Effects of stochastic herbivory events on population maintenance of an understorey palm species (<i>Geonoma schottiana</i>) in riparian tropical forest

Sampaio, Maurício Bonesso; Scariot, Aldicìr

doi:10.1017/s0266467409990599

Cited by 10 publications

(7 citation statements)

References 44 publications

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“…The stasis of later ontogenetic stages (immature and reproductive individuals; Figure ) was the demographic parameter with the greatest effect on λ in both E. edulis populations. This finding is in accordance with previous studies on long‐lived plant species such as palms (Franco & Silvertown, ; Kouassi, Barot, Gignoux, & Bi, ; Portela, Bruna, & Santos, ; Sampaio & Scariot, ). Similarly, the lower elasticity of sapling growth and fecundity explain why the negative contributions of these demographic processes did not significantly decrease the population growth rate at the altitudinal range limit.…”

Section: Discussionsupporting

confidence: 93%

“…In addi- The stasis of later ontogenetic stages (immature and reproductive individuals; Figure 3) was the demographic parameter with the greatest effect on λ in both E. edulis populations. This finding is in accordance with previous studies on long-lived plant species such as palms (Franco & Silvertown, 2004;Kouassi, Barot, Gignoux, & Bi, 2008;Portela, Bruna, & Santos, 2010;Sampaio & Scariot, 2010).…”

Section: Discussionmentioning

confidence: 99%

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Demographic processes limit upward altitudinal range expansion in a threatened tropical palm

Souza

Portela

Mattos

2018

Ecology and Evolution

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Understanding the factors that determine species’ range limits is a key issue in ecology, and is fundamental for biodiversity conservation under widespread global environmental change. Elucidating how altitudinal variation affects demographic processes may provide important clues for understanding the factors limiting current and future species distributions, yet population dynamics at range limits are still poorly understood. Here, we tested the hypothesis that lower abundance at a species’ upper altitudinal range limit is related to lower vital rates. We compared the dynamics of two populations of the tropical palm Euterpe edulis, located near and at the edge of its altitudinal limit of distribution in the Brazilian Atlantic Forest. Data from four annual censuses, from 2012 to 2015, were used. We used matrix population models to estimate asymptotic population growth rates and the elasticity values for the vital rates of the two populations of E. edulis. Life table response experiments were used to compare population performance by measuring the contribution of each vital rate to population growth rates. Population growth rates were not significantly different from one in either population, indicating that both populations were stable during the study period. However, the abundance of all ontogenetic stages was lower at the altitudinal range limit, which was related to decreases in some vital rates, especially fecundity. Additionally, there were higher elasticity values for the survival of immatures and reproductive individuals, compared to all other vital rates, in both populations. Synthesis. Our results show that even a small‐scale environmental variation near range limits is sufficient to drive changes in the demography of this threatened palm. A minor increase in elevation approaching the limit of altitudinal distribution may reduce environmental suitability and affect population vital rates, thus contributing to setting upper altitudinal range limits for plants.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Demographic processes limit upward altitudinal range expansion in a threatened tropical palm

Souza

Portela

Mattos

2018

Ecology and Evolution

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“…This is consistent with findings from other clonal palms, in which sprout production increased following disturbance (de Steven ) and for which clonal reproduction can buffer the effects of disturbance on population growth rates (Ticktin et al . ; Sampaio & Scariot ). In addition, we found increased growth of surviving ramets following fire, along with increased rates of flowering.…”

Section: Discussionmentioning

confidence: 99%

Resilience of palm populations to disturbance is determined by interactive effects of fire, herbivory and harvest

2015

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Summary 1.Little is known about the interactive effects of multiple forms of disturbance -natural or anthropogenic -on plant population dynamics. This limits our ability to understand the drivers of these dynamics and effectively manage plant populations in the face of changing disturbance regimes. 2. Fire, grazing and harvest of wild plants are three widespread, commonly co-occurring land management activities in the tropics that contribute to altered disturbance regimes. In this study, we investigate the effects of and interactions among these activities on mountain date palm (Phoenix loureiroi) populations in the Western Ghats, India with data from 14 palm populations, including over 2300 palm ramets monitored from 2009 to 2011. 3. We construct integral projection models (IPMs) of palm population dynamics based on the response of palm individuals to fire and varying intensities of grazing and leaf harvest and carry out Markov Chain Monte Carlo simulations to understand the implications of different scenarios of disturbance for population persistence. 4. We find that palm individuals and populations were resilient to low levels of fire, grazing and harvest. There are also important interactions among these forms of disturbance: intensities of harvest and grazing are highest in populations one to two years after fire, and the intensity of harvest is lower in heavily grazed populations. 5. These interactions mean that the combined effects of multiple forms of disturbance differ from what would be assumed from simply adding their separate effects. While simulations show that sustained high intensities of harvest and grazing would have severely negative consequences for palm populations, interactions between these two forms of disturbance prevent palm populations from actually experiencing such extreme conditions. On the other hand, because intensities of grazing and harvest both increase moderately following fire, their combined negative effects on population growth rates are exacerbated by fire. Thus, multiple, interacting disturbances determine the resilience of these palm populations and the sustainability of their management. 6. Synthesis. This study illustrates the importance of explicitly incorporating realistic interactions among multiple forms of disturbance when evaluating plant populations' resilience to changing disturbance regimes and the sustainability of plant harvest.

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“…(i) Productivity, with indices related to biomass and/or growth (e.g. Sampaio et al, 2008), percentage of plant damage (e.g. Chazdon, 1991), and density of individuals (e.g.…”

Section: Methodological Approachesmentioning

confidence: 99%

Disturbance and Resilience in Tropical American Palm Populations and Communities

et al. 2011

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We review resilience to natural and anthropogenic disturbance of palm populations and communities in tropical America. Response of palms to disturbance depends on their morphological traits, their reproductive strategies and the impacts of these traits and strategies on phenology and gene flow. Human impact induces changes in genetic structure, increasing endogamy and genetic drift in fragmented populations. Forest fragmentation and harvest of palm organs are well documented whereas effects of intermediate disturbance like selective logging, hunting or fire remain poorly known. We recommend emphasis on long-term experiments and on the use of mechanistic approaches in future research to facilitate integration of available data into a theoretical ecological framework.

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Effects of stochastic herbivory events on population maintenance of an understorey palm species (Geonoma schottiana) in riparian tropical forest

Cited by 10 publications

References 44 publications

Demographic processes limit upward altitudinal range expansion in a threatened tropical palm

Demographic processes limit upward altitudinal range expansion in a threatened tropical palm

Resilience of palm populations to disturbance is determined by interactive effects of fire, herbivory and harvest

Disturbance and Resilience in Tropical American Palm Populations and Communities

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