“Bartram’s Bass” Micropterus sp. cf. coosae is endemic to the upper Savannah River basin of the southeastern United States and is threatened by hybridization with invasive Alabama Bass Micropterus henshalli. Bartram’s Bass have been functionally extirpated from reservoirs, and hybrid individuals have been detected in several tributaries. However, the extent of introgression in tributaries is currently unknown. Our objectives were to (1) assess the distribution of Bartram’s Bass, native Largemouth Bass M. salmoides, invasive Alabama Bass, and their hybrids in streams of the upper Savannah River basin and (2) quantify effects of abiotic variables on the distribution of each species. We sampled 154 locations in 2017 and 2018 and assigned genetic identity using hydrolysis probes and microsatellites. We␣used conditional inference trees to quantify variables affecting the occurrence of each species and hybrids. We observed widespread hybridization across the basin. Pure Bartram’s Bass were collected at 27% (42) of sites, among which only 12 sites contained pure Bartram’s Bass and no other congeners. Thirty sites where pure Bartram’s Bass were collected contained hybrids. In the montane Blue Ridge ecoregion, occurrence of pure Bartram’s Bass was negatively affected by low levels of local-scale developed land cover. In the lower-relief Piedmont ecoregion, pure Bartram’s Bass were positively associated with watershed-scale forest land cover and stream gradient. Distance from a reservoir was positively associated with occurrence of pure Bartram’s Bass in both ecoregions. Pure Bartram’s Bass are likely to occur with high probability in only 16% of nonimpounded stream segments; this represents a conservative estimate, and the true number is likely lower. However, future work accounting for incomplete detection of Bartram’s Bass will help to improve confidence in true extirpations. Conservation efforts may be more successful if implemented on stream segments farther from reservoirs or upstream of dispersal barriers preventing colonization of Alabama Bass.

中文翻译：

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地方性 Bartram 的 Bass Micropterus sp. 的建模分布。参见 coosae：干扰和接近入侵源增加与入侵阿拉巴马鲈鱼的杂交

“Bartram's Bass” Micropterus  sp。参见 coosae是美国东南部萨凡纳河流域上游的特有种，受到与入侵的阿拉巴马州鲈鱼Micropterus henshalli杂交的威胁。Bartram's Bass 已经从水库中功能性地灭绝，并且在几个支流中发现了杂种个体。然而，目前尚不清楚支流中基因渗入的程度。我们的目标是 (1) 评估 Bartram's Bass，本地大口黑鲈M 的分布。鲑鱼、入侵的阿拉巴马州鲈鱼及其在萨凡纳河流域上游的杂种，以及 (2) 量化非生物变量对每个物种分布的影响。我们在 2017 年和 2018 年对 154 个地点进行了采样，并使用水解探针和微卫星分配了遗传身份。我们␣使用条件推理树来量化影响每个物种和杂交种发生的变量。我们观察到整个盆地广泛的杂交。在 27% (42) 的站点中收集到纯 Bartram's Bass，其中只有 12 个站点包含纯 Bartram's Bass，没有其他同类物。收集纯 Bartram's Bass 的 30 个地点包含杂交种。在山地蓝岭生态区，纯 Bartram's Bass 的出现受到当地规模开发土地覆盖水平低的负面影响。在地势较低的皮埃蒙特生态区，纯 Bartram's Bass 与流域规模的林地覆盖和河流梯度呈正相关。与水库的距离与两个生态区中纯 Bartram's Bass 的发生呈正相关。纯 Bartram's Bass 很可能仅在 16% 的未蓄水河段中出现；这是保守估计，真实数字可能更低。然而，未来对 Bartram 低音的不完整检测的解释将有助于提高对真正灭绝的信心。如果在远离水库的河段或防止阿拉巴马鲈鱼定殖的扩散障碍上游实施，保护工作可能会更成功。与水库的距离与两个生态区中纯 Bartram's Bass 的发生呈正相关。纯 Bartram's Bass 很可能仅在 16% 的未蓄水河段中出现；这是保守估计，真实数字可能更低。然而，未来对 Bartram 低音的不完整检测的解释将有助于提高对真正灭绝的信心。如果在远离水库的河段或防止阿拉巴马鲈鱼定殖的扩散障碍上游实施，保护工作可能会更成功。与水库的距离与两个生态区中纯 Bartram's Bass 的发生呈正相关。纯 Bartram's Bass 很可能仅在 16% 的未蓄水河段中出现；这是保守估计，真实数字可能更低。然而，未来对 Bartram 低音的不完整检测的解释将有助于提高对真正灭绝的信心。如果在远离水库的河段或防止阿拉巴马鲈鱼定殖的扩散障碍上游实施，保护工作可能会更成功。对 Bartram 低音的不完整检测的未来工作将有助于提高对真正灭绝的信心。如果在远离水库的河段或防止阿拉巴马鲈鱼定殖的扩散障碍上游实施，保护工作可能会更成功。对 Bartram 低音的不完整检测的未来工作将有助于提高对真正灭绝的信心。如果在远离水库的河段或防止阿拉巴马鲈鱼定殖的扩散障碍上游实施，保护工作可能会更成功。