Cambrian-Ordovician (500 Ma) alkalic plutonism in southwestern New Mexico: U-Th-Pb isotopic data from the Florida Mountains
No abstract available.
New Mexico↗
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A geologic history of the north-central Appalachians. Part 1. Orogenesis from the Mesoproterozoic through the Taconic orogeny
The north-central Appalachians lie just southwest of the boundary between the central/southern and northern Appalachians, occupying a critical position within the 3000+ km-long Appalachian orogen. The history of tectonic activity in the north-central Appalachians spans more than one billion years, from the assembly and breakup of a Neoproterozoic supercontinent, through active orogenesis during Laurentia's Paleozoic northward journey off the western margin of West Gondwana, to the Mesozoic transformation of the active orogen into a passive margin during Pangea's disassembly. The major tectonic events include five compressional orogenies and two extensional episodes: 1. The late Mesoproterozoic Grenville orogeny assembled several continental masses into the Neoproterozoic supercontinent, Rodinia. It was the most widespread but now least exposed tectonism, and rocks involved in this event underlie as basement most of the exposed north-central Appalachians. Large fragments of Laurentian Grenville rock were subsequently broken off and incorporated in later Appalachian orogenesis. 2. Crustal extension and rifting late in the Neoproterozoic and into the earliest Cambrian separated Laurentia from West Gondwana, thereby forming the intervening Theic ocean and two continental rifts on Laurentia's eastern margin, the Catoctin rift and, later in the Middle? to Late Cambrian, the so-called "Rome" trough. The initial siliciclastic sedimentation on the margin migrated westward through time onto the craton, supplanted by a thick and increasingly wide carbonate shelf on Laurentia's eastern margin. Two microcontinents of Grenville-age, non-Laurentian(?) continental rock became positioned east of Laurentia, thereby creating the Octoraro sea as an arm of Theia. 3. In Theia, east of the two microcontinents, magmatic arcs developed over a subduction zone late in the Cambrian. Convergence within Theia caused the Potomac orogeny, which obduced the arcs (Wilmington Complex, Cecil Amalgamate) over the microcontinents and associated Theic deposits (including accretionary wedge sediments). 4. Continued westward convergence collapsed the Octoraro sea, producing the Middle to Late Ordovician Taconic orogeny in which the Potomac-deformed magmatic arcs and associated Theic elements were obduced onto the Laurentian continental margin. This obduction: drowned the carbonate shelf with siliciclastic sediments (Martinsburg Formation); drove continental rise and basinal deposits over the carbonate shelf on the Martic thrust; slid the Hamburg klippe onto the shelf; and accreted the Potomac package of microcontinent/arc/basinal-sediments onto the Laurentian margin. This orogeny transformed the broad Early Paleozoic carbonate shelf into the Appalachian basin that persisted throughout the Middle and Late Paleozoic. 5. The Middle Devonian Acadian orogeny ended the largely paralic environment that dominated the Appalachian basin during the Late Silurian. Active orogenesis in New England probably extended southward to the north-central Appalachians, because a vast amount of terrigenous sediment was introduced into the Appalachian basin to form the Catskill delta; however, evidence of actual Acadian deformation and metamorphism is lacking at this latitude. These presumed internal Acadides have yet to be found. 6. The convergence of West Gondwana and Laurentia during the Late Carboniferous and earliest Permian produced the Permian Alleghany orogeny in the north-central Appalachians. This widespread decollement tectonism directly affected a larger area of the presently exposed central and southern Appalachians than any earlier Paleozoic tectonic event. An early layer-parallel shortening phase gave way to a fold-thrust development above a basal decollement. This Alleghany fold-and-thrust tectonism created long, arcuate folds in the Appalachian basin. Late in the Alleghany orogeny, rock thrust northward over the Carboniferous rocks in the Anthracite region of northeastern Pennsylvania caused anthracitization of the underlying coals. The internal Alleghanides are not presently exposed. 7. Crustal extension in the Late Triassic and Early Jurassic produced numerous local, closed basins along eastern North America. Igneous intrusions and effusions marked the beginning of the Jurassic. By the end of the Early Jurassic, horizontal crustal rebound in response to opening of the Atlantic Ocean rotated the basins by crustal inversion, which folded some within-basin rocks and produced a prominent topographic ridge along the Piedmont, up-dip of the basins. Subsequent erosion of this Piedmont ridge and other parts of the Appalachian orogen fed large volumes of sediment to offshore basins during the remainder of the Mesozoic and throughout the Cenozoic. Each of these orogenies affected most of the Appalachian orogen. The tectonic expression of each orogeny varied along and across the orogen. The elements and structural bodies involved in each also varied along strike. However, many common elements persist from one part of the orogen to another; only a few features are singular in time and space. The tectonic boundary between the central and northern Appalachians is one of these singular features-it is solely an Alleghanian artifact.
