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Girard-Tercieux C, Maréchaux I, Clark AT, Clark JS, Courbaud B, Fortunel C, Guillemot J, Künstler G, le Maire G, Pélissier R, Rüger N, Vieilledent G. Rethinking the nature of intraspecific variability and its consequences on species coexistence. Ecol Evol 2023; 13:e9860. [PMID: 36911314 PMCID: PMC9992775 DOI: 10.1002/ece3.9860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 01/20/2023] [Accepted: 02/09/2023] [Indexed: 03/14/2023] Open
Abstract
Intraspecific variability (IV) has been proposed to explain species coexistence in diverse communities. Assuming, sometimes implicitly, that conspecific individuals can perform differently in the same environment and that IV increases niche overlap, previous studies have found contrasting results regarding the effect of IV on species coexistence. We aim at showing that the large IV observed in data does not mean that conspecific individuals are necessarily different in their response to the environment and that the role of high-dimensional environmental variation in determining IV has largely remained unexplored in forest plant communities. We first used a simulation experiment where an individual attribute is derived from a high-dimensional model, representing "perfect knowledge" of individual response to the environment, to illustrate how large observed IV can result from "imperfect knowledge" of the environment. Second, using growth data from clonal Eucalyptus plantations in Brazil, we estimated a major contribution of the environment in determining individual growth. Third, using tree growth data from long-term tropical forest inventories in French Guiana, Panama and India, we showed that tree growth in tropical forests is structured spatially and that despite a large observed IV at the population level, conspecific individuals perform more similarly locally than compared with heterospecific individuals. As the number of environmental dimensions that are well quantified at fine scale is generally lower than the actual number of dimensions influencing individual attributes, a great part of observed IV might be represented as random variation across individuals when in fact it is environmentally driven. This mis-representation has important consequences for inference about community dynamics. We emphasize that observed IV does not necessarily impact species coexistence per se but can reveal species response to high-dimensional environment, which is consistent with niche theory and the observation of the many differences between species in nature.
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Affiliation(s)
| | | | - Adam T Clark
- Institute of Biology Karl-Franzens University of Graz Graz Austria
| | - James S Clark
- Nicholas School of the Environment Duke University Durham North Carolina USA.,Univ. Grenoble Alpes, INRAE, LESSEM St-Martin-d'Hères France
| | - Benoît Courbaud
- Univ. Grenoble Alpes, INRAE, LESSEM St-Martin-d'Hères France
| | - Claire Fortunel
- AMAP, Univ. Montpellier, CIRAD, CNRS, INRAE, IRD Montpellier France
| | - Joannès Guillemot
- Eco&Sols, Univ. Montpellier, CIRAD, INRAE, IRD, Institut Agro Montpellier France
| | | | - Guerric le Maire
- Eco&Sols, Univ. Montpellier, CIRAD, INRAE, IRD, Institut Agro Montpellier France
| | - Raphaël Pélissier
- AMAP, Univ. Montpellier, CIRAD, CNRS, INRAE, IRD Montpellier France.,Department of Ecology French Institute of Pondicherry Puducherry India
| | - Nadja Rüger
- Department of Economics University of Leipzig Leipzig Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig Leipzig Germany.,Smithsonian Tropical Research Institute Balboa Panama
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Spatial distribution pattern of dominant tree species in different disturbance plots in the Changbai Mountain. Sci Rep 2022; 12:14161. [PMID: 35986205 PMCID: PMC9391346 DOI: 10.1038/s41598-022-18621-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 08/16/2022] [Indexed: 11/30/2022] Open
Abstract
The effects of disturbance on spatial patterns and species interactions provide critical information on community structure and species coexistence. Two standard plots of 1-ha were set, one of them was a sample plot with retrograde succession after disturbance, and the other one was undisturbed. Spatial indices and Spatial patterns statistics were used to analyze the spatial pattern and inter-specific correlation of main tree species in two plots. Our results showed that the diameter distributions of different species have reverse J-shape, unimodal and bimodal distribution in the disturbed plot, while bell-shaped curves were observed in the undisturbed plot. The distributions of tree species were mainly showed clustered patterns in almost all scales through univariate pair correlation function. Some similar results of the classification of Wiegand scheme of species association consistent with the consequences of the bivariate pair correlation. The mark variograms showed positive autocorrelation at a coarse scale. The current study may aid in efforts of forest management planning and ecosystem services. Meanwhile, different research methods of spatial distribution also help to improve the accuracy of spatial distribution and the interspecific association of tree species.
