Aerial Samples Research Articles

Tracking arbuscular mycorrhizal fungi to their source: active inoculation and passive dispersal differentially affect community assembly in urban soils.

Communities of arbuscular mycorrhizal (AM) fungi assemble passively over time via biotic and abiotic mechanisms. In degraded soils, AM fungal communities can assemble actively when humans manage mycorrhizas for ecosystem restoration. We investigated mechanisms of urban AM fungal community assembly in a 2-yr green roof experiment. We compared AM fungal communities in inoculated and uninoculated trays to samples from two potential sources: the inoculum and air. Active inoculation stimulated more distinct and diverse AM fungal communities, an effect that intensified over time. In the treatment trays, 45% of AM fungal taxa were detected in the inoculum, 2% were detected in aerial samples, 23% were detected in both inoculum and air, and 30% were not detected in either source. Passive dispersal of AM fungi likely resulted in the successful establishment of a small number of species, but active inoculation with native AM fungal species resulted in an immediate shift to a diverse and unique fungal community. When urban soils are constructed or modified by human activity, this is an opportunity for intervention with AM fungi that will persist and add diversity to that system.

Different VOC species derived from fugitive emissions at various altitudes around petrochemical plant

Volatile organic compounds (VOCs) emitted from fugitive sources are crucial for environmental and health risk assessments. However, monitoring these emissions at ground level, according to traditional technical specifications, has made it challenging to identify polluted air masses and collect purposeful samples. In this study, we focused on utilizing an unmanned aerial vehicle system to obtain air samples around a petrochemical industrial park. We conducted a quantitative analysis of 108 VOC species and compared the results between aerial and ground-level samples. The findings indicated a higher presence of reactive compounds in the aerial samples. The sample pairs exhibited relatively homogeneous compositions of hydrocarbons with fewer than eight carbon atoms, suggesting a well-mixed condition for light compounds. Conversely, the aerial samples exclusively exhibited high mixing ratios of C8–C15 compounds, including branched paraffins and aldehydes. Based on the quantified VOCs, we evaluated the ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAP). The results highlighted aldehydes, alkenes, and aromatics, particularly propanal, 2-butene, m/p-xylene, and benzaldehyde, as priority control compounds. Additionally, the semiquantitative concentrations of these non-quantitative C8–C15 species ranged from 1 to 15 ppbv, with a total content exceeding 150 ppbv, it indicated the significant contribution to ambient secondary pollution. These results provide valuable insights into the identification of potential emission sources and the assessment of environmental repercussions attributed to these intermediate-volatile organic compounds from fugitive emissions around petrochemical plant.

Extension of Methane Emission Rate Distribution for Permian Basin Oil and Gas Production Infrastructure by Aerial LiDAR.

Aerial LiDAR measurements at 7474 oil and gas production facilities in the Permian Basin yield a measured methane emission rate distribution extending to the detection sensitivity of the method, 2 kg/h at 90% probability of detection (POD). Emissions are found at 38.3% of facilities scanned, a significantly higher proportion than reported in lower-sensitivity campaigns. LiDAR measurements are analyzed in combination with measurements of the heavy tail portion of the distribution (>600 kg/h) obtained from an airborne solar infrared imaging spectrometry campaign by Carbon Mapper (CM). A joint distribution is found by fitting the aligned LiDAR and CM data. By comparing the aerial samples to the joint distribution, the practical detection sensitivity of the CM 2019 campaign is found to be 280 kg/h [256, 309] (95% confidence) at 50% POD for facility-sized emission sources. With respect to the joint model distribution and its confidence interval, the LiDAR campaign is found to have measured 103.6% [93.5, 114.2%] of the total emission rate predicted by the model for equipment-sized emission sources (∼2 m diameter) with emission rates above 3 kg/h, whereas the CM 2019 campaign is found to have measured 39.7% [34.6, 45.1%] of the same quantity for facility-sized sources (150 m diameter) above 10 kg/h. The analysis is repeated with data from CM 2020-21 campaigns with similar results. The combined distributions represent a more comprehensive view of the emission rate distribution in the survey area, revealing the significance of previously underreported emission sources at rates below the detection sensitivity of some emissions monitoring campaigns.

