Field Seasons Research Articles

Quantifying the abundance and survival rates of island-associated spinner dolphins using a multi-state open robust design model

Spinner dolphins (Stenella longirostris subsp.) occupy the nearshore waters of several Hawaiian Islands. Due to their constrained behavioral pattern and genetic isolation, they are vulnerable to anthropogenic threats. Their occurrence and behavior are well-described, yet a lack of data on their abundance and survival rates hinders optimal conservation action. Using design-based photo-identification surveys, this study estimated the abundance, apparent survival, and emigration of spinner dolphins off the Waiʻanae Coast of Oʻahu through multi-state open robust design (MSORD) and POPAN modelling. Eight seasonal field seasons, (two winter, spring, summer, and autumn) each comprised of six surveys of the study area, were completed during two consecutive years. Seasonal abundance estimates derived from the best fitting model ranged from 140 (± 36.8 SE, 95% CI 84–232) to 373 (± 60.0, 95% CI 273–509) individuals and were lowest during winter seasons. The MSORD estimated a survival rate of 0.95 (± 0.02 SE) and a Markovian pattern of temporary emigration. POPAN modelling estimated a super-population size of 633 (± 78 SE, 95% CI 492–798), reflecting the total number of individual dolphins that used the study area during the entire study period. Additional research on circum- and inter-island dolphin movements around and between Oʻahu and the Maui Nui region may shed light on both seasonal movement patterns and overall abundance for the Oʻahu/4-Islands stock. This work represents the first systematic mark-recapture effort to assess the abundance and survival rates of these highly exposed dolphins, providing valuable insights for conservation and management.

Gazing Strategies among Sentinels of a Cooperative Breeder Are Repeatable but Unrelated to Survival.

Vigilance is a common behavioural adaptation to increase the chances of detecting predators before it is too late to escape. Behavioural traits are often repeatable among individuals over the long term, suggesting differences in personality. Earlier studies have documented individual consistency in the time allocated to vigilance. However, little is known about individual consistency in the ways vigilance is achieved from one moment to another and whether different patterns of vigilance among individuals are associated with survival. We aimed to determine whether sentinels of a cooperative breeder showed individual consistency in their vigilance and if individual variation was related to annual survival. During sentinel bouts from vantage points, Florida scrub-jays (Aphelocoma coerulescens) turn their heads from side to side to monitor their surroundings. Over three field seasons, we found that the head-turning frequency was repeatable in breeders but not in juveniles or non-breeding helpers. The moderate repeatability in breeders was not related to survival. Our results suggest that the head-turning frequency in sentinels of the Florida scrub-jay is repeatable in breeders but not in less experienced juveniles or helpers and, therefore, likely becomes more repeatable as individuals age. The assumption that individual variation in vigilance is related to survival was unsupported in our study and requires further study.

Lithium Concentrations in Saline Brines of the Shu–Sarysu Depression

This article presents the results of a study on lithium mineralization in salt flats and underground aquifers of the Shu–Sarysu depression. Analysis of brine samples collected from 2022 to 2023, utilizing spectroscopy and X-ray diffraction, reveals elevated concentrations that hold commercial promise. These findings may have significant implications for exploration efforts and estimation regarding the lithium resource potential, which is currently in high demand. This article examines data regarding lithium brine deposits worldwide, focusing on their geology. The research methodology involves delineating regions of salt flat distribution through remote sensing data interpretation, fieldwork, and laboratory analysis, particularly for surface brines. Underground lithium-bearing brines are detected within oil and gas structures. The article presents findings from analytical studies conducted on saline and co-produced formation brines collected during the 2022 field season, with a specific focus on the epiplatform regions of Kazakhstan, encompassing the Shu–Sarysu depression.

