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Yellowstone National Park, 2021

AJ Enriquez and DC Finnoff (2021). Managing mortality of multi-use megafauna.
Journal of Environmental Economics and Management 107: 102441.



Greater Yellowstone Ecosystem grizzly bears, which are currently federally protected under the Endangered Species Act, are a high-profile multi-use species. As the number of grizzly bears has increased, there have been increases in the number of grizzly bear-human conflicts and human-caused grizzly bear mortalities. A bioeconomic model is constructed in which a representative wildlife agency considers these relationships and maximizes discounted social net benefits by deciding whether to enact direct population control. A linear specification is employed to reflect the realities of negotiated and rigid active management programs. The agency accounts for how stock-dependent benefits and damages adjust along the recovery path, which tracks the natural capital value of a live grizzly bear as the population changes over time. Benchmark results indicate that the grizzly bear population has surpassed the size at which protections ought to have been removed. The natural capital value of an additional animal in the wild, given by its in-situ marginal net benefits, may actually be negative for an interval of time, during which it is optimal for society to continue conserving the species by developing a buffer. The results of the analysis are sensitive to key economic and ecological parameters, especially on the benefits side.


DA Bagdonas, AJ Enriquez, KA Coddington, DC Finnoff, JF McLaughlin, MD Bazilian, EH Phillips, and TL McCling (2022). Rare earth element resource evaluation of coal byproducts: A case study from the Powder River Basin, Wyoming. Renewable and Sustainable Energy Reviews 158: 112148.



Rare earth element sources and production are limited in the United States and currently rely on final processing overseas. Increasing demand and resource security has led to significant investigation into domestic rare earth elements. Much of this work focuses on unconventional potential ore stocks, including coal and coal byproducts. This investigation focuses on coal byproducts generated as ash from coal-burning power stations. Wyoming’s Powder River Basin hosts the largest U.S. coal stocks for energy production, providing approximately 40% of all thermal coal mined in the U.S. In Section I, we study coal byproducts for rare earth element concentrations and compare these data to current alternative resource knowledge. We find that coal byproducts are consistently high enough in rare earth element concentration (above the current Department of Energy 300 ppm cutoff grade) to warrant consideration as a promising potential resource. Rare earth element behavior within the host coal seams is also considered in an effort to better understand resource prospecting and ore body description. In Section II, we evaluate the economic feasibility of rare earth extraction from Powder River Basin coal byproducts using net present value analysis and the rare earth concentrations data from Section I. We calculate the break-even ash-to-oxide output and input unit costs for four coal stations in the Powder River Basin. All four stations have break-even unit costs that are higher than the mine-to-oxide operating cost reported for a traditional rare earth element mine. This is a promising result, especially given that it is more costly to refine rare earths from mined material than from ash. The results are highly sensitive to rare earth prices: given low long-term prices, none of the stations can feasibly break even. Section III summarizes federal policy considerations in rare earth element resource development. The history of policy development, most recently focused on rare earth element-specific funding legislation, paired with the results from Sections I and II herein, suggest a robust opportunity for the development of Wyoming-based coal byproducts as a partial solution to current domestic rare earth element shortfalls and strategic needs.

Papers Under Review

Valuing wildlife sightings at the species-wide and individual animal levels:
An approach and application to bear viewing in Yellowstone National Park

LA Richardson and AJ Enriquez

Status: Under review (revised and resubmitted)


Wildlife viewing is a highly demanded recreation activity in protected areas, yet species-specific information on the economic value of wildlife sightings, and how that value is affected by small-scale population changes, is lacking. This makes it challenging to answer key wildlife management questions, like how to estimate damages from the loss of an individual animal. We present a general approach to fill the gap. First, we estimate a travel cost model to obtain the per capita value of a day spent viewing wildlife. We link the resulting estimate to the probability of viewing an animal, which allows us to derive economic value from wildlife sightings both at the species-wide and individual animal levels. We apply our approach to bear viewing in Yellowstone National Park. Results indicate aggregate annual values of $6.8 and $8.6 million for viewing grizzly and black bears, respectively, with corresponding per-bear values around $46,000 and $15,000.

The pain of paying with other people's money
AJ Enriquez, BT Gilbert, and LH Thunström

Status: Under review (submitted)


Spending decisions are at the heart of consumer research, and factors that impact spending have been studied for decades. The literature has focused on spending decisions based on self-earned money, but people often spend money that was earned by someone else (e.g., partners spend each other’s earned money, government officials spend tax payer money, employees spend employer money, people in need spend social benefits). We focus on the shortest social distance between consumer and earner - intra household spending - and survey 161 couples to examine how pain of paying depends on the source of the money. We find that people feel higher pain of paying when spending money earned by their partner than when spending self-earned money. People's pain of paying increases if they believe their partner will be unhappy with their purchase, and their ability to accurately predict their partner's feelings about the purchase increases with partner similarity in spendthriftiness. Pain of paying regulates consumer spending: the higher the pain, the lower the spending.

What ticks people off? Linking perceived risk, self-protection actions, and economic attributes.
AJ Enriquez, K Berry, M Fernandez, N Gregory, KC Ernst, MH Hayden, and M Diuk-Wasser

Status: Under review (submitted)


There are increasing health threats from ticks, including in urban environments with green spaces. We administered a household survey about perceived risks from ticks on Staten Island, a New York City Borough where the combination of high population density and extensive park systems has resulted in a rise in locally-acquired tick-borne disease cases. We first analyze what drives people’s perceptions of different types of risks, including exposure to ticks and infection with Lyme disease. Prior risk experience correlates strongly with higher perceived risk, which is potentially problematic in a location where threats are newly emerging. Next, we examine the correlation between perceived risks and counts of past self-protection actions. Avoidance behaviors are driven by high levels of both perceived risk of exposure and infection. Mitigation behaviors, on the other hand, are driven only by perceived risk of exposure. Finally, we use stated preference questions to test what influences people’s future “willingness to spray” tick pesticide, across a range of economic attributes including cost, effectiveness, and type (organic versus synthetic). High levels of perceived risk make individuals more likely to spray, but economic variables also play a critical role. A multidisciplinary approach is therefore appropriate when promoting community-based control strategies to protect human health in new transmission contexts.


"Balancing commercial and 'personal use' salmon fishing." Seminar at the Stockholm Resilience Centre. November 2022 in Stockholm, Sweden.

“Characterizing the conservation culture for charismatic critters.” Association of Environmental and Resource Economists Summer Conference. June 2022 in Miami, Florida.

“Grizzlies in the Greater Yellowstone Ecosystem: Bioeconomic analysis and nonmarket valuation.” Seminar at the Institute of Social and Economic Research. November 2021 in Anchorage, Alaska.


“The economic value of wildlife tourism and implications of marginal population changes.” BIOECON XXII Annual Conference. September 2021 in Jackson, Wyoming.


“Bioeconomic grizzly bear management.” University of Wyoming-Colorado State University Graduate Student Symposium. April 2019 in Laramie, Wyoming.


“From the shore or from the water? Enforcement of resource rights under discrete enforcement technologies.” International Institute of Fisheries Economics & Trade Biennial Conference. July 2018 in Seattle, Washington.


“Economic feasibility of rare earth element extraction from Wyoming coal ash/char.” Geological Society of America Annual Meeting. September 2016 in Denver, Colorado.

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