Pathogen mortality of tropical tree seedlings: experimental studies of the effects of dispersal distance, seedling density, and light conditions

Augspurger, Carol K.; Kelly, Colleen K.

doi:10.1007/bf00396763

Cited by 507 publications

(482 citation statements)

References 16 publications

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“…Nee 2003;Purves & Pacala 2005;Volkov et al 2005), the empirical evidence for the importance of pathogens has been growing, and recent interest in this mechanism is underpinned by a long history of field study in tropical forests (e.g. Augspurger 1984aAugspurger ,b, 1990Augspurger & Kelly 1984;Dalling et al 1998).…”

Section: Introductionmentioning

confidence: 99%

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Pathogens, density dependence and the coexistence of tropical trees

2006

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There is increasing interest in the role played by density-dependent mortality from natural enemies, particularly plant pathogens, in promoting the coexistence and diversity of tropical trees. Here, we review four issues in the analysis of pathogen-induced density dependence that have been overlooked or inadequately addressed. First, the methodology for detecting density dependence must be robust to potential biases. Observational studies, in particular, require a careful analysis to avoid biases generated by measurement error, and existing studies could be criticized on these grounds. Experimental studies manipulating plant density and pathogen incidence will often be preferable, or should be run in parallel. Second, the form of density dependence is not well understood and, in particular, there are no data indicating whether pathogens cause compensating or overcompensating density responses. Owing to this, we argue that the potential for pathogen-induced density dependence to generate diversity-enhancing outcomes, such as the Janzen-Connell effect, remains uncertain, as coexistence is far more probable if density dependence is overcompensating. Third, there have been few studies examining the relative importance of intra-or interspecific density dependence resulting from pathogens (or, more widely, natural enemies). This is essentially equivalent to asking to what extent pathogens are host-specific. If pathogens are generalists, then mortality rates will respond to overall plant density, irrespective of plant species identity. This will weaken the intraspecific density dependence and reduce the diversity-promoting effects of pathogens. Finally, we highlight the need for studies that integrate observations and experiments on pathogens and density dependence into the whole life cycle of trees, because as yet it is not possible to be certain of the degree to which pathogens contribute to observed dynamics.

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Section: Introductionmentioning

confidence: 99%

“…Augspurger 1984aAugspurger ,b, 1990Augspurger & Kelly 1984;Dalling et al 1998;reviewed by Gilbert 2005). This body of work is extremely suggestive, but by no means conclusive.…”

Section: Introductionmentioning

confidence: 99%

Pathogens, density dependence and the coexistence of tropical trees

2006

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“…If effects of pathogens increase with plant density, pathogens have the potential to regulate host population size and alter spatial distributions (4,51). Several studies have demonstrated important density-dependent effects of disease in natural plant populations (18,21,55,75). Of course, plant survival, size, and growth rates also depend on plant density, and compensatory effects can alter the effect of disease on plant populations.…”

Section: Population Ecology and Geneticsmentioning

confidence: 99%

Disease in Natural Plant Populations, Communities, and Ecosystems: Insights into Ecological and Evolutionary Processes

Alexander

2010

Plant Disease

105

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Pathogens are associated with virtually all plant species, from a diverse array of habitats. Although we know the most about diseases of economically important plants, the goal of this article is to describe current work on host-pathogen interactions in natural or unmanaged systems outside of the crop field or forestry plantation. Agricultural scientists, of course, have contributed to this research. For example, disease resistance genes are often discovered as a result of surveys of wild relatives of crop plants, and it is well known that crop disease levels can be influenced by diseases in nearby weeds. Starting in the late 1970s, however, research on natural plant-pathogen interactions began to both increase and diversify, with an explicit goal of understanding the ecology and evolution of these interactions. This article will trace the history of this young discipline and provide highlights of ongoing research areas. I will focus on work by ecologists and evolutionary biologists that often is not published in plant pathology or forestry journals.A first step is to define a natural system as opposed to an agricultural or human-managed system. In contrast to most row crops, most natural populations occur in complex spatial arrangements with tens to hundreds of other species, are genetically diverse, and consist of plants of different ages and developmental stages. Seeds produced by a population in one year are the source of future generations at the site. Natural populations need not be pristine; as defined above, roadside weeds are as natural as prairie wildflowers. This natural versus agricultural dichotomy is also, of course, simplistic. Forest plantations and pasture landscapes have many natural attributes, and the degree of distinction between agricultural and natural ecosystems varies around the world.Although there have always been researchers intrigued by the role of pathogens in nature (58), publications in the 1970s and 1980s were influential in introducing the study of plant disease to ecologists and evolutionary biologists. For example, John Harper, a British biologist, published a landmark book in 1977 called Population Biology of Plants (61). This large tome (892 pages) encouraged ecologists to view plants not as vegetation, but as populations of individuals. One of his 17 chapters was titled "Pathogens" and emphasized the effect that disease could have on the structure and dynamics of plant populations and communities. Harper's book was followed a decade later by Jeremy Burdon's 1987 book Diseases and Plant Population Biology (30). Burdon expanded on the ecological consequences of disease and also emphasized genetic interactions between host and pathogen. Both Harper and Burdon emphasized the relevance of crop research and theories developed in an agricultural context, such as van der Plank's (101) work in epidemiology and Flor's gene-for-gene hypothesis (50). Interestingly, at the same time period, several plant pathologists were discussing disease in natural systems (130). Browning (29), in pa...

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“…A morfologia das sementes, bem como o tipo de agente dispersor, influencia no processo, na distância alcançada pelos diásporos e na eficiência da dispersão, visto que, quanto mais distante da fonte dispersora, maior a probabilidade de estabelecimento e a contribuição para a dinâmica sucessional ( VAN DER PIJL, 1982;AUGSPURGER;KELLY, 1984). Visto que sementes resultantes da dispersão de áreas afastadas podem contribuir para a riqueza de espécies e a variabilidade genética das populações presentes no local, enquanto a dispersão restrita e a escassez de indivíduos produtores restringem a diversidade da comunidade florestal (CAMPOS et al, 2009).…”

Section: Introductionunclassified

Chuva De Sementes Em Estádios Sucessionais De Floresta Estacional Semidecidual Em Viçosa-Mg

2015

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RESUMOOs objetivos deste estudo foram caracterizar e avaliar a dinâmica da chuva de sementes em dois estádios sucessionais de uma Floresta Estacional Semidecidual, no campus de Viçosa, MG (20°46’ S e 42°52’ W), da Universidade Federal de Viçosa. No estudo realizado entre o período de abril de 2007 e março de 2008, foram reconhecidos 84 taxa, sendo 41 espécies pertencentes a 25 famílias na floresta inicial e 24 espécies pertencentes a 13 famílias na floresta avançada, cuja forma de vida dominante foi arbórea e a síndrome de dispersão predominante, a zoocórica. A densidade média de sementes na floresta inicial foi de 637,5 sementes/ m2 e na avançada, de 124,6 sementes/m2. O índice de Sørensen de 55% indicou baixa similaridade florística entre as sementes das espécies encontradas na chuva de sementes dos dois trechos de florestas analisados.

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Pathogen mortality of tropical tree seedlings: experimental studies of the effects of dispersal distance, seedling density, and light conditions

Cited by 507 publications

References 16 publications

Pathogens, density dependence and the coexistence of tropical trees

Pathogens, density dependence and the coexistence of tropical trees

Disease in Natural Plant Populations, Communities, and Ecosystems: Insights into Ecological and Evolutionary Processes

Chuva De Sementes Em Estádios Sucessionais De Floresta Estacional Semidecidual Em Viçosa-Mg

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