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Plant ontogeny, spatial distance, and soil type influence patterns of relatedness in a common Amazonian tree.

Barbosa CE, Misiewicz TM, Fine PV, Costa FR - PLoS ONE (2013)

Bottom Line: By quantifying the patterns of relatedness among plants of different sizes, we inferred the ontogenetic stage in which SGS changes occurred, and compared these effects across soil types.Contrasting relatedness patterns between seedlings and larger individuals suggests a trade-off between the negative effects of being near closely-related adults (e.g. due to herbivore and pathogen attack) and the advantage of being in a site favorable to establishment.We also found that soil texture strongly influenced density-dependence patterns, as young seedlings in clay soils were more related to each other than were seedlings in bottomland sandy soils, suggesting that the mechanisms that create and maintain patterns of SGS within a population may interact with environmental heterogeneity.

View Article: PubMed Central - PubMed

Affiliation: Graduate Program in Ecology, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazonas, Brazil. cadubarbosa@gmail.com

ABSTRACT
The formation of spatial genetic structure (SGS) may originate from different patterns of seed deposition in the landscape, and is mostly determined by seed dispersal limitation. After dispersal, mechanisms such as filtering by environmental factors or attack by herbivores/pathogens throughout plant development stages, and potentially either disrupt or intensify SGS patterns. We investigated how the genotype of Protium subserratum (Burseraceae), a common tree species in the Ducke Reserve, Brazil, is distributed across the landscape. We used seven microsatellite markers to assess the SGS among plants at different life stages and in different environments. By quantifying the patterns of relatedness among plants of different sizes, we inferred the ontogenetic stage in which SGS changes occurred, and compared these effects across soil types. Relatedness among seedlings decreased when distance between seedlings increased, especially for the youngest seedlings. However, this trend was not continued by older plants, as relatedness values were higher among neighboring individuals of the juvenile and adult size class. Contrasting relatedness patterns between seedlings and larger individuals suggests a trade-off between the negative effects of being near closely-related adults (e.g. due to herbivore and pathogen attack) and the advantage of being in a site favorable to establishment. We also found that soil texture strongly influenced density-dependence patterns, as young seedlings in clay soils were more related to each other than were seedlings in bottomland sandy soils, suggesting that the mechanisms that create and maintain patterns of SGS within a population may interact with environmental heterogeneity.

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Spatial genetic structure at different life stages of Protium subserratum.Correlogram presenting SGS for P. subserratum seedlings of different height classes sampled at 14 plots at Ducke: (A) are seedlings up to 20 cm tall; (B) are seedlings from 21 to 40 cm tall, (C) are seedlings from 41 to 100 cm tall and (D) are juveniles and adults taller than 200 cm. The points indicate r-values with the error bars and the dashed lines are the upper and lower 95% CI limits around the mean value (r = 0) of the  distribution of a random distribution of alleles in space. The number of pairs compared at each distance class is reported in table 3.
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pone-0062639-g002: Spatial genetic structure at different life stages of Protium subserratum.Correlogram presenting SGS for P. subserratum seedlings of different height classes sampled at 14 plots at Ducke: (A) are seedlings up to 20 cm tall; (B) are seedlings from 21 to 40 cm tall, (C) are seedlings from 41 to 100 cm tall and (D) are juveniles and adults taller than 200 cm. The points indicate r-values with the error bars and the dashed lines are the upper and lower 95% CI limits around the mean value (r = 0) of the distribution of a random distribution of alleles in space. The number of pairs compared at each distance class is reported in table 3.

Mentions: The relatedness of 40 cm seedlings was greater than expected by chance throughout most of the plot, for either 50 m (Fig. 2) or 10 m (Fig. 3) distance interval classes, showing that the results are robust to the choice of distance interval. All four plant size classes had individuals more related to each other than expected by chance in the first distance class (0–50 m – Table 3). The relatedness among individuals decreases either within each plant size class as spatial distance increases (for all plant size classes) and among different plant size classes, as plants grow taller (r-values of first-year seedlings>young seedlings>saplings – Fig. 2). Juveniles and adults showed patterns of high relatedness among individuals in the first 100 meters (Fig. 2), although only results from the first distance class (0–50 m) can be considered robust due the small number of pairs compared, especially at the 51–100 m and 201–250 m distance classes. The multiclass test criteria (ω) performed separately for each plant size class allows an evaluation of the credibility of autocorrelations, and all four size classes exhibited significant SGS patterns in at least one distance class (Table 3).


