Northern Lower Peninsula Of Michigan Research Articles

Accounting for Changes in Radiation Improves the Ability of SIF to Track Water Stress‐Induced Losses in Summer GPP in a Temperate Deciduous Forest

AbstractGlobal observations of solar‐induced chlorophyll fluorescence (SIF) are available from multiple satellite platforms, and SIF is increasingly used as a proxy for photosynthetic activity and ecosystem productivity. Because the relationship between SIF and gross primary productivity (GPP) depends on a variety of factors including ecosystem type and environmental conditions, it is necessary to study SIF observations across various spatiotemporal scales and ecosystems. To explore how SIF signals relate to productivity over a temperate deciduous forest, we deployed a PhotoSpec spectrometer system at the University of Michigan Biological Station AmeriFlux site (US‐UMB) in the northern Lower Peninsula of Michigan during the 2018 and 2019 growing seasons. We found that SIF correlated with GPP across diurnal and seasonal cycles (R2 = 0.61 and 0.64 for 90‐min‐ and daily‐averaged data), but that SIF signals were more strongly related to downwelling radiation than GPP (R2 = 0.91 for daily‐averaged data). The dependence of SIF on radiation obscured the impact of intraseasonal drought in the SIF timeseries, but drought stress was apparent as a decrease in relative SIF, which exhibited a stronger correlation with GPP (R2 = 0.56) than other remotely sensed data over the drought period. These results highlight the potential of SIF for detecting stress‐induced losses in forest productivity. Additionally, we found that the red:far‐red SIF ratio did not exhibit a response to water stress‐induced losses in productivity, but was largely driven by seasonal and interannual changes in canopy structure, as well as by synoptic changes in downwelling radiation.

Evaluating unoccupied aerial vehicles for estimating relative abundance of muskrats

AbstractDue to muskrat (Ondatra zibethicus) population declines in North America, it is important to develop rapid, safe, and economical tools for estimating abundance over large spatial and temporal scales. During November 2020–February 2021, we assessed unoccupied aerial vehicles (UAVs) at Bear Creek Flooding State Wildlife Management Area in the northern Lower Peninsula of Michigan. We examined aerial red‐green‐blue (RGB) and thermal imagery for estimating the total number of muskrat houses during a snow‐free and snow‐cover period relative to ground surveys. Muskrat house counts were similar between the December snow‐cover UAV RGB image survey and February ground survey (V = 70, P = 0.559), but 132% and 136% lower for November snow‐free UAV survey compared to snow‐cover UAV (V = 203.5, P < 0.001) and ground (V = 196, P < 0.001) surveys, respectively. Unoccupied aerial vehicles can rapidly, safely, and economically estimate and track relative abundance of muskrats in wetlands that have some snow cover and should be evaluated further in more systems at different times of the year. Effective use of UAV imaging for muskrat house surveys is dependent on time of day, temperature, and weather conditions. Conducting UAV surveys in tandem with ground surveys would improve estimates of relative abundance if active muskrat houses are better defined.

Forest Disturbance Types and Current Analogs for Historical Disturbance-Independent Forests

Forest classifications by disturbance permit designation of multiple types of both old growth forests and shorter-lived forests, which auto-replace under severe disturbance, and also identification of loss of the disturbance type and associated forest. Historically, fire and flooding disturbance regimes, or conversely, infrequent disturbance, produced unique forests such as disturbance-independent forests of American beech (Fagus grandifolia), eastern hemlock (Tsuga canadensis), and sugar maple (Acer saccharum) in the Eastern United States. However, disturbance has changed to primarily frequent mechanical overstory disturbance, resulting in novel forests. To demonstrate the transition to no-analog forests after disturbance change, I compared historical tree surveys (ca. 1837 to 1857) to current surveys in the Northern Lower Peninsula of Michigan. To establish widespread disturbance change effects, I also located where beech and hemlock are currently most abundant throughout the Eastern US compared to historical distribution of beech–hemlock forests. In the Northern Lower Peninsula of Michigan, beech and hemlock historically were about 30% of all trees, but currently, beech and hemlock are 2% of all trees. Red maple (Acer rubrum) increased from 1% to 11% of all trees and aspen (Populus) increased from 2% to 13% of all trees. The squared-chord difference between historical and current surveys was 0.40, or dissimilar forests. Areas with ≥20% beech and hemlock or ≥15% of either species decreased from about 52 million to 6 million hectares, with current distribution restricted to the Northeastern US. Current forests are dissimilar to historical forests, and this transition appears to be driven by disturbance regimes without historical analogs. Disturbance change may provide perspective in forest management for climate change.