Volatile Organic Compound Sampling through Rotor Unmanned Aerial Vehicle Technique for Environmental Monitoring

To improve the capacity to probe volatile chemical substances in the atmosphere, we designed an unmanned aerial vehicle system for volatile organic compound (VOC) monitoring and sampling. This environmental monitoring unmanned aerial vehicle (EMUAV) platform was equipped with a photoionization detector for continuous VOC monitoring and searching in a pollution air mass. Furthermore, a multifunction airborne microVOC sampler was loaded for sampling. An airbag and absorption tube were applied to collect air samples for further analyzing in the laboratory by GC-FID/MS or TD-GC/MS. By comparing the aerial samples derived from the microVOC sampler with the samples collected at a similar height to a building roof for chemical compositions, the sampling conditions, such as the sampling port location and sampling method, were optimized to ensure the representativeness of the air samples. The results of the sample comparison experiment showed that both the airbag method and the adsorption method could recover 70–130% for most VOC species. Through the aerial measurements, the advantages of this EMUAV system were demonstrated. Therefore, the developed EMUAV system would have immeasurable potential in the field of environment monitoring.

Host plants and insecticides shape the evolution of genetic and clonal diversity in a major aphid crop pest.

Understanding the spatiotemporal dynamics of pesticide resistance at the landscape scale is essential to anticipate the evolution and spread of new resistance phenotypes. In crop mosaics, host plant specialization in pest populations is likely to dampen the spread of pesticide resistance between different crops even in mobile pests such as aphids. Here, we assessed the contribution of host-based genetic differentiation to the dynamics of resistance alleles in Myzuspersicae, a major aphid pest which displays several insecticide resistance mechanisms. We obtained a representative sample of aphids from a crop mosaic through a suction trap for 7years and from various crops as a reference collection. We genotyped these aphids at 14microsatellite markers and four insecticide-resistant loci, analyzed the genetic structure, and assigned host-based genetic groups from field-collected aphids. Four well-defined genetic clusters were found in aerial samples, three of which with strong association with host-plants. The fourth group was exclusive to aerial samples and highly divergent from the others, suggesting mixture with a closely related taxon of M.persicae associated with unsampled plants. We found a sharp differentiation between individuals from peach and herbaceous plants. Individuals from herbaceous hosts were separated into two genetic clusters, one more strongly associated with tobacco. The 4-loci resistance genotypes showed a strong association with the four genetic clusters, indicative of barriers to the spread of resistance. However, we found a small number of clones with resistant alleles on multiple host-plant species, which may spread insecticide resistance between crops. The 7-year survey revealed a rapid turn-over of aphid genotypes as well as the emergence, frequency increase and persistence of clones with resistance to several families of insecticides. This study highlights the importance of considering landscape-scale population structure to identify the risk of emergence and spread of insecticide resistance for a particular crop.

A study of the vertical homogeneity of trace gases in East Asian continental outflow

East Asian continental outflows containing with pollutants may deteriorate air quality in the downwind region via long-range transport (LRT). In particular, cold fronts with high wind speeds generally promote the LRT of air pollutants to further downwind areas, including Taiwan. To gain an insightful understanding of the characteristics and vertical homogeneity of trace gases in East Asian continental outflows, as well as their relation with atmospheric meteorological conditions, whole air samples were collected above a cape at the northern tip of the island of Taiwan during frontal passages. Aerial samples were collected at multiple altitudes from the surface to a maximum height of 700 m with a multicopter sounding platform carrying a robotic whole air sampling device. Simultaneously, aerial meteorological variables of temperature and wind vector from near the surface to a maximum height of 1000 m were also measured during the whole air sampling periods. An array of 106 volatile organic compounds (VOCs) as well as CO, CO2, and CH4 were analyzed to characterize the air composition and vertical homogeneity of trace gases. The results revealed rather homogeneous vertical distributions of most VOCs, CO, CO2, and CH4 in the frontal passages, indicating well-mixed conditions of trace gases in the East Asian continental outflows. The strong wind shear and minimal temperature inversion associated with the frontal passage likely induced turbulence and increased vertical mixing. Furthermore, higher levels of species characteristic of the East Asian continent were observed from the surface up to hundreds of meters above the cape, revealing a strong inflow of polluted air masses from the East Asian continent brought by cold frontal passages.

