Research

Ecosystem services and landscape dynamics assessment
I am engaged in research that explores linkages between ecosystem services and drivers of broad-scale landscape change, to provide tools and information for managing and conserving the capacities of ecosystems to provide benefits to people. This work is a collaboration between the US Forest Service’s Eastern Forest Environmental Threat Assessment Center (EFETAC) and the Appalachian Landscape Conservation Cooperative. The Appalachian region encompasses a rich diversity of forests, streams, and other natural resources. Millions of people benefit from ecosystem services provided here, as diverse as clean water, forest products, outdoor recreation and tourism, fish and wildlife conservation, and the recycling and storage of carbon and nutrients. The region is also the scene of rapid environmental change, which may compromise the sustainability of ecosystem services. Major drivers include changes in land use driven by urbanization and energy development; climate change; and large-scale disruptions associated with wildland fire, forest pathogens, invasive species, and other factors acting across large landscapes.

The first phase of this effort resulted in an online synthesis of findings from an exhaustive collection of broad-scale ecosystem service assessments and related geospatial data products that have relevance for the Appalachian region. Building on this inventory and synthesis, we are developing geospatial tools for assessing the sustainability of ecosystem services such as forest carbon storage and the provisioning of wildlife habitat and clean water, given their vulnerabilities to a variety of large-scale stressors. This project has made significant contributions to the development of the Landscape Dynamics Assessment Tool (LanDAT), and I am using LanDAT to develop spatial assessments of ecosystem services and stressors for the Appalachian region.

 

LanDAT is a set of computer-intensive methods, and resulting spatial data products, that monitors land surface phenology across the conterminous United States and produces annually updated measures of landscape organization and dynamics. The goal is to provide quantitative ecological characterizations of landscapes and landscape change that allow the assessment of landscape resilience and adaptive capacity. For more information, visit the LanDAT website or project description below.

 

 

Related articles
Brooks, B.G.J., Lee, D.C., Pomara, L.Y., Hargrove, W.W. & Desai, A.R. 2017. Quantifying seasonal patterns in disparate environmental variables using the PolarMetrics R package. 2017 IEEE International Conference on Data Mining Workshops (ICDMW), 296-302. DOI: 10.1109/ICDMW.2017.45. PDF

Related online content
LanDAT website
LanDAT project description (EFETAC)
Ecosystem Services Conservation Atlas (EFETAC / Appalachian LCC)
Ecosystem Benefits and Risks website (Appalachian LCC)

Landscape community ecology
I am engaged in research to understand how bird and butterfly communities respond to ongoing ecological restoration efforts in riparian habitats in the floodplain of the Rio Grande (also known as the Rio Bravo in Mexico), in Big Bend National Park on the US/Mexico border. This work is a collaboration with colleagues at Cal State LA in the Wood Lab, including Dr. Eric Wood and graduate students Heather Mackie and Julie Coffee, and the Division of Science and Resource Management at Big Bend National Park.

Natvie and non-native vegetation along the Rio Grande/Bravo in Mexico and Texas

Reakirt’s Blue butterfly nectaring on Tamarisk (salt cedar), a non-native invasive woody shrub/tree in North American desert riparian systems.

The Rio Grande riparian system is one of the most significant of its kind in the US southwest and northern Mexico, providing habitat for a wide array of plant, fish, and wildlife species. The river and its floodplain have changed dramatically over the past century due to water diversion for agricultural irrigation, damming, urban expansion, floodplain agriculture, and other impacts. These changes have facilitated the spread of invasive plant species, which can further alter river hydrology and reduce habitat quality for riparian associated wildlife species. In response, Big Bend National Park and its sister protected areas in northern Mexico are undertaking a major restoration initiative, using prescribed fire and manual treatments to remove invasive plant species, principally giant cane (Arundo donax), along 118 miles of shared river floodplain. A recent New York Times story highlighted this difficult work in a visually stunning way. With support from the National Park Service,  we are assessing the effectiveness of the restoration efforts by monitoring the status of the floodplain bird and butterfly communities in relation to vegetation treatments. We hope to establish a baseline understanding of how community structure and diversity vary across the landscape with variations in habitat, and examine how these community characteristics are affected when the treatments alter the vegetation. A species of particular concern is the Yellow-billed Cuckoo, whose western population was recently listed as threatened under the US Endangered Species Act. We are using occupancy modeling to examine habitat relationships across the landscape and over time for the Yellow-billed Cuckoo and other select species, with the hope that findings can help conservation partners manage habitat for species of conservation concern.

Related articles
Mackie, H., J. Coffey, E. M. Wood, and L. Y. Pomara. 2017. Bird and butterfly community response to large-scale invasive plant removal and native plant restoration in desert riparian habitat along the Rio Grande/Bravo, Big Bend National Park, Texas. 2016 annual report to the National Park Service, 19pp.