Spatial genetic structure and landscape connectivity in black bears: Investigating the significance of using different land cover datasets and classifications in landscape genetics analyses.

Landscape genetic analyses allow detection of fine‐scale spatial genetic structure (SGS) and quantification of effects of landscape features on gene flow and connectivity. Typically, analyses require generation of resistance surfaces. These surfaces characteristically take the form of a grid with cells that are coded to represent the degree to which landscape or environmental features promote or inhibit animal movement. How accurately resistance surfaces predict association between the landscape and movement is determined in large part by (a) the landscape features used, (b) the resistance values assigned to features, and (c) how accurately resistance surfaces represent landscape permeability. Our objective was to evaluate the performance of resistance surfaces generated using two publicly available land cover datasets that varied in how accurately they represent the actual landscape. We genotyped 365 individuals from a large black bear population (Ursus americanus) in the Northern Lower Peninsula (NLP) of Michigan, USA at 12 microsatellite loci, and evaluated the relationship between gene flow and landscape features using two different land cover datasets. We investigated the relative importance of land cover classification and accuracy on landscape resistance model performance. We detected local spatial genetic structure in Michigan's NLP black bears and found roads and land cover were significantly correlated with genetic distance. We observed similarities in model performance when different land cover datasets were used despite 21% dissimilarity in classification between the two land cover datasets. However, we did find the performance of land cover models to predict genetic distance was dependent on the way the land cover was defined. Models in which land cover was finely defined (i.e., eight land cover classes) outperformed models where land cover was defined more coarsely (i.e., habitat/non‐habitat or forest/non‐forest). Our results show that landscape genetic researchers should carefully consider how land cover classification changes inference in landscape genetic studies.

American black bears and hair snares: a behavioral analysis

Despite the widespread use of noninvasive hair-sampling for American black bear (Ursus americanus) population monitoring, there is no explicit analysis of black bear behavior at hair snare sites. During 2016, we deployed hair snares and camera traps at 40 sites across the northern Lower Peninsula of Michigan, USA, and collected 560 video recordings of black bear activity. Our objectives were to develop an ethogram of bear behaviors at snare sites and quantify their occurrence. We found that bears allocated their time consistently when they were physically inside or outside of the snare, but they divided their time among multiple behaviors when crossing the wire. The inconsistencies in wire crossing revealed unexpected behaviors with important implications for study design. Our findings explicitly describe how black bears interact with hair snares, provide recommendations for addressing the influence of behavior on sampling efficiency, and establish a foundation for further study of animal behavior at hair snares.

Adaptive genetic management: assessing the benefits of translocations

Declines in abundance and genetic diversity in plant and animal populations are increasingly of conservation concern. Genetic rescue, or the supplementation of declining populations with individuals from genetically different sources, may aid in demographic and genetic recovery efforts, assuming introduced individuals successfully reproduce following translocation. However, the relative reproductive contributions of resident and translocated individuals are not frequently evaluated. In the northern lower peninsula of Michigan, USA, fourteen brown trout (Salmo trutta) from each of three different tributaries were introduced into a research stream (Hunt Creek) to supplement a small, isolated resident brown trout population. Mean expected heterozygosity and mean allelic richness differed between the three translocated populations compared to residents. Additionally, inter-population variance in allele frequency (FST) between resident and translocated populations ranged from 0.024 to 0.098. Using genetic parentage assignments, we documented that translocated and resident brown trout did interbreed; however, intra-population mating events were more common. Simulations indicated that increases in genetic diversity among age-1 offspring were the result of reproduction by translocated adults, as genetic variation was significantly above levels expected by reproduction among residents alone (p < 0.001). To achieve management goals for genetic rescue programs, managers would be advised to conduct simulations and hypothesis testing in addition to collection of empirical genetic data to evaluate introduction outcomes.

