Search

Your search keyword '"Visser, Marco"' showing total 37 results
Start Over Author "Visser, Marco" Search Limiters Available in Library Collection
37 results on '"Visser, Marco"'

1. Latitudinal patterns in stabilizing density dependence of forest communities.

Author

Holík, Jan, Howe, Robert, Hubbell, Stephen, Itoh, Akira, Johnson, Daniel, Kenfack, David, Král, Kamil, Larson, Andrew, Lutz, James, Makana, Jean-Remy, Malhi, Yadvinder, McMahon, Sean, McShea, William, Mohamad, Mohizah, Nasardin, Musalmah, Nathalang, Anuttara, Norden, Natalia, Oliveira, Alexandre, Parmigiani, Renan, Perez, Rolando, Phillips, Richard, Pongpattananurak, Nantachai, Sun, I-Fang, Swanson, Mark, Tan, Sylvester, Thomas, Duncan, Thompson, Jill, Uriarte, Maria, Wolf, Amy, Yao, Tze, Zimmerman, Jess, Zuleta, Daniel, Hartig, Florian, Hülsmann, Lisa, Chisholm, Ryan, Comita, Liza, Visser, Marco, de Souza Leite, Melina, Aguilar, Salomon, Anderson-Teixeira, Kristina, Bourg, Norman, Brockelman, Warren, Bunyavejchewin, Sarayudh, Castaño, Nicolas, Chang-Yang, Chia-Hao, Chuyong, George, Clay, Keith, Davies, Stuart, Duque, Alvaro, Ediriweera, Sisira, Ewango, Corneille, and Gilbert, Gregory|Greg

Subjects
Seedlings, Tropical Climate, Forests, Trees, Biodiversity, Ecosystem
Abstract

Numerous studies have shown reduced performance in plants that are surrounded by neighbours of the same species1,2, a phenomenon known as conspecific negative density dependence (CNDD)3. A long-held ecological hypothesis posits that CNDD is more pronounced in tropical than in temperate forests4,5, which increases community stabilization, species coexistence and the diversity of local tree species6,7. Previous analyses supporting such a latitudinal gradient in CNDD8,9 have suffered from methodological limitations related to the use of static data10-12. Here we present a comprehensive assessment of latitudinal CNDD patterns using dynamic mortality data to estimate species-site-specific CNDD across 23 sites. Averaged across species, we found that stabilizing CNDD was present at all except one site, but that average stabilizing CNDD was not stronger toward the tropics. However, in tropical tree communities, rare and intermediate abundant species experienced stronger stabilizing CNDD than did common species. This pattern was absent in temperate forests, which suggests that CNDD influences species abundances more strongly in tropical forests than it does in temperate ones13. We also found that interspecific variation in CNDD, which might attenuate its stabilizing effect on species diversity14,15, was high but not significantly different across latitudes. Although the consequences of these patterns for latitudinal diversity gradients are difficult to evaluate, we speculate that a more effective regulation of population abundances could translate into greater stabilization of tropical tree communities and thus contribute to the high local diversity of tropical forests.

Published
2024

2. Latitudinal patterns in stabilizing density dependence of forest communities

Author

Hülsmann, Lisa, Chisholm, Ryan A., Comita, Liza, Visser, Marco D., de Souza Leite, Melina, Aguilar, Salomon, Anderson-Teixeira, Kristina J., Bourg, Norman A., Brockelman, Warren Y., Bunyavejchewin, Sarayudh, Castaño, Nicolas, Chang-Yang, Chia-Hao, Chuyong, George B., Clay, Keith, Davies, Stuart J., Duque, Alvaro, Ediriweera, Sisira, Ewango, Corneille, Gilbert, Gregory S., Holík, Jan, Howe, Robert W., Hubbell, Stephen P., Itoh, Akira, Johnson, Daniel J., Kenfack, David, Král, Kamil, Larson, Andrew J., Lutz, James A., Makana, Jean-Remy, Malhi, Yadvinder, McMahon, Sean M., McShea, William J., Mohamad, Mohizah, Nasardin, Musalmah, Nathalang, Anuttara, Norden, Natalia, Oliveira, Alexandre A., Parmigiani, Renan, Perez, Rolando, Phillips, Richard P., Pongpattananurak, Nantachai, Sun, I-Fang, Swanson, Mark E., Tan, Sylvester, Thomas, Duncan, Thompson, Jill, Uriarte, Maria, Wolf, Amy T., Yao, Tze Leong, Zimmerman, Jess K., Zuleta, Daniel, and Hartig, Florian

