Genotype-environment associations support a mosaic hybrid zone between two tidal marsh birds.
Genotype-environment associations support a mosaic hybrid zone between two tidal marsh birds.
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DOI：
10.1002/ece3.1864
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发表时间：
2016-01
影响因子：
2.6
通讯作者：
Kovach AI
中科院分区：
文献类型：
--
作者：
Walsh J;Rowe RJ;Olsen BJ;Shriver WG;Kovach AI
当地的环境特征可以塑造杂交区动态时，杂种有界的生态交错带或斑块分布的栖息地类型导致相应的镶嵌基因型。我们研究了沼泽水平特征在形成两个最近分化的鸟类类群之间的杂交区中的作用- Saltmarsh（Ammodramus caudacutus）和纳尔逊（A. nelsoni）麻雀。这些物种占据不同的生态位，其中异地，尾尖藻仅限于沿海沼泽，而纳尔逊藻在更广泛的湿地和草原栖息地中发现，并在同域的潮汐沼泽中共同出现。我们确定了栖息地类型对纯麻雀和杂交麻雀分布的影响，并评估了每个类群的生态位重叠的程度，为此，我们从34个沼泽地的杂交区和邻近地区的305只麻雀进行了采样和基因分型。我们使用线性回归测试之间的关联沼泽特性和纯麻雀和混合麻雀的分布。我们发现，基因型和环境变量之间的正相关性与基因型和栖息地在整个混合区的斑块状分布。生态位模型表明，混合生态位更接近于A. nelsoni，生境适宜性受到距离海岸线的强烈影响。我们的研究结果支持马赛克模型的混合区维护，建议的作用，当地的环境特征，在塑造分布和频率的纯物种和杂种在整个空间。
Local environmental features can shape hybrid zone dynamics when hybrids are bounded by ecotones or when patchily distributed habitat types lead to a corresponding mosaic of genotypes. We investigated the role of marsh‐level characteristics in shaping a hybrid zone between two recently diverged avian taxa – Saltmarsh (Ammodramus caudacutus) and Nelson's (A. nelsoni) sparrows. These species occupy different niches where allopatric, with caudacutus restricted to coastal marshes and nelsoni found in a broader array of wetland and grassland habitats and co‐occur in tidal marshes in sympatry. We determined the influence of habitat types on the distribution of pure and hybrid sparrows and assessed the degree of overlap in the ecological niche of each taxon. To do this, we sampled and genotyped 305 sparrows from 34 marshes across the hybrid zone and from adjacent regions. We used linear regression to test for associations between marsh characteristics and the distribution of pure and admixed sparrows. We found a positive correlation between genotype and environmental variables with a patchy distribution of genotypes and habitats across the hybrid zone. Ecological niche models suggest that the hybrid niche was more similar to that of A. nelsoni and habitat suitability was influenced strongly by distance from coastline. Our results support a mosaic model of hybrid zone maintenance, suggesting a role for local environmental features in shaping the distribution and frequency of pure species and hybrids across space.