American Journal of Science↗
A geologic history of the north-central Appalachians, part 2: The Appalachian basin from the Silurian through the Carboniferous
The north-central Appalachians occupy a critical position within the 3000+ km-long Appalachian orogen, lying southwest of the boundary between the central and northern Appalachians (CNAB). The one-billion-year-long history of tectonic activity in the north-central Appalachians includes the assembly and breakup of a late Proterozoic supercontinent, the creation and evolution of the Appalachian orogen during the Paleozoic, and the Mesozoic transformation of the active orogen into a passive margin during Pangea's disassembly. An important part of the Middle and Late Paleozoic history is the formation and growth of the Appalachian basin, an enormous, elongate continental basin lying cratonward of the active Appalachian internides along Laurentia's eastern margin. The Appalachian basin developed out of the Taconic orogeny, the second of the four orogenies that formed and modified the character of the Appalachian orogen. Prior to the Taconic orogeny, the eastern margin of Laurentia consisted of a broad carbonate shelf facing the Theic Ocean. The Taconic orogeny obduced various Theic components, including microcontinents, magmatic arcs, and accretionary prisms, onto the carbonate shelf. The resulting Taconic highlands formed a topographic barrier between Theia and the craton's interior. Because tectonic activity in the internides continued more or less throughout the remainder of the Paleozoic, the Appalachian basin never had a direct connection with Theia. The coarse-grained molasse from the newly uplifted Taconic highland spread westward over most of the basin during the Early Silurian. Carbonate deposition gradually encroached eastward over the basin as the siliciclastic input from the southeast waned. A resurgence in the earliest Late Silurian, perhaps related to orogenesis in Newfoundland and the Maritimes, expanded the clastic wedge somewhat. Before long, however, carbonate deposition once again dominated most of the north-central basin for the remainder of the Silurian and into the Early Devonian. The Early-to-Middle Devonian Acadian orogeny began introducing siliciclastic material into the eastern part of the Appalachian basin, thereby ending the largely paralic environment that persisted from the Late Silurian. A number of deltas formed around local sediment-input centers during the Middle Devonian. Continued uplift and/or orogenesis must have continued into the Late Devonian because a vast amount of terrigenous sediment was introduced into the Appalachian basin to form the vast Upper Devonian Catskill delta. Although the principal tectonic activity appears to have centered in New England, the large volume of sediment input suggests that orogenesis may have extended southward to the north-central Appalachians. However, direct evidence of actual Acadian deformation and metamorphism is lacking at this latitude. The north-central Appalachian basin underwent a significant change during the Carboniferous. Prior to this time, the shoreline shifted laterally through transgressions and regressions largely as a function of sediment input and regional subsidence. In the Carboniferous, vertical movements in the basin became more important. During the Early Carboniferous, much of the Mauch Chunk delta was eroded in the central and western parts of the basin. At the end of the Early Carboniferous, an unconformity truncated progressively older rocks to the north toward New York. New sediment transport patterns and depositional environments within the basin during the Late Carboniferous probably reflect significant topographic and tectonic changes, not only in the hinterland, but in the basin itself, perhaps in conjunction with climatic changes. Extensive interfluvial swamps on a lower delta plain accumulated thick organic deposits which would become coal. This delta plain graded southwestward into tidal and marine environments. The Alleghany orogeny in the Early Permian interrupted deposition in much of the north-central Appalachian basin and profoundly altered its structure.
