Genetic Structure and Early Effects of Inbreeding in Fragmented Temperate Forests of a Self-Incompatible Tree, Embothrium Coccineum

• Published in: Conservation biology Vol. 21; no. 1; pp. 232 - 240
• Main Authors: MATHIASEN, PAULA, ROVERE, ADRIANA E, PREMOLI, ANDREA C
• Format: Journal Article
• Language: English
• Published: Malden, USA Blackwell Publishing Inc 01.02.2007; Blackwell Science; Blackwell; Blackwell Publishing Ltd
• Subjects: Alleles; Animal, plant and microbial ecology; Applied ecology; Aves; Biological and medical sciences; bosque templado; Chile; Conservation; Conservation biology; Conservation of Natural Resources; Conservation, protection and management of environment and wildlife; Deforestation; diversidad genética; Forest genetics; Forests; fragmentación; fragmentation; Fundamental and applied biological sciences. Psychology; General aspects; Genetic diversity; Genetic Variation; Genetics, Population; Inbreeding; Isoenzymes - genetics; outcrossing rates; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; Pero; Plants; Population Density; Population genetics; Population size; progeny vigor; Proteaceae - genetics; Seedlings; Seedlings - growth & development; tamaño poblacional; tasas de exogamia; temperate forest; Trees; vigor de la progenie; Chile; temperate forest; outcrossing rates; Population number; Genetic diversity; Population genetics; population size; Fragmentation; progeny vigor; Progeny; Tree; Inbreeding; Vigor; Temperate forests; Environmental protection
• ISSN: 0888-8892; 1523-1739
• DOI: 10.1111/j.1523-1739.2006.00565.x

Deforestation of temperate forests has created landscapes of forest remnants in matrices of intense human use. We studied the genetic effects of fragmentation in southern Chile on Embothrium coccineum J.R. et G. Forster, an early colonizing, bird-pollinated tree. We tested the hypothesis that, because of its self-incompatibility and life-history strategy, E. coccineum is less strongly affected by fragmentation. We studied the effects of reduced population size and increased isolation on population genetic structure and early performance of progeny. Samples were collected from spatially isolated trees and six fragments of differing sizes (small, 1 ha; medium, 20 ha; large, >150 ha). Based on isozyme polymorphisms we estimated parameters of genetic diversity, divergence, and inbreeding for adults and greenhouse-grown progeny. We also measured germination, seedling growth, and outcrossing rates on progeny arrays. Genetic variation of adults did not correlate significantly with population size, as expected, given that fragmentation occurred relatively recently. Weak effects of fragmentation were measured on progeny. Only adults yielded significant inbreeding. Similar total genetic diversity was found in adults and progeny. Low but significant genetic differentiation existed among adult and progeny populations. Seedling growth correlated positively with the effective number of alleles, showing deleterious effects of inbreeding on progeny. Seeds from small fragments had the highest outcrossing rates and germination success, indicating that higher pollinator activity in such fragments reduced selfing, thereby buffering genetic erosion and maintaining adaptive variation. The effects of forest fragmentation were detectable in E. coccineum, but these effects will probably not be detrimental to the viability of remnant populations because small, fragmented populations demonstrated higher levels of gene flow and lower inbreeding than larger stands. Pioneer species that are insensitive to forest clearing may be crucial in recovery plans to facilitate the establishment of species intolerant to such disturbance.