Search

Global biodiversity loss is a profound consequence of human activity. Disturbingly, biodiversity loss is greater than realized because of the unknown number of undocumented species. Conservation fundamentally relies on taxonomic recognition of species, but only a fraction of biodiversity is described. Here, we provide a new quantitative approach for prioritizing rigorous taxonomic research for conservation. We implement this approach in a highly diverse vertebrate group-Australian lizards and snakes. Of 870 species assessed, we identified 282 (32.4%) with taxonomic uncertainty, of which 17.6% likely comprise undescribed species of conservation concern. We identify 24 species in need of immediate taxonomic attention to facilitate conservation. Using a broadly applicable return-on-investment framework, we demonstrate the importance of prioritizing the fundamental work of identifying species before they are lost.

Monitoring the extent to which invasive alien species (IAS) negatively impact the environment is crucial for understanding and mitigating biological invasions. Indeed, such information is vital for achieving Target 6 of the Kunming–Montreal Global Biodiversity Framework. However, to-date indicators for tracking the environmental impacts of IAS have been either lacking or insufficient. Capitalizing on advances in data availability and impact assessment protocols, we developed environmental impact indicators to track realized and potential impacts of IAS. We also developed an information status indicator to assess the adequacy of the data underlying the impact indicators. We used data on 75 naturalized amphibians from 82 countries to demonstrate the indicators at a global scale. The information status indicator shows variation in the reliability of the data and highlights areas where absence of impact should be interpreted with caution. Impact indicators show that growth in potential impacts are dominated by predatory species, while potential impacts from both predation and disease transmission are distributed worldwide. Using open access data, the indicators are reproducible and adaptable across scales and taxa and can be used to assess global trends and distributions of IAS, assisting authorities in prioritizing control efforts and identifying areas at risk of future invasions. This article is part of the theme issue 'Ecological novelty and planetary stewardship: biodiversity dynamics in a transforming biosphere'. [ABSTRACT FROM AUTHOR]

The world is facing a biodiversity crisis, and species are in danger of slipping towards extinction before having their conservation status formally determined. Australian squamates (snakes and lizards) form a highly diverse (over 1000 species) fauna, with 12% being either Data Deficient or Not Evaluated. We examined attributes of Australian squamates categorized as Data Deficient or Not Evaluated and compared key traits that are linked with threatened categories via univariate and multivariate models. We further used the machine learning model of Caetano et al. (2022, PloS Biology, 20, e3001544) to predict the putative extinction risk categories for Data Deficient and Not Evaluated Australian squamate species based on an analysis of reptiles globally. We found that Data Deficient Australian squamates are often lacking information on their drivers of threat and distribution, but not intrinsic traits or uncertain taxonomy. Data Deficient, Not Evaluated and threatened species often possess similar traits, including having small range sizes, being insular endemics and recently described, indicating that they may require some similar conservation management. Meanwhile, Not Evaluated species exhibit certain unique traits relative to evaluated species. We predicted 21% of Data Deficient and Not Evaluated species are threatened which is three times greater than currently assessed species (7%). This may indicate that a larger proportion of poorly known squamate species are more likely to be threatened than previously thought. Overall, our findings provide an important resource for the conservation management of Australian squamates by highlighting key traits and missing data, as well as providing a list of Data Deficient and Not Evaluated species that should be prioritized for research. [ABSTRACT FROM AUTHOR]

Species distribution models (SDMs) are increasingly proposed to support conservation decision making. However, evidence of SDMs supporting solutions for on-ground conservation problems is still scarce in the scientific literature. Here, we show that successful examples exist but are still largely hidden in the grey literature, and thus less accessible for analysis and learning. Furthermore, the decision framework within which SDMs are used is rarely made explicit. Using case studies from biological invasions, identification of critical habitats, reserve selection and translocation of endangered species, we propose that SDMs may be tailored to suit a range of decision-making contexts when used within a structured and transparent decision-making process. To construct appropriate SDMs to more effectively guide conservation actions, modellers need to better understand the decision process, and decision makers need to provide feedback to modellers regarding the actual use of SDMs to support conservation decisions. This could be facilitated by individuals or institutions playing the role of 'translators' between modellers and decision makers. We encourage species distribution modellers to get involved in real decision-making processes that will benefit from their technical input; this strategy has the potential to better bridge theory and practice, and contribute to improve both scientific knowledge and conservation outcomes.

