Determinants of functional connectivity of holm oak woodlands: Fragment size and mouse foraging behavior

FOREST ECOLOGY AND MANAGEMENT

卷:368

Article

Moran-Lopez, Teresa¹  Jose Robledo-Arnuncio, Juan²  Diaz, Mario¹  Manuel Morales, Juan³  Lazaro-Nogal, Ana¹  Lorenzo, Zaida²  Valladares, Fernando¹ 

[1] CSIC, Dept Biogeog & Global Change BCG MNCN, Museo Nacl Ciencias Nat, C Serrano 115 Bis, E-28006 Madrid, Spain

[2] INIA CIFOR, Dept Forest Ecol & Genet, Ctra Coruna Km 7-5, Madrid 28040, Spain

[3] Natl Univ Comahue, INIBIOMA CONICET, Ecotono Lab, Quintral 1250, RA-8400 San Carlos De Bariloche, Rio Negro, Argentina

关键词: Quercus ilex;    Mating network;    Seed dispersal;    Pollen dispersal;    Forest fragmentation;   

DOI  :  10.1016/j.foreco.2016.03.010

来源: Elsevier

【 摘 要 】

Demographic and genetic connectivity of fragmented plant populations will depend on effective propagule flow across the landscape. We analyze functional connectivity in a holm oak (Quercus ilex) fragmented landscape by considering three important stages driving recruitment: effective pollination, acorn production and acorn dispersal. We used a network approach to (1) determine if pollen-mediated gene exchange across the landscape was spatially structured; (2) estimate the effects of limited acorn dispersal on functional connectivity; (3) identify which landscape traits could drive source sink dynamics of gene flow. Although long distance dispersal was relatively frequent, most effective pollen flow occurred over short distances (<100 m). This resulted in a significantly modular structure of the mating network, yielding higher gene flow among nearby fragments. Limited mouse acorn hoarding activity had a strong impact on landscape connectivity, decreasing male gametic immigration rates into forest patches by one order of magnitude Besides, our results show that big forest fragments (>10 ha) are the main pollen sources, while small ones (<1 ha) are important pollen sinks. Thus, big fragments are critical to maintain functional connectivity, while small forest fragments may provide acorn crops better representing regional genetic diversity. In addition to area effects, less isolated and more central fragments showed higher migration rates and exchanged effective pollen with more fragments. Hence, we expected that landscapes with uniform or clumped distribution of big forest fragments would show optimal connectivity traits. However, despite that simulated gene flow was more evenly distributed across the landscape, connectance and migration rates decreased. Our results call for caution before translating patch-level management guidelines to the landscape scale. They also show that the level of functional connectivity may change throughout the recruitment process, suggesting that large-scale conservation strategies may fail if local effective seed establishment is disregarded. (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

Free