Publication Type: Conference Paper/Unpublished Manuscript
Review Method: Peer Reviewed
Abstract: Population migration can have dramatic health effects (e.g., the Spanish introduction of smallpox to New World inhabitants). Health effects can also be subtle, especially given the long latency of diseases such as cancers. Separately, places in the U.S. may be ranked as persistently healthy and unhealthy places, based on a variety of health measures. As such, we investigate how socioeconomic factors and population migration relate to the relative health of these counties. Assessment of the stable population is necessary to correctly determine the “at-risk” population for either the incidence or prevalence of morbidity/mortality within a population. Further, understanding population migration flows can reveal the role that place versus the population or community play in morbidity and mortality outcomes. Using mortality as a health outcome and socioeconomic factors as controls, we test the importance of county-level population stability and in-migration. Population in-migration is negatively associated with mortality rates except in already unhealthy places, while population stability (non-movers) is positively associated with mortality rates no matter how counties are grouped. This finding supports previous research from other countries, indicating that healthy people move from unhealthy places while unhealthy people remain in unhealthy places. This is also supportive of parallel research in the migration patterns of the poor, in which migration is found to maintain and reinforce spatial concentrations of poverty. We conclude that migration and stability reinforce the health status of county populations and plan to examine in more detail the migration patterns among healthy and unhealthy places in future research.

Publication Type: Conference Paper/Unpublished Manuscript
Review Method: Peer Reviewed
Abstract: This paper presents a test of elements of Power Transition Theory (PTT) through an examination of types of demographic transitions against civil war. It divides population transitions into nine types and, from PTT logic, derives testable hypotheses. It also tests elements of PTT's rival, Balance of Power Theory (BPT). Although the logic of PTT seems appropriate to testing at the substate level, the results are mixed. Most states plagued by ethnic civil wars have stable populations (i.e. no transitions), yet three types of transitions stand out. Even here, however, PTT predicts violence in only one of these three types of transitions. BPT fares a bit better.

Publication Type: Conference Paper/Unpublished Manuscript
Review Method: Peer Reviewed
Abstract: In 1998, a ballot initiative within the Sierra Club (SC) on whether or not to consider migration as a part of its population policy tore the environmental movement apart and shook it down to its foundation, leaving a wound that still remains to this day. A group that splintered from the SC, Sierrans for US Population Stabilization, began the controversial process when SC’s Board of Directors had revised the population policy to not include migration as a consideration of sustaining US population growth.
What is most interesting is how the environmental movement found itself inadvertently at the center of a charged public debate. On one side are leftist-progressive activists who represent environmental justice, feminist, and immigrant/human rights organizations stated how it is xenophobic to blame immigrants for U.S. population problems and environmental degradation and instead pointed out that attention needed to be centered on human rights, not population control. On the other side, there are rightist-restrictionist activists who represent immigration control and population groups who believe immigration policy needs to be changed, in terms of reducing the numbers of immigrants, as current numbers are viewed as too large for sustaining U.S. population growth, and that not paying attention to immigration’s contribution to population is “intellectually dishonest.”
Being unable to find a middle ground and escape the stigma of racism, most environmental organizations have taken on a “neutral position” on immigration, where they do not have a position or state that immigration needs to be included, but not how. However, this is a complex issue that will not disappear in the 21st century, as we continue to deliberate over the effects of transnational politics and our globalized economy, and environmental and population policies continue to hang in the balance.
This study will explore the emergence and flux of population and immigration issues through the context of the environmental movement, content analysis of how the immigration debate and population policies have been covered in the media, and interviews with a wide range of population and environmental activists from various perspectives on the continuum. The goal of this research is to bring an understanding and context to these issues, build bridges to understanding the differing perspectives and perhaps find a middle ground to talk about them.

Publication Type: Abstract
Abstract: Among the projected outcomes of human-induced climate change is the extinction of many species, however predicting the specific effects of climate change is often confounded by associated and interacting processes. The black abalone, Haliotis cracherodii, along with all species of California abalone, has experienced significant declines in abundance over portions of its range over the past few decades. A combination of stressors has contributed to these declines including overexploitation, habitat modification, and withering syndrome (WS), a chronic wasting disease first observed along the northern Channel Islands, California following the 1982-1983 El Nino. This disease, caused by a rickettsia-like prokaryote, has been found in wild populations of most abalone species south of Santa Mateo County and is augmented by food supply and thermal stress associated with anomalous sea surface temperature. The northward spread of WS has been well documented and under even modest scenarios of climate change it must be anticipated that this disease will impact individuals across this species’ entire range. The dynamics of declining populations were investigated at 10 permanent intertidal study sites in Channel Islands National Park to test hypotheses of deteriorating population dynamics as extinction nears. Simulations of processes driving population declines highlight the causal mechanisms of local extinctions and provide an outlook for the fate of remaining populations.

Publication Type: Abstract
Abstract: We assessed the pre-enforcement status of queen conch populations in the Sapodilla Cayes Marine Reserve (SCMR) in southern Belize in spring and summer 2006 and 2007, collecting data on density and age structure of aggregations inside and outside the reserve in shallow-water (<3m; N=10) and deep-water (>15 m; N=2). We also tagged conch to study dispersal/migration patterns. Aggregation densities were among the highest reported. Shallow-water aggregations consisted mainly of juveniles and were found in seagrass meadows. Deep-water aggregations were found in sand and sand/seagrass habitats and contained only adults. Spawning was observed in these aggregations and, thus, may act as spawning refugia. Preliminary analysis of tagging data suggests that juveniles migrate seasonally between shallow (spring-summer) and deep (fall-winter) sites while adult conch from deep-water aggregations are sedentary. To assess genetic population structure and connectivity among populations, DNA was sampled from three locations in Belize (SCMR, Port Honduras Marine Reserve, Turneffe Atoll) and one location in the Turks and Caicos Islands. Estimates of polymorphism at the mitochondrial CO1 locus are high and average pairwise divergence among pairs of the Belize populations and the TCI population ranged from 0.00456 to 0.00592. Fst values among pairs of Belize populations were low. Thus, currently, with limited data, our sampling has not found spatial or temporal population structure within Belize.