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Li YY, Boeraeve M, Cho YH, Jacquemyn H, Lee YI. Mycorrhizal Switching and the Role of Fungal Abundance in Seed Germination in a Fully Mycoheterotrophic Orchid, Gastrodia confusoides. FRONTIERS IN PLANT SCIENCE 2022; 12:775290. [PMID: 35095954 PMCID: PMC8792533 DOI: 10.3389/fpls.2021.775290] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Mycorrhizal associations are essential for orchid germination and seedling establishment, and thus may constrain the distribution and abundance of orchids under natural conditions. Previous studies have shown that germination and seedling establishment in several orchids often decline with increasing distance from adult plants, resulting in non-random spatial patterns of seedling establishment. In contrast, individuals of the fully mycoheterotrophic orchid Gastrodia confusoides often tend to have random aboveground spatial patterns of distribution within bamboo forests. Since G. confusoides is parasitic on litter-decaying fungi, its random spatial patterns of distribution may be due to highly scattered patterns of litter-decaying fungi within bamboo forests. To test this hypothesis, we first identified the main mycorrhizal fungi associating with developing seeds and adult plants at a bamboo forest site in Taiwan using Miseq high-throughput DNA sequencing. Next, we combined seed germination experiments with quantitative PCR (qPCR) analyses to investigate to what extent the abundance of mycorrhizal fungi affected spatial patterns of seed germination. Our results show that seed germination and subsequent growth to an adult stage in G. confusoides required a distinct switch in mycorrhizal partners, in which protocorms associated with a single Mycena OTU, while adults mainly associated with an OTU from the genus Gymnopus. A strong, positive relationship was observed between germination and Mycena abundance in the litter, but not between germination and Gymnopus abundance. Fungal abundance was not significantly related to the distance from the adult plants, and consequently germination was also not significantly related to the distance from adult plants. Our results provide the first evidence that the abundance of litter-decaying fungi varies randomly within the bamboo forest and independently from G. confusoides adults.
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Affiliation(s)
- Yuan-Yuan Li
- Beijing Key Laboratory of Seed Disease Testing and Control, College of Plant Protection, China Agricultural University, Beijing, China
| | - Margaux Boeraeve
- Department of Biology, Plant Conservation and Population Biology, KU Leuven, Leuven, Belgium
| | - Yu-Hsiu Cho
- Biology Department, National Museum of Natural Science, Taichung, Taiwan
| | - Hans Jacquemyn
- Department of Biology, Plant Conservation and Population Biology, KU Leuven, Leuven, Belgium
| | - Yung-I Lee
- Department of Life Science, National Taiwan University, Taipei, Taiwan
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4
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Mridha MF, Das SC, Kabir MM, Lima AA, Islam MR, Watanobe Y. Brain-Computer Interface: Advancement and Challenges. SENSORS 2021; 21:s21175746. [PMID: 34502636 PMCID: PMC8433803 DOI: 10.3390/s21175746] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 08/15/2021] [Accepted: 08/20/2021] [Indexed: 02/04/2023]
Abstract
Brain-Computer Interface (BCI) is an advanced and multidisciplinary active research domain based on neuroscience, signal processing, biomedical sensors, hardware, etc. Since the last decades, several groundbreaking research has been conducted in this domain. Still, no comprehensive review that covers the BCI domain completely has been conducted yet. Hence, a comprehensive overview of the BCI domain is presented in this study. This study covers several applications of BCI and upholds the significance of this domain. Then, each element of BCI systems, including techniques, datasets, feature extraction methods, evaluation measurement matrices, existing BCI algorithms, and classifiers, are explained concisely. In addition, a brief overview of the technologies or hardware, mostly sensors used in BCI, is appended. Finally, the paper investigates several unsolved challenges of the BCI and explains them with possible solutions.