American Journal of Science↗
A geologic history of the north-central Appalachians, part 3. The Alleghany orogeny
The north-central Appalachians occupy a critical position within the 3000+ km-long Appalachian orogen, lying southwest of the boundary between the central and northern Appalachians (CNAB). The one-billion-year-long history of tectonic activity in eastern Laurentia includes the creation and evolution of the Appalachian orogen during the Paleozoic and the Mesozoic transformation of the orogen into a passive margin during Pangea's disassembly. A most important ingredient in the evolution of the orogen was the Alleghany orogeny, which was driven by the convergence and collision between Laurentia (Laurussia) and West Gondwana (Africa). The Alleghany orogeny in the central and southern Appalachians was a decollement tectonism that involved a larger part of eastern Laurentia than had the previous three orogenies. The fundamental element was a very low-angle thrust (decollement) that originated in mid-crustal levels east of the presently-exposed Appalachians and rose westwardly to progressively higher levels in the upper crust and the supra-crustal Paleozoic section. Alleghany deformation was widely developed in the hanging-wall block (allochthon), primarily in the form of thrust faults and fold-and-thrust structures, both of which splayed upward from the basal decollement. The youngest manifestations of the Alleghany orogeny were northeast-trending strike-slip faults and dextral shear zones in the Piedmont. In the north-central Appalachians, the exposed allochthon consists of two parts: the sedimentary externides (Appalachian Plateau and Valley and Ridge provinces) and the crystalline externides (Reading Prong, Blue Ridge belt, and Piedmont province). Long, thrust-cored anticlines predominate in the sedimentary externides. A widespread layer-parallel shortening preceded the folding; it is largely coaxial with the folding but extends considerably farther to the northwest toward the craton. It is hypothesized that the folding developed in reverse order, sequentially from the northwest to the southeast. The crystalline externides are dominated by low-angle thrust faults and upright folds trending east-northeast. The first-order Valley and Ridge folds on the northwest side acted as a buttress and diverted the crystalline externides rocks north-northwestwardly, onto the topographic low area over the Anthracite region. This thrusting of the crystalline externides caused anthracitization of the coals within the Pennsylvanian rocks there. Metamorphism and magmatism were significant events during the earlier phase of the Alleghany orogeny in the southern Appalachians. Whatever magmatism and medium-to high-grade metamorphism developed in the north-central Appalachians are in the covered internides to the southeast. The Alleghany orogeny of the north-central Appalachians occurred during the Early Permian. Erosion of anticlinal crests probably began as the folds grew, with accumulation of this locally-derived sediment in the intervening synclines. A regional alluvial plain coalesced above the partially-eroded externides structures as erosion of the pre-Alleghany highland and the Alleghany hinterland mountains continued to the southeast, spreading sediment to the northwest. This erosion and northwest transport probably persisted, with diminishing intensity, throughout the remainder of the Permian and into the Mesozoic, and changed only with the beginning of crustal extension during the Late Triassic.
American Journal of Science↗
Oviduct modifications in foam-nesting frogs, with emphasis on the genus Leptodactylus (Amphibia, Leptodactylidae)
Various species of frogs produce foam nests that hold their eggs during development. We examined the external morphology and histology of structures associated with foam nest production in frogs of the genus Leptodactylus and a few other taxa. We found that the posterior convolutions of the oviducts in all mature female foam-nesting frogs that we examined were enlarged and compressed into globular structures. This organ-like portion of the oviduct has been called a “foam gland” and these structures almost certainly produce the secretion that is beaten by rhythmic limb movements into foam that forms the nest. However, the label “foam gland” is a misnomer because the structures are simply enlarged and tightly folded regions of the pars convoluta of the oviduct, rather than a separate structure; we suggest the name pars convoluta dilata (PCD) for this feature. Although all the foam-nesters we examined had a pars convoluta dilata , its size and shape showed considerable interspecific variation. Some of this variation likely reflects differences in the breeding behaviors among species and in the size, type, and placement of their foam nests. Other variation, particularly in size, may be associated with the physiological periodicity and reproductive state of the female, her age, and/or the number of times she has laid eggs.
