Sequential Decision Plans in Monitoring Benthic Macroinvertebrates: Cost Savings, Classification Accuracy, and Development of Plans

1988 ◽  
Vol 45 (2) ◽  
pp. 280-286 ◽  
Author(s):  
John K. Jackson ◽  
Vincent H. Resh
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Benthic Macroinvertebrates ◽  
Sampling Error ◽  
Cost Savings ◽  
Spatial And Temporal Variation ◽  
Classification Error ◽  
Sequential Decision ◽  
Data Set ◽  
Acceptable Risks

Sequential decision plans provide a statistical approach that can reduce the number of benthic sample units needed to classify a site as impacted or unimpacted, thus reducing the cost of using benthic macroinvertebrates in water quality assessment programs. These plans require information about unimpacted and impacted conditions, the mathematical distribution of the data, and acceptable risks of classification error. A large benthic data set (n = 55) was used for simulations that created and tested sequential decision plans. Using 10–60% reductions in species richness, mayfly (Cinygmula) population density, and species diversity as definitions of impact in the simulations, the average number of sample units processed for identification of the unimpacted reference site was reduced (compared with fixed sample-size methods that are commonly used) by 50–64% for species richness, 59–79% for density estimates, and 51–55% for species diversity. Unimpacted data sets were initially classified as representing impacted conditions in 0–5% of the cases. If classifications are to be interpreted properly, sampling error and spatial and temporal variation in biological parameters must be considered when sequential decision plans are created.

Optimizing efficiency of height modeling for extensive forest inventories

2006 ◽  
Vol 36 (9) ◽  
pp. 2259-2269 ◽  
Author(s):  
T M Barrett
Keyword(s):  
Travel Time ◽  
Programming Model ◽  
Sampling Error ◽  
Estimation Error ◽  
Cost Savings ◽  
Data Set ◽  
Potential Measurement ◽  
Forest Inventories ◽  
Alternative Measurement ◽  
Measurement Strategies

Although critical to monitoring forest ecosystems, inventories are expensive. This paper presents a generalizable method for using an integer programming model to examine tradeoffs between cost and estimation error for alternative measurement strategies in forest inventories. The method is applied to an example problem of choosing alternative height-modeling strategies for 1389 plots inventoried by field crews traveling within an 82.5 × 106 ha region of the west coast of North America during one field season. In the first part of the application, nonlinear regional height models were constructed for 38 common species using a development data set of 137 374 measured tree heights, with root mean square error varying from 6.7 to 2.1 m. In the second part of the application, alternative measurement strategies were examined using a minimal cost objective subject to constraints on travel time and estimation error. Reduced travel time for field crews can be a significant portion of the cost savings from modeling tree heights. The optimization model was used to identify a height-modeling strategy that, given assumptions made, resulted in <10% of maximum average plot volume error, >33% of potential measurement cost savings, and small bias for estimates of regional volume and associated sampling error (0.1% and 0.4%, respectively).

scholarly journals Indicators for the Sea-floor Integrity of the Hellenic Seas under the European Marine Strategy Framework Directive: establishing the thresholds and standards for Good Environmental Status

2012 ◽  
Vol 13 (1) ◽  
pp. 140 ◽  
Author(s):  
N. SIMBOURA ◽  
A. ZENETOS ◽  
M.A. PANCUCCI-PAPADOPOULOU ◽  
S. REIZOPOULOU ◽  
N. STREFTARIS
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Ecological Status ◽  
Sensitive Species ◽  
Marine Strategy Framework Directive ◽  
Data Set ◽  
Sea Floor ◽  
Tolerant Species ◽  
Environmental Status ◽  
Good Environmental Status

A data set of 625 samples of benthic macroinvertebrates collected from the Hellenic Seas (Ionian and Aegean) was used to establish thresholds and reference standards for two of the indicators addressing the descriptors of Sea-floor Integrity under the Marine Strategy Framework Directive (MSFD): species diversity and richness and the ratio of sensitive species to tolerant species. The dataset was categorised according to the baseline ecological status assessment of the respective water bodies under the Water Framework Directive (WFD). Species diversity and richness were characterised using the Shannon diversity and species richness indices, respectively, and were analysed for three pre-defined substrate types, three depth zones and three sample-size categories, and the significant categories were statistically validated. Good Environmental Status (GEnS) threshold and reference values were established for the valid combinations of categories denoted as ‘ecotypes’ through the use of a boxplot and an analysis of variance. The limitations and specifications for an overall GEnS assessment using the above indices are highlighted based on the WFD experience. For the ratio of sensitive species to tolerant species, the BENTIX index classification scale is proposed for GEnS assessment, and an integrated approach to the assessment of diversity and species richness is suggested. Finally, the regionality of the tested indices in relation to the two Mediterranean sub-regions, including the Hellenic area, was tested.

