2,836 research outputs found
Best practices for HPM-assisted performance engineering on modern multicore processors
Many tools and libraries employ hardware performance monitoring (HPM) on
modern processors, and using this data for performance assessment and as a
starting point for code optimizations is very popular. However, such data is
only useful if it is interpreted with care, and if the right metrics are chosen
for the right purpose. We demonstrate the sensible use of hardware performance
counters in the context of a structured performance engineering approach for
applications in computational science. Typical performance patterns and their
respective metric signatures are defined, and some of them are illustrated
using case studies. Although these generic concepts do not depend on specific
tools or environments, we restrict ourselves to modern x86-based multicore
processors and use the likwid-perfctr tool under the Linux OS.Comment: 10 pages, 2 figure
Southeast Florida Shallow-Water Habitat Mapping & Coral Reef Community Characterization
Baseline mapping and quantitative assessment data are required prior to future permitted or un-permitted impacts in order to determine the pre-existing state of the benthic resources; therefore, it is imperative that these data be collected on the ecologically sensitive and economically valuable shallow-water coral reef habitats in southeast Florida. In southeast Florida, the nearshore reef habitats are most vulnerable to coastal construction activities and other anthropogenic impacts, therefore these habitats were the focus for this study. The study goals were to provide a spatially appropriate map of increased resolution and a regional quantitative characterization of nearshore benthic resources to evaluate differences in benthic communities between habitats and with latitude for the southeast Florida region of the Florida Reef Tract. This study is a snapshot habitat characterization providing the current status of shallow-water coral reef community composition. Additionally, these data can be used to reduce un-permitted impacts by informing marine zoning efforts and aid in the creation of new no-anchor zones.
Detailed 1ft resolution overlapping aerial photographs were collected for the Nearshore Ridge Complex (NRC) and Inner Reef from Key Biscayne to Hillsboro Inlet, 68.5km of coastline by PhotoScience, Inc. on March 8, 2013. The imagery and recent bathymetry were visually interpreted into benthic habitat maps. Quantitative groundtruthing of 265 targeted and randomized sites was conducted between April and June 2014. Five 1km wide cross-shelf corridors were placed as evenly as possible across the mapped space while maintaining consistent habitat types and amounts between corridors and avoiding any major anthropogenic influences like shipping channels and proximity to inlets and outfalls. Survey site locations were stratified across three main habitats within each corridor: Colonized Pavement-Shallow, Ridge-Shallow, and Linear Reef-Inner. Percent cover data at each site was collected. Additionally, species, colony size (length, width, height), percent mortality, condition (pale or bleached), and presence of disease was recorded for stony corals. Gorgonians were categorized by morphology (rod, plume, fan) and counted in four size classes (4-10, 11-25, 26-50, and \u3e50cm). Xestospongia muta and Cliona spp. were also counted. Then an accuracy assessment was performed where drop camera video with GPS data were collected at 494 locations randomly stratified across all habitat types. The overall accuracy was 97.9% at the Major Habitat level.
Of the 172.73km² seafloor mapped, the polygon totals indicated 41.34% was Sand, 47.07% was Coral Reef and Colonized Pavement, 9.35% was Seagrass, and 2.25% was Other Delineations. These totals are estimates due to some habitats having a large mix of sand within. Three habitat types dominated the mapped hardbottom area. The largest was Colonized Pavement (38.36km²), followed by Ridge-Shallow (25.52km²), and Linear Reef-Inner (14.99km²). These comprised 97% of the hardbottom habitats. Seagrass accounted for 9.35% of the map and was solely contained south of Government Cut. Sand comprised 41.34% of the map and Other Delineations accounted for 2.25%.
The clear, high-resolution images enabled the delineation of thirty-five dense Acropora cervicornis patches. Some of these corresponded to known locations of dense patches. These are the largest dense patches in the continental United States. Using aerial photography delineations area estimates, the seven patches near the known existing locations totaled approximately 46,000m² whereas the 28 newly confirmed areas exceed 110,000m². Dense Acropora cervicornis comprised 1% of the mapped hardbottom habitats.