In animals, the success of particular lineages can be measured in terms of their number of species, the extent of their geographic range, the breadth of their habitats and ecological niches, and the diversity of their morphological and life‐history traits. Here, we review the distribution, ecology, morphology and life history of skinks, a diverse lineage of terrestrial vertebrates. We compared key traits between the three subfamilies of skinks, and between skinks and non‐scincid lizards. There are currently 1743 described species of skink, which represent 24% of global lizard diversity. Since 2010, 16% of lizard descriptions have been of skinks. The centres of skink diversity are in Australia, New Guinea, southeast Asia, Oceania, Madagascar and central Africa. Compared with non‐scincid lizards, skinks have larger distributional ranges, but smaller body sizes. Sexual size dimorphism is rare in skinks. Almost a quarter (23%) of skinks exhibit limb reduction or loss, compared with just 3% of non‐scincid lizards. Skinks are more likely to be viviparous (34% of species) compared with non‐scincids (13%), and have higher clutch/litter sizes than non‐scincids. Although skinks mature later than non‐scincids, their longevity is similar to that exhibited by other lizard groups. Most skinks (88%) are active foragers, and they are more likely to be carnivorous than non‐scincids. Skinks are more likely to be diurnal or cathemeral than other lizard groups, but they generally have lower field body temperatures compared with non‐scincids. The success of skinks appears to be both a result of them hitting upon a winning body plan and ecology, and their capacity to regularly deviate from this body plan and adapt their ecology and life history (e.g. repeated limb reduction and loss, transitions to viviparity) to prevailing conditions. [ABSTRACT FROM AUTHOR]

Climate has a key impact on animal physiology, which in turn can have a profound influence on geographic distributions. Yet, the mechanisms linking climate, physiology and distribution are not fully resolved.Using an integrative framework, we tested the predictions of the climatic variability hypothesis (CVH), which states that species with broader distributions have broader physiological tolerance than range‐restricted species, in a group of Lampropholis skinks (8 species, 196 individuals) along a latitudinal gradient in eastern Australia. We investigated several physiological aspects including metabolism, water balance, thermal physiology, thermoregulatory behaviour and ecological performance.Additionally, to test whether organismal information (e.g. behaviour and physiology) can enhance distribution models, hence providing evidence that physiology and climate interact to shape range sizes, we tested whether species distribution models incorporating physiology better predict the range sizes than models using solely climatic layers.In agreement with the CVH, our results confirm that widespread species can tolerate and perform better at broader temperature ranges than range‐restricted species. We also found differences in field body temperatures, but not thermal preference, between widespread and range‐restricted species. However, metabolism and water balance did not correlate with range size.Biophysical modelling revealed that the incorporation of physiological and behavioural data improves predictions of Lampropholis distributions compared with models based solely on macroclimatic inputs, but mainly for range‐restricted species.By integrating several aspects of the physiology and niche modelling of a group of ectothermic animals, our study provides evidence that physiology correlates with species distributions. Physiological responses to climate are central in establishing geographic ranges of skinks, and the incorporation of processes occurring at local scales (e.g. behaviour) can improve species distribution models. [ABSTRACT FROM AUTHOR]