scholarly journals Carbon Stocks, Species Diversity and Their Spatial Relationships in the Yucatán Peninsula, Mexico

2021 ◽  
Vol 13 (16) ◽  
pp. 3179
Author(s):  
José Luis Hernández-Stefanoni ◽  
Miguel Ángel Castillo-Santiago ◽  
Juan Andres-Mauricio ◽  
Carlos A. Portillo-Quintero ◽  
Fernando Tun-Dzul ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Tropical Forests ◽  
Field Data ◽  
Yucatan Peninsula ◽  
Carbon Stocks ◽  
Carbon Density ◽  
Radar Backscatter ◽  
Data Set ◽  
Yucatán Peninsula

Integrating information about the spatial distribution of carbon stocks and species diversity in tropical forests over large areas is fundamental for climate change mitigation and biodiversity conservation. In this study, spatial models showing the distribution of carbon stocks and the number of species were produced in order to identify areas that maximize carbon storage and biodiversity in the tropical forests of the Yucatan Peninsula, Mexico. We mapped carbon density and species richness of trees using L-band radar backscatter data as well as radar texture metrics, climatic and field data with the random forest regression algorithm. We reduced sources of errors in plot data of the national forest inventory by using correction factors to account for carbon stocks of small trees (<7.5 cm DBH) and for the temporal difference between field data collection and imagery acquisition. We created bivariate maps to assess the spatial relationship between carbon stocks and diversity. Model validation of the regional maps obtained herein using an independent data set of plots resulted in a coefficient of determination (R2) of 0.28 and 0.31 and a relative mean square error of 38.5% and 33.0% for aboveground biomass and species richness, respectively, at pixel level. Estimates of carbon density were influenced mostly by radar backscatter and climatic data, while those of species richness were influenced mostly by radar texture and climatic variables. Correlation between carbon density and species richness was positive in 79.3% of the peninsula, while bivariate maps showed that 39.6% of the area in the peninsula had high carbon stocks and species richness. Our results highlight the importance of combining carbon and diversity maps to identify areas that are critical—both for maintaining carbon stocks and for conserving biodiversity.

How Much Do Consumers Value Fuel Economy and Performance? Evidence from Technology Adoption

2021 ◽  
pp. 1-45
Author(s):  
Benjamin Leard ◽  
Joshua Linn ◽  
Yichen Christy Zhou
Keyword(s):  
Fuel Economy ◽  
Cost Savings ◽  
Data Set ◽  
Fuel Savings ◽  
Unique Data ◽  
Consumer Benefit ◽  
Novel Approach ◽  
High Valuation ◽  
And Performance ◽  
Historical Periods

Abstract During historical periods in which US fuel economy standards were unchanging, automakers increased performance but not fuel economy, contrasting with recent periods of tightening standards and rising fuel economy. This paper evaluates the welfare consequences of automakers forgoing performance increases to raise fuel economy as standards have tightened since 2012. Using a unique data set and a novel approach to account for fuel economy and performance endogeneity, we find undervaluation of fuel cost savings and high valuation of performance. Welfare costs of forgone performance approximately equal expected fuel savings benefits, suggesting approximately zero net private consumer benefit from tightened standards.

scholarly journals What Does Productivity Really Mean? Towards an Integrative Paradigm in the Search for Biodiversity-Productivity Relationships

2013 ◽  
Vol 41 (1) ◽  
pp. 36 ◽  
Author(s):  
Liangjun HU ◽  
Qinfeng GUO
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Biomass Production ◽  
Real Root ◽  
Spatial Scaling ◽  
Ecological Processes ◽  
The Real ◽  
Community Or ◽  
Per Se ◽  
Underlying Mechanisms

