The influence of spatial patterns of damping‐off disease and arbuscular mycorrhizal colonization on tree seedling establishment in Ghanaian tropical forest soil

Hood, Lorraine A.; Swaine, Michael; Mason, P.

doi:10.1111/j.0022-0477.2004.00917.x

Cited by 84 publications

(126 citation statements)

References 33 publications

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“…Moreover, fungal growth was not influenced by canopy cover (Fig. 3A) unlike other seed/seedling pathogens reported for which ''damping off '' effects are reduced by high light associated with gaps (Augspurger 1983, Hood et al 2004). Invertebrates may inadvertently facilitate spread and impact of this fungus on masting seed populations by creating entry points for infection.…”

Section: Seed Pathogensmentioning

confidence: 84%

Seed fate and seedling dynamics after masting in two African rain forest trees

Norghauer

Newbery

2011

Ecological Monographs

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Abstract. How the effects of biotic factors are moderated by abiotic factors, and their consequences for species interactions, is generally understudied in ecology. A key abiotic feature of forests is regular canopy disturbances that create temporary patches, or ''gaps,'' of above-average light availability. Co-occurring in lowland primary forest of Korup National Park (Cameroon), Microberlinia bisulcata and Tetraberlinia bifoliolata are locally dominant, ectomycorrhizal trees whose seeds share predator guilds in masting years. Here, we experimentally tested the impact of small mammal predators upon seedling abundance, growth, and survivorship. In 2007, we added a fixed density of seeds of each species to exclosures at 48 gap-understory locations across 82.5 ha within a large Microberlinia grove, and at 15 locations outside it.For both species, small mammals removed more seeds in gaps than in understory, whereas this was reversed for seeds killed by invertebrates. Nonetheless, Microberlinia lost twice as many seeds to small mammals, and more to invertebrates in exclosures, than Tetraberlinia, which was more prone to a pathogenic white fungus. After six weeks, both species had greater seedling establishment in gaps than understory, and in exclosures outside compared to exclosures inside the grove. In the subsequent two-year period, seedling growth and survivorship peaked in exclosures in gaps, but Microberlinia had more seedlings' stems clipped by animals than Tetraberlinia, and more than twice the percentage of leaf area damaged. Whereas Microberlinia seedling performance in gaps was inferior to Tetraberlinia inside the grove, outside it Microberlinia had reduced leaf damage, grew taller, and had many more leaves than Tetraberlinia.No evidence was found for ''apparent mutualism'' in the understory as seedling establishment of both species increased away from (.25 m) large stems of either species, pointing to ''apparent competition'' instead. In gaps, Microberlinia seedling establishment was lower near Tetraberlinia than conspecific adults because of context-dependent small mammal satiation. Stage-matrix analysis suggested that protecting Microberlinia from small mammals could increase its population growth rate by 0.06. In the light of prior research we conclude that small mammals and canopy gaps play an important role in promoting species coexistence in this forest, and that their strong interaction contributes to Microberlinia's currently very poor regeneration.

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Section: Seed Pathogensmentioning

confidence: 84%

Seed fate and seedling dynamics after masting in two African rain forest trees

Norghauer

Newbery

2011

Ecological Monographs

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“…In our study, understory juveniles encountered a much more diverse suite of fungal symbionts than did their mature counterparts. This canopy-understory disconnection is important because although several studies have shown distance-dependent pathogen or mutualist patterns for soilborne organisms (Augspurger 1984, Newbery et al 2000, Hood et al 2004, to our knowledge none have yet demonstrated that the canopy serves as a reservoir for symbionts. Density of airborne fungal spores is many times lower in the rainforest canopy than the understory , probably reflecting both reduced colonization of canopy leaves and environmental conditions hostile to spore production.…”

Section: Discussionmentioning

confidence: 99%

The Patchiness of Epifoliar Fungi in Tropical Forests: Host Range, Host Abundance, and Environment

Gilbert

Reynolds

Bethancourt

2007

Ecology

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Abstract. Fungal symbioses affect the diversity, dynamics, and spatial patterns of trees in tropical forests. Their ecological importance is partly driven by their inherent patchiness. We used epifoliar fungi, a guild of common, benign, obligate, fungal symbionts of plants, as a model system to evaluate the relative importance of host phylogeny, host relative abundance, and microclimate on the three-dimensional distribution of plant-fungus symbioses. In parallel studies in rainforests in Panama and Australia, most epifoliar fungi were able to colonize several plant lineages but showed significant host preferences within the local plant community. More closely related plant species were not more likely to share fungal symbionts. Instead, fungal species were more likely to be shared by more abundant hosts, which supported a greater number and diversity of fungi. Environmental conditions strongly affected spatial distributions, with sites in the dark understory 2.5-to fourfold more likely to have epifoliar fungi than in the exposed forest canopy. In the understory, fungal incidence increased with canopy openness. Canopy trees supported only a subset of the fungal symbionts found in the understory, suggesting that adult trees are not reservoirs of these fungal symbionts for understory juveniles.

