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Economic Currents

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Hybrid Forest Restoration Benefits Communities and Increases Resilience

Photo by Ben Nyberg

Researchers from UHERO, the University of Hawai`i at Mānoa, and National Tropical Botanical Garden quantify social, ecological, and economic costs and benefits of alternative forest restoration strategies

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An interdisciplinary research team from the University of Hawai`i at Mānoa (UHM) and the National Tropical Botanical Garden (NTBG) demonstrated how collaboratively-developed forest restoration in Limahuli Garden & Preserve (Limahuli) can increase community benefits and improve resilience at lower cost than standard forest restoration programs. Because conservation managers are increasingly faced with making restoration decisions constrained by multiple goals and limited budgets, the research team collaborated with conservation professionals at Limahuli to co-design research that will directly inform adaptive management.

Specifically, authors of a newly published study in the journal Conservation Letters asked how manager-defined ecological, hydrologic and cultural metrics of success and long-term management costs vary across different restoration strategies. The researchers focused on the ahupua`a of Hā`ena on Kaua`i Island, and evaluated unrestored forest and forests restored to different states—ranging from a pre-human arrival state, to a “hybrid” state that includes mixes of native and non-native species of cultural importance. Their study site was Limahuli Valley, a 400-hectare nature preserve managed by NTBG in the most biodiverse ecoregion of the Hawaiian archipelago, which is home to dozens of endangered plants and birds found nowhere else on earth. They found that restoring forest to a hybrid state provided many of the same services that a restored ‘pre-human’ state can provide, but at a much lower cost. They also found it increased two important services: cultural value and resilience to disturbance such as hurricanes.

The paper “Restoring to the Future: Environmental, Cultural, and Management Tradeoffs in Historical versus Hybrid Restoration of a Highly Modified Ecosystem” has a diverse team of authors from the natural and social sciences as well as natural resource managers: Kimberly M. Burnett, Tamara Ticktin, Leah L. Bremer, Shimona Quazi, Cheryl Geslani, Christopher A. Wada, Natalie Kurashima, Lisa Mandle, Pua`ala Pascua, Taina Depraetere, Dustin Wolkis, Merlin Edmonds, Thomas Giambelluca, Kim A. Falinski, and Kawika B. Winter.

“Restoring forests to a pre-human state on a landscape scale has been idealized, but—given the amount of functional diversity that has gone extinct in Hawai`i—such an approach is almost impossible, ecologically speaking. Beyond that, our research has shown that goal is economically impractical, and it isn’t the best way to engage community in restoration efforts,” said Dr. Kawika Winter, a multidisciplinary ecologist and Research Associate at NTBG who is the anchor author of the new study. “These results can be used by conservation practitioners to guide management actions, and to bring the community back into the forest while improving multiple ecological and social benefits; and do all this at lower costs than programs focused solely on historical restoration goals.”

The methods also have applications far beyond Hawai`i, particularly as conservation managers working in places with a history of cultural engagement with forests, and who are increasingly faced with decisions on how to fund and approach restoration efforts. This new research provides a framework to help managers identify restoration strategies addressing multiple goals in regions where restoration is challenging – areas where invasive species or other issues limit natural regeneration of native species, and/or where local populations depends on natural resources. Lower costs also offer the possibility of scaling-up, a critical consideration since island conservation is underfunded compared to continents.

Dr. Kimberly Burnett, Specialist with the University of Hawai`i Economic Research Organization and lead author of the study, said: “While conservation managers cannot make realistic decisions without considering costs, these type of tradeoff analyses are rare in restoration research. Our study provides a framework to consider these costs and benefits, while providing specific management direction for Limahuli and generalizable lessons for restoration strategies around the world.”

Dr. Tamara Ticktin, co-author on the study, Professor of Botany at UHM, and Principal Investigator on the National Science Foundation grant that funded the research, added: “Like any restoration strategy, hybrid forest restoration also has its limitations. Our study concluded that hybrid forests can be an excellent strategy within a landscape mosaic that also includes more expensive restoration strategies needed to preserve the most endangered species. The value of our multidisciplinary approach is that it provides a powerful tool for resource managers to take into consideration the different metrics that are important to them, and to make more informed decisions about what that landscape mosaic of restored forest could look like.”

This study was supported through funding from a National Science Foundation grant to the University of Hawai`i.


Vog: Using Volcanic Eruptions to Estimate the Health Costs of Particulate

Posted August 20, 2018 | Categories: Hawaii's Environment, Blog

Since its inception, the Environmental Protection Agency (EPA) in the United States has proven itself to be effective at reducing air pollution. For the six ‘criteria’ pollutants that the EPA is mandated to regulate, emissions of all six have declined substantially. Particulates have declined by 38% since 1990. Furthermore, large reductions in particulate pollution in the 1970s have been shown to be a direct effect of EPA regulation. Now that air pollution in many parts of the US has declined significantly, an important policy question becomes how much further reduction is desirable.