How species diversity relates to productivity remains a major debate. To date, however, the underlying mechanisms that regulate the ecological processes involved are still poorly understood. Three major issues persist in early efforts at resolution. First, in the context that productivity drives species diversity, how the pathways operate is poorly-explained. Second, productivity  per se varies with community or ecosystem maturity. If diversity indeed drives productivity, the criterion of choosing appropriate measures for productivity is not available. Third, spatial scaling suggests that sampling based on small-plots may not be suitable for formulating species richness-productivity relationships (SRPRs). Thus, the long-standing assumption simply linking diversity with productivity and pursuing a generalizing pattern may not be robust. We argue that productivity, though defined as ‘the rate of biomass production’, has been measured in two ways environmental surrogates and biomass production leading to misinterpretations and difficulty in the pursuit of generalizable SRPRs. To tackle these issues, we developed an integrative theoretical paradigm encompassing richer biological and physical contexts and clearly reconciling the major processes of the systems, using proper productivity measures and sampling units. We conclude that loose interpretation and confounding measures of productivity may be the real root of current SRPR inconsistencies and debate.

scholarly journals Composition and diversity of anurans in the Restinga of the Conde municipality, northern coast of the state of Bahia, northeastern Brazil

2016 ◽  
Vol 16 (3) ◽  
Author(s):  
Felipe Augusto Trindade Gondim-Silva ◽  
Alessandra Rodrigues Santos Andrade ◽  
Rafael Oliveira Abreu ◽  
Jamile Santos Nascimento ◽  
Geovane Paixão Corrêa ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Species Composition ◽  
Rainy Season ◽  
Dominant Species ◽  
The State ◽  
Northeastern Brazil ◽  
Freshwater Wetland ◽  
Northern Coast ◽  
Anuran Species

Abstract The Conde municipality is located in the northern coast of the state of Bahia (NC), northeastern Brazil, and is part of the Atlantic Tropical domain. The anuran fauna of the northern portion of the NC is still poorly known if compared to the southern portion. The Restinga is one of the predominant environments of the coastal plains of the NC and it is characterized essentially by presenting sandy soil covered by herbaceous and shrubby vegetation. The objective of this study was to determine the anuran species composition and diversity for the Restinga of the Conde municipality. Sampling was carried out at night by active search over four periods of five consecutive days each, two over the 'main rainy season' and two in a 'lesser rainy season', using 14 sample units (SUs) and five extra sample plots (EPs). We calculated dominance and species diversity using the Berger-Parker and Shannon-Wiener H' indices, respectively. We used accumulation curves and the Jackknife 1 estimator to estimate anuran species richness, considering only the data obtained from the SUs. We recorded 713 anuran specimens distributed within 33 species, 13 genera and five families (Bufonidae, Craugastoridae, Hylidae, Leptodactylidae and Microhylidae). The Hylidae and Leptodactylidae families had the highest species richness. Considering only the SUs (Jackknife 1 estimator in brackets), we recorded 28 species in the study area (33.9 ± 2.3), 13 in Shrubby Vegetation Zones - SVZ (20.8 ± 2.9) and 25 in Freshwater Wetland Zones - FWZ (28.9 ± 1.9). The abundance and species diversity of the FWZ (n = 638 specimens; H'= 2.4) were higher than those recorded for the SVZ (n = 52 specimens; H' = 1.9). The SVZ and FWZ showed distinct dominant species, wherein Pristimantis paulodutrai was the dominant species in SVZ and Scinax fuscomarginatus in FWZ. The Restinga of the Conde municipality stands out as the one with the highest anuran species richness already recorded considering only SVZ and FWZ. Moreover, its anuran species composition represented 55% of the anuran species known for the NC and included taxa common to three different morphoclimatic domains (Tropical Atlantic, Cerrado and Caatinga).

scholarly journals Fish species diversity in headwaters streams of Paraguay and Paraná Basins

2007 ◽  
Vol 50 (6) ◽  
pp. 1033-1042 ◽  
Author(s):  
Yzel Rondon Súarez ◽  
Sabrina Bigatão Valério ◽  
Karina Keyla Tondado ◽  
Alexandro Cezar Florentino ◽  
Thiago Rota Alves Felipe ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Environmental Factors ◽  
Fish Species ◽  
Total Species Richness ◽  
Paraná Basin ◽  
Parana Basin ◽  
Number Of Individuals ◽  
Total Species ◽  
Fish Species Diversity

