Habitat segregation and hypothesized biotic interactions among coexisting gar species may confound attempts to describe the distributions of these species by using only macrohabitat availability in the presence of conspecifics. However, the strength of interactions among gar species and the spatial scale at which they occur are largely unknown. We used an existing data set to evaluate the co‐occurrence patterns (i.e., random assemblages versus species co‐occurring more or less than expected at random) of three gar species in 62 dynamic river–floodplain habitats associated with the lower Mississippi River and its major tributaries. A novel parameterization of a multispecies occupancy model was utilized to examine the spatial relationships among the full array of possible gar assemblages across a gradient of floodplain habitats. Spotted Gar Lepisosteus oculatus were the most abundant and frequently encountered species (~78% of samples). Shortnose Gar L. platostomus (~27% of samples) and Longnose Gar L. osseus (~12% of samples) were relatively uncommon, and no Alligator Gar Atractosteus spatula were captured in over 600 electrofishing transects. Estimated detection probabilities of the encountered species varied (range = 0.27 [Longnose Gar] to 0.80 [Spotted Gar]), and five species‐specific environmental and sampling covariates predicted detection. Relatively strong co‐occurrence patterns between Shortnose Gar and Longnose Gar were significantly influenced by the proximity of a floodplain lake to a river (i.e., river : lake elevation change and linear distance) and by lake latitude. In contrast, the occurrence patterns of Spotted Gar were largely independent of the other species and had minor influences on the relationship between Longnose Gar and Shortnose Gar. We demonstrate how species co‐occurrence patterns can be leveraged to reduce uncertainty associated with species‐specific occupancy estimates and how species distribution models can be improved by utilizing abiotic and biotic features of the target ecosystems.

中文翻译：

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河—洪泛区生境中Gar的发生与共生模式：利用物种共存的方法进行利益分配的模型

共存种之间的栖息地隔离和假设的生物相互作用可能会混淆尝试通过在同种生物存在的情况下仅使用大型栖息地来描述这些物种的分布。然而，种之间相互作用的强度以及它们发生的空间尺度在很大程度上是未知的。我们使用现有数据集来评估与密西西比河下游及其下游地区相关的62个动态河-洪泛平原生境中三种three的共生模式（即随机组合与随机多于或少于预期的物种共生）主要支流。一种新型的多物种居住模型参数化技术被用来检查整个洪泛平原生境梯度上可能的族组合的全部阵列之间的空间关系。斑Gar斜纹夜蛾是最丰富和经常遇到的物种（约占样本的78％）。Shortnose Gar L. platostomus（〜27％的样品）和Longnose Gar L. osseus（〜12％的样品）比较少见，没有鳄鱼皮的Atractosteus刮刀被捕获在600多个电钓鱼样带中。遇到的物种的估计检测概率各不相同（范围为0.27 [Longnose Gar]至0.80 [Spotted Gar]），并且五种特定于物种的环境和采样协变量预测了检测。洪泛区湖泊与河流的接近程度（即河流：湖泊高程变化和线性距离）和湖泊纬度显着影响了Shortnose Gar和Longnose Gar之间相对较强的共生模式。相反，斑点雀Gar的发生方式在很大程度上与其他物种无关，并且对Longnose Gar和Shortnose Gar之间的关系影响较小。