Past Seminars & Discussions

Subject Population Modeling

Video

The Ecology and Conservation of Jaguar in Western Paraguay

Abstract

The jaguar is the largest cat in the Americas, found from the southwestern United States southward into Argentina. The Gran Chaco and Pantanal ecosystems in western Paraguay support one of the few population strongholds but are subject to increasing anthropic pressures. My collaborators and I have documented that the largest jaguar home ranges occur in western Paraguay which indicates that conservation of the species in the region is highly dependent upon private ranch land. We have also found from large-scale camera trap sampling that jaguar densities are negatively affected by increasing deforestation. Furthermore, opportunistic or retaliatory killing of jaguars in response to livestock depredation are principal causes of mortality for the species in the region. Although jaguar exhibit tolerance to habitat loss and prey depletion in western Paraguay, their large spatial needs illustrate a critical need to mitigate the killing of jaguars in the region if a viable population of jaguar is to be maintained in western Paraguay over the long term.

Applied Ecology and Management Around Waterfowl Management in Nebraska

Abstract

Ornithologists have been banding birds for over a century, but these data have been used less often than they could be to answer questions about population dynamics. In this seminar, I attempt to bridge the gap between data-rich species like mallards (Anas platyrhynchos), with over 1.2 million band recoveries, to data-poor species like wood warblers (Parulidae), with just over 6,000 recoveries from 53 combined species. The most common application of band-recovery data is estimation of annual survival. By using species as random effects, I show how we can also estimate juvenile and adult survival for data-poor assemblages such as wood warblers. Moving on to fecundity, I demonstrate how we can estimate fecundity at annual and regional scales using age ratios of birds captured for banding, and I apply these estimators to prairie dabbling ducks (Anatidae) and dark-eyed juncos (Junco hyemalis). Finally, I demonstrate how banding data can be combined with harvest data to estimate population size using Lincoln estimators, and apply the method to data-rich and data-poor examples.

Video

Data-driven Modeling of Ecological Dynamics

Abstract

Systems that exhibit complex, nonlinear, and even chaotic dynamics can be challenging to understand and model. In particular, unlike physics or chemistry, biology does not have fundamental mathematical laws, and many of the quantitative relationships (e.g. scaling laws) are empirical rather than proscriptive. In this presentation, two examples that apply the framework of empirical dynamic modeling to infer mechanism directly from time series are examined: (1) elucidating the role of environmental conditions for recruitment of Fraser River sockeye salmon; and (2) identifying causal drivers and algal blooms in the Southern California Bight. I conclude with an overview of current work to quantifying long-term change in complex ecological communities.

Video

Earth observation by constellations of CubeSats: New opportunities and challenges

Abstract

Emerging satellite constellations comprised of hundreds of small CubeSats are transforming very high-resolution earth observation by overcoming the spatiotemporal constraints associated with conventional single-sensor satellite missions. However, the large number of constellation satellites, and relatively cheap sensor components and design, introduce cross-sensor inconsistencies and cross-calibration challenges. While superior in terms of spatiotemporal resolution, the radiometric quality, spectral resolution, and absolute calibration accuracy is not equivalent to that of rigorously calibrated space-agency satellites such as Landsat and Sentinel. A CubeSat Enabled Spatio-Temporal Enhancement Method (CESTEM) has been developed to realize the full potential of CubeSat sensing. CESTEM adopts an agnostic sensor data fusion and cross-sensor calibration technique that exploits conventional satellite systems as the gold standard. CESTEM offers a unique data-driven avenue towards cross-platform interoperability enabling spatiotemporal enhancement of spectral metrics and biophysical properties retrievable from conventional large satellite systems. In this work, CESTEM ingests high quality Landsat 8 and Sentinel-2 based retrievals of surface reflectance and plant biophysical properties as references to calibrate relatively noisy CubeSat observations and provide high fidelity CubeSat-based insights into crop growth dynamics, developing plant stress, and crop disturbances. Using CESTEM, daily 3 m RGB and NIR imagery afforded by a constellation of ~150 active CubeSats deployed in low-earth orbits, are transformed into Landsat 8 or Sentinel-2 consistent surface reflectance and leaf area index estimates. Application over a variety of agricultural landscapes and environments highlights the resolution advantage both spatially and temporally. Comparisons against in-situ observations in fields of corn near Mead, Nebraska demonstrate encouraging capability of the CESTEM-based estimates for reproducing observed spatiotemporal dynamics. The repeatable in-field information on crop condition provided by CESTEM have significant potential for powering smarter, more efficient, and productive farming at broad scales.

