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In central Argentina, the annual rainfall regime shows increasing since the 2nd half of the 20th century. The aim of this work was to evaluate the long-term changes in the intensity of rainfall in the central-north region of Entre Ríos between 1945 and 2019, based only on daily precipitation records aggregated at yearly, monthly and seasonal levels. We used monthly rainfall data for the period 1945–2019 from 6 localities in Province of Entre Rios, Argentina. The change detection analysis has been conceded using Pettitt’s test, von Neumann ratio test, Buishand’s range test and standard normal homogeneity (SNH) test, while non-parametric tests including linear regression, Mann-Kendall and Spearman rho tests have been applied for trend analysis. Like the regional results, this study observed a sustained increase in monthly rainfall to the breaking point in the 1970s, but then the annual rate of increase was even higher. The average annual rainfall in the region prior to that date was 946 mm, while after the same 1150 mm, equivalent to 21.5% higher than the 1945–1977 average and 8.5% higher according to the historical average 1945–2019.

La estabilidad de los ecosistemas está directamente relacionada con un alto valor de biodiversidad y, en este sentido, los efectos antrópicos han generado condiciones negativas sobre los pastizales naturales. El objetivo del trabajo fue evaluar la respuesta del pastizal natural de un bosque nativo degradado del Espinal argentino con arbustivas por medio de un control químico aéreo en un sistema ganadero con pastoreo rotativo de baja carga instantánea. El estudio se realizó en el Área Natural Protegida Reserva de Usos Múltiples Estancia "El Carayá" ubicada en el centro-norte de Entre Ríos, Argentina. Se realizaron 16 evaluaciones desde el año 2012 al 2015 sobre el sector tratado químicamente con Picloram+2,4-D y tres sectores sin tratamiento. En cada evaluación se cuantificó la cobertura vegetal, la composición florística de las especies forrajeras más representativas y la biomasa vegetal, comparadas mediante pruebas no paramétricas. Los resultados de este trabajo comprueban que la utilización de una técnica de control químico aéreo aumentó significativamente, un 44%, la cobertura y biomasa en las áreas tratadas de las especies forrajeras respecto al testigo. El control químico sobre las arbustivas persistió en el tiempo con una efectividad considerable durante los años de evaluación. Por otro lado, la composición florística de las especies herbáceas no presentó diferencias significativas entre tratamientos.

In forests, it is possible to sequester the carbon emitted by industrial activities, although global deforestation has recently increased considerably. Protected Areas make a significant contribution to mitigate negative effects of climate change. In this sense, the aim of this study is to estimate the carbon storage of the different types of subtropical native forests in the Protected Area «Estancia El Caraya» (hereinafter – PA «El Caraya»), located in the Mesopotamian Spinal. The study was carried out in the province of Entre Rios, Argentina. We evaluated the carbon stock in the soil and herbaceous, shrub and tree components of five various environments with native forests as the dominant biome. The soil component represented 81% of the carbon stock in native forest, while the remaining percentage is distributed in trees (11%), shrubs (6%), and herbaceous vegetation (2%). Native forest of PA «El Caraya» stores 0.974 t C × km-2 (3.56 t CO2 × km-2), 39.4% less than the world average in this conservation category. These differences are due to the high heterogeneity of the natural environments in the world due to the very diverse ecological conditions. Proper management practice of subtropical native forests in the Spinal Mesopotamian contributes highly to reduction of carbon in atmosphere. Application of forest management techniques in Protected Areas allows obtaining sustainable forests that maximise the potential of this area.

