Multivariate Discriminant Function Analysis Research Articles

The latest steps of human evolution: What the hard evidence has to say about it?

The latest periods of human evolution are a heated topic of debate and have been at the center of paleoanthropological discussions since the beginning of the field. In the last twenty years, new excavations increased the geographic range of paleoanthropological data, new fossil hominins of the last third of the Pleistocene were found, and old key fossils were redated by modern and more accurate methods. The new picture emerging from this research changed the discussion about the neandertal-sapiens interaction, the finding of their common ancestor, and the understanding of how our lineage evolved. To integrate these new discoveries and to better contextualize how they fit in the hominin framework of the Chibanian, we compared the cranial morphology of 86 well-preserved fossils from Europe, Africa, and Asia of the last 500 thousand years. 25 linear measurements were used to describe the cranial morphology of the fossils, and their biological affinities were explored though multivariate discriminant function analyses. These analyses allow us to assess affinities and possible phylogenetic relationships of Archaic Homo species, including the expressive morphological variability of the specimens included under the umbrella-term “Homo heidelbergensis” from Africa, Asia, and Europe. Our results support that cannot be accommodated in one same species. Additionally, we contribute to the disputable discussion about the origin of H. sapiens, adding support to an African origin for our species.

Evaluating the patella bone for sex estimation in Northwest Indian subjects: A radiological study

ObjectivesIn forensic identification, pelvis, post cranial bones especially long bones and skull are considered best for sex estimation. But there are circumstances where these bones cannot be recovered for establishing the correct biological profile of unknown human skeletal remains. In those cases, other skeletal bones should be investigated for sex estimation. The goal of the present study was to validate whether the patellar bone measurements through CT scan can be used for the sex estimation in Northwest Indian subjects. Materials and methodsThis study comprises of 344 subjects (179 males and 165 females) between the age group of 18- 80 years. Eight variables of patella were selected in the study for sex estimation using CT scan images of patella. ResultsAll the variables were statistically significant with p-value< 0.05 for indicating the sex. Univariate and multivariate discriminant function analysis (direct and stepwise method) were applied for sex estimation. The overall accuracy rate of classifying sex was 88.4% for multivariate stepwise discriminant function analysis and 87.8% for multivariate direct discriminant function analysis. Total perimeter of patella (TPP) was found to be the best variable for sex estimation with overall accuracy rate of 84.9%. ConclusionThe present study emphasized on the most dimorphic variables of patella in Northwest Indian subjects. New variables of patella namely Patellar Femoral Distance (PFD), Patellar Apex Angle (PAA), Frontal Surface Area of patella (FSA) and Total Perimeter of Patella (TPP) were added in the study of Indian subjects. This brought an overall accuracy rate of classification above 85%. The study confirmed that patellar bone's linear and angular measurements can be used for forensic identification casework.

Cranio-facial bones evaluation based on clinical CT data for sex determination in Northwest Indian population

The skull and pelvis have been the first choice of bones for determination of unknown human remains. The goal of the present study was to derive discriminant function equations by using clinical CT scan data of cranio-facial bones for sex determination in Northwest Indian population. This study was conducted at Department of Radiology, by collecting the retrospective data of CT scan of 217 samples. In the data, 106 were males and 111 were females in the age group between 20 and 80 years. The total number of parameters under investigation were 10. All the selected variables were sexually dimorphic and showed significant values. 91.7% of original grouped cases were correctly classified to their sex category. The TEM, rTEM and R were under the acceptable limits. The univariate, multivariate and stepwise discriminant function analysis recorded an accuracy of 88.9%, 91.7% and 93.6% respectively. Multivariate direct discriminant function analysis stepwise method yielded the highest level of accuracy in differentiating males and females. All the variables reflected statistically significant difference between males and females (p less than 0.001). The best single parameter with highest level of sexual dimorphic trait was length of cranial base. This study aims to provide sex assessment using clinical data of CT scan in Northwest Indian population by incorporating the BIOFB cranio-facial parameter. The morphometric measurements taken on CT scan images can be utilized by forensic experts in identification process.

