Gloria Montenegro

Landscape disturbance and biodiversity in mediterranean-type ecosystems.

1 Landscape Disturbance in Mediterranean-Type Ecosystems: An Overview.- 2 From Biodiversity to Ecodiversity - Holistic Conservation of the Biological and Cultural Diversity of Mediterranean Landscapes.- 3 Ecological Indicators of Landscape Degradation.- 4 Land Use Conflicts in the Western Cape Region of South Africa.- 5 Impacts of Land Use on Biodiversity in Southwestern Australia.- 6 Land Use Conflicts in California.- 7 Abandoned Lands and Land Use Conflicts in Southern France.- 8 Land Use Changes and Conflicts in the Mediterranean-Type Ecosystems of Western Crete.- 9 Land Use Changes and Conflicts in Central Chile.- 10 Local Endemism and Plant Conservation in the Cape Floristic Region.- 11 Managing Biodiversity on the Cape Peninsula, South Africa: A Hotspot Under Pressure.- 12 Biodiversity and Conservation Biology of Coastal Transition Zones from Mediterranean to Desert Ecosystems: An Intercontinental Comparison.- 13 Distribution and Ecology of Geophytes in Chile. Conservation Threats to Geophytes in Mediterranean-Type Regions.- 14 Coupling Demography, Physiology and Evolution in Chaparral Shrubs.- 15 Physiological Ecology of Mediterranean Seeds: Links with Ex Situ Conservation of Plants.- 16 Aspects of Demography in Post-Fire Mediterranean Plant Communities of Greece.- 17 Ecophysiological Processes and Demographic Patterns in the Structuring of California Chaparral.- 18 Insect Population Changes and Conservation in the Disturbed Landscapes of Mediterranean-Type Ecosystems.- 19 Loss of Vertebrate Diversity Following European Settlement of Australian Mediterranean Regions.- 20 Bird Diversity in a Changing Landscape (Tuscany, Italy).- 21 Patterns of Mammalian Biodiversity, Urbanization, and Land Use in Southern California.- 22 Biodiversity in Fluctuating Dry-Land Environments: Basic and Applied Aspects.- 23 Politics and Environment in Mediterranean-Climate Regions.- Species Index.

Biomass, Phenology, and Growth

In this chapter, shrub structure, biomass, phenology, and growth at Echo Valley and Fundo Santa Laura are analyzed and compared. The growth dynamics of shoot and root systems are studied and the similarity of these growth processes in both countries assessed.

Fire regimes and vegetation responses in two Mediterranean-climate regions

Los incendios forestales originados por tormentas estivales son una caracteristica comun en la mayoria de las regiones con clima Mediterraneo, tal como el sur de California, y han jugado un rol importante en la ecologia y evolucion de su flora. Las regiones con clima Mediterraneo han sido, ademas, centros importantes para el establecimiento de poblaciones humanas, las que al alterar los regimenes de incendios podrian producir efectos negativos importantes en este tipo de formaciones vegetales. Sin embargo, los efectos antropicos sobre el regimen de incendios podrian tener impactos distintos en ecosistemas Mediterraneos cuya vegetacion ha evolucionado naturalmente con este tipo de perturbacion. Asi, en este trabajo comparamos los regimenes de incendios y la capacidad de respuesta de la vegetacion de dos regiones con clima Mediterraneo que han tenido historias distintas en cuanto a la ocurrencia natural de incendios forestales y de ocupacion humana, tales como la zona central de Chile (matorral) y el sur de California (chaparral). En Chile, casi todos los incendios forestales son el resultado de actividades antropicas, mientras que en California los incendios producidos por el hombre se suman a los producidos por tormentas estivales. En ambas regiones, los incendios son mas frecuentes en verano debido a la acumulacion de biomasa vegetal seca altamente combustible. El hombre ha incrementado significativamente la frecuencia de incendios tanto en el matorral como en el chaparral en las ultimas decadas, pero la extension de los incendios no se ha incrementado en forma importante, probablemente debido a mejores sistemas de supresion del fuego y a la menor acumulacion de biomasa vegetal seca por el aumento de la fragmentacion del paisaje con desarrollos urbanos y agricolas con menor potencial de combustion. Como se esperaba, las respuestas de regeneracion de las plantas despues de los incendios son distintas en el matorral y en el chaparral. Las plantas del matorral muestran un rango de respuestas regenerativas mayor, las que van desde el rebrote basal, al rebrote desde el lignotuber y a la germinacion y floracion estimuladas por el fuego, con estimulos fuego-especificos tales como shock termico, quimicos presentes en el humo y en la madera quemada. Las plantas del matorral tienen cierta capacidad de regeneracion despues del fuego, pero estas probablemente evolucionaron como consecuencia de otras presiones ambientales, tales como las severas y largas sequias de verano, la herbivoria y el volcanismo. Aunque ambos ecosistemas de tipo Mediterraneo han mostrado ser resistentes a los incendios de origen antropico, el marcado aumento en la frecuencia de estos puede constituir un aspecto muy importante de considerar, ya que puede resultar en efectos negativos importantes tanto en los patrones sucesionales como en la diversidad vegetal

