Distance‐dependent effects of soil‐derived biota on seedling survival of the tropical tree legume <i>Ormosia semicastrata</i>

Li, Ruibo; Yu, Shixiao; Wang, Yongfan; Staehelin, Christian; Zang, Runguo

doi:10.1111/j.1654-1103.2009.01058.x

Cited by 19 publications

(22 citation statements)

References 37 publications

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“…1). Negative effects of seedling density on seedling survival have been reported in previous studies testing the Janzen–Connell hypothesis (Packer & Clay 2000; Bell, Freckleton & Lewis 2006; Li et al. 2009; Bagchi et al.…”

Section: Discussionmentioning

confidence: 72%

Analysis of a negative plant–soil feedback in a subtropical monsoon forest

Liu

Xie³

et al. 2012

Journal of Ecology

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Summary1. The Janzen-Connell hypothesis provides explanations for species coexistence and predicts that recruitment of tree juveniles is reduced by host-specific enemies, particularly soil biota. Previous studies, however, have not fully addressed the aspect of host specificity. Using a legume tree (Ormosia glaberrima) in a subtropical monsoon forest as a model, we experimentally investigated the mechanisms underlying a Janzen-Connell effect. 2. A negative plant-soil feedback was identified by a field census and confirmed by planting surface-sterilized seeds at different densities around focal trees. Fungicides were applied to test whether the effects were caused by fungi. In a growth-room inoculation experiment, effects of collected soil samples on seedling survival were examined and compared to soil samples treated with fungicides. Sequencing of the internal transcribed spacer region (ITS) sequence of the 28S ribosomal RNA gene was used for pathogen identification. The fungus causing seedling mortality was isolated and characterized by ITS rDNA sequencing and inoculation experiments. 3. A Janzen-Connell effect was identified at a field site, in which O. glaberrima was a locally common species. In situ treatments with fungicides and a corresponding growth-room simulation experiment showed that seedling survival depended on the distance to focal adult trees and that a fungal pathogen attacked seeds and seedlings. No negative plant-soil feedback was observed at another field site with a single O. glaberrima tree, indicating a locally rare species advantage. 4. The disease-inducing fungus was identified as Fusarium oxysporum. Inoculation experiments showed that the isolated fungus was pathogenic on O. glaberrima seedlings, but non-pathogenic on seedlings from other tree species co-occurring with O. glaberrima. Moreover, susceptibility of O. glaberrima depended on seed provenance (likely genotype). 5. Synthesis. We demonstrate that an observed negative plant-soil feedback on a locally common legume tree is caused by a host-specific pathogen. Our data fully support the criteria of spatially unequal pathogen distribution and host specificity proposed in the Janzen-Connell model. Taken the interaction between O. glaberrima and F. oxysporum as a paradigm, we suggest that host-specific pathogens, locally accumulated around parent trees, are important determinants of tree community structure.

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Section: Discussionmentioning

confidence: 72%

Analysis of a negative plant–soil feedback in a subtropical monsoon forest

Liu

Xie³

et al. 2012

Journal of Ecology

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“…One recent study also suggested that most of the 151 North-American forest tree species suffered from conspecific negative effects across multiple spatial scales . A typical element of the vast majority of these tests is the use of manipulative experiments involving the planting of seedlings or additions of seeds (Augspurger 1983b(Augspurger , 1984Bagchi et al 2010;Li et al 2009;Liu et al 2012b;Mangan et al 2010;McCarthy-Neumann and Kobe 2010a, b;Swamy and Terborgh 2010), or the adoption of demographic analyses of spatial and temporal patterns of observed tree growth and survival in long-term permanent forest plots (Comita et al 2010;Harms et al 2000;Hille Ris Lambers et al 2002;Johnson et al 2012;Peters 2003;Webb and Peart 1999;Wills et al 2006). A few studies have utilized naturally geminated seedlings to test density or distance dependence in the field (Augspurger 1983a;Bell et al 2006;Packer and Clay 2000;Pigot and Leather 2008;Reinhart and Clay 2009).…”

Section: Introductionmentioning

confidence: 99%

Soil-borne pathogens restrict the recruitment of a subtropical tree: a distance-dependent effect

