Thomas B. Hardy

Environmental consequences of alternative practices for intensifying crop production

The increasing global demand for food will be met chiefly by increased intensification of production. For crops, this will be achieved largely by increased yields per area with a smaller contribution from an increased number of crops grown in a seasonal cycle. Production systems show a spectrum of intensification practices characterised by varying methods of site preparation and pest control, and inputs of germplasm, nutrients and water. This paper highlights three main types of intensification (based largely on the quantity and efficiency of use of external inputs) and examines both the on- and off-site environmental consequences of each for soils, water quantity and quality, and climate forcing and regional climate change. The use of low amounts of external inputs is generally regarded as being the most environmentally-benign although this advantage over systems with higher inputs may disappear if the consequences are expressed per unit of product rather than per unit area. The adverse effects of production systems with high external inputs, especially losses of nutrients from fertilisers and manures to water courses and contributions of gases to climate forcing, have been quantified. Future intensification, including the use of improved germplasm via genetic modification, will seek to increase the efficiency of use of added inputs while minimising adverse effects on the environment. However, reducing the loss of nutrients from fertilisers and manures, and increasing the efficiency of water utilisation in crop production, remain considerable challenges.

The future of habitat modeling and instream flow assessment techniques

This paper examines emerging trends in applied instream flow assessment methods within the context of an ecologically based assessment framework, in light of the challenges imposed by the spatial and temporal domains of aquatic ecosystems. I will attempt to highlight what I consider to be the more promising technologies, modeling techniques and analysis approaches that represent workable tools to meet the needs of practical, applied instream flow assessments. To this end, I will touch on measurement techniques and technologies used to characterize the spatial domain of river systems, analysis tools for characterization of the hydrodynamic elements of rivers in both the spatial and temporal domains, and finally tools and approaches which integrate the biological elements at the individual, population and community levels. Much of my view of the future of habitat modeling remains an abstraction, in that integration of all the pieces has yet to be accomplished, field validation remains unproven, availability of an integrated analysis framework (i.e. computer software system) is not yet available, and a clear framework for selection and application of specific tools has not been developed. However, in presenting this particular view of the future, I hope to stimulate a broader collaborative effort between biologists, engineers and resource managers that continues to move the state-of-the-art forward. This effort should not consider the plurality of methods or analytical procedures as competing approaches, but rather as representing a tool-rich environment upon which researchers and practitioners can draw to provide scientifically based quantifications in support of management decisions which must protect and enhance our aquatic ecosystems.

AggieAir — a low-cost autonomous multispectral remote sensing platform: New developments and applications

Data acquired by aircraft, satellites and other sources of remote sensing has become very important for many applications. Even though current platforms for remote sensing have proved to be robust, they can also be expensive, have low spatial and temporal resolution, with a long turnover time. At Utah State University (USU), there is an ongoing project to develop a new small, low-cost, high resolution, multispectral remote sensing platform which is completely autonomous, easy to use and has a fast turnover time. Many new developments have been added to AggieAir which have improved the flight performance and flexibility, increased the flight time and payload capacity. Furthermore, these developments have made it possible to carry an imaging system with more quality and resolution. With these new developments, AggieAir has begun work with many projects from areas in agriculture, riparian habitat mapping, highway and road surveying and fish tracking. Development on AggieAir continues with future plans with a thermal inferred camera, an in house iner-tial measurement unit (IMU) and better navigation to handle higher winds.

Using a multispectral autonomous unmanned aerial remote sensing platform (AggieAir) for riparian and wetlands applications

An autonomous, unmanned, aerial, remote sensing platform called AggieAir™ has been developed at Utah State University (USU) to produce multispectral aerial imagery. Its independence of a runway, low cost, and rapid turn-around time for imagery make it an efficient platform for applications in riparian areas and in wetlands management. Using third-party software, the imagery from AggieAir can be stitched together into mosaics, georeferenced, and used to classify vegetation and map riparian systems, substrates and fish habitat for hydraulic modeling, river morphology and restoration monitoring. Likewise, the multispectral mosaics can be used to monitor changes in meso-scale aquatic habitat features and invasive/native plant species, as well as delineate different types of wetlands for wetlands management. This paper introduces AggieAir and highlights some of the projects in riparian and wetlands applications in which it has been involved. AggieAir has also been involved with agricultural and biofuel applications.

Prediction of fisheries physical habitat values based on hydraulic geometry and frequency distributions of depth and velocity

Abstract We propose a technique that allows the estimation of available physical fish habitat in small sized stream reaches (mean annual flow less than 3.5 m3/s) without the need to acquire and analyze extensive site‐specific data commonly used in many instream flow studies. The technique utilizes a modified form of previously published equations that estimate velocity and depth frequency distributions based on reach average velocity and depth which in turn can be calculated using widely known at‐a‐station hydraulic geometry equations. Velocity and depth frequency distributions are then combined with fish preferences for velocity and depth to produce habitat versus discharge relationships for a desired range of flows. When the resulting physical habitat versus discharge relationships for target fish species and life stages are compared to weighted usable area relationships (habitat versus discharge relationships derived using hydraulic and habitat models) developed from site‐specific studies, the prediction error was shown to be less than 15%.