Characterization of Echolocation Calls from Insectivorous Bats in Puting Bato Cave 5, Burdeos, Polillo Island, Philippines

Acoustic recording is rarely applied in studying Philippine bats, which is reflected by the scarcity of related publications in the country. As a result, the echolocation calls of many local bat species are still unknown, and a reliable bat call library does not exist. Here, we described the echolocation call of some insectivorous bats in Polillo Island and used the call characteristics to define each species. We captured and recorded the echolocation calls of cave-dwelling bats in Puting Bato Cave 5 in October and November 2019. Using BatSound, we measured the spectral and temporal call characteristics and determined the call structure and duty cycle of all recorded individuals. Then, we applied multivariate discriminant function analysis (DFA) to classify the calls into species and identify the call parameter with the highest discriminating power. In total, we recorded 104 individual bats from five species belonging to four families. All species from families Miniopteridae and Vespertilionidae produced steep frequency-modulated (FM) sweeps, while the species belonging to families Hipposideridae and Rhinolophidae emitted calls with constant frequency and FM components. Among the recorded species, Hipposideros coronatus had the highest peak frequency record (&gt; 150 kHz), while Myotis macrotarsus had the lowest (&lt; 40 kHz). Meanwhile, the longest call duration was recorded from Rhinolophus arcuatus (&gt; 40 ms), while Miniopterus paululus produced the shortest call (&lt; 3 ms). The DFA perfectly classified the calls into the correct species and peak frequency was the most important predictor among the call parameters measured. Our results provide strong evidence that insectivorous bats in Puting Bato Cave 5 produce species-specific echolocation calls, and acoustic recording can be a reliable method to enhance research on these cave-dwelling bats

Assessing the Validity of Mojave Desert Lake Mohave and Silver Lake Projectile-Point Types

ABSTRACT This study uses univariate and multivariate statistical analyses to assess whether Lake Mohave and Silver Lake projectile points from the Mojave Desert of western North America are statistically discrete, recognizable, and valid types. Univariate analyses run on 400 Lake Mohave and Silver Lake points reveal significant differences in six linear and three angle measures, though overlapping measurements pose difficulties for differentiating the types. To address the problem of overlapping measurements, multivariate principal components and discriminant function analyses were employed to statistically define groups of related attributes. Size- and shape-based attributes of the stem distinguish approximately 80% of the sample to type and reveal region-wide consistency among archaeologists who have classified these points to type. Though this study did not entirely overcome the challenge of using metrics to differentiate Lake Mohave from Silver Lake points, key discriminating variables are now better defined and the types deemed valid.

Sex estimation in a Turkish population using Purkait’s triangle: a virtual approach by 3-dimensional computed tomography (3D-CT)

Sex estimation is considered one of the first steps in the forensic identification process. Morphological and morphometrical differences between males and females have been used as means for morphoscopic and metric methods on both cranial and postcranial skeletal elements. When dry skeletal elements are not available, virtual data can be used as a substitute. The present research explores 3-dimensional (3D) scans from a Turkish population to test a sex estimation method developed by Purkait (2005). Overall, 296 individuals were used in this study (158 males and 138 females). Purkait’s triangle parameters were measured on computed tomography (CT) scans obtained from both right and left femora of each patient at the Bakirkoy Dr. Sadi Konuk Training Research Hospital (Istanbul, Turkey). Intra- and inter-observer errors were assessed for all variables through technical error of measurements analysis. Bilateral asymmetry and sex differences were evaluated using parametric and non-parametric statistical approaches. Univariate and multivariate discriminant function analyses were then conducted. Observer errors demonstrated an overall agreement within and between experts, as indicated by technical error of measurement (TEM) results. No bilateral asymmetries were reported, and all parameters demonstrated a statistically significant difference between males and females. Fourteen discriminant models were generated by applying single and combined parameters, producing a total correct sex classification ranging from 78.4% to 92.6%. In addition, over 67% of the total sample was accurately classified, with 95% or greater posterior probabilities. Our study demonstrates the feasibility of 3D sex estimation using Purkait’s triangle on a Turkish population, with accuracy rates comparable to those reported in other populations. This is the first attempt to apply this method on virtual data and although further validation and standardisation are recommended for its application on dry bone, this research constitutes a significant contribution to the development of population-specific standards when only virtual data are available. Key points CT analysis using Purkait’s triangle is a suitable tool for assessment of sex in unidentified individuals. The best overall estimation rate was achieved with the F11 model, with around 92% of accuracy. The results suggested 78.4% to 92.6% correct sex identification rates. More research is needed to expand the sample set and verify the results.

