Responses of common and successional heathland species to manipulated salt spray and water availability

Abstract

Coastal sandplain heathlands are a rare plant community in the northeastern United States. Salt spray and water availability are likely important factors determining heathland distribution. Field surveys and manipulative experiments were performed to examine heathland species' responses to salt spray and water availability. We surveyed field distributions of four typical heathland species: Solidago puberula, Solidago rugosa, Gaylussacia baccata, and Myrica pensylvanica. The distributions of two native tree species, Pinus rigida and Quercus ilicifolia, were also surveyed because they succeed into coastal heathlands with low disturbance frequency. We then manipulated salt spray and water in the field and measured species' water status, necrosis, and growth responses to the treatments. Predawn xylem pressure potential and necrosis were strongly affected by high salt spray and low water availability. Shoot elongation was also limited in S. puberula and S. rugosa grown in high salt, low water treatments. Gaylussacia baccata and Q. ilicifolia were particularly sensitive to high salt spray and low water, suggesting that they might excluded be from areas with those conditions. The interaction between salt spray and water availability could affect the landscape scale and should be incorporated into conservation management plans.

Responses of Kyllinga peruviana Lam. to Sea Water Spray

“…The collectors were fixed on the ground with about 20 cm of the upper part exposed. The beaker was to collect precipitation and prevent loss of trapped water (Griffiths & Orians, 2003;Doomen et al, 2006;De Vos et al, 2010;Conolly et al, 2010). The seawater was stored in a 5-L plastic jug and kept in a refrigerator at 4 °C and used for the duration of the experiment.…”

“…The soil had 5.48 pH, 20.42 ppm N, 3.56 ppm P, 3.56 (meg/100g) K, 2.32 (meg/100g) Ca, 2.60 (meg/100g) Mg, 8.2 (meg/100g) CEC, 3.67% C, 80.68% sand, 12.06% silt and 8.36% clay (Kekere & Bamidele, 2012). It is typical of a beach soil which is sandy and low in nutrient content, and because the soil is porous, leaching rate is high and salt does not accumulate in the root zone (Griffiths & Orians, 2003). The potted plants were placed on the greenhouse bench of Plant Science and Biotechnology Department, Adekunle Ajasin University, Akungba Akoko, Ondo State, Nigeria (Lat.…”

“…The stomata number per leaf was estimated as the product of stomata density and leaf area. The area of leaf tissue with necrotic damage was measured using a dot grid and expressed as the percentage of total leaf area showing necrosis (Griffiths & Orians, 2003;Griffiths et al, 2006).…”

“…They also stated that salt spray increases water content in some plants, which is an adaptation for ion dilution (Rozema et al, 1985;De Vos et al, 2010). Also, salt spray disrupts water balance in plants, and only the tolerant species can adjust osmotically through reduced xylem water potential (Griffiths & Orians, 2003;Griffiths, 2006). Thus, plant species growing in the strandline have adapted to salt spray in various ways (Rozema et al, 1985).…”

“…It suppresses plant growth, disrupts water balance, membranes and enzyme systems (Rozema et al, 1985), inhibits nutrient uptake (Scheiber et al, 2008) and causes necrotic damage (Griffiths & Orians, 2003;Griffiths et al, 2006). Air-borne salt led to a reduction in shoot and root growth in Triplasis purpurea (Cheplick & Demetri, 1999), Leymus mollis (Gagne & Houle, 2002), Myrica pensylvanica (Griffiths & Orians, 2003), Crambe maritima (De Vos et al, 2010). Diodia maritima (Kekere & Bamidele, 2012) and Commelina erecta subsp maritima (Kekere, 2013).…”