Climate change vulnerability assessment
My research as a postdoctoral scientist in the Zuckerberg Climate Change Ecology Lab in the Department of Forest and Wildlife Ecology at the University of Wisconsin-Madison was focused on understanding how climate change affects wild animal populations, and I remain engaged in this ongoing project. Climate change vulnerability assessment represents an effort to estimate demographic sensitivities to variable climatic factors, estimate the exposure of species to changes in those factors in different parts of their range over time, and infer population dynamic and distributional consequences of those dynamics.

Eastern Massasauga. Photo by Mike Redmer, USFWS

Eastern Massasauga Rattlesnake, Sistrurus catenatus. Photo by Mike Redmer, USFWS

To do this, we have developed spatially explicit, full life-cycle demographic models for Eastern Massasauga Rattlesnake (Sistrurus catenatus) and for Ruffed Grouse (Bonasa umbellus), in collaboration with the Upper Midwest and Great Lakes Landscape Conservation Cooperative and the Wisconsin Department of Natural Resources. Our models combine species demographic and distributional information with climate and land use/land cover models to first investigate how populations have been influenced over time by past environmental change, then use this information to project expected demographic and distributional change under future climate and land use change scenarios. Our ultimate goal is to develop recommendations for what kinds of conservation strategies will be most effective in coping with the particular kinds of vulnerabilities that we identify for different species and different places, and to communicate findings to natural resource managers. Findings from our study of Eastern Massasauga Rattlesnake have been used in the USFWS species status assessment to help evaluate this species’ candidacy for listing (threatened) under the Endangered Species Act.

Related articles
Zuckerberg, B. and L. Y. Pomara. In press. Modern climate change and birds. In Morrison, M. L., A. D. Rodewald, G. Voelker, M. R. Colón, and J. F. Prather, editors. 2018. Ornithology: Foundation, Critique, and application. Johns Hopkins University Press, Baltimore, Maryland.

Pomara, L. Y. and B. Zuckerberg. 2017. Climate variability drives population cycling and synchrony. Diversity & Distributions 23: 421-434. PDF

McCauley, L. A., C. A. Ribic, L. Y. Pomara, and B. Zuckerberg. 2017. The future demographic niche of a declining grassland bird fails to shift poleward in response to climate change. Landscape Ecology 32: 807-821. PDF

Pomara, L. Y., O. LeDee, K. J. Martin, and B. Zuckerberg. 2014. Demographic consequences of climate change and land cover help explain a history of extirpations and range contraction in a declining snake species. Global Change Biology 20, 2087-2099.  PDF

Pomara, L. Y., B. Zuckerberg, K. J. Martin, and O. LeDee. 2014. A climate change vulnerability assessment for the Eastern Massasauga Rattlesnake (Sistrurus catenatus), an endemic of the Upper Midwest and Great Lakes region. Upper Midwest and Great Lakes Landscape Conservation Cooperative. Project link.

Ecological biogeography
In my doctoral research, I investigated heterogeneity in avian species composition and turnover in western Amazonian forests, examining associations between this heterogeneity and local environmental variation as well as a large-scale dispersal barrier. I approached community assembly in terms of multiple processes operating at multiple scales, providing information for refining bioregional delineations.

Tangara schrankii, Green-and-gold Tanager

Tangara schrankii, Green-and-gold Tanager– a denizen of western Amazonian forests growing on nutrient-rich soils

I found unique evidence for predictable vertebrate species turnover among landscapes with different soil properties and consequently different plant species compositions, linking biogeographic pattern to the region’s recent geological history. I also found taxonomically pervasive species turnover and relative abundance variation in birds across the Amazon River, whereas this well-known biogeographic boundary explained almost no plant species turnover. Additional elements of avian compositional change among study sites, as well as reduced diversity, were associated with anthropogenic forest fragmentation in the landscapes surrounding the study sites.

Understory plant in the family Melastomataceae, a group that has proven effective as an indicator of Amazoninan forest types

I hope to (one day!) extend the research agenda developed during my doctoral studies by employing ecological and phylogenetic characterizations of beta-diversity, as well as species distribution modeling, to discover ecological drivers of geographic patterns in terrestrial vertebrate diversity.

In the Amazonian case, this critically involves river floodplain boundaries and the large-scale spatial patterning in soil types induced by long-term geomorphologic process. One applied goal is to detail the taxonomic and ecological specificities of spatial partitioning in species assemblages, since models of these spatial patterns can be useful for conservation planning. Another goal is to understand the role of niche differentiation in generating and maintaining these patterns. I am particularly interested in the role that social environments may play in this process, including factors such as competition within and among species at boundaries such as rivers, and along geomorphologic gradients.

