Lucinda B. Johnson

Bio: Lucinda B. Johnson is an academic researcher from Natural Resources Research Institute. The author has contributed to research in topics: Wetland & Land use. The author has an hindex of 32, co-authored 92 publications receiving 5256 citations. Previous affiliations of Lucinda B. Johnson include United States Environmental Protection Agency & University of Minnesota.

Landscape influences on water chemistry in Midwestern stream ecosystems

Abstract: 1. Landscape characteristics of sixty-two subcatchments within the Saginaw Bay Catchment of central Michigan were examined to identify relationships with stream water chemistry. Land use, land cover and elevation were quantified for both entire catchments and the upland–river ecotone (100 m stream buffer strip). Catchment and ecotone data were then empirically compared with stream water chemistry using multivariate and regression analyses. Redundancy analysis was used to partition variance among land use, geology, and the shared influence of land use and geology. 2. Major catchments dominated by rowcrop agriculture had the highest alkalinity, total dissolved solids and nitrate + nitrite concentrations. 3. Strong seasonal differences were observed in total nitrogen and nitrite + nitrate, but not in total phosphorus or suspended solids. Land use and landscape structure factors such as slope and patch density (number of land use patches per km2) accounted for most of the observed variance in summer. 4. In both autumn and summer, landscape factors accounted for much of the observed variation in total dissolved solids and alkalinity. During autumn, geological factors and the shared influence of geology/landscape structure plus land use exerted more influence than did land use alone. 5. Total phosphorus and total suspended solids were much better explained by land use within the stream ecotone in summer than in other seasons. However, total nitrogen, nitrate, orthophosphate and alkalinity were equally well explained by land use within the ecotone and throughout the whole catchment. Only total dissolved solids in summer and ammonium in autumn were explained better by the whole catchment than the ecotone. 6. Our results show that relatively coarse spatial databases can provide useful descriptors of regional water quality.

Landscape-scale influences on stream habitats and biota

Abstract: The relative influence of geologic versus anthropogenic attributes of catchments on stream ecosystems was examined in 45 catchments of a river basin in central Michigan. Each catchment was characterized by land use, surficial geology, elevation, and hydrography, and summaries of these data were related to physical habitat characteristics that had the greatest influence on macroinvertebrate assemblages. Partial redundancy analysis revealed that geologic and land-use variables had similar magnitudes of influence on stream habitats. Of the geologic variables, catchment area, proportion of lacustrine clays, and glacial outwash materials had the strongest influence on physical habitat, particularly on channel dimensions. Row-crop agriculture and the presence of wetlands were the most important land-use variables, particularly influencing amounts of woody debris. Stream buffers (100 m) were more important than whole catchment data for predicting sediment-related habitat variables; however, channel morphology was more strongly related to whole catchments. Results suggest that catchment-wide geology and land-use characteristics may be more important than stream buffers for maintaining or restoring stream ecosystems. These techniques can be used to develop biologic signatures of catchment condition that discriminate causal factors influencing the biodiversity and health of stream ecosystems. Resume : Nous avons examine les influences respectives sur les ecosystemes des cours d'eau des attributs geologiques des bassins-versants en regard de leurs attributs anthropiques dans 45 aires d'alimentation d'un bassin fluvial du centre du Michigan (Etats-Unis). Nous avons caracterise chaque aire d'alimentation par l'utilisation du sol, la geologie de subsurface, l'elevation et l'hydrographie et nous avons rattache les sommaires des donnees ainsi obtenues aux caracteristiques de l'habitat physique qui exercaient la plus forte influence sur les communautes de macro-invertebres. L'analyse par redondance partielle a revele que les variables geologiques et les variables d'utilisation du sol exercaient sur les habitats une influence du meme ordre de grandeur. Pour ce qui est des variables geologiques, ce sont l'aire du bassin-versant ainsi que la proportion d'argiles lacustres et de materiaux stratifies fluvio-glaciaires qui ont agi le plus sur l'habitat physique, particulierement sur les dimensions du chenal. Les cultures en lignes et la presence de terres humides consituaient les plus importantes variables en matiere d'utilisation du sol, variables qui ont agi tout particulierement sur la quantite de debris ligneux. Les zones tampons (100 m) ont joue un plus grand role que les donnees sur les bassins-versants tout entiers dans la prevision des variables d'habitat relatives aux sediments; par contre, la morphologie du chenal se rattachait plus fortement aux bassins-versants tout entiers. Les resultats permettent de penser que la geologie du bassin-versant et les caracteristiques d'utilisation du sol font peut-etre plus que les zones tampons pour maintenir ou retablir les ecosystemes des cours d'eau. On peut recourir a ces techniques pour elaborer, au sujet de l'etat des bassins-versants, des signatures biologiques qui distinguent les facteurs causaux de la biodiversite et de la sante des ecosystemes des cours d'eau. (Traduit par la Redaction)