Significant differences in percent benthic cover between habitats occurred in all corridors, however some comparisons were stronger than others. Corridor 1 exhibited clear differences between the colonized pavement and inner reef sites due to the high percentages of seagrass on the colonized pavement that did not occur on the Inner Reef sites (nor any other habitat in the region). Corridor 2 showed much weaker differences between habitat types, however the colonized pavement sites were significantly distinct from the inner reef and ridge sites due to the comparatively high percentage of sand on the colonized pavement versus the inner reef and ridge. Corridor 3 ridge was significantly distinct from the colonized pavement and inner reef sites mostly due to lower percentage of Palythoa spp. on the ridge. Corridor 4 inner reef sites were significantly different from the others driven by much higher percentage of macroalgae and higher Palythoa spp. Corridor 5 exhibited significant differences between all habitat types. Inner reef sites had higher percentages of Palythoa spp., gorgonians, and sponges than any other habitat. Colonized pavement sites had the lowest percentages of gorgonians and Palythoa spp. while having the highest percentages of sand.
Comparisons of benthic cover percentages between all sites in a given habitat type were conducted to evaluate latitudinal community differences. Among colonized pavement sites, Corridor 1 was significantly different from all other corridors due to the presence of seagrass which only occurred in Corridor 1 colonized pavement. Corridor 5 was also significantly distinct from all other corridors due to a low percentage of gorgonians, stony corals, and Palythoa spp. with a high percentage of turf algae. The ridge sites comparisons showed distinct clustering of corridors 2, 3, and 5 in the MDS indicating that there are latitudinal differences in benthic cover in the ridge habitat. The main dissimilarity contributors in corridor 2 were lower percentages of palythoa spp. and macroalgae than corridors 3 and 5 and higher percentages of gorgonians and stony corals than corridor 5. Corridor 3 had higher percentages of macroalgae, stony corals, and gorgonians than corridor 5. The inner reef sites also exhibited latitudinal differences in benthic cover. Corridors 1 and 5 separated out from the other corridors and each other. The main cover classes driving the clustering of corridor 1 sites were high percentages of gorgonians and Palythoa spp, while the main contributor to the corridor 4 cluster was high macroalgae percentages in that corridor.
A total of 4,568 stony coral colonies were identified, counted, and measured. Twenty-two species were found, but Porites astreoides (29.7%), Siderastrea siderea (17.5%), and Acropora cervicornis (10.3%) comprised 57.5% of the total number of stony corals measured in this study. The largest coral measured in the study was a Siderastrea siderea located in corridor 4 which measured 225 cm long, 200 cm wide, 140 cm tall and an estimated 4.1 m² of live tissue. Stony coral density pooled for the entire surveyed area of 4,200m² was 1.09 corals/m². Mean coral density was lowest in the colonized pavement sites and highest in the inner reef sites, however this also varied by corridor. The colonized pavement coral density in Corridors 1 and 5 was lowest and highest in Corridors 3 and 4.
Coral density on ridge habitat had a similar pattern to colonized pavement with corridor 3 having the highest density. Conversely coral density on the inner reef was highest in corridor 1 and corridor 4. Acropora cervicornis was found in higher densities than S. siderea on the colonized pavement but it only occurred in corridors 3 and 4. It was also found in higher density on ridge habitat except for corridor 5. Of the 471 A. cervicornis colonies counted, only 5.3% occurred on the inner reef. Two hundred and thirty-five (49.9%) were found in the colonized pavement and 211 (44.8%) at the ridge sites.
The mean number of coral species (richness) varied by corridor and habitat. Colonized pavement sites had the lowest richness and it was highest on inner reef. Mean richness also varied by corridor within habitats. Among the colonized pavement sites, corridor 3 and corridor 4 had the highest mean richness and corridor 5 the lowest. Similarly, among the ridge site, mean coral richness was highest in corridor 3 and lowest in corridor 5. Mean richness among inner reef sites were not very different however corridor 1 was significantly higher than corridor 3.
A total of 30,076 gorgonians were counted, classified by morpho-type (Fan, Plume, Rod), and binned into size classes. Rods were the most abundant comprising almost 72% of the total number counted and plumes were second-most comprising 24% of the total. This varied by corridor and habitat. With all size classes combined, fans were lowest on the colonized pavement and highest on the ridge. Plumes were higher on the inner reef than the colonized pavement and ridge. Conversely rods were lower on the inner reef than the colonized pavement and ridge. Gorgonians also varied within habitat types by corridor. In colonized pavement, fans were highest in corridors 3 and 4 whereas plumes were more abundant in the southern corridors. Rods were dominantly abundant throughout the colonized pavement except for corridor 5 where they were conspicuously absent. In the ridge habitat, fans varied among corridors without a clear latitudinal pattern. Plumes were more abundant in the southern corridors, while rods were dominantly abundant throughout. The inner reef habitats generally had a higher abundance of plumes and a more even ratio of rod and plume abundance throughout all corridors. Plumes were the most abundant type in corridor 1, but were also high in corridors 3 and 5.
