Variation in δ¹³C and δ¹⁵N within and among plant species in the alpine tundra

Figures & data

Table 1. Across all alpine tundra habitat types and habitat specific values for Pagel’s λ

	Pagel’s λ
Habitat type	δ^13C	δ^15N
All habitat types	0.29	<0.01
Fellfield	0.43	0.75
Dry meadow	0.09	<0.01
Moist meadow	0.86	<0.01
Wet meadow	1.00	0.75
Snowbank	<0.01	0.14

Bold values indicate that Pagel’s λ was significantly greater than 0 (p < .05). Values equal to 1 suggest that the trait follows a Brownian process; values equal to 0 reflect the absence of any phylogenetic correlation; intermediate values indicate a weaker effect than expected from a Brownian motion model (Felsenstein 1985).

Figure 1. Variation in (a) δ¹³C and (b) δ¹⁵N among habitat types in alpine tundra. Each data point represents a species-level mean. The longer horizontal line represents the mean value for each habitat type and shorter horizontal lines represent the standard error of the mean. Letters represent significant differences among habitat types based on Tukey’s post hoc comparisons.

Figure 2. Intraspecific variation in δ¹³C among species sampled in multiple habitat types in alpine tundra. Habitats with no data points indicate that species was not present in that habitat type. The longer horizontal line represents the mean value for each habitat type and shorter horizontal lines represent one standard deviation. Letters represent significant differences among habitat types based on Tukey’s post hoc comparisons. Species codes: (a) Artemisia scopulorum (Artsco); (b) Bistorta bistortoides (Bisbis); (c) Caltha leptosepala (Callep); (d) Carex rupestris (Carrup); (e) Carex scopulorum (Carsco); (f) Deschampsia caespitosa (Desces); (g) Erigeron simplex (Erisim); (h) Festuca brachyphylla (Fesbra); (i) Geum rossii (Geuros); (j) Kobresia myosuroides (Kobmyo); (k) Lloydia serotina (Lloser); (l) Luzula spicata (Luzspi); (m) Mertensia lanceolate (Merlan); (n) Minuartia obtusiloba (Minobt); (o) Oreoxis alpina (Orealp); (p) Ranunculus adoneus (Ranado); (q) Silene acaulis (Silaca); (r) Tetraneuris acaulis (Tetaca); (s) Trifolium dasyphyllum (Tridas); (t) Trifolium parryi (Tripar).

Figure 3. Intraspecific variation in δ¹⁵N among species sampled in multiple habitat types in alpine tundra. Habitats with no data points indicate that species was not present in that habitat type. The longer horizontal line represents the mean value for each habitat type and shorter horizontal lines represent one standard deviation. Letters represent significant differences among habitat types based on Tukey’s post hoc comparisons. Species codes: (a) Artemisia scopulorum (Artsco); (b) Bistorta bistortoides (Bisbis); (c) Caltha leptosepala (Callep); (d) Carex rupestris (Carrup); (e) Carex scopulorum (Carsco); (f) Deschampsia caespitosa (Desces); (g) Erigeron simplex (Erisim); (h) Festuca brachyphylla (Fesbra); (i) Geum rossii (Geuros); (j) Kobresia myosuroides (Kobmyo); (k) Lloydia serotina (Lloser); (l) Luzula spicata (Luzspi); (m) Mertensia lanceolate (Merlan); (n) Minuartia obtusiloba (Minobt); (o) Oreoxis alpina (Orealp); (p) Ranunculus adoneus (Ranado); (q) Silene acaulis (Silaca); (r) Tetraneuris acaulis (Tetaca); (s) Trifolium dasyphyllum (Tridas); (t) Trifolium parryi (Tripar).

Figure 4. Phylogenetic patterns of variation in (a) δ¹³C and (b) δ¹⁵N among plant species in alpine tundra across all alpine tundra habitat types. We found a weak phylogenetic signal in δ¹³C (Pagel’s λ = 0.29) where phylogenetic signal was significantly greater than 0 (p = .004).

Felsenstein, J. 1985. Phylogenies and the comparative method. American Naturalist 125:1–15. doi:https://doi.org/10.1086/284325.

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