No abstract

Although animated maps are widely promoted as ideal vehicles for learning and scientific discovery, there has been little empirical work that demonstrates their relative effectiveness in relation to static small-multiple alternatives. In this article, we attempt to clarify the issues related to the potential of animation from an explicitly geographic perspective, but one that is also grounded in broader cognitive science and human-computer interaction considerations. We compared the effectiveness of animated with static small-multiple maps, specifically in relation to map readers' ability to identify clusters that move over space and through time. In this study, we focused on several factors that might impact (or help explain) map readers' ability to correctly identify clusters. These factors included animation pace, cluster coherence, and gender. We found that map readers answer more quickly and identify more patterns correctly when using animated maps than when using static small-multiple maps. We also found that pace and cluster coherence interact so that different paces are more effective for identifying certain types of clusters (none vs. subtle vs. strong), and that there are some gender differences in the animated condition. This study is one of a small number of controlled experiments directed to the relative advantages of animated and static small-multiple maps. It provides the basis for further research that is needed to better understand the cognitive load involved in reading animated maps, to better describe and understand gender differences, and to investigate the efficacy of animated maps for other types of map reading tasks.

Changing climatic conditions are shaping how density mediates resource competition. Colonies of the seed-eating red harvester ant, Pogonomyrmex barbatus, live for about 30 years in desert grassland. They compete with conspecific neighbors for foraging area in which to search for seeds. This study draws on a long-term census of a population of about 300 colonies from 1988 to 2019 at a site near Rodeo, New Mexico, USA. Rainfall was high in the first decade of the study, and then declined as a severe drought began in about [2001][2002][2003]. We examine the effects on colony survival and recruitment of the spatial configuration of the local neighborhood of conspecific neighbors, using Voronoi polygons as a measure of a colony's foraging area, and consider how changing rainfall influences the effects of local neighborhoods. The results show that a colony's chances of surviving to the next year depend on its age and on the foraging area available in its local neighborhood. Recruitment, measured as a founding colony's chance of surviving to be 1 year old, depends on rainfall. In the earlier years of the study, when rainfall was high, colony numbers increased, and then began to decline after about 1997-1999, apparently due to crowding. As rainfall decreased, beginning in about 2001-2003, recruitment declined, and so did colony survival, leading to a trend toward earlier colony death which was most pronounced in 2016. As rainfall declined, apparently decreasing food availability, more foraging area was needed to sustain a colony: although the number of colonies declined, the impact of crowding by intraspecific neighbors increased. These processes maintain overdispersion on the scale of about 8 m, with transient clustering at larger spatial scales. In addition, other factors besides crowding, such as the colony's regulation of foraging activity to manage water loss, appear to contribute to a colony's survival. The adaptive capacity for selection on the collective behavior that regulates foraging activity may determine how the population responds to ongoing climate change and drought.

No abstract

The ejido is an institution of communal land tenure and governance administered by the Mexican government. This paper assesses the current visual appearance of landscapes and implicit land use in ejidal lands on the periphery of Guadalajara, Mexico, using Google Street View (GSV) images tagged for signs of urban distress. Distressed landscapes are associated with the temporal process of urban expansion—newer settlements tend to be more visibly impoverished. Concentrations of vulnerable housing are correlated with encroached-upon ejidal lands in a process that was underway by the 1970s, well before Mexico’s neoliberal turn. Ejidos on the urban periphery, created to support agricultural communities during Mexico’s radical period of agrarian reform, are now sites of urban sprawl and impoverishment. Nevertheless, these communities remain legally salient as federal entities with respect to the disposition of land. Their presence complicates the historical evolution of land use in the urban periphery in ways that do not fit into classical central place models. We conclude that the presence of ejidos is associated with rapid and chaotic urbanization by migrants and the loss of agricultural capacity in Guadalajara’s periphery.