Xestospongia muta colonies were predominantly found at the inner reef sites. Of the 262 total colonies counted, 87.7% were at inner reef sites. Densities were lower than gorgonians and stony corals throughout the study. Mean X. muta abundance varied between corridors. In colonized pavement and ridge habitats, X. muta predominantly occurred on corridor 4 however mean abundance was very low. At the inner reef sites, X. muta was much lower in corridor 1 than all other corridors, which did not significantly vary.
This study elucidated new data on the extent of the Endangered Species Act threatened coral species, Acropora cervicornis. Only approximately 30% of the discovered dense patches were identified as previously known and the total regional area of A. cervicornisdense patches is now estimated at 156,000 m². The condition of the coral in these patches cannot be surmised from the images. Additionally, the polygons depicted in the habitat map are likely under-representative of the shape and sizes of these patches due to their fuzzy boundaries. A detailed study to map their boundaries and characterize their condition is needed to properly inventory these patches and their condition. Furthermore, the only way to fully understand if the net amount is increasing is to investigate it on a regional level. Previous imagery must be identified and used to determine the timing of when these patches came into existence. Unfortunately no consistent data sets have been identified that can be used for this purpose at this time. A compilation of local imagery has been helpful in some cases. It is recommended that a regional set of imagery be repeatedly collected in the future to elucidate the dynamics of dense patches of A. cervicornis and document the current extent of nearshore resources. This is especially important after large storm events.
This study has expanded the present knowledge on the amount, location, and species type of ecologically important large coral colonies. Although smaller than the minimum mapping unit for this study (and thus not in this study’s scope and funded separately), 187 blips in the LIDAR associated with dark specs in the imagery were identified and a portion investigated. Of the 53 that were visited, 47 were stony corals estimated between 2 and 5 m in diameter. Twenty-three (43%) were alive in various conditions. These were predominantly Orbicella faveolata (20), but 2 were Siderastrea siderea and one was a Montastrea cavernosa. Corals of this size are likely to be hundreds of years old, meaning they have persisted through the multitude of anthropogenic impacts that have occurred in the region. Large coral colonies are more fecund, giving an exponentially increased amount of reproductive output making these colonies particularly important in the restoration of the reef system. It is recommended that a host of important studies be conducted to understand the full extent, size, condition of these large, resilient corals and to monitor them through time, investigate their reproduction and genetic diversity, and perhaps use them to help propagate naturally resilient corals in restoration efforts
Southeast Florida Large Coral Assessment 2015
The 2013 nearshore mapping project conducted by Walker and Klug expanded the previous knowledge on the amount, location, and species type of ecologically important large (\u3e2 m) coral colonies in southeast Florida. They discovered over 110 previously undocumented large corals of which 60 were dead and 50 were still alive; 40 of the living corals were larger than 2 m wide and up to 5 m in diameter. Because these corals are the largest and oldest organisms on our reefs, they deserve special attention.
Currently there is unprecedented disease and bleaching in the northern portion of the Florida Reef Tract. It is imperative that the large coral baseline condition is documented to understand the present condition of the large corals in southeast Florida. Understanding how the coral populations are affected by this outbreak and identifying which individuals were resilient enough to recover is critical to the management of the SE FL coral reef ecosystem therefore the objective of this project was to achieve recommendation four from Walker and Klug (2014): conduct a full inventory study to understand the extent, size, condition of the large (\u3e 2 m diameter) corals.
Live corals greater than 2 m diameter identified during reconnaissance were assessed by SCUBA divers. High resolution photographs and video were collected of the coral as a permanent record of its condition. Photographs were taken systematically at each of the four main compass headings (north, east, south, and west) and from overhead. In cases where the coral was too large or the visibility was poor, multiple pictures of the coral were taken at a closer distance. Divers then estimated the percent live tissue cover and percent recent and old dead skeleton remaining, percentage of bleached tissue, percentage of diseased tissue, and the number of tissue isolates. Each coral was then measured using a rigid meter stick was used to measure height, the linear distance along the longest axis, and the widest axis perpendicular to the first axis and a measuring tape to measure the distance over the surface of the coral. In areas with multiple large corals, a Garmin 76csx GPS in an underwater housing with a floating antenna was used to collect the coordinate of each coral.