Agrochemicals increase trematode infections in a declining amphibian species

Abstract: Declining amphibian populations have been reported in the past twenty years from locations all over the world. These events have been attributed variously — often without much evidence — to habitat loss, climate change and disease. Now a case study of the northern leopard frog, Rana pipiens, in wetlands across Minnesota points to the use of agrochemicals — combined with parasitic infestation — as a contributor to population decline. The study sought factors associated with the abundance of larval trematodes in the frogs. An abundance of these parasites can be debilitating, causing limb malformation, kidney damage and death. Of more than 240 plausible predictors of trematode infection — ranging from the presence of various plant and animal species to agrochemicals and habitat geography — two stood out: the herbicide atrazine and the fertilizer, phosphate. Atrazine and phosphate are principal agrochemicals for corn and sorghum production, and together they accounted for 74% of the variation in trematode abundance. Global amphibian declines have often been attributed to disease1,2, but ignorance of the relative importance and mode of action of potential drivers of infection has made it difficult to develop effective remediation. In a field study, here we show that the widely used herbicide, atrazine, was the best predictor (out of more than 240 plausible candidates) of the abundance of larval trematodes (parasitic flatworms) in the declining northern leopard frog Rana pipiens. The effects of atrazine were consistent across trematode taxa. The combination of atrazine and phosphate—principal agrochemicals in global corn and sorghum production—accounted for 74% of the variation in the abundance of these often debilitating larval trematodes (atrazine alone accounted for 51%). Analysis of field data supported a causal mechanism whereby both agrochemicals increase exposure and susceptibility to larval trematodes by augmenting snail intermediate hosts and suppressing amphibian immunity. A mesocosm experiment demonstrated that, relative to control tanks, atrazine tanks had immunosuppressed tadpoles, had significantly more attached algae and snails, and had tadpoles with elevated trematode loads, further supporting a causal relationship between atrazine and elevated trematode infections in amphibians. These results raise concerns about the role of atrazine and phosphate in amphibian declines, and illustrate the value of quantifying the relative importance of several possible drivers of disease risk while determining the mechanisms by which they facilitate disease emergence.

Catchment and reach‐scale properties as indicators of macroinvertebrate species traits

Abstract: 1. We used catchment and reach-scale physical properties to predict the occurrence of specific species life history and behaviour traits of aquatic insects across fifty-eight catchments in a mixed land use basin. Catchment-scale attributes were derived using a geographical information system (GIS). Logistic regression techniques were used to model the relationships. 2. The reach-scale properties were highly predictive of species traits. Fourteen of the fifteen traits had significant models with concordance values greater than 68%. Cross-sectional area at bank full discharge, % shallow, slow-water habitats, and % fines were the most important variables. 3. Life history and behavioural attributes were best related to reach-scale physical features. This suggests that species traits exhibit strong relationships to local environmental conditions. 4. Catchment-scale variables had fewer significant models with species traits (four of fifteen), however these variables may have direct or indirect influence on reach-scale properties. 5. Catchment features, in particular surficial geology, influence macroinvertebrate assemblages through their control over channel morphology and hydrologic patterns. 6. The effects of land use were masked by geology (i.e. lacustrine clay geology and rowcrop agriculture were correlated), lack of detail in land use data and the aggregation of the species data. 7. These models reflect the coupling of local environmental conditions and the set of adaptations among the local taxa. These observations underscore the idea that habitat plays a major role in organizing stream assemblages. 8. Using these approaches, predictions can be made about the ability of various taxonomic groupings to track environmental change through time, or for projecting the impact of alternative land management scenarios. Identifying fundamental life history and other traits can improve the selection and evaluation of such indicators.

