Sex morphs and invasiveness of a fleshy-fruited tree in natural grasslands from Argentina

Invasiveness has usually been studied as a species-level attribute; nevertheless, phenotypic differences between individuals in a population can lead to significant variations in colonization ability. In this paper, we analyse the potential effects of sex morphs of Prunus mahaleb, a gynodioecius fleshy-fruited tree, on its invasiveness in natural grasslands in the southern Argentine Pampas. We assessed the abundance of both hermaphrodite and female plants and compared their fecundity, propagule size and germination response. We found that the females were less abundant in the invasive populations studied, apparently since the beginning of the colonization. However, our results demonstrated that at the present time females do not show any fecundity reduction, which clearly shows that P. mahaleb has established an effective interaction with generalist pollinators which compensates for the apparent disadvantage of females. Fruit set showed a wider range of variability over time in the females than in the hermaphrodites, which could be the consequence of greater susceptibility to changes in the activity of pollinators. We found no evidence of a female benefit due to reallocation of resources or better outcrossed progeny considering propagule size and germination. We discuss the relative importance of sex morphs and interactions at different stages of the invasion process.Fil: Amodeo, Martín Raúl. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zalba, Sergio Martín. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Germination of Grindelia ventanensis (Asteraceae), an endemic species from the Ventania Mountains (Buenos Aires)

Germination of Grindelia ventanensis (Asteraceae), an endemic species from the Ventania Mountains (Buenos Aires). In this paper the potential for sexual propagation of Grindelia ventanensis (Asteraceae) is evaluated. It is an endemic shrub of Ventania Mountains (Buenos Aires province) considered critically endangered and with potential economic value as ornamental species. Percentage and media term of germination of seeds were estimated from cultivated and wild populations, exposed and not exposed to cold conditions, and the effect of storage on these variables was determined. Percentage of germination of seeds from wild populations was greater (67%) than that of seeds from cultivated populations (16%), and no effect of cold was detected. Changes in the media term of germination were neither detected when considering the origin of seeds nor the application of cold. Time of storage tested (nine to ten months) significantly reduced the percentage of germination and increased its media term. Reduction in the percentage of germination associated with storage could be result of a loss of viability or an induction of a secondary dormancy. Our results indicate that G. ventanensis is a species with a good potential for its cultivation from seeds. This knowledge could contribute to the conservation of this species.Este trabajo evalúa la capacidad de propagación por semillas de Grindelia ventanensis (Asteraceae), un subarbusto endémico del sistema de Ventania (provincia de Buenos Aires). La especie es considerada en peligro crítico de extinción y presenta potencial económico como ornamental. Se estimaron el porcentaje y tiempo medio de germinación de semillas de poblaciones cultivadas y silvestres, tratadas o no con frío y se evaluó el efecto del almacenamiento sobre estas variables. El porcentaje de germinación de semillas de poblaciones silvestres (67%) resultó mayor que el de las cultivadas (16%), pero no se hallaron diferencias asociadas al tratamiento con frío. Tampoco se observaron cambios en el tiempo medio de germinación teniendo en cuenta el origen de las semillas ni la aplicación de frío. El tiempo de almacenamiento testeado (nueve a diez meses) reduce significativamente el porcentaje y la velocidad de germinación. La reducción del porcentaje de germinación asociada al almacenamiento podría atribuirse a una pérdida de viabilidad o a la inducción de una segunda dormancia. Nuestros resultados indican que G. ventanensis es una especie con buen potencial para el cultivo a través de semillas. Esta información puede contribuir a su conservación.Fil: Negrin, Vanesa Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; ArgentinaFil: Zalba, Sergio Martín. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Assessment of the conservation status of natural and semi-natural patches associated with urban areas through habitat suitability indices

