Carlos E. Valdivia

Do floral syndromes predict specialisation in plant pollination systems? Assessment of diurnal and nocturnal pollination of Escallonia myrtoidea

Abstract Pollination syndromes lead to questions concerning the role of different suites of pollinators on the pollination success of plants. Escallonia myrtoidea exhibits floral traits associated with pollination by diurnal butterflies; however, flowers remain open during the night and, thus, may also be pollinated by nocturnal moths. We assessed frequency of pollinator visits and pollination success in flowers exposed to diurnal and nocturnal pollinators in a factorial design. We also assessed pollinator dependency and limitations for seed set through hand self‐ and hand cross‐pollination tests. Flowers were visited mainly by bees rather than by butterflies or moths. Neither diurnal nor nocturnal pollinators had any effect on seed set over the seed set of always‐bagged inflorescences, while hand cross‐pollinated flowers produced significantly more seeds than hand self‐pollinated flowers or flowers exposed to diurnal and/or nocturnal pollinators. Thus, E. myrtoidea, a tree strongly pollinator‐limited for seed setting, exhibited a lack of coupling among floral traits, pollinators, and reproductive success.

SISTEMA REPRODUCTIVO EN CRINODENDRON PATAGUA MOL. (ELAEOCARPACEAE), UN ARBOL ENDEMICO DE CHILE CENTRAL

Se determino el sistema reproductivo del arbol endemico de Chile central Crinodendron patagua, realizandose cuatro tratamientos de polinizacion dirigida mas un control por polinizacion natural. Las flores de la prueba de agamospermia no fructificaron exitosamente, demostrando que la especie no es apomictica. La prueba de autopolinizacion automatica alcanzo un 6,9% de fructificacion, a pesar del 27,7% de fructificacion alcanzado en la prueba de autopolinizacion manual. La prueba de polinizacion cruzada alcanzo un 72,9% de fructificacion exitosa, igualando el valor de fructificacion en la prueba de polinizacion natural. De acuerdo a estos datos, C. patagua debe ser considerada como una planta autoincompatible, con un indice de incompatibilidad de 0,12, ademas de xenogama. De hecho, C. patagua presenta una floracion masiva en primavera, dando numerosas flores blancas con forma de campana que son visitadas por himenopteros y dipteros que pueden actuar como vectores polinicos

Phenological synchrony between the austral thrush Turdus falcklandii (Passeriformes: Turdidae) and its food resources within forests and prairies in southern Chile

BackgroundFrugivorous birds are phenologically linked to the fruits that they eat. When there is less fruit in seasonal environments, frugivorous birds complement their diet by eating invertebrates. The depth of the phenological link between frugivorous birds and their dietary resources has not been studied until now. The objective was to determine the possible phenological synchrony between the Austral thrush (Turdus falcklandii) and its dietary resource, fruits and annelids, found in the fragmented forests in the South of Chile.ResultsThe numbers of thrushes, annelids, and fruits in fragments of native forest and anthropogenic grassland in Chiles Lake District were estimated annually. Spatial variation (i.e., forest and grassland) and seasonal variation (i.e., the period of greatest fruit growth and least fruit growth) on thrushes, annelids, and fruits were analyzed with a nonparametric Scheirer-Ray-Hare extension for the Kruskal-Wallis test. The graphic representation of the seasonal variation of thrushes, annelids, and fruits was carried out using cubic spline routines. It was found that there are seasonal changes in the dietary resources of these birds. During the period of greatest fruit production, there was a trend towards a higher number of thrushes in the forest where there was a greater availability of ripe fruit in relation to the nearby grasslands. In the grasslands, the annelids demonstrated a trend towards greater quantities in comparison with the forest. There was a positive and significant correlation between the thrushes and the annelids and fruits, indicating phenological synchrony between this bird and its dietary resources.ConclusionsTherefore, we concluded that the thrush responded numerically and functionally to the variations in its resources. The result of our research underlines the importance of grasslands in maintaining thrush populations, with this bird acting as one of the most important seed dispersers in the temperate southern forests of Chile.

EN LA SENDA DE LA EXTINCIÓN: EL CASO DEL ALGARROBO PROSOPIS CHILENSIS (FABACEAE) Y EL BOSQUE ESPINOSO EN LA REGIÓN METROPOLITANA DE CHILE CENTRAL