Related articles
Pomara, L. Y., K. Ruokolainen, and K. R. Young. 2014. Avian species composition across the Amazon River: the roles of dispersal limitation and environmental heterogeneity. Journal of Biogeography 41: 784-796.  PDF

Pomara, L. Y., K. Ruokolainen, H. Tuomisto, and K. R. Young. 2012. Avian composition co-varies with floristic composition and soil nutrient concentration in Amazonian upland forests. Biotropica 44: 545-553.  PDF

Socolar, J. B., J. D. Alván, P. Saboya del Castillo, L. Y. Pomara, B. J. O’Shea, S. Cubas Poclin, D. Stotz, F. Schmitt, D. Graham, B. H. Carnes, & E. Ruelas Inzunza. In press. Noteworthy bird records from northeastern Peru reveal connectivity and isolation in the western Amazonian avifauna. Wilson Journal of Ornithology.

Behavioral ecology:  mixed-species flocking
My master’s thesis examined the influence of habitat variation on mixed-species flocking and foraging behavior of passerine birds, across an agricultural and forest reserve landscape in the highlands of western Panama. This work was part of a Smithsonian Migratory Bird Center research program, investigating the role that traditionally managed shade coffee farms play in providing habitat for resident birds as well as Nearctic migrants.

Traditionally managed shade coffee field at Finca Hartmann, in western Panama

Traditionally managed shade coffee field at Finca Hartmann, in western Panama

I compared the flocking behavior of five songbird species (three year-round residents and two Nearctic migrants) between shade coffee and mature forest habitats, asking what might account for any important differences. The amount of foraging time spent in mixed-species flocks was lower in coffee fields than in forest for all species, and was directly proportional to home range size, within and among species. Foraging strategies and apparent success differed very little between habitats and between flocking and solitary individuals. Slate-throated Redstart (Myioborus miniatus) was a unique exception in that home range sizes in coffee fields were equal to or larger than those in forests, but flocking propensities were nonetheless much lower in coffee fields. This species used markedly different foraging styles in the two habitats, and also switched foraging styles between solitary and flocking situations, apparently adapting to novel habitat conditions with flexible flocking and foraging strategies. I maintain an active interest in mixed-species flocking research, and hope to do more work on the subject in the future.

Vireo flavifrons, Yellow-throated Vireo and Lepidocolaptes affinis, Spot-crowned Woodcreeper

Related articles
Pomara, L.Y., R. J. Cooper and L. J. Petit. 2007. Modeling the flocking propensity of passerine birds in two Neotropical habitats. Oecologia 153: 121-133. PDF

Pomara, L.Y., R. J. Cooper and L. J. Petit. 2003. Mixed-species flocking and foraging behavior of four Neotropical warblers in Panamanian shade coffee fields and forests. The Auk, 120: 1000-1012. PDF

 

Species distribution modeling
The spatially explicit modeling of species’ distributions, habitat suitabilities, and demographic characteristics has proven useful for understanding processes as diverse as habitat selection, range dynamics altered by climate change, and even speciation. My work in the Zuckerberg Lab at the University of Wisconsin-Madison (see Climate Change Vulnerability Assessment, above) incorporated demographic processes such as productivity, survival, and dispersal into spatial models in such a way that modeled distributional dynamics emerge from population ecological dynamics.

Aerial view of urban / protected area landscape transition in California coastal region occupied by Spotted Owls

Aerial view of urban / protected area landscape transition in California coastal region occupied by Spotted Owls

Spotted Owl (Strix occidentalis) nesting habitat niche model for three ecoregions in coastal California, from Stralberg et al. (2009).

Spotted Owl (Strix occidentalis) nesting habitat niche model for three ecoregions in coastal California, from Stralberg et al. (2009).

At PRBO Conservation Science I also collaborated on a landscape-scale study of nest site habitat suitability for Spotted Owl (Strix occidentalis). In that project, we developed spatially explicit habitat suitability models specifically for nest sites, near an urban/protected area interface in coastal California, and tested extrapolations of the models to neighboring ecoregions. Results helped to understand habitat distributions in an area where suburban development affects this threatened species. Nest site selection also appeared to vary considerably between wetter coastal sites and drier inland sites (i.e., to be non-stationary), suggesting that modeling efforts should be locally tailored.