Published
2024
Full Text
View/download PDF

3. Liana optical traits increase tropical forest albedo and reduce ecosystem productivity

Author

Meunier, Félicien, Visser, Marco D, Shiklomanov, Alexey, Dietze, Michael C, Q., J Antonio Guzmán, Sanchez‐Azofeifa, G Arturo, De Deurwaerder, Hannes PT, Moorthy, Sruthi M Krishna, Schnitzer, Stefan A, Marvin, David C, Longo, Marcos, Liu, Chang, Broadbent, Eben N, Zambrano, Angelica M Almeyda, Muller‐Landau, Helene C, Detto, Matteo, and Verbeeck, Hans

Subjects
Biological Sciences, Ecology, Bayes Theorem, Carbon Cycle, Ecosystem, Forests, Tropical Climate, ecosystem demography model, forest albedo, forest energy balance, PROSPECT-5, radiative transfer models, structural parasitism, tropical lianas, Environmental Sciences, Biological sciences, Earth sciences, Environmental sciences
Abstract

Lianas are a key growth form in tropical forests. Their lack of self-supporting tissues and their vertical position on top of the canopy make them strong competitors of resources. A few pioneer studies have shown that liana optical traits differ on average from those of colocated trees. Those trait discrepancies were hypothesized to be responsible for the competitive advantage of lianas over trees. Yet, in the absence of reliable modelling tools, it is impossible to unravel their impact on the forest energy balance, light competition, and on the liana success in Neotropical forests. To bridge this gap, we performed a meta-analysis of the literature to gather all published liana leaf optical spectra, as well as all canopy spectra measured over different levels of liana infestation. We then used a Bayesian data assimilation framework applied to two radiative transfer models (RTMs) covering the leaf and canopy scales to derive tropical tree and liana trait distributions, which finally informed a full dynamic vegetation model. According to the RTMs inversion, lianas grew thinner, more horizontal leaves with lower pigment concentrations. Those traits made the lianas very efficient at light interception and significantly modified the forest energy balance and its carbon cycle. While forest albedo increased by 14% in the shortwave, light availability was reduced in the understorey (-30% of the PAR radiation) and soil temperature decreased by 0.5°C. Those liana-specific traits were also responsible for a significant reduction of tree (-19%) and ecosystem (-7%) gross primary productivity (GPP) while lianas benefited from them (their GPP increased by +27%). This study provides a novel mechanistic explanation to the increase in liana abundance, new evidence of the impact of lianas on forest functioning, and paves the way for the evaluation of the large-scale impacts of lianas on forest biogeochemical cycles.

Published
2022

5. Major axes of variation in tree demography across global forests

Author

Leite, Melina de Souza, McMahon, Sean M., Prado, Paulo Inácio, Davies, Stuart J., Oliveira, Alexandre Adalardo de, De Deurwaerder, Hannes P., Aguilar, Salomón, Anderson‐Teixeira, Kristina J., Aqilah, Nurfarah, Bourg, Norman A., Brockelman, Warren Y., Castaño, Nicolas, Chang‐Yang, Chia‐Hao, Chen, Yu‐Yun, Chuyong, George, Clay, Keith, Duque, Álvaro, Ediriweera, Sisira, Ewango, Corneille E.N., Gilbert, Gregory, Gunatilleke, I.A.U.N., Gunatilleke, C.V.S., Howe, Robert, Huasco, Walter Huaraca, Itoh, Akira, Johnson, Daniel J., Kenfack, David, Král, Kamil, Leong, Yao Tze, Lutz, James A., Makana, Jean‐Remy, Malhi, Yadvinder, McShea, William J., Mohamad, Mohizah, Nasardin, Musalmah, Nathalang, Anuttara, Parker, Geoffrey, Parmigiani, Renan, Pérez, Rolando, Phillips, Richard P., Šamonil, Pavel, Sun, I‐Fang, Tan, Sylvester, Thomas, Duncan, Thompson, Jill, Uriarte, María, Wolf, Amy, Zimmerman, Jess, Zuleta, Daniel, Visser, Marco D., Hülsmann, Lisa, Leite, Melina de Souza, McMahon, Sean M., Prado, Paulo Inácio, Davies, Stuart J., Oliveira, Alexandre Adalardo de, De Deurwaerder, Hannes P., Aguilar, Salomón, Anderson‐Teixeira, Kristina J., Aqilah, Nurfarah, Bourg, Norman A., Brockelman, Warren Y., Castaño, Nicolas, Chang‐Yang, Chia‐Hao, Chen, Yu‐Yun, Chuyong, George, Clay, Keith, Duque, Álvaro, Ediriweera, Sisira, Ewango, Corneille E.N., Gilbert, Gregory, Gunatilleke, I.A.U.N., Gunatilleke, C.V.S., Howe, Robert, Huasco, Walter Huaraca, Itoh, Akira, Johnson, Daniel J., Kenfack, David, Král, Kamil, Leong, Yao Tze, Lutz, James A., Makana, Jean‐Remy, Malhi, Yadvinder, McShea, William J., Mohamad, Mohizah, Nasardin, Musalmah, Nathalang, Anuttara, Parker, Geoffrey, Parmigiani, Renan, Pérez, Rolando, Phillips, Richard P., Šamonil, Pavel, Sun, I‐Fang, Tan, Sylvester, Thomas, Duncan, Thompson, Jill, Uriarte, María, Wolf, Amy, Zimmerman, Jess, Zuleta, Daniel, Visser, Marco D., and Hülsmann, Lisa