Spatial Ecology of Re- introduced American Martens in the Northern Lower Peninsula of Michigan

American martens (Martes americana) in the northern Lower Peninsula of Michigan (NLP) represent a re-introduced and isolated population that is the southern-most distributed marten population in eastern North America. During 2005–2006 we conducted a radiotelemetry and track-survey study of martens in the NLP. We estimated home-range size and patterns of habitat use in order to develop a spatial model to predict distribution of marten habitat. Marten home ranges were comprised of more (>75%) upland deciduous and upland mixed forest compared to the landscape, which included ≤60% of these cover types. Within core areas, martens selected upland conifer stands. Our Penrose habitat model identified <25% of the NLP as primary marten habitat. Further, 70% of marten habitat patches were <1000 ha in size and were isolated by an average of 5.3 km (SE = 2.0). Our marten habitat model identifies focal areas for surveying and monitoring populations and sites for supplementation or re-introduction. Our model also highlights the need for managers to better coordinate active landscape-scale management of wildlife and forests to reduce fragmentation impacts on extant and reintroduced marten populations.

The Pivotal Role of Student Labor in the Clarke Historical Library's Moving Image Access and Preservation Project

The Pivotal Role of Student Labor in the Clarke Historical Library's Moving Image Access and Preservation Project Marian J. Matyn (bio) and Tressa Graves (bio) INTRODUCTION TO THE CLARKE, ITS INSTITUTIONAL CONTEXT, AND ITS HOLDINGS The Clarke is both a historical library and archives.1 It is one of the major archives and historical libraries in the state of Michigan and the only one in the northern Lower Peninsula. Its major collecting focus is Michigan history, children's literature, and Central Michigan University (CMU) archives. While the primary-source collections include a wide variety of formats, moving image film constitutes only a small part of the overall collection. Of the nearly 8,000 cubic feet of archival collections in the Clarke stacks, approximately 110 cubic feet are 8mm and 16mm films (450,000 linear feet total). Summary Information on AV Materials in the Clarke Most of the Clarke's films are 16mm acetate film stock, although there is also a small number of 8mm films. The majority of the Clarke's film materials are a part of the Channel 9 & 10 News Collection, 1950s–1980s. Channel 9 & 10 was and remains the main TV news station for the thirty-five counties in the northern Lower Peninsula of Michigan, the entire Upper Peninsula, and parts of Canada. The initial estimate was that the Channel 9 & 10 Collection totaled approximately three thousand reels of film shelved in seventy cubic feet of archival shelving in variously sized containers. These films are the only extant copies of the station's news production from the period. Other films in the Clarke's collection, mostly with a Michigan or CMU focus, are distributed throughout numerous paper-based archival collections and total an additional 20,500 linear feet. [End Page 27] Identification of Significant Subsections of the AV Collection and Their Challenges The main issues faced are lack of description, lack of donor forms, and some level of physical deterioration. No particular series or subseries is in worse condition than another. One CMU film, Football Scrimmage (September 1950), has significant acetate decay and a strong vinegar odor. Seventeen reels of the Channel 9 & 10 News Collection are fused together in a solid mass, an issue known as blocking, thus leaving the films unviewable and unidentifiable. Several Channel 9 & 10 News clips have color dye fading and are now magenta hued. The Clarke has inadequate funds for conservation or digitization of these few films that are badly deteriorated. In the case of Football Scrimmage, it is possible that we will be able to find a CMU alum who will be willing to pay for digitization of the film. Not knowing what is on the blocked films makes it hard to find donors. Many small manuscript-focused archives with film collections are unaware that the International Federation of Film Archives (FIAF) exists and is willing to help them locate other archives better able to care for their film.2 Staff Context of the Archives and Identification of the Authors/Project Leaders The Clarke has six full-time staff members and student employees, none of whom is trained or educated in film access and preservation. Until 2011, archivist Marian Matyn was a lone arranger archivist. Although there are now two archivists, moving images are not part of the newer archivist's responsibility. Matyn and undergraduate student Tressa Graves began the project in 2012 to identify, rehouse, preserve, and make accessible the archival film collections. Neither Matyn nor Graves was a film specialist when the project began, although Graves had interned during summer 2012 at the Alaska Film Archives at the University of Alaska Fairbanks. When planning the project, Matyn and Graves lacked established backgrounds, education, and extensive experience with film. Prior to the film preservation and access project, only very basic archival housing and description were completed for films. Significantly, the Clarke is the first university archives in Michigan to embark on a film access and preservation project. The Henry Ford, located 152 miles southeast of CMU, was the first Michigan cultural heritage institution to initiate a film preservation project. The Clarke was the second institution in the state to do so, closely followed by Michigan State University (MSU...

