Synergistic Calibration of a Hydrological Model Using Discharge and Remotely Sensed Soil Moisture in the Paraná River Basin

Hydrological models are useful tools for water resources studies, yet their calibration is still a challenge, especially if aiming at improved estimates of multiple components of the water cycle. This has led the hydrologic community to look for ways to constrain models with multiple variables. Remote sensing estimates of soil moisture are very promising in this sense, especially in large areas for which field observations may be unevenly distributed. However, the use of such data to calibrate hydrological models in a synergistic way is still not well understood, especially in tropical humid areas such as those found in South America. Here, we perform multiple scenarios of multiobjective model optimization with in situ discharge and the SMOS L4 root zone soil moisture product for the Upper Paraná River Basin in South America (drainage area > 900,000 km²), for which discharge data for 136 river gauges are used. An additional scenario is used to compare the relative impacts of using all river gauges and a small subset containing nine gauges only. Across the basin, the joint calibration (CAL-DS) using discharge and soil moisture leads to improved precision and accuracy for both variables. The discharges estimated by CAL-DS (median KGE improvement for discharge was 0.14) are as accurate as those obtained with the calibration with discharge only (median equal to 0.14), while the CAL-DS soil moisture retrieval is practically as accurate (median KGE improvement for soil moisture was 0.11) as that estimated using the calibration with soil moisture only (median equal to 0.13). Nonetheless, the individual calibration with discharge rates is not able to retrieve satisfactory soil moisture estimates, and vice versa. These results show the complementarity between these two variables in the model calibration and highlight the benefits of considering multiple variables in the calibration framework. It is also shown that, by considering only nine gauges instead of 136 in the model optimization, the model is able to estimate reasonable discharge and soil moisture, although relatively less accurately and with less precision than for the entire dataset. In summary, this study shows that, for poorly gauged tropical basins, the joint calibration of SMOS soil moisture and a few in situ discharge gauges is capable of providing reasonable discharge and soil moisture estimates basin-wide and is more preferable than performing only a discharge-oriented optimization process.

Hypostomus hermanni redescription and a new species of Hypostomus (Siluriformes: Loricariidae) from Upper Paraná River basin, Brazil

A redescription of Hypostomus hermanni is presented herein along with the description of a new species of Hypostomus, which is apparently endemic to the Ivaí River basin, a tributary of the Upper Paraná River basin, Brazil. Hypostomus hermanni is diagnosed from congeners mainly by having: usually large black blotches on body and fins; absence of keels on compound pterotic, on pre-dorsal plates, and on lateral series of bony plates; by having parieto-supraoccipital and predorsal region flat; and by having less than 46 teeth per each premaxilla or dentary ramus. The new species is distinguished from congeners mainly for lacking conspicuous blotches, parieto-supraoccipital non-carinate, and villiform bicuspid teeth.

High congruence of karyotypic and molecular data on Hypostomus species from the Paraná River basin

ABSTRACTThe Hypostomini tribe comprises a single genus, Hypostomus, which possibly contains several monophyletic groups because of significant morphological variation and a variety of diploid numbers and karyotype formulas. The objective of this study was to infer evolutionary relationships among some species of Hypostomus found in the Paraná River basin and subsequently to identify chromosomal synapomorphies in the groupings formed. Two nuclear genes, rag1 and rag2, and two mitochondrial genes, mt-co1 and mt-cyb, were used to establish evolutionary relationships. Phylogenetic trees were inferred using the maximum likelihood (ML) method for mt-co1 and Bayesian analysis (BA) for all genes concatenated. Both phylogenetic trees showed two large monophyletic clades within Hypostomus. These clades are based on chromosome number, where haplogroup I contains individuals with 66–68 chromosomes, and haplogroup II contains species with 72–80 chromosomes. A third monophyletic haplogroup was also observed using ML, formed by H. faveolus and H. cochliodon, which present 2n = 64, reinforcing the separation of groups in Hypostomus by diploid number. Robertsonian rearrangements were responsible for forming the different diploid numbers and for the diversity of karyotype formulas. The groups based on traditional morphological taxonomy are considered artificial in this study; the staining pattern, which separates the two large groups morphologically and is supported by little chromosomal evidence, was instead determined to show homoplasy. Ag-NORs are predominantly multiple and located on st/a chromosomes, along with 18S rDNA sites; 5S rDNA sites are often seen in an interstitial position, following the trend already described for vertebrates.

AGROCLIMATIC RISK ZONING FOR GUAVA (Psidium guajava L.) IN PARANÁ RIVER BASIN 3

Fruticulture constitutes an important sector of the Brazilian agricultural industry. Despite technological and scientific advances, climate is still the most important variable defining crop productivity. Because of this, agroclimatic zoning should be one of the first factors to consider when starting to plant a particular crop. The objective of this work was to conduct climate risk zoning for guava (Psidium guajava L.) in Paraná river basin 3, Paraná, Brazil, using meteorological data from 43 stations collected between 1976 and 2018. The climate risk analysis was based on the climatic factors that impact the species, such as rainfall, annual water deficit, average annual temperature, coldest month temperature, and risk of frost. The findings of this study suggest that the basin has areas with a low climate risk for guava cultivation. Precipitation and water balance were sufficient under all tested scenarios. The most limiting factor for production was frost, but with risk only present during the first years of cultivation. Despite this, planting restrictions were only predicted to occur in the far west portion of the basin. Agricultural techniques that reduce the risk of frost and avoiding areas with greater frost incidences are the two most important aspects to consider to ensure greater success for guava in the region.