Abstract

The future trajectory of global forests is closely intertwined with tree demography, and a major fundamental goal in ecology is to understand the key mechanisms governing spatio-temporal patterns in tree population dynamics. While previous research has made substantial progress in identifying the mechanisms individually, their relative importance among forests remains unclear mainly due to practical limitations. One approach to overcome these limitations is to group mechanisms according to their shared effects on the variability of tree vital rates and quantify patterns therein. We developed a conceptual and statistical framework (variance partitioning of Bayesian multilevel models) that attributes the variability in tree growth, mortality, and recruitment to variation in species, space, and time, and their interactions – categories we refer to as organising principles (OPs). We applied the framework to data from 21 forest plots covering more than 2.9 million trees of approximately 6500 species. We found that differences among species, the species OP, proved a major source of variability in tree vital rates, explaining 28–33% of demographic variance alone, and 14–17% in interaction with space, totalling 40–43%. Our results support the hypothesis that the range of vital rates is similar across global forests. However, the average variability among species declined with species richness, indicating that diverse forests featured smaller interspecific differences in vital rates. Moreover, decomposing the variance in vital rates into the proposed OPs showed the importance of unexplained variability, which includes individual variation, in tree demography. A focus on how demographic variance is organized in forests can facilitate the construction of more targeted models with clearer expectations of which covariates might drive a vital rate. This study therefore highlights the most promising avenues for future research, both in terms of understanding the relative contribut

Published
2024

11. Closing the gap in the Janzen–Connell hypothesis: What determines pathogen diversity?

Author

Bruijning, Marjolein, Metcalf, C. Jessica E., and Visser, Marco D.

Subjects
BIOTIC communities, TROPICAL forests, PATHOGENIC microorganisms, FOREST biodiversity, HYPOTHESIS
Abstract

The high tree diversity in tropical forests has long been a puzzle to ecologists. In the 1970s, Janzen and Connell proposed that tree species (hosts) coexist due to the stabilizing actions of specialized enemies. This Janzen–Connell hypothesis was subsequently supported by theoretical studies. Yet, such studies have taken the presence of specialized pathogens for granted, overlooking that pathogen coexistence also requires an explanation. Moreover, stable ecological coexistence does not necessarily imply evolutionary stability. What are the conditions that allow Janzen–Connell effects to evolve? We link theory from community ecology, evolutionary biology and epidemiology to tackle this question, structuring our approach around five theoretical frameworks. Phenomenological Lotka–Volterra competition models provide the most basic framework, which can be restructured to include (single‐ or multi‐)pathogen dynamics. This ecological foundation can be extended to include pathogen evolution. Hosts, of course, may also evolve, and we introduce a coevolutionary model, showing that host–pathogen coevolution can lead to highly diverse systems. Our work unpacks the assumptions underpinning Janzen–Connell and places theoretical bounds on pathogen and host ecology and evolution. The five theoretical frameworks taken together provide a stronger theoretical basis for Janzen–Connell, delivering a wider lens that can yield important insights into the maintenance of diversity in these increasingly threatened systems. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

14. Results of a small terrestrial mammal survey in the remote Boé region of Guinea‐Bissau, with discovery of two new shrew records for the country.