Comparative phytochemical analysis of the aerial parts of Empetrum nigrum L. samples, collected in various regions of the Russian Federation

Introduction. A number of studies have shown that various genetic and environmental factors can affect the biosynthesis and accumulation of secondary metabolites. In particular, it is known that the local geoclimate, seasonal changes, external conditions such as light, temperature, moisture and soil fertility can affect the chemical composition and, as a result, the therapeutic properties of plants used in the pharmaceutical and food industries. Empetrum nigrum L. is a rich source of various pharmacologically active secondary metabolites – chalcones, dihydrochalcones, bibenzyls, 9,10-dihydrophenanthrenes, flavonoids, and proanthocyanidins. In the scientific literature, there is no data on the variation in the chemical composition of E. nigrum depending on the growing area. The obtained data are necessary for a reasonable choice of the collecting location for the plant, with the aim of its further chemical and pharmacological research for the development of promising drug candidates.Aim. To carry out a comparative analysis of secondary metabolites composition in the aerial parts of Empetrum nigrum growing in different regions of the Russian Federation.Materials and methods. Samples collected in three different areas were used to compare HPLC profiles: sample 1 was collected next to SPCPU nursery garden of medicinal plants (Leningrad region, Vsevolozhsky district, Priozerskoe highway, 38 km) in July 2020, sample 2 was collected on the Kola Peninsula, around the Khibiny mountains in July 2020, sample 3 was collected on the Kamchatka Peninsula, next to Khalaktyrsky beach (Pacific Ocean coast) in July 2020. Extracts were analyzed by analytical high performance liquid chromatography (HPLC) using a Prominence LC-20 device (Shimadzu, Japan) equipped with a diode array detector.Results and discussion. As a result of the research, for the first time, a significant variation in the qualitative chemical composition in the aerial parts of Empetrum nigrum growing in different regions of Russian Federation was established. Sample 3, collected on the Kamchatka Peninsula, in comparison with samples 1 and 2, contain the greatest variety of polar secondary metabolites belonging to the classes of flavonoids, tannins, and phenol carboxylic acids, while in the shoots collected in the Leningrad region, the major metabolites were weakly polar compounds belonging to the classes of chalcones, dihydrochalcones, bibenzyls, and 9,10-dihydrophenanthrenes, and in sample 2, collected in the Khibiny mountains, the lowest qualitative content of secondary metabolites was found. This variation may be caused by various environmental factors (biotic and abiotic).Conclusion. For the first time, the comparison of HPLC profiles of aerial part samples of E. nigrum, collected in different regions of the Russia Federation has been carried out. As a result, significant variations in the secondary metabolites composition of the studied samples were established, depending on the regions and growing conditions of the plants. The data obtained can be used for a reasonable choice of the collection location for the plant, with the aim of its further chemical and pharmacological research for the development of promising drug candidates.

Tetrastigma leucostaphylum (Dennst.) Alston ex Mabb. Partial Wedge Sampling, a New, Less-invasive Solution for Stem-borne versus Root-borne Rafflesia Identification

Tetrastigma (Vitaceae) are a genus of tropical lianas that are hosts for parasitic plants in the family Rafflesiaceae. Since the stem of Tetrastigma is creeping and often devoid of leaves, it is often mistakenly visually identified as a root. Rafflesia flowers at the ground level (i.e. terrestrial flowers) have been documented to grow on Tetrastigma roots, but it is unclear whether those that arise aerially emerge from host root or stem organs. In this study, we present a new, lessdestructive means of sampling Tetrastigma leucostaphylum, which is a host of many Rafflesia species. Histological observation of two 250 cm above-ground aerial samples confirmed that both were stems, as shown by distinct anatomical features (compactly arranged vascular bundles with simple phloem bundles) in contrast to roots, which had loosely arranged vascular bundles with ramified phloem bundles. Clearer identification of Tetrastigma vine infected with aerial Rafflesia is needed to confirm whether the parasitic flower grows on a stem or on an erect aerial root to better understand the biology of this enigmatic Rafflesia species that have evaded cultivation and ex situ conservation efforts. This new sampling method may be a useful way to identify the Tetrastigma vine in the future due to its less invasive nature compared to severing the whole vine.