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Affiliation(s)
- M. F. Mridha
- Department of Computer Science and Engineering, Bangladesh University of Business and Technology, Dhaka 1216, Bangladesh; (M.F.M.); (S.C.D.); (M.M.K.); (A.A.L.)
| | - Sujoy Chandra Das
- Department of Computer Science and Engineering, Bangladesh University of Business and Technology, Dhaka 1216, Bangladesh; (M.F.M.); (S.C.D.); (M.M.K.); (A.A.L.)
| | - Muhammad Mohsin Kabir
- Department of Computer Science and Engineering, Bangladesh University of Business and Technology, Dhaka 1216, Bangladesh; (M.F.M.); (S.C.D.); (M.M.K.); (A.A.L.)
| | - Aklima Akter Lima
- Department of Computer Science and Engineering, Bangladesh University of Business and Technology, Dhaka 1216, Bangladesh; (M.F.M.); (S.C.D.); (M.M.K.); (A.A.L.)
| | - Md. Rashedul Islam
- Department of Computer Science and Engineering, University of Asia Pacific, Dhaka 1216, Bangladesh
- Correspondence:
| | - Yutaka Watanobe
- Department of Computer Science and Engineering, University of Aizu, Aizu-Wakamatsu 965-8580, Japan;
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5
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Wiegand T, Wang X, Anderson-Teixeira KJ, Bourg NA, Cao M, Ci X, Davies SJ, Hao Z, Howe RW, Kress WJ, Lian J, Li J, Lin L, Lin Y, Ma K, McShea W, Mi X, Su SH, Sun IF, Wolf A, Ye W, Huth A. Consequences of spatial patterns for coexistence in species-rich plant communities. Nat Ecol Evol 2021; 5:965-973. [PMID: 33941904 PMCID: PMC8257505 DOI: 10.1038/s41559-021-01440-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 03/01/2021] [Indexed: 02/02/2023]
Abstract
Ecology cannot yet fully explain why so many tree species coexist in natural communities such as tropical forests. A major difficulty is linking individual-level processes to community dynamics. We propose a combination of tree spatial data, spatial statistics and dynamical theory to reveal the relationship between spatial patterns and population-level interaction coefficients and their consequences for multispecies dynamics and coexistence. Here we show that the emerging population-level interaction coefficients have, for a broad range of circumstances, a simpler structure than their individual-level counterparts, which allows for an analytical treatment of equilibrium and stability conditions. Mechanisms such as animal seed dispersal, which result in clustering of recruits that is decoupled from parent locations, lead to a rare-species advantage and coexistence of otherwise neutral competitors. Linking spatial statistics with theories of community dynamics offers new avenues for explaining species coexistence and calls for rethinking community ecology through a spatial lens.
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Affiliation(s)
- Thorsten Wiegand
- Department of Ecological Modelling, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany.
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.
| | - Xugao Wang
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, .
| | - Kristina J Anderson-Teixeira
- Conservation Ecology Center, Smithsonian Conservation Biology Institute, Front Royal, VA, USA
- Forest Global Earth Observatory (ForestGEO), Smithsonian Tropical Research Institute, Washington, DC, USA
| | - Norman A Bourg
- Conservation Ecology Center, Smithsonian Conservation Biology Institute, Front Royal, VA, USA
| | - Min Cao
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences
| | - Xiuqin Ci
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences
- Centre for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences
| | - Stuart J Davies
- Forest Global Earth Observatory (ForestGEO), Smithsonian Tropical Research Institute, Washington, DC, USA
| | - Zhanqing Hao
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences
- School of Ecology and Environment, Northwestern Polytechnical University
| | - Robert W Howe
- Department of Natural and Applied Sciences, University of Wisconsin-Green Bay, Green Bay, WI, USA
| | - W John Kress
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Juyu Lian
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences
| | - Jie Li
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences
- Centre for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences
| | - Luxiang Lin
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences
| | - Yiching Lin
- Department of Life Science, Tunghai University
| | - Keping Ma
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences
| | - William McShea