Brown planthoppers manipulate rice sugar transporters to benefit their own feeding

The feeding of piercing-sucking insect herbivores often elicits changes in their host plants that benefit the insect.1 In addition to thwarting a host's defense responses, these phloem-feeding insects may manipulate source-sink signaling so as to increase resources consumed.2,3 To date, the molecular mechanisms underlying herbivore-induced resource reallocation remain less investigated. Brown planthopper (BPH), an important rice pest, feeds on the phloem and oviposits into leaf sheaths. BPH herbivory increases sugar accumulations 5-fold in the phloem sap of leaf sheaths and concurrently induces the expression of two clade III SWEET genes, SWEET13 and SWEET14, in leaf tissues, but not in leaf sheaths of attacked rice plants. Mutations of both genes by genome editing attenuate resistance to BPH without alterations of known chemical and physical defense responses. Moreover, BPH-elicited sugar levels in the phloem sap were significantly reduced in sweet13/14 mutants, which is likely to attenuate BPH feeding behavior on sweet13/14 mutants. In one of the two field seasons tested, the sweet13/14 mutants showed comparable yield to wild types, and in the other season, the mutants demonstrated stronger BPH resistance. These preliminary results suggested that the mutations in these SWEET transporters could enhance BPH resistance without yield penalties. Given that sweet13/14 mutants also exhibit resistance to bacterial blight pathogen, Xanthomonas oryzae pv. oryzae, these SWEET genes could serve as excellent molecular targets for the breeding of resistant rice cultivars.

Excavations at Poggio Civitate (Murlo): The 2023 Field Season

Abstract Excavation during the 2023 field season at Poggio Civitate focused on areas immediately west of Piano del Tesoro and further refined our understanding of the form and development of the building known as Early Phase Orientalizing Complex Building 4 (abbreviated EPOC4). In addition, excavation re-examined the western area of Orientalizing Complex Building 2/Workshop (abbreviated OC2/Workshop) as well as areas immediately north of OC2/Workshop.

Ten simple rules for implementing a successful field season.

Ten simple rules for implementing a successful field season.

Landscapes with higher crop diversity have lower aphid species richness but higher plant virus prevalence

Abstract Diversifying agricultural systems by growing more than one crop species in an area can decrease pest and disease pressure and increase crop yields. However, there is a lack of information on how crop diversity at larger spatial scales influences pest and disease pressure. Here, we investigated how landscape‐scale crop diversity affects aphid vector communities and prevalence of non‐persistently transmitted potato virus Y (PVY). To test the influence of landscape‐scale crop diversity on PVY prevalence and aphid communities, we conducted a field study during the 2020 and 2021 field seasons in the San Luis Valley, Colorado, where we quantified aphid communities and PVY incidence at multiple sites. We then determined the association between aphid species richness and abundance and PVY incidence with landscape variables (crop diversity metrics and percentage cover of crop species) within 1, 2 and 3 km buffers from study sites. Higher crop diversity (measured as Shannon Diversity Index) led to decreased aphid species richness at a 3 km buffer in the 2021 field season. We only detected a positive association between percentage of alfalfa crop cover and aphid species richness in 2020 and aphid abundance in 2021 within a 1 km buffer. Higher crop diversity led to increased PVY incidence at a 2 km buffer in 2021 and 3 km buffer in 2020 and 2021. At a 3 km buffer in 2021, we found a positive influence of crop species richness on PVY incidence and a negative influence of crop species evenness on PVY incidence. Also in 2021, we found a positive influence of percentage of potato (virus host) on PVY incidence and a negative influence of percentage of barley (virus non‐host) on PVY incidence. Synthesis and applications. In summary, we found that landscape‐scale crop diversity impacts plant virus prevalence at spatial scales of >1 km. This suggests that potato growers could reduce PVY prevalence by geographically isolating potato fields from other potato or other PVY hosts. Crop diversity had a negative influence on aphid vector communities, so growers could reduce risk of virus spread by aphid vectors by using certified potato seed in a diversified landscape.

Genetic control of root architectural traits under drought stress in spring barley (Hordeum vulgare L.).

