Geographic variations of seasonality and coexistence in communities: The role of diversity and climate

Abstract

One of the most conspicuous and widely analyzed patterns in ecology is the latitudinal gradient in species richness. Over the 200 years since its recognition, several hypotheses have accumulated in order to account for spatial variations in diversity. Geographic variations in seasonality have been repeatedly proposed as a determinant of community richness. However, the geographic structure of community seasonality has not yet been analyzed. In the present work we evaluated three hypotheses that account for variations in the temporal structuring of communities: first, environmental seasonality determines community seasonality; second, community richness determines its degree of structuring; and third, the presence of an increase in species segregation with latitude, reflected in a pattern of species negative co-occurrence. The hypotheses were evaluated using path analysis on 29 amphibian communities from South America, connecting latitude, environmental conditions, diversity, seasonality, and coexistence structure -nestedness and negative co-occurrence -within communities. Latitude positively affects community seasonality through an increase in temperature seasonality, but a weak negative direct effect suggests that other variables not considered in the model -such as the strength of biotic interactions -could also be involved. Both latitude and diversity (directly and indirectly) determine an increase in negative co-occurrence and nestedness. This suggests that groups of species that are mutually nested in time are internally segregated. Further, the strength of this structure is determined by community diversity and latitude. Temporal structuring of a community is associated with latitude and diversity, pointing to the existence of a systematic change in community organization far beyond, but probably interrelated, with the recognized latitudinal trend in richness. The available information and analysis supported the three hypotheses evaluated.

Beta diversity of marine bacteria depends on temporal scale

“…B3A, B). The relationship between the strength of community and environmental turnover has also been observed in the seasonal dynamics of amphibians across latitudes (Canavero et al 2009), and thus is not limited to marine microorganisms.…”

Diversidade local e influência da sazonalidade sobre taxocenoses de anfíbios e répteis na Reserva Extrativista Chico Mendes, Acre, Brasil

“…Oda et al, 2009;São-Pedro & Feio, 2010;Kopp et al, 2010;Ferreira et al, 2012;Venâncio et al, 2014). Esta relação se deve à dependência dos anfíbios aos ambientes úmidos tanto para manutenção das condições fisiológicas quanto para reprodução (Hatano et al, 2002;Both et al, 2008;Canavero & Arim, 2009;Cole et al, 2014). A maioria das espécies de anfíbios que possuem reprodução explosiva ou restrita a poucos meses do ano sincronizam suas atividades com o período chuvoso , permitindo assim uma maior taxa de sobrevivência e aptidão (Visser et al, 2009).…”

“…A influência de fatores climáticos é conhecida tanto para anfíbios (Oda et al, 2009;São Pedro & Feio, 2010;Kopp et al, 2010;Ferreira et al, 2012;Venâncio et al, 2014), quanto para répteis (Colli, 1991;Vitt et al, 1995;Daltry et al, 1998;Nicholson et al, 2005;Vitt et al, 2008;Huey et al, 2009;Carlson et al, 2014). De forma geral, ambos os grupos são sensíveis às grandes variações nas condições climáticas, sendo estas limitantes principalmente em relação às estratégias reprodutivas (Vitt et al, 1994;Duellman, 1999;Hatano et al, 2002;Bernarde & Abe, 2006;Both et al, 2008;Canavero et al, 2009) e de forrageio (Bernarde & Abe, 2006;Huey et al, 2009;Hartmann et al, 2009), podendo variar entre regiões (Menin et al, 2008;Heatwole & Sexton, 2012;Rocha et al, 2014), entre espécies e entre o sexo e fases ontogenéticas (Nicholson et al, 2005;Bernarde & Abe, 2006;Menin et al, 2008;Cole et al, 2014).…”

Climatic variables and altitude as predictors of anuran species richness and number of reproductive modes in Brazil

“…Although temperature is often correlated with breeding activities of anuran species throughout the year in the Neotropical region (Canavero et al 2008, Duellman & Trueb 1994, Vasconcelos & RossaFeres 2005, it is believed that this variable plays a secondary role in the regulation of reproductive activity of anurans (Heyer 1973), because it is probably correlated with rainfall occurrence, mainly in regions with climatic seasonality (Santos et al 2007, Toledo et al 2003, Vasconcelos & Rossa-Feres 2005. Despite this probable secondary importance of temperature, a stronger influence of this variable on anuran assemblages might be recorded in future studies with the inclusion of more localities in the southernmost Brazilian region, because while variation in precipitation decreases, temperature markedly increases its seasonality at higher latitudes, which in turn influences anuran activities at these locations (Canavero et al 2009). …”