Urban environments rely on the surrounding natural ecosystems remnants as providers of ecosystem functions, therefore these areas not only support a unique biodiversity but also have a social value for maintaining public health and wellbeing. For this reason, urbanization is considered to be one the biggest threats to ecosystems, leading to native biodiversity simplification and, thus, to a detriment of the provided ecosystem services. Moreover, this change in land use results in high levels of landscape fragmentation and modification in areas surrounding the habitat remnants which, in consequence, become inadequate for many native species. In this context, it is important that urban planners have the information to assess the possible consequences of future changes in land use in order to increase the landscape chances of supporting both, native biodiversity and the needs of a growing human population. The objective of the present work is to evaluate the ecological integrity of natural and semi-natural vegetation patches immersed in an urban area in order to generate a conceptual framework for landscape assessment that allows urban planners to envision the best choice for city development at a given place. To do so, we developed a quantitative integral environmental evaluation index that includes ecological characterization, geological characterization, and environmental characterization (presence of anthropic disturbance) of the assessed area. We conclude that the index we have generated in this work is suitable to be used as a management tool to allow an unbiased valuation and to identify managing situations that require a short term response.Fil: Natale, Evangelina Sandra. Fundación Conservación y Desarrollo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Villalba, G.. Fundación Conservación y Desarrollo; ArgentinaFil: Junquera, J. E.. Fundación Conservación y Desarrollo; ArgentinaFil: Zalba, Sergio Martín. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Seed bank, germination and seed longevity of Spanish broom (Spartium junceum, Fabaceae): implications for control.

La retama (Spartium junceum) es una especie invasora de pastizales naturales en las sierras australes bonaerenses. Estudiamos características del proceso de germinación que resultarían clave para su control. Calculamos densidad de semillas y porcentaje de germinación para muestras de suelo provenientes de sectores invadidos. Realizamos ensayos de germinación en panes de tierra mantenidos a la intemperie y ensayos en cámara de germinación con semillas colectadas directamente del arbusto y otras colectadas del banco del suelo siete años antes del ensayo. La densidad en el banco del suelo de áreas invadidas varió entre 600 y 4.411 semillas/m2. El porcentaje de germinación de semillas de ensayos en panes de tierra fue de 68,33±26,66%. Para los ensayos en cámara, la escarificación mecánica resultó 100% de germinación para semillas recolectadas de las plantas, contra 7±5,7% para el control y valores aún inferiores para shock térmico y combinación shock térmico+escarificación mecánica El ensayo de semillas con más de siete años resultó en un porcentaje de germinación del 88,73±11,16% para la escarificación mecánica, 85,77±10,50% para shock térmico, 40,30±10,14% para imbibición y 43,20±12,01% para el control. Altas temperaturas durante períodos cortos, lesiones en la cubierta seminal y disturbios del suelo favorecen considerablemente la germinación y estimulan los procesos de invasión.The Spanish broom (Spartium junceum) is an exotic invader of natural grasslands in southern Buenos Aires mountains. We assessed the density of seeds in the soil seed bank and the percentage of germination in botanic garden experiments for samples obtained from three invaded sites. We performed essays outdoors for soil samples, and in germination chamber for seeds collected directly from plants and for seeds obtained from the soil seven years before the experiment. Seeds density in the soil ranged from 600 to 4411 seeds/m2. Germination percentage for soil samples was 68.33±26.66%. For chamber experiments, mechanical scarification lead to the germination of all the seeds in the case of those collected from the plants, compared to just 7±5.7% for the control and figures even smaller for heath shock and combination of heath shock and mechanical scarification. The experiment with seeds form the soil bank resulted in a percentage of germination of 88.73±11.16% for those seeds previously treated with mechanical scarification, 85.77±10.50% for heath shock, 40.30±10.14% for imbibitions and 43.20±12.01% for the control. Brief exposition to high temperatures, mechanical breakage of the seed cover and soil disturbances significatively favor germination and stimulate invasion.Fil: Sanhueza, Cristina del Carmen. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zalba, Sergio Martín. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Vector analysis: A tool for preventing the introduction of invasive alien species into protected areas

