Ecological stoichiometry and strategies of plants belonging different habitats in Kızılırmak Delta

Öz

Kızılırmak Delta (Samsun, Türkiye) comprises a fine-scale mosaic of wetlands and saline/halophytic habitats, where strong environmental gradients may influence plant nutrient-use patterns and ecological strategies. Here, we evaluated how leaf stoichiometry (N, P, N:P) and CSR-based strategies vary across contrasting habitats and how these traits relate to measured soil and water chemistry. The dataset comprised 39 observations from nine terrestrial plant taxa sampled in three wetland localities (Balık, Cernek, and Liman lakes) and one saline area dominated by halophytes. Habitat differences were tested using Welch’s t tests; trait–environment relationships were assessed using correlations and redundancy analysis (RDA). Halophyte sites exhibited markedly higher salinity indicators (EC, TDS) and higher soil phosphorus (P) levels. In contrast, wetlands had higher soil pH and higher inorganic N forms (NH₄ and NO₂+NO₃) and total soil N. Leaf N was significantly higher in wetlands. In contrast, leaf P and community-level N:P did not differ significantly between habitats, despite significant differences in soil P. Leaf N declined with increasing TDS and soil P. RDA separated habitats along a salinity–nutrient gradient, with environmental predictors explaining ~19% of the variance in stoichiometric responses. Competitive categories across taxa dominated CSR assignments. Overall, the results indicate that salinity and nutrient form/availability jointly structure habitat differences in plant stoichiometry in Kızılırmak Delta, with nitrogen showing the strongest habitat signal.

Anahtar Kelimeler

• nutrient limitation
• functional traits
• habitat filtering
• salinity stress
• coastal wetland

Kızılırmak Deltası'nda farklı habitatlara ait bitkilerin ekolojik stokiyometrisi ve stratejileri

Öz

Kızılırmak Deltası (Samsun, Türkiye), sulak alanlar ile tuzlu/halofit habitatların iç içe geçtiği ve güçlü çevresel gradyanların görüldüğü bir mozaik sistemdir. Bu çalışmada, farklı habitatlarda yaprak stokiyometrisinin (N, P, N:P) ve CSR temelli stratejilerin nasıl değiştiği ve bu biyolojik örüntülerin toprak/su kimyasıyla nasıl ilişkili olduğu incelenmiştir. Veri seti, üç sulak alan lokalitesi (Balık, Cernek ve Liman gölleri) ile halofitlerin baskın olduğu bir tuzlu alandan örneklenen dokuz karasal bitki taksonuna ait toplam 39 gözlemi içermektedir. Habitat farkları Welch t testi ile değerlendirilmiş; özellik–çevre ilişkileri korelasyonlar ve redundans analizi (RDA) ile özetlenmiştir. Halofit habitatında EC ve TDS değerleri ile toprak P daha yüksek bulunurken; sulak alanlarda toprak pH’ı, inorganik N formları (NH₄ ve NO₂+NO₃) ve toplam toprak N daha yüksektir. Yaprak N sulak alanlarda anlamlı biçimde daha yüksekken, yaprak P ve topluluk düzeyinde N:P habitatlar arasında anlamlı farklılık göstermemiştir; bu durum, toprak P’daki büyük farklılıklara rağmen yaprak P’nin daha güçlü fizyolojik düzenleme/uyum mekanizmalarıyla kontrol edilebileceğine işaret etmektedir. Yaprak N, artan TDS ve toprak P ile azalma eğilimi göstermiş; RDA, örnekleri tuzluluk–besin gradyanı boyunca ayırmış ve çevresel değişkenler stokiyometrik varyansın yaklaşık %19’unu açıklamıştır. Sonuçlar, deltada özellikle azotun habitat farklılaşmasına en duyarlı stokiyometrik bileşen olduğunu göstermektedir.

Anahtar Kelimeler

• besin elementi sınırlılığı
• işlevsel özellikler
• habitat süzgeci
• tuzluluk stresi
• kıyı sulak alanı