Identification of sex using discriminant function analysis of fingerprint ridge density at three topological areas among North Indian population

The present study attempted to identify sex of an individual using a fingerprint ridge density at three topological areas in the North Indian population. The study population consisted of 134 males and 136 females aged 17 to 25 years (mean age 19.34±2.12). Ridge density (RD) at radial, ulnar and proximal topological areas of the distal phalanges were determined on the surface area of 25mm2. Fingerprint ridge density in a defined area was significantly higher among females as compared to their male counterparts at radial, ulnar and proximal topological areas for both hands. Sexual dimorphic ratio also supported this trend for all three counting areas in right and left hands. Univariate discriminant function analysis explained that the left 2 radial (L2R) (88.1%) had the highest percentage of accuracy for sex identification, followed by the left 3 ulnar (L3U) (82.1%) and the right 2 ulnar (R2U) (81.6%). Multivariate discriminant function analysis showed that the radial topological area of the left hand was the best predictor of sex with the overall accuracy of 84.4%with following discriminant function equation −8.263 − 0.236(L1R) + + 0.321(L2R) + 0.269(L3R) + 0.268(L4R) − 0.067(L5R).&#x0D; It can be inferred that ridge density in the radial topological area of left hand is the most reliable tool for identifying the sex of an individual.

Anthropometric characteristics of patella for sex estimation using magnetic resonance images

• The sexual diagnostic accuracy of patella for transverse, craniocaudal and antro-posterior lenght were 84.5%, 75.2% and 65.8% respectively. • The maximum transvers and craniocaudal lenghts were selected in the stepwise with an average accuracy of 85.7% in correct sex clasification. • Measuring the patella dimensions by the MRI method can be effective for sex estimation with good accuracy in the Iranian population. Sex estimation of skeletal remains is an essential step in forensic anthropology since. In this study, sex estimation with patella metric parameters obtained from Magnetic resonance imaging ( MRI ) of an Iranian population, which consists of 161 living subjects (79 males, 82 female) aged between 30 – 50 years, is performed. Univariate discriminant analysis and multivariate discriminant function analysis are used for three measurements on the patella (transverse length, craniocaudal length, and anterioposterior length) in this study. The diagnostic accuracy of patella sex estimation for transverse, craniocaudal and Anterior-posterior lengths were %84.5, %75.2 and %65.8, respectively. In the discriminant analysis, the maximum transverse length and maximum craniocaudal length were selected in the stepwise analysis with an average accuracy of 85.7% in correct sex classification. In conclusion, measuring the patella dimensions by the MRI method can be effective for Sex estimation with good accuracy in the Iranian population.

Sex estimation in a modern Turkish population using the clavicle: a computed tomography study

ABSTRACT Morphometric analysis of the clavicle is a potential source of useful data for the estimation of sex. Clavicle is often retrieved intact from decomposed and scavenged remains when pelvis and skull, essential sex indicators, are often found damaged or missing. The objective of this study is to analyse clavicle morphometric data for sex estimation in a Turkish population. Computed tomography (CT) scans of the thorax of two hundred Turkish adult patients (71 male and 81 female patients with an age range of 22–80 years) were included. Furthermore, morphometric data for the left clavicle using two-dimensional (2D) and three-dimensional (3D) clavicle CT images were obtained, and six variables were measured in the clavicle images. Univariate and multivariate discriminant function analysis (DFA) was used to create population-specific functions for sex estimation. The classification accuracy for the cross-validated data ranged from 75% to 89% in the uni- and multivariate DFA. Stepwise discrimination analysis yielded an 89% accuracy rate for the maximum length and midshaft circumference variables. The study showed that the clavicle can provide useful data for estimating sex in a modern Turkish population and that when there is difficulty accessing bone collections, CT scans can provide useful data for sex estimation.

