Ruderales exóticas versus ruderales nativas : respuesta a disturbios, retroalimentaciones planta - suelo y rasgos de historia de vida

Avances teóricos recientes en la actual teoría de coexistencia sugieren que el establecimiento de exóticas en la comunidad local ocurre a través de diferencias de nicho o a través de diferencias que favorecen el desempeño pero que la exclusión competitiva solo se logra a través de las diferencias en desempeño.. Esta tesis explora ambos tipos de diferencias para ganar conocimiento respecto a los procesos que controlan rrelaciones de coexistencia y exclusión de exóticas y nativas en comunidades ruderales del bosque de caldén (Prosopis caldenia) en Argentina.. Específicamente, en esta tesis se evaluó: 1) la respuesta de ruderales exóticas y nativas a distintos tipos de disturbio, 2) la importancia de las retroalimentaciones planta - suelo y efectos competitivos en exóticas y nativas, 3) rasgos de historia de vida de ruderales en un sistema rico en especies ruderales de ambos orígenes.. Para esto se realizaron muestreos de vegetación en sitios que evidenciaran la ocurrencia de distintos tipos de disturbio (mantenimiento de picada y banquinas, pastoreo y fuego) y experimentos de invernáculo para evaluar a. retroalimentaciones planta - suelo y efectos competitivos en ruderales exóticas y nativas y b. rasgos de historia de vida de estos grupos.. El origen de las especies que dominan en la comunidad ruderal depende del tipo de disturbio : en paticular, las exóticas sólo dominaron en ambientes sujetos al mantenimiento de picadas y banquina y nativas en fuego.. Las retroalimentaciones planta - suelo, efectos competitivos y rasgos de historia de vida aquí evaluados fueron similares para exóticas y nativas.. En conjunto, los resultados de esta tesis muestran que ruderales exóticas y ruderales nativas coexisten en el bosque de caldén, ayudan a explicar esa coexistencia y resaltan la importancia del tipo de disturbio en el éxito de las exóticas

The interplay between propagule pressure, seed predation and ectomycorrhizal fungi in plant invasion

There are many hypotheses aiming to explain invasion success, but evaluating individual hypotheses in isolation may hinder our ability to understand why some species invade and others fail. Here we evaluate the interaction between propagule pressure, seed predation and missed mutualism in the invasion success of the pine, Pinus ponderosa. We evaluated the independent and interactive effects of propagule pressure and seed predation at increasing distances from a pine plantation. Additionally, because pines are obligate mutualists with ectomycorrhizal fungi (EMF) and pine invasions fail in the absence of their EMF symbionts, we evaluated EMF availability through a growth chamber bioassay. In this bioassay we measured root colonization by EMF with soil samples collected from the different distances from the plantation. We found that propagule pressure overwhelms seed predation only at the edge of the pine plantation, while seed predation overcomes propagule pressure at 25 m and further distances from the plantation. We also found that EMF root colonization decreases with distance from the plantation. However, pine roots were colonized up to 200 m from the plantation, suggesting that EMF may not be hindering invasion, at least not on the scale of this experiment. Taken together our results demonstrate that seed predation may be limiting the invasion of P. ponderosa in the study region as propagule pressure only overcomes seed predation at the plantation edge. Here we provide evidence of how strong biotic resistance can suppress an invasion, regardless of the variation in propagule pressure and the availability of mutualists.Fil: Moyano, Jaime. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Chiuffo, Mariana Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Policelli, Nahuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Nuñez, Martin Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Rodriguez Cabal, Mariano Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

Globally, plant-soil feedbacks are weak predictors of plant abundance

Plant-soil feedbacks (PSFs) have been shown to strongly affect plant performance under controlled conditions, and PSFs are thought to have far reaching consequences for plant population dynamics and the structuring of plant communities. However, thus far the relationship between PSF and plant species abundance in the field is not consistent. Here, we synthesize PSF experiments from tropical forests to semiarid grasslands, and test for a positive relationship between plant abundance in the field and PSFs estimated from controlled bioassays. We meta-analyzed results from 22 PSF experiments and found an overall positive correlation (0.12 <= r over bar <= 0.32) between plant abundance in the field and PSFs across plant functional types (herbaceous and woody plants) but also variation by plant functional type. Thus, our analysis provides quantitative support that plant abundance has a general albeit weak positive relationship with PSFs across ecosystems. Overall, our results suggest that harmful soil biota tend to accumulate around and disproportionately impact species that are rare. However, data for the herbaceous species, which are most common in the literature, had no significant abundance-PSFs relationship. Therefore, we conclude that further work is needed within and across biomes, succession stages and plant types, both under controlled and field conditions, while separating PSF effects from other drivers (e.g., herbivory, competition, disturbance) of plant abundance to tease apart the role of soil biota in causing patterns of plant rarity versus commonness

Centaurea solstitialis L.