Author

Westra, Sil A., Mol, Roy R., Desjardins, Rebecca B., Visser, Marco D., Baele, Amber V. M. P. C., and van Montfort, Dorien

Subjects
SHREWS, SOUND recordings, SPECIES diversity, MAMMALS, MAMMAL diversity, HABITATS
Abstract

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2022
Full Text
View/download PDF

15. Local canopy disturbance as an explanation for long‐term increases in liana abundance

Author

Schnitzer, Stefan A., primary, DeFilippis, David M., additional, Visser, Marco, additional, Estrada‐Villegas, Sergio, additional, Rivera‐Camaña, Rigoberto, additional, Bernal, Boris, additional, Peréz, Salomé, additional, Valdéz, Abelino, additional, Valdéz, Seberino, additional, Aguilar, Antonio, additional, Dalling, James W., additional, Broadbent, Eben N., additional, Almeyda Zambrano, Angelica M., additional, Hubbell, Stephen P., additional, and Garcia‐Leon, Maria, additional

Published
2021
Full Text
View/download PDF

17. ForestGEO: understanding forest diversity and dynamics through a global observatory network

Author

Davies, Stuart J., Abiem, Iveren, Abu Salim, Kamariah, Aguilar, Salomón, Allen, David, Alonso, Alfonso, Anderson-Teixeira, Kristina, Andrade, Ana, Arellano, Gabriel, Ashton, Peter S., Baker, Patrick J., Baker, Matthew E., Baltzer, Jennifer L., Basset, Yves, Bissiengou, Pulchérie, Bohlman, Stephanie, Bourg, Norman A., Brockelman, Warren Y., Bunyavejchewin, Sarayudh, Burslem, David F.R.P., Cao, Min, Cárdenas, Dairon, Chang, Li-Wan, Chang-Yang, Chia-Hao, Chao, Kuo-Jung, Chao, Wei-Chun, Chapman, Hazel, Chen, Yu-Yun, Chisholm, Ryan A., Chu, Chengjin, Chuyong, George, Clay, Keith, Comita, Liza S., Condit, Richard, Cordell, Susan, Dattaraja, Handanakere S., de Oliveira, Alexandre Adalardo, den Ouden, Jan, Detto, Matteo, Dick, Christopher, Du, Xiaojun, Duque, Álvaro, Ediriweera, Sisira, Ellis, Erle C., Engone Obiang, Nestor Laurier, Esufali, Shameema, Ewango, Corneille E.N., Fernando, Edwino S., Filip, Jonah, Fischer, Gunter A., Foster, Robin, Giambelluca, Thomas, Giardina, Christian, Gilbert, Gregory S., Gonzalez-Akre, Erika, Gunatilleke, I.A.U.N., Gunatilleke, C.V.S., Hao, Zhanqing, Hau, Billy C.H., He, Fangliang, Ni, Hongwei, Howe, Robert W., Hubbell, Stephen P., Huth, Andreas, Inman-Narahari, Faith, Itoh, Akira, Janík, David, Jansen, Patrick A., Jiang, Mingxi, Johnson, Daniel J., Jones, F. Andrew, Kanzaki, Mamoru, Kenfack, David, Kiratiprayoon, Somboon, Král, Kamil, Krizel, Lauren, Lao, Suzanne, Larson, Andrew J., Li, Yide, Li, Xiankun, Litton, Creighton M., Liu, Yu, Liu, Shirong, Lum, Shawn K.Y., Luskin, Matthew S., Lutz, James A., Luu, Hong Truong, Ma, Keping, Makana, Jean-Remy, Malhi, Yadvinder, Martin, Adam, McCarthy, Caly, McMahon, Sean M., McShea, William J., Memiaghe, Hervé, Mi, Xiangcheng, Mitre, David, Mohamad, Mohizah, Monks, Logan, Muller-Landau, Helene C., Musili, Paul M., Myers, Jonathan A., Nathalang, Anuttara, Ngo, Kang Min, Norden, Natalia, Novotny, Vojtech, O'Brien, Michael J., Orwig, David, Ostertag, Rebecca, Papathanassiou, Konstantinos, Parker, Geoffrey G., Pérez, Rolando, Perfecto, Ivette, Phillips, Richard P., Pongpattananurak, Nantachai, Pretzsch, Hans, Ren, Haibo, Reynolds, Glen, Rodriguez, Lillian J., Russo, Sabrina E., Sack, Lawren, Sang, Weiguo, Shue, Jessica, Singh, Anudeep, Song, Guo-Zhang