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Biological invasions are one of five direct drivers of global change that act synergistically threatening biodiversity and the provision of ecosystem services globally. In this work we compile the list of exotic woody species that have been introduced in Argentina, we characterize them according to their geographical origin, use, foliage phenology, reproduction, dispersal, and we analyse their geographical distribution within Argentina. Based on the bibliography, we identify those species that are currently or potentially problematic for Argentina. Most of the species are native to Eurasia and the main reason for their introduction was their ornamental use. They are mostly monoecious, with deciduous leaves, without vegetative reproduction, with fleshy fruits and dispersed by animals. The area corresponding to the Yungas, the Paranaense Forest and the Humid Chaco presents the largest number of exotic species; the area corresponding to the Espinal and Dry Chaco has the largest number of currently problematic species and, together with the Pampeana area, the largest number of potentially problematic species. Finally, we propose actual problematic species in areas without native trees and potentially problematic species with broad distribution in Argentina should be monitored and probably managed among the studied species. [ABSTRACT FROM AUTHOR]

Annual productivity of croplands can be increased by intensifying cropping sequences and fine-tuning agronomic management, improving the ratio between seasonal grain yield and annual available resources. The aims of this study were to evaluate, for different crop sequences and agronomic practices, (i) grain yield (GY), and energy of GY (EY) on annual basis; (ii) the relative contribution of each crop to the annual GY and EY of the crop sequences; and (iii) the maximum attainable annual EY. In a five-year field experiment at the central Rolling Pampa of Argentina, three crop sequences: soybean mono-cropping (Sy), a two-year rotation alternating maize and soybean (Mz-Sy), and a three-year rotation including wheat/soybean, maize, and soybean (Wt/Sy-Mz-Sy) were evaluated under the presence of either fallow (F) or cover crops (CC) during winter, and under two agronomic systems: conventional (CM) and intensified management (IM). For EY, Mz-Sy and Wt/Sy-Mz-Sy sequences greatly surpassed (P < 0.01) Sy (78% and 86% higher) across all years. The CC negatively affected (P < 0.001) the annual GY of the sequences by mostly affecting maize GY (−14% than under F), but this effect varied with the experimental year (rainfall levels) and CC composition (grass/legume proportion). The annual GY of the Mz-Sy (6.47 Mg ha−1) and Wt/Sy-Mz-Sy (6.69 Mg ha−1) sequences increased (P < 0.001) in the IM system compared to CM (5.33 and 5.64 Mg ha−1). In addition, under IM the penalty of CC on the annual GY of the crop sequences was lower (−7%) than under CM (−14%). From the combination of crop sequences and agronomic systems, the highest annual EY corresponded to the more intensified Wt/Sy-Mz-Sy sequence under IM (176 GJ ha−1), doubling the lowest EY obtained by soybean mono-cropping under CM (87 GJ ha−1). This result highlights the opportunity for intensification of cropping sequence and agronomic management to increase the annual productivity of the existing cropping area. • More diverse crop sequences surpassed soybean mono-cropping in annual grain yield. • Cover crops negatively affected grain yield of crop sequences by mostly affecting maize yields. • Intensified management system increased annual grain yield of crop sequences. • Intensified management system minimized cover crop penalties on annual grain yield of the sequences. • Wheat/soybean-maize-soybean rotation under the intensified management had the highest annual grain yield. [ABSTRACT FROM AUTHOR]

Peperomia nitida and P. armondii (Piperaceae, subgen. Rhyncophorum) are recorded for the first time for the Argentinean flora in the province of Misiones. The species are described and illustrated, and their geographical distributions are updated. A key to distinguish the Argentinean species of subgen. Rhyncophorum is included, and P. elongata is excluded from the Argentinean Flora. [ABSTRACT FROM AUTHOR]

The Teyú Cuaré Provincial Park is located in the department of San Ignacio, Misiones, Argentina (27º 16′ S, 55º 33′ W) and is 78 ha in area. The studied area has a total of 659 species of vascular plants, 384 genera and 110 families, 15 of which are Pteridophytes, 18 Monocotyledons and 77 Dicotyledons. Four of these species are endemic to the park and other 19 are restricted to Argentina, in the area included by this work. The families with the largest number of species are Poaceae, Fabaceae and Asteraceae; the richest genera are Paspalum and Panicum. Only 14 species are adventive. Our results show the great richness of species and the singularity of the flora of the park. [ABSTRACT FROM AUTHOR]