Seed rain and seedling emergence of Fagus grandifolia subsp. mexicana at La Mojonera, Hidalgo, Mexico

Abstract

FAGUS GRANDIFOLIA SUBSP. MEXICANA IS A SPECIES RESTRICTED TO SMALL POPULATIONS UNDER HIGH ANTHROPOGENIC PRESSURE. WITH THE AIM TO ATTAIN INFORMATION TO PROPOSE CONSERVATION STRATEGIES OF THIS SPECIES, THE SEED RAIN AND DEMOGRAPHY OF CURRENT-YEAR SEEDLINGS WERE ANALYZED AT LA MOJONERA, HIDALGO, MEXICO. A 4 800 M2 PLOT DIVIDED INTO 10 X 10 M QUADRANTS WAS ESTABLISHED. THE SEED RAIN, SEEDLING EMERGENCE, AND SURVIVAL WERE ANALYZED USING SEED TRAPS OF 0.5 M2 AND ADJACENT 1 M2 SUB-PLOTS. THE TOTAL SEED RAIN WAS 521 667 SEEDS HA-1. A HIGH PROPORTION OF SEEDS WERE UNSOUND (46.01%), FOLLOWED BY DAMAGED SEEDS (29.5%) AND ONLY 24.44% WERE SOUND. EMERGED SEEDLINGS FL UCTUATED FROM 1 TO 33 SEEDLINGS M2. AFTER 10 MONTHS, 2.8% OF EMERGED SEEDLINGS WERE ALIVE. SEEDLINGS THAT EMERGED FIRST SHOWED HIGHER SURVIVAL PROBABILITY. IMPORTANT MORTALITY CAUSES WERE HERBIVORY (34.44%), DAMPING-OFF (24.07%) AND UNKNOWN CAUSES (23.65%). THIS SPECIES PRESENTS THE GENERAL PATTERN OF TREE SPECIES IN SEEDLINGS SURVIVAL, SHOWING A HIGH MORTALITY RATE DURING THE FIRST YEAR.