SEX DETERMINATION FROM DISCRIMINANT FUNCTION ANALYSIS OF CEPHALOMETRIC MEASUREMENTS OF BROKPAS AND PURIGPAS OF LADAKH (UT): A FORENSIC ANTHROPOLOGICAL STUDY

Forensic anthropology involves diverse applications of anthropological knowledge to medico-legal problems like human identification based on sex determination, age estimation, stature reconstruction and deciphering ancestry of unknown living individuals or skeletal remains. Sex can be determined by using different body parts such as extremities (legs and arms) parameters, head, face, clavicle, and others parameters. In present cross-sectional study, cephalometric dimensions of 800 Ladakhi subjects (431 males and 369 females) of Purigpas and Brokpas ancestry were taken. Descriptive statistics of cumulative cephalometrics in two sexes revealed that all the measurements were significantly larger in males than the females (p<0.001). Statistically significant sex differences were found in the various anthropometric, cephalometric and morphological features of Brokpas and Purigpas of Kargil (Ladakh, UT). Univariate discriminant function analysis found head length as the best cephalofacial variable to estimate sex of 73.4% individuals; followed by physiognomic facial length to estimate sex of 71% subjects. From multivariate discriminant function analysis, the physiological facial length, head length, nasal breadth, head circumference, nasal height, bizygomatic breadth, length of right ear and left ear breadth were selected as the best variables to correctly classify sex of 83.8% individuals to their category (81.9% males and 85.9% females). The present study results are the only cephalometric standards which have been suggested for Purigpas and Brokpas of Ladakh (Jammu and Kashmir) which can be used for medico-legal sex determination of unknown individuals of studied population.

Sex estimation from upper limb bones in a Thai population.

Sex estimation from skeletal remains is an important practice for forensic human identification. The aims of this study were to assess sexual dimorphism and to develop discriminant function equations for sex estimation using 12 measurements of upper limb bones (humerus, ulna, and radius) in a Thai population. The sample consisted of 228 Thai skeletons (114 males and 114 females) from the Forensic Osteology Research Center, Chiang Mai University, Chiang Mai, Thailand. All skeletal length variables were measured according to the Standards for Data Collection from Human Skeletal Remains. The values of measurements were used to develop the sex estimation equations using univariate and multivariate discriminant function analyses. The results of sexual dimorphism showed that upper limb bone lengths of males were statistically significantly longer than those of females in all dimensions (P<0.05). For univariate discriminant function analysis, the results showed that the epicondylar breadth of the humerus, the physiological length of the ulna, and the antero-posterior diameter at the midshaft of the radius were the best indicators for sex estimation in the humerus, ulna, and radius, respectively. Moreover, the multivariate discriminant function equation using all variables of the ulna and radius was the best indicator for sex estimation. In conclusion, the discriminant function equations derived from upper limb bone measurements provided highly accurate sex estimation in Thai samples. Therefore, these equations using humerus, radius, and ulna measurements can be applied for sex estimation with good accuracy in Thais.

Assessing zygomatic shape and size for estimating sex and ancestry in a South African sample

Unidentified, decomposed and skeletonised human remains are frequently found in South Africa, therefore, standardised, reliable and relevant sex and ancestry estimation methods are required for forensic identification. This study assessed sex and ancestral variation in zygomatic size and shape in a South African population using geometric morphometric analyses. The zygoma of 158 South African individuals were sampled. Eight zygomatic landmarks were captured in 3-dimensions using a Microscribe G2 digitiser and assessed using procrustean geometric morphometrics. Shape and size differences were analysed using multivariate linear regression, discriminant function and canonical variate analyses. Males had significantly larger zygomas than females. Significant shape variation was found between ancestral groups. Bantu-speaking and Mixed ancestry individuals had narrower, shorter and more anteriorly projecting orbital margins, whilst Europeans had vertically elongated and receded orbital margins. European ancestral groups were most discernible from Bantu-speakers and Mixed ancestral groups. Ancestry estimation accuracies improved when ancestry was aggregated with sex. Pairwise ancestry-linked comparisons in females were as follows; Bantu-speakers (76%) from Europeans (72%), Bantu-speakers (71%) from Mixed ancestry (59%) and European (72%) from Mixed ancestry (63%). Similarly, ancestry-linked comparisons in males were as follows; Bantu-speakers (77%) from Europeans (81%), Bantu-speakers (53%) from Mixed ancestry (59%) and European (72%) from Mixed ancestry (82%). Size differences are putatively linked to variations in hormone-regulated growth and muscular robusticity between males and females. Shape variations between ancestral groups are likely attributable to the heterogenous genetic and ancestral origins of the South African population. It is challenging to distinguish between South Africa Bantu speakers and Mixed ancestry people due to Mixed ancestry individuals having variable genetic contributions from Khoesan, Bantu-speakers, Europeans and Asians. Bantu-speaking and Mixed ancestry people had zygomatic morphologies consistent with historical thermoregulatory adaptations to sub-Saharan climates, reported in African-descendants. Zygomatic morphology in European descendants suggests ancestral origins from colder climatic regions. This study demonstrated the utility of the zygoma in distinguishing between ancestral groups in South Africa, but further research is required to develop population-specific standards to distinguish between South African populations with shared African ancestry. The zygoma shows a promising ability to estimate sex and ancestry in South Africans, suggesting population specific standards for this bone may be of forensic interest.