A series of 1,4-di[2-aryl-1-diazenyl]-trans-2,5-dimethylpiperazines(5a-5m), have been synthesized by the reaction of trans-2,5-dimethylpiperazine with two equivalents of the appropriate diazonium salt. The products have been characterized by IR and NMR spectroscopy, and the molecular composition has been verified by high-resolution EI mass spectrometry with accurate mass measurement of the molecular ion. The presence of stereocenters at C2 and C5 of the piperazine ring in the bis-triazene (5) creates two unique pairs of diastereotopic protons in the methylene groups at positions 3 and 6 of the piperazine ring, as evidenced by the complexity of the NMR spectra, which nevertheless can be fully assigned in some cases, such as the anisyl- (5i) and phenyl- (5j) derivatives. The assignment of the proton and carbon signals in the tolyl- derivative (5h) has been aided by the use of 2D NMR HSQC spectroscopy. These results compare favorably with assignments of proton and carbon signals reported previously for triazenes of type 1 and bis-triazenes of types 3 and 4b. Key words: triazene, piperazine, dimethylpiperazine, bis-triazenes, diazonium salts, NMR spectroscopy, IR spectroscopy, mass spectrometry, diastereotopic relationships, 2D NMR HSQC spectroscopy. Une serie de 1,4-di[2-aryl-1-diazenyl]-trans-2,5-dimethylpiperazines (5a-5m) ont ete synthetisees par reaction de la trans-2,5-dimethylpiperazine avec deux equivalents du sel de diazonium approprie. Les produits ont ete caracterises par spectroscopies IR et RMN et la composition moleculaire verifiee au moyen de la spectrometrie de masse par ionisation electronique a haute resolution en mesurant avec precision la masse de l'ion moleculaire. La presence de stereocentres au niveau des carbones C2 et C5 du cycle de la piperazine dans le bis-triazene (5) entraine la formation de deux paires uniques de protons diastereotopiques dans les groupements methylene aux positions 3 et 6 du meme cycle, comme le montrent la complexite des spectres de RMN. Ceux-ci peuvent etre cependant attribues dans certains cas comme les derives anisyl (5i) and phenyl (5j). L'attribution des signaux du proton et du carbone dans le derive tolyl (5h) a ete facilitee par l'emploi de la spectroscopie HSQC RMN bidimensionnelle. Ces resultats coincident plutot bien avec les attributions des signaux du proton et du carbone observee precedemment dans les cas des triazenes de type 1 et des bis-triazenes de types 3 et 4b. [Traduit par la Redaction] Mots-cles: triazene, piperazine, dimethylpiperazine, bis-triazenes, sels de diazonium, spectroscopie RMN, spectroscopie IR, spectrometrie de masse, relations diastereotopiques, spectroscopie HSQC RMN bidimensionnelle., Introduction In Part I of this series, (1) the diazonium coupling reaction of 1-methylpiperazine was explored to synthesize the 4-methyl-1-(2aryldiazen-1-yl-)piperazines (1). The structure of one compound, namely methyl 4-{(E)-2-(4methylpiperazino)-1-diazenyl}benzoate, in [...]

Background: Fire creates habitats for many animals but changes in fire activity threaten species worldwide. While conservation assessments routinely identify fire as a threat to lizards and snakes, the processes underlying fire‐driven population declines have received less attention. Assessing the effects of fire on demographic processes – survival, reproduction and movement – provides a means to identify mechanisms of population declines and forecast population changes. Here, we synthesize how inappropriate fire regimes contribute to declines of animal populations, using threatened Australian squamates as a case study. Methods: We applied a demographic framework in a systematic review to identify fire characteristics and interacting threats associated with population declines in imperilled Australian squamates (n = 88). We reviewed primary literature and conservation assessments on these species and classified fire‐related threats according to seven key mechanisms of population decline, five fire‐regime characteristics, and eight interacting threats. Results: Inappropriate fire regimes threaten 43% of Australian squamates of conservation concern, including geckos, skinks and snakes. Our analysis indicates that high fire intensity and severity, high fire frequency, and large fires are the main causes of fire‐related population declines, particularly via their impacts on survival. Low fire frequency also contributes to declines of some species through reduced survival or reproductive success. Weed invasion and predation are observed or predicted to interact with fire to amplify reptile declines. Our results also reveal a dearth of robust empirical studies on squamates of conservation concern. Main conclusions: The demographic framework applied here will help forecast population changes in a new era of fire. By focusing on processes that are relevant to squamate populations globally, we anticipate that the framework will help diagnose causes of population declines in ecosystems that experience fire, and quantify the consequences of alternative management actions, including urgent conservation interventions after megafires. [ABSTRACT FROM AUTHOR]