Growth Dynamics of Chilean Matorral Shrubs

Seasonal patterns of leaf area increment and shoot elongation of six Chilean matorral shrub species were analyzed. The leaf area of individual shoots was measured weekly. The leaf area growth rates during the flushing period varied from 0.6 cm2/wk for Satureja gilliesii to 28.9 cm2/wk for Lithraea caustica. The six species had characteristic temporal growth patterns. Satureja gilliesii initiated growth shortly after the first winter rains in June while L. caustica, the last species to become vegetatively active, showed first leaf growth in November (late spring). Shoot elongation rates ranged from 0.06 cm/day for Colliguaya odorifera to 0.17 cm/day for the two summer-deciduous species, S. gilliesii and Trevoa trinervis. The species with low growth rates have long growth periods, and species with high growth rates have short but intensive flushing periods.

Antitubercular activity of pentacyclic triterpenoids from plants of Argentina and Chile.

Screening of plants from South America for antitubercular activity and subsequent assay-guided fractionation resulted in the isolation and characterization of several pentacyclic triterpenoids. The MIC values of 22 triterpenoids were determined using the radiorespiratory BACTEC assay and range from 8 microM to above 128 microM. The structure-activity relationships are discussed.

Anthocyanin profiling of wild maqui berries (Aristotelia chilensis [Mol.] Stuntz) from different geographical regions in Chile

BACKGROUND Maqui (Aristotelia chilensis) is a Chilean species which produces small berries that are collected from the wild. Anthocyanins, because of their health benefits, are the major focus of interest in maqui fruit. For this study, we examined anthocyanin and phenolic content of maqui fruits from individuals that belonged to four geographical areas in Chile, and used DNA marker analysis to examine the genetic variability of maqui populations that had distinctly different fruit anthocyanin content. RESULTS Twelve primers generated a total of 145 polymorphic inter simple sequence repeat-polymerase chain reaction (ISSR-PCR) bands. ISSR-PCR showed different banding patterns for the individuals evaluated, confirming that maqui populations belonged to different genotypes. Maqui fruit from four different geographical regions during two consecutive growing seasons showed high total anthocyanin (6.6-15.0 g cy-3-glu kg⁻¹ fresh weight (FW)) and phenolic (10.7-20.5 g GAE kg⁻¹ FW) contents and different anthocyanin profiles. CONCLUSION Three maqui genotypes exhibited significantly higher anthocyanin content than the others, as measured by pH differential method and high-performance liquid chromatography-mass spectrometry. Significant genetic diversity was noted within each ecological population. ISSR-PCR analysis provided a fingerprinting approach applicable for differentiation of maqui genotypes.

The antifungal effect of six commercial extracts of Chilean propolis on Candida spp