M., Sukumar, Raman, Sun, I-Fang, Suresh, Hebbalalu S., Swenson, Nathan G., Tan, Sylvester, Thomas, Sean C., Thomas, Duncan, Thompson, Jill, Turner, Benjamin L., Uowolo, Amanda, Uriarte, María, Valencia, Renato, Vandermeer, John, Vicentini, Alberto, Visser, Marco, Vrska, Tomas, Wang, Xugao, Wang, Xihua, Weiblen, George D., Whitfeld, Timothy J.S., Wolf, Amy, Wright, S. Joseph, Xu, Han, Yao, Tze Leong, Yap, Sandra L., Ye, Wanhui, Yu, Mingjian, Zhang, Minhua, Zhu, Daoguang, Zhu, Li, Zimmerman, Jess K., Zuleta, Daniel, Davies, Stuart J., Abiem, Iveren, Abu Salim, Kamariah, Aguilar, Salomón, Allen, David, Alonso, Alfonso, Anderson-Teixeira, Kristina, Andrade, Ana, Arellano, Gabriel, Ashton, Peter S., Baker, Patrick J., Baker, Matthew E., Baltzer, Jennifer L., Basset, Yves, Bissiengou, Pulchérie, Bohlman, Stephanie, Bourg, Norman A., Brockelman, Warren Y., Bunyavejchewin, Sarayudh, Burslem, David F.R.P., Cao, Min, Cárdenas, Dairon, Chang, Li-Wan, Chang-Yang, Chia-Hao, Chao, Kuo-Jung, Chao, Wei-Chun, Chapman, Hazel, Chen, Yu-Yun, Chisholm, Ryan A., Chu, Chengjin, Chuyong, George, Clay, Keith, Comita, Liza S., Condit, Richard, Cordell, Susan, Dattaraja, Handanakere S., de Oliveira, Alexandre Adalardo, den Ouden, Jan, Detto, Matteo, Dick, Christopher, Du, Xiaojun, Duque, Álvaro, Ediriweera, Sisira, Ellis, Erle C., Engone Obiang, Nestor Laurier, Esufali, Shameema, Ewango, Corneille E.N., Fernando, Edwino S., Filip, Jonah, Fischer, Gunter A., Foster, Robin, Giambelluca, Thomas, Giardina, Christian, Gilbert, Gregory S., Gonzalez-Akre, Erika, Gunatilleke, I.A.U.N., Gunatilleke, C.V.S., Hao, Zhanqing, Hau, Billy C.H., He, Fangliang, Ni, Hongwei, Howe, Robert W., Hubbell, Stephen P., Huth, Andreas, Inman-Narahari, Faith, Itoh, Akira, Janík, David, Jansen, Patrick A., Jiang, Mingxi, Johnson, Daniel J., Jones, F. Andrew, Kanzaki, Mamoru, Kenfack, David, Kiratiprayoon, Somboon, Král, Kamil, Krizel, Lauren, Lao, Suzanne, Larson, Andrew J., Li, Yide, Li, Xiankun, Litton, Creighton M., Liu, Yu, Liu, Shirong, Lum, Shawn K.Y., Luskin, Matthew S., Lutz, James A., Luu, Hong Truong, Ma, Keping, Makana, Jean-Remy, Malhi, Yadvinder, Martin, Adam, McCarthy, Caly, McMahon, Sean M., McShea, William J., Memiaghe, Hervé, Mi, Xiangcheng, Mitre, David, Mohamad, Mohizah, Monks, Logan, Muller-Landau, Helene C., Musili, Paul M., Myers, Jonathan A., Nathalang, Anuttara, Ngo, Kang Min, Norden, Natalia, Novotny, Vojtech, O'Brien, Michael J., Orwig, David, Ostertag, Rebecca, Papathanassiou, Konstantinos, Parker, Geoffrey G., Pérez, Rolando, Perfecto, Ivette, Phillips, Richard P., Pongpattananurak, Nantachai, Pretzsch, Hans, Ren, Haibo, Reynolds, Glen, Rodriguez, Lillian J., Russo, Sabrina E., Sack, Lawren, Sang, Weiguo, Shue, Jessica, Singh, Anudeep, Song, Guo-Zhang M., Sukumar, Raman, Sun, I-Fang, Suresh, Hebbalalu S., Swenson, Nathan G., Tan, Sylvester, Thomas, Sean C., Thomas, Duncan, Thompson, Jill, Turner, Benjamin L., Uowolo, Amanda, Uriarte, María, Valencia, Renato, Vandermeer, John, Vicentini, Alberto, Visser, Marco, Vrska, Tomas, Wang, Xugao, Wang, Xihua, Weiblen, George D., Whitfeld, Timothy J.S., Wolf, Amy, Wright, S. Joseph, Xu, Han, Yao, Tze Leong, Yap, Sandra L., Ye, Wanhui, Yu, Mingjian, Zhang, Minhua, Zhu, Daoguang, Zhu, Li, Zimmerman, Jess K., and Zuleta, Daniel