Temporal patterns of airborne Phytophthora spp. in a woody plant nursery area detected using real-time PCR

In this study, spore trap monitoring was applied to provide a proof of concept for the use of qPCR to detect Phytophthora in aerial samples and provide valuable information for epidemiological studies in nurseries. Two qPCR TaqMan assays were developed to detect pathogen DNA: the first used a generic probe to detect Phytophthora spp., and the second was based on a specific probe for detecting P. ramorum and P. lateralis. All samples tested positive for the genus Phytophthora, although P. ramorum and P. lateralis were not detected. In late spring and in autumn, two main peaks of Phytophthora sporulation were observed. Peaks were preceded by rainfall, high relative humidity, and mild temperature. From mid-May to the end of August, Phytophthora DNA detected in the air increased with relative humidity, while it decreased with increasing mean temperature. There was also a positive correlation between Phytophthora DNA detected and rainfall in the same period. No significant correlations between Phytophthora DNA and temperature or rainfall were found from the end of August to December. Our results are in agreement with those obtained with classical diagnostic methods based on microscopy, but the approach used here enabled rapid detection and relative quantification of the target organisms, thus assisting in the implementation of disease management strategies.

A study of atmospheric mixing of trace gases by aerial sampling with a multi-rotor drone

We exploited a novel sampling vehicle, a multi-rotor drone carrying a remote-controlled whole air sampling device, to collect aerial samples with high sample integrity and preservation conditions. An array of 106 volatile organic compounds (VOCs), CO, CH4, and CO2 were analyzed and compared between the aerial samples (300-m height) and the ground-level samples in pairs to inspect for vertical mixing of the trace gases at a coastal site under three different meteorological conditions of local circulation, frontal passage, and high-pressure peripheral circulation. A rather homogeneous composition was observed for the sample pairs immediately after the frontal passage, indicating a well-mixed condition below 300 m. In contrast, inhomogeneous mixing was observed for the sample pairs under the other two conditions (local circulation and high-pressure peripheral circulation), suggesting different layers of air masses. Furthermore, information of unique source markers, composition profiles, and lifetimes of compounds were used to differentiate the origins of the air masses aloft and at the surface to substantiate the observed inhomogeneity. The study demonstrates that, with the availability of the near-surface aerial sampling coupling with in-laboratory analysis, detailed compositions of trace gases can now be readily obtained with superior data quality. Based on the distinctive chemical compositions, the sources, transport, and atmospheric mixing of the airborne pollutants in the near-surface atmosphere can be better studied and understood.

Population dynamics of the Taimyr wild reindeer herd

The paper analyses with a range of historical data the dynamics of the Taimyr wild reindeer population. Its first period is a pre-commercial hunting period (1959–1971). The second is the period of intensive organised commercial hunting (1972–1993). The third is a post-commercial hunting period (1994–2007). Finally, there is the period of barbarity (2008 – present time). The analysis covers the dynamics of the size, sex and age structure of the population (according to the data of aerial census survey and commercial hunting samples), female barrenness, animals’ natural mortality, commercial hunting and productivity of the population. It has been demonstrated that the predominance of males in the sex and age structure of the population begins mainly at the beginning of animals’ lives. The analysis of the data on reindeer’s fertility and mortality (both natural and from commercial hunting) lead us to the conclusion that the most productive indices of the population were reached in the period of intensive organised commercial hunting. It has been demonstrated through the latest data that uncontrolled poaching might very soon lead to the destruction of this unique biological resource.