Propolis has been used in traditional medicine for many centuries because of its beneficial health properties, including its antimicrobial capacity. Prosthesis stomatitis affects a significant percentage of users of removable dentures; Candida albicans is the most common fungal species associated with the development of this pathology. Thus, the objectives of this study were: a. To evaluate the antifungal activity of six commercial propolis extracts against Candida spp. that was isolated from the oral cavity of removable dentures users, and b. To determine chemical characteristics of the propolis extracts evaluated. Among the results, we note that these concentrations of polyphenols varied between 9 ± 0.3 and 85 ± 2.1 mg mL-1. Chromatographic analysis was able to detect 35 compounds, among which were caffeic acid, myricetin, quercetin, kaempferol, apigenin, pinocembrin, galangin, and caffeic acid phenyl ester (CAPE). All strains tested were inhibited by the liquid extracts of propolis. The MID ranged between 1:40 and 1:1280, and the MIC for C. albicans ranged from 197 µg mL-1 to 441 µg mL-1. From the results obtained in this investigation, we can conclude that all propolis extracts evaluated are capable of inhibiting the development of Candida spp. However, they show significant differences in the concentration of polyphenols present and in antifungal activity. El propoleo ha sido utilizado por la medicina tradicional desde hace muchos siglos debido a sus propiedades beneficas para la salud, entre las que destaca su capacidad antimicrobiana. La estomatitis subprotesica, afecta a un porcentaje importante de usuarios de protesis dental removible, siendo Candida albicans la especie fungica mas comun asociada al desarrollo de esta patologia. Asi, los objetivos de este estudio fueron: a) evaluar la actividad antifungica de seis extractos de propoleos comerciales sobre cepas de Candida spp. aisladas de la cavidad oral de usuarios de protesis dental removible, y b) determinar algunas caracteristicas quimicas de los extractos de propoleos utilizados. Entre los resultados obtenidos, podemos senalar que estos mostraron concentraciones de polifenoles que variaron entre 9 ± 0,3 y 85 ± 2,1 mg/mL. El analisis cromatografico permitio detectar 35 compuestos, entre los cuales se logro identificar la presencia de acido cafeico, miricetina, quercetina, kaempferol, apigenina, pinocembrina, galangina y acido cafeico fenil ester (CAPE). Todas las cepas de Candida spp. evaluadas fueron inhibidas por los seis extractos liquidos de propoleos, observandose que la DIM vario entre 1/40 y 1/1280, y la CIM para C. albicans vario entre 197 µg/mL y 441 µg/mL. A partir de los resultados obtenidos en esta investigacion podemos concluir que todos los propoleos evaluados son capaces de inhibir el desarrollo de Candida spp. , sin embargo, estos muestran importantes diferencias en la concentracion de los polifenoles presentes y en la actividad antifungica.

Contenido de flavonoides y compuestos fenólicos de mieles chilenas e índice antioxidante

A comparison of the phenolic content of several Chilean honeys showed great variations in flavonoid concentration among the samples analysed. Higher amounts of phenolics are found in honey from dry climates. The antioxidant effect of extracts, using ORAC analysis, did not correlate with the flavonoid content or with the total phenolic concentration.

The medicinal value of honey: a review on its benefits to human health, with a special focus on its effects on glycemic regulation

Honey, a natural substance produced by honeybees, is composed of a complex mixture of carbohydrates, water, and a small amount of proteins, vitamins, minerals, and phenolic compounds. Fructose, glucose and maltose are among the various types of sugars present in honey. Used for millennia as both food and medicine, honey has been associated with improved antioxidant capacity, modulation of the immune system, antimicrobial activities, influence on lipid values (through antihypercholesterolemic effects) and regulation of glycemic responses, among other benefits. The aim of this article was to review the effects of natural honey intake on human health, with particular reference to its influence on glycemic regulation. Several studies have focused on the potential use of honey as a nutritional supplement for healthy individuals and for those with impaired glucose tolerance, diabetes, and their related comorbidities. Such investigations have found that, compared to glucose and sucrose, the consumption of honey decreases glycemic levels and blood lipids in healthy, diabetic and hyperlipidemic individuals. Moreover, long periods of honey intake seem to reduce fasting glucose levels in humans, suggesting that honey consumption influences plasma glucose regulation, mainly through a normo- or hypoglycemic effect. Therefore, honey may be proposed as a nutritional dietary supplement for healthy individuals and for those suffering from alterations in glycemic regulation

Triterpenoidal lupin saponins from the Chilean legume Lupinus oreophilus Phil.

Two lupin saponins, 3beta,21alpha,22beta,24-tetrahydroxyolean-12-en-3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21-O-alpha-L-arabinopyranoside and 3beta,21alpha,22beta,24-tetrahydroxyolean-12-en-3-O-beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21-O-alpha-L-rhamnopyranoside, along with eight other saponins and one triterpene previously reported from other legumes, were isolated from the aerial parts of Lupinus oreophilus collected in northern Chile. The structures of the isolated compounds were established with the help of extensive spectroscopic techniques.