The role of spore size in the global pattern of co-occurrence among Selaginella species

Sofia Margaroni, Kurt B. Petersen, Roslyn Gleadow, Martin Burd

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Aim: Separation of regeneration niches may promote coexistence among closely related plant species, but there is little evidence that regeneration traits affect species ranges at broad geographical scales. We address patterns of co-occurrence within the genus Selaginella, an ancient lineage of free-sporing, heterosporous, vascular plants. Specifically, we ask whether differences between species in spore size are associated with the extent of overlap in their geographical ranges, a measure of opportunity for ecological interaction. Taxon: Selaginella (Selaginellaceae: Lycopodiales). Methods: We used quantile regression to examine the relationship of spore size ratios (pairwise ratios for megaspores and microspores of co-occurring species) to the area of range overlap and to latitude for a worldwide sample of 112 Selaginella species. Phylogenetically informed tests of statistical significance were used for each percentile relationship examined in the quantile regressions. Results: Large pairwise disparities in megaspore sizes were significantly associated with large range overlap. Disparities also tended to be larger at low latitudes. Microspore size differences, in contrast, were unrelated to shared range area or latitude. Main conclusion: Megaspore size appears to affect coexistence at a broad regional scale among Selaginella species, in at least some cases. The pattern is consistent with some degree of competitive structuring of size-related aspects of dispersal and establishment of propagules among some co-occurring species. Habitat complexity, such as open microsites within otherwise closed and shaded vegetation, seems likely to promote reproductive niche separation and may account for the latitudinal structure in Selaginella spore sizes.

Original languageEnglish
Pages (from-to)807-815
Number of pages9
JournalJournal of Biogeography
Volume46
Issue number4
DOIs
Publication statusPublished - 1 Jan 2019

Keywords

  • geographical range overlap
  • heterospory
  • interspecific competition
  • limiting similarity
  • megaspore
  • reproductive niche

Cite this

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title = "The role of spore size in the global pattern of co-occurrence among Selaginella species",
abstract = "Aim: Separation of regeneration niches may promote coexistence among closely related plant species, but there is little evidence that regeneration traits affect species ranges at broad geographical scales. We address patterns of co-occurrence within the genus Selaginella, an ancient lineage of free-sporing, heterosporous, vascular plants. Specifically, we ask whether differences between species in spore size are associated with the extent of overlap in their geographical ranges, a measure of opportunity for ecological interaction. Taxon: Selaginella (Selaginellaceae: Lycopodiales). Methods: We used quantile regression to examine the relationship of spore size ratios (pairwise ratios for megaspores and microspores of co-occurring species) to the area of range overlap and to latitude for a worldwide sample of 112 Selaginella species. Phylogenetically informed tests of statistical significance were used for each percentile relationship examined in the quantile regressions. Results: Large pairwise disparities in megaspore sizes were significantly associated with large range overlap. Disparities also tended to be larger at low latitudes. Microspore size differences, in contrast, were unrelated to shared range area or latitude. Main conclusion: Megaspore size appears to affect coexistence at a broad regional scale among Selaginella species, in at least some cases. The pattern is consistent with some degree of competitive structuring of size-related aspects of dispersal and establishment of propagules among some co-occurring species. Habitat complexity, such as open microsites within otherwise closed and shaded vegetation, seems likely to promote reproductive niche separation and may account for the latitudinal structure in Selaginella spore sizes.",
keywords = "geographical range overlap, heterospory, interspecific competition, limiting similarity, megaspore, reproductive niche",
author = "Sofia Margaroni and Petersen, {Kurt B.} and Roslyn Gleadow and Martin Burd",
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The role of spore size in the global pattern of co-occurrence among Selaginella species. / Margaroni, Sofia; Petersen, Kurt B.; Gleadow, Roslyn; Burd, Martin.

In: Journal of Biogeography, Vol. 46, No. 4, 01.01.2019, p. 807-815.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - The role of spore size in the global pattern of co-occurrence among Selaginella species

AU - Margaroni, Sofia

AU - Petersen, Kurt B.

AU - Gleadow, Roslyn

AU - Burd, Martin

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Aim: Separation of regeneration niches may promote coexistence among closely related plant species, but there is little evidence that regeneration traits affect species ranges at broad geographical scales. We address patterns of co-occurrence within the genus Selaginella, an ancient lineage of free-sporing, heterosporous, vascular plants. Specifically, we ask whether differences between species in spore size are associated with the extent of overlap in their geographical ranges, a measure of opportunity for ecological interaction. Taxon: Selaginella (Selaginellaceae: Lycopodiales). Methods: We used quantile regression to examine the relationship of spore size ratios (pairwise ratios for megaspores and microspores of co-occurring species) to the area of range overlap and to latitude for a worldwide sample of 112 Selaginella species. Phylogenetically informed tests of statistical significance were used for each percentile relationship examined in the quantile regressions. Results: Large pairwise disparities in megaspore sizes were significantly associated with large range overlap. Disparities also tended to be larger at low latitudes. Microspore size differences, in contrast, were unrelated to shared range area or latitude. Main conclusion: Megaspore size appears to affect coexistence at a broad regional scale among Selaginella species, in at least some cases. The pattern is consistent with some degree of competitive structuring of size-related aspects of dispersal and establishment of propagules among some co-occurring species. Habitat complexity, such as open microsites within otherwise closed and shaded vegetation, seems likely to promote reproductive niche separation and may account for the latitudinal structure in Selaginella spore sizes.

AB - Aim: Separation of regeneration niches may promote coexistence among closely related plant species, but there is little evidence that regeneration traits affect species ranges at broad geographical scales. We address patterns of co-occurrence within the genus Selaginella, an ancient lineage of free-sporing, heterosporous, vascular plants. Specifically, we ask whether differences between species in spore size are associated with the extent of overlap in their geographical ranges, a measure of opportunity for ecological interaction. Taxon: Selaginella (Selaginellaceae: Lycopodiales). Methods: We used quantile regression to examine the relationship of spore size ratios (pairwise ratios for megaspores and microspores of co-occurring species) to the area of range overlap and to latitude for a worldwide sample of 112 Selaginella species. Phylogenetically informed tests of statistical significance were used for each percentile relationship examined in the quantile regressions. Results: Large pairwise disparities in megaspore sizes were significantly associated with large range overlap. Disparities also tended to be larger at low latitudes. Microspore size differences, in contrast, were unrelated to shared range area or latitude. Main conclusion: Megaspore size appears to affect coexistence at a broad regional scale among Selaginella species, in at least some cases. The pattern is consistent with some degree of competitive structuring of size-related aspects of dispersal and establishment of propagules among some co-occurring species. Habitat complexity, such as open microsites within otherwise closed and shaded vegetation, seems likely to promote reproductive niche separation and may account for the latitudinal structure in Selaginella spore sizes.

KW - geographical range overlap

KW - heterospory

KW - interspecific competition

KW - limiting similarity

KW - megaspore

KW - reproductive niche

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U2 - 10.1111/jbi.13532

DO - 10.1111/jbi.13532

M3 - Article

VL - 46

SP - 807

EP - 815

JO - Journal of Biogeography

JF - Journal of Biogeography

SN - 0305-0270

IS - 4

ER -