- Conservation Ecology Center, Smithsonian Conservation Biology Institute, Front Royal, VA, USA
| | - Xiangcheng Mi
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences
| | | | - I-Fang Sun
- Center for Interdisciplinary Research on Ecology and Sustainability, National Dong Hwa University
| | - Amy Wolf
- Department of Natural and Applied Sciences, University of Wisconsin-Green Bay, Green Bay, WI, USA
| | - Wanhui Ye
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences
| | - Andreas Huth
- Department of Ecological Modelling, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
- Institute of Environmental Systems Research, University of Osnabrück, Osnabrück, Germany
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6
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Keil P, Wiegand T, Tóth AB, McGlinn DJ, Chase JM. Measurement and analysis of interspecific spatial associations as a facet of biodiversity. ECOL MONOGR 2021. [DOI: 10.1002/ecm.1452] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Petr Keil
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐Leipzig Deutscher Platz 5e 04103 Leipzig Germany
- Institute of Computer Science Martin Luther University Halle‐Wittenberg 06120 Halle (Saale) Germany
- Faculty of Environmental Sciences Czech University of Life Sciences Prague Kamýcká 129 Praha – Suchdol165 00 Czech Republic
| | - Thorsten Wiegand
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐Leipzig Deutscher Platz 5e 04103 Leipzig Germany
- Department of Ecological Modelling Helmholtz Centre for Environmental Research ‐ UFZ 04318 Leipzig Germany
| | - Anikó B. Tóth
- Centre for Ecosystem Sciences School of Biological, Earth and Environmental Sciences University of New South Wales Sydney NSW 2052 Australia
| | - Daniel J. McGlinn
- Department of Biology College of Charleston Charleston South Carolina 29401 USA
| | - Jonathan M. Chase
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐Leipzig Deutscher Platz 5e 04103 Leipzig Germany
- Institute of Computer Science Martin Luther University Halle‐Wittenberg 06120 Halle (Saale) Germany
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Ribeiro KFO, Martins VF, Wiegand T, Santos FAM. Habitat filtering drives the local distribution of congeneric species in a Brazilian white-sand flooded tropical forest. Ecol Evol 2021; 11:1797-1813. [PMID: 33614004 PMCID: PMC7882942 DOI: 10.1002/ece3.7169] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 12/08/2020] [Accepted: 12/10/2020] [Indexed: 01/29/2023] Open
Abstract
The investigation of ecological processes that maintain species coexistence is revealing in naturally disturbed environments such as the white-sand tropical forest, which is subject to periodic flooding that might pose strong habitat filtering to tree species. Congeneric species are a good model to investigate the relative importance of ecological processes that maintain high species diversity because they tend to exploit the same limiting resources and/or have similar tolerance limits to the same environmental conditions due to their close phylogenetic relationship. We aim to find evidence for the action and relative importance of different processes hypothesized to maintain species coexistence in a white-sand flooded forest in Brazil, taking advantage of data on the detailed spatial structure of populations of congeneric species. Individuals of three Myrcia species were tagged, mapped, and measured for diameter at soil height in a 1-ha plot. We also sampled seven environmental variables in the plot. We employed several spatial point process models to investigate the possible action of habitat filtering, interspecific competition, and dispersal limitation. Habitat filtering was the most important process driving the local distribution of the three Myrcia species, as they showed associations, albeit of different strength, to environmental variables related to flooding. We did not detect spatial patterns, such as spatial segregation and smaller size of nearby neighbors, that would be consistent with interspecific competition among the three congeneric species and other co-occurring species. Even though congeners were spatially independent, they responded to differences in the environment. Last, dispersal limitation only led to spatial associations of different size classes for one of the species. Given that white-sand flooded forests are highly threatened in Brazil, the preservation of their different habitats is of utmost importance to the maintenance of high species richness, as flooding drives the distribution of species in the community.