El objetivo de este Manual es ayudar a la identificación de las especies de plantas invasoras más comunes en nuestro continente. En términos generales, incluye 43 especies que ocupan regiones tropicales y templadas de nuestro continente. El libro está estructurado en base en fichas que resumen de manera simple los aspectos más básicos para la identificación de las especies y su historia natural. Cada ficha muestra una descripción de los caracteres diagnósticos y ecológicos de la especie, fotografías de cada especie, y se enfatiza en cada caso los impactos y los procedimientos que se han usado para su manejo y controlFil: Chiuffo, Mariana Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

Salsola kali L.

El objetivo de este Manual es ayudar a la identificación de las especies de plantas invasoras más comunes en nuestro continente. En términos generales, este Manual incluye 43 especies que ocupan regiones tropicales y templadas de nuestro continente. El libro está estructurado en base en fchas que resumen de manera simple los aspectos más básicos para la identificación de las especies y su historia natural. Cada ficha muestra una descripción de los caracteres diagnósticos y ecológicos de la especie, fotografías de cada especie, y se enfatiza en cada caso los impactos y los procedimientos que se han usado para su manejo y control.Fil: Chiuffo, Mariana Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

The legacy of pine introduction threatens the fuel traits of Patagonian native forests

The introduction of non-native pine plantations and subsequent pine invasion are increasingly affecting native and high conservation value forests in the Southern Hemisphere. Pine invasion changes forest fire regimes, even in protected areas. However, most research evaluating the impact on fuel of this invasion on South American habitats has focused on steppe ecosystems; few studies have investigated whether pine-dominated areas are more flammable than native forests, how invasion age influences flammability, and whether areas dominated by mature pines from invasion and plantation have a similar impact on fuel. Here, we analyzed the fine fuel traits of the understory of different-aged post-fire invasions, plantations of Pinus radiata, and nearby native vegetation in a forest reserve (Patagonia, Argentina). Community composition shifts towards pine-dominated areas increased fire risk by affecting the quantity, distribution, composition, and condition (live or dead) of the fuel. Flammability levels increased with time since invasion. The oldest invasion had a higher load of the most flammable fuel than the adult plantation. Our results show that community composition shifts towards pine-dominated areas can increase fire risk by producing more pyrophytic habitats, and suggest that early removal of post-fire invasions can prevent increased fire risk on a landscape scale. Our results highlight the importance of considering the intrinsic characteristics of an invasion context when evaluating the impact of non-native species, and the need to be cautious when extrapolating the impacts of plantations to invasions.Fil: Franzese, Jorgelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Raffaele, Estela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Chiuffo, Mariana Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Blackhall, Melisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

Native and non-native ruderals experience similar plant: soil feedbacks and neighbor effects in a system where they coexist

Recent applications of coexistence theory to plant invasions posit that non-natives establish in resident communities through either niche differences or traits conferring them with fitness advantages, the former being associated with coexistence and the latter with dominance and competitive exclusion. Plant–soil feedback is a mechanism that is known to explain both coexistence and dominance. In a system where natives and non-natives appear to coexist, we explored how plant–soil feedbacks affect the performance of nine native and nine non-native ruderal species—the prevalent life-history strategy among non-natives—when grown alone and with a phytometer. We also conducted field samplings to estimate the abundance of the 18 species, and related feedbacks to abundances. We found that groups of native and non-native ruderals displayed similar frequencies of negative, positive, and neutral feedbacks, resulting in no detectable differences between natives and non-natives. Likewise, the phytometer exerted comparable negative impacts on native and non-native plants, which were unchanged by plant–soil feedbacks. Finally, feedbacks explained plant abundances only after removing one influential species which exhibited strong positive feedbacks but low abundance. Importantly, however, four out of five species with negative feedbacks were rare in the field. These findings suggest that soil feedbacks and plant–plant interactions do not confer an advantage to non-native over native species, but do contribute to the observed coexistence of these groups in the system. By comparing natives and non-natives with overlapping abundances and strategies, our work broadens understanding of the consequences of plant–soil feedbacks in plant invasion and, more generally, coexistence within plant communities.Fil: Chiuffo, Mariana Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; ArgentinaFil: MacDougall, Andrew S.. University of Guelph; CanadáFil: Hierro, Jose Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; Argentin