Home Range and Habitat Use of Female White-Tailed Deer (Odocoileus virginianus) in the Northern Lower Peninsula of Michigan

Because knowledge of home range dynamics and habitat selection is lacking for whitetailed deer (Odocoileus virginianus) in the northern lower peninsula of Michigan, we radiomarked 89 female deer and studied these aspects of their biology during 2005–2008. Mean (± SE) size of annual home ranges and core areas (n = 89) were 2.3 ± 0.1 km2 and 0.5 ± 0.2 km2, respectively, and somewhat smaller than in other northern deer populations. Mean home-range and core-area sizes for the springsummer period (n = 87) were 1.9 ± 0.1 km2 and 0.4 ± 0.1 km2, respectively. Mean home-range and core-area sizes for the fall-winter period (n = 29) were 2.1 ± 0.2 km2 and 0.5 ± 0.1 km2, respectively. Neither home-range nor core-area sizes differed seasonally (P > 0.135), and seasonal home ranges were comparable in size to other northern deer populations. Cover-type use did not differ seasonally between home ranges and core areas (P = 0.752). Most deer resided in the same general area year-round and had overlapping seasonal home ranges and core areas. We conclude that stability observed in seasonal home ranges and habitat selection were influenced by relatively warm winter conditions during our study.

A New Nearctic Species ofDocosiaWinnertz Fungus Gnat (Diptera: Mycetophilidae) from Michigan

A new species of Docosia Winnertz fungus gnat was discovered in the northern Lower Peninsula of Michigan. Two adult males flew in midsummer to a Malaise trap next to a pine swamp. The flies could not be identified by key to genus because wing vein R1 was longer than allowed by the key for Docosia. Adult females and juvenile stages of Docosia mcgrawi Taber are unknown.

A New Nearctic Species of Hadroneura Lundström Fungus Gnat

The fungus gnat genus Hadroneura Lundstrom was previously known from seven species. Five occur in the far western United States and Canada including Alaska, British Columbia, and coastal California. This is the first Hadroneura species recorded in the U.S. east of the Rocky Mountains. One adult male Hadroneura huron Taber n. sp. was collected in a Malaise trap in white pine (Pinus stroba L.) forest on the northern lower peninsula of Michigan. Females and juvenile stages are unknown.

Accounting for Age Structure and Spatial Structure in Eco-Evolutionary Analyses of a Large, Mobile Vertebrate.

