Disruption of Leaf Nutrient Remobilization in Coastal Cycas Trees by Tropical Cyclone Damage

Abstract

We studied leaf nutrient status of Cycas nitida leaves that were damaged by Typhoon Haiyan in four contrasting locations in eastern Philippines to determine the influence of tropical cyclone (TC) damage on habitat biogeochemistry. Nitrogen resorption efficiency was below global values, but phosphorus and potassium resorption efficiencies were above global values. Stoichiometric relationships indicated P limitations, and leaf P traits tracked soil P availability. Typhoon Haiyan damage resulted in severe changes in P and K nutrient budgets for the plants, and the resulting litter was of high quality with traits that predicted rapid decomposition of the TC-generated litter. Partially desiccated leaves retained dead leaflet tissue exhibiting nutrient relations that did not differ from those of healthy green leaves, representing another means by which the TC disrupted nutrient cycling that added to the nutrients lost due to leaf abscission. Our results build on the need for a greater understanding of how TCs influence plant and community biogeochemistry and establish some background information for understanding ongoing climate change research.

Distribution of Elements along the Rachis of Cycas micronesica Leaves: A Cautionary Note for Sampling Design

“…Plants growing in impoverished soils may exhibit greater disparity of nutrient concentrations along a long leaf rachis. Our results indicate that the plants we sampled were not experiencing nutritional stress, as our data were within or greater than the published range for cycads in general [16][17][18][19][20][21][22][23][24][25] and for this species in particular [8,15,23]. As a minimum, we suggest the soil nutrient status should be measured and reported accurately in future studies [26].…”

“…One other cycad paper reported the position that was sampled, but the sampling was restricted to leaflets from the middle of the rachis [17]. The majority of cycad publications including leaf tissue analysis results provide no description of location along the rachis where leaflets were sampled [18][19][20][21][22][23][24][25]. Our findings indicate that these past publications without rachis position reported are ambiguous and the methods are not repeatable.…”

Cycas micronesica Trees Alter Local Soil Traits

“…Other papers include soil samples from the experimental sites, but they do not indicate proximity of the samples to the studied cycad plants [44]. We are aware of only two reports that included dedicated soil sampling with descriptions of proximity to the cycad plants that were being studied for green leaf nutrient content [45,46]. Continued research within this agenda must include descriptions of influential soil chemistry, and our results indicate the sampling sites must be constrained within close proximity to the studied cycad plants to enable the legitimacy of the methods.…”

Incident Light and Leaf Age Influence Leaflet Element Concentrations of Cycas micronesica Trees

“…We argue that there is a need to standardize sampling protocols and conduct more case studies to fully understand what controls leaf nutrient status of cycad species and to compare these traits with other gymnosperm and angiosperm taxa [3]. The sampling protocols have been diverse and the level of detail in sampling methods contrasts among the reports [4][5][6][7][8][9][10][11][12][13][14][15]. We have recently shown that plant size [4] and position of leaflet along the rachis [5] are two plant traits that should be recorded to ensure repeatable methods in cycad leaf nutrient studies.…”

“…Two of the plant traits that may influence leaf nutrient concentrations for a range of plants are sun exposure at the leaf level and leaf age. Details on these influential traits are missing from the methods of most published reports on cycad leaf nutrients [7][8][9][10][11][12][13][14][15]. Our objectives were to evaluate the influence of these two plant traits on variation in leaf nutrients for the arborescent Cycas micronesica, a species with a native range that includes Palau, Yap, Guam, and Rota Islands [16].…”