Non-native conditions favor non-native populations of invasive plant: demographic consequences of seed size variation?

Trait differences between native and non-native populations may explain the greater abundance and impact of some organisms in their non-native ranges than in their native ranges. Here, we conducted reciprocal common gardens in southwestern Turkey (home) and central Argentina (away) to explore the hypothesis that the greater success of the invasive ruderal Centaurea solstitialis in Argentina than Turkey is partially explained by differences between home and away populations. Unusual among common gardens, our experimental design included seed additions to explicitly evaluate population level responses, as well as disturbance and no-disturbance treatments. We documented seed mass in native and non-native populations, and during the experiment, we periodically measured density, plant size, and herbivory. After six months, we determined the establishment of plants for populations from both origins in both home and away common gardens. Seed mass was two times larger for Argentinean than Turkish populations. Density, plant size and final establishment were also greater for plants from Argentinean than from Turkish populations, but only in the common garden in Argentina. In Turkey, no differences between population origins were detected for these variables. Herbivory was similar for populations from both origins in both common gardens. As expected, disturbance generally increased plant performance in both regions. Our results suggest that increased seed size in non-native populations may have demographic consequences under non-native conditions that can contribute to the invasive success of C. solstitialis. This is the first reciprocal common garden that supports the idea that seed size variation contributes to demographic differences for an invasive species between native and non-native distributions, but our findings further suggest that seed size effects on demography depend on the ecological context in which population processes occur.Fil: Hierro, Jose Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de la Pampa. Universidad Nacional de la Pampa. Facultad de Cs.exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de la Pampa; ArgentinaFil: Eren, Özkan. Adnan Menderes Universitesi; TurquíaFil: Villarreal, Diego. Universidad Nacional de La Pampa; ArgentinaFil: Chiuffo, Mariana Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de la Pampa. Universidad Nacional de la Pampa. Facultad de Cs.exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de la Pampa; Argentin

Rodent seed predation as a biotic filter influencing exotic plant abundance and distribution

Biotic resistance is commonly invoked to explain why many exotic plants fail to thrive in introduced ranges, but the role of seed predation as an invasion filter is understudied. Abiotic conditions may also influence plant populations and can interact with consumers to determine plant distributions, but how these factors jointly influence invasions is poorly understood. In central Argentina’s Caldenal savannas, we experimentally examined how seed predation and water availability influenced recruitment/establishment of nine exotic plant invaders over 2 years. We then explored how seed predation patterns related to invasion patterns. Excluding rodent seed predators dramatically increased seedling recruitment for eight of nine exotic species (by 100–300 % in most cases) and increased young/adult plant abundance for four species in one or both years. Adding water to ameliorate drought tended to increase seedling numbers for most species, but these trends were not significant. Vegetation surveys revealed that exotic plant richness was 50 % lower in matrix habitat compared with disturbed roadsides and that cover of the two most aggressive invaders, which were both strongly suppressed by seed predation, was 75–80 % lower in matrix than roadside habitats. Seed offerings indicated seed removal by rodents was 11 times greater in intact matrix habitat compared with roadsides. Rodent seed predation represents a significant source of biotic resistance to plant invasions. Ubiquitous disturbances such as road construction can disrupt this filter. The widely recognized role that disturbance plays in facilitating invasions, which is largely attributed solely to reduced plant competition, may also arise from disruption of top–down controls.Fil: Pearson, D.E.. University of Montana; Estados Unidos. United States Department of Agriculture; Estados UnidosFil: Hierro, Jose Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Chiuffo, Mariana Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; ArgentinaFil: Villarreal, D.. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; Argentin