The Effect of Urbanization on Ant Abundance and Diversity: A Temporal Examination of Factors Affecting Biodiversity

Abstract

Numerous studies have examined the effect of urbanization on species richness and most studies implicate urbanization as the major cause of biodiversity loss. However, no study has identified an explicit connection between urbanization and biodiversity loss as the impact of urbanization is typically inferred indirectly by comparing species diversity along urban-rural gradients at a single time point. A different approach is to focus on the temporal rather than the spatial aspect and perform “before and after” studies where species diversity is cataloged over time in the same sites. The current study examined changes in ant abundance and diversity associated with the conversion of natural habitats into urban habitats. Ant abundance and diversity were tracked in forested sites that became urbanized through construction and were examined at 3 time points - before, during, and after construction. On average, 4.3±1.2 unique species were detected in undisturbed plots prior to construction. Ant diversity decreased to 0.7±0.8 species in plots undergoing construction and 1.5±1.1 species in plots 1 year after construction was completed. With regard to species richness, urbanization resulted in the permanent loss of 17 of the 20 species initially present in the study plots. Recovery was slow and only 3 species were present right after construction was completed and 4 species were present 1 year after construction was completed. The second objective examined ant fauna recovery in developed residential lots based on time since construction, neighboring habitat quality, pesticide inputs, and the presence of invasive ants. Ant diversity was positively correlated with factors that promoted ecological recovery and negatively correlated with factors that promoted ecological degradation. Taken together, these results address a critical gap in our knowledge by characterizing the short- and long-term the effects of urbanization on the loss of ant biodiversity.

Diversidade de formigas urbanas (Hymenoptera: Formicidae) de dez cidades do sul do Brasil

“…A ameaça que o processo de urbanização representa para a biodiversidade em geral é bem documentada e é necessário entender os impactos causados por esse processo que resulta na perda da biodiversidade (McKinney 2002, Galindo-Leal & Câmara 2003, Buczkowski & Richmond 2012). O presente estudo amplia a compreensão sobre a diversidade de formigas da região austral do Domínio Mata Atlântica, estendendo a área de ocorrência de algumas espécies de formigas.…”

Initial conditions during Technosol implementation shape earthworms and ants diversity

“…In fact, we observed a significant relationship between age and abundance/density only in Technosols with the initial input of topsoil, an example of the importance of Technosols initial conditions for both ants and earthworms (H2). As proposed by the conceptual framework of soil colonization by soil organisms and soil formation (Jenny, 1994), a positive effect of time on abundance/density has been previously documented in post-mining reclamation sites (Hendrychová,Šálek, Tajovský, &Řehoř, 2012;Hlava & Kopecký, 2013) and urban areas (Brown, Miller, Brewster, & Fell, 2013;Buczkowski & Richmond, 2012;Smetak et al, 2007). However, those studies did not strictly investigate the effect of initial conditions which could profoundly change the trajectories of soil formation.…”

Long-term impacts of Argentine ant invasion of urban parks in Hiroshima, Japan

“…To date, numerous studies have been undertaken at different sites for better understanding of the effect of urbanization on ant diversity in urban. However, it is difficult to assess the effect of urbanization on ant diversity in urban environments in isolation because different sites have subtle differences as microhabitat characteristics (Buczkowski and Richmond 2012). According to Porter and Savignano (1990), invasion of the fire ant Solenopsis invicta in the southeastern USA had a negative impact on the populations of other insects, particularly native ants, in the region.…”

“…However, given the difficulties associated with conducting long-term observations in urban environments, the amount of ecological data collected in urban environments is typically limited (Buczkowski and Richmond 2012). Consequently, most of the studies on ants in urban environments have been 124 using long-term data.…”