Validation of Chinook fry behavior‐based escape cover modeling in the lower Klamath River

Abstract An emerging trend in the state‐of‐the‐art instream flow assessment applications is the use of three‐dimensional channel topography coupled with two‐dimensional hydrodynamic models. These components are most often integrated with biological response functions for depth, velocity, and substrate to simulate physical habitat for target species and life stages. These approaches typically involve the simple extension of the one‐dimensional conceptual habitat models represented by the Physical Habitat Simulation System (PHABSIM) developed by the U.S. Fish and Wildlife Service (Stalnaker, 1995). However, as demonstrated in this paper, the physical habitat based template represented by high‐resolution channel topography and two‐dimensional hydrodynamic model outputs can extend these simple conceptual models of habitat to incorporate additional behavior‐based decision rules. The approach demonstrated in this paper evaluates the spatial suitability of physical habitat for chinook fry based on the incorporation of behavioral rule sets associated with instream object cover (i.e., velocity refuges) and in‐water escape cover type and distance. Simulation results are compared to simplistic based physical habitat simulations using only depth, velocity, and substrate and validated against independent fish observation data. Results demonstrate that the functional relationship between predicted habitat and discharge utilized in many instream flow assessments is significantly different when the additional behavior‐based decision rules are applied.

Movement and Microhabitat Associations of Guadalupe Bass in Two Texas Rivers

Abstract The Guadalupe bass Micropterus treculii is endemic to Texas and is threatened by introgression with introduced smallmouth bass M. dolomieu as well as habitat degradation. This study described and quantified the movements and habitat associations of Guadalupe bass to assess the factors that may influence current populations. Radio-tagged adult Guadalupe bass were tracked in the Pedernales River (n = 12) and South Llano River (n = 12) from January through August 2008. Available microhabitats were measured and modeled in terms of depth, velocity, substrate, and cover for about 1.5 km in the Pedernales River and 1.2 km in the South Llano River. Rates of movement were greatest during the reproductive season, ranging from less than 1 to 9 m/d. Instream cover (such as undercut banks and woody debris) was preferred during daylight hours throughout the study period, although the distances from cover increased from January to August. Habitat shifts from cover to open water occurred at night and from woody ...

Using Multiple Open-Source Low-Cost Unmanned Aerial Vehicles (UAV) for 3D Photogrammetry and Distributed Wind Measurement

Small, low-cost unmanned aerial vehicles (UAV) has made data acquisition more convenient and accessible for many applications. Using multiple UAVs (a coven) brings even more advantages like redundancy and distributed information. The objective of this paper is to show how a coven of UAVs can help two applications: measuring wind and 3D photogrammetry.Copyright

Extrapolation of site‐specific weighted usable area curves and instream flow requirements to unmeasured streams within the Nooksack watershed in support of strategic watershed planning

Abstract Given the large number of locations within the study watershed (Washington, USA) where instream flow information is required, a GIS based stratification procedure using multivariate data analysis techniques was developed to extrapolate either instream flow recommendations or habitat availability curves (weighted usable area curves) upon which instream flow recommendations could be developed from study sites to other sites where no site‐specific information is available. One‐hundred‐seventy‐two drainages were divided into 21 hydrologically and geomorphologically similar subgroups. Mean annual flow versus drainage area and 60% exceedence flow versus drainage area relationships were also developed for the study area. Monthly instream flow recommendations were then extrapolated to the unmeasured streams within the hydrologically and geomorphologically similar subgroups by scaling them by a percentage of the mean annual flow; weighted usable area curves were extrapolated to the unmeasured streams within the same subgroups by scaling the flows by a percentage of the 60% exceedence flow. Extrapolated monthly instream flow recommendations ranged between 0 and 76 percent but were generally within about 20 percent or less when compared to recommendations developed from site‐specific analyses. Extrapolated weighted usable area relationships had an average root mean square error less than about 17% and reflected the basic functional relationships when compared to site specific analyses. This study demonstrates that either instream flow recommendations or weighted useable area relationships derived from site‐specific data can be extrapolated to unmeasured sites for use within the context of strategic watershed planning based on the development and application of two extrapolation methodologies.

Instream Flow Assessment Modelling: Combining Physical and Behavioural-Based Approaches

Most state-of-the-art applications of habitat modelling rely on three-dimensional channel topography and two-dimensional hydrodynamic models that have centered on the simple extension of one-dimensional physical habitat-based concepts (i.e., extension of the Physical Habitat Modelling System - PHABSIM). However, as demonstrated in this paper, these approaches can be extended to more realistically incorporate both the physical habitat-based metrics of streamflow and behavioural decision rules that can incorporate fish community structure and dynamics. This approach evaluates the spatial suitability of physical habitat-based on the incorporation of behavioural rule sets, such as the association with escape cover type and distance, exclusion zones associated with predators or linear dominance hierarchies, and lag-time dependence of macroinvertebrate re-colonization of habitats associated with varial zones induced by peaking/load following operations of hydropower facilities. In the paper we lay the foundation between field data collection strategies for characterization of the physical domain, and modelling the hydraulic properties of flow using two- or three-dimensional hydraulic models. We then describe the use of GIS for the integration of additional factors such as substrate, cover, distance to cover and distance to water’s edge factors. We then demonstrate how GIS, in conjunction with decision based habitat algorithms, can be used with classical-based physical habitat modelling to incorporate behavioural-based rules to evaluate escape cover, exclusion zones and lag-time dependence for macroinvertebrate under variai zone induced impacts. These examples are based on results from studies in regulated river systems in which these techniques have been shown to improve the assessment of impacts/benefits associated with altered flow regimes.