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Affiliation(s)
- Kelly F. O. Ribeiro
- Programa de Pós‐Graduação em EcologiaInstitute of BiologyUniversity of Campinas ‐ UNICAMPCampinasBrazil
| | - Valéria F. Martins
- Department of Natural Sciences, Maths and EducationFederal University of São Carlos ‐ UFSCarArarasBrazil
- Department of Plant BiologyInstitute of BiologyUniversity of Campinas ‐ UNICAMPCampinasBrazil
| | - Thorsten Wiegand
- Department of Ecological ModellingHelmholtz Centre for Environmental Research – UFZLeipzigGermany
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐LeipzigLeipzigGermany
| | - Flavio A. M. Santos
- Department of Plant BiologyInstitute of BiologyUniversity of Campinas ‐ UNICAMPCampinasBrazil
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Phylogenetic Community and Nearest Neighbor Structure of Disturbed Tropical Rain Forests Encroached by Streblus macrophyllus. FORESTS 2020. [DOI: 10.3390/f11070722] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Although woody plant encroachment of tropical forest ecosystems has been related to altered disturbance regimes, its impacts on the nearest neighborhood structures and community phylogenetics are still poorly understood. Streblus macrophyllus is a light-demanding species during its early life stages and is shade-tolerant as a mature tree. S. macrophyllus can be found in tropical karst evergreen forests in northern Vietnam. It often regenerates at high densities in anthropogenic disturbed forest stands. To understand the structural patterns of disturbed forests encroached by S. macrophyllus at different abundance levels, three fully mapped 1-ha plots were established in Cuc Phuong National Park. Methods considering the phylogenetic community and nearest neighbor statistics were applied to identify how community structure changes during S. macrophyllus encroachment. Results showed that phylogenetic distance, phylogenetic diversity, and mean phylogenetic distance increased when species diversity increased and the abundance of S. macrophyllus decreased in forest communities. Net related index values were positive, which indicates a clustered phylogenetic structure among all sampled forest communities. S. macrophyllus trees were mixed well with heterospecifics and had regular to aggregated distributions, whereas the species showed evidence of being a strong competitor with its neighbors. Competition could be a major ecological process regulating forest communities encroached by S. macrophyllus. According to the forest disturbance effects, phylogenetic community properties showed the loss of phylogenetic relatedness when S. macrophyllus increased in abundance. To our knowledge, S. macrophyllus encroaches tropical rain forest communities as a disturbance-adapted species.
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10
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Żywiec M, Fedriani JM, Kurek P, Holeksa J. Non‐trophic plant–animal interactions mediate positive density dependence among conspecific saplings. OIKOS 2019. [DOI: 10.1111/oik.06071] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Magdalena Żywiec
- Centre for Applied Ecology ‘Prof. Baeta Neves’ (CEABN‐InBIO), Inst. Superior of Agronomy, Univ. of Lisbon Lisboa Portugal
- W. Szafer Inst. of Botany, Polish Academy of Sciences Lubicz 46, 31 512 Kraków Poland
| | - José M. Fedriani
- Centre for Applied Ecology ‘Prof. Baeta Neves’ (CEABN‐InBIO), Inst. Superior of Agronomy, Univ. of Lisbon Lisboa Portugal
- Dept of Conservation Biology, Estacion Biologica de Doñana (EBD – CSIC) Seville Spain
| | - Przemysław Kurek
- Dept of Plant Ecology and Environmental Protection, Faculty of Biology, Adam Mickiewicz Univ Poznań Poland
| | - Jan Holeksa
- Dept of Plant Ecology and Environmental Protection, Faculty of Biology, Adam Mickiewicz Univ Poznań Poland
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11
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Hülsmann L, Hartig F. Comment on “Plant diversity increases with the strength of negative density dependence at the global scale”. Science 2018; 360:360/6391/eaar2435. [DOI: 10.1126/science.aar2435] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 04/18/2018] [Indexed: 01/27/2023]
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12
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Nearest Neighborhood Characteristics of a Tropical Mixed Broadleaved Forest Stand. FORESTS 2018. [DOI: 10.3390/f9010033] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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13
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Zwolak R. How intraspecific variation in seed-dispersing animals matters for plants. Biol Rev Camb Philos Soc 2017; 93:897-913. [DOI: 10.1111/brv.12377] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 09/13/2017] [Accepted: 09/18/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Rafał Zwolak
- Department of Systematic Zoology, Faculty of Biology; Adam Mickiewicz University, Umultowska 89; 61-614 Poznań Poland
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14
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Murphy SJ, Wiegand T, Comita LS. Distance-dependent seedling mortality and long-term spacing dynamics in a neotropical forest community. Ecol Lett 2017; 20:1469-1478. [PMID: 28980377 DOI: 10.1111/ele.12856] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 08/17/2017] [Accepted: 09/01/2017] [Indexed: 01/25/2023]
Abstract
Negative distance dependence (NDisD), or reduced recruitment near adult conspecifics, is thought to explain the astounding diversity of tropical forests. While many studies show greater mortality at near vs. far distances from adults, these studies do not seek to track changes in the peak seedling curve over time, thus limiting our ability to link NDisD to coexistence. Using census data collected over 12 years from central Panama in conjunction with spatial mark-connection functions, we show evidence for NDisD for many species, and find that the peak seedling curve shifts away from conspecific adults over time. We find wide variation in the strength of NDisD, which was correlated with seed size and canopy position, but other life-history traits showed no relationship with variation in NDisD mortality. Our results document shifts in peak seedling densities over time, thus providing evidence for the hypothesized spacing mechanism necessary for diversity maintenance in tropical forests.
