Observer error in sampling a rare plant population

Background: Estimation of abundance in vegetation sampling involving observers is almost always characterised by observer error, although such error is rarely reported. Aims: To quantify observer error in population estimation of the rare plant species Physaria filiformis in Missouri, USA. Methods: The abundance of P. filiformis was estimated within 25-m2 plots by six trained observers with varying experience levels over 10 years. Observers assigned plots to six predefined density classes. A total of 477 plots were estimated annually, and actual counts were conducted on ca. 10% of the plots to assess per cent agreement of estimates with counts. Results: Over a third of the estimates of plant abundance evaluated for accuracy (36.4%) deviated from exhaustive counts. The majority of the misestimates were underestimates by one density class (29.4%). The number and type of misestimates varied systematically with density class. Conclusions: Observer error could be explained to some degree by variation in population density, but not by experience. It appears that inherent differences exist among observers that cannot be entirely compensated for by experience or training. Observer error in this system represents a systematic bias, and can be compensated for by use of correction factors, which would ideally be both density class-dependent and observer-specific

Standardization and quality control in data collection and assessment of threatened plant species

Informative data collection is important in the identification and conservation of rare plant species. Data sets generated by many small-scale studies may be integrated into large, distributed databases, and statistical tools are being developed to extract meaningful information from such databases. A diversity of field methodologies may be employed across smaller studies, however, resulting in a lack of standardization and quality control, which makes integration more difficult. Here, we present a case study of the population-level monitoring of two threatened plant species with contrasting life history traits that require different field sampling methodologies: the limestone glade bladderpod, Physaria filiformis, and the western prairie fringed orchid, Plantanthera praeclara. Although different data collection methodologies are necessary for these species based on population sizes and plant morphology, the resulting data allow for similar inferences. Different sample designs may frequently be necessary for rare plant sampling, yet still provide comparable data. Various sources of uncertainty may be associated with data collection (e.g., random sampling error, methodological imprecision, observer error), and should always be quantified if possible and included in data sets, and described in metadata. Ancillary data (e.g., abundance of other plants, physical environment, weather/climate) may be valuable and the most relevant variables may be determined by natural history or empirical studies. Once data are collected, standard operating procedures should be established to prevent errors in data entry. Best practices for data archiving should be followed, and data should be made available for other scientists to use. Efforts to standardize data collection and control data quality, particularly in small-scale field studies, are imperative to future cross-study comparisons, meta-analyses, and systematic reviews

Bird Monitoring at Homestead National Monument of America, Nebraska, Status Report 2009–2017

Executive Summary In 2009, the Heartland Inventory Monitoring Network initiated breeding bird surveys on Homestead National Monument of America, Nebraska, to address two objectives: (1) to monitor changes in bird community composition and abundance, and (2) to improve our understanding of relationships between breeding birds and habitat, and the effects of management actions on those relationships. This report evaluates trends in the park’s breeding bird populations in the context of trends observed within the North American Bird Conservation Initiative’s (NABCI) Central Mixed Grass Prairie Bird Conservation Region, the region in which the park is located. By doing so, we can assess the influence of park habitat management on bird populations with an understanding of regional population trends that are outside the influence of natural resource management activities at the Homestead national Monument of America. Eighty-six species of birds were recorded during May and June site visits in the nine years since initiating monitoring. Seventy-four of the species are considered breeding species because they are permanent or summer residents. Two of the breeding species recorded on Homestead National Monument of America are species of concern for the Central Mixed Grass Prairie Bird Conservation Region. Thirteen species were observed during the survey period in sufficient numbers to calculate annual abundances and trends with some degree of confidence. The American Goldfinch (Spinus tristis), Dickcissel (Spiza americana), House Wren (Troglodytes aedon), and Red-winged Blackbird (Agelaius phoeniceus) were the most abundant and widespread species on Homestead National Monument of America. Comparing population trends of the thirteen most recorded species on the park with regional trends for the Central Mixed Grass Prairie Bird Conservation Region were inconclusive, but suggest that trends in populations on the park were similar to trends in populations found region-wide for most species present. However, some differences in population trends were observed between the park and the region. This report provides current regional and local trends for breeding birds for future comparisons with bird data collected as part of the long-term monitoring efforts at Homestead National Monument of America. This information will help park staff plan management objectives, and assess the effectiveness of management alternatives. These monitoring data also provide park staff with additional information for interpreting natural resources