Kaynakça

1. Aerts R, Chapin FS (2000). The mineral nutrition of wild plants revisited: a re-evaluation of processes and patterns. Advances in Ecological Research 30: 1-67.
2. Akcin A, Yalcin E. (2016). Effect of salinity stress on chlorophyll, carotenoid content, and proline in Salicornia prostrata Pall. and Suaeda prostrata Pall. subsp. prostrata (Amaranthaceae). Brazilian Journal of Botany 39(1): 101-106. https://doi.org/10.1007/s40415-015-0218-y
3. Allen SE, Grimshaw HM, Parkinson JA, Quarmby C, Roberts JD (1976). Chemical analysis. In: Chapman, S.B. (ed.) Methods in Plant Ecology. Oxford: Blackwell Scientific Publications. pp. 411-460.
4. Ameen AD, Kolke AS, Taylor CM (2017). Vegetation and shear strength in a delta-splay mouth bar. Wetlands 37(6): 1159-1168. https://doi.org/10.1007/s13157-017-0948-7
5. Arslan H (2012). Spatial and temporal mapping of groundwater salinity using ordinary kriging and indicator kriging: the case of Bafra Plain, Turkey. Agricultural Water Management 113: 57-63.
6. Babur H, Surmen B, Kutbay HG (2021). Grime's CSR Strategies of Aquatic Macrophytes in Different Lagoon Lakes in Northern Turkey. Turkish Journal of Fisheries and Aquatic Sciences 21: 211-224. https://doi.org/10.4194/1303-2712-v21_05_01
7. Bray RH, Kurtz LT (1945). Determination of total, organic, and available forms of phosphorus in soils. Soil Science 59(1): 39-46.
8. Cahoon DR, White DA, Lynch JC (2011). Sediment infilling and wetland formation dynamics in an active crevasse splay of the Mississippi River delta. Geomorphology 131: 57-68.

9. Cornwell WK, Grubb PJ (2003). Regional and local patterns in plant species richness with respect to resource availability. Oikos 100(3): 417-428.
10. Grime JP (1977). Evidence for the existence of three primary strategies in plants and its relevance to ecological and evolutionary theory. American Naturalist 111: 1169-1194.
11. Grime JP (2002). Plant Strategies, Vegetation Processes, and Ecosystem Properties. Chichester: Wiley.
12. Güsewell S (2004). N:P ratios in terrestrial plants: variation and functional significance. New Phytologist 164: 243-266. https://doi.org/10.1111/j.1469-8137.2004.01192.x
13. Güsewell S (2005). Nutrient resorption of wetland graminoids is related to the type of nutrient limitation. Functional Ecology 19: 344-354.
14. Güsewell S, Koerselman W, Verhoeven JTA (2003). Biomass N:P ratios as indicators of nutrient limitation for plant populations in wetlands. Ecological Applications 13(2): 372-384.
15. Hodgson JG, Wilson PJ, Hunt R, Grime JP, Thompson K (1999). Allocating C-S-R plant functional types: A soft approach to a hard problem. Oikos 85: 282-294.
16. Koerselman W, Meuleman AFM (1996). The vegetation N:P ratio: A new tool to detect the nature of nutrient limitation. Journal of Applied Ecology 33: 1441-1450.
17. Mitsch WJ, Gosselink JG (1993). Wetlands. New York: Van Nostrand Reinhold.
18. Özhatay N, Byfield A, Atay S (2005). Türkiye’nin 122 Önemli Bitki Alanı. İstanbul: WWF Türkiye (Türkiye Doğal Hayatı Koruma Vakfı).
19. Pierce S, Negreiros D, Cerabolini BEL, Kattge J, Díaz S, Kleyer M, Shipley B, Wright SJ (2017). A global method for calculating plant CSR ecological strategies applied across biomes world-wide. Functional Ecology 31(2): 444-457. https://doi.org/10.1111/1365-2435.12722
20. Rainwater FH, Thakcher LL (1960). Methods for collection and analysis of water samples. Washington: Government Printing Office. pp. 216-219.
21. Roberts HH (1997). Dynamic changes of the Holocene Mississippi River delta plain: The delta cycle. Journal of Coastal Research 13(3): 605-627.
22. Sardans J, Peñuelas J (2013). Plant-soil interactions in Mediterranean forest and shrublands: Impacts of climatic change. Plant and Soil 365: 1-33. https://doi.org/10.1007/s11104-013-1591-6
23. Seidling W, Fischer R (2008). Deviances from expected Ellenberg indicator values for nitrogen are related to N throughfall deposition in forest. Ecological Indicators 8: 639-646.
24. Seidling W, Rohner MS (1993). Zusammenhänge zwischen Reaktionsindikatorwerten und Bodenparametern am Beispiel von Waldbodenvegetation. Phytocoenologia 23: 301-317.
25. Sürmen B (2021). Ecological strategies of terrestrial plant species belonging two different habitats in Kızılırmak Delta (Samsun/TURKEY). Biology Bulletin 48(6): 800-812.
26. Tüzüner A (1990). Toprak ve Su Analizleri El Kitabı. Ankara: Tarım Orman ve Köyişleri Bakanlığı Köy Hizmetleri Genel Müdürlüğü.
27. Willby NK, Pulford ID, Flowers TH (2001). Tissue nutrient signatures predict herbaceous-wetland community response to nutrient availability. New Phytologist 152: 463-481.