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Daily Temperature Fluctuations Alter Interactions between Closely Related Species of Marine Nematodes.

De Meester N, Dos Santos GA, Rigaux A, Valdes Y, Derycke S, Moens T - PLoS ONE (2015)

Bottom Line: Our results showed that fluctuating temperature had minor or no effects on the population fitness of the three species in monocultures.Temperature regime did have a substantial effect on the interactions between the species.In addition, the strength of the interspecific interactions changed depending on the temperature regime in the three-species treatment.

View Article: PubMed Central - PubMed

Affiliation: Marine Biology Unit, Department of Biology, Ghent University, Gent, Belgium; Center for Molecular Phylogeny and Evolution, Ghent University, Gent, Belgium.

ABSTRACT
In addition to an increase in mean temperature, climate change models predict decreasing amplitudes of daily temperature fluctuations. In temperate regions, where daily and seasonal fluctuations are prominent, such decreases in daily temperature fluctuations can have a pronounced effect on the fitness of species and on the outcome of species interactions. In this study, the effect of a temperature regime with daily fluctuations versus a constant temperature on the fitness and interspecific interactions of three cryptic species of the marine nematode species complex of Litoditis marina (Pm I, Pm III and Pm IV) were investigated. In a lab experiment, different combinations of species (monospecific treatment: Pm I and Pm IV and Pm III alone; two-species treatment: Pm I + Pm IV; three-species treatment: Pm I + Pm IV + Pm III) were subjected to two different temperature regimes: one constant and one fluctuating temperature. Our results showed that fluctuating temperature had minor or no effects on the population fitness of the three species in monocultures. In contrast, interspecific interactions clearly influenced the fitness of all three species, both positively and negatively. Temperature regime did have a substantial effect on the interactions between the species. In the two-species treatment, temperature regime altered the interaction from a sort of mutualism to commensalism. In addition, the strength of the interspecific interactions changed depending on the temperature regime in the three-species treatment. This experiment confirms that interactions between the species can change depending on the abiotic environment; these results show that it is important to incorporate the effect of fluctuations on interspecific interactions to predict the effect of climate change on biodiversity.

No MeSH data available.


Related in: MedlinePlus

Total number of nematodes (adults: a + b, juveniles: c + d) over time in the different temperature treatments (constant temperature: a + c, fluctuating temperature: b + d) with assemblage dynamics at the different sampling times (three pie charts correspond with following time moments: 7, 14 and 21 days): upper pie charts for the D treatment (Pm I and Pm IV with interspecific interactions), lower pie charts are the dynamics in the FiD treatment (Pm I and Pm IV without interspecific interactions).
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pone.0131625.g002: Total number of nematodes (adults: a + b, juveniles: c + d) over time in the different temperature treatments (constant temperature: a + c, fluctuating temperature: b + d) with assemblage dynamics at the different sampling times (three pie charts correspond with following time moments: 7, 14 and 21 days): upper pie charts for the D treatment (Pm I and Pm IV with interspecific interactions), lower pie charts are the dynamics in the FiD treatment (Pm I and Pm IV without interspecific interactions).

Mentions: In the treatment with two species, total abundances of adults and juveniles (regardless of species) were affected by time and interspecific interactions treatment (respectively F2,24 = 24.30, p<0.001 and F1,24 = 50.03, p<0.001 for adults and F2,24 = 10.55, p<0.001 and F1,24 = 7.10, p = 0.014 for juveniles), but not by temperature. Lowest abundances of nematodes occurred after 7 days. They did not differ between 14 and 21 days. Much higher numbers of nematodes were observed in the D treatment compared with the FiD treatment (respectively 930 ± 171.6 vs. 97 ± 83.9 adults and 1459 ± 95.1 vs. 1074 ± 274.6 juveniles (Fig 2)). Comparing adult assemblage dynamics of Pm I and Pm IV between the D and FiD treatments showed significant effects of interspecific interactions, time and the interaction of interspecific interactions with temperature regime on the assemblage composition (Table 4). Pm I became dominant over Pm IV in the D treatment at the end of the experiment at a constant temperature, but the opposite was true at a fluctuating temperature. In the fictitious treatment (FiD), however, Pm IV was not dominant over Pm I at this fluctuating temperature (Fig 2A). For juvenile assemblage dynamics, only time and interspecific interactions were significant (Table 4, Fig 2B). A clear effect of interspecific interactions was shown, with Pm IV juveniles being dominant over Pm I in the D treatment compared with the FiD treatment independent of temperature regime.


