Porazinska Dorota L, Pratt Paul D, Glblin-Davis Robin M
Fort Lauderdale Research and Education Center (FLREC), University of Florida, 3205 College Ave., Fort Lauderdale, FL 33314 Invasive Plant Research Lab, USDA/ARS, 3225 College Ave., Fort Lauderdale, FL 33314.
J Nematol. 2007 Dec;39(4):305-12.
The tree Melaleuca quinquenervia invades all types of habitats of South Florida leading to up to 80% loss of aboveground diversity. To examine impacts on the belowground ecosystem, we investigated the composition and diversity of nematodes from soils dominated by the invasive tree and compared them with soils supporting native plant communities at six locations across the Florida Everglades over three years. Despite the significant differences in soil type, hydrology, and native plant composition of the sites, there were consistent differences in nematode communities between soil environments under the native and invaded plant communities. The total abundance and diversity of nematodes in soils dominated by M. quinquenervia was 60% and 80% of adjacent soils under native plants. Fungal-feeding and plant-parasitic nematodes were twice as abundant under native plants as under M. quinquenervia. Nematode communities under M. quinquenervia were bacterivore-dominated, while under native vegetation plant-parasite dominated. The overall diversity of nematodes was 20% lower under the exotic than under native plants, with plant parasites being 36% and fungivores being 30% less diverse. Soil moisture, % of Ca, Mg, and clay particles and total soil C and N were greater in M. quinquenervia soils, but plant-available concentrations of P, K, Ca, and Mg as well as CEC were reduced. Overall, data suggests that the invasion process may modify soil biotic and abiotic conditions that in turn promote the advancement of the exotic M. quinquenervia and displacement of the native plants.
千层金树入侵了南佛罗里达州的所有类型栖息地，导致地上生物多样性损失高达80%。为了研究其对地下生态系统的影响，我们调查了以这种入侵树种为主的土壤中线虫的组成和多样性，并在三年时间里，将其与佛罗里达大沼泽地六个地点支持本地植物群落的土壤进行了比较。尽管这些地点的土壤类型、水文条件和本地植物组成存在显著差异，但本地植物群落和入侵植物群落之下的土壤环境中线虫群落存在一致的差异。千层金树为主的土壤中线虫的总丰度和多样性分别是本地植物相邻土壤的60%和80%。以真菌为食和植物寄生线虫在本地植物下的数量是千层金树下的两倍。千层金树下的线虫群落以食细菌线虫为主，而在本地植被下则以植物寄生线虫为主。外来植物下的线虫总体多样性比本地植物下低20%，其中植物寄生线虫多样性低36%，食真菌线虫多样性低30%。千层金树土壤中的土壤湿度、钙、镁和粘土颗粒百分比以及土壤总碳和总氮含量更高，但植物可利用的磷、钾、钙和镁浓度以及阳离子交换量降低。总体而言，数据表明入侵过程可能会改变土壤生物和非生物条件，进而促进外来千层金树的生长以及本地植物的被取代。
