Mississippi Field Station, National Wildlife Research Center, Wildlife Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, Mississippi State, Mississippi, United States of America.
National Warmwater Aquaculture Center, Mississippi State University, Stoneville, Mississippi, United States of America.
PLoS One. 2023 Apr 13;18(4):e0284265. doi: 10.1371/journal.pone.0284265. eCollection 2023.
Agricultural development has been causing changes to the environment and the abundance and distribution of avian species. Agriculture is dynamic with changes in products occurring at large scales over relatively short time periods. The catfish aquaculture industry is one such agriculture industry that has undergone dramatic changes over the last 25 years. The double-crested cormorant (Nannopterum auritum) is a piscivorous bird that has an extensive history with the aquaculture industry of Mississippi due to its depredation of cultured catfish. A large-scale monitoring program began in 1989 to estimate the abundance and location of cormorants at every known roost in the primary catfish producing region of the state, regionally known as the Delta. We used this data set to address hypotheses pertaining to cormorant ecology within the Delta over time, particularly in relation to aquaculture. We found that, although the Midwest breeding population of cormorants has been increasing, the abundance of cormorants wintering in the Delta has been decreasing, closely following the decline of aquaculture, suggesting aquaculture area is the primary reason for cormorant inhabitation of the region. We also modeled cormorant presence and abundance at all roost sites to determine what factors most influenced cormorant distribution. Aquaculture area around roosts was a significant predictor of both cormorant presence and abundance. However, the influence of aquaculture area was seasonally dependent, with greater positive influences occurring prior to migration. Lastly, we found peak cormorant abundance in the Delta is occurring 2.14 days earlier each year, which may be indicative of changes to migration phenology. Information gained using this large dataset aids in cormorant damage mitigation and to further our understanding of cormorant ecology. Data indicate changes in agriculture, and potentially climate change, can influence phenology, distribution, and abundance of avian species at large geographic scales.
农业发展导致了环境变化以及鸟类物种的丰富度和分布变化。农业是动态的，产品在相对较短的时间内发生大规模变化。鲶鱼养殖业就是这样一个在过去 25 年经历了巨大变化的农业产业。双冠鸬鹚（Nannopterum auritum）是一种食鱼鸟类，由于其对养殖鲶鱼的捕食，在密西西比州的水产养殖业中有着悠久的历史。一个大规模的监测计划始于 1989 年，旨在估计在该州主要鲶鱼养殖区（该地区称为三角洲）的每个已知栖息地的鸬鹚数量和位置。我们利用这个数据集来解决与三角洲地区鸬鹚生态学有关的假设，特别是与水产养殖有关的假设。我们发现，尽管中西部鸬鹚繁殖种群数量一直在增加，但在三角洲地区越冬的鸬鹚数量却在减少，这与水产养殖的减少密切相关，这表明水产养殖面积是鸬鹚栖息在该地区的主要原因。我们还对所有栖息地的鸬鹚存在和数量进行了建模，以确定哪些因素对鸬鹚分布的影响最大。栖息地周围的水产养殖面积是影响鸬鹚存在和数量的重要因素。然而，水产养殖面积的影响是季节性的，在迁徙前的影响更大。最后，我们发现三角洲地区鸬鹚数量的峰值每年提前 2.14 天出现，这可能表明迁徙物候学发生了变化。利用这个大数据集获得的信息有助于减轻鸬鹚的危害，并进一步了解鸬鹚的生态学。数据表明，农业的变化，以及潜在的气候变化，可以在大地理范围内影响鸟类物种的物候学、分布和丰度。
