fluvial responses to external and internal forcing: Upper Holocene dynamics in a low latitude semi-arid region in South America

Past riverine connectivity effects in population structure and distribution of an endemic freshwater fish from northeastern Brazilian rivers: Phylogeographic, taxonomic, and conservation implications

“…Our results indicate that divergence within the two clades of C. bahiense dates from the transition between the Middle and Upper Pleistocene, when the São Francisco River adjusted its current course. Thus, our results (lineage separation in C. bahiense, mtDNA haplotype networks, and AMOVA) support the hypothesis that environmental changes through the formation of the current course of the São Francisco River, as well as its palaeocourse, associated with a low dispersal capacity due to biological attributes of the species possibly triggered the current isolation between CB1 and CB2.In addition to historical changes in the course of São Francisco River, the area of occurrence of C. bahiense also experienced major geomorphological restructuring due to neotectonics adjustments and intense erosional processes during glaciation times(Lima et al, 2021;Souza et al, 2011). The rivers where populations of CB1 occur have at least part of their drainage network influenced by the semi-arid climate (i.e., upper, and middle course of the coastal basins of the NMAF; Salitre River, SF; and Piauí River, PR), and they may have been influenced by climatic fluctuations in the drainage rearrangement process.…”

“…In addition to historical changes in the course of São Francisco River, the area of occurrence of C. bahiense also experienced major geomorphological restructuring due to neotectonics adjustments and intense erosional processes during glaciation times (Lima et al, 2021; Souza et al, 2011). The rivers where populations of CB1 occur have at least part of their drainage network influenced by the semi‐arid climate (i.e., upper, and middle course of the coastal basins of the NMAF; Salitre River, SF; and Piauí River, PR), and they may have been influenced by climatic fluctuations in the drainage rearrangement process.…”

Genesis and Distribution of Low Fluvial Terraces Formed by Holocene Climate Pulses in Brazil

“…In total, the absolute dating of 114 Optically Stimulated Luminescence (OSL) surface cover samples associated with low river terraces were employed in the present study. In detail, all data collected from 30 rivers were obtained by the Environmental Analysis and Territorial Dynamics of the Laboratory of Geomorphology and Environmental Analysis IG-UNICAMP [27,34,36,37,41,42,44,[66][67][68][69][70][71][72][73].…”

“…Regarding the southern coast of Brazil, we used data from the surficial covers of low terraces located on coastal plains associated with the mouth of the Araranguá (see box G) [36,76] and Itapocu (see box G) [73] rivers. Within the scope of the continental morphological compartments of Northeast Brazil, absolute ages correspond to surficial covers associated with low terraces located at the middle course of the Itapicuru (see box C of Figure 1) [42,69,72] and Grande (see box B) rivers, both in the Southern Sertaneja Depression. Meanwhile, the areas analyzed in Southeast Brazil are associated with the Paulista Peripheral Depression [27,34,37], the Paulista Western Plateau [34,68], and the Uberlândia-Uberaba plateau on the edge of the Brazilian Central Plateau [70].…”

“…However, these complex responses concerning Tropical Rivers (TR) and Holocene Climate Pulses (HCP), are still largely unexplored and contrast with the greater progress in studies focusing on the complexities in large river systems (Basin area > 10 6 km 2 ) [27][28][29][30][31]. In addition, climate inputs can generate different responses that depend on the attributes and spatial dimensions of the river system, indicating that smaller rivers hold important continental records on the Holocene paleoclimate events due to their greater sensitivity to subtle disturbances [11,20,[32][33][34][35][36][37][38][39][40][41][42][43][44].…”