South American Journal of Herpetology↗
Distinguishing native (Celastrus scandens L.) and invasive (C. orbiculatus Thunb.) bittersweet species using morphological characteristics
Celastrus orbiculatus is an invasive liana in the Eastern United States. Its native congener, C. scandens , is less common and declining in the Northeast. The correct identification of these two species is often difficult because of their similar vegetative characteristics. Using morphological characteristics of both species growing naturally along a sand dune/forest ecotone, we built models for use in discriminating between the species, given a suite of leaf and fruit traits. We confirmed that the two species can be discriminated effectively using fruit characters, notably fruit volume and seed number. Several leaf traits, such as length-to-width ratio and leaf apex length can also discriminate between the species, but without the same predictive reliability of fruit traits. In addition, we determined that at leaf out in the spring the leaves of the two species were folded differently in the bud allowing them to be successfully discriminated in the early spring. Land managers could use this information to differentiate between the two species in the field and thereby control for the invasive C. orbiculatus , while preserving remaining populations of C. scandens .
Journal of the Torrey Botanical Society↗
Groundlayer vegetation gradients across oak woodland canopy gaps
Frequency of groundlayer plants was measured across oak woodland canopy gaps at three sites in northwest Indiana to examine how vegetation varied with gap size, direction along the gap edge, and microhabitat. Microhabitats were defined as under the canopy adjacent to the gap, along the gap edge, and within the gap. Gap-sites consisted of gaps plus adjacent tree canopy. Gaps were classified as small (16 ± 1 m 2 ), medium (97 ± 8), and large (310 ± 32). Neither richness nor diversity differed among microhabitats, gap sizes, or edges. Similarity between microhabitats wthin a gap-site increased as the distance between plots decreased and as the difference in PAR decreased, the latter explaining twice the variation in percent dissimilarity compared to Mg concentration, A horizon depth, and litter cover. Diervilla lonicera , Frageria virginiana , Helianthus divaricatus , Polygonatum pubescens , Quercus velutina , Smilacena stellata , and Tradescantia ohiensis decreased, while Tephrosia virginiana and legumes increased in frequency, from canopy to gap, and C 4 grasses peaked at the gap edge, independent of gap size. Additional species frequency varied across the microhabitat gradient within specific sites. Sorghastrum nutans was three times more frequent in gaps at large sites than elsewhere. The vegetation in medium-sized gap-sites was more variable than within small and large gap-sites, suggesting greater environmental heterogeneity at that scale. Within gap-sites, vegetation was more heterogeneous within edges and canopies than in gaps. Edges were more similar in composition to gaps than to canopy groundlayer within gap-sites. Few species varied significantly in frequency around the gap edge. The oak woodland groundlayer on sandy substrates can be characterized as a mosaic of forb dominated vegetation that varies across light gradients associated with canopy gaps, transitioning to islands of grassland vegetation when gaps exceed 160 m 2 .