Understanding the optimal level of air pollution is critical to setting the National Ambient Air Quality Standards or NAAQS. However, doing so is hampered by two challenges. The first is that, while the costs of pollution abatement are straight-forward to measure using units such as kilowatts of energy or laptops produced, the benefits are harder to quantify. Randomized trials are not an option because it is unethical to deliberately expose people to toxic air pollution. The second challenge is that while the NAAQS correspond to one pollutant (e.g. carbon monoxide or sulfur dioxide), most sources of pollution emit many pollutants at once. As a result, identifying the costs of any one pollutant is very difficult as any given pollutant is confounded by others. Assigning blame to particulates then becomes a challenge. In fact, many academic studies that look at the effect of particulates alongside other pollutants find that particulates have no effect on health outcomes. One way to address these two challenges is to find a ‘natural’ experiment – a situation where the general public has been randomly exposed to pollution and, specifically particulates, in a way that mimics an actual experiment.

The largest stationary source of sulfur dioxide pollution in the US is Kīlauea volcano located on the island of Hawai`i. This sulfur dioxide reacts with sunlight, oxygen, dust and water in the air to produce ‘vog’ (volcanic smog) which is one species of particulate pollution. The Hawaiian Islands typically have some of the best air quality in the world. But whenever Kīlauea volcano starts emitting gases and trade winds die down, the state’s 1.4 million residents experience short-term exposure to elevated levels of particulates. Particulates are far-and-away the main pollutant in the State of Hawai`i and they are very weakly correlated with other pollutants unlike other sources of particulates such as coal-fired power plants.

In a recent paper, we leverage volcanic emissions from Kīlauea over the period 2000-2012 to estimate the causal impact of particulates on emergency room (ER) admissions and charges. We employ measurements of air quality taken from various monitoring stations across the state and administrative data on ER utilisation due to pulmonary-related reasons. An important feature of our study is that our cost data are more accurate than the cost measures used in much of the literature. We isolate variation in particulate pollution on the island of Oahu (which is to the northwest of the island of Hawai`i) that is the consequence of emissions from Kilauea and wind direction to estimate the health costs of particulates.

We find strong evidence that daily exposure to particulate pollution increases pulmonary-related ER admissions. Our instrumental variables estimates indicate that one standard deviation increase in particulates on Oahu increases ER charges for pulmonary-related reasons by 25-35%. These effects are mostly concentrated among the very young. We provide evidence of harm due to particulate pollution below the NAAQS.

- Tim Halliday, John Lynham, and Aureo de Paula

UHERO BLOGS ARE CIRCULATED TO STIMULATE DISCUSSION AND CRITICAL COMMENT. THE VIEWS EXPRESSED ARE THOSE OF THE INDIVIDUAL AUTHORS.


Makena Coffman appointed to Climate Change Commission

UHERO congratulates Makena Coffman on her appointment to Honolulu's Climate Change Commission. The goal of the commission is to assess potential impacts of climate change on Hawaii, and to provide policy makers with recommendations to address these impacts.

Makena Coffman is the co-director of Project Environment, UHERO Research Fellow, and Professor of Urban and Regional Planning.


Bringing multiple values to the table in local decision making – NSF Coastal SEES

“Want to carry one up?” the natural resource management team with Limahuli gardens in Haʻēna, Kauaʻi asks us as they hand out potted endangered plant seedlings before our hike up the trail toward one of their native forest restoration areas. We arrive 30 minutes later to the first restoration plot and are amazed to see an oasis of diverse native plants in a broader sea of mostly non-native forest. Restoration like this provides many benefits including biodiversity, cultural value, watershed protection, but it can also be expensive. Limahuli gardens, like so many natural resource managers around the State, face decisions around where and how to invest limited conservation resources. In an effort to cost-effectively restore a larger area of forest that provides a suite of ecological and cultural (ie biocultural) benefits, managers at Limahuli are pioneering careful consideration of multiple restoration strategies, including hybrid restoration with native and culturally useful non-invasive introduced species.

Limahuli restoration area

On the other side of the Hawaiian Islands, we have the rare opportunity to spend time in the Kaʻūpūlehu dry forest restoration project in North Kona, Hawaiʻi Island, a highly successful community-based effort to restore the most threatened ecosystem in the world. Many of the community members who work here are from cattle ranching families. They see tremendous value in mixed use landscapes including native forest and pasturelands, but worry about encroaching urban development. In this context, landowners across the State, including Kamehameha Schools, face decisions about the future of pasturelands, including the right mix of continued pasture, forest restoration and other land use options like coffee or restoring to agroforestry (a once prominent land use in the region).

NSF Coastal SEES team members Tamara Ticktin and Shimona Quazi enjoy the smell of blooming Aiea plants in the Kaʻūpūlehu dry forest.