Surveys were conducted over eleven days between September and November 2015. Additional reconnaissance surveys were conducted to assess sixty-two new targets that were not previously visited due to poor visibility during Government Cut channel dredging. A total of 115 corals were inventoried and measured. See Appendix 1 for images and data collected on each coral. The majority of corals were Orbicella faveolata (78.2%), followed by Montastrea cavernosa, Siderastrea siderea, Colpophyllia natans, Orbicella annularis, and Pseudodiploria strigosa. Corals were found between 4.6 m and 8.8 m depth predominantly in the nearshore colonized pavement and shallow ridge habitats at an average depth of 6.4 m. Colonies were evenly distributed between Miami-Broward and Biscayne Coral Reef Ecosystem Regions. A few corals were spread out but most were clustered into smaller areas.
There was no apparent pattern of size with latitude. Eight corals, all O. faveolata, were measured larger than 4 m and spanned from Key Biscayne to Hollywood. The two largest corals, which measured 5.6 m long, were located off Key Biscayne and contained 50% and 70% live tissue. One other coral measured 5.1 m long located near Bal Harbor and had 30% live tissue.
Almost half of all large corals did not show signs of stress from bleaching or disease, however all of the M. cavernosa, O. annularis, and C. natans had either or both conditions. Thirty-seven percent of all corals had some recent mortality, including all four O. annularis and C. natans colonies and about half of the M. cavernosa, S. siderea, and P. strigosa colonies. Twenty-three percent of all corals had some bleaching, but M. cavernosa appeared to be affected more than other species. There were many smaller M. cavernosa colonies not captured in this study with extensive bleaching, especially in the Biscayne region. Eight percent of all colonies had both bleaching and disease.
The diseases visually observed in this study were white plague, black band, dark spot and possibly Caribbean yellow band. Coral diseases are very difficult to identify precisely in the field and require histological and genetic analyses to be conducted.
Changes in condition were noted between the reconnaissance and the surveys. In 2015, bleaching recovery was noted within 41 days on recently surveyed corals near Key Biscayne. This coincided with a period of noticeable cooler water temperatures and is likely indicative that the 2015 bleaching event was subsiding accordingly. Conversely, the halting of disease progression was not noted in our surveys. For example white plague disease on a C. natans had killed significant tissue over 27 days. The condition and fate of that colony is presently unknown.
Changes in coral condition and live tissue cover were noted between 2014 and 2015. In 2015 corals were found completely bleached that were not bleached in 2014. Colonies were also found fully and partially bleached in 2014 and 2015 where portions of the partially bleached areas were bleached in both years and portions were not. The timing of these changes is worth noting because in south Florida corals usually bleach from heat stress later in the summer around August and September. Corals originally surveyed in June 2014 may have still bleached in 2014, recovered, and bleached again in 2015. Without regular monitoring this cannot be determined.
Disease was not noted to occur in corals between years through our initial photo and video documentation evaluations but it was observed in 2015 when not present in 2014.
Percent mortality was high in all corals combined. When including all of the dead corals found in the reconnaissance, 100% mortality was the highest (34%). However the partial mortality percentages were also high with 43% of corals between 25% and 99% partial mortality and 31% at least half dead. Twenty-three percent were less than one quarter dead including 5% that were more than 90% living.
This study documented baseline conditions of the largest and oldest corals of the southeast Florida reefs which are analogous to the “redwoods” of our nearshore community. In southeast FL, corals grow about 1 cm per year. Corals greater than 2 meters in diameter can be hundreds of years old. The largest corals in a population are the oldest and have exponentially more reproductive capacity than smaller ones, making them the most important demographic of their respective species. Their age indicates that they have persisted through the multitude of anthropogenic impacts and stressors that have occurred in the region since the western colonization of Florida. Their size also provides habitat for a diverse and abundant assemblage of fish. A large proportion of the large corals are in the relatively flat, nearshore habitats, and thus provide an oasis for many fish species.
High partial mortality is an indicator of more stressed systems. We found 65% of large corals were either dead or had less than half of their live tissue remaining. The dead ones are difficult to assess as one must collect samples to identify the species and we do not know when they died. This would be valuable information because it would allow us to determine if the frequency of mortality in these corals is increasing through time. In other words conditions are more stressful today causing more frequent mortality. This can be determined by drilling the corals and determining their ages by comparing them to a reference coral.
