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Links between belowground and aboveground resource-related traits reveal species growth strategies that promote invasive advantages.

Smith MS, Fridley JD, Goebel M, Bauerle TL - PLoS ONE (2014)

Bottom Line: Seasonal 15N uptake was higher in spring than in the fall, which did not support the need for higher root activity to correspond with extended leaf phenology.We found higher spring 15N uptake in non-native L. japonica compared to native L. sempervirens, although there was no difference in 15N uptake between Frangula and Rhamnus species.Our findings indicate the potential for fast-growing non-native Lonicera japonica and Frangula alnus to outcompete native counterparts through differences in biomass allocation, root turnover, and nitrogen uptake, however evidence that this is a general strategy of invader dominance is limited.

View Article: PubMed Central - PubMed

Affiliation: Department of Horticulture, Cornell University, 134A Plant Science Building, Ithaca, New York, United States of America.

ABSTRACT
Belowground processes are rarely considered in comparison studies of native verses invasive species. We examined relationships between belowground fine root production and lifespan, leaf phenology, and seasonal nitrogen dynamics of Lonicera japonica (non-native) versus L. sempervirens (native) and Frangula alnus (non-native) versus Rhamnus alnifolia (native), over time. First and second order fine roots were monitored from 2010 to 2012 using minirhizotron technology and rhizotron windows. 15N uptake of fine roots was measured across spring and fall seasons. Significant differences in fine root production across seasons were seen between Lonicera species, but not between Frangula and Rhamnus, with both groups having notable asynchrony in regards to the timing of leaf production. Root order and the number of root neighbors at the time of root death were the strongest predictors of root lifespan of both species pairs. Seasonal 15N uptake was higher in spring than in the fall, which did not support the need for higher root activity to correspond with extended leaf phenology. We found higher spring 15N uptake in non-native L. japonica compared to native L. sempervirens, although there was no difference in 15N uptake between Frangula and Rhamnus species. Our findings indicate the potential for fast-growing non-native Lonicera japonica and Frangula alnus to outcompete native counterparts through differences in biomass allocation, root turnover, and nitrogen uptake, however evidence that this is a general strategy of invader dominance is limited.

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Mean ± SE of 15N (nmol ug−1 root tissue) accumulated in new first and second order fine roots during fall 2011 and spring 2012 at 6 hours of exposure to 1 mmol 15N exposure.Species are ordered from left to right: L. japonica, L. sempervirens, F. alnus, R. alnifolia.
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pone-0104189-g004: Mean ± SE of 15N (nmol ug−1 root tissue) accumulated in new first and second order fine roots during fall 2011 and spring 2012 at 6 hours of exposure to 1 mmol 15N exposure.Species are ordered from left to right: L. japonica, L. sempervirens, F. alnus, R. alnifolia.

Mentions: When the analysis was separated by individual season, roots born in the spring had approximately 100 times higher nitrate concentrations after 15N exposure than roots from the fall (Fig. 4, Table 3). During spring uptake, less than 0.01 mmol KNO3- was accumulated in the tissue until hour six, where a significant increase in uptake occurred (P<0.0001). Root initial contact time with nitrate was significant with a comparatively lower level of uptake (P = 0.042), so its effect on total uptake was minimal overall. Roots of non-native species had a mean nitrate content of 0.008±0.0007 mmol 15N µg-1 root tissue, which was significantly higher than native congeners (P = 0.009). No significant effect of time or native status was found during fall uptake (P>0.05), but there was a lower uptake trend in native plants (Fig. 4).


Links between belowground and aboveground resource-related traits reveal species growth strategies that promote invasive advantages.

Smith MS, Fridley JD, Goebel M, Bauerle TL - PLoS ONE (2014)

Mean ± SE of 15N (nmol ug−1 root tissue) accumulated in new first and second order fine roots during fall 2011 and spring 2012 at 6 hours of exposure to 1 mmol 15N exposure.Species are ordered from left to right: L. japonica, L. sempervirens, F. alnus, R. alnifolia.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4126695&req=5

pone-0104189-g004: Mean ± SE of 15N (nmol ug−1 root tissue) accumulated in new first and second order fine roots during fall 2011 and spring 2012 at 6 hours of exposure to 1 mmol 15N exposure.Species are ordered from left to right: L. japonica, L. sempervirens, F. alnus, R. alnifolia.
Mentions: When the analysis was separated by individual season, roots born in the spring had approximately 100 times higher nitrate concentrations after 15N exposure than roots from the fall (Fig. 4, Table 3). During spring uptake, less than 0.01 mmol KNO3- was accumulated in the tissue until hour six, where a significant increase in uptake occurred (P<0.0001). Root initial contact time with nitrate was significant with a comparatively lower level of uptake (P = 0.042), so its effect on total uptake was minimal overall. Roots of non-native species had a mean nitrate content of 0.008±0.0007 mmol 15N µg-1 root tissue, which was significantly higher than native congeners (P = 0.009). No significant effect of time or native status was found during fall uptake (P>0.05), but there was a lower uptake trend in native plants (Fig. 4).

Bottom Line: Seasonal 15N uptake was higher in spring than in the fall, which did not support the need for higher root activity to correspond with extended leaf phenology.We found higher spring 15N uptake in non-native L. japonica compared to native L. sempervirens, although there was no difference in 15N uptake between Frangula and Rhamnus species.Our findings indicate the potential for fast-growing non-native Lonicera japonica and Frangula alnus to outcompete native counterparts through differences in biomass allocation, root turnover, and nitrogen uptake, however evidence that this is a general strategy of invader dominance is limited.

View Article: PubMed Central - PubMed

Affiliation: Department of Horticulture, Cornell University, 134A Plant Science Building, Ithaca, New York, United States of America.

ABSTRACT
Belowground processes are rarely considered in comparison studies of native verses invasive species. We examined relationships between belowground fine root production and lifespan, leaf phenology, and seasonal nitrogen dynamics of Lonicera japonica (non-native) versus L. sempervirens (native) and Frangula alnus (non-native) versus Rhamnus alnifolia (native), over time. First and second order fine roots were monitored from 2010 to 2012 using minirhizotron technology and rhizotron windows. 15N uptake of fine roots was measured across spring and fall seasons. Significant differences in fine root production across seasons were seen between Lonicera species, but not between Frangula and Rhamnus, with both groups having notable asynchrony in regards to the timing of leaf production. Root order and the number of root neighbors at the time of root death were the strongest predictors of root lifespan of both species pairs. Seasonal 15N uptake was higher in spring than in the fall, which did not support the need for higher root activity to correspond with extended leaf phenology. We found higher spring 15N uptake in non-native L. japonica compared to native L. sempervirens, although there was no difference in 15N uptake between Frangula and Rhamnus species. Our findings indicate the potential for fast-growing non-native Lonicera japonica and Frangula alnus to outcompete native counterparts through differences in biomass allocation, root turnover, and nitrogen uptake, however evidence that this is a general strategy of invader dominance is limited.

Show MeSH
Related in: MedlinePlus