Measuring keiki recruits in the stewarded dry forest.

Pasture bordering forest in high elevation areas in Kaʻūpūlehu

Real-world decision contexts like these have spurred a growing body of research striving to shine light on the ways that land management decisions influence societal well-being. Huge strides have been made to operationalize inclusion of the ‘value’ of land into decision making. Yet, this body of work largely remains siloed between those focusing on the biophysical and monetary values and those focusing more broadly on socio-cultural values. This division precludes a pluralistic set of values being included in decision-making in a meaningful way.

Over the past 3 years, UHERO, through an NSF Coastal SEES project – “Linking local ecological knowledge, ecosystem services, and community resilience to environmental and climate change in Pacific Islands”—has been part of a transdisciplinary team of researchers who have worked closely with landowners and communities in several study sites, including Haʻēna and Kaʻūpūlehu to bridge this divide.

In Haʻēna we worked alongside Limahuli reserve manager, Kawika Winter and his staff, to explore the costs and benefits of 3 restoration strategies: 1) restore to a state before rats were introduced (pre-rat); 2) restore to a pre-European state; and 3) restore using a mix of native and culturally useful non-invasive introduced species (hybrid scenario). Within each scenario, we evaluated the restoration costs alongside the benefits in terms of native and endemic species of plants restored, resilience (measured by functional diversity), and cultural value of plants restored. Cultural value was assessed based on a framework of past and current use based on community workshops and the long-term experience of managers working in the area. Interestingly, we found that the hybrid scenario provides important ecological benefits in terms of restoring a resilient mix of native species while also supporting a variety of culturally useful plants at a cost much lower than the other restoration strategies. While conservation of endangered species requires additional strategies, hybrid restoration offers a cost-effective way of scaling up restoration that can also provide important cultural and community benefits.

Variation in environmental and cultural benefits across three different restoration scenarios.

In Kaʻūpūlehu, we worked alongside Kamehameha Schools and the Kaʻūpūlehu community to evaluate potential futures of pastureland. We considered the management costs and environmental (biodiversity, groundwater recharge, fire risk), cultural, and economic outcomes of four future land use scenarios on a large cattle ranch: 1) retain pasture; 2) restore native forest; 3) restore agroforest; and 4) convert to coffee. Unsurprisingly we found that no one land use was the best on all metrics assessed, and that cultural value (assessed using participatory, deliberative methods and an indigenous cultural values framework) was very high in all land uses except for coffee (which is not an important land use in the immediate area). Similar to Haʻēna, we found that the agroforestry scenario (a hybrid forest) offered the greatest potential in terms of multiple benefits, including economic return. Yet, it is pasture which currently provides some of the highest cultural value in terms of local knowledge and cultural connection to place. Rather than providing clear answers to Kamehameha Schools about the “best” way forward, our research provided a way to bring multiple values, including cultural and environmental values, to the table in a concrete way.

Tradeoffs and synergies among different values with land use options in North Kona.

Integrating and including diverse values into decision-making is challenging, but critically needed around the world. We see no better place than Hawaiʻi to continue to work with on-the-ground managers to move this forward to contribute to more sustainable and resilient decisions. As an extension of our work in Kaʻūpūlehu and Haʻēna, we are now collaborating with a local non-profit Kakōʻo ʻŌiwi in Heʻeia Oʻahu to consider the multiple benefits of loʻi restoration through time. More to come!

Note: The NSF Coastal SEES project Principal Investigators were: Tamara Ticktin (UHM Botany), Kim Burnett (UHERO), Alan Friedlander (UHM Biology and National Geographic), Tom Giambelluca (UHM Geography), Stacy Jupiter (Wildlife Conservation Society -Fiji), Mehana Vaughan (UHM NREM), Kawika Winter (National Tropical Botanical Garden), Lisa Mandle (Natural Capital Project, Stanford), and Heather McMillen (NREM). Special thanks also to project researchers and graduate students who carried out much of this work, including Puaʻala Pascua, Shimona Quazi, Natalie Kurashima, and Christopher Wada. Finally, we are grateful to our community and landowner partners in Kaʻūpūlehu and Haʻēna who made this project possible.

- Leah Bremer 
UHERO and Water Resources Research Center Assistant Specialist

UHERO BLOGS ARE CIRCULATED TO STIMULATE DISCUSSION AND CRITICAL COMMENT. THE VIEWS EXPRESSED ARE THOSE OF THE INDIVIDUAL AUTHORS.