Journal of the Torrey Botanical Society↗
Daily survival rate and nest-site selection of Zone-tailed Hawks (Buteo albonotatus) in the Chihuahuan Desert ecoregion of Texas
The Zone-tailed Hawk ( Buteo albonotatus ) is one of the least studied raptors in North America and lacks contemporary literature allowing informed management decisions for this species. Zone-tailed Hawks occupy rugged areas in the southwestern region of the United States and are listed as state threatened in Texas. Our objectives were to assess habitat, productivity, and daily survival rate (DSR) of Zone-tailed Hawk nests in riparian zones of the Chihuahuan Desert Ecoregion of Texas. We surveyed for Zone-tailed Hawk nests along ∼30 km of 12 riparian corridors in Brewster, Jeff Davis, and Presidio Counties, Texas. We monitored 11 and 15 Zone-tailed Hawk nests in 2018 and 2019, respectively, and conducted vegetation surveys at the nest tree, nest site (11.3-m radius), and paired random locations. We used nest survival modeling to evaluate the effects of eight habitat variables (nest tree diameter at breast height [DBH], nest tree height, nest height, nest distance to main stem, nest to tree height ratio, mean stand height, number of trees within nest site, and mean nest site DBH) on nest DSR. DSR was positively correlated with nest to tree height ratio and nest tree DBH. Zone-tailed Hawk nests had an estimated 0.991 (standard error [SE] = 0.004, 95% CI = 0.980–0.996) constant DSR and ultimately a 51.4% chance of nest success (SE = 0.0943) across the nesting season. Our results suggest that by selecting larger trees for nesting as well as placing nests higher within the tree, Zone-tailed Hawks may increase their chances of successfully fledging young.
Texas↗
Conservation value of Mount Rushmore National Memorial's forest
Justifying the maintenance of small natural areas requires understanding their contribution to the conservation of specific natural resources. Mount Rushmore National Memorial (MORU) is a small portion of the Black Hills of western South Dakota and eastern Wyoming. Because it has been protected from logging since the late 1930s, it may serve as an important part of the Black Hills forest as a whole. To understand this role, we investigated the extent and degree of logging activities in the memorial and compared the current structure of the MORU forest to that in the rest of the Black Hills today and before Euro-American settlement. Our results suggest that approximately 29% of the park has had no tree harvesting activity, 18% of the park has had only selective cutting of trees, and 66% (344 ha) of the park's area is covered by old-growth forest. Based on current estimates of similar forest in the remainder of the Black Hills, the forest at MORU constitutes the second-largest area of old-growth ponderosa pine forest in the Black Hills. Although the current structure of the forest does not appear to be outside the range of natural variability for this ecosystem, some components of the forest are near the edge of this range. Conservation of this important natural resource will most likely require more active management than has occurred in the past, but this management will require careful consideration because of the rarity of this resource in the region.
Natural Areas Journal↗
Implications of black-tailed prairie dog spatial dynamics to black-footed ferrets
The spatial dynamics of black-tailed prairie dog (Cynomys ludovicianus) colonies affect the utility of these environments for other wildlife, including the endangered black-footed ferret (Mustela nigripes). We used location data of active and inactive black-tailed prairie dog burrows to investigate colony structure, spatial distribution, and patch dynamics of two colonies at ferret recovery sites. We used kernel-based utilization distributions (UDs) of active and inactive burrows from two time periods (six and 11 years apart) as the basis for our analysis. Overall, the total extent of our prairie dog colonies changed little over time. However, within colonies, areas with high densities of active and inactive prairie dog burrows formed patches and the distribution of these patches changed in size, shape, and connectivity over time. At the Conata Basin site, high-density active burrow patches increased in total area covered while decreasing in connectivity as they shifted towards the perimeter of the colony over time. At the UL Bend site, we observed a similar but less pronounced shift over a longer period of time. At both sites, while at a large scale it appeared that prairie dogs were simply shifting areas of activity towards the perimeter of colonies and abandoning the center of colonies, we observed a dynamic interaction between areas of active and inactive burrows within colonies over time. Areas that previously contained inactive burrows tended to become active, and vice versa, leading us to hypothesize that there are shifts of activity areas within colonies over time as dictated by forage availability. The spatial dynamics we observed have important implications for techniques to estimate the suitability of ferret habitat and for the management of prairie dog colonies. First, fine-scale techniques for measuring prairie dog colonies that account for their patchy spatial distribution are needed to better assess ferret habitat suitability. Second, the shift of high-density areas of active prairie dog burrows, likely associated with changes in vegetation, suggests that through the management of vegetation we might be able to indirectly improve habitat for ferrets. Finally, we found that prairie dog distributions within a colony are a naturally dynamic process and that management strategies should consider the long-term value of both active and inactive areas within colonies.
