Spatial-temporal dynamics of neotropical velvet ant (Hymenoptera: Mutillidae) communities along a forest-savanna gradient

Abstract

Understanding how and why biological communities are organized over space and time is a major challenge and can aid biodiversity conservation in times of global changes. Herein, spatial-temporal variation in the structure of velvet ant communities was examined along a forest-savanna gradient in the Brazilian Cerrado to assess the roles of environmental filters and interspecific interactions upon community assembly. Velvet ants were sampled using 25 arrays of Y-shaped pitfall traps with drift fences for one year along an environmental gradient from cerrado sensu stricto (open canopy, warmer, drier) to cerradão (closed canopy, cooler, moister). Dataloggers installed on each trap recorded microclimate parameters throughout the study period. The effects of spatial distances, microclimate parameters and shared ancestry on species abundances and turnover were assessed with canonical correspondence analysis, generalized dissimilarity modelling and variance components analysis. Velvet ant diversity and abundance were higher in the cerrado sensu stricto and early in the wet season. There was pronounced compositional turnover along the environmental gradient, and temporal variation in richness and abundance was stronger than spatial variation. The dry season blooming of woody plant species fosters host abundance and, subsequently, velvet ant captures. Species were taxonomically clustered along the gradient with Sphaeropthalmina (especially Traumatomutilla spp.) and Pseudomethocina more associated, respectively, with cerrado sensu stricto and cerradão. This suggests a predominant role of environmental filters on community assemble, with physiological tolerances and host preferences being shared among members of the same lineages. Induced environmental changes in Cerrado can impact communities of wasps and their hosts with unpredictable consequences upon ecosystem functioning and services.

The role of environmental gradients and microclimates in structuring communities and functional groups of lizards in a rainforest-savanna transition area

“…In each sample plot, a data-logger (Onset HOBO U23 Pro v2 temperature/relative humidity data logger) was installed to record the air temperature and relative humidity every minute during the 15-day sampling period. Data were collected as previously described in Alvarenga et al (2017) . In general, 14 micro-climatic variables were derived of which seven are related to humidity, such as absolute maximum relative humidity (Hmaxa), absolute minimum relative humidity (Hmina), absolute standard deviation of relative humidity (Hsda), maximum relative humidity (Hmax), mean relative humidity (Hmean), minimum relative humidity (Hmin), standard deviation of relative humidity (Hsd).…”

“…Remote sensing, for instance, provides global and easily accessible data that serve as a proxy for vegetation structure and composition at different spatial scales ( Tuomisto et al, 2003a ; Tuomisto et al, 2003b ; Tuomisto et al, 2019 ; Turner et al, 2003 ; Salovaara et al, 2005 ; Rocchini et al, 2018 ). On the other hand, microclimate variables that are remotely inferred using modeling ( Algar, Morley & Boyd, 2018 ) or directly measured on the ground with data loggers ( Alvarenga et al, 2017 ) can provide greater refinement and accuracy in quantifying microhabitat variations ( Milling et al, 2018 ). Together, functional traits, remote sensing, and microclimate variables can help to better characterize species-environment interactions and distribution of organisms ( Petchey & Gaston, 2002 ; Maximiano et al, 2020 ).…”