Cost-Effectiveness of Herbicide Ballistic Technology to Control Miconia in Hawaii

UHERO is working with Dr. James Leary (CTAHR) to assess cost effectiveness of Herbicide Ballistic Technology (HBT) operations to control invasive miconia (Miconia calvescens) plants before reaching maturity. Based on studies in Costa Rica, Tahiti and Australia, we can interpret spatial and temporal implications of management driven by miconia’s fecundity, dispersal, seed bank longevity and recruitment. We find that the dispersal kernel of miconia in the East Maui Watershed is closely matched to a similar probability density function developed from miconia naturalized in North Queensland, Australia (Fletcher and Westcott 2013). In this spatial model, 99% of recruitment was within 609 m with rare stochastic events (i.e., 1%) extending out to 1644 m. Based on these biological features, one autogamous, mature plant can impact up to 850 ha (i.e., 2100 acres) of forested watershed with hundreds to thousands of dispersed progeny germinating asynchronously over several decades (Fig. 1).

Figure 1. The dispersal kernel displays as a raster layer creating an 850-ha area calculation with corresponding probability density function (color shades).

Effective management is achieved when target mortality outpaces biological recruitment. Cacho et al. (2007) coined the term ‘‘mortality factor’’ described by the simple equation: m=Pd x Pk, where the probabilities of detection (Pd ) and kill (Pk)are equal determinants of the “mortality” product. Our current Pk is 0.98 for all HBT treatments. With this effective and reliable treatment technique, management outcomes largely depend on detection (Leary et al. 2013; Lodge et al. 2006). Koopman (1946) introduced the mathematical framework for estimating the probability of detection: Pd=1-e-c, where the probability of detection asymptotically approaches 1.0 with increasing coverage (Fig. 2). In operations, imperfect detection can be compensated by frequent interventions compounding coverage levels over time, but with obvious diminishing returns (Leary et al. 2014).

Figure 2. Probability of detection (blue) and the inverse for the equally important confirmation of no targets (orange). Note gray dash connotation of a theoretically “perfect” sensor, where coverage is equal to detection and confirmation.

The variable costs for HBT operations (e.g., flight time and projectiles) are driven by target density (Leary et al 2013, Leary et al. 2014). With that knowledge, we estimate the cost to manage the area (i.e., 850 ha) impacted by the dispersal of new progeny created by a mature plant. A new mature miconia with two panicles may produce ~300-400 progeny. With a single, incipient target being such a high risk, intensive efforts should be matched to comprehensively search the entire impact area over the several decades with a level probability of detection (and equal confirmation of no targets) of all progeny recruits. For instance, with 320 propagules dispersed, Pd would need to exceed 0.9968 with coverage at 5.77 s per 100 m2 pixel totaling ~136 hours of effort over the entire impact area over four decades (Fig. 3A). Any level of coverage less than that (including 99%) would be prone to missing a target that ultimately reaches maturity and newly replenishes the seed bank (Fig. 3B). Furthermore, an overwhelming majority of search effort would actually be dedicated to the confirmation of no targets, where, for instance 87% of effort is invested in looking for 1% of the targets dispersed out to the perimeter.

Figure 3. (A) Search effort (EFT; hours) over a 43-year period to match the level of coverage with the probability of detection from a random search effort. (B) is the reproduction of 2nd generation progeny by undetected targets of the 1st generation shown as Base 10 log scale.

Based on this model, we estimate accrual of future management costs ranging from $169,000-337,000 for every mature target detected, with the increase from the base cost dependent on increasing propagule loads and the static cost to treat each those individuals detected.

- James Leary, Kimberly Burnett and Christopher Wada


 

References

Cacho, O.J., Hester, S. and Spring, D., 2007. Applying search theory to determine the feasibility of eradicating an invasive population in natural environments. Australian Journal of Agricultural and Resource Economics, 51(4), pp.425-443. 


Fletcher C. S. and Westcott D. A.. 2013. Dispersal and the design of effective management strategies for plant invasions: matching scales for success. Ecological Applications 23:1881–1892. 


Koopman, B.O. (1946). Search and Screening. Operations Evaluations Group Report no. 56, Center for Naval Analyses, Alexandria, VA. 


Leary, J.J., Gooding, J., Chapman, J., Radford, A., Mahnken, B. and Cox, L.J., 2013. Calibration of an Herbicide Ballistic Technology (HBT) helicopter platform targeting Miconia calvescens in Hawaii. Invasive Plant Science and Management, 6(2), pp.292-303. 


Leary, J., Mahnken, B.V., Cox, L.J., Radford, A., Yanagida, J., Penniman, T., Duffy, D.C. and Gooding, J., 2014. Reducing nascent miconia (Miconia calvescens) patches with an accelerated intervention strategy utilizing herbicide ballistic technology.

Lodge, D.M., Williams, S., MacIsaac, H.J., Hayes, K.R., Leung, B., Reichard, S., Mack, R.N., Moyle, P.B., Smith, M., Andow, D.A. and Carlton, J.T., 2006. Biological invasions: recommendations for US policy and management. Ecological Applications, 16(6), pp.2035- 2054. 



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