Related articles
Pomara, L. Y. and B. Zuckerberg. 2017. Climate variability drives population cycling and synchrony. Diversity & Distributions 23: 421-434. PDF

McCauley, L. A., C. A. Ribic, L. Y. Pomara, and B. Zuckerberg. 2017. The future demographic niche of a declining grassland bird fails to shift poleward in response to climate change. Landscape Ecology 32: 807-821. PDF

Pomara, L. Y., O. LeDee, K. J. Martin, and B. Zuckerberg. 2014. Demographic consequences of climate change and land cover help explain a history of extirpations and range contraction in a declining snake species. Global Change Biology 20, 2087-2099.  PDF

Stralberg, D., K. E. Fehring, L. Y. Pomara, N. Nur, D. B. Adams, D. Hatch, G. R. Geupel, and S. Allen. 2009. Modeling nest-site occurrence for the Northern Spotted Owl at its southern range limit in central California. Landscape and Urban Planning 90:76-85. PDF

Conservation planning
I have engaged in conservation planning research in both academic and non-profit professional settings. At PRBO Conservation Science I collaborated on a state-wide riparian habitat management strategy for the conservation of wildlife diversity in California, contributing to landscape-ecological components of the plan as well as target-setting strategies for songbird habitat restoration. In Texas, I collaborated on a systematic conservation planning project to prioritize landscapes for non-profit conservation partnerships with private landowners, within six major Texas watersheds. We used complementarity-based analyses to integrate biological diversity criteria with economic and cultural considerations such as water quality, scenic value, and development pressure. In addition, my more recent work at the US Forest Service in collaboration with the Appalachian Landscape Conservation Cooperative (see above) has made contributions to several online resources for understanding the large-scale spatial distributions of ecosystem services and environmental stressors. Some of these products have been incorporated into the Appalachian LCC’s spatial conservation planning analyses.

The Landscape Dynamics Assessment Tool (described above) has been applied to modeling carbon stock dynamics at landscape scales in the eastern US. Quantifying rates of change in terrestrial carbon stocks can help planners prioritize both places to implement conservation efforts and management strategies in those places.

Related articles
Ogren, J., L. Y. Pomara, and M. Steinbach. 2012. Land for water: a conservation initiative. A strategic framework for landscape change. Texas Land Conservancy, Austin. 37pp.

RHJV (Riparian Habitat Joint Venture—Group authorship). 2004. Version 2.0. The riparian bird conservation plan: a strategy for reversing the decline of riparian associated birds in California. California Partners in Flight. http://www.prbo.org/calpif/pdfs/riparian_v-2.pdf.

Related online content
LanDAT website

Ecosystem Services Conservation Atlas (EFETAC / Appalachian LCC)

 

 

Natural history and taxonomy
I have a long-standing interest in the natural history of birds, and I have made an effort to contribute to basic monitoring and description of aspects of bird life. These projects are closely linked to my interest in conservation, biogeography, and landscape ecology. For example, I have an ongoing project monitoring habitat use by the Black-capped Vireo population in Big Bend National Park, Texas. Understanding how this population occupies and uses habitats within the park can aid conservation efforts by improving ecosystem management practices. I am also involved in avian taxonomic description work in Peru. Taxa (usually species) constitute basic units of investigation in biogeography, and our understanding of biogeographic pattern and process depends heavily on how taxonomic limits are understood and described.

Big Bend National Park, Texas

Related articles
Zuckerberg, B. and L. Y. Pomara. In press. Modern climate change and birds. In Morrison, M. L., A. D. Rodewald, G. Voelker, M. R. Colón, and J. F. Prather, editors. 2018. Ornithology: Foundation, Critique, and application. Johns Hopkins University Press, Baltimore, Maryland.

Socolar, J. B., J. D. Alván, P. Saboya del Castillo, L. Y. Pomara, B. J. O’Shea, S. Cubas Poclin, D. Stotz, F. Schmitt, D. Graham, B. H. Carnes, & E. Ruelas Inzunza. In press. Noteworthy bird records from northeastern Peru reveal connectivity and isolation in the western Amazonian avifauna. Wilson Journal of Ornithology.

Jones, C. D., J. R. Troy, and L. Y. Pomara. 2007. Similarities between Campephilus woodpecker double raps and mechanical sounds produced by duck flocks. Wilson Journal of Ornithology 119:259-262.  PDF

Pomara, L. Y. (Annual reports, 2009-2017) Black-capped Vireo Habitat Occupancy Survey. Endangered species report to the National Park Service, Big Bend National Park, Texas.

Round, P. D., G. A. Gale, M. R. Marshall, and L. Y. Pomara. 2002. An expedition to the summit of Khao Soi Dao Tai, Southeast Thailand. Oriental Bird Club Bulletin 35: 49-53.

Roberts, D. L., L. Y. Pomara, and A. Hartmann. 1999. First nest records for the Spotted Wood-Quail from premontane western Panama. Newsletter of the Partridge, Quail and Francolin Specialist Group 13/14: 2-3.

Christian, D., A. Williams, D. L. Roberts, and L. Y. Pomara. 2000. Checklist of the birds of Finca Hartmann, Chiriqui, Panama. http://www.fincahartmann.com/pgs/birds_list.htm

Wilson, H. M., R. Kaler, L. Y. Pomara, R. Hartmann, Sr. and R. Hartmann, Jr. 2000. Checklist of the mammals of Finca Hartmann, Chiriqui, Panama. http://www.fincahartmann.com/pgs/mammals_list.htm