Impact of Arceuthobium sichuanense infection on needles and current-year shoots of Picea crassifolia and Picea purpurea in Qinghai Province, China

Arceuthobium sichuanense is an aerial parasitic plant (dwarf mistletoe) which causes severe damage to spruce forests on the Qinghai-Tibet Plateau. Picea crassifolia and Picea purpurea, two main host species of A. sichuanense, have different growth characteristics and elevational distributions. The effects of A. sichuanense infection on P. crassifolia and P. purpurea trees were evaluated by examining needle and current-year shoot morphology, needle water use efficiency and needle nitrogen concentration, with 30 needle samples, 30 current-year shoot samples and 10 A. sichuanense aerial shoot samples for each host species. The most apparent effects were significant reductions in both needle size and current-year shoot length. The high degree of correlation in foliar δ 15N values between the dwarf mistletoe and its host trees indicated that nitrogen in the dwarf mistletoe was derived entirely from its host. Percent reductions in needle and current-year shoot length were smaller for P. purpurea than for P. crassifolia, possibly suggesting that P. purpurea exhibits a lesser capacity to accommodate the parasitic effects of mistletoe infection by adjusting the growth of needles and current-year shoots. The reductions in needle nitrogen concentration and δ 13C values were lower in P. purpurea than in P. crassifolia, indicating that P. purpurea suffered more nitrogen and water stresses and exhibited lower vigor compared to P. crassifolia. Our results demonstrated that P. purpurea may suffer more negative effects induced by dwarf mistletoe infections at needle and branch levels than P. crassifolia.

Adult carrion fly (Diptera: Calliphoridae) visitation patterns by time of day at sunlit versus shaded pig carrion in southwestern West Virginia, USA.

A study to determine adult visitation patterns of two forensically important carrion flies (Diptera: Calliphoridae), Phormia regina (Meigen) and Lucilia (= Phaenecia) coeruleiviridis Macquart, was conducted at a wildlife management area in southwestern West Virginia. Pig carcasses (Sus scrofa L.) were used as surrogates for human bodies in sunlit vs. shaded field plots in four separate experimental periods; May of 2006, 2007 and 2008, and June of 2008. Aerial collection samples revealed that the proportion of P. regina was greater at sunlit carcasses than shaded ones, whereas the reverse was true for L. coeruleiviridis. Phormia regina adults, either alone or co-occurring with L. coeruleiviridis, were the first to arrive at sunlit carcasses, but L. coeruleiviridis consistently made up the “first arrivals” at shaded carcasses. Both species were most frequently collected at 2:00 p.m. and least likely to be collected at 8:00 a.m. on sunlit carcasses for all experimental periods. At shaded carcasses both species were least likely collected at 8:00 a.m., but P. regina and L. coeruleiviridis were most commonly collected at 2:00p.m. and 8:00 p.m., respectively. Sex ratios for both carrion fly species were decidedly female-biased in sunlit and shaded conditions.

Report on the Malungo expedition to the Erepecuru river, Oriximiná, Brazil. Part I: is there a difference between black and white breu?

Species belonging to Burseraceae produce an oleoresin known in the north of Brazil as breu. They comprise an essential oil with a complex composition, and are used in Amazonia for smoking the environment, to caulk boats and for medicinal purposes. Depending on its organoleptic characteristics and on the breu-producing species, they are called white or black breu. In this work, we provide data about the breu-producing species occurring in the quilombola region of the Erepecuru river, the chemical composition, and whether it is possible to differentiate them based on their chemical composition and/or botanical identification. Aerial samples from breu trees and oleoresins were collected from 10 different individuals at 6 different sites on the Erepecuru river under the guidance of the quilombolas. Essential oils were extracted by hydrodistillation and characterized by GC–MS. From the analysis, 126 different substances were identified, with a large quantitative and qualitative variation. To better understand the chemical variations within the samples and to sort the variation into the categories of white or black breu as identified by the quilombola, we sorted the oil samples into five different sets according to their major compounds (A: δ-3-carene; B: p-cymene; C: γ-cadinene/p-cymene; D: limonene, β-phellandrene/α-terpineol; E: α-pinene/limonene). Essential oils from samples of white breu had the highest concentration of α-pinene, while a similarity in chemical composition could not be established for the black breu samples (sets A, B and C). Furthermore, a chemical similarity between a black breu (Protium heptaphyllum (Aubl.) Marchand) and a white breu (Protium decandrum (Aubl.) Marchand) sample was evidenced. In conclusion, it is difficult to establish definitions for white and black breu based on chemical, botanical or regional names. This designation is more cultural and regional than scientific and is based on the oleoresin production volume, its color aspect and scent.

