Publication Type: Abstract
Abstract: One potential consequence of the widespread introduction of nonindigenous species is the loss of regional biotic distinctiveness, leading to taxonomic homogenization of biotas among localities. Similarity indices such as Jaccard’s Index are often used to assess changes in compositional similarity resulting from species introductions and these indices are useful metrics of taxonomic homogenization in invaded regions. However, changes in species richness alone can result in significant changes in similarity for probabilistic reasons, leading to potential misinterpretations of the role of introduced species in biotic homogenization. A null model approach can be used to account for this probabilistic effect of species richness on similarity measures, allowing a more accurate assessment of the effects of nonindigenous species on biotic similarity and biodiversity. Our null model results show that similarity indices can suggest biotic homogenization when in fact none has occurred (“pseudohomogenization”), or they can suggest an absence of homogenization when it actually has occurred (“cryptic homogenization”). Null expectations can also be generated to predict situations where misinterpretations are most likely. We suggest that the more widespread application of a null model approach to studies of biotic homogenization will improve our understanding of how species introductions affect compositional similarity and regional diversity.

Publication Type: Conference Paper/Unpublished Manuscript
Review Method: Peer Reviewed
Abstract: The extent to which immigrants develop primary relations with members of the majority group has traditionally formed the keystone of classical assimilation theory. However, lack of data has led most empirical examination of this idea to rely on the study of patterns of spatial assimilation focusing on the foreign-born and not the later generations of immigrant groups. This paper compares the level of racial and ethnic homogeneity in strong ties between the foreign-born and native-born of two immigrant groups in Los Angeles County. It finds that the native-born of these groups have a significantly higher proportion of interethnic and interracial ties, but that these differences are largely confined to the native-born living outside ethnic enclaves and in wealthier areas. It further finds that for those of Mexican origin, the foreign-born have a higher proportion of strong ties with neighbors than with people living farther away. The paper discusses the implications for new theories of assimilation or incorporation.

Publication Type: Conference Paper/Unpublished Manuscript
Abstract: Neighborhood and community studies often assume neighborhood boundaries or use preexisting census tract geography and census data as the best approximation of neighborhood or community topography. As a result, much sociological research reflects the belief that neighborhood boundaries are best delineated through an assumption of homogeneity as measured through the census and located within a specific geographic space. Unfortunately, researchers fail to conceptualize homogeneous population groupings outside of U.S. Census data. I argue that homogeneity is thus the primary characteristic used in defining neighborhood identity and physical boundaries in most current urban sociological research. Using Cluster analysis I offer an alternative measure of homogeneity based on residents’ consumption preferences. Results suggest that there are no less than twelve consumption communities and that consumption is in fact a strong measure of homogeneity.

Publication Type: Conference Paper/Unpublished Manuscript
Abstract: Political communication scholars have put forward contrasting theories and produced contradictory evidence in attempts to explain the impact of heterogeneity of political discussion on active citizenship. However, most of these studies examined the effects of heterogeneous discussion independently of homogenous discussion. This is overly simplistic, of course, given that most citizens are likely to be mobilized through discussion with both likeminded and non-likeminded discussion partners. This study examines the opposing claims on the civic consequences of heterogeneous political discussion empirically and directly compares the influence of heterogeneous and homogeneous political discussion on indicators of active citizenship. Overall, two general findings emerged. First, heterogeneous political discussion does encourage democratic citizenship and, second, heterogeneous political discussion and homogeneous political discussion have different effects on indicators of active citizenship.

Publication Type: Conference Paper/Unpublished Manuscript
Abstract: This paper examines homogeneity and heterogeneity in preferences for public policy, across income and education levels and party identification, and across policy domains in the US, UK, and Canada. Do preferences differ across segments of the public at particular points in time? What about over time – do we observe a uniform swing across different groups (parallel publics) or does the flow of opinion differ across party, income, and education? Our data on public preferences for government spending show cross-sectional heterogeneity across certain sub-aggregates in some domains, but overall very high levels of over-time homogeneity in trends across groups.