DOI: 10.26650/forestist.2018.392323The invasion of woody plants in variousparts of the world has been a longstanding concern in livestock production dueto the expected negative impact on secondary production. Native forests cover30% of the earth’s land surface. A great part of the livestock production ofEntre Ríos is developed in these ecosystems, which have been highly degradeddue to inadequate cattle management, and the invasion of shrub species. The aimof this study was to evaluate the natural pasture recovery in a degraded nativeforest, subjected to a mechanical intervention with a frontal roller-chopping,in order to increase the grazing area and improve secondary productivity. Thestudy was carried out in Paraná Department (Entre Ríos, Argentina). On15/12/2014 a mechanical intervention was carried out with a frontalroller-chopping designed by the Chair Ecology of Agricultural Systems. Toevaluate the dynamics of the recovery of the natural grassland of the nativeforest, seven measurements were made on the following dates: 15/05, 12/06,28/07, 11/09, 27/10 and 21/12/2015, and 22/02/2016. The vegetation cover wasmeasured with the line intercept method and phytomass production. In each ofthe evaluations, forage species cover was higher in the mechanically intervenedarea, presenting significant differences with respect to the control andregistering an average relative increase of 47% at the end of the trial. In thesection where mechanical intervention had been made, the coverage of Baccharispunctulata showed a marked decrease during all the measurements with respect tothe control, obtaining an average decrease of 91.8% at the end of the sampling.Mechanical intervention enables the cover of shrubs that compete with naturalgrassland in a degraded native forest to be reduced, while also recoveringforage vegetable species and thus improving primary production, due to a raisein the forage availability because of increased grazing area., DOI: 10.26650/forestist.2018.392323Dünyanın çeşitli yerlerinde odunsubitkilerin işgali, ikincil üretim üzerinde beklenen olumsuz etki nedeniylecanlı hayvan üretiminde uzun zamandır devam eden bir endişe kaynağı olmaktadır.Yerli ormanlar dünyanın toprak yüzeyinin %30’unu kaplamaktadır. Entre Ríos’unhayvancılık üretiminin büyük bir kısmı, yetersiz sığır yönetimine ve çalıtürlerinin istilasına bağlı olarak büyük ölçüde bozulmuş olan bu ekosistemlerdegeliştirilmiştir. Bu çalışmanın amacı, otlatma alanını arttırmak ve ikincilverimi artırmak amacıyla, önden silindirli doğrama ile mekanik müdahaleye maruzkalan, bozulmuş bir ormandaki doğal mera geri kazanımını değerlendirmektir.Çalışma Paraná Bölgesi’nde (Entre Ríos, Arjantin) gerçekleştirilmiştir.15/12/2014 tarihinde, Ziraat Sistemleri Kürsüsü Ekolojisi tarafından tasarlananbir önden silindirli doğrama makinesi ile mekanik bir müdahalegerçekleştirilmiştir. Doğal ormanın doğal otlaklarının toparlanma dinamiklerinideğerlendirmek için, aşağıdaki tarihlerde yedi ölçüm yapılmıştır: 15/05, 12/06,28/07, 11/09, 27/10 ve 21/12/2015 ve 22/02/2016. Bitki örtüsünün örtü hattıkesilme yöntemi ve fitoma üretimi ile ölçülmüştür. Değerlendirmelerin herbirinde, yem türlerinin örtüleri mekanik olarak müdahale edilen alanda dahayüksek bulunmuş olup, kontrol açısından önemli farklılıklar göstermiştir.Deneme çalışması sonunda ortalama %47’lik bir nispi artış kaydedilmiştir.Mekanik müdahalenin yapıldığı bölgede, Baccharis punctulata’nın kapsamı, tümölçümler sırasında kontrol açısından belirgin bir düşüş göstermiştir veörneklemenin sonunda %91,8’lik bir ortalama düşüş elde edilmiştir. Mekanikmüdahale ile bozulmuş otlak alanlardaki doğal otlakla rekabet eden çalı örtüsüazaltılmış, aynı zamanda otları bitki türlerini geri kazanarak, otlatmaalanlarındaki yem artışı nedeniyle birincil üretimi iyileştirmektedir.

Las hormigas cortadoras de hojas (HCH) son ampliamente conocidas por ser “ingenieros del ecosistema” debido a las modificaciones que causan en los suelos al construir sus nidos. Determinamos la variación espacial de la resistencia mecánica a la penetración (RMP) del suelo generada por nidos de la HCH Atta vollenweideri en un bosque nativo del Espinal Mesopotámico. El estudio se realizó en el Área Natural Protegida “Estancia El Carayá” (Entre Ríos, Argentina). Se seleccionaron 10 nidos de A. vollenweideri donde se registró la RMP en cinco posiciones (centro del nido, periferia del nido, a 15, 30 y 60 m del nido) por medio de dos transectas de 60 m en cada nido, con dirección aleatoria. Luego se realizó una interpolación de cada penetración en un perfil longitudinal de isovalores de RMP, para lo cual utilizamos el método de ponderación de distancia inversa. La RMP aumentó ~30% a los 40 cm de profundidad del suelo sobre el centro de los nidos respecto a su periferia. Por otro lado, la RMP aumentó de forma considerable sólo en los primeros 10 cm de profundidad en el centro del nido. Los nidos de A. vollenweideri modifican las propiedades físicas de los suelos, sustrato que puede ser potencialmente empleado por otros organismos. Esto ilustra el papel de estas hormigas como ingenieros del ecosistema. Leafcutter ants (LCA) are widely being “ecosystem engineers” due to changes in the soil caused by theconstruction of their nests. We determined the spatial variation of mechanical resistance to penetration (MRP)of a modified soil Alfisol with LCA in a native forest to Mesopotamian Espinal. The study was conducted inthe Natural Protected Area “Estancia El Carayá” (Entre Ríos, Argentina). 10 nests A. vollenweideri where MRPwas recorded in five positions (center of the nest, the nest periphery, 15, 30 and 60 m from the nest) by twotransects each nest 60 m were selected with random direction. Then an interpolation of each penetration wasperformed in a longitudinal profile isovalues MRP, using the method of inverse distance weighting. The MRPincreased ~30% at 40 cm soil depth over the center of the nest about its periphery. On the other hand, the MRPincreased significantly only in the first 10 cm deep in the center of the nest. Nests to A. vollenweideri modify thephysical properties of soils, substrates that can be potentially used by other organizations, illustrating theirrole as ecosystemic engineers.