En la zona central de Chile se encuentra el bosque espinoso de Acacia caven y Prosopis chilensis, donde persiste menos del 40% de su superficie original, aunque sin representacion en las areas silvestres protegidas. Debido a la accion del ganado, se ha sugerido una contraccion poblacional de P. chilensis acoplado a una expansion poblacional de A. caven lo cual, sin embargo, no ha sido verificado empiricamente. En cuatro sitios correspondientes a dos microcuencas de la Region Metropolitana en Chile (Batuco y Huechun), se evaluo la incidencia de las perturbaciones ambientales (ganado, conejos, malezas, basuras), el estado fitosanitario y estructura poblacional de P. chilensis, asi como las dinamicas de regeneracion de este arbol y A. caven, mediante el uso de matrices de transiciones Markovianas. Las poblaciones de P. chilensis enfrentan similares grados de amenaza, exhiben un estado fitosanitario similar y deficitario y, consecuentemente, se encuentran en estado senescente prontas a desaparecer una vez muertos los individuos adultos de las siguientes dos generaciones. Ademas, la contraccion poblacional de P. chilensis no se correlaciona con una expansion poblacional de A. caven, por lo cual las dos especies que definen y caracterizan el bosque espinoso de la Region Metropolitana de Chile se encuentran prontas a extinguirse y con ellas el piso vegetacional. Surge, por lo tanto, como necesidad urgente el establecer las medidas de conservacion y restauracion necesarias para asegurar la persistencia del bosque espinoso en la Region Metropolitana de Chile.

Reproductive biology aspects of two species of the genus Gavilea (Orchidaceae, Chloraeinae) in populations from Central Chile

El alcance al cual las plantas dependen de polinizadores para el transporte de polen para los exocruzamientos es uno de los temas claves en ecologia reproductiva de las plantas. Evaluamos el sistema reproductivo potencial, despliegue foral y polinizacion natural en dos orquideas del Cono Sur de Sudamerica, Gavilea araucana y G. venosa, efectuando cuatro ensayos de polinizacion manual (agamospermia, autogamia, geitonogamia y xenogamia) y contando cada for y fruto producidos por las plantas en condiciones naturales. La produccion de frutos difrio signifcativamente dependiendo del origen del polen asi como de la presencia de un vector polinico. Ninguna de las especies produjo frutos en las pruebas de agamospermia indicando, por lo tanto, que ellas requieren de la presencia de polen en los estigmas para producir frutos. Por el contrario, solamente G. araucana fue capaz de producir frutos siguiendo la prueba de autogamia demostrando, por ende, que esta orquidea no necesita depender de polinizadores para producir frutos. Ademas, G. araucana y G. venosa produjeron un 100% de frutos por geitonogamia y xenogamia, indicando esto, que ambas plantas son autocompatibles. El numero promedio de fores por planta fue 2,1 veces mayor en G. venosa con respecto a G. araucana; sin embargo, el exito en la fructifcacion natural fue de 28,8% y 98,9%, respectivamente. Ademas, mientras el incremento en el exito de la fructifcacion se correlaciono positiva y signifcativamente en G. araucana, en G. venosa estas variables no estuvieron relacionadas. Ciertamente, estudios adicionales referidos a las estrategias reproductivas de las orquideas del sur de Sudamerica son de gran importancia.

Use of tree species by White-throated treerunner (Pygarrhichas albogularis King) in a secondary native forest of southern Chile

In forest ecosystems, numerous species of insectivorous birds use certain tree species as feeding and nesting substrates. Between 2009 and 2010, the use of different floristic components as feeding substrate by the Pygarrhichas albogularis King, 1831 was evaluated in a southern Chilean secondary native forest. From a total of 13 trees and bush species, six tree species were used by P. albogularis as a feeding substrate. Tree use was limited to intermediate heights (11-20 m) and, mainly, to the trunk (40% of observations) and secondary branches (26%). Pygarrhichas albogularis showed a disproportionated use of N. dombeyi and an important use of trees with a greater age structure (DBH 81-100 cm). Nothofagus dombeyi presented a significantly greater tree bark crevice depth than E. cordifolia. In turn, covariance between crevice depth and invertebrate supply in tree bark was positive and significant. We consider bark depth and invertebrate supply to be the proximate causes explaining P. albogularis disproportionated use of Nothofagus dombeyi.

Bird-mediated effect of deforestation on potential seed dispersal does not increase the seed recruitment of Fuchsia magellanica

Key messageThis work contributes to clarify the effects of small-scaled deforestation and key traits of plants and animals on frugivory, seed dispersal and seedling recruitment of a shade-intolerant plant.AbstractHabitat destruction usually reduces the frugivory and seed dispersal by animals. This negative effect could be counterbalanced by seedling recruitment in shade-intolerant plants. We tested this assumption using the shrub Fuchsia magellanica as a model. We estimated the deforestation as the percentage of ground surface devoid of native forest at small and large scales around 20 plants per population and 12 populations. This procedure was performed to evaluate the effects of deforestation, at both spatial scales, on fruit traits, frugivory, seed dispersal, and seedling recruitment. Fruit traits (size, shape, color, sugar concentration, and number of seeds) were measured in each plant. Frugivory by lizards and birds were recorded as the percentage of fruit consumed, using ten artificial play dough fruits per plant. Putative seed dispersal was estimated as the product of the number of play dough fruits attacked and mean number of seeds per fruit. Seedling recruitment was evaluated as the density of seedlings growing around adult plants. The fruit traits of F. magellanica varied among populations in size, shape, color, sugar concentration and number of seeds. Only color correlated with deforestation at a large scale, the fruits being more reddish-brown in deforested populations. This variation, however, did not affect frugivory. The number of play dough fruits attacked by birds exhibited a tendency to be positively affected by deforestation at a large scale, which could be translated into a positive effect of deforestation on potential seed dispersal. Nevertheless, there was not an increase in seedlings recruitment. Consequently, the deforestation did not increase the seedling recruitment of this pioneer species.