Forensic odontological sex determination of Ajnala skeletal remains based on the statistical equations generated from the odontometrics of known teeth

Anthropological techniques are evolving and expanding continuously to decode and interpret the hidden information embedded within human skeletal and dental remains as biological language. Various studies have been reported for sex estimation from odontometric features of the teeth found in forensic or bio-archaeological contexts. Though the accuracy levels of such methods is just close to forensic thresholds, they serve as significant adjuncts to identity assessments from other methods. Thousands of bones and teeth were excavated from a disused well found situated underneath a religious structure at Ajnala (Amritsar, India) in April 2014. In the present study, the sex of unknown molar teeth retrieved from Ajnala skeletal assemblage was estimated using the customized discriminant and logistic regression formulas generated from the odontometrics of known teeth collected from Northwest Indian subjects. Five hundred and eleven mandibular molars (254 modern and 257 Ajnala human teeth) were measured for eight buccolingual and mesiodistal diameters at different levels. The multivariate discriminant and logistic regression equations were developed from odontometrics of known teeth to classify 75.4% and 76.1% teeth to their sex category, respectively. These equations were applied to odontometrics of Ajnala teeth and their D-estimates were calculated. It was found that 83% and 96% Ajnala teeth were identified to be of males from the multivariate logistic regression and discriminant function analysis, respectively. It corroborated the written versions about the Ajnala skeletal remains belonged to male soldiers killed in 1857 by the colonial rulers.

Sex estimation by Mastoid Triangle using 3D models.

Mastoid Triangle (MT) is a triangle constructed between the landmarks porion, mastoidale and asterion. The aim of the study is to evaluate the sex differences in the MT size in Bulgarian adults and to develop discriminant functions for sex estimation based on the MT sides and area. The study was carried out on 148 head CT scans. A sample of 53 males and 53 females was used for development of discriminant functions, and a test sample of 21 males and 21 females was applied for their validation. Using the software InVesalius©, 3D models of the skulls were segmented and exported in STL format. The 3D coordinates of the landmarks porion, asterion and mastoidale were collected using the software MeshLab©. The MT sides, area and angles were calculated. The sex differences were assessed by the independent t-test. Bilateral differences were evaluated using the paired t-test. Univariate and multivariate discriminant function analyses were applied. The results showed that the MT sides and area differed significantly between both sexes. Sex differences were also established for the angle at mastoidale. Bilateral differences were found in males for the distance porion-mastoidale, which was significantly greater on the right side. The MT dimensions showed sufficient discriminating power for sex estimation among Bulgarians (up to 89%), and the total MT area proved to be the best single sex discriminating trait. The test sample corroborated the usefulness of the MT in sex estimation demonstrating similar or higher overall accuracy rates.

