A Geography of Cohabitation in the Americas, 1970-2010

In this chapter, we trace the geography of unmarried cohabitation in the Americas on an unprecedented geographical scale in family demography. We present the percentage of partnered women aged 25-29 in cohabitation across more than 19,000 local units of 39 countries, from Canada to Argentina, at two points in time, 2000 and 2010. The local geography is supplemented by a regional geography of cohabitation that covers five decades of data from 1960 to 2010. Our data derive primarily from the rich collection of census microdata amassed by the Centro Latinoamericano y Caribeño de Demografía (CELADE) of the United Nations and from the IPUMS-international collection of harmonized census microdata samples (Minnesota Population Center, Integrated public use microdata series, international: Version 6.3 [Machine-readable database]. University of Minnesota, Minneapolis, 2014). Our analyses unveil a substantial amount of spatial heterogeneity both within and across countries. Despite the spectacular rise in cohabitation, its regional patterning has remained relatively unchanged over the last decades, which points to the presence of geo-historical legacies in the present patterns of unmarried cohabitation

Isolation and characterization of highly polymorphic microsatellite markers in Hypochaeris radicata (Asteraceae)

Item does not contain fulltextWe developed five highly polymorphic dinucleotide microsatellite loci for the grassland species Hypochaeris radicata (Asteraceae). Polymorphism of these markers was examined in six populations in the Netherlands. All loci were polymorphic in all populations. The number of alleles per locus varied between 18 and 43. Expected heterozygosity was between 0.86 and 0.91. Cross-species amplification was tested in six Hypochaeris species and was successful for three different loci in four species. These microsatellites are a useful tool in population genetic, dispersal and metapopulation studies or in testing levels of inbreeding

The effect of nutrient enrichment of either the bank or the surface water on shoreline vegetation and decomposition

Riparian ecosystems can harbor great diversity and provide important ecological functions such as improving water quality. The impact of eutrophication on riparian ecosystems, however, is unclear. We conducted a mesocosm experiment to study the effects of nutrient loading on riparian ecosystems. We specifically asked whether the source of nutrients in the riparian zone affects the complex interactions that occur between surface water and adjacent wetlands. We also studied litter decomposition in the wetland component of the mesocosms, because litter accumulation in fens is assumed to control succession toward floating mats. Each mesocosm consisted of an upland component, referred to as the bank, and a water compartment. The bank and water compartments were planted with typical riparian zone and open water fen species prior to the addition of nitrogen (N) and phosphorus (P) in different combinations to either the bank or the surface water. Nutrient addition (mainly P) resulted in increased plant production and higher expansion rates of plants on the bank and in the water. There were also clear interactions in plant responses between the bank and water. Only eutrophic species increased shoot densities after fertilization. Nutrient addition further resulted in higher litter production, especially on the banks, and stimulated decomposition. Both the plant responses and the litter experiment indicated that eutrophication would accelerate succession to floating mats. Such floating fen mats are not likely to have the typical species-rich combination of desirable species; however, as our results suggest that they would be dominated by a few eutrophic species.