The Red List of Threatened Species, published by the International Union for Conservation of Nature (IUCN), is a crucial tool for conservation decision-making. However, despite substantial effort, numerous species remain unassessed or have insufficient data available to be assigned a Red List extinction risk category. Moreover, the Red Listing process is subject to various sources of uncertainty and bias. The development of robust automated assessment methods could serve as an efficient and highly useful tool to accelerate the assessment process and offer provisional assessments. Here, we aimed to (1) present a machine learning–based automated extinction risk assessment method that can be used on less known species; (2) offer provisional assessments for all reptiles—the only major tetrapod group without a comprehensive Red List assessment; and (3) evaluate potential effects of human decision biases on the outcome of assessments. We use the method presented here to assess 4,369 reptile species that are currently unassessed or classified as Data Deficient by the IUCN. The models used in our predictions were 90% accurate in classifying species as threatened/nonthreatened, and 84% accurate in predicting specific extinction risk categories. Unassessed and Data Deficient reptiles were considerably more likely to be threatened than assessed species, adding to mounting evidence that these species warrant more conservation attention. The overall proportion of threatened species greatly increased when we included our provisional assessments. Assessor identities strongly affected prediction outcomes, suggesting that assessor effects need to be carefully considered in extinction risk assessments. Regions and taxa we identified as likely to be more threatened should be given increased attention in new assessments and conservation planning. Lastly, the method we present here can be easily implemented to help bridge the assessment gap for other less known taxa. The Red List of Threatened Species, published by the IUCN, is a crucial tool for conservation decision making, but is subject to various sources of uncertainty and bias. Modelling the threat status of all global reptiles identifies increased threat to many groups of reptiles across many regions of the world, beyond those currently recognized; moreover, it highlights the effects of the IUCN assessment procedure on eventual threat categories. [ABSTRACT FROM AUTHOR]

Abstract: A series of 1,4-di-[2-aryl-1-diazenyl]-2-methylpiperazines (4a-n) have been synthesized by the reaction of 2-methylpiperazine with 2 equiv. of the appropriate diazonium salt. The products have been characterized by IR and [...]

Abstract: A new series of bistriazenes, the 1-aryl-2-[3-(3-[2-aryl- 1-diazenyl]-1,3-diazepan-1-ylmethyl)-1,3-diazepan-1-yl] -1-diazenes (8), has been synthesized from the reaction of diazonium salts with a mixture of 1,4-diaminobutane and formaldehyde. All new compounds [...]

Abstract: Reaction of a series of diazonium salts with a mixture of formaldehyde and 1,2-diamino-2-methylpropane affords the 3-({5,5-dimethyl-3-[2-aryl-1-diazenyl]-1-imidazolidinyl}methyl)- 4,4-dimethyl-1-[2-aryl-1-diazenyl]imidazolidines (1a-1f) in excellent yield. The products have been characterized by IR [...]