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Affiliation(s)
- Stephen J Murphy
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, 318 W. 12th Avenue, Columbus, OH, 43210-1293, USA.,School of Forestry and Environmental Studies, Yale University, 195 Prospect Street, New Haven, CT, 06511, USA
| | - Thorsten Wiegand
- Department of Ecological Modelling, Helmholtz Centre for Environmental Research-UFZ, Permoserstrasse 15, Leipzig, 04318, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany
| | - Liza S Comita
- School of Forestry and Environmental Studies, Yale University, 195 Prospect Street, New Haven, CT, 06511, USA.,Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancón, Panama
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15
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Choo J, Carasco C, Alvarez-Loayza P, Simpson BB, Economo EP. Life history traits influence the strength of distance- and density-dependence at different life stages of two Amazonian palms. ANNALS OF BOTANY 2017; 120:147-158. [PMID: 28549080 PMCID: PMC5737847 DOI: 10.1093/aob/mcx051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 04/05/2017] [Indexed: 06/01/2023]
Abstract
Background and Aims Natural enemies are known to be important in regulating plant populations and contributing to species coexistence (Janzen-Connell effects). The strength of Janzen-Connell effects (both distance- and density-effects) varies across species, but the life history traits that may mediate such a variation are not well understood. This study examined Janzen-Connell effects across the life stages (seed through adult stages) of two sympatric palm species with distinct phenologies and shade tolerances, two traits that may mediate the strength and timing of Janzen-Connell effects. Methods Populations of two common palm species, Attalea phalerata and Astrocaryum murumuru , were studied in Manu National Park, Peru. Seed predation experiments were conducted to assess Janzen-Connell effects at the seed stage. In the post-seed stages, spatial point pattern analyses of the distributions of individuals and biomass were used to infer the strength of distance- and density-effects. Key Results Seed predation was both negative distance- and density-dependent consistent with the Janzen-Connell effects. However, only seedling recruitment for asynchronously fruiting Attalea phalerata was depressed near adults while recruitment remained high for synchronously fruiting Astrocaryum murumuru , consistent with weak distance-effects. Negative density-effects were strong in the early stages for shade-intolerant Attalea phalerata but weak or absent in shade-tolerant Astrocaryum murumuru. Conclusions Distance- and density-effects varied among the life stages of the two palm species in a manner that corresponded to their contrasting phenology and shade tolerance. Generalizing such connections across many species would provide a route to understanding how trait-mediated Janzen-Connell effects scale up to whole communities of species.
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Affiliation(s)
- Juanita Choo
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa, Japan 904-0495
| | - Cecilia Carasco
- Universidad Nacional San Antonio Abad del Cusco, Jr. Victoria Palestina FF-2 Santiago, Departamento de Cusco, Peru
| | | | - Beryl B. Simpson
- Department of Integrative Biology, The University of Texas at Austin, 1 University Station CO930, Austin, TX 78712, USA
| | - Evan P. Economo
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa, Japan 904-0495
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Jácome-Flores ME, Delibes M, Wiegand T, Fedriani JM. Spatial patterns of an endemic Mediterranean palm recolonizing old fields. Ecol Evol 2016; 6:8556-8568. [PMID: 28031807 PMCID: PMC5167057 DOI: 10.1002/ece3.2504] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 08/20/2016] [Accepted: 08/30/2016] [Indexed: 11/10/2022] Open
Abstract
Throughout Europe, increased levels of land abandonment lead to (re)colonization of old lands by forests and shrublands. Very little is known about the spatial pattern of plants recolonizing such old fields. We mapped in two 21-22-ha plots, located in the Doñana National Park (Spain), all adult individuals of the endozoochorous dwarf palm Chamaerops humilisL. and determined their sex and sizes. We used techniques of spatial point pattern analysis (SPPA) to precisely quantify the spatial structure of these C. humilis populations. The objective was to identify potential processes generating the patterns and their likely consequences on palm reproductive success. We used (1) Thomas point process models to describe the clustering of the populations, (2) random labeling to test the sexual spatial segregation, and (3) mark correlation functions to assess spatial structure in plant sizes. Plants in both plots showed two critical scales of clustering, with small clusters of a radius of 2.8-4 m nested within large clusters with 38-44 m radius. Additional to the clustered individuals, 11% and 27% of all C. humilis individuals belonged to a random pattern that was independently superimposed to the clustered pattern. The complex spatial pattern of C. humilis could be explained by the effect of different seed-dispersers and predators' behavior and their relative abundances. Plant sexes had no spatial segregation. Plant sizes showed a spatial aggregation inside the clusters, with a decreasing correlation with distance. Clustering of C. humilis is strongly reliant on its seed dispersers and stressful environmental conditions. However, it seems that the spatial patterns and dispersal strategies of the dwarf palm make it a successful plant for new habitat colonization. Our results provide new information on the colonization ability of C. humilis and can help to develop management strategies to recover plant populations.