Root architectural traits play pivotal roles in plant adaptation to drought stress, and hence they are considered promising targets in breeding programs. Here, we phenotyped eight root architecture traits in response to well-watered and drought stress conditions in 200 spring barley (Hordeum vulgare L.) inbred lines over two consecutive field seasons. Root architecture traits were less developed under drought in both seasons when compared with control treatments. Genetic variation in root architectural traits was dissected employing a genome-wide association study (GWAS) coupled with linkage disequilibrium mapping. GWAS uncovered a total of 186 significant single nucleotide polymorphism-trait associations for eight root traits under control, drought, and drought-related indices. Of these, a few loci for root traits were detected on chromosomes 3 and 5, which co-located with QTL identified in previous studies. Interestingly, 13 loci showed simultaneou associations with multiple root traits under drought and drought-related indices. These loci harbored candidate genes, which included a wide range of drought-responsive components such as transcription factors, binding proteins, protein kinases, nutrient and ion transporters, and stress signaling factors. For instance, two candidate genes, HORVU7Hr3G0713160 and HORVU6H r3G0626550, are orthologous to AtACX3 and AtVAMPs, which have reported functions in root length-mediated drought tolerance and as a key protein in abiotic stress tolerance, respectively. Interestingly, one of these loci underlying a high-confidence candidate gene NEW ENHANCER OF ROOT DWARFISM1 (NERD1) showed involvement with root development. An allelic variation of this locus in non-coding region was significantly associated with increased root length under drought. Collectively, these results offer promising multi-trait affecting loci and candidate genes underlying root phenotypic responses to drought stress, which may provide valuable resources for genetic improvement of drought tolerance in barley.

Ensembles of multiple models for soil moisture retrieval from remote sensing data over agricultural areas: A deep learning-based framework

In agricultural areas, most surface soil moisture (SM) retrieval models are unstable in terms of their accuracy and performance during crop growth. As a result, there is no consensus on which model performs optimally during the agricultural season. This is because of the uncertainties associated with model physics, initial conditions, model inversion processes, input data, vegetation attenuation and soil characteristics. To better deal with these practical concerns, we propose a simple, but robust SM retrieval method of using combination of multiple models based on deep learning and multi-model ensemble approach, called the DL-MME method, which makes use of the ‘collective intelligence’ and ‘wisdom of crowds’ concepts. The advantages of this method are: (1) robustness to model selection, and (2) robustness to model calibration during the growing season. In addition, this method is less dependent on one type of data across various agricultural areas compared to the single model approach. Firstly, the coupled water cloud model (WCM) and soil backscattering models (Oh model or advanced integral equation model (AIEM)) with different vegetation descriptors were calibrated and validated during the growing season in sugarcane and winter wheat fields for Sentinel-1 backscattering coefficients (VV and VH). SM was also retrieved by employing the trapezoid model (OPTRAM) with different parameters from Sentinel-2 images. To optimize SM retrieval computations, we used the outputs from optical and SAR models, auxiliary features, and reliable in situ SM measurements as inputs to a deep learning convolutional neural network (DL-CNN). For sugarcane and wheat fields in the early stages of crop growth, WCM models retrieved more accurate time-series SM than optical models. OPTRAM soil moisture retrievals showed greater accuracy in the late crop growing season. Time-series SM retrieval accuracy using DL-MME was higher than for the optical and semi-empirical SAR models. According to the results of the in situ validation for wheat (sugarcane) fields, the minimum MAE by an optimal combination of models was around 0.01 (0.02) m3m−3 (RMSE = 0.036 (0.074) m3m−3; R = 0.87 (0.71)). The findings demonstrate that our method is reliable and feasible for SM retrieval. Additionally, our method provides a way to select an optimal model for retrieving time-series SM during the crop growing season.

A Paperless and 3D Workflow for Documenting Excavations at Insula I.14, Pompeii, Italy

ABSTRACTIn the summer of 2022, Tulane University, in collaboration with archaeologists from other institutions, began excavations at the site of Pompeii. The archaeological work was focused on Insula 14 of Region 1, located in the southeastern sector of the site. To overcome the challenges of recording a complex urban excavation, and of working with a collaborative team, we designed and implemented a unique workflow that combines paperless and 3D data-capture methods through the use of GIS technologies. The final product of our documentation workflow was a robust and easy-to-use online geodatabase where archaeologists can revisit, explore, visualize, and analyze each excavated context using virtual tools. We present our workflow for digitally documenting observational and spatial data in the field, and how we made these data available to project archaeologists during and after the field season. First, we describe the development of digital forms in ESRI's Survey123. Then, we explain our procedures for 3D documentation through SfM photogrammetric methods and discuss how we integrated the data and transformed it into an accessible format by using interactive dashboards and online 3D web scenes. Finally, we discuss the components of our workflow that are broadly applicable and that can easily be adapted to other projects.