Activities and Prevalence of Proteobacteria Members Colonizing Echinacea purpurea Fully Account for Macrophage Activation Exhibited by Extracts of This Botanical.

Evidence supports the theory that bacterial communities colonizing Echinacea purpurea contribute to the innate immune enhancing activity of this botanical. Previously, we reported that only about half of the variation in in vitro monocyte stimulating activity exhibited by E. purpurea extracts could be accounted for by total bacterial load within the plant material. In the current study, we test the hypothesis that the type of bacteria, in addition to bacterial load, is necessary to fully account for extract activity. Bacterial community composition within commercial and freshly harvested (wild and cultivated) E. purpurea aerial samples was determined using high-throughput 16S rRNA gene pyrosequencing. Bacterial isolates representing 38 different taxa identified to be present within E. purpurea were acquired, and the activity exhibited by the extracts of these isolates varied by over 8000-fold. Members of the Proteobacteria exhibited the highest potency for in vitro macrophage activation and were the most predominant taxa. Furthermore, the mean activity exhibited by the Echinacea extracts could be solely accounted for by the activities and prevalence of Proteobacteria members comprising the plant-associated bacterial community. The efficacy of E. purpurea material for use against respiratory infections may be determined by the Proteobacterial community composition of this plant, since ingestion of bacteria (probiotics) is reported to have a protective effect against this health condition.

Development of a multicopter-carried whole air sampling apparatus and its applications in environmental studies

To advance the capabilities of probing chemical composition aloft, we designed a lightweight remote-controlled whole air sampling component (WASC) and integrated it into a multicopter drone with agile maneuverability to perform aerial whole air sampling. A field mission hovering over an exhaust shaft of a roadway tunnel to collect air samples was performed to demonstrate the applicability of the multicopter-carried WASC apparatus. Ten aerial air samples surrounding the shaft vent were collected by the multicopter-carried WASC. Additional five samples were collected manually inside the shaft for comparison. These samples were then analyzed in the laboratory for the chemical composition of 109 volatile organic compounds (VOCs), CH4, CO, CO2, or CO2 isotopologues. Most of the VOCs in the upwind samples (the least affected by shaft exhaust) were low in concentrations (5.9 ppbv for total 109 VOCs), posting a strong contrast to those in the shaft exhaust (235.8 ppbv for total 109 VOCs). By comparing the aerial samples with the in-shaft samples for chemical compositions, the influence of the shaft exhaust on the surrounding natural air was estimated. Through the aerial measurements, three major advantages of the multicopter-carried WASC were demonstrated: 1. The highly maneuverable multicopter-carried WASC can be readily deployed for three-dimensional environmental studies at a local scale (0−1.5 km); 2. Aerial sampling with superior sample integrity and preservation conditions can now be performed with ease; and 3. Data with spatial resolution for a large array of gaseous species with high precision can be easily obtained.

Análisis de la vegetación herbácea no gramínea y su relación con el banco de semillas en dos espacios verdes de la ciudad de La Plata, Argentina

Analysis of non-grass herbaceous vegetation in relation to the seed bank in two green spaces in La Plata city, Argentina. Urban green areas are under intense anthropogenic influence and often include a high proportion of native and/or exotic species, intentionally and/or accidentally introduced. The aim of this paper is to analyze and compare two green areas in La Plata city: a) the specific richness of non-grass herbaceous vegetation in association with grass lawns; b) the diversity and composition (qualitative and quantitative) of the soil seed bank; c) correspondence between aerial vegetation and seed bank. The analized sites were Parque Alberti and a sector of Paseo del Bosque of the city. Plants were collected from the aerial community and soil samples along transects, in four different seasons. Removal of seeds from soil samples was performed using the washing technique. There were a total of 37 species collected in 33 genera and 15 families, of which 15 species and 8 families were common to both studied areas. The qualitative similarity between the studied areas was medium (SI = 0.57) and quantitative between seed banks was low (MI = 0.36). The Paseo del Bosque sector showed the greatest wealth of aerial flora species and a high proportion of native species while the corresponding seed bank showed the highest values of floristic richness indices (R = 0.51), diversity (H ‘= 2.17) and evenness (J’ = 0.63), these observations indicate a lower frequency and intensity of disturbances in comparison with the Parque Alberti.