Abstract

ForestGEO is a network of scientists and long-term forest dynamics plots (FDPs) spanning the Earth's major forest types. ForestGEO's mission is to advance understanding of the diversity and dynamics of forests and to strengthen global capacity for forest science research. ForestGEO is unique among forest plot networks in its large-scale plot dimensions, censusing of all stems ≥1 cm in diameter, inclusion of tropical, temperate and boreal forests, and investigation of additional biotic (e.g., arthropods) and abiotic (e.g., soils) drivers, which together provide a holistic view of forest functioning. The 71 FDPs in 27 countries include approximately 7.33 million living trees and about 12,000 species, representing 20% of the world's known tree diversity. With >1300 published papers, ForestGEO researchers have made significant contributions in two fundamental areas: species coexistence and diversity, and ecosystem functioning. Specifically, defining the major biotic and abiotic controls on the distribution and coexistence of species and functional types and on variation in species' demography has led to improved understanding of how the multiple dimensions of forest diversity are structured across space and time and how this diversity relates to the processes controlling the role of forests in the Earth system. Nevertheless, knowledge gaps remain that impede our ability to predict how forest diversity and function will respond to climate change and other stressors. Meeting these global research challenges requires major advances in standardizing taxonomy of tropical species, resolving the main drivers of forest dynamics, and integrating plot-based ground and remote sensing observations to scale up estimates of forest diversity and function, coupled with improved predictive models. However, they cannot be met without greater financial commitment to sustain the long-term research of ForestGEO and other forest plot networks, greatly expanded scientific capacity across the

Published
2021

21. Signs of stabilisation and stable coexistence

Author

Broekman, M.J.E., Muller-Landau, Helene C., Visser, Marco D., Jongejans, E., Wright, S., de Kroon, H., Broekman, M.J.E., Muller-Landau, Helene C., Visser, Marco D., Jongejans, E., Wright, S., and de Kroon, H.

Abstract

Contains fulltext : 207221.pdf (Publisher’s version ) (Open Access)

Published
2019

28. How do lianas and vines influence competitive differences and niche differences among tree species? Concepts and a case study in a tropical forest.

Author

Godoy, Oscar, Muller‐Landau, Helene C., and Visser, Marco D.

Subjects
TREES, TROPICAL forests, LIANAS, CLIMBING plants, HOST-parasite relationships
Abstract

Copyright of Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2019
Full Text
View/download PDF

29. Quantifying seed dispersal kernels from truncated seed-tracking data

Author

Hirsch, Ben T., Visser, Marco D., Kays, Roland, and Jansen, Patrick A.

Subjects
RECRUITMENT, SHADOWS, CONSEQUENCES, long-distance dispersal, TROPICAL FORESTS, RAIN-FOREST, SPATIAL-PATTERNS, seed dispersal, thread tag, kernel, DEPENDENCE, censored tail reconstruction, PLANT-POPULATIONS, WIND DISPERSAL, seed tracking, BEHAVIOR
Abstract

