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Mismatch in microbial food webs: predators but not prey perform better in their local biotic and abiotic conditions

View Article: PubMed Central - PubMed

ABSTRACT

Understanding how trophic levels respond to changes in abiotic and biotic conditions is key for predicting how food webs will react to environmental perturbations. Different trophic levels may respond disproportionately to change, with lower levels more likely to react faster, as they typically consist of smaller‐bodied species with higher reproductive rates. This response could cause a mismatch between trophic levels, in which predators and prey will respond differently to changing abiotic or biotic conditions. This mismatch between trophic levels could result in altered top‐down and bottom‐up control and changes in interaction strength. To determine the possibility of a mismatch, we conducted a reciprocal‐transplant experiment involving Sarracenia purpurea food webs consisting of bacterial communities as prey and a subset of six morphologically similar protozoans as predators. We used a factorial design with four temperatures, four bacteria and protozoan biogeographic origins, replicated four times. This design allowed us to determine how predator and prey dynamics were altered by abiotic (temperature) conditions and biotic (predators paired with prey from either their local or non‐local biogeographic origin) conditions. We found that prey reached higher densities in warmer temperature regardless of their temperature of origin. Conversely, predators achieved higher densities in the temperature condition and with the prey from their origin. These results confirm that predators perform better in abiotic and biotic conditions of their origin while their prey do not. This mismatch between trophic levels may be especially significant under climate change, potentially disrupting ecosystem functioning by disproportionately affecting top‐down and bottom‐up control.

No MeSH data available.


Related in: MedlinePlus

Predicted response in relative performance when species are ecologically nonspecialized versus specialized. The graphic shows the expected relationship between a measure of relative performance (e.g., growth rate) for populations that are ecologically nonspecialized (top row) or specialized (bottom row), to either abiotic (left column) or biotic (right column) conditions. The graphs represent populations tested under different conditions, with the second data point on each graph (in black) being the species in its local condition.
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ece32236-fig-0001: Predicted response in relative performance when species are ecologically nonspecialized versus specialized. The graphic shows the expected relationship between a measure of relative performance (e.g., growth rate) for populations that are ecologically nonspecialized (top row) or specialized (bottom row), to either abiotic (left column) or biotic (right column) conditions. The graphs represent populations tested under different conditions, with the second data point on each graph (in black) being the species in its local condition.

Mentions: As highlighted above, predictions are in general difficult to formulate because of the many factors that can affect interactions and growth rate within trophic levels. However, based on the general allometry relationship, we predict that there will be a mismatch between the two trophic levels. First, body‐size allometry between predators and prey shows that predators are typically larger bodied (Brose et al. 2006), which is clearly the case in our system; second, Fenchel's allometry demonstrates that larger organisms have a lower maximum rate of increase (Fenchel 1974); third, generation‐time allometry indicates that larger organisms have a longer generation time (Millar and Zammuto 1983). Consequently, larger‐bodied organisms of higher trophic levels should react slower to changing conditions than the smaller‐bodied organisms of lower trophic level. We thus hypothesize that there will be a mismatch between the two trophic levels. The faster‐growing lower trophic level should be better able to track environmental changes, and therefore be less ecologically specialized. Thus, they should perform well in both local and non‐local abiotic and biotic conditions. In contrast, the slower‐growing higher trophic level should be more ecologically specialized and thus perform better in local abiotic and biotic conditions (see Fig. 1). In accordance with our predictions, we will present evidence that the lower trophic levels did not perform better in the local abiotic or biotic conditions of their origin, but that the higher trophic levels performed better and that interaction strength was stronger in local abiotic conditions than in other conditions.


Mismatch in microbial food webs: predators but not prey perform better in their local biotic and abiotic conditions
Predicted response in relative performance when species are ecologically nonspecialized versus specialized. The graphic shows the expected relationship between a measure of relative performance (e.g., growth rate) for populations that are ecologically nonspecialized (top row) or specialized (bottom row), to either abiotic (left column) or biotic (right column) conditions. The graphs represent populations tested under different conditions, with the second data point on each graph (in black) being the species in its local condition.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4979714&req=5

ece32236-fig-0001: Predicted response in relative performance when species are ecologically nonspecialized versus specialized. The graphic shows the expected relationship between a measure of relative performance (e.g., growth rate) for populations that are ecologically nonspecialized (top row) or specialized (bottom row), to either abiotic (left column) or biotic (right column) conditions. The graphs represent populations tested under different conditions, with the second data point on each graph (in black) being the species in its local condition.
Mentions: As highlighted above, predictions are in general difficult to formulate because of the many factors that can affect interactions and growth rate within trophic levels. However, based on the general allometry relationship, we predict that there will be a mismatch between the two trophic levels. First, body‐size allometry between predators and prey shows that predators are typically larger bodied (Brose et al. 2006), which is clearly the case in our system; second, Fenchel's allometry demonstrates that larger organisms have a lower maximum rate of increase (Fenchel 1974); third, generation‐time allometry indicates that larger organisms have a longer generation time (Millar and Zammuto 1983). Consequently, larger‐bodied organisms of higher trophic levels should react slower to changing conditions than the smaller‐bodied organisms of lower trophic level. We thus hypothesize that there will be a mismatch between the two trophic levels. The faster‐growing lower trophic level should be better able to track environmental changes, and therefore be less ecologically specialized. Thus, they should perform well in both local and non‐local abiotic and biotic conditions. In contrast, the slower‐growing higher trophic level should be more ecologically specialized and thus perform better in local abiotic and biotic conditions (see Fig. 1). In accordance with our predictions, we will present evidence that the lower trophic levels did not perform better in the local abiotic or biotic conditions of their origin, but that the higher trophic levels performed better and that interaction strength was stronger in local abiotic conditions than in other conditions.

View Article: PubMed Central - PubMed

ABSTRACT

Understanding how trophic levels respond to changes in abiotic and biotic conditions is key for predicting how food webs will react to environmental perturbations. Different trophic levels may respond disproportionately to change, with lower levels more likely to react faster, as they typically consist of smaller‐bodied species with higher reproductive rates. This response could cause a mismatch between trophic levels, in which predators and prey will respond differently to changing abiotic or biotic conditions. This mismatch between trophic levels could result in altered top‐down and bottom‐up control and changes in interaction strength. To determine the possibility of a mismatch, we conducted a reciprocal‐transplant experiment involving Sarracenia purpurea food webs consisting of bacterial communities as prey and a subset of six morphologically similar protozoans as predators. We used a factorial design with four temperatures, four bacteria and protozoan biogeographic origins, replicated four times. This design allowed us to determine how predator and prey dynamics were altered by abiotic (temperature) conditions and biotic (predators paired with prey from either their local or non‐local biogeographic origin) conditions. We found that prey reached higher densities in warmer temperature regardless of their temperature of origin. Conversely, predators achieved higher densities in the temperature condition and with the prey from their origin. These results confirm that predators perform better in abiotic and biotic conditions of their origin while their prey do not. This mismatch between trophic levels may be especially significant under climate change, potentially disrupting ecosystem functioning by disproportionately affecting top‐down and bottom‐up control.

No MeSH data available.


Related in: MedlinePlus