1
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Grele A, Massad TJ, Uckele KA, Dyer LA, Antonini Y, Braga L, Forister ML, Sulca L, Kato M, Lopez HG, Nascimento AR, Parchman T, Simbaña WR, Smilanich AM, Stireman JO, Tepe EJ, Walla T, Richards LA. Intra- and interspecific diversity in a tropical plant clade alter herbivory and ecosystem resilience. eLife 2024; 12:RP86988. [PMID: 38662411 PMCID: PMC11045218 DOI: 10.7554/elife.86988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024] Open
Abstract
Declines in biodiversity generated by anthropogenic stressors at both species and population levels can alter emergent processes instrumental to ecosystem function and resilience. As such, understanding the role of biodiversity in ecosystem function and its response to climate perturbation is increasingly important, especially in tropical systems where responses to changes in biodiversity are less predictable and more challenging to assess experimentally. Using large-scale transplant experiments conducted at five neotropical sites, we documented the impacts of changes in intraspecific and interspecific plant richness in the genus Piper on insect herbivory, insect richness, and ecosystem resilience to perturbations in water availability. We found that reductions of both intraspecific and interspecific Piper diversity had measurable and site-specific effects on herbivory, herbivorous insect richness, and plant mortality. The responses of these ecosystem-relevant processes to reduced intraspecific Piper richness were often similar in magnitude to the effects of reduced interspecific richness. Increased water availability reduced herbivory by 4.2% overall, and the response of herbivorous insect richness and herbivory to water availability were altered by both intra- and interspecific richness in a site-dependent manner. Our results underscore the role of intraspecific and interspecific richness as foundations of ecosystem function and the importance of community and location-specific contingencies in controlling function in complex tropical systems.
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Affiliation(s)
- Ari Grele
- Program in Ecology, Evolution, and Conservation Biology, Department of Biology, University of NevadaRenoUnited States
| | - Tara J Massad
- Department of Scientific Services, Gorongosa National ParkSofalaMozambique
| | - Kathryn A Uckele
- Program in Ecology, Evolution, and Conservation Biology, Department of Biology, University of NevadaRenoUnited States
| | - Lee A Dyer
- Program in Ecology, Evolution, and Conservation Biology, Department of Biology, University of NevadaRenoUnited States
- Hitchcock Center for Chemical Ecology, University of NevadaRenoUnited States
| | - Yasmine Antonini
- Lab. de Biodiversidade, Departamento de Biodiversidade, Evolução e Meio Ambiente, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro PretoOuro PretoBrazil
| | - Laura Braga
- Lab. de Biodiversidade, Departamento de Biodiversidade, Evolução e Meio Ambiente, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro PretoOuro PretoBrazil
| | - Matthew L Forister
- Program in Ecology, Evolution, and Conservation Biology, Department of Biology, University of NevadaRenoUnited States
- Hitchcock Center for Chemical Ecology, University of NevadaRenoUnited States
| | - Lidia Sulca
- Departamento de Entomología, Museo de Historia Natural, Universidad Nacional Mayor de San MarcosLimaPeru
| | - Massuo Kato
- Department of Fundamental Chemistry, Institute of Chemistry, University of São PauloSão PauloBrazil
| | - Humberto G Lopez
- Program in Ecology, Evolution, and Conservation Biology, Department of Biology, University of NevadaRenoUnited States
| | | | - Thomas Parchman
- Program in Ecology, Evolution, and Conservation Biology, Department of Biology, University of NevadaRenoUnited States
- Department of Biology, University of NevadaRenoUnited States
| | | | - Angela M Smilanich
- Program in Ecology, Evolution, and Conservation Biology, Department of Biology, University of NevadaRenoUnited States
| | - John O Stireman
- Department of Biological Sciences, Wright State UniversityDaytonUnited States
| | - Eric J Tepe
- Department of Biological Sciences, University of CincinnatiCincinnatiUnited States
| | - Thomas Walla
- Department of Biology, Mesa State CollegeGrand JunctionUnited States
| | - Lora A Richards
- Program in Ecology, Evolution, and Conservation Biology, Department of Biology, University of NevadaRenoUnited States
- Hitchcock Center for Chemical Ecology, University of NevadaRenoUnited States
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2
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Xu C, Silliman BR, Chen J, Li X, Thomsen MS, Zhang Q, Lee J, Lefcheck JS, Daleo P, Hughes BB, Jones HP, Wang R, Wang S, Smith CS, Xi X, Altieri AH, van de Koppel J, Palmer TM, Liu L, Wu J, Li B, He Q. Herbivory limits success of vegetation restoration globally. Science 2023; 382:589-594. [PMID: 37917679 DOI: 10.1126/science.add2814] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 09/21/2023] [Indexed: 11/04/2023]
Abstract
Restoring vegetation in degraded ecosystems is an increasingly common practice for promoting biodiversity and ecological function, but successful implementation is hampered by an incomplete understanding of the processes that limit restoration success. By synthesizing terrestrial and aquatic studies globally (2594 experimental tests from 610 articles), we reveal substantial herbivore control of vegetation under restoration. Herbivores at restoration sites reduced vegetation abundance more strongly (by 89%, on average) than those at relatively undegraded sites and suppressed, rather than fostered, plant diversity. These effects were particularly pronounced in regions with higher temperatures and lower precipitation. Excluding targeted herbivores temporarily or introducing their predators improved restoration by magnitudes similar to or greater than those achieved by managing plant competition or facilitation. Thus, managing herbivory is a promising strategy for enhancing vegetation restoration efforts.