The idealized concept of a population is integral to ecology, evolutionary biology, and natural resource management. To make analyses tractable, most models adopt simplifying assumptions, which almost inevitably are violated by real species in nature. Here, we focus on both demographic and genetic estimates of effective population size per generation (Ne), the effective number of breeders per year (Nb), and Wright's neighborhood size (NS) for black bears (Ursus americanus) that are continuously distributed in the northern lower peninsula of Michigan, United States. We illustrate practical application of recently developed methods to account for violations of 2 common, simplifying assumptions about populations: 1) reproduction occurs in discrete generations and 2) mating occurs randomly among all individuals. We use a 9-year harvest dataset of >3300 individuals, together with genetic determination of 221 parent-offspring pairs, to estimate male and female vital rates, including age-specific survival, age-specific fecundity, and age-specific variance in fecundity (for which empirical data are rare). We find strong evidence for overdispersed variance in reproductive success of same-age individuals in both sexes, and we show that constraints on litter size have a strong influence on results. We also estimate that another life-history trait that is often ignored (skip breeding by females) has a relatively modest influence, reducing Nb by 9% and increasing Ne by 3%. We conclude that isolation by distance depresses genetic estimates of Nb, which implicitly assume a randomly mating population. Estimated demographic NS (100, based on parent-offspring dispersal) was similar to genetic NS (85, based on regression of genetic distance and geographic distance), indicating that the >36000 km2 study area includes about 4-5 black-bear neighborhoods. Results from this expansive data set provide important insight into effects of violating assumptions when estimating evolutionary parameters for long-lived, free-ranging species. In conjunction with recently developed analytical methodology, the ready availability of nonlethal DNA sampling methods and the ability to rapidly and cheaply survey many thousands of molecular markers should facilitate eco-evolutionary studies like this for many more species in nature.

Survival of Female White-Tailed Deer (Odocoileusvirginianus) in the Northern Lower Peninsula of Michigan

Abstract. Wildlife biologists require demographic estimates to manage white-tailed deer (Odocoileus virginianus) populations. However, such data are sparse for deer in the northern lower peninsula of Michigan. During 2005–2008, we radiomarked 105 female white-tailed deer (62 adults and 43 fawns) in the northern lower peninsula of Michigan to quantify rates of survival and determine causes of mortality. Annual adult survival was 0.64±0.06 (mean ± SE) and similar to other northern deer studies, with most mortalities (n = 14 of 31) caused by hunting and deer-vehicle collisions (n = 5). Adult survival was the highest during winter (1.00) and lowest in fall (0.70±0.07). Survival of fawns during the winter–spring period was 0.74 ± 0.06 and within ranges of other northern deer studies, with all mortalities caused by predation (n = 4) and starvation (n = 3). These survival rates indicate the local deer population may be able to achieve higher densities and provide current information to parameterize population mo...

Influence of Movement Dynamics on Walleye Harvest Management in Intermixed Fisheries in a Chain of Lakes

AbstractFish populations that exhibit movement patterns present challenges to fishery management. In the Inland Waterway in Michigan's northern Lower Peninsula, monitoring Walleye Sander vitreus population dynamics and harvest management is difficult because of seasonal intermixing among interconnected lakes. In addition, the presence of tribal subsistence fishing and recreational angling fisheries that occur during different discrete time periods adds complexity to understanding harvest management performance. We used stochastic simulation to determine the influence of movement and harvest dynamics on the performance of harvest management targets for Walleye in our study system. After accounting for postspawn movement and harvest dynamics, our results indicated that population‐specific exploitation rates on average did not exceed the target rates (u = 0.35) that are mandated in the waterway. We did, however, determine that some areas are at risk because they experienced population‐specific exploitation rates that surpassed the target. We also determined that the interplay between movement and uncertain population and harvest dynamics will likely determine the ability of management to meet currently accepted harvest targets on average over time, as well as the risk of exceeding harvest targets each year. Our findings are broadly applicable for mobile species inhabiting lake chains and highlight that it is critical for managers to gain an understanding of movement as well as harvest dynamics, because both are imperative for understanding how these dynamics influence harvest management performance. As such, we recommend that managers of Walleye populations in other waterways implement tagging studies and harvest monitoring programs to gain an understanding of movement rates and harvest dynamics. An understanding of movement and harvest dynamics along with the stochastic simulation framework we used provides a better understanding of complex system dynamics and leads to informed harvest management decisions.Received July 30, 2016; accepted January 6, 2017 Published online March 31, 2017

