Environmental differences between sites control the diet and nutrition of the carnivorous plant Drosera rotundifolia

Background and Aims Carnivorous plants are sensitive to small changes in resource availability, but few previous studies have examined how differences in nutrient and prey availability affect investment in and the benefit of carnivory. We studied the impact of site-level differences in resource availability on ecophysiological traits of carnivory for Drosera rotundifolia L. Methods We measured prey availability, investment in carnivory (leaf stickiness), prey capture and diet of plants growing in two bogs with differences in N deposition and plant available N: Cors Fochno (0.62 g m⁻² yr⁻¹, 353 µg l⁻¹), Whixall Moss (1.37 g m⁻² yr⁻¹, 1505 µg l⁻¹). The total N amount per plant and the contributions of prey/root N to the plants’ N budget were calculated using a single isotope natural abundance method. Results Plants at Whixall Moss invested less in carnivory, were less likely to capture prey, and were less reliant on prey-derived N (25.5% compared with 49.4%). Actual prey capture did not differ between sites. Diet composition differed – Cors Fochno plants captured 62% greater proportions of Diptera. Conclusions Our results show site-level differences in plant diet and nutrition consistent with differences in resource availability. Similarity in actual prey capture may be explained by differences in leaf stickiness and prey abundance

Response of Sphagnum papillosum and Drosera rotundifolia to reduced and oxidized wet nitrogen deposition

We transplanted Sphagnum 'turfs' containing abundant Drosera rotundifolia into an existing nitrogen deposition experiment at Whim Moss near Edinburgh. These mesocosms received simulated N deposition as either NH or NO , to give total N deposition rates of approximately 8, 16 or 32, or 64 kg N ha year . Simulated N deposition was added in a realistic way (i. e., with rainfall throughout the year). The δ N of this added N was elevated relative to background N. We measured the tissue chemistry and δ N of Sphagnum papillosum and D. rotundifolia over two years after transplant. Our aim was to determine uptake of the deposited N and the impact on S. papillosum tissue chemistry and D. rotundifolia tissue chemistry and ecology. We found clear, significant impacts of N deposition on S. papillosum, with increased capitula N content and reduced C:N ratio. Increased δ N indicated uptake of deposited N. The response of D. rotundifolia was less clear with impacts only at the highest rate of N deposition. There was no evidence of differential uptake of reduced or oxidized wet N deposition by either S. papillosum or D. rotundifolia. Using the natural abundance stable isotope method we estimated the minimum contribution of prey N to the total N in D. rotundifolia to be 35%. The results suggest that differences in the uptake of reduced or oxidized wet N deposition might not be ecologically significant when wet N deposition is added realistically. They also support the suggestion that a model of N dynamics in Sphagnum-dominated ecosystems that includes the role of Sphagnum as a small-scale ecosystem engineer, is required to predict vascular plant responses to N deposition accurately

Carbon and nitrogen stable isotope profiles of winter grown feathers of wood warbler (n = 71), house martin (n = 82) and common swift (n = 56).

<p>Carbon and nitrogen stable isotope profiles of winter grown feathers of wood warbler (n = 71), house martin (n = 82) and common swift (n = 56).</p

Feather sampling site locations for breeding wood warblers, house martins and common swifts.

<p>Feather sampling site locations for breeding wood warblers, house martins and common swifts.</p

Figure 1

<p>Carbon and nitrogen isotope compositions in winter grown feathers of wood warblers (a, b), house martins (c, d) and common swifts (e, f) sampled from different regions of the breeding distribution Error bars represent one standard error, and numbers represent sample size.</p

Bill size and diet in reed buntings

Bill size and diet in reed bunting

Bicknell et al - Inter-colony movement of pre-breeding seabirds - Supplementary Data

Raw stable isotope values of Leach's storm-petrel blood samples and calanus copepod CPR samples. Mixing model parameters for the original and sensitivity models with results of models comparison.Random sampling process and calculations

AA indicators of diagenesis in archaeological wool samples (grouped by site), compared to isothermal hydrolysis (median ± IQR per time point) and experimental burial [62].

<p>Analytical error indicates within-sample s.d.; arrows show time series for hydrolytic experiments; error for Asx D/L is smaller than the data point.</p

(a) δ¹³C vs δ¹⁵N values and (b) δ¹⁵N vs δ²H values for wool keratin samples (heavy solid outline) and bone collagen samples (light dotted outline).

<p>(a) δ¹³C vs δ¹⁵N values and (b) δ¹⁵N vs δ²H values for wool keratin samples (heavy solid outline) and bone collagen samples (light dotted outline).</p

Textile samples with isotope compositions outlying from respective settlement median.

<p>Textile samples with isotope compositions outlying from respective settlement median.</p