Herbivory and leaf expansion of Cyathea phalerata Mart. (Cyatheaceae) in subtropical Atlantic Forest, southern Brazil

Herbivory is an interaction with great impact on plant communities since relationships between herbivores and plants are fundamental to the distribution and abundance of species over time and space. The aim of this study was to monitor the rate of leaf expansion in the tree fern Cyathea phalerata and evaluate the damage caused by herbivores to leaves of different ages and whether such damage is related to temperature and precipitation. The study was performed in a subtropical Atlantic Forest fragment located in the municipality of Caraá, in the northeast hillside of Rio Grande do Sul state, in southern Brazil. We monitored 24 mature individuals of C. phalerata with croziers in a population of approximately 50 plants. Leaf expansion rate, percentage of damaged leaves and leaf blade consumption rate by herbivory were calculated. Monthly means for temperature and accumulated rainfall were calculated from daily data. Croziers of C. phalerata were found to expand rapidly during the first and second months after emergence (3.98 cm day-1; 2.91 cm day-1, respectively). Damage caused by herbivory was observed in all of the monitored leaves, but none of the plants experienced complete defoliation. The highest percentage (57%) of damaged leaves was recorded at 60 days of monitoring, and also the highest monthly consumption rate of the blade (6.04%) occurred with young, newly-expanded leaves, while this rate remained between 1.50 and 2.21% for mature leaves. Rates of monthly leaf consumption and damaged leaves showed positive and strong relationship with each other and with temperature. The rapid leaf expansion observed for C. phalerata can be considered a phenological strategy to reduce damage to young leaves by shortening the developmental period and accelerating the increase of defenses in mature leaves.

Elemental sulfur recommendation for pH reduction in soils from Southern Brazil

ABSTRACT The elemental sulfur (S0) application may reduce soil pH, benefiting plants adapted to acid conditions and lessening problems of overliming. Nevertheless, there is no official recommendation for its application. The objective of the study was to quantify the S0 doses required to reduce the pH of soils from Southern Brazil. The experiment was carried out in the laboratory in a factorial scheme (5 × 5), with a completely randomized design and three replicates. The treatments consisted of five soils, and five doses of S0, corresponding to 0, 50, 100, 150, and 200% of the estimated dose need to reach pH 4.0. The applied doses of S0 resulted in reduction of pH and base saturation (V%) and increase of potential acidity (H + Al). These effects, however, were reduced due to the low rate of oxidation of the S0 applied (0.76-3.36%). The soil variables correlated with S0 oxidation were Mg2+ (0.86***), Al3+ (-0.82***), H + Al (-0.89***), V% (0.68***) and aluminum saturation (m%) (-0.87***). In the evaluated soils the oxidation of 50 kg ha-1 of S0 was required to reduce one unit of pH in H2O.

The Serra Spanish mackerel fishery (Scomberomorus brasiliensis – Teleostei) in Southern Brazil: the growing landings of a high trophic level resource

In fisheries, the phenomenon known as fishing down food webs is supposed to be a consequence of overfishing, which would be reflected in a reduction in the trophic level of landings. In such scenarios, the resilience of carnivorous, top predator species is particularly affected, making these resources the first to be depleted. The Serra Spanish mackerel, Scomberomorus brasiliensis, exemplifies a predator resource historically targeted by artisanal fisheries on the Brazilian coast. The present work analyzes landings in three periods within a 50-year timescale on the Parana coast, Southern Brazil, aiming to evaluate whether historical production has supposedly declined. Simultaneously, the diet was analyzed to confirm carnivorous habits and evaluate the trophic level in this region. Surprisingly, the results show that from the 1970’s to 2019 Serra Spanish mackerel production grew relatively to other resources, as well as in individual values. The trophic level was calculated as 4.238, similar to other Scomberomorus species, consisting of a case where landings increase over time, despite the high trophic level and large body size of the resource. The results agree with a recent global assessment that has demystified a necessary correlation between high trophic level and overexploitation, but possible factors acting on the present findings are discussed.

Molecular screening of Bartonella in free-ranging capybaras (Hydrochoerus hydrochaeris) from Paraná State, Southern Brazil

Bartonella is an emerging group of facultative intracellular bacteria causing circulatory and systemic disorders. Hosts for Bartonella are mostly mammals, specifically rodents, having a growing number of Bartonella species related to their infection. Capybaras (Hydrochoerus hydrochaeris) are abundant native rodents of Brazil, commonly found in urban parks. In the present study, we aimed to perform molecular screening of capybaras for Bartonella spp. Blood samples were collected from 17 free-ranging animals captured in Paraná State, Southern Brazil. None of the collected samples tested positive for the Bartonella-nuoG gene by quantitative polymerase chain reaction (qPCR), although all of them successfully amplified the mammal endogenous glyceraldehyde-3-phosphate dehydrogenase (gapdh) gene. Additionally, all animals were infested exclusively by Amblyomma dubitatum ticks at the time of sampling. This study was part of an active surveillance program, which is critical for monitoring animal health status, particularly in capybaras.

The emergence of two distinct SARS-CoV-2 Gamma related variants during the second wave of COVID-19 in Santa Catarina, Southern Brazil and the rapid spread of P.1-like-II SARS-CoV-2 variant transmission and a regionalization in the Western region

COVID-19 has assumed significant and lasting proportions worldwide. Following initial cases in the Western mesoregion, the State of Santa Catarina (SC), southern Brazil, was heavily affected as a whole by the pandemic in early 2021. This study aimed to evaluate the dynamics of the SARS-CoV-2 virus spreading patterns in the SC state through March 2020 to April 2021 using genomic surveillance. During this period, 23 distinct variants, including two VOCs (Beta and Gamma) were identified, among which, the Gamma and related lineages were predominant in the second pandemic wave within SC. However, a regionalization of P.1-like-II in the Western region was observed, concomitant to the increase in cases, mortality, and case fatality rate (CFR) index. This is the first evidence of the regionalization of the SARS-CoV-2 transmission in the and highlight the importance of tracking variants, dispersion and their impact of SARS-CoV-2 on the public health system in Brazilian states.