Bird Monitoring at Herbert Hoover National Historic Site, Iowa, Status Report 2005–2017

Executive Summary In 2005, the Heartland Inventory & Monitoring Network initiated breeding bird surveys on Herbert Hoover National Historic Site, Iowa, to address two objectives: (1) to monitor changes in bird community composition and abundance, and (2) to improve our understanding of relationships between breeding birds and habitat, and the effects of management actions on those relationships. This report evaluates trends in the park’s breeding bird populations in the context of trends observed within the North American Bird Conservation Initiative’s (NABCI) Eastern Tallgrass Prairie Bird Conservation Region , the region in which the park is located. By doing so, we can assess the influence of park habitat management on bird populations with an understanding of regional population trends that are outside the influence of natural resource management activities at Herbert Hoover National Historic Site. Sixty-eight species of birds were recorded during May and June site visits in the twelve years since initiating monitoring. Sixty-seven of the species are considered breeding species because they are permanent or summer residents. Seven of the breeding species recorded on Herbert Hoover National Historic Site are species of concern for the Eastern Tallgrass Prairie Bird Conservation Region. Eight species were observed during the survey period in sufficient numbers to calculate annual abundances and trends with some degree of confidence. The American Robin (Turdus migratorius) and Red-winged Blackbird (Agelaius phoeniceus) were the most abundant and widespread species on Herbert Hoover National Historic Site. Comparing population trends on the park with regional trends suggest that populations of the most common species on the park were similar to those of the region, especially for American Goldfinch (Spinus tristis), Common Grackle (Quiscalus quiscula), Common Yellowthroat (Geothlypis trichas), Dickcissel (Spiza americana), and Mourning Dove (Zenaida macroura). The population of Eastern Meadowlark (Sturnella magna) on the park was doing slightly better than the population region-wide. One of the species that was common and widespread on the park, American Robin, had an uncertain park population trend, but a region-wide trend that was increasing. The other common and widespread species, Red-winged Blackbird, had a population trend that was declining both on the park and across the region. This report provides current regional and local trends for breeding birds for future comparisons with bird data collected as part of the long-term monitoring efforts at Herbert Hoover National Historic Site. This information will help park staff plan management objectives and assess the effectiveness of management alternatives. These monitoring data also provide park staff with additional information for interpreting natural resources

Long-term Aquatic Invertebrate Monitoring at Buffalo National River, Arkansas

Aquatic invertebrate community structure was used to assess long-term water quality integrity in the mainstem of the Buffalo National River, Arkansas from 2005 to 2013. Nine benthic invertebrate samples were collected from each of six sampling sites using a Slack-Surber sampler. The Stream Condition Index (SCI) developed for Ozark streams was used to assess integrity of the invertebrate communities. This index is calculated using taxa richness, EPT (Ephemeroptera, Plecoptera, Trichoptera) Richness, Shannon’s Diversity Index, and Hilsenhoff Biotic Index (HBI). Sørensen’s similarity index was used to assess community similarity among sites, and scores were then analyzed using ascendant hierarchical cluster analysis. The benthic invertebrate fauna was diverse with 167 distinct taxa identified from all sites, with similarities ranging from 70% to 83%. Cluster analysis showed that sites were clustered in a longitudinal progression, with those sites closest to one another in linear distance generally being the most closely related. Overall, the invertebrate taxa of the Buffalo River are largely intolerant (mean tolerance value= 4.38). Taxa richness was typically greater than 20 among samples, and EPT richness values consistently were greater than 12 for all sites in most years. Shannon’s diversity index values generally ranged from 2.0 to 2.5 among sites and years. Metric values tended to decrease in a downstream direction to Site 4, and then increase to levels observed upstream. The exception was for HBI, which did not show this response and values for this metric generally were below 5. SCI scores among sampling sites were variable but not generally impaired and were fully biologically-supporting. Water quality (temperature, dissolved oxygen, specific conductance, pH, turbidity) met state standards in all instances. Habitat data were summarized, but found to be poorly correlated with invertebrate metrics (\u3c30% significant). Although the condition of invertebrate communities and water quality in the Buffalo River are largely sound and have high integrity, numerous ongoing and projected threats to these resources remain, and those threats largely originate outside of the park’s jurisdictional boundaries. Inherent variability of invertebrate community diversity and density across sites and years highlights the importance of using multi-metric assessment and multiyear monitoring to support management decisions

