Nicolai Benjamin Aall

The threat of invasive species to biodiversity and ecosystem structure is exacerbated by the increasingly concerning outlook of predicted climate change and other human influences. Developing preventative management strategies for invasive plant species before they establish is crucial for effective management. To examine how climate change may impact habitat suitability, we modeled the current and future habitat suitability of two terrestrial species, Geranium lucidum and Pilosella officinarum , and two aquatic species, Butomus umbellatus and Pontederia crassipes , that are relatively new invasive plant species regionally, and are currently spreading in the Pacific Northwest (PNW, North America), an area of unique natural areas, vibrant economic activity, and increasing human population. Using North American presence records, downscaled climate variables, and human influence data, we developed an ensemble model of six algorithms to predict the potential habitat suitability under current conditions and projected climate scenarios RCP 4.5, 7.0, and 8.5 for 2050 and 2080. One terrestrial species ( P. officinarum ) showed declining habitat suitability in future climate scenarios (contracted distribution), while the other terrestrial species ( G. lucidum ) showed increased suitability over much of the region (expanded distribution overall). The two aquatic species were predicted to have only moderately increased suitability, suggesting aquatic plant species may be less impacted by climate change. Our research provides a template for regional-scale modelling of invasive species of concern, thus assisting local land managers and practitioners to inform current and future management strategies and to prioritize limited available resources for species with expanding ranges.

Species' thermal tolerances are used to estimate climate vulnerability, but few studies consider the role of the hydric environment in shaping thermal tolerances. As environments become hotter and drier, organisms often respond by limiting water loss to lower the risk of desiccation; however, reducing water loss may produce trade‐offs that lower thermal tolerances if respiration becomes inhibited. Here, we measured the sensitivity of water loss rate and critical thermal maximum (CTmax) to precipitation in nature and laboratory experiments that exposed click beetles (Coleoptera: Elateridae) to acute‐ and long‐term humidity treatments. We also took advantage of their unique clicking behavior to characterize subcritical thermal tolerances. We found higher water loss rates in the dry acclimation treatment compared to the humid, and water loss rates were 3.2‐fold higher for individuals that had experienced a recent precipitation event compared to individuals that had not. Acute humidity treatments did not affect CTmax, but precipitation indirectly affected CTmax through its effect on water loss rates. Contrary to our prediction, we found that CTmax was negatively associated with water loss rate, such that individuals with high water loss rate exhibited a lower CTmax. We then incorporated the observed variation of CTmax into a mechanistic niche model that coupled leaf and click beetle temperatures to predict climate vulnerability. The simulations indicated that indices of climate vulnerability can be sensitive to the effects of water loss physiology on thermal tolerances; moreover, exposure to temperatures above subcritical thermal thresholds is expected to increase by as much as 3.3‐fold under future warming scenarios. The correlation between water loss rate and CTmax identifies the need to study thermal tolerances from a “whole‐organism” perspective that considers relationships between physiological traits, and the population‐level variation in CTmax driven by water loss rate complicates using this metric as a straightforward proxy of climate vulnerability.

Aim Understanding biodiversity patterns is crucial for prioritizing future conservation efforts and reducing the current rates of biodiversity loss. However, a large proportion of species remain undescribed (i.e. unknown biodiversity), hindering our ability to conduct this task. This phenomenon, known as the ‘Linnean shortfall’, is especially relevant in highly diverse, yet endangered, taxonomic groups, such as insects. Here we explore the distributions of recently described freshwater insect species in Europe to (1) infer the potential location of unknown biodiversity hotspots and (2) determine the variables that can anticipate the distribution of unknown biodiversity. Location The European continent, including western Russia, Cyprus and Turkey. Methods Georeferenced information of all sites where new aquatic insect species were described across Europe from 2000 to 2020 was compiled. In order to understand the observed spatial patterns in richness of recently described species, spatial units were defined (level 6 of HydroBASINS) and associated with a combination of a set of socioeconomic, environmental and sampling effort descriptors. A zero-inflated Poisson regression approach was used to model the richness of newly described species within each spatial unit. Results Nine hundred and sixty-six recently described species were found: 398 Diptera, 362 Trichoptera, 105 Coleoptera, 66 Plecoptera, 28 Ephemeroptera, 3 Neuroptera, 2 Lepidoptera and 2 Odonata. The Mediterranean Basin was the region with the highest number of recently described species (74%). The richness of recently described species per spatial unit across Europe was highest at mid-elevation areas (between 400 and 1000 m), latitudes between 40 and 50° and in areas with yearly average precipitation levels of 500–1000 mm, a medium intensity of sampling effort and low population density. The percentage of protected areas in each study unit was not significantly related to the richness of recently described species. In fact, 70% of the species were found outside protected areas. Main conclusions The results highlight the urgent need to concentrate conservation efforts in freshwater ecosystems located at mid-altitude areas and out of protected areas across the Mediterranean Basin. The highest number of newly described species in those areas indicates that further monitoring efforts are required to ensure the aquatic biodiversity is adequately known and managed within a context of growing human impacts in freshwater ecosystems.