The endosperm of a rare tree endemic to Chile, Gomortega keule, has two parts with different chemical composition

ABSTRACT ‘Queule’ (Gomortega keule) is an endemic and endangered Chilean tree belonging to the monotypic family Gomortegaceae. Inside its edible fruit the usually single seed has an oily endosperm divided in two distinctive parts; this represents a unique organisation of storage tissue in angiosperm seeds. Since this trait has not been previously reported in literature, this study aimed to describe both parts of the storage tissue and to identify the presence of lipid, starch and protein. Seeds were observed using the paraffin method and handmade slices. Specific dyes were applied to identify chemical compounds. Oil content was quantified in both parts of the endosperm. Additionally, seed and embryo size were measured from endocarps collected from the forest floor during an 8 month period. Increased embryo size and absence of germination suggest morphological dormancy. Histological slices showed abundant and larger starch grains in the inner part of the endosperm, and lower presence of proteins compared to the outer part. In terms of oil content, the inner part of the endosperm contained 27% (w/w fresh weight), the embryo 22% and the outer part 20%. Although both parts of the storage tissue are notoriously different, both belong to the endosperm. The presence of oil, proteins and starch in the storage tissue may provide ecological advantages for seedling establishment.

Ant-Mediated Nectar Robbing from the Chilean Firetree Embothrium coccineum (Proteaceae): No Effect on Seed Production

Nectar robbing by the ant Camponotus distinguendus was observed in flowers of Embothrium coccineum (Proteaceae), a tree mainly pollinated by hummingbirds. We hypothesized that robbing would reduce the amount of nectar, affecting the foraging behaviour of floral visitors and reducing seed production. Nectar robbing affected one-third of mature tree blossoms and 93.3% of trees. This reduced the amount of nectar to about half. Foraging behaviour of floral visitors included pollinating visits to consume nectar and pollen, primary and secondary nectar robbing, and nectar theft. We found no effect of nectar robbing by C. distinguendus on seed production in E. coccineum, which was sparse and completely dependent on legitimate pollinator visits, mostly performed by the green-backed firecrown Sephanoides sephaniodes. Determining the effects of nectar robbing by ants on the reproduction of plants is important to understand the dynamics of plant-animal interactions in the temperate forests of Chile.

La frugivoría por cánidos nativos (Lycalopex spp.) y alóctonos (Canis lupus familiaris) reduce la germinación de semillas de litre (Lithrea caustica) en Chile central

El consumo de semillas por animales podria incrementar la probabilidad de germinacion al pasar por el tracto digestivo animal. La perdida de un dispersor nativo por causas de origen humano podria compensarse por dispersores generalistas introducidos. El objetivo de este trabajo fue evaluar el papel de los perros y zorros en la germinacion y viabilidad de semillas de Lithrea caustica. Se comparo la eficacia de zorros y perros como dispersores de L. caustica mediante la germinacion y viabilidad post-germinativa de semillas provenientes de heces, mas un control dado por semillas colectadas directamente desde los arboles. Se consideraron 11 replicas por tratamiento y 20 semillas por replica. El experimento duro 18 semanas con un suministro de agua ad libitum (termoperiodo: 25,7 ± 0,1 °C y 12,7 ± 0,2 °C, y fotoperiodo: 12 h luz y 12 h oscuridad). La maxima germinacion ocurrio el dia 126. El porcentaje de germinacion de semillas consumida por perros (24,5 %) no difirio significativamente del porcentaje de germinacion de semillas consumidas por zorros (28,2 %), y ambos fueron significativamente menores que el control (45,5 %). La viabilidad de las semillas post germinacion no difirio significativamente segun el tipo de consumidor, aunque hubo una tendencia a que las semillas consumidas por perros fuesen menos viables (40,5 %) que las consumidas por zorros (80,7 %). Consecuentemente, los perros eventualmente pueden suplir el rol de los zorros pese a que ambos parecen ser mutualistas ineficientes de L. caustica al disminuir su capacidad germinativa, aunque no su viabilidad post germinacion.