Detection of Snake Fungal Disease from aLampropeltis triangulum(Eastern Milksnake) in Northern Michigan

Abstract An alarming number of cases of Snake Fungal Disease (SFD), a condition frequently resulting in morbidity and mortality in snakes, have been documented in numerous species across much of the eastern US. We sampled a skin lesion on the face of a free-ranging Lampropeltis triangulum (Eastern Milksnake) from the northern Lower Peninsula of Michigan. The lesion tested positive for Ophidiomyces ophiodiicola, the causative agent of SFD. Our results document the second species from Michigan known to be infected with SFD. This case adds to the growing body of literature detailing the distribution of snake species affected, and further indicates that this pathogen is widespread in the eastern US. We stress the continued need for increased, systematic sampling efforts to determine the species affected by SFD and the potentially deleterious impacts it has on snake populations.

Effects of sampling scale on American black bear spatial genetic structure

Abstract: Sampling bias can lead to erroneous interpretations of spatial genetic structure that can subsequently impact conservation efforts and management decisions. Genetic sampling of rare and elusive species can be challenging and, by necessity, samples are often collected opportunistically from multiple sources that could differ in spatial dispersion and timing of collection. Here we quantified the effects of timing of sample collection and sampling methods on spatial and temporal variability in sample dispersion and measures of American black bear (Ursus americanus) local spatial genetic structure. Hair (N = 890) and tissue (N = 1,017) samples were collected from Michigan's Northern Lower Peninsula (USA) during the summer using non-invasive (hair snares) and autumn harvest methods during 2003, 2005, and 2009. Point pattern analyses of sample dispersion revealed that sample density did not differ significantly between seasons or among years. Measures of spatial genetic structure (i.e., spatial autoc...

Modeling habitat potential for elk expansion in Michigan, USA

ABSTRACT Elk (Cervus elaphus) range expansion and reintroduction is a topic of national interest in wildlife management. Eastern states are facilitating the recolonization of elk to historic ranges. Success of these herds depends on habitat evaluations, site-specific considerations of human tolerance to elk and interactions between elk and existing wildlife. Interest in elk restoration has increased for multiple stakeholders in Michigan (USA), where prospering elk suggest there is potential for range expansion. Habitat quality at the landscape scale for elk in Michigan depends primarily on available forage, suitable cover, habitat diversity, and road densities so we quantified these factors in the Upper Peninsula and northern Lower Peninsula of Michigan using a habitat suitability index model framework. We focused our analysis on target areas of interest and compared habitat suitability values occurring at those locations to values occurring within the current elk range (Pigeon River County State Forest area, or Pigeon River). We used elk habitat utilization information associated with the Pigeon River to validate and adjust our habitat suitability model. We also included a model that assigned less weight to the road density parameter, to account for uncertainty regarding the influence of roads on elk. Results from our habitat models suggested that patches of moderately suitable habitat exist outside the Pigeon River range in Michigan. Target areas differed in quality and quantity of habitat when compared to existing elk range, but habitat suitability values overlapped considerably among locations. Large patches of moderately suitable habitat also occurred outside of target areas. Results suggest that Michigan has potential to support an expanded elk range; however, additional site-specific considerations (land ownership, winter snowpack, deer-elk interaction, wolf density) likely need to be accounted for at potential restoration and expansion sites.

Resting Site Characteristics of American Marten in the Northern Lower Peninsula of Michigan

Abstract American marten are associated with forests that are characteristically late successional, closed canopy, and diverse in structure; these attributes meet their habitat requirements and provide resting sites. However, the small populations of marten in Michigan's Northern Lower Peninsula face modern habitat conditions that are fragmented and considerably altered from presettlement environments. Resting site structures are required habitat components that are used daily and provide protection from predation and inclement weather but may be limiting and require active management to preserve. We identified resting site characteristics of American marten in the Manistee National Forest from May 2011 to December 2013. Twenty-five marten (15 male and 10 female) were monitored to identify resting sites. We identified 522 unique resting site structures; tree cavities (n = 255, 48.9%), branches (n = 162, 31%), and nests (n = 90, 17.2%) were most commonly observed. During the summer (April–September) marten...