A new series of bistriazenes has been synthesized from a general reaction of diazonium salts with a mixture of 1,3-diaminopentane (DYTEK® EP diamine) and formaldehyde, which affords the 4-ethyl-3-({6-ethyl-3-[2-aryl-1-diazenyl]hexahydro-1-pyrimidinyl} methyl)-1-[2-aryl-1-diazenyl]hexahydropyrimidines (1). Each of the molecules of type 1 is built up of two equivalent 3-(aryldiazenyl)-6-ethylhexahydro-1-pyrimidinyl groups attached to a central methylene group. The importance of this study is in part due to the fact that the formaldehyde-1,3-diaminopentane system has not previously been investigated. All new compounds have been characterized by IR and NMR spectroscopy, with elemental analysis for selected compounds; one example from the series has been unequivocally characterized by X-ray crystallography. Although analysis of the NMR spectra is made somewhat difficult because of broadness and coalescence of signals due to the rotational dynamics of the N--N single bonds, it is possible to fully assign the proton spectra of all compounds and to detect 94% of all carbon signals. The fine structure within the proton spectra illustrate the diastereotopic nature of the methylene group protons because of the presence of a stereocenter in each hexahydropyrimidine ring. The general conclusion of this study is that alkanediamines with three carbon atoms in the spacer link between the nitrogen atoms give rise to the linear bicyclic molecules of type 1, 2, and 3, in contrast to the case of ethylenediamine (spacer link has two carbon atoms), which affords molecules of type 7 that exemplify the bridged bicyclic bistriazene structure. The new compounds of series 1 represent an extension of a broad ranging study of the synthesis of new bistriazene derivatives of (1,x)-diazacycloalkanes. Key words: triazene, diazonium coupling, hexahydropyrimidine, diaminopentane, diazacycloalkanes, stereocenter, diastereotopic protons. On a effectue la synthese d'une nouvelle serie de bistriazenes par le biais d'une reaction generale des sels de diazonium avec un melange de 1,3-diaminopentane (DYTEK ® EP diamine) et de formaldehyde qui conduit a la formation de 4-ethyl-3-({6-ethyl-3-[2-aryldiazen-1-yl]hexahydropyrimidin-1-yl} methyl)-1-[2-aryldiazen-1-yl]hexahydropyrimidines (1). Chacune des molecules du type 1 correspond a l'addition de deux equivalents de groupes 3-(aryldiazenyl)6-ethylhexahydropyrimidin-1-yle a un groupe methylene central. L'importance de cette etude reside en partie dans le fait que le systeme formaldehyde-1,3-diaminopentane n'avait pas ete etudie anterieurement. Tous les nouveaux composes ont ete caracterises par spectroscopies IR et RMN et par analyse elementaire de composes choisis; un exemple de la serie a ete caracterise sans equivoque par diffraction des rayons X. Meme si l'analyse des spectres RMN est rendue assez difficile en raison de la largeur et de la coalescence des bandes provoquee par la dynamique rotationnelle des liaisons simples N--N, il a ete possible de faire une attribution complete des spectres du proton de tous les composes et de detecter 94 % des signaux dus au carbone. La structure fine observee dans les spectres du proton illustre la nature diastereotopique des protons du groupe methylene qui decoule de la presence d'un centre stereogene dans chacun des cycles hexahydropyrimidines. La conclusion generale de cette etude est que les alcanediamines comportant trois atomes de carbone comme lien qui separe les atomes d'azote conduisent a des molecules bicycliques lineaires des types 1, 2 ou 3, en opposition avec ce qui a ete observe dans le cas de l'ethylenediamine (lien comportant deux atomes de carbone) qui conduit a des molecules du type 7, un exemple de structure bistriazene bicyclique pontee. Les nouveaux composes de la serie 1 representent une extension d'une etude de grande envergure sur la synthese de nouveaux derives bistriazene des (1,x)-diazacycloalcanes. Mots cles : triazene, couplage de diazonium, hexahydropyrimidine, diaminopentane, diazacycloalcanes, centre stereogene, protons diastereotopiques., Introduction A triazene is any molecule containing three contiguous nitrogen atoms with one N=N double bond, i.e., N=N-N. Triazenes have been studied extensively as versatile tools for organic synthesis (1), [...]

Reaction of a series of diazonium salts with piperazine in a 2:1 molar ratio affores excellent yields of the 1,4-di-[2-aryl-l-diazenyl] piperazines (3), which have been characterized by IR and NMR spectroscopy. Structural characterization is supported by elemental analysis or by mass spectrometry with accurate mass measurement of the molecular ion. The protons of the piperazine ring hydrogens give rise to a sharp singlet at ca. 4 ppm in the NMR spectra, indicating that the conformational equilibrium in the piperazine ring is rapid on the NMR timescale. The four equivalent carbon atoms of the piperazine ring resonate in the range 46-48 ppm. A variable temperature NMR experiment suggests that there is restricted rotation around the N2--N3 bond of the triazene moiety in 3. The NMR data compares favorably with previous reported data for 1-aryldiazenyl-4-methylpiperazines (1) and 1,4-di-(2-aryldiazen-l-yl)homopiperazines (2b). Key words: triazene, piperazine, diazonium coupling, NMR. Resume : La redaction d'une serie de sels de diazonium avec de la piperazine dans un rapport molaire de 2 : 1 conduit, avec d'excellents rendements, a des 1,4-di-[2-aryldiazen-l-yl]pipeprazines (3) qui ont ete caracterisees par les spectres IR et RMN. Les caracterisations des structures sont supportees par des analyses elementaires ou par spectromedrie de masse avec des mesures precises de la masse de l'ion moleculaire. Dans le spectre RMN, les protons du noyau piperazine se presentent sous la forme d'un singulet effile a environ 4 ppm, ce qui suggere que l'equilibre conformationnel du cycle piperazine est rapide par rapport a l'echelle de temps de la RMN. La resonance des quatre atomes de carbone equivalents du noyau de la piperazine se situe entre 4e et 48 ppm. Une experience de RMN a temperature variable suggere l'existence d'une rotation empechee autour de la liaison N2--N3 de la portion triazene du compose 3. Les donnees de la RMN se comparent avantageusement avec celles rapportees anterieurement pour les 1-aryldiazenyl-4-methylpiperazines (1) et 1,4-di-(2-aryldiazen-l-yl) homopiperazines (2b). Mots cles : triazene, piperazine, couplage de diazonium, RMN. [Traduit par la Redaction]

