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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.

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.

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 [...]

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]

Abstract Background Climatic oscillations throughout the Quaternary had profound effects on temperate biodiversity, but the extent of Quaternary climate change was more severe in temperate regions of the northern hemisphere than in the southern hemisphere. We sought to determine whether this geographic disparity differentially influenced the timing of intraspecific diversification events within ectothermic and endothermic vertebrate species. Using published phylogenetic hypotheses, we gathered data on the oldest intraspecific diversification event within mammal, bird, freshwater fish, amphibian, and reptile species from temperate-zone areas. We then tested whether the timing of diversification events differed between hemispheres. Results Our analyses provide strong evidence that vertebrates from temperate regions of the northern hemisphere are younger than those from the southern hemisphere. However, we find little evidence to suggest that this relationship differs between endotherms versus ectotherms, or that it varies widely across the five classes of vertebrates that we considered. In addition, we find that on average, endothermic species are much younger than ectothermic species. Conclusion Our findings suggest that geographic variation in the magnitude of climatic oscillations during the Quaternary led to substantial disparity in the timing of intraspecific diversification events between northern and southern hemisphere vertebrates, and that the magnitude of this divergence is largely congruent across vertebrate taxa.

Aim: Light Detection And Ranging (LiDAR) is a promising remote sensing technique for ecological applications because it can quantify vegetation structure at high resolution over broad spatial extents. Using country‐wide airborne laser scanning (ALS) data, we test to what extent fine‐scale LiDAR metrics capturing low vegetation, medium‐to‐high vegetation and landscape‐scale habitat structures can explain the habitat preferences of threatened butterflies at a national extent. Location: The Netherlands. Methods: We applied a machine‐learning (random forest) algorithm to build species distribution models (SDMs) for grassland and woodland butterflies in wet and dry habitats using various LiDAR metrics and butterfly presence–absence data collected by a national butterfly monitoring scheme. The LiDAR metrics captured vertical vegetation complexity (e.g., height and vegetation density of different strata) and horizontal heterogeneity (e.g., vegetation roughness, microtopography, vegetation openness and woodland edge extent). We assessed the relative variable importance and interpreted response curves of each LiDAR metric for explaining butterfly occurrences. Results: All SDMs showed a good to excellent fit, with woodland butterfly SDMs performing slightly better than those of grassland butterflies. Grassland butterfly occurrences were best explained by landscape‐scale habitat structures (e.g., open patches, microtopography) and vegetation height. Woodland butterfly occurrences were mainly determined by vegetation density of medium‐to‐high vegetation, open patches and woodland edge extent. The importance of metrics generally differed between wet and dry habitats for both grassland and woodland species. Main conclusions: Vertical variability and horizontal heterogeneity of vegetation structure are key determinants of butterfly species distributions, even in low‐stature habitats such as grasslands, dunes and heathlands. The information content of low vegetation LiDAR metrics could further be improved with country‐wide leaf‐on ALS data or surveys from drones and terrestrial laser scanners at specific sites. LiDAR thus offers great potential for predictive habitat distribution modelling and other studies on ecological niches and invertebrate–habitat relationships. [ABSTRACT FROM AUTHOR]

Joint species distribution models (JSDMs) simultaneously model the distributions of multiple species, while accounting for residual co‐occurrence patterns. Despite increasing adoption of JSDMs in the literature, the question of how to define and evaluate JSDM predictions has only begun to be explored.We define four different JSDM prediction types that correspond to different aspects of species distribution and community assemblage processes. Marginal predictions are environment‐only predictions akin to predictions from single‐species models; joint predictions simultaneously predict entire community assemblages; and conditional marginal and conditional joint predictions are made at the species or assemblage level, conditional on the known occurrence state of one or more species at a site. We define five different classes of metrics that can be used to evaluate these types of predictions: threshold‐dependent, threshold‐independent, community dissimilarity, species richness and likelihood metrics.We illustrate different prediction types and evaluation metrics using a case study in which we fit a JSDM to a frog occurrence dataset collected in Melbourne, Australia.Joint species distribution models present opportunities to investigate the facets of species distribution and community assemblage processes that are not possible to explore with single‐species models. We show that there are a variety of different metrics available to evaluate JSDM predictions, and that choice of prediction type and evaluation metric should closely match the questions being investigated. [ABSTRACT FROM AUTHOR]