Abstract How many species are there on Earth and to what groups do these species belong? These fundamental questions span systematics, ecology, and evolutionary biology. Yet, recent estimates of overall global biodiversity have ranged wildly, from the low millions to the trillions. Insects are a pivotal group for these estimates. Insects make up roughly half of currently described extant species (across all groups), with ~1 million described species. Insect diversity is also crucial because many other taxa have species that may be unique to each insect host species, including bacteria, apicomplexan protists, microsporidian fungi, nematodes, and mites. Several projections of total insect diversity (described and undescribed) have converged on ~6 million species. However, these projections have not incorporated the morphologically cryptic species revealed by molecular data. Here, we estimate the extent of cryptic insect diversity. We perform a systematic review of studies that used explicit species-delimitation methods with multi-locus data. We estimate that each morphology-based insect species contains (on average) 3.1 cryptic species. We then use these estimates to project the overall number of species on Earth and their distribution among major groups. Our estimates suggest that overall global biodiversity may range from 563 million to 2.2 billion species. [Biodiversity; cryptic species; insects; species delimitation; species richness]

The genus Brachysomus Schoenherr, 1823 is reviewed. A comparative morphological study of adults from 56 Brachysomus species is provided. Redescriptions, diagnoses and identification keys are given. Descriptions of two new species are provided: B. (s. str.) podlussanyi sp. n. from Greece and B. (s. str.) pseudosetiger sp. n. from Bulgaria, which appear to be closely related to B. (s. str.) mihoki Penecke, 1914. Females of B. (s. str.) longipterus Białooki, 2007 are described. The poorly known B. (Hippomias) moczarskii Penecke, 1924 is restored from synonymy with B. (H.) oertzeni Faust, 1889. New synonyms: B. (s. str.) echinatus (Bonsdorff, 1785) = B. (s. str.) hirsutus Iablokoff-Khnzorian, 1958 syn. n. New combinations: Brachysomus (s. str.) lituratus (Reitter, 1884) comb. n. from Foucartia Jacquelin du Val, 1854; Eurosphalmus tenuicollis (Yunakov, 2006) comb. n. from Brachysomus, Eurosphalmus cribrarius (Białooki, 2007) comb. n. from Brachysomus, Nanomias skodai (Białooki, 2007) comb. n. from Brachysomus, and Chiloneus bonnairei (Hoffmann, 1942) comb. n. from Brachysomus. Lectotypes are designated for: Strophosomus hirtus Boheman, 1845; Brachysomus ornatus Stierlin, 1892; B. bensae Stierlin, 1893; Platytarsus fasciatus Stierlin, 1899; and P. setiger Gyllenhal, 1840. For each species, all known localities are presented on a distribution map. Ecological preferences of Brachysomus species are specified. First records of Brachysomus (s. str.) fremuthi Košťál, 1991 from Romania, B. (Hippomias) carpathicus Košťál, 1992 from Serbia, and B. (H.) ponticus Apfelbeck, 1898 from Greece are given.

Largely assisted by global trade, alien insect species are being introduced into new territories at unprecedented rates. Among forest insects, pine bark beetles (Coleoptera: Curculionidae, Scolytinae) are a large and diverse group commonly recognized as successful invaders and important tree mortality agents in pine forests and commercial plantations. In this study, we collected information on the native and invaded distribution of 51 European bark beetles developing in Pinus species. We analyzed their invasion history in the Southern Hemisphere and the Americas and explored several factors that can help explain their invasion success: (1) propagule pressure: interception frequency in the non-native range(2) invasibility: potential establishment area based on climatic matching and host availability and (3) invasiveness: biological traits of the bark beetles ( i.e. , feeding habit, host range, body size, mating system, colonization behavior). We found that most (87%) of the introductions of the species to new regions occurred in the period 1960–2013, and that variables related with the three main factors were relevant in explaining invasion success. Propagule pressure was the factor that best explained bark beetle invasion probability, followed by invasibility of the novel area. In turn, biological attributes like mating system, body size and host range were also relevant, but showed a lower relative importance. Our study contributes to understand the main factors that explain forest insect invasion success. This information is critical for predicting future invasions to new regions and optimizing early-detection and biosecurity policies.

Abstract. Statistical climate reconstruction techniques are fundamental tools to study past climate variability from fossil proxy data. In particular, the methods based on probability density functions (or PDFs) can be used in various environments and with different climate proxies because they rely on elementary calibration data (i.e. modern geolocalised presence data). However, the difficulty of accessing and curating these calibration data and the complexity of interpreting probabilistic results have often limited their use in palaeoclimatological studies. Here, I introduce a new R package (crestr) to apply the PDF-based method CREST (Climate REconstruction SofTware) on diverse palaeoecological datasets and address these problems. crestr includes a globally curated calibration dataset for six common climate proxies (i.e. plants, beetles, chironomids, rodents, foraminifera, and dinoflagellate cysts) associated with an extensive range of climate variables (20 terrestrial and 19 marine variables) that enables its use in most terrestrial and marine environments. Private data collections can also be used instead of, or in combination with, the provided calibration dataset. The package includes a suite of graphical diagnostic tools to represent the data at each step of the reconstruction process and provide insights into the effect of the different modelling assumptions and external factors that underlie a reconstruction. With this R package, the CREST method can now be used in a scriptable environment and thus be more easily integrated with existing workflows. It is hoped that crestr will be used to produce the much-needed quantified climate reconstructions from the many regions where they are currently lacking, despite the availability of suitable fossil records. To support this development, the use of the package is illustrated with a step-by-step replication of a 790 000-year-long mean annual temperature reconstruction based on a pollen record from southeastern Africa.

The aim of this study was to evaluate the impact of global warming on suitable niches of montane orchid, Traunsteinera globosa, using ecological niche modelling approach. Additionally, the effect of various climate change scenarios on future changes in the distribution and overlap of the orchid magn…

The Qinghai-Tibetan Plateau (QTP) harbors abundant and diverse plant life owing to its high habitat heterogeneity. However, the distribution pattern of biodiversity hotspots and their conservation status remain unclear. Based on 148,283 high-resolution occurrence coordinates of 13,450 seed plants, w…

Understanding the impact of historical and demographic processes on genetic variation is essential for devising conservation strategies and predicting responses to climate change. Recolonization after Pleistocene glaciations is expected to leave distinct genetic signatures, characterised by lower ge…