Aim: Geographic range size varies greatly across species. Climate, along with aspects of a species' biology, may influence its spatial extent. We investigate intrinsic and extrinsic predictors of range size in Australian skinks. We predicted that larger body size, longer limbs, and larger clutch sizes would be associated with larger ranges, and that ranges would be larger in colder, more arid, and more seasonal climates. Location: Mainland Australia. Taxon: Skinks (Scincidae). Methods: We test for climatic and geographic correlates of range size of Australian skink species (417 of 462 described species), as well as investigate the effects of body size and clutch size (259 species). We compare detailed morphological measurements of 1,324 specimens across nine pairs of widespread and narrow‐ranged congeneric species to investigate the roles of intrinsic (body size, clutch size, morphology) and extrinsic (mean temperature and precipitation) factors in determining range size. Results: In the broader analysis, large range sizes were associated with the presence of fully developed limbs, low precipitation seasonality, high temperatures, and high precipitation. Ranges of species traversing the Great Dividing Range are larger by an order of magnitude than those east of the range, with western ranges being intermediate. Affinity to specific biomes explained less variation than climatic variables. For the nine species pairs, wide‐ranging species share similar morphologies and clutch sizes with overlapping narrow‐ranging congeners, but generally inhabit more arid regions. Main conclusions: We found several extrinsic, but few intrinsic, factors were correlated with range size. The narrow mesic belts in Australia compared with the extensive expanse of arid and semi‐arid regions may explain why desert species have larger ranges. This interpretation agrees with the notion that the size of the domain, here a climatic domain rather than a physical one, may exert strong influence on species' range sizes. [ABSTRACT FROM AUTHOR]

Australia is in the midst of an extinction crisis, having already lost 10% of terrestrial mammal fauna since European settlement and with hundreds of other species at high risk of extinction. The decline of the nation's biota is a result of an array of threatening processes; however, a comprehensive taxon‐specific understanding of threats and their relative impacts remains undocumented nationally. Using expert consultation, we compile the first complete, validated, and consistent taxon‐specific threat and impact dataset for all nationally listed threatened taxa in Australia. We confined our analysis to 1,795 terrestrial and aquatic taxa listed as threatened (Vulnerable, Endangered, or Critically Endangered) under Australian Commonwealth law. We engaged taxonomic experts to generate taxon‐specific threat and threat impact information to consistently apply the IUCN Threat Classification Scheme and Threat Impact Scoring System, as well as eight broad‐level threats and 51 subcategory threats, for all 1,795 threatened terrestrial and aquatic threatened taxa. This compilation produced 4,877 unique taxon–threat–impact combinations with the most frequently listed threats being Habitat loss, fragmentation, and degradation (n = 1,210 taxa), and Invasive species and disease (n = 966 taxa). Yet when only high‐impact threats or medium‐impact threats are considered, Invasive species and disease become the most prevalent threats. This dataset provides critical information for conservation action planning, national legislation and policy, and prioritizing investments in threatened species management and recovery. [ABSTRACT FROM AUTHOR]