Joint analysis of stressors and ecosystem services to enhance restoration effectiveness

Abstract: With increasing pressure placed on natural systems by growing human populations, both scientists and resource managers need a better understanding of the relationships between cumulative stress from human activities and valued ecosystem services. Societies often seek to mitigate threats to these services through large-scale, costly restoration projects, such as the over one billion dollar Great Lakes Restoration Initiative currently underway. To help inform these efforts, we merged high-resolution spatial analyses of environmental stressors with mapping of ecosystem services for all five Great Lakes. Cumulative ecosystem stress is highest in near-shore habitats, but also extends offshore in Lakes Erie, Ontario, and Michigan. Variation in cumulative stress is driven largely by spatial concordance among multiple stressors, indicating the importance of considering all stressors when planning restoration activities. In addition, highly stressed areas reflect numerous different combinations of stressors rather than a single suite of problems, suggesting that a detailed understanding of the stressors needing alleviation could improve restoration planning. We also find that many important areas for fisheries and recreation are subject to high stress, indicating that ecosystem degradation could be threatening key services. Current restoration efforts have targeted high-stress sites almost exclusively, but generally without knowledge of the full range of stressors affecting these locations or differences among sites in service provisioning. Our results demonstrate that joint spatial analysis of stressors and ecosystem services can provide a critical foundation for maximizing social and ecological benefits from restoration investments.

The Theory of Island Biogeography

Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

Landscapes and Riverscapes: The Influence of Land Use on Stream Ecosystems

Abstract: ▪ Abstract Local habitat and biological diversity of streams and rivers are strongly influenced by landform and land use within the surrounding valley at multiple scales. However, empirical associations between land use and stream response only varyingly succeed in implicating pathways of influence. This is the case for a number of reasons, including (a) covariation of anthropogenic and natural gradients in the landscape; (b) the existence of multiple, scale-dependent mechanisms; (c) nonlinear responses; and (d) the difficulties of separating present-day from historical influences. Further research is needed that examines responses to land use under different management strategies and that employs response variables that have greater diagnostic value than many of the aggregated measures in current use. In every respect, the valley rules the stream. H.B.N. Hynes (1975)

The Environmental Protection Agency

Abstract: The Environmental Protection Agency (EPA) provides access to information on a variety of topics related to the environment and strives to inform citizens of health risks. The EPA also has an extensive library network that consists of 26 libraries throughout the United States, which provide access to a plethora of information to EPA employees, scientists, and researchers. The EPA implemented a reorganization project to digitize their materials so they would be more accessible to a wider range of users, but this plan was drastically accelerated when the EPA was threatened with a budget cut. It chose to close and reduce the hours and services of some of their libraries. As a result, the agency was accused of denying users the “right to know” by making information unavailable, not providing an adequate strategic plan, and discarding vital materials. This case study explores the background of the digitization project, the practices implemented, and the critiques of the project.

Mitigation and Adaptation Strategies for Global Change

Abstract: ▶ Addresses a wide range of timely environment, economic and energy topics ▶ A forum to review, analyze and stimulate the development, testing and implementation of mitigation and adaptation strategies at regional, national and global scales ▶ Contributes to real-time policy analysis and development as national and international policies and agreements are discussed and promulgated ▶ 94% of authors who answered a survey reported that they would definitely publish or probably publish in the journal again

The Soil and Water Assessment Tool: Historical Development, Applications, and Future Research Directions

Abstract: The Soil and Water Assessment Tool (SWAT) model is a continuation of nearly 30 years of modeling efforts conducted by the USDA Agricultural Research Service (ARS). SWAT has gained international acceptance as a robust interdisciplinary watershed modeling tool as evidenced by international SWAT conferences, hundreds of SWAT-related papers presented at numerous other scientific meetings, and dozens of articles published in peer-reviewed journals. The model has also been adopted as part of the U.S. Environmental Protection Agency (USEPA) Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) software package and is being used by many U.S. federal and state agencies, including the USDA within the Conservation Effects Assessment Project (CEAP). At present, over 250 peer-reviewed published articles have been identified that report SWAT applications, reviews of SWAT components, or other research that includes SWAT. Many of these peer-reviewed articles are summarized here according to relevant application categories such as streamflow calibration and related hydrologic analyses, climate change impacts on hydrology, pollutant load assessments, comparisons with other models, and sensitivity analyses and calibration techniques. Strengths and weaknesses of the model are presented, and recommended research needs for SWAT are also provided.