Protocol for Monitoring Fish Communities in Small Streams in the Heartland Inventory and Monitoring Network, Version 2.0

Executive Summary Fish communities are an important component of aquatic systems and are good bioindicators of ecosystem health. Land use changes in the Midwest have caused sedimentation, erosion, and nutrient loading that degrades and fragments habitat and impairs water quality. Because most small wadeable streams in the Heartland Inventory and Monitoring Network (HTLN) have a relatively small area of their watersheds located within park boundaries, these streams are at risk of degradation due to adjacent land use practices and other anthropogenic disturbances. Shifts in the physical and chemical properties of aquatic systems have a dramatic effect on the biotic community. The federally endangered Topeka shiner (Notropis topeka) and other native fishes have declined in population size due to habitat degradation and fragmentation in Midwest streams. By protecting portions of streams on publicly owned lands, national parks may offer refuges for threatened or endangered species and species of conservation concern, as well as other native species. This protocol describes the background, history, justification, methodology, data analysis and data management for long-term fish community monitoring of wadeable streams within nine HTLN parks: Effigy Mounds National Monument (EFMO), George Washington Carver National Monument (GWCA), Herbert Hoover National Historic Site (HEHO), Homestead National Monument of America (HOME), Hot Springs National Park (HOSP), Pea Ridge National Military Park (PERI), Pipestone National Monument (PIPE), Tallgrass Prairie National Preserve (TAPR), and Wilson\u27s Creek National Battlefield (WICR). The objectives of this protocol are to determine the status and long-term trends in fish richness, diversity, abundance, and community composition in small wadeable streams within these nine parks and correlate the long-term community data to overall water quality and habitat condition (DeBacker et al. 2005)

Protocol for Monitoring Aquatic Invertebrates of Small Streams in the Heartland Inventory & Monitoring Network, Version 2.1

Executive Summary The Heartland Inventory and Monitoring Network (HTLN) is a component of the National Park Service’s (NPS) strategy to improve park management through greater reliance on scientific information. The purposes of this program are to design and implement long-term ecological monitoring and provide information for park managers to evaluate the integrity of park ecosystems and better understand ecosystem processes. Concerns over declining surface water quality have led to the development of various monitoring approaches to assess stream water quality. Freshwater streams in network parks are threatened by numerous stressors, most of which originate outside park boundaries. Stream condition and ecosystem health are dependent on processes occurring in the entire watershed as well as riparian and floodplain areas; therefore, they cannot be manipulated independently of this interrelationship. Land use activities—such as timber management, landfills, grazing, confined animal feeding operations, urbanization, stream channelization, removal of riparian vegetation and gravel, and mineral and metals mining—threaten stream quality. Accordingly, the framework for this aquatic monitoring is directed towards maintaining the ecological integrity of the streams in those parks. Invertebrates are an important tool for understanding and detecting changes in ecosystem integrity, and they can be used to reflect cumulative impacts that cannot otherwise be detected through traditional water quality monitoring. The broad diversity of invertebrate species occurring in aquatic systems similarly demonstrates a broad range of responses to different environmental stressors. Benthic invertebrates are sensitive to the wide variety of impacts that influence Ozark streams. Benthic invertebrate community structure can be quantified to reflect stream integrity in several ways, including the absence of pollution sensitive taxa, dominance by a particular taxon combined with low overall taxa richness, or appreciable shifts in community composition relative to reference condition. Furthermore, changes in the diversity and community structure of benthic invertebrates are relatively simple to communicate to resource managers and the public. To assess the natural and anthropogenic processes influencing invertebrate communities, this protocol has been designed to incorporate the spatial relationship of benthic invertebrates with their local habitat including substrate size and embeddedness, and water quality parameters (temperature, dissolved oxygen, pH, specific conductance, and turbidity). Rigid quality control and quality assurance are used to ensure maximum data integrity. Detailed standard operating procedures (SOPs) and supporting information are associated with this protocol