Influence of strip-tillage and winter cover crops on weeds and yield in organic pepper

Increasing vegetation diversity within crop fields through cover cropping has been advocated as an additional tool for managing weeds. As such, field experiments were conducted over two field seasons to compare the influence of four cover cropping/tillage tactics on weeds, time spent manually removing weeds and marketable yields in organic bell peppers (Capsicum annuum). The four treatments included: (1) conventional till (CT), (2) no-till (NT), (3) strip till after roller-crimping (ST-RC), and (4) strip till with a living mulch between crop rows (ST-LM). Impacts of cover crop on the number of weeds encountered during the study differed according to how cover crops were managed, row region (intra- and inter-row) and weed characteristic (life cycle, type) and was not always consistent. The ST-LM treatment generally had the least amount of weed establishment and ground coverage in the inter-row crop area. The CT treatment contained more weeds than all treatments in intra- and inter-row areas in year 1. Perennial weeds were generally found in greatest biomass in the inter-row area of the NT treatment. Weeding times varied among years and were similar among treatments in season 1. However, in year 2, less time was required for hand weeding in CT than NT and ST-RC. The CT treatment contained the highest marketable fruit yield during year 1. However, in year 2 fruit yields were similar among treatments. Red clover can be used as a living mulch to effectively reduce weed pressure in vegetable crops, however competition between the clover and cash crop must be minimized, and additional intra-row weed management may be necessary.

Wolverine density, survival, and population trends in the Canadian boreal forest

AbstractThere is limited information available on wolverine (Gulo gulo) population density and trends in the boreal forest of North America. We estimated wolverine density using spatial capture‐recapture methods across 2 boreal forest study areas in Red Lake, Ontario (26,568 km2) and Rainbow Lake, Alberta (19,084 km2), Canada. We also used radio‐telemetry data to estimate annual survival of adult and sub‐adult wolverines and evaluated population trends with a stage‐based matrix model. We used an array of run poles and live traps to detect wolverines. In Red Lake over 3 winter field seasons (2019–2022), we detected 56 individual wolverines (17 females, 32 males, and 7 unknown sex), and in Rainbow Lake over 2 field seasons (2014–2016), we detected 48 individuals (19 females, 18 males, and 11 of unknown sex). Average densities in Red Lake and Rainbow Lake were 3.64 and 6.74 wolverines/1,000 km2, respectively. Adults and sub‐adults occurred at equal abundance. Spring snow cover, roads, and industrial developments were not associated with spatial patterns of wolverine density. Most deaths occurred near roads; wolverines were killed in fur traps set along roads, by wolves using roads to travel, and by vehicles. The largest source of death was from incidental (n = 6 in Red Lake) or licensed fur trapping (n = 8 in Rainbow Lake) and we report 8 injuries from fur trapping sets. Red Lake survival estimates for adults (0.87) and sub‐adults (0.86) contributed to a stable population trend. Rainbow Lake survival estimates for adults (0.66) and sub‐adults (0.50) contributed to a declining population trend based on a relatively low sample of radio‐days. Red Lake and Rainbow Lake combined survival estimates for adults (0.77) and sub‐adults (0.73) also contributed to a declining population trend. Our survival and population modeling suggests that human‐caused mortality is a significant risk to these populations. Our results can be applied to wolverine status assessments and used as benchmarks for future monitoring. Wolverine population stability or growth might be achieved by reducing incidental trapping deaths or injury and hindering human access to wolverine habitats through decommissioning or limiting development of industrial roads or other anthropogenic linear features.