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Affiliation(s)
- Miguel E Jácome-Flores
- Department of Conservation Biology Estación Biológica de Doñana (EBD-CSIC) Seville Spain
| | - Miguel Delibes
- Department of Conservation Biology Estación Biológica de Doñana (EBD-CSIC) Seville Spain
| | - Thorsten Wiegand
- Department of Ecological Modelling Helmholtz Centre for Environmental Research GmbH - UFZ Leipzig Germany; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig Leipzig Germany
| | - José M Fedriani
- Department of Conservation Biology Estación Biológica de Doñana (EBD-CSIC) Seville Spain; Department of Ecological Modelling Helmholtz Centre for Environmental Research GmbH - UFZ Leipzig Germany; Technical University of Lisbon Institute of Agronomy Centre for Applied Ecology Lisboa Portugal
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17
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Waud M, Wiegand T, Brys R, Lievens B, Jacquemyn H. Nonrandom seedling establishment corresponds with distance-dependent decline in mycorrhizal abundance in two terrestrial orchids. THE NEW PHYTOLOGIST 2016; 211:255-64. [PMID: 26876007 DOI: 10.1111/nph.13894] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 01/13/2016] [Indexed: 05/04/2023]
Abstract
In plant species that critically rely on mycorrhizal symbionts for germination and seedling establishment, distance-dependent decline of mycorrhizal fungi in the soil can be hypothesized to lead to significant spatial clustering as a result of nonrandom spatial patterns of seedling establishment. To test this hypothesis, we investigated the abundance and distribution of mycorrhizal fungi in the soil and how they relate to spatial patterns of adults and seedling recruitment in two related orchid species. We combined assessments of spatial variation in fungal abundance using quantitative PCR (qPCR) with spatial point pattern analyses based on long-term demographic data and cluster point process models. qPCR analyses showed that fungal abundance declined rapidly with distance from the adult host plants. Spatial point pattern analyses showed that successful recruitment in both species was clustered significantly around adult plants and that the decline in the neighborhood density of recruits around adults coincided with the decline of fungal abundance around adult plants. Overall, these results indicate that the distribution and abundance of fungal associates in the soil may have a strong impact on the aboveground distribution of its partner.