Daily Temperature Fluctuations Alter Interactions between Closely Related Species of Marine Nematodes.

De Meester N, Dos Santos GA, Rigaux A, Valdes Y, Derycke S, Moens T - PLoS ONE (2015)

Total number of nematodes (adults: a + b, juveniles: c + d) over time in the different temperature treatments (constant temperature: a + c, fluctuating temperature: b + d) with assemblage dynamics at the different sampling times (three pie charts correspond with following time moments: 7, 14 and 21 days): upper pie charts for the D treatment (Pm I and Pm IV with interspecific interactions), lower pie charts are the dynamics in the FiD treatment (Pm I and Pm IV without interspecific interactions).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492701&req=5

pone.0131625.g002: Total number of nematodes (adults: a + b, juveniles: c + d) over time in the different temperature treatments (constant temperature: a + c, fluctuating temperature: b + d) with assemblage dynamics at the different sampling times (three pie charts correspond with following time moments: 7, 14 and 21 days): upper pie charts for the D treatment (Pm I and Pm IV with interspecific interactions), lower pie charts are the dynamics in the FiD treatment (Pm I and Pm IV without interspecific interactions).
Mentions: In the treatment with two species, total abundances of adults and juveniles (regardless of species) were affected by time and interspecific interactions treatment (respectively F2,24 = 24.30, p<0.001 and F1,24 = 50.03, p<0.001 for adults and F2,24 = 10.55, p<0.001 and F1,24 = 7.10, p = 0.014 for juveniles), but not by temperature. Lowest abundances of nematodes occurred after 7 days. They did not differ between 14 and 21 days. Much higher numbers of nematodes were observed in the D treatment compared with the FiD treatment (respectively 930 ± 171.6 vs. 97 ± 83.9 adults and 1459 ± 95.1 vs. 1074 ± 274.6 juveniles (Fig 2)). Comparing adult assemblage dynamics of Pm I and Pm IV between the D and FiD treatments showed significant effects of interspecific interactions, time and the interaction of interspecific interactions with temperature regime on the assemblage composition (Table 4). Pm I became dominant over Pm IV in the D treatment at the end of the experiment at a constant temperature, but the opposite was true at a fluctuating temperature. In the fictitious treatment (FiD), however, Pm IV was not dominant over Pm I at this fluctuating temperature (Fig 2A). For juvenile assemblage dynamics, only time and interspecific interactions were significant (Table 4, Fig 2B). A clear effect of interspecific interactions was shown, with Pm IV juveniles being dominant over Pm I in the D treatment compared with the FiD treatment independent of temperature regime.

Bottom Line: Our results showed that fluctuating temperature had minor or no effects on the population fitness of the three species in monocultures.Temperature regime did have a substantial effect on the interactions between the species.In addition, the strength of the interspecific interactions changed depending on the temperature regime in the three-species treatment.

View Article: PubMed Central - PubMed

Affiliation: Marine Biology Unit, Department of Biology, Ghent University, Gent, Belgium; Center for Molecular Phylogeny and Evolution, Ghent University, Gent, Belgium.

ABSTRACT
In addition to an increase in mean temperature, climate change models predict decreasing amplitudes of daily temperature fluctuations. In temperate regions, where daily and seasonal fluctuations are prominent, such decreases in daily temperature fluctuations can have a pronounced effect on the fitness of species and on the outcome of species interactions. In this study, the effect of a temperature regime with daily fluctuations versus a constant temperature on the fitness and interspecific interactions of three cryptic species of the marine nematode species complex of Litoditis marina (Pm I, Pm III and Pm IV) were investigated. In a lab experiment, different combinations of species (monospecific treatment: Pm I and Pm IV and Pm III alone; two-species treatment: Pm I + Pm IV; three-species treatment: Pm I + Pm IV + Pm III) were subjected to two different temperature regimes: one constant and one fluctuating temperature. Our results showed that fluctuating temperature had minor or no effects on the population fitness of the three species in monocultures. In contrast, interspecific interactions clearly influenced the fitness of all three species, both positively and negatively. Temperature regime did have a substantial effect on the interactions between the species. In the two-species treatment, temperature regime altered the interaction from a sort of mutualism to commensalism. In addition, the strength of the interspecific interactions changed depending on the temperature regime in the three-species treatment. This experiment confirms that interactions between the species can change depending on the abiotic environment; these results show that it is important to incorporate the effect of fluctuations on interspecific interactions to predict the effect of climate change on biodiversity.

No MeSH data available.


Related in: MedlinePlus