Invasive alien species are the main agent of biodiversity loss in protected natural areas. Prevention is the most appropriate management tool for addressing this challenge, however, virtually all ongoing management efforts are focused on established populations. Although invasion processes include stochastic components, it is possible to compare the different vectors of introduction that operate in a particular area in terms of their potential to transport species of high risk of invasion efficiently and, once identified, to establish strategies of prevention, early detection and rapid action. This study proposes a system of prioritization of vectors of alien plant dispersal for optimizing the efforts for preventing invasion. The system was developed for the Ernesto Tornquist Provincial Park (province of Buenos Aires, Argentina), but it is directly applicable to other areas. Natural and anthropogenic vectors were evaluated and lists of the species potentially transported by each vector were elaborated according to the characteristics of their propagules. The system analyzes the relative importance of each vector according to: 1) the severity of the potential impact of transportable species, 2) the difficulty of controlling these species, and 3) the volume of transportable propagules. In the case under study, the maximum value of risk corresponds to cargo, followed by vehicles, streams, unintentional human transport, intentional human transport, wind and finally, animals. This analysis can lead to prevention strategies, mapping of dispersal routes and actions of early detection and rapid response.Fil: Brancatelli, Gabriela Ivanna Elizabeth. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; ArgentinaFil: Zalba, Sergio Martín. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; Argentin

Seedling emergence and survival of invasive pines in Argentinian mountain grasslands

Natural regeneration is a critical step for the dispersal of alien plants and the establishment of new invasive foci. The adequate timing and location of germination, as well as the survival of the seedlings, have direct effects on the recruitment of the population, and are expected to depend on habitat characteristics. Understanding the dynamics of these processes, and their variations according to the landscape at different scales, can be particularly important to design and implement control strategies. In this article, we evaluate differences in seedling emergence and establishment of Pinus halepensis in highland grasslands of the Argentine pampas, according to altitude, orientation of the slope and vegetation cover. Our results showed spatial variation on the rate of seedling emergence, with topography as a determining factor, possibly due to a facilitating effect on the slopes with higher incident solar radiation (NE at the study site). Slope exposition, on the contrary, seemed to have the opposite effect on the survival of seedlings. Once established, seedlings also survived better in sites with less solar exposure, probably due to protection from high evapotranspiration during the summer. These results could explain variations in the invasive performance of the species and guide management actions aimed at preventing its further expansion in the study area and in other habitats with similar characteristics.Fil: Brancatelli, Gabriela Ivanna Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; ArgentinaFil: Amodeo, Martín Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; ArgentinaFil: Zalba, Sergio Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; Argentin

Caracterización de los ambientes asociados a poblaciones naturales de Pavonia cymbalaria (Malvaceae) en pastizales de Sierra de la Ventana (Buenos Aires)

El objetivo de este trabajo es contribuir al conocimiento de la biología de Pavonia cymbalaria,una especie nativa de las Sierras Australes Bonaerenses. Este conocimiento contribuirá a (1) promover su uso como especie ornamental, (2) su conservación y (3) estimular el interés y la valoración pública de la biodiversidad del sistema serrano. Se seleccionaron siete poblaciones de P. cymbalaria, dos de ellas creciendo bajo bosques de Pinus halepensis, para caracterizar distintos ambientes en donde se encuentra a la especie creciendo en forma silvestre. En cada población se estudiaron las características del ambiente inmediatamente asociado a seis ejemplares de la especie. Se midieron dieciséis parámetros ambientales, y dos índices estimativos de la cantidad y duración de los órganos florales desarrollados para este trabajo: el índice de intensidad floral y el índice de longitud del período floral. Mediante análisis de correlación pudo establecerse que las plantas ubicadas a la sombra y en el piso de los bosques presentaron en general una floración menos profusa y presentaron un follaje más deteriorado que las plantas que se encontraban a pleno sol, poniendo en evidencia el efecto negativo que ejerce, en este caso, la presencia de una especie exótica (Pinus halepensis) sobre la supervivencia y permanencia de ejemplares de P. cymbalaria.The objective of this work is to contribute to the biology of Pavonia cymbalaria A. St. Hil & Naudin (Malvaceae), a native species of the Southern mountains of Buenos Aires Province. This knowledge will contribute to (1) promote its use as an ornamental species, (2) its conservation and (3) stimulate the interest and public valuation of mountain systems biodiversity. Seven populations of P. cymbalaria were selected. Two of them were growing under Pinus halepensis forests to characterize different environments were the herbaceous species is growing in the wild. Environmental characteristics immediately associated to six individuals of the species were studied on each population. Sixteen environmental parameters and two indexes, which estimate the quantity and duration of floral organs, were measured. These indexes included those of floral intensity and length of the floral period. Correlation analyses allowed to know that plants located in the shade and forest floor flowered less intensively and presented a more deteriorated foliage than those growing in the sun. This makes evident the negative effects of P. halepensis on the survival and persistence of P. cymbalaria individuals.Fil: Torres, Y. A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Long, M. A.. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Zalba, Sergio Martín. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentin

