McCoy-Sulentic Miles E, Kolb Thomas E, Merritt David M, Palmquist Emily C, Ralston Barbara E, Sarr Daniel A
School of Forestry Northern Arizona University Fort Collins USA.
USDA Forest Service National Stream and Aquatic Ecology Center Fort Collins CO USA.
Ecol Evol. 2017 Apr 17;7(11):3732-3744. doi: 10.1002/ece3.2975. eCollection 2017 Jun.
Wetland indicator status (WIS) describes the habitat affinity of plant species and is used in wetland delineations and resource inventories. Understanding how species-level functional traits vary across WIS categories may improve designations, elucidate mechanisms of adaptation, and explain habitat optima and niche. We investigated differences in species-level traits of riparian flora across WIS categories, extending their application to indicate hydrologic habitat. We measured or compiled data on specific leaf area (SLA), stem specific gravity (SSG), seed mass, and mature height of 110 plant species that occur along the Colorado River in Grand Canyon, Arizona. Additionally, we measured leaf δC, δN, % carbon, % nitrogen, and C/N ratio of 56 species with C3 photosynthesis. We asked the following: (i) How do species-level traits vary over WIS categories? (ii) Does the pattern differ between herbaceous and woody species? (iii) How well do multivariate traits define WIS categories? (iv) Which traits are correlated? The largest trait differences among WIS categories for herbaceous species occurred for SSG, seed mass, % leaf carbon and height, and for woody species occurred for height, SSG, and δC. SSG increased and height decreased with habitat aridity for both woody and herbaceous species. The δC and hence water use efficiency of woody species increased with habitat aridity. Water use efficiency of herbaceous species increased with habitat aridity via greater occurrence of C4 grasses. Multivariate trait assemblages differed among WIS categories. Over all species, SLA was correlated with height, δC, % leaf N, and C/N; height was correlated with SSG and % leaf C; SSG was correlated with % leaf C. Adaptations of both herbaceous and woody riparian species to wet, frequently inundated habitats include low-density stem tissue. Adaptations to drier habitats in the riparian zone include short, high-density cavitation-resistant stem tissue, and high water use efficiency. The results enhance understanding about using traits to describe plant habitat in riparian systems.
湿地指示状态（WIS）描述了植物物种对栖息地的亲和力，用于湿地划定和资源清查。了解物种水平的功能性状如何在WIS类别之间变化，可能会改进湿地指定，阐明适应机制，并解释栖息地适宜性和生态位。我们研究了河岸植物群在WIS类别中的物种水平性状差异，将其应用扩展到指示水文栖息地。我们测量或收集了亚利桑那州大峡谷科罗拉多河沿岸110种植物的比叶面积（SLA）、茎比重（SSG）、种子质量和成熟高度的数据。此外，我们测量了56种具有C3光合作用的植物的叶片δC、δN、碳含量百分比、氮含量百分比和C/N比。我们提出了以下问题：（i）物种水平性状在WIS类别之间如何变化？（ii）草本植物和木本植物的模式是否不同？（iii）多变量性状对WIS类别的定义效果如何？（iv）哪些性状相关？草本植物在WIS类别之间最大的性状差异出现在SSG、种子质量、叶片碳含量百分比和高度方面，而木本植物的最大性状差异出现在高度、SSG和δC方面。对于木本植物和草本植物来说，SSG随着栖息地干旱程度的增加而增加，高度则随着栖息地干旱程度的增加而降低。木本植物的δC以及因此的水分利用效率随着栖息地干旱程度的增加而增加。草本植物的水分利用效率随着栖息地干旱程度的增加而增加，这是通过C4草本植物的更多出现实现的。多变量性状组合在WIS类别之间存在差异。在所有物种中，SLA与高度、δC、叶片氮含量百分比和C/N相关；高度与SSG和叶片碳含量百分比相关；SSG与叶片碳含量百分比相关。草本和木本河岸物种对湿润、经常被淹没的栖息地的适应包括低密度的茎组织。河岸带对较干燥栖息地的适应包括短而高密度的抗空化茎组织以及高水分利用效率。这些结果增强了对利用性状描述河岸系统中植物栖息地的理解。