Using audio lures to improve golden‐winged warbler (Vermivora chrysoptera) detection during point‐count surveys

ABSTRACTThe golden‐winged warbler (Vermivora chrysoptera) is a Neotropical migratory songbird listed as a “Bird of Conservation Concern” by the U.S. Fish and Wildlife Service. To manage golden‐winged warblers, it is important to develop effective survey techniques for conservation research and monitoring. We conducted point counts in 1–8‐year‐old aspen (Populus sp.) stands in the northern Lower Peninsula of Michigan (USA), during 2011, to estimate detection probability of golden‐winged warblers, with and without an electronic broadcast of a golden‐winged warbler song (i.e., audio lure). We compared audio lure effectiveness for detecting golden‐winged warblers during fixed‐ (50‐m radius) and variable‐radius point counts. Golden‐winged warbler detection estimates were = 0.84 (95% CI = 0.39–0.98) and = 0.22 (0.11–0.40) for fixed‐radius point counts, with and without audio lure, respectively. For variable‐radius point counts, golden‐winged warbler detection estimates were = 0.79 (CI = 0.51–0.93) and = 0.57 (0.42–0.71), with and without audio lure, respectively. We also estimated the number of 3‐minute sub‐counts required to achieve detection probability ≥95% for both radii, with and without audio lures. We found that 2 sub‐counts with audio lure resulted in &gt;95% detection probability for golden‐winged warblers at both radii. Without audio lure, 12 and 4 sub‐counts were required for fixed and variable radii, respectively. Regardless of survey technique, golden‐winged warbler detection probability was always &lt;1.0, which highlights the importance of accounting for imperfect detection of golden‐winged warblers. Our results indicate that the use of an audio lure is an effective design technique for improving detectability of golden‐winged warblers. © 2014 The Wildlife Society.

Visualization of temporal change in soundscape power of a Michigan lake habitat over a 4-year period

Soundscape Ecology is an emerging area of science that does not focus on the identification of species in the soundscape but attempts to characterize sounds by organizing them into those produced by biological organisms such as birds, amphibians, insects or mammals; physical environmental factors such as thunder, rainfall or wind; and sounds produced by human entities such as airplanes, automobiles or air conditioners. The soundscape changes throughout the day and throughout the seasons. The soundscape components that create the sound occur at different frequencies. A set of metrics termed soundscape power was computed and visualized to examine the patterns of daily and seasonal change in the soundscape.Automated recorders were used to record soundscape samples every half hour for one minute duration from six sites on an uninhabited island in Twin Lakes located near Cheboygan in Michigan's northern Lower Peninsula. Each recording was divided into 1kHz frequency intervals and visualization tools were used to examine the soundscape power in each interval during 48 half-hour time segments from April–October for four consecutive years. Daily patterns of soundscape power change were also examined during the seven month sample period. To synthesize the data set, three dimensional contour plots were used to visualize day of the year (x), time of day (y) and soundscape power (z) for several frequency intervals. A further synthesis was developed to visualize soundscape change using a Normalized Difference Soundscape Index (NDSI) which is a ratio of low to high frequencies.The visualization of the soundscape revealed discrete patterns in the soundscape including striking changes in the time of the occurrence of dawn and dusk choruses. The patterns in the soundscape were remarkably similar over the four-year investigation. Soundscape power in the lower frequency examined (1–2kHz) was a dominant feature of the soundscape at Twin Lakes and the low frequency soundscape power was negatively correlated with higher frequency sounds.The soundscape power metrics and the visualizations of the soundscape produced in this study should provide a means of rapidly synthesizing large numbers of recordings into meaningful patterns to examine soundscape change. This is especially useful because of the need to develop indices of ecological metrics based on soundscape attributes to assist resource managers in making decisions about ecosystem integrity. Visualization can also be of immense benefit to examine patterns in large soundscape time series data sets that can be produced by automated recording devices.