1. Seed dispersal is a key biological process that remains poorly documented because dispersing seeds are notoriously hard to track. While long-distance dispersal is thought to be particularly important, seed-tracking studies typically yield incomplete data sets that are biased against long-distance movements. 2. We evaluate an analytical procedure developed by Jansen, Bongers & Hemerik (2004) to infer the tail of a seed dispersal kernel from incomplete frequency distributions of dispersal distances obtained by tracking seeds. This censored tail reconstruction (CTR) method treats dispersal distances as waiting times in a survival analysis and censors nonretrieved seeds according to how far they can reliably be tracked. We tested whether CTR can provide unbiased estimates of long-distance movements which typically cannot be tracked with traditional field methods. 3. We used a complete frequency distribution of primary seed dispersal distances of the palm Astrocaryum standleyanum, obtained with telemetric thread tags that allow tracking seeds regardless of the distance moved. We truncated and resampled the data set at various distances, fitted kernel functions on CTR estimates of dispersal distance and determined how well this function approximated the true dispersal kernel. 4. Censored tail reconstruction with truncated data approximated the true dispersal kernel remarkably well but only when the best-fitting function (lognormal) was used. We were able to select the correct function and derive an accurate estimate of the seed dispersal kernel even after censoring 5060% of the dispersal events. However, CTR results were substantially biased if 5% or more of seeds within the search radius were overlooked by field observers and erroneously censored. Similar results were obtained using additional simulated dispersal kernels. 5. Our study suggests that the CTR method can accurately estimate the dispersal kernel from truncated seed-tracking data if the kernel is a simple decay function. This method will improve our understanding of the spatial patterns of seed movement and should replace the usual practice of omitting nonretrieved seeds from analyses in seed-tracking studies.

Published
2012

30. Tri-trophic interactions affect density dependence of seed fate in a tropical forest palm

Author

Visser, Marco D., Muller-Landau, Helene C., Wright, S. Joseph, Rutten, Gemma, and Jansen, Patrick A.

Subjects
tropical forest, PLANT DIVERSITY, NEOTROPICAL TREE, PREDATION, species diversity, species coexistence, fungi, SPECIES-DIVERSITY, food and beverages, RAIN-FOREST, PARENT PALM, BRUCHID BEETLES, JANZEN-CONNELL MODEL, trophic cascade, specialization, enemies hypothesis, seed predation, negative density dependence, DISPERSAL, Attalea butyracea, BARRO-COLORADO ISLAND, Barro Colorado Island
Abstract

Natural enemies, especially host-specific enemies, are hypothesised to facilitate the coexistence of plant species by disproportionately inflicting more damage at increasing host abundance. However, few studies have assessed such Janzen-Connell mechanisms on a scale relevant for coexistence and no study has evaluated potential top-down influences on the specialized pests. We quantified seed predation by specialist invertebrates and generalist vertebrates, as well as larval predation on these invertebrates, for the Neotropical palm Attalea butyracea across ten 4-ha plots spanning 20-fold variation in palm density. As palm density increased, seed attack by bruchid beetles increased, whereas seed predation by rodents held constant. But because rodent predation on bruchid larvae increased disproportionately with increasing palm density, bruchid emergence rates and total seed predation by rodents and bruchids combined were both density-independent. Our results demonstrate that top-down effects can limit the potential of host-specific insects to induce negative-density dependence in plant populations.

Published
2011

37. Tri-trophic interactions affect density dependence of seed fate in a tropical forest palm.

Author

Visser MD, Muller-Landau HC, Wright SJ, Rutten G, and Jansen PA

Subjects
Animals, Coleoptera physiology, Ecosystem, Food Chain, Invertebrates, Larva, Population Density, Rodentia, Tropical Climate, Arecaceae, Seeds, Trees
Abstract

Natural enemies, especially host-specific enemies, are hypothesised to facilitate the coexistence of plant species by disproportionately inflicting more damage at increasing host abundance. However, few studies have assessed such Janzen-Connell mechanisms on a scale relevant for coexistence and no study has evaluated potential top-down influences on the specialized pests. We quantified seed predation by specialist invertebrates and generalist vertebrates, as well as larval predation on these invertebrates, for the Neotropical palm Attalea butyracea across ten 4-ha plots spanning 20-fold variation in palm density. As palm density increased, seed attack by bruchid beetles increased, whereas seed predation by rodents held constant. But because rodent predation on bruchid larvae increased disproportionately with increasing palm density, bruchid emergence rates and total seed predation by rodents and bruchids combined were both density-independent. Our results demonstrate that top-down effects can limit the potential of host-specific insects to induce negative-density dependence in plant populations., (© 2011 Blackwell Publishing Ltd/CNRS.)

Published
2011
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results