Video

A river on trial: Assessing stream health in an agro-urban landscape

Abstract

Streams and rivers provide many ecosystem services to humans, including water filtration, flood protection, and recreation among other benefits. In the agricultural Midwest, the impact of human land-use can degrade these freshwater ecosystems and limit their ability to deliver the same degree of services as streams flowing through watersheds with more natural land-use, such as prairies or forests. The Raccoon River is a socially and economically important river in Central Iowa. However, the high nitrate loads led the Des Moines Water Works to bring a lawsuit against upstream drainage districts over the river's water quality. My recent research has explored the variation in nitrate export and loss within the Raccoon River across space and through time. In addition, we have investigated the ecological value of land conservation as reflected by stream ecosystem function. Together, these studies seek to inform the management of river and streams in human-dominated landscapes.

Video

The roles of interest, career goals, and response to challenge in student persistence; a micro- and macroscopic view

Abstract

Numerous calls for reform in undergraduate biology education emphasize the need for more biology graduates who have skills in and exposure to “science practices” such as research. In addition, there is a national need for more students to complete STEM degrees and fill positions in research-based fields. Conducting scientific research is recognized as one of the most challenging endeavors, requiring strong interest, creativity, perseverance, and the desire to actively engage with novel and unknown challenges. These aspects cannot be taken for granted as time and practice are needed to develop such motivations and dispositions. This talk will focus on investigations of two important student dispositions that contribute to persistence in research-based STEM endeavors: interest and perseverance during setbacks. The first half will address how strong interest in biology drives students’ engagement with extracurricular disciplinary experiences (e.g., research, clubs, or internships) that are often key in affording access to graduate school. This study takes a qualitative approach to examine the role of interest and career goals in students’ engagement with and access to such experiences over the entirety of their undergraduate career. The second half will zoom-in to explore how students’ responses to research setbacks affect persistence and learning during research-based tasks in a laboratory environment. This study examines the various ways in which students cope with research challenges and whether we can predict coping strategies based on student background. By working at the macro- and micro-level, this research program hopes to develop an overarching understanding of how students become engaged, resilient researchers.

Video

Penguins in the Mist: Tales of Transformation on an Antarctic Journey for Women in STEMM

Abstract

Globally, women have the potential to bring something new to the table when it comes to making decisions about sustainability and environmental change. But what does it take to bring more women into the roles of decision makers? Homeward Bound (HB) is a major international initiative aimed at empowering women to step into leadership roles where they can make a difference. Specifically, the program supports women in STEMM in the areas of leadership development, strategic planning, and visibility, all in the context of the science of global climate change. Antarctica, one of the most fragile places on the planet, serves as the backdrop for this work in learning, connecting, and dreaming up ideas for a better world. In this talk you’ll get a peek at the HB professional development program and hear the story of the third HB journey to the Antarctic Peninsula in January 2019. You’ll see photos of penguins, whales, and icebergs, and hear stories about the women of HB and what they hope to do together. You’ll also learn how you can be a part of this as a scientist and/or as someone concerned about the future of the planet.

Adventures in Deciphering Weather and Climate Change in the Ecuadorian Andes

Abstract

The paramo is a broad grassland above 3000 meters in elevation that stores rainwater for more than 300 thousand people in the city of Cuenca, Ecuador. Despite the importance of this region to the water supply, weather records only date back to 2013, so it is difficult to know whether perceived changes in rainfall are a threat to this region. Most weather and climate models inadequately capture patterns of atmospheric circulation in this region. In this talk, I share my experiences in Ecuador working with colleagues at the University of Cuenca to interpret weather observations from a new network of stations positioned along an altitudinal gradient from the city of Cuenca (2500 m) to the UNESCO Biosphere Reserve of El Cajas National Park (4400 m). As a first step, we measured lapse rates in this region to improve mapping of temperatures by models. Additional work has examined evaporation rates in the páramo and made attempts to use the Weather Research and Forecasting Model (WRF) to understand observed rainfall patterns. To expand meteorological expertise among scientists in the region, a part of my work also involved developing of a graduate course and a field camp in meteorology for young investigators and sharing teaching strategies with colleagues through seminars and workshops. Together, we developed an educational model that could be employed in other regions of the world to build expertise in understanding impacts of changing environments.

Interactions of Landscape Structure and Management of Northern Bobwhites