Wang

Liu

et al. 2014

Oecologia

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The Janzen-Connell hypothesis suggests that density- and/or distance-dependent juvenile mortality driven by host-specific natural enemies can explain high species diversity in tropical forests. However, such density and distance effects may not occur simultaneously and may not be driven by the same mechanism. Also, reports of attempts to identify and quantify the differences between these processes in tropical forests are scarce. In a primary subtropical forest in China, we (1) experimentally examined the relative influence of the distance to parent trees vs. conspecific seedling density on mortality patterns in Engelhardia fenzelii, (2) tested the role of soil-borne pathogens in driving density- or distance-dependent processes that cause seedling mortality, and (3) inspected the susceptibilities of different tree species to soil biota of E. fenzelii and the effects of soil biota from different tree species on E. fenzelii. The results from these field experiments showed that distance- rather than density-dependent processes driven by soil pathogens strongly affect the seedling survival of this species in its first year. We also observed increased survival of a fungicide treatment for E. fenzelii seedlings in the parent soil but not for the seedlings of the other three species in the E. fenzelii parent soil, or for E. fenzelii seedlings in the parent soil of three other species. This study illustrates how the distance-dependent pattern of seedling recruitment for this species is driven by soil pathogens, a mechanism that likely restricts the dominance of this abundant species.

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“…Experimental studies have shown that soil microbial communities play a key role in causing negative density‐dependent effects (e.g., Packer and Clay , Klironomos , Li et al. ). Overstory trees can act as reservoirs of pathogens that impair seedling performance (Liang et al.…”

Section: Introductionmentioning

confidence: 99%

“…Repeated high seed input and hence seedling emergence in high densities over multiple fruiting events may also lead to high pathogen accumulation in soil near maternal trees (Augspurger , Packer and Clay ), which may thereby create a gradient in pathogen inoculum levels in relation to the distance from maternal trees (Augspurger and Kelly , Augspurger , Packer and Clay , Li et al. ). Such an accumulation of host‐specific pathogens under bats’ feeding roosts is less likely since their location may change frequently (Morrison , , Kunz ) and roosts are typically in plants of species different from the species whose fruits they are consuming (Janzen et al.…”

Section: Introductionmentioning

confidence: 99%

“…Some attempts to assess both density‐ and distance‐dependent effects simultaneously have been experimental (e.g., Augspurger and Kelly , Packer and Clay , Li et al. ). Although experimental studies generally allow more direct tests separating hypothesized effects compared to observational studies, experimental conditions may not closely mimic natural conditions (Packer and Clay ).…”

Section: Introductionmentioning

confidence: 99%

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Resolving the paradox of clumped seed dispersal: positive density and distance dependence in a bat‐dispersed species

Sugiyama

Comita

Masaki

et al. 2018

Ecology

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One of the hypothesized benefits of seed dispersal is to escape density- and distance-responsive, host-specific, natural enemies near maternal plants where conspecific seed and seedling densities are high. Such high conspecific neighbor densities typically result in lower offspring growth and survival (i.e., negative density-dependent effects), yet many dispersal modes result in clumped seed distributions. New World leaf-nosed bats transport fruits to their feeding roosts and deposit seeds, thereby creating high-density seed/seedling patches beneath feeding roosts in heterospecific trees away from maternal trees, which seemingly nullifies a key benefit of seed dispersal. Such dispersal may still be adaptive if negative density-dependent effects are reduced under feeding roosts or if the benefit of being dispersed away from maternal trees outweighs negative effects of conspecific seed/seedling density below roosts. We mapped the entire post-germination population of a bat-dispersed tree species Calophyllum longifolium (Calophyllaceae) in a 50-ha plot on Barro Colorado Island, Panama in each of three successive years. We tested two hypotheses: (1) distance-dependent effects are stronger than density-dependent effects on seedling performance because seedlings far from conspecific adults are more likely to escape natural enemies even when at high densities and (2) negative density-dependent effects will be reduced far from vs. near conspecific adults. Density and distance were naturally decoupled, as expected. However, in contrast to our expectation, we found positive density effects on seedling survival and density-dependent effects did not differ with distance from conspecific adults. Both density and distance had positive effects on seedling survival when considered together, while only year had a significant effect on seedling growth. Thus, both being dispersed under bat feeding roosts and escaping the vicinity of conspecific adults were beneficial for C. longifolium seedling survival, supporting the directed dispersal and escape hypotheses, respectively. Despite resulting in high densities of conspecific seedlings, favorable habitat under bat feeding roosts and lack of negative density-dependent effects appear to provide evolutionary advantages in C. longifolium.

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Distance‐dependent effects of soil‐derived biota on seedling survival of the tropical tree legume Ormosia semicastrata

Cited by 19 publications

References 37 publications

Analysis of a negative plant–soil feedback in a subtropical monsoon forest

Analysis of a negative plant–soil feedback in a subtropical monsoon forest

Soil-borne pathogens restrict the recruitment of a subtropical tree: a distance-dependent effect

Resolving the paradox of clumped seed dispersal: positive density and distance dependence in a bat‐dispersed species

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