Natural Areas Journal↗
Health benefits of geologic materials and geologic processes
The reemerging field of Medical Geology is concerned with the impacts of geologic materials and geologic processes on animal and human health. Most medical geology research has been focused on health problems caused by excess or deficiency of trace elements, exposure to ambient dust, and on other geologically related health problems or health problems for which geoscience tools, techniques, or databases could be applied. Little, if any, attention has been focused on the beneficial health effects of rocks, minerals, and geologic processes. These beneficial effects may have been recognized as long as two million years ago and include emotional, mental, and physical health benefits. Some of the earliest known medicines were derived from rocks and minerals. For thousands of years various clays have been used as an antidote for poisons. “Terra sigillata,” still in use today, may have been the first patented medicine. Many trace elements, rocks, and minerals are used today in a wide variety of pharmaceuticals and health care products. There is also a segment of society that believes in the curative and preventative properties of crystals (talismans and amulets). Metals and trace elements are being used in some of today’s most sophisticated medical applications. Other recent examples of beneficial effects of geologic materials and processes include epidemiological studies in Japan that have identified a wide range of health problems (such as muscle and joint pain, hemorrhoids, burns, gout, etc.) that may be treated by one or more of nine chemically distinct types of hot springs, and a study in China indicating that residential coal combustion may be mobilizing sufficient iodine to prevent iodine deficiency disease.
International Journal of Environmental Research an↗
Comparison of physical to numerical mixing with different tracer advection schemes in estuarine environments
The numerical simulation of estuarine dynamics requires accurate prediction for the transport of tracers such as temperature and salinity. During the simulation of these processes, all numerical models introduce two kinds of tracer mixing: 1) by parameterizing the tracer eddy diffusivity through turbulence models leading to a source of physical mixing and 2) discretization of the tracer advection term that leads to numerical mixing. Both physical and numerical mixing vary with the choice of horizontal advection schemes, grid resolution, and time step. By simulating four idealized cases, this study compares physical and numerical mixing for three different tracer advection schemes. Idealized domains involving only physical and numerical mixing are used to verify the implementation of mixing terms by equating them to total tracer variance. Among the three horizontal advection schemes, the scheme that causes the least numerical mixing while maintaining a sharp front also results in larger physical mixing. Instantaneous spatial comparison of mixing components shows that physical mixing is dominant in regions of large vertical gradients while numerical mixing dominates at sharp fronts that contain large horizontal tracer gradients. In the case of estuaries, numerical mixing may dominate locally over physical mixing; however, the amount of volume integrated numerical mixing through the domain compared to integrated physical mixing remains relatively small for this particular modeling system.
Journal of Marine Science and Engineering↗
Are Mojave Desert annual species equal? Resource acquisition and allocation for the invasive grass Bromus madritensis subsp. rubens (Poaceae) and two native species
Abundance of invasive plants is often attributed to their ability ot outcompete native species. We compared resource acquisition and allocation of the invasive annual grass Bromus madritensis subsp. rubens with that of two native Mojave Desert annuals, Vulpia octoflora and Descurainia pinnata , in a glasshouse experiment. Each species was grown in monoculture at two densities and two levels of N availability to compare how these annuals capture resources and to understand their relative sensitivities to environmental change. During >4 mo of growth, Bromus used water more rapidly and had greater biomass and N content than the natives, partly because of its greater root‐surface area and its exploitation of deep soils. Bromus also had greater N uptake, net assimilation and transpiration rates, and canopy area than Vulpia . Resource use by Bromus was less sensitive to changes in N availability or density than were the natives. The two native species in this study produced numerous small seeds that tended to remain dormant, thus ensuring escape of offspring from unfavorable germination conditions; Bromus produced fewer but larger seeds that readily germinated. Collectively, these traits give Bromus the potential to rapidly establish in diverse habitats of the Mojave Desert, thereby gaining an advantage over coexisting native species.
