-leaved forests of protected and urban areas of the Kaluga Oblast (European Russia).

BackgroundThis sampling-event dataset provides primary data about species diversity, population and seasonal activity of ground beetles (Carabidae, Coleoptera). The study was carried out in broad-leaved forests of protected ("Kaluzhskiye Zaseki" Nature Reserve and Ugra National Park) and urban areas (the Kaluga City) of the Kaluga Oblast. Carabids were collected from April to October during 1995-1998 by pitfall traps. In total, 108,000 adult individuals of the Carabidae family were sampled; 105 species from 38 genera were counted.New informationThis dataset is the first sampling-event dataset about the Carabidae family for the European part of Russia. It provides biodiversity data for new territory (Kaluga Oblast) and contributes to filling gaps in the global biodiversity distribution of the Carabidae family. Part of the data was collected from unique old-growth broad-leaved forests.

Monitoring Bark Beetle Forest Damage in Central Europe. A Remote Sensing Approach Validated with Field Data

Over the last decades, climate change has triggered an increase in the frequency of spruce bark beetle (Ips typographus L.) in Central Europe. More than 50% of forests in the Czech Republic are seriously threatened by this pest, leading to high ecological and economic losses. The exponential increase of bark beetle infestation hinders the implementation of costly field campaigns to prevent and mitigate its effects. Remote sensing may help to overcome such limitations as it provides frequent and spatially continuous data on vegetation condition. Using Sentinel-2 images as main input, two models have been developed to test the ability of this data source to map bark beetle damage and severity. All models were based on a change detection approach, and required the generation of previous forest mask and dominant species maps. The first damage mapping model was developed for 2019 and 2020, and it was based on bi-temporal regressions in spruce areas to estimate forest vitality and bark beetle damage. A second model was developed for 2020 considering all forest area, but excluding clear-cuts and completely dead areas, in order to map only changes in stands dominated by alive trees. The three products were validated with in situ data. All the maps showed high accuracies (acc > 0.80). Accuracy was higher than 0.95 and F1-score was higher than 0.88 for areas with high severity, with omission errors under 0.09 in all cases. This confirmed the ability of all the models to detect bark beetle attack at the last phases. Areas with no damage or low severity showed more complex results. The no damage category yielded greater commission errors and relative bias (CEs = 0.30–0.42, relB = 0.42–0.51). The similar results obtained for 2020 leaving out clear-cuts and dead trees proved that the proposed methods could be used to help forest managers fight bark beetle pests. These biotic damage products based on Sentinel-2 can be set up for any location to derive regular forest vitality maps and inform of early damage.

Dispersal barriers and opportunities drive multiple levels of phylogeographic concordance in the Southern Alps of New Zealand.

Phylogeographic concordance, or the sharing of phylogeographic patterns among codistributed species, suggests similar responses to topography or climatic history. While the orientation and timing of breaks between lineages are routinely compared, spatial dynamics within regions occupied by individual lineages provide a second opportunity for comparing responses to past events. In environments with complex topography and glacial history, such as New Zealand's South Island, geographically nested comparisons can identify the processes leading to phylogeographic concordance between and within regional genomic clusters. Here, we used single nucleotide polymorphisms (obtained via ddRADseq) for two codistributed forest beetle species, Agyrtodes labralis (Leiodidae) and Brachynopus scutellaris (Staphylinidae), to evaluate the role of climate change and topography in shaping phylogeographic concordance at two, nested spatial scales: do species diverge over the same geographic barriers, with similar divergence times? And within regions delimited by these breaks, do species share similar spatial dynamics of directional expansion or isolation-by-distance? We found greater congruence of phylogeographic breaks between regions divided by the strongest dispersal barriers (i.e., the Southern Alps). However, these shared breaks were not indicative of shared spatial dynamics within the regions they delimit, and the most similar spatial dynamics between species occurred within regions with the strongest gradients in historical climatic stability. Our results indicate that lack of concordance as traditionally detected by lineage turnover does not rule out the possibility of shared histories, and variation in the presence and type of concordance may provide insights into the different processes shaping phylogeographic patterns across geologically dynamic regions.