MOLECULAR AND VOLATILES CHARACTERIZATION OF PORTUGUESE THYMUS CAESPITITIUS CHEMOTYPES

21 individual aerial parts samples of Thymus caespititius were collected on Terceira, Sao Jorge, Flores and Graciosa (Azores) and on the mainland north of Portugal. The molecular approach was performed using 10 ISSR primers generating a total of 176 polymorphic bands. On the basis of the ISSR patterns, the individuals were grouped into 4 clusters with low correlation (S DICE =0.18) due the high genetic polymorphism detected (98.9%). Isolated by distillation-extraction, the volatiles were analyzed by GC and GC-MS. The volatile cluster analysis allowed samples separation on thymol, carvacrol, α-terpineol and sabinene chemotypes. No straight correlation between molecular and chemical assessments could be found. Other tools, such as terpene synthases studies, are currently under way to try to improve the understanding on this species chemical polymorphism.

THE ENGLISH BEECH MASTING SURVEY 1980–2007: VARIATION IN THE FRUITING OF THE COMMON BEECH (FAGUS SYLVATICA L.) AND ITS EFFECTS ON WOODLAND ECOSYSTEMS

Summary 1. Study of annual production of beech mast at twelve main sites including closed canopy beechwood, shelter belts, avenues and an isolated tree in a park, as well as intermittent observations at others, has now continued for twenty-eight years. 2. During this period beech mast was sampled from up to 100 trees by seven-minute samples collected from the ground. Aerial samples have also been collected from low-growing branches. 3. Production of full seed varies greatly from year to year, and all trees produce empty pericarps as well as full mast, especially on lower or shaded branches. 4. The proportion of full nuts consumed or damaged by the moth Cydia fagiglandana Z., birds and small mammals, in English sites, can become significant especially in non-mast years. 5. Good masting occurred in 1980, 1982, 1984, 1987, 1990, 1995, 1997, 2000, 2002, 2004 and 2006: after each of these good years, one year of very poor masting normally followed. The best year recorded so far was 1990. In both 1981 and 2005, no full mast was found, and singularly very little in 1991 and 2001. 6. Regional variation within England is much less than the annual variation, but over the period the northern trees have produced on average fewer full nuts but rather more empty and total nuts. In 2007, however, northern trees produced markedly less full and total nuts than their southern counterparts. 7. Over such a long period it was inevitable that site changes would occur. In some instances the substrate beneath particular trees is now less favourable for rapid nut collection. As some trees have died, additional younger trees are now being assessed. In 1996, far more viable seed was formed in certain Scottish sites than at those we observed in England, so it is highly desirable that Scottish and Welsh sites be monitored in the future.

Ground-Cover Measurements: Assessing Correlation Among Aerial and Ground-Based Methods

Wyoming's Green Mountain Common Allotment is public land providing livestock forage, wildlife habitat, and unfenced solitude, amid other ecological services. It is also the center of ongoing debate over USDI Bureau of Land Management's (BLM) adjudication of land uses. Monitoring resource use is a BLM responsibility, but conventional monitoring is inadequate for the vast areas encompassed in this and other public-land units. New monitoring methods are needed that will reduce monitoring costs. An understanding of data-set relationships among old and new methods is also needed. This study compared two conventional methods with two remote sensing methods using images captured from two meters and 100 meters above ground level from a camera stand (a ground, image-based method) and a light airplane (an aerial, image-based method). Image analysis used SamplePoint or VegMeasure software. Aerial methods allowed for increased sampling intensity at low cost relative to the time and travel required by ground methods. Costs to acquire the aerial imagery and measure ground cover on 162 aerial samples representing 9000 ha were less than $3000. The four highest correlations among data sets for bare ground--the ground-cover characteristic yielding the highest correlations (r)--ranged from 0.76 to 0.85 and included ground with ground, ground with aerial, and aerial with aerial data-set associations. We conclude that our aerial surveys are a cost-effective monitoring method, that ground with aerial data-set correlations can be equal to, or greater than those among ground-based data sets, and that bare ground should continue to be investigated and tested for use as a key indicator of rangeland health.