Assessing sediment yield and sources using fingerprinting method in a representative catchment of the Loess Plateau, China

Quantitative assessment of sediment yield and sources is of great importance for future soil and water conservation and watershed management in erosion-prone areas. This study investigated sediment yield and sources by using a simple fingerprinting method in a dam-controlled watershed on the northern Loess Plateau. The sampling sediment profile exhibited 24 flood couplets corresponding to rainfall storms from 2001 to 2014. A total of 2.05 × 105 t sediment was trapped during the period. The annual sediment yield varied from 0 to 430 t ha−1 year−1, with an average annual sediment yield of 146.1 t ha−1 year−1. Ten sediment properties (i.e., σ13C, σ15N, TOC, TN, C/N, Xlf, Xhf, Xfd, 137Cs, 210Pb) were potentially selected to identify the sediment sources. The multivariate discriminant function analysis (DFA) test suggested that three soil properties (Χhf, TN, and 137Cs) comprised the optimum composite fingerprinting. The results demonstrated that sandstone contributed nearly 90% of sediment in 2012 and 56.1% in 2003. The contribution from arable land varied from 5.2% in 2005 to 44.6% within the period of 2013–2014. On average, approximately 74.06% of sediment originated from the weathered sandstone, followed by 15.67% from arable land, and the remaining 10.27% from uncultivated land. Our finding indicated that bare sandstone was the main sediment source, leading to relatively high sediment yield in the study area. This study provides a method with great potential for sediment yields assessment and sediment source identification in ungauged watersheds on the Loess Plateau.

Variation in Agro-morphological Traits of Some Turkish Local Pop, Flint and Dent Maize (Zea mays L.)

Turkish maize accessions collected from north of Turkey were investigated for agro-morphologic variation in three maize kernel types (flint, pop and dent) including 79 accessions. Eight agronomic and morphologic traits (ear length, ear kernel row number, ear height, leaf number, 1000 kernel weight, tassel length, leaf width and leaf length) were analysed by ANOVA and principal component analysis. Varieties and accessions were found significantly different for variance components which were made up high variance due to accessions. Positive correlations were found between agronomic and morphologic traits. Multivariate discriminant function analysis with eight traits revealed that first two of multivariate correlation covered 86.6%, and next 69% of total variation among accessions and the first multivariate discriminant function had high eigenvalue with 76.8% of total variance between varieties belonged to flint and pop maize accessions while the second multivariate variable belonged to flint and dent maize accessions. These multivariate variables correctly classify three maize varieties maintaining maize accessions for their various characteristics with agronomic and morphological traits.

Morphometric and Meristic Characterization of Common Carp, Cyprinus Carpio Strains Sourced from Jos, Bauchi and Ibadan, Nigeria

The study investigated the morphometric and meristic characterization of Common carp (Cyprinus carpio) sourced from Jos Bauchi and Ibadan (Nigeria). In comparing the morphometric and meristic characters one hundred and eighty (180) adult Common carp, Cyprinus carpio were used. Twenty four (24) morphometric and six (6) meristic characters were studied. Measurements of the morphometric features were taken to the nearest centimeter by means of a measuring board, measuring rule, pair of dividers for the length, while the weight was taken by means of a weighing scale (salter scale) to the nearest gram. ANOVA, multivariate technique principal component analysis (PCA) and discriminant function analysis were also applied to the transformed morphometric data to; classify the fish into one or several mutually exclusive groups. The Morphometric study indicated that seven parameters did not differ significantly (p&gt;0.05) between Jos (male and female), and Bauchi (male and Female) strains. The parameters are the body depth, caudal fin length, pectoral fin height, standard weight, pre dorsal distance, eye diameter and body weight. In the meristic count, only the dorsal fin spine did not differ significantly (p &gt;0.05) among the Jos, Bauchi, and Ibadan strains in all sexes. The study revealed that there was a genetic distance between male and female Carp sourced from Ibadan and that of Jos and Bauchi, where as male and female Carp from Jos and Bauchi showed genetic closeness.