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Affiliation(s)
- Changlin Xu
- MOE Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, School of Life Sciences, Fudan University, Shanghai, China
| | - Brian R Silliman
- Nicholas School of the Environment, Duke University, Beaufort, NC, USA
| | - Jianshe Chen
- MOE Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, School of Life Sciences, Fudan University, Shanghai, China
| | - Xincheng Li
- MOE Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, School of Life Sciences, Fudan University, Shanghai, China
| | - Mads S Thomsen
- Marine Ecology Research Group and Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- Department of Bioscience, Aarhus University, Roskilde, Denmark
| | - Qun Zhang
- MOE Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, School of Life Sciences, Fudan University, Shanghai, China
| | - Juhyung Lee
- Marine Science Center, Northeastern University, Nahant, MA, USA
- Department of Oceanography and Marine Research Institute, Pusan National University, Busan, Republic of Korea
| | - Jonathan S Lefcheck
- Tennenbaum Marine Observatories Network and MarineGEO Program, Smithsonian Environmental Research Center, Edgewater, MD, USA
- University of Maryland Center for Environmental Science, Cambridge, MD, USA
| | - Pedro Daleo
- Instituto de Investigaciones Marinas y Costeras (IIMyC), UNMdP, CONICETC, Mar del Plata, Argentina
| | - Brent B Hughes
- Department of Biology, Sonoma State University, Rohnert Park, CA, USA
| | - Holly P Jones
- Department of Biological Sciences and Institute for the Study of the Environment, Sustainability, and Energy, Northern Illinois University, DeKalb, IL, USA
| | - Rong Wang
- School of Ecological and Environmental Sciences, Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, East China Normal University, Shanghai, China
| | - Shaopeng Wang
- Institute of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, China
| | - Carter S Smith
- Nicholas School of the Environment, Duke University, Beaufort, NC, USA
| | - Xinqiang Xi
- Department of Ecology, School of Life Science, Nanjing University, Nanjing, Jiangsu, China
| | - Andrew H Altieri
- Department of Environmental Engineering Sciences, University of Florida, Gainesville, FL, USA
| | - Johan van de Koppel
- Department of Estuarine and Delta Systems, Royal Netherlands Institute for Sea Research, Yerseke, Netherlands
- Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands
| | - Todd M Palmer
- Department of Biology, University of Florida, Gainesville, FL, USA
| | - Lingli Liu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Jihua Wu
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, and College of Ecology, Lanzhou University, Lanzhou, Gansu, China
| | - Bo Li
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology and Centre for Invasion Biology, Institute of Biodiversity, School of Ecology and Environmental Science, Yunnan University, Kunming, Yunnan, China
| | - Qiang He
- MOE Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, School of Life Sciences, Fudan University, Shanghai, China
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3
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Mason DS, Baruzzi C, Lashley MA. Passive directed dispersal of plants by animals. Biol Rev Camb Philos Soc 2022; 97:1908-1929. [PMID: 35770842 DOI: 10.1111/brv.12875] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 11/27/2022]
Abstract
Conceptual gaps and imprecise terms and definitions may obscure the breadth of plant-animal dispersal relationships involved in directed dispersal. The term 'directed' indicates predictable delivery to favourable microsites. However, directed dispersal was initially considered uncommon in diffuse mutualisms (i.e. those involving many species), partly because plants rarely influence post-removal propagule fate without specialized adaptations. This rationale implies that donor plants play an active role in directed dispersal by manipulating vector behaviour after propagule removal. However, even in most classic examples of directed dispersal, participating plants do not influence animal behaviour after propagule removal. Instead, such plants may take advantage of vector attraction to favourable plant microsites, indicating a need to expand upon current interpretations of directed dispersal. We contend that directed dispersal can emerge whenever propagules are disproportionately delivered to favourable microsites as a result of predictably skewed vector behaviour. Thus, we propose distinguishing active and passive forms of directed dispersal. In active directed dispersal, the donor plant achieves disproportionate arrival to favourable microsites by influencing vector behaviour after propagule removal. By contrast, passive directed dispersal occurs when the donor plant takes advantage of vector behaviour to arrive at favourable microsites. Whereas predictable post-removal vector behaviour is dictated by characteristics of the donor plant in active directed dispersal, characteristics of the destination dictate predictable post-removal vector behaviour in passive directed dispersal. Importantly, this passive form of directed dispersal may emerge in more plant-animal dispersal relationships because specialized adaptations in donor plants that influence post-removal vector behaviour are not required. We explore the occurrence and consequences of passive directed dispersal using the unifying generalized gravity model of dispersal. This model successfully describes vectored dispersal by incorporating the influence of the environment (i.e. attractiveness of microsites) on vector movement. When applying gravity models to dispersal, the three components of Newton's gravity equation (i.e. gravitational force, object mass, and distance between centres of mass) become analogous to propagules moving towards a location based on characteristics of the donor plant, the destination, and relocation processes. The generalized gravity model predicts passive directed dispersal in plant-animal dispersal relationships when (i) animal vectors are predictably attracted to specific destinations, (ii) animal vectors disproportionately disperse propagules to those destinations, and (iii) those destinations are also favourable microsites for the dispersed plants. Our literature search produced evidence for these three conditions broadly, and we identified 13 distinct scenarios where passive directed dispersal likely occurs because vector behaviour is predictably skewed towards favourable microsites. We discuss the wide applicability of passive directed dispersal to plant-animal mutualisms and provide new insights into the vulnerability of those mutualisms to global change.