Plant ontogeny, spatial distance, and soil type influence patterns of relatedness in a common Amazonian tree.

Barbosa CE, Misiewicz TM, Fine PV, Costa FR - PLoS ONE (2013)

Spatial genetic structure at different life stages of Protium subserratum.Correlogram presenting SGS for P. subserratum seedlings of different height classes sampled at 14 plots at Ducke: (A) are seedlings up to 20 cm tall; (B) are seedlings from 21 to 40 cm tall, (C) are seedlings from 41 to 100 cm tall and (D) are juveniles and adults taller than 200 cm. The points indicate r-values with the error bars and the dashed lines are the upper and lower 95% CI limits around the mean value (r = 0) of the  distribution of a random distribution of alleles in space. The number of pairs compared at each distance class is reported in table 3.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3646837&req=5

pone-0062639-g002: Spatial genetic structure at different life stages of Protium subserratum.Correlogram presenting SGS for P. subserratum seedlings of different height classes sampled at 14 plots at Ducke: (A) are seedlings up to 20 cm tall; (B) are seedlings from 21 to 40 cm tall, (C) are seedlings from 41 to 100 cm tall and (D) are juveniles and adults taller than 200 cm. The points indicate r-values with the error bars and the dashed lines are the upper and lower 95% CI limits around the mean value (r = 0) of the distribution of a random distribution of alleles in space. The number of pairs compared at each distance class is reported in table 3.
Mentions: The relatedness of 40 cm seedlings was greater than expected by chance throughout most of the plot, for either 50 m (Fig. 2) or 10 m (Fig. 3) distance interval classes, showing that the results are robust to the choice of distance interval. All four plant size classes had individuals more related to each other than expected by chance in the first distance class (0–50 m – Table 3). The relatedness among individuals decreases either within each plant size class as spatial distance increases (for all plant size classes) and among different plant size classes, as plants grow taller (r-values of first-year seedlings>young seedlings>saplings – Fig. 2). Juveniles and adults showed patterns of high relatedness among individuals in the first 100 meters (Fig. 2), although only results from the first distance class (0–50 m) can be considered robust due the small number of pairs compared, especially at the 51–100 m and 201–250 m distance classes. The multiclass test criteria (ω) performed separately for each plant size class allows an evaluation of the credibility of autocorrelations, and all four size classes exhibited significant SGS patterns in at least one distance class (Table 3).

Bottom Line: By quantifying the patterns of relatedness among plants of different sizes, we inferred the ontogenetic stage in which SGS changes occurred, and compared these effects across soil types.Contrasting relatedness patterns between seedlings and larger individuals suggests a trade-off between the negative effects of being near closely-related adults (e.g. due to herbivore and pathogen attack) and the advantage of being in a site favorable to establishment.We also found that soil texture strongly influenced density-dependence patterns, as young seedlings in clay soils were more related to each other than were seedlings in bottomland sandy soils, suggesting that the mechanisms that create and maintain patterns of SGS within a population may interact with environmental heterogeneity.

View Article: PubMed Central - PubMed

Affiliation: Graduate Program in Ecology, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazonas, Brazil. cadubarbosa@gmail.com

ABSTRACT
The formation of spatial genetic structure (SGS) may originate from different patterns of seed deposition in the landscape, and is mostly determined by seed dispersal limitation. After dispersal, mechanisms such as filtering by environmental factors or attack by herbivores/pathogens throughout plant development stages, and potentially either disrupt or intensify SGS patterns. We investigated how the genotype of Protium subserratum (Burseraceae), a common tree species in the Ducke Reserve, Brazil, is distributed across the landscape. We used seven microsatellite markers to assess the SGS among plants at different life stages and in different environments. By quantifying the patterns of relatedness among plants of different sizes, we inferred the ontogenetic stage in which SGS changes occurred, and compared these effects across soil types. Relatedness among seedlings decreased when distance between seedlings increased, especially for the youngest seedlings. However, this trend was not continued by older plants, as relatedness values were higher among neighboring individuals of the juvenile and adult size class. Contrasting relatedness patterns between seedlings and larger individuals suggests a trade-off between the negative effects of being near closely-related adults (e.g. due to herbivore and pathogen attack) and the advantage of being in a site favorable to establishment. We also found that soil texture strongly influenced density-dependence patterns, as young seedlings in clay soils were more related to each other than were seedlings in bottomland sandy soils, suggesting that the mechanisms that create and maintain patterns of SGS within a population may interact with environmental heterogeneity.

Show MeSH
Related in: MedlinePlus