Cauca: megafaunal and felid fossils (Mammalia) from a Pleistocene site in northwest Venezuela

Numerous surveys and three excavation and surface collection field seasons resulted in the discovery of numerous megafaunal remains and that of a medium-sized felid in a new site located on the coastal plain of the Gulf of Venezuela, in Western Falcón State. The faunal assemblage is represented by South American natives such as megatheres (cf. Eremotherium laurillardi), an indeterminate mylodontid and a glyptodont (probably related to Glyptotherium) and Nearctic representatives such as gomphotheres (Notiomastodon platensis), equids (Equus sp.) and a feline (Felidae cf. Leopardus pardalis), providing novel information for the distribution of some of these mammals. Radiocarbon indicates that this deposit is at least 40,000 years old. Lithic artefacts of a kind reported for other Pleistocene sites in the region document the presence of humans in Cauca, but as these cultural remains were found on the surface, their association with the fauna is uncertain.

Emergency Actions for the Documentation, Stabilization, and Consolidation of the Early Bronze Age Fortifications at Khirbat Iskandar, Jordan

Khirbat Iskandar is an Early Bronze Age (ca. 3800-1950 BCE) mound in the Madaba Governorate of Jordan. Until a decade ago, it was better known as a key site for the non-urban Early Bronze IV period (ca. 2500-1950 BCE), but is increasingly emerging as a signature site for the urban Early Bronze II-III period (ca. 3050-2500 BCE). The contour of the tall site is shaped by the presence of buried fortifications that were investigated in the north-western sector of the mound, where a long sequence of rebuilds was recognized, but were exposed to and impacted by modern construction activities along the southern and south-eastern areas prior to being recorded. There, due to erosion and weathering, the stone fortifications dating to the first half of the Early Bronze III (ca. 2850-2650 BCE) fell down. In this paper, we report on our strategies to assess threats, document damages, sustainably stabilize, and consolidate the collapsed ancient fortifications in the 2023 field season at Khirbat Iskandar. At the same time, we discuss the conceptual/methodological and practical challenges of identifying best practices in the conservation and preservation of antiquities that collapsed prior to being excavated. We conclude with some thoughts on how to build on these actions to efficiently present the archaeology and cultural heritage at protohistoric sites, like Khirbat Iskandar, and to make it accessible for the local and the international communities.

Frozen Bodies

This essay presents a visual journal that I created for a field season on Thwaites Glacier, Antarctica, as a way both to record states of dissociation/depersonalization and track my gender identity. Drawing on autoethnography as a method of inquiry, I created a pocket-sized journal of body outlines and used oil pastels to document my embodied and emotional responses to conducting fieldwork. I reflect on how my visual journal helped me understand how my body responded to living and working in extreme conditions, how my work and body relate to one another, and how the creation and completion of this journal gave me agency over my experiences of dissociation and queerness. Through this account, I aim to contribute to the growing literature on the personal and political dimensions of polar research—critical glaciology—as well as to demonstrate the potential of autoethnographic methods to facilitate embodied ways of knowing in deep field contexts.

Comparative genomics of a novel Erwinia species associated with the Highland midge (Culicoides impunctatus).

Erwinia (Enterobacterales: Erwiniaceae) are a group of cosmopolitan bacteria best known as the causative agents of various plant diseases. However, other species in this genus have been found to play important roles as insect endosymbionts supplementing the diet of their hosts. Here, I describe Candidatus Erwinia impunctatus (Erwimp) associated with the Highland midge Culicoides impunctatus (Diptera: Ceratopogonidae), an abundant biting pest in the Scottish Highlands. The genome of this new Erwinia species was assembled using hybrid long and short read techniques, and a comparative analysis was undertaken with other members of the genus to understand its potential ecological niche and impact. Genome composition analysis revealed that Erwimp is similar to other endophytic and ectophytic species in the genus and is unlikely to be restricted to its insect host. Evidence for an additional plant host includes the presence of a carotenoid synthesis operon implicated as a virulence factor in plant-associated members in the sister genus Pantoea. Unique features of Erwimp include several copies of intimin-like proteins which, along with signs of genome pseudogenization and a loss of certain metabolic pathways, suggests an element of host restriction seen elsewhere in the genus. Furthermore, a screening of individuals over two field seasons revealed the absence of the bacteria in Culicoides impunctatus during the second year indicating this microbe-insect interaction is likely to be transient. These data suggest that Culicoides impunctatus may have an important role to play beyond a biting nuisance, as an insect vector transmitting Erwimp alongside any conferred impacts to surrounding biota.

