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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 T treatment (Pm I, Pm IV and Pm III with interspecific interactions), lower pie charts are the dynamics in the FiT treatment (Pm I, Pm IV and Pm III without interspecific interactions).
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pone.0131625.g003: 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 T treatment (Pm I, Pm IV and Pm III with interspecific interactions), lower pie charts are the dynamics in the FiT treatment (Pm I, Pm IV and Pm III without interspecific interactions).

Mentions: In the treatments with three species, total numbers of adults (regardless of the species) were affected by time, the interaction between time and interspecific interactions treatment as well as the interaction between interspecific interactions treatment and temperature (respectively F2,24 = 6.88, p = 0.004, F2,24 = 4.73, p = 0.019 and F1,24 = 5.05, p = 0.034), with lower numbers of adults in the T treatment compared with the FiT treatment at fluctuating temperature at the end of the experiment (Fig 3). In the T treatment, more adults were found at the constant temperature compared with the fluctuating temperature (respectively 358 ± 43.2 and 232 ± 43.0 adults). Total abundances of juveniles (regardless of species) were affected by time, interspecific interactions treatment, temperature (respectively F2,24 = 17.71, p<0.001, F1,24 = 17.35, p<0.001 and F1,24 = 5.89, p = 0.023), the interaction between time and interspecific interactions treatment, and the interaction between time and temperature (respectively F2,24 = 14.95, p<0.001 and F2,24 = 8.46, p = 0.002). Abundances of juveniles differed between the T and FiT treatment after 14 days and 21 days, with very low numbers of juveniles in the T treatment. Only at day 14, numbers of juveniles were higher in the fluctuating temperature regime compared with the constant temperature (Fig 3). For the assemblage dynamics, no effect of temperature regime on the adult assemblages was found. There was an effect of time, interspecific interactions (T vs FiT) and the interaction of time and interspecific interactions (Table 4) on the adult assemblages. Differences in assemblage dynamics were found between the FiT and the T treatment at every time moment (Fig 3). SIMPER analysis showed that Pm I was the main responsible for the dissimilarity between these treatments. Pm I was less abundant in the T treatment than expected based on the FiT-treatments, in which Pm I became dominant after 14 days (Fig 3A and 3B), while Pm IV was the most abundant species in the T treatment after 7 and 14 days and Pm III after 21 days. Moreover, juvenile assemblage composition was also influenced by time, interspecific interactions, temperature, the interaction of time and interspecific interactions and the interaction of time and temperature (Table 4, Fig 3C and 3D).


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 T treatment (Pm I, Pm IV and Pm III with interspecific interactions), lower pie charts are the dynamics in the FiT treatment (Pm I, Pm IV and Pm III without interspecific interactions).
© Copyright Policy
Related In: Results  -  Collection

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

pone.0131625.g003: 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 T treatment (Pm I, Pm IV and Pm III with interspecific interactions), lower pie charts are the dynamics in the FiT treatment (Pm I, Pm IV and Pm III without interspecific interactions).
Mentions: In the treatments with three species, total numbers of adults (regardless of the species) were affected by time, the interaction between time and interspecific interactions treatment as well as the interaction between interspecific interactions treatment and temperature (respectively F2,24 = 6.88, p = 0.004, F2,24 = 4.73, p = 0.019 and F1,24 = 5.05, p = 0.034), with lower numbers of adults in the T treatment compared with the FiT treatment at fluctuating temperature at the end of the experiment (Fig 3). In the T treatment, more adults were found at the constant temperature compared with the fluctuating temperature (respectively 358 ± 43.2 and 232 ± 43.0 adults). Total abundances of juveniles (regardless of species) were affected by time, interspecific interactions treatment, temperature (respectively F2,24 = 17.71, p<0.001, F1,24 = 17.35, p<0.001 and F1,24 = 5.89, p = 0.023), the interaction between time and interspecific interactions treatment, and the interaction between time and temperature (respectively F2,24 = 14.95, p<0.001 and F2,24 = 8.46, p = 0.002). Abundances of juveniles differed between the T and FiT treatment after 14 days and 21 days, with very low numbers of juveniles in the T treatment. Only at day 14, numbers of juveniles were higher in the fluctuating temperature regime compared with the constant temperature (Fig 3). For the assemblage dynamics, no effect of temperature regime on the adult assemblages was found. There was an effect of time, interspecific interactions (T vs FiT) and the interaction of time and interspecific interactions (Table 4) on the adult assemblages. Differences in assemblage dynamics were found between the FiT and the T treatment at every time moment (Fig 3). SIMPER analysis showed that Pm I was the main responsible for the dissimilarity between these treatments. Pm I was less abundant in the T treatment than expected based on the FiT-treatments, in which Pm I became dominant after 14 days (Fig 3A and 3B), while Pm IV was the most abundant species in the T treatment after 7 and 14 days and Pm III after 21 days. Moreover, juvenile assemblage composition was also influenced by time, interspecific interactions, temperature, the interaction of time and interspecific interactions and the interaction of time and temperature (Table 4, Fig 3C and 3D).

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