Melanophryniscus aff. montevidensis

Distribución restringida a las Sierras y la región costera del sur de la provincia de Buenos Aires. El estatus taxonómico de estas poblaciones no ha sido esclarecido aún, pero estudios en curso indican que podrían ser poblaciones de M. montevidensis, distribuida también en Uruguay y extremo sureste de Rio Grande do Sul en Brasil (Baldo, datos no publ.)...Fil: Cairo, Samanta Lis. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; ArgentinaFil: Zalba, Sergio Martín. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; ArgentinaFil: Úbeda, Carmen A.. Universidad Nacional del Comahue. Centro Reg.universidad Bariloche. Departamento de Zoología. Cátedra de Vertebrados; Argentin

Interaction between fire and fragmentation in the successional stages of coastal dune grasslands of the southern Pampas, Argentina

Vegetation’s increased vulnerability to extrinsic disturbances is an important but less studied efect of natural habitat fragmentation. Fire is part of the evolutionary history of grassland ecosystems, but fragmentation by forest plantations can alter the fre regime and infuence their resilience. This study compares the successional trajectories after fre in continuous and fragmented grassland in terms of composition and abundance of plant species. Grassland fragments of varying sizes (0.1 to 2.5ha) surrounded by a forest matrix and grassland controls of an equivalent area in adjacent, non-fragmented sites were selected. Fire was associated with an increase in the abundance of exotic plants in the fragmented grassland whereas the continuous grasslands were much more resistant to invasion. These diferences in the species composition between fragments and continuous areas, which were limited to the smaller areas before the fre, were observed one year after the fre throughout the range of sizes analyzed. These results show the impact of fragmentation on grassland resilience and how the efects of this process become evident even months after a disturbance, highlighting the synergistic efect of habitat fragmentation and biological invasions, two factors identifed as the main forces of biodiversity erosion.Fil: Yezzi, Alejandra Lorena. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Nebbia, Ana Julia. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Zalba, Sergio Martín. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentin

Mapping risk: Priorities to prevent the establishment of invasive Salt Cedar (Tamarix spp.)

Early detection and rapid intervention are among the preferred actions to achieve successful results in the management plans for invasive alien species. The identification of areas where probabilities of establishment and invasion by an alien species are high can reduce logistic and economic costs. Risk assessment based on information about the alien species and the invaded environment has become a widely-accepted tool to estimate the likelihood and magnitude of the threat. The objective of this work was to develop an invasion risk index that can be modeled within a geographic information system (GIS) environment, combining information on the current and potential distribution of the alien species, the analysis of dispersion routes and the potential impact on environmental and socioeconomic values. The genus Tamarix was used as a case study. This genus is widely distributed in Argentina, from northern Patagonia to the northwest of the country. A risk index was obtained, with potential to be expressed cartographically in a GIS. The relevance of the developed index is that it might be extended and applied to different invasive species, regions and working scales.Fil: Natale, Evangelina Sandra. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Instituto de Ciencias de la Tierra, Biodiversidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Cordoba. Instituto de Ciencias de la Tierra, Biodiversidad y Ambiente.; ArgentinaFil: Reinoso, Herminda Elmira. Universidad Nacional de Río Cuarto; ArgentinaFil: Zalba, Sergio Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Sur; Argentin