Organic compost belowground and floral diversity aboveground interactively shape beneficial insects in urban gardens

Abstract Plant diversity aboveground can exert top‐down pressure on herbivores by attracting predatory insects, while organic soil amendments rich in beneficial microbes can limit herbivores from the bottom‐up by enhancing plant defensive chemistry. Aboveground and belowground forces always operate simultaneously to shape herbivore pressure, but understanding how they interact is a longstanding and persistent challenge. Here, we examine how organic composts mediate the effects of plant diversity across trophic levels, using zucchini plants (Cucurbita pepo) as a study system. Over two field seasons, we manipulated vermicompost treatments in 18 experiments in school gardens that varied in surrounding plant and floral resource diversity and measured responses of insect herbivores and their natural enemies. Vermicompost strengthened a positive relationship between flower richness and foliar‐feeding omnivores, suggesting that robust reservoirs of omnivores at flower‐rich sites mounted stronger responses to compost‐treated host plants. Predators increased with flower richness, but were not affected by vermicompost. Net outcomes of vermicompost and plant diversity were neutral for herbivores. Synthesis and applications. Altogether, our results reveal that bottom‐up factors protecting plants are modified by their environmental context, and may more effectively attract natural enemies in landscapes with diverse floral resources. Therefore, we recommend augmentation of biodiversity aboveground (i.e. floral resources) together with biodiversity belowground (organic soil amendments) to strengthen crop protection.

К флоре мхов полуострова Кони (Ольский участок Государственного природного заповедника "Магаданский")

Based on the results of processing the materials collected during a few field seasons and considering the available publications, data on the mosses in the Ola lot of the Magadan Nature Reserve are presented. The list includes 138 species belonging to 67 genera and 35 families. Some peculiarities of the studied flora are discussed on the base of the data received.

Geoelectric model of the exposure of basement rocks to the surface in the Uimon depression of Gorny Altay based on three-dimensional numerical modeling

In the western part of the Uimon depression of the Altai Mountains, during the 2023 field season, additional measurements were carried out using electrical tomography along three profiles to clarify the structure of the area with basement rocks exposed to the surface. During the study, the results of three-dimensional inversion were obtained taking into account new electrical tomography data, and a refined geoelectric model of the study area was constructed. To verify the resulting model, 2D and 3D numerical modeling was performed with the help of which the geometric dimensions and electrical resistivity of bedrock outcrops were justified. The influence of the daytime surface topography on geoelectric sections in mountainous regions with significant differences in elevation on the earth's surface has been shown. Determining the structure of the depressions is necessary to understand the stages of neotectonic formation of the Uimon depression and the entire region, as well as to assess the seismic hazard of the Altai Mountains. In the course of further research, it is possible to trace the object to a greater depth (~100 m) using a three-electrode electrical tomography installation or alternative equipment with an increased size of the measuring-generator cable.

Introduced species infiltrate recent stages of succession after glacial retreat on sub-Antarctic South Georgia

Biological invasions are one of the main drivers of global biodiversity decline. At the same time, glacial retreat induced by climate warming is occurring at an alarming rate across the globe, threatening unique taxa and ecosystems. However, we know little about how introduced species contribute to the dynamics of colonisation in newly-deglaciated forelands. To answer this question, detailed inventories of plant and invertebrate communities were undertaken during two summer field seasons in the forelands of three tidewater and three inland glaciers that are retreating on the sub-Antarctic Island of South Georgia. The vascular plant communities present included a large proportion of South Georgia’s native flora. As expected, plant richness and cover increased with time since deglaciation along a deglaciation chronosequence. Introduced plants were well represented in the study sites and two species (Poa annua and Cerastium fontanum) were amongst the earliest and most frequent colonisers of recently-deglaciated areas (occurring on more than 75% of transects surveyed). Introduced arthropods were also present around tidewater glaciers, including an important predatory species (Merizodus soledadinus) with known detrimental impacts on native invertebrate communities. Our study provides a rare and detailed picture of developing novel communities along a deglaciation chronosequence in the sub-Antarctic. Introduced species are able to track glacial retreat on South Georgia, indicating that further local colonisation and spread are inevitable as the region’s climate continues to warm.