Temporal and spatial variation of Myriapoda (Diplopoda and Chilopoda) assemblages in a Neotropical floodplain

Abstract

Myriapods constitute important edaphic macrofauna taxa which dwell in different trophic levels and influence the dynamics of these environments. This study evaluated the variation in composition, richness and abundance of edaphic myriapod assemblages as a function of the distribution and structure of flooded and non-flooded habitats (spatial variation) and hydrological seasonality (temporal variation) in a floodplain of the northern Pantanal region of Mato Grosso, Brazil. Sampling was carried out in three areas of the Poconé Pantanal, along an altitudinal and inundation gradient consisting of inundated and non-inundated habitats and different vegetation formations. Three quadrats (10 x 10 m) were delimited within each habitat type, where sampling was performed using pitfall traps and mini-Winkler extractors during the dry, rising water, high water and receding water periods of two hydrological cycles within the Pantanal (2010/2011 and 2011/2012). A total of 549 millipedes were collected, consisting of 407 Diplopoda and 142 Chilopoda distributed in six orders, 12 families and 20 species. The assemblages composition varied throughout the seasonal periods, indicating that the rising water and dry periods differed from the high water and receding water periods. In addition to the variation between seasonal periods, myriapod richness and abundance also varied in relation to areas consisting of different vegetation formations. Thus, it can be concluded that the hydrological seasonality associated with the inundation gradient and different vegetation types were determinant in the heterogeneous spatial and temporal distribution of myriapod assemblages, validating that the conservation of these invertebrates in the Pantanal is directly linked to the preservation of vegetation, and consequently, ecosystem integrity.

Myriapods (Arthropoda, Myriapoda) in the Pantanal of Poconé, Mato Grosso, Brazil

“…The majority of species corresponds to large-sized individuals, which are thus more easily collected, corroborating Golovatch et al (2005). The same was described in recent studies on Chilopoda (Battirola et al 2017, Santos-Silva et al 2018a). These results can explain why the Symphyla and Pauropoda showed a lower number of species in studies conducted in that region: probably because these myriapods are small-sized, have little mobility, and are associated with the soil organic layers, their sampling is more difficult.…”

“…In the Pantanal of Poconé, the Myriapoda fauna has considerable species richness; however, to the present date, it has been characterized by the dominance of few taxa (Golovatch et al 2005, Santos-Silva et al 2018a). The majority of species corresponds to large-sized individuals, which are thus more easily collected, corroborating Golovatch et al (2005).…”

“…For the Pantanal of Poconé, Spirostreptidae, Paradoxosomatidae, and Chelodesmidae predominate among the Diplopoda, while the Scolopendridae prevail among the Chilopoda, characterizing the assemblage as containing large-sized individuals and a smaller number of species in each habitat (e.g. Golovatch et al 2005, Scheller 2007, Battirola et al 2017, Santos-Silva et al 2018a). An example of such variation can be verified in the Myriapod species richness of the Ducke Reserve near the city of Manaus, Central Amazon, whose 73 species occurring in the area are divided into 31 Pauropoda, 23 Chilopoda, 14 Diplopoda, and five Symphyla .…”

“…This clearly demonstrates the need for more in-depth knowledge of the biology and taxonomy of the species occurring in that region (Junk et al 2006), especially for poorly studied taxa with sparse information like Myriapoda (e.g. Golovatch et al 2005, Junk et al 2006, 2017, Santos-Silva et al 2018a.…”

Individual niche trajectories drive fitness variation

“…The overall positive relationship between niche trajectory length and individual‐level fitness could be due to the higher feeding rate of predators when environmental prey availability fluctuates. Indeed, our study system is dynamic and gradual changes in temperature, humidity and vegetation structure over the summer lead to shifts in the presence and abundance of important invertebrate prey for frogs (Battirola, Batistella, Rosado‐Neto, Brescovit, & Marques, ; Santos‐Silva, Pinheiro, Chagas‐Jr, Marques, & Battirola, ; Soares et al, ). Therefore, these temporal changes in prey availability may provide the scope for temporal niche variation, favouring individuals that can plastically adjust their diets to the best foraging options at a given time.…”