California, Nevada↗
Using thermal infrared cameras to detect avian chicks at various distances and vegetative coverages
Population monitoring of nesting waterbirds often involves frequent entries into the colony, but alternative methods such as local remotely sensed thermal imaging may help reduce disturbance while providing a cost-effective way to survey breeding populations. Such an approach can have high initial costs, however, which may have reduced the number of studies investigating functionality of paired thermal infrared camera and small unmanned aerial systems. Here, we take the first step of exploring the ability of two thermal infrared cameras to detect an avian chick under varying vegetative cover and distances, preceding field-mounting applications on a small unmanned aerial system. We created seven “bioboxes” to simulate a range of natural vegetation types and densities for a globally important colonial ground-nesting waterbird species, the common tern Sterna hirundo . We placed a juvenile chicken Gallus gallus (surrogate for the locally endangered common tern) in each box, and we tested two market-accessible infrared cameras (produced by FLIR Systems and Infrared Cameras, Inc.) at five elevations using a stationary boom (maximum height = 12 m). We applied computer-based digital thresholding to collected images, identifying pixels meeting one of seven threshold values. The chick was visible from at least one threshold value in 19 and 31 of 35 processed by the FLIR Systems and Infrared Cameras, respectively. Percentage of the chick identified across thresholds was generally highest at lower threshold values and elevations and decreased as elevation and threshold increased; however, the relative importance of each variable changed dramatically across bioboxes and camera types. Ability to detect a chick from processed images generally decreased with increasing elevation, and although we made no quantitative comparisons among boxes, detectability appeared greatest in images from both cameras when little or no vegetation was present. Interestingly, no single threshold value was best for all bioboxes. We observed notable differences between cameras including visual resolution of detected temperature differentials and image processing speed. Results of this controlled study show promise for the use of thermal infrared systems for detecting cryptic species in vegetation. Future research should work to combine thermal infrared and visual sensors with small unmanned aerial systems to test applicability in a mobile field application.
Journal of Fish and Wildlife Management↗
Estimating bird damage from damage incidence in wine grape vineyards
Bird damage was measured during 1977 and 1978 at 32 wine grape vineyards in the San Joaquin Valley and North Coastal Region of California. Both the percentage bird loss (PBL) and the percentage of bunches damaged (BDI = bird damage incidence) were determined during 55 total-damage assessments, and the resulting data pairs were used to develop a regression of PBL on BDI. The final prediction equation was loge (PBL + 1) = 0.0385 BDI, for which the SE = 9.6297 10-4, and it accounted for 97% of the observed variation. We conclude that by using that equation, reasonably accurate predictions of PBL can be obtained from relatively quick and inexpensive estimates of BDI. Guidelines for the use of the prediction method and the accuracy of some PBL predictions are discussed.
American Journal of Enology and Viticulture↗
Blastomycosis in wild wolves
Blastomycosis was fatal to a wild wolf in Minnesota, and serologic evidence of blastomycosis was found in a Wisconsin wolf. No unusual movements were detected in the Minnesota animal from October 1983 through October 1985. However, by early December 1985, this wolf was weak and debilitated, and it perished on 14 December after approaching a human residence.
Minnesota, Wisconsin↗
A cryopreservation method for Pasteurella multocida from wetland samples
A cryopreservation method and improved isolation techniques for detection of Pasteurella multocida from wetland samples were developed. Wetland water samples were collected in the field, diluted in dimethyl sulfoxide (DMSO, final concentration 10%), and frozen at -180 C in a liquid nitrogen vapor shipper. Frozen samples were transported to the laboratory where they were subsequently thawed and processed in Pasteurella multocida selective broth (PMSB) to isolate P. multocida. This method allowed for consistent isolation of 2 to 18 organisms/ml from water seeded with known concentrations of P. multocida. The method compared favorably with the standard mouse inoculation method and allowed for preservation of the samples until they could be processed in the laboratory.
California, Nebraska, Nevada↗