The effect of climate on Burgundy vintage quality rankings

Aim: Based on consensus rankings from prominent rating authorities, we examined the importance of a suite of climatic variables, organized by winegrape phenological stage, in distinguishing between high- and low-ranked vintages in Burgundy.Methods and Results: Vintage ratings of Burgundy wines acquired from 12 sources were evaluated to develop consensus rankings for red and white wines from 1961–2015. Climate variables (air temperature, precipitation, degree-day accumulations, etc.) were organized by mean phenological stage and compared between good and poor vintages using Mann-Whitney U tests and multivariate stepwise discriminant function analysis. High temperatures, particularly during the growing season, were found to be the most consistently important climatic factor in distinguishing good-quality vintages from poor-quality vintages. The best red vintages had a greater diurnal temperature range during the growing season, whereas the top white vintages were not distinguished by unusually warm conditions, but the bottom-ranked white vintages were particularly cool and wet. The impact of rainfall varied across the growing season, with top-ranked Burgundy wines benefitting from rainfall during the bud break period and dry conditions during the ripening phase.Conclusions: The most important climatic factor in distinguishing between top- and bottom-ranked vintages is growing season temperature, especially high diurnal temperature range (for reds) and high average maximum temperatures (for whites). Good Burgundy vintages are more likely when there is ample rainfall during the bud break period in April and dry conditions during the véraison and ripening phases.Significance and Impact of the Study: As viticulturalists adapt to regional climate trends, a better understanding of how specific climate variables affect wine quality becomes increasingly important in viticulture management.

Seasonal microclimatic variation in a succession gradient of low thorn forest in Northeastern Mexico

Global increase in land cover change and deforestation bring about fragmentation of a high proportion of native vegetation areas. Microclimate is among the first modified factors after vegetation loss, effects of such disturbances are critical for species performance. However, both secondary succession and seasonality provoke further modifications in abiotic environment after disturbances. Although microclimate patterns during succession are well studied for several ecosystems, they are practically unknown for low thorn forests. In Northern Mexico, this is an endangered ecosystem characterized by harboring a high percentage of endemics. Measurement of microclimatic factors is crucial for understanding possible consequences of post-disturbance time on species inhabiting this ecosystem. This work aimed to assess seasonal variation of microclimatic patterns in a succession gradient of four categories (conserved areas, 31, 17 and four years of succession). The study area was delimited using Landsat satellite images (1973, 1986, 2000, 2005, and 2013) in a fragment of low thorn forest in Northeastern Mexico. For microclimate characterization we studied wind speed, temperature, relative humidity, heat index, dew point, and evapotranspiration. Variables were measured monthly on eight plots, in each of the four successional categories, during two different seasons: wet (May through October 2016) and dry season (November 2016 through April 2017). A multivariate discriminant function analysis showed that microclimate differs among successional stages. In the wet season, early succession areas were characterized by higher values of heat index and wind speed, contrary to conserved areas. In the dry season, successional differences were attributed to wind speed and relative humidity. Moreover, microclimate differences between categories and importance of variables measured were both higher only during the dry season. Our results show that seasonality influences greatly microclimatic patterns during secondary succession. In addition, each one of the successional categories exhibited unique microclimatic conditions. Remarkably, four, 17, and even 31 years succession categories differed from conserved areas. This work provides evidence on the great relevance of seasonality and microclimate for studying secondary succession. It is suggested to take both factors into consideration when implementing conservation programs concerning endangered habitats such as low thorn forests. As an ecosystem poorly studied, microclimate characterization provided herein, shall help to a better understanding and management of these areas.

Revision of the taxonomic status of Rhodanthidium sticticum ordonezi (Dusmet, 1915), an anthidiine bee endemic to Morocco (Apoidea: Anthidiini)

Rhodanthidium ordonezi (Dusmet, 1815) is recognized here as a valid species endemic to central and southern Morocco. It has previously been regarded as a subspecies of R. sticticum (Fabricius). The two taxa are in allopatry throughout most of their respective ranges, but probably cooccur in the Middle Atlas Mountains. They are clearly distinguished by their coloration and some aspects of their color patterns. Structural differences are minor, but a multivariate discriminant function analysis of 11 morphometric traits has showed that these are sufficient to assign 82.7% of all specimens correctly. While R. ordonezi has a restricted range in central and southern Morocco (extending over approximately 500 km), R. sticticum is widely distributed in the Mediterranean basin with a range extending over approximately 2500 km from east to west. The distribution areas of these two species are contiguous in the same ecozone of the Middle Atlas mountain range, but sympatric occurrence or a transition zone where intermediate specimens occur is not known.