Assessing these corals through time is important. We can identify which events reduce their tissues, whether they recover from bleaching, the frequency of bleaching and disease for each coral and the total population, and how resilient they are to stress events. The overwhelming majority of these corals were O. faveolata, a reef-building species listed as threatened under the Endangered Species Act. These resilient corals might give clues to the ability of certain corals to recover from adversity and help in the restoration of the species across the reef tract. Further, large coral colonies are more fecund, giving an exponentially increased amount of reproductive output also making these colonies particularly important in the species’ recovery.
A list of recommendations of work critical to the understanding and management of the Southeast Florida coral populations, especially for O. faveolata, which is threatened under the Endangered Species Act includes: (1) Spatial analysis of large coral distribution, (2) Regular assessments of the large live corals, (3) Identifying the dead coral species and timing of death, (4) Histology and reproductive study, (5) Genetic studies, and (6) Restoration
A Rule-Based Approach to Analyzing Database Schema Objects with Datalog
Database schema elements such as tables, views, triggers and functions are
typically defined with many interrelationships. In order to support database
users in understanding a given schema, a rule-based approach for analyzing the
respective dependencies is proposed using Datalog expressions. We show that
many interesting properties of schema elements can be systematically determined
this way. The expressiveness of the proposed analysis is exemplarily shown with
the problem of computing induced functional dependencies for derived relations.
The propagation of functional dependencies plays an important role in data
integration and query optimization but represents an undecidable problem in
general. And yet, our rule-based analysis covers all relational operators as
well as linear recursive expressions in a systematic way showing the depth of
analysis possible by our proposal. The analysis of functional dependencies is
well-integrated in a uniform approach to analyzing dependencies between schema
elements in general.Comment: Pre-proceedings paper presented at the 27th International Symposium
on Logic-Based Program Synthesis and Transformation (LOPSTR 2017), Namur,
Belgium, 10-12 October 2017 (arXiv:1708.07854
Foraging behavior of red-winged blackbirds (\u3ci\u3eAgelaius phoeniceus\u3c/i\u3e) on sunflower (\u3ci\u3eHelianthus annuus\u3c/i\u3e) with varying coverage of anthraquinone-based repellent
Animals attempt to maximize foraging efforts by making strategic foraging decisions. Foraging efforts can be influenced by chemically defended food. Food resources that are chemically defended force foragers to balance the nutritional gain with the toxic costs of foraging on a defended food resource. Chemical defense, in this case sunflower treated with chemical repellent, may be capable of deterring birds from foraging on treated crops. Blackbirds (Icteridae) cause significant damage to sunflower (Helianthus annuus) with damage estimates of $3.5 million annually in the Prairie Pothole Region of North Dakota, the largest sunflower producing state. Chemical repellents may be a cost-effective method for reducing bird damage if application strategies can be optimized for sunflowers. Anthraquinone-based repellents have been shown to reduce feeding on sunflower achenes by more than 80% in lab studies, but results in the field are inconclusive due to application issues where floral components of sunflower result in low repellent contact with achenes. Ground rigs equipped with drop-nozzles have shown promise in depositing repellent directly on the sunflower face but coverage is variable. We propose to evaluate the feeding behavior of red-winged blackbirds (Agelaius phoeniceus) and the efficacy of an anthraquinone-based avian repellent when applied directly to the sunflower face in a lab-based experiment. Our main objectives are to 1) evaluate the coverage needed on the face of the sunflower to establish repellency, 2) evaluate achene removal rates over time to understand time to aversion at varying repellent coverages, and 3) evaluate the feeding behavior and activity budgets of red-winged blackbirds on treated and untreated sunflower. The results of this study will inform repellent coverage needed at the scale of the sunflower plant to deter feeding or alter time budgets of foraging red-winged blackbirds to ultimately reduce sunflower damage
Modelling the atomic structure of very high-density amorphous ice
The structure of very high-density amorphous (VHDA) ice has been modelled by
positionally disordering three crystalline phases, namely ice IV, VI and XII.
