Claudia Alvarez-Aquino

Seedling bank dynamics of Fagus grandifolia var. mexicana before and after a mast year in a Mexican cloud forest

Abstract Fagus grandifolia var. mexicana seedling dynamics were studied in a relict forest inside the crater of a volcano where it is the only canopy tree species. The objectives of the study were (1) to determine changes in seedling density before and after a mast year, as well as to monitor seedling recruitment, mortality and growth rate in relation to the micro-environment, and (2) to discuss the impact of masting on seedling dynamics of the population. Before masting, seedling density was 8.8 seedlings m–2, afterwards seedling density peaked at 51.5 seedlings m–2, then decreased by 50% in 3 months and by 85% after 8 months, down to levels of before the mast year (9.9 seedlings m–2) after 16 months. Seedlings in the forest floor before the mast-seeding event showed a low relative growth rate − 0.14 mm mm–1 mo–1 against 1.27 mm mm–1 mo–1 for seedlings that emerged immediately after masting. Seed germination was high (83%) and rapid (L50 = 7 days) following masting. Seedling growth was positively correlated with soil water content but not with temperatures and relative humidity. Data suggested that seed production in mast years is important in maintaining the seedling bank, and thus the viability of relict Fagus populations. Abbreviations: PAR = Photosynthetically active radiation; RGR = Relative growth rate.

Tropical Dry Forest Landscape Restoration in Central Veracruz, Mexico

The refuge program aims to conserve both this salamander and traditional agriculture. We are generating a market for farm products that will include the cost of saving local culture, Xochimilco, and axolotls. Restoration of the axolotl is a complex process that must be discussed among stakeholders (such as local government, fishermen, and tourists) in order to produce multiple actions and a monitoring program. Declining axolotl populations in the wild do not leave much time or room for mistakes. But a good restoration process will bring not only increased axolotl populations but also other benefits from a functioning wetland and better market opportunities for chinamperos.

Temporal variation in the behavior of Apis mellifera (Hymenoptera: Apidae) and Lycastrirhyncha nitens (Diptera: Syrphidae) on Pontederia sagittata (Commelinales: Pontederiaceae) inflorescences in relation to nectar availability

Abstract Insect-pollinated plants offer nectar as the main reward, which influences the preference of flower visitors. We describe the feeding behavior of the exotic bee Apis mellifera (L.) (Hymenoptera: Apidae) and the flower fly Lycastrirhyncha nitens (Bigot) (Diptera: Syrphidae) on tristylous flowers of Pontederia sagittata (C. Presl) (Commelinales: Pontederiaceae) in relation to temporal nectar availability. The production of this resource was similar between floral morphs but there were temporal variations during the anthesis period, in a coincidence with a higher number of visitors and activity of bees and flies. The dynamics of nectar production could be related to the feeding behavior of these insects despite the similarity in daily nectar volume produced in all the 3 types of flowers. The variations of nectar feeding may affect the transportation of pollen among the 3 floral morphs.