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“…Such studies have generally found that seedling survival and growth are reduced in soil collected near conspecific adults due to an accumulation of soil-borne fungal pathogens (Augspurger 1984, Packer and Clay 2000, Hood et al 2004, Bell et al 2006. Differences in seedling performance when grown in soils near and far from a conspecific adult tree may be of no surprise considering the large amount of time in which fungal pathogens are allowed to accumulate.…”

Section: Scale and Ecological Implicationsmentioning

confidence: 99%

“…For example, negative plant-soil feedback is a frequency-dependent process, which can result from the accumulation of detrimental organisms (e.g., plant pathogens) that have species-specific effects in soils surrounding adult plants. This buildup, in turn, can decrease the growth and survival of conspecific juveniles rooted in close proximity to their adults (Augspurger 1984, Bever 1994, Mills and Bever 1998, Packer and Clay 2000, Klironomos 2002, Hood et al 2004, Bell et al 2006, Petermann et al 2008. Consequently, diversity is maintained because juveniles of other plant species (i.e., heterospecifics) that are relatively less affected by these pathogens have a competitive advantage at these sites (Connell et al 1971, Bever 1999.…”

Section: Introductionmentioning

confidence: 99%

Specificity between Neotropical tree seedlings and their fungal mutualists leads to plant–soil feedback

Mangan

Herre

Bever

2010

Ecology

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Abstract. A growing body of evidence obtained largely from temperate grassland studies suggests that feedbacks occurring between plants and their associated soil biota are important to plant community assemblage. However, few studies have examined the importance of soil organisms in driving plant-soil feedbacks in forested systems. In a tropical forest in central Panama, we examined whether interactions between tree seedlings and their associated arbuscular mycorrhizal fungi (AMF) lead to plant-soil feedback. Specifically, do tropical seedlings modify their own AMF communities in a manner that either favors or inhibits the next cohort of conspecific seedlings (i.e., positive or negative feedback, respectively)? Seedlings of two shade-tolerant tree species (Eugenia nesiotica, Virola surinamensis) and two pioneer tree species (Luehea seemannii, Apeiba aspera) were grown in pots containing identical AMF communities composed of equal amounts of inoculum of six co-occurring AMF species. The different AMF-host combinations were all exposed to two light levels. Under low light (2% PAR), only two of the six AMF species sporulated, and we found that host identity did not influence composition of AMF spore communities. However, relative abundances of three of the four AMF species that produced spores were influenced by host identity when grown under high light (20% PAR). Furthermore, spores of one of the AMF species, Glomus geosporum, were common in soils of Luehea and Eugenia but absent in soils of Apeiba and Virola. We then conducted a reciprocal experiment to test whether AMF communities previously modified by Luehea and Apeiba differentially affected the growth of conspecific and heterospecific seedlings. Luehea seedling growth did not differ between soils containing AMF communities modified by Luehea and Apeiba. However, Apeiba seedlings were significantly larger when grown with Apeiba-modified AMF communities, as compared to Apeiba seedlings grown with Luehea-modifed AMF communities. Our experiments suggest that interactions between tropical trees and their associated AMF are species-specific and that these interactions may shape both tree and AMF communities through plant-soil feedback.

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The influence of spatial patterns of damping‐off disease and arbuscular mycorrhizal colonization on tree seedling establishment in Ghanaian tropical forest soil

Cited by 84 publications

References 33 publications

Seed fate and seedling dynamics after masting in two African rain forest trees

Seed fate and seedling dynamics after masting in two African rain forest trees

The Patchiness of Epifoliar Fungi in Tropical Forests: Host Range, Host Abundance, and Environment

Specificity between Neotropical tree seedlings and their fungal mutualists leads to plant–soil feedback

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