These phases were chosen because only they are stable or metastable in the
region of the ice phase diagram where VHDA ice is formed, and their densities
are comparable to that of VHDA ice. An excellent fit to the medium range of the
experimentally observed pair-correlation function g(r) of VHDA ice was obtained
by introducing disorder into the positions of the H2O molecules, as well as
small amounts of molecular rotational disorder, disorder in the O--H bond
lengths and disorder in the H--O--H bond angles. The low-k behaviour of the
experimental structure factor, S(k), is also very well reproduced by this
disordered-crystal model. The fraction of each phase present in the best-fit
disordered model is very close to that observed in the probable crystallization
products of VHDA ice. In particular, only negligible amounts of ice IV are
predicted, in accordance with experimental observation.Comment: 4 pages, 3 figures, 1 table, v2: changes made in response to
referees' comments, the justification for using certain ice phases is
improved, and ice IV is now disordered as wel
Constraints, Histones, and the 30 Nanometer Spiral
We investigate the mechanical stability of a segment of DNA wrapped around a
histone in the nucleosome configuration. The assumption underlying this
investigation is that the proper model for this packaging arrangement is that
of an elastic rod that is free to twist and that writhes subject to mechanical
constraints. We find that the number of constraints required to stabilize the
nuclesome configuration is determined by the length of the segment, the number
of times the DNA wraps around the histone spool, and the specific constraints
utilized. While it can be shown that four constraints suffice, in principle, to
insure stability of the nucleosome, a proper choice must be made to guarantee
the effectiveness of this minimal number. The optimal choice of constraints
appears to bear a relation to the existence of a spiral ridge on the surface of
the histone octamer. The particular configuration that we investigate is
related to the 30 nanometer spiral, a higher-order organization of DNA in
chromatin.Comment: ReVTeX, 15 pages, 18 figure
Ammonoid soft tissue remains revealed by computed tomography
Findings of ammonoid soft tissues are extremely rare compared to the rich fossil record of ammonoid conchs ranging from the Late Devonian to the Cretaceous/Paleogene boundary. Here, we apply the computed-tomography approach to detect ammonoid soft tissue remains in well-preserved fossils from the Early Cretaceous (early Albian) of NE-Germany of Proleymeriella. The ammonites were found in glauconitic–phosphatic sandstone boulders. Analyses of the high-resolution Ct-data revealed the presence of cameral sheets, the siphuncular tube wall, and the siphuncle itself. The siphuncle is a long, segmented soft tissue that begins at the rear end of the body chamber and comprises blood vessels. Chemical analyses using energy-dispersive spectroscopy (EDS) showed that all preserved soft tissues were phosphatized and are now composed of fluorapatite. The same holds true for preserved shell remains that locally show the nacreous microstructure. We provide a short description of these soft tissue remains and briefly discuss the taphonomic pathway.Fil: Hoffmann, R.. Ruhr-Universität Bochum; AlemaniaFil: Moron Alfonso, Daniel Andres. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Klug, C.. Universitat Zurich; SuizaFil: Tanabe, K.. The University Of Tokyo; JapĂł
A Sonic Net reduces damage to sunflower by blackbirds (Icteridae): Implications for broad-scale agriculture and crop establishment
Blackbirds, such as red-winged blackbirds (Agelaius phoeniceus), are notorious agricultural pests and damage crops at multiple stages of growth. Our aim was to test a novel deterrent, the use of sound designed to mask communication among birds (termed a “Sonic Net”), to deter blackbirds (Icteridae) from target areas of maturing sunflower crops. The Sonic Net masks communication of a target species by delivering “pink noise” that overlaps with the frequencies that the species uses for acoustic communication. If birds cannot hear predators or conspecific warning calls their perceived predation risk increases, and they relocate to an area with lower predation risk. Working with local sunflower producers in North Dakota, USA we set up experimental sites in three sunflower fields that were actively used by mixed-species blackbird flocks. In each field, we established two 0.2 ha plots and measured the initial area of damage for 63 individually-marked sunflowers. We applied the Sonic Net treatment to one of the paired plots in each field. At the end of the 20-day treatment period, we measured the total area damaged on the individually-marked sunflowers from each plot to calculate the change in damage for each sunflower. In all three fields, Sonic Net treatments substantially reduced percent damage to sunflowers, by 28.6% (95% CI: 12.5–41.7%), 63.6% (57.2–69.0%) and 22.6% (16.6–28.1%) for fields in Burleigh, McIntosh, and Emmons, respectively. In addition, sunflowers with a higher initial area of available seed experienced higher damage. We predict that the effect of the Sonic Net treatment may be greater in other crop phases and types, such as in the establishment phase or ground cover crops. During crop establishment there is a relative lack of tall, three-dimensional vegetational structure, which would allow for more effective spread of the Sonic Net sound and offer fewer physical refugia for birds to lower their perceived predation risk. We suggest both larger scale agricultural tests of the Sonic Net and efficacy tests for protecting crops at early growth stages to further explore the usefulness of this technology for crop protection
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