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Affiliation(s)
- Michael Waud
- Department of Biology, Plant Conservation and Population Biology, KU Leuven, B-3001, Leuven, Belgium
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M2S), KU Leuven, Campus De Nayer, B-2860, Sint-Katelijne-Waver, Belgium
| | - Thorsten Wiegand
- Department of Ecological Modelling, UFZ Helmholtz Centre for Environmental Research, Permoserstrasse 15, 04318, Leipzig, Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany
| | - Rein Brys
- Research Institute for Forest and Nature, Kliniekstraat 25, B-1070, Brussels, Belgium
| | - Bart Lievens
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M2S), KU Leuven, Campus De Nayer, B-2860, Sint-Katelijne-Waver, Belgium
| | - Hans Jacquemyn
- Department of Biology, Plant Conservation and Population Biology, KU Leuven, B-3001, Leuven, Belgium
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Wang X, Wiegand T, Kraft NJB, Swenson NG, Davies SJ, Hao Z, Howe R, Lin Y, Ma K, Mi X, Su SH, Sun IF, Wolf A. Stochastic dilution effects weaken deterministic effects of niche-based processes in species rich forests. Ecology 2016; 97:347-60. [PMID: 27145610 DOI: 10.1890/14-2357.1] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Recent theory predicts that stochastic dilution effects may result in species-rich communities with statistically independent species spatial distributions, even if the underlying ecological processes structuring the community are driven by deterministic niche differences. Stochastic dilution is a consequence of the stochastic geometry of biodiversity where the identities of the nearest neighbors of individuals of a given species are largely unpredictable. Under such circumstances, the outcome of deterministic species interactions may vary greatly among individuals of a given species. Consequently, nonrandom patterns in the biotic neighborhoods of species, which might be expected from coexistence or community assembly theory (e.g., individuals of a given species are neighbored by phylogenetically similar species), are weakened or do not emerge, resulting in statistical independence of species spatial distributions. We used data on phylogenetic and functional similarity of tree species in five large forest dynamics plots located across a gradient of species richness to test predictions of the stochastic dilution hypothesis. To quantify the biotic neighborhood of a focal species we used the mean phylogenetic (or functional) dissimilarity of the individuals of the focal species to all species within a local neighborhood. We then compared the biotic neighborhood of species to predictions from stochastic null models to test if a focal species was surrounded by more or less similar species than expected by chance. The proportions of focal species that showed spatial independence with respect to their biotic neighborhoods increased with total species richness. Locally dominant, high-abundance species were more likely to be surrounded by species that were statistically more similar or more dissimilar than expected by chance. Our results suggest that stochasticity may play a stronger role in shaping the spatial structure of species rich tropical forest communities than it does in species poorer forests. These findings represent an important step towards understanding the factors that govern the spatial configuration of local biotic communities. The stochastic dilution effect is a simple geometric mechanism that can explain why species' spatial distributions in species-rich communities approximate independence from their biotic neighborhood, even if deterministic niche processes are in effect.
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Spatial patterns of primary seed dispersal and adult tree distributions: Genipa americana dispersed by Cebus capucinus. JOURNAL OF TROPICAL ECOLOGY 2015. [DOI: 10.1017/s0266467415000413] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Abstract:The spatial distribution of adult trees is typically not expected to reflect the spatial patterns of primary seed dispersal, due to many factors influencing post-dispersal modification of the seed shadow, such as seed predation, secondary seed dispersal and density-dependent survival. Here, we test the hypothesis that spatial distributions of primary seed shadows and adult trees are concordant by analysing the spatial distributions of adult Genipa americana trees and the seed shadow produced by its key primary disperser, the capuchin monkey (Cebus capucinus) in a tropical dry forest in Costa Rica. We mapped the dispersal of G. americana seeds by the capuchins during focal animal follows (mean = 463 min, n = 50) of all adults in one free-ranging group over two early wet seasons (May–July, 2005 and 2006). We mapped the locations of all G. americana trees within a 60-ha plot that lay within the home range of the capuchin group. We conducted multiple spatial point pattern analyses comparing degrees of clustering of capuchin defecations and G. americana trees. We found that adult tree distributions and primary dispersal patterns are similarly aggregated at multiple spatial scales, despite the modification of the primary dispersal patterns and long dispersal distances.
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Abstract
Spatial ecological patterns reflect the underlying processes that shape the structure of species and communities. Mechanisms like intra- and inter-specific competition, dispersal and host-pathogen interactions can act over a wide range of scales. Yet, the inference of such processes from patterns is a challenging task. Here we call attention to a quite unexpected phenomenon in the extensively studied tropical forest at the Barro-Colorado Island (BCI): the spatial deployment of (almost) all tree species is statistically equivalent, once distances are normalized by ℓ0, the typical distance between neighboring conspecific trees. Correlation function, cluster statistics and nearest-neighbor distance distribution become species-independent after this rescaling. Global observables (species frequencies) and local spatial structure appear to be interrelated. This "glocality" suggests a radical interpretation of recent experiments that show a correlation between species' abundance and the negative feedback among conspecifics. For the forest to be glocal, the negative feedback must govern spatial patterns over all scales.
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