Urban ecosystem Services in Latin America: mismatch between global concepts and regional realities?

Urban Ecosystems - Latin America and the Caribbean (LAC) is one of the most urbanized and biologically diverse regions in the world but is often characterized by weak environmental governance and...     

Model-based clustering with sparse covariance matrices

Statistics and Computing - Finite Gaussian mixture models are widely used for model-based clustering of continuous data. Nevertheless, since the number of model parameters scales quadratically with...     

Demography of a ground nesting bird in an urban system: are populations self-sustaining?

Urbanization poses threats to earth’s biota, and retention of remnant native habitat in protected areas within expanding urban boundaries may help alleviate threats to wildlife. However, it is unclear for nearly all nonsynanthropic (i.e., not benefiting from an association with humans) species whether vital rates in urban habitats can sustain populations or if populations persist only through immigration from outside the urban boundary. We conducted a three-year study of spotted towhees (Aves: Pipilo maculatus) breeding in four undeveloped parks in Portland, OR, USA, to measure park-specific seasonal reproductive output (F) and annual adult survival (S_A). We developed a stochastic model that combined F and S_A with an estimate of first-year survival to measure population growth rate (λ) in all parks assumed to be closed to immigration. F differed among parks but S_A did not. Relatively high F was possible because many pairs raised >1 brood/season. When combined with empirical estimates of survival through the 30-day period of post-fledging parental care (S_D = 0.645), only 2 of 4 parks were self-sustaining (i.e., λ > 1.0). However, S_D reflected substantial loss of fledglings to domestic cats (Felis catus). Assuming no loss to cats and either partial compensatory or additive mortality of fledglings substantially improved prospects of population persistence for declining (sink) populations. Moreover, allowing low levels of immigration to sinks reversed population declines in most parks even when vital rates were insufficient to maintain populations. Our results suggest that nonsynanthropic bird species can persist in urban landscapes, but also that offspring mortality in the post-fledging period may be a critical determinant of population viability.     

Dual conditionality in welfare and housing for lone parents in Ireland: Change and continuity?

This article focuses on multiple conditionalities in benefits and housing from the perspective of lone parents in Ireland. The Irish case echoes historical experiences elsewhere and is offered not as an exceptional or extreme case but as an in-depth single case study and a lens for comparison. Although contemporary forms and combinations of conditionalities are new to Ireland, the experience of multiple conditionalities in benefits and housing is not new. Hence, a historical perspective is used to examine contemporary multiple conditionalities in benefits and housing. In the past, conditional regimes for lone parents were justified in terms of moral reformation for first time mothers and avoiding moral contagion of mothers with subsequent pregnancies. In contemporary times, in the case of employment, lone parents are problematised as working part-time and “nesting” on in-work-benefits, and in the case of homelessness, lone parents who prioritise the security of tenure embedded in social housing are accused of “gaming” the system. While acknowledging ambiguities, the paper finds the overlap of welfare and housing discourses contribute, intentionally or unintentionally, to epistemological foundations or understandings of lone parents, shifting public perceptions, and framing them as “problems” to be solved. They simultaneously temper lone parents' expectations. Increased precarity and disempowerment is associated with dual conditionality, and ontological uncertainty is multiplied when experienced cumulatively across employment, social protection, and housing regimes in a context of generally poor public services and labour market precarity and in the historical context of stigmatisation. Nonetheless, lone parents demonstrate considerable agency.     

Urbanization impacts the taxonomic and functional structure of aquatic macroinvertebrate communities in a small Neotropical city

Due to habitat fragmentation, resource disruption and pollution, urbanization is one of the most destructive forms of anthropization affecting ecosystems worldwide. Generally, human-mediated perturbations dramatically alter species diversity in urban sites compared to the surroundings, thus influencing the functioning of the entire ecosystem. We investigated the taxonomic and functional diversity patterns of the aquatic macroinvertebrate communities in tank bromeliads by comparing those found in a small Neotropical city with those from an adjacent rural site. Changes in the quality of detrital inputs in relation to lower tree diversity and the presence of synanthropic species are likely important driving forces behind the observed structural changes in the urban site. Leaf-litter processors (i.e., shredders, scrapers) were positively affected in the urban site, while filter-feeders that process smaller particles produced by the activity of the shredders were negatively affected. Because we cannot ascertain whether the decline in filter-feeders is related to food web-mediated effects or to competitive exclusion (Aedes aegypti mosquitoes were present in urban bromeliads only), further studies are necessary to account for the effects of intra-guild competition or inter-guild facilitation.     

Women’s experiences of,and attitudes to,maternity education across the perinatal period in Victoria,Australia: A mixed-methods approach

Background

While the provision of maternity education across the perinatal period can increase the confidence and self-efficacy in childbearing women, there is still thought to be a lack of effective educational resources for parenthood. This study, conducted in Victoria, Australia, investigated women’s experiences of, and attitudes to education communicated in maternity service provision.

Mixture of latent trait analyzers for model-based clustering of categorical data

Model-based clustering methods for continuous data are well established and commonly used in a wide range of applications. However, model-based clustering methods for categorical data are less standard. Latent class analysis is a commonly used method for model-based clustering of binary data and/or categorical data, but due to an assumed local independence structure there may not be a correspondence between the estimated latent classes and groups in the population of interest. The mixture of latent trait analyzers model extends latent class analysis by assuming a model for the categorical response variables that depends on both a categorical latent class and a continuous latent trait variable; the discrete latent class accommodates group structure and the continuous latent trait accommodates dependence within these groups. Fitting the mixture of latent trait analyzers model is potentially difficult because the likelihood function involves an integral that cannot be evaluated analytically. We develop a variational approach for fitting the mixture of latent trait models and this provides an efficient model fitting strategy. The mixture of latent trait analyzers model is demonstrated on the analysis of data from the National Long Term Care Survey (NLTCS) and voting in the U.S. Congress. The model is shown to yield intuitive clustering results and it gives a much better fit than either latent class analysis or latent trait analysis alone.     

Charting the Emergence of National Identity in Children in Wales

This multimodal study, set in Wales, demonstrates that children aged nine and ten can clearly define and rationalise their own national identity. It contributes to age related discussions on how children categorise themselves in terms of national identity and the rationale for their choices. The children in the study used single and multiple definitions of national identity and illustrate the increasing plural nature of 21st century Wales. Family, birthplace and residency were identified as factors in shaping their national identity, more so than language, despite the current bilingual policy drive in Wales.