The influence of spatial, temporal and environmental factors on fish species diversity in headwater streams in Paraguay and Paraná basins, Brazil was examined. A total of 4,605 individuals were sampled, distributed in 60 species. The sampled streams in Paraná basin presented a larger total species richness (42) than Paraguay streams (40). However the estimated richness was larger in Paraguay basin (53) than Paraná streams (50). The streams of Paraná basin had a greater mean species richness and evenness, while more individuals per sample were found in the Paraguay basin. Difference between the sub-basins were found in the Paraguay basin, while for the basin of Paraná, richness and evenness vary significantly between the sub-basins, but the number of individuals varied seasonally. The most important environmental factors to species diversity and abundance were altitude, water temperature, stream width and stream depth for both the basins.

scholarly journals Increased mosquito abundance and species richness in Connecticut, United States 2001–2019

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tanya A. Petruff ◽  
Joseph R. McMillan ◽  
John J. Shepard ◽  
Theodore G. Andreadis ◽  
Philip M. Armstrong
Keyword(s):  
United States ◽  
Species Richness ◽  
Community Composition ◽  
Pathogen Transmission ◽  
Public Health Importance ◽  
Data Set ◽  
Mosquito Abundance ◽  
Total Species Richness ◽  
Multiple Species ◽  
Total Species

Abstract Historical declines in multiple insect taxa have been documented across the globe in relation to landscape-level changes in land use and climate. However, declines have either not been universally observed in all regions or examined for all species. Because mosquitoes are insects of public health importance, we analyzed a longitudinal mosquito surveillance data set from Connecticut (CT), United States (U.S.) from 2001 to 2019 to identify changes in mosquito community composition over time. We first analyzed annual site-level collections and metrics of mosquito community composition with generalized linear/additive mixed effects models; we also examined annual species-level collections using the same tools. We then examined correlations between statewide collections and weather variables as well as site-level collections and land cover classifications. We found evidence that the average trap night collection of mosquitoes has increased by ~ 60% and statewide species richness has increased by ~ 10% since 2001. Total species richness was highest in the southern portion of CT, likely due to the northward range expansion of multiple species within the Aedes, Anopheles, Culex, and Psorophora genera. How the expansion of mosquito populations in the northeast U.S. will alter mosquito-borne pathogen transmission in the region will require further investigation.

Diverse perennial crop mixtures sustain higher productivity over time based on ecological complementarity

2011 ◽  
Vol 26 (4) ◽  
pp. 317-327 ◽  
Author(s):  
Valentín D. Picasso ◽  
E. Charles Brummer ◽  
Matt Liebman ◽  
Philip M. Dixon ◽  
Brian J. Wilsey
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Biomass Production ◽  
Cropping Systems ◽  
Individual Species ◽  
Selection Effects ◽  
Complementarity Effect ◽  
Change Over Time ◽  
Diversity Effects ◽  
Over Time

AbstractCropping systems that rely on renewable energy and resources and are based on ecological principles could be more stable and productive into the future than current monoculture systems with serious unintended environmental consequences such as soil erosion and water pollution. In nonagricultural systems, communities with higher species diversity have higher productivity and provide other ecosystem services. However, communities of well-adapted crop species selected for biomass production may respond differently to increasing diversity. Diversity effects may be due to complementarity among species (complementary resource use and facilitative interactions) or positive selection effects (e.g., species with higher productivity dominate the mixture), and these effects may change over time or across environments. Our goal was to identify the ecological mechanisms causing diversity effects in a biodiversity experiment using agriculturally relevant species, and evaluate the implications for the design of sustainable cropping systems. We seeded seven perennial forage species in a replicated field experiment at two locations in Iowa, USA, and evaluated biomass productivity of monocultures and two- to six-species mixtures over 3 years after the establishment year under management systems of contrasting intensity: one or three harvests per year. Productivity increased with seeded species richness in all environments, and the positive relationship did not change over time. Polyculture overyielding was due to complementarity among species in the community rather than to selection effects of individual species. Complementarity increased as a log-linear function of species richness in all environments, and this trend was consistent across years. Legume–grass facilitation may explain much of this complementarity effect. Although individual species with high biomass production had a major effect on productivity of mixtures, the species producing the highest biomass in monoculture changed over the years in most environments. Furthermore, transgressive overyielding was observed and was more prevalent in later years, in some environments. We conclude that choosing a single well-adapted species for maximizing productivity may not be the best alternative over the long term and that high levels of species diversity should be included in the design of productive and ecologically sound agricultural systems.

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