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Affiliation(s)
- David S Mason
- Wildlife Ecology and Conservation, University of Florida, PO Box 110430, 1745 McCarty Drive, Gainesville, FL, 32611-0410, USA
| | - Carolina Baruzzi
- School of Forest, Fisheries, and Geomatics Sciences, University of Florida, PO Box 110410, 1745 McCarty Drive, Gainesville, FL, 32611-0410, USA
| | - Marcus A Lashley
- Wildlife Ecology and Conservation, University of Florida, PO Box 110430, 1745 McCarty Drive, Gainesville, FL, 32611-0410, USA
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4
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Salazar D, Marquis RJ. Testing the role of local plant chemical diversity on plant-herbivore interactions and plant species coexistence. Ecology 2022; 103:e3765. [PMID: 35611398 DOI: 10.1002/ecy.3765] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 03/24/2022] [Accepted: 04/20/2022] [Indexed: 11/09/2022]
Abstract
Accumulating evidence suggests that herbivorous insects influence local composition and richness of Neotropical plant species, particularly in species-rich genera. Species richness, phylogenetic diversity, and chemical diversity all influence the ability of insect herbivores to find and utilize their hosts. The relative impact of these components of diversity on species coexistence and plant-herbivore interactions is not well understood. We constructed 60 local communities of up to 13 species of Piper (Piperaceae) in native, mature forest at a lowland wet forest location in Costa Rica. Species composition of each community was chosen such that species richness, phylogenetic diversity, and GCMS-based chemical diversity were varied independently among communities. We predicted that chemical diversity would most strongly affect the communities across time, with smaller effects of taxonomic and phylogenetic diversity. Thirteen months after the experimental planting, we assessed survivorship of each cutting, measured total leaf area loss of the survivors, leaf area loss to generalist and specialist herbivorous insect species, and local extinction of species. Generalist and specialist herbivory decreased with increasing levels of species richness and phylogenetic diversity, respectively. Surprisingly, there was no independent effect of chemical diversity on any of the three measures of herbivore damage. Nevertheless, plots with a higher chemical and phylogenetic diversity showed decreased plant mortality and local species extinction. Overall, our results suggest that both chemical and phylogenetic similarity are important factors in the assembly and maintenance of tropical plant communities. The fact that chemical diversity influences plant mortality suggests that leaf herbivores, and possibly other plant natural enemies, could increase plant diversity via selective mortality of similar chemotypes.
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Affiliation(s)
- Diego Salazar
- International Center for Tropical Botany, Institute of Environment, Department of Biological Sciences, Florida International University
| | - Robert J Marquis
- Department of Biology and the Whitney R. Harris World Ecology Center, University of Missouri-St. Louis, St. Louis, MO, United States
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5
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Massad TJ, Richards LA, Philbin C, Fumiko Yamaguchi L, Kato MJ, Jeffrey CS, Oliveira C, Ochsenrider K, M de Moraes M, Tepe EJ, Cebrian Torrejon G, Sandivo M, Dyer LA. The chemical ecology of tropical forest diversity: Environmental variation, chemical similarity, herbivory, and richness. Ecology 2022; 103:e3762. [PMID: 35593436 DOI: 10.1002/ecy.3762] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 03/01/2022] [Accepted: 03/18/2022] [Indexed: 11/11/2022]
Abstract
Species richness in tropical forests is correlated with other dimensions of diversity, including the diversity of plant-herbivore interactions and the phytochemical diversity that influences those interactions. Understanding the complexity of plant chemistry and the importance of phytochemical diversity for plant-insect interactions and overall forest richness has been enhanced significantly by the application of metabolomics to natural systems. The present work used proton nuclear magnetic resonance spectroscopy (1 H-NMR) profiling of crude leaf extracts to study phytochemical similarity and diversity among Piper plants growing naturally in the Atlantic Rainforest of Brazil. Spectral profile similarity and chemical diversity were quantified to examine the relationship between metrics of phytochemical diversity, specialist and generalist herbivory, and understory plant richness. Herbivory increased with understory species richness, while generalist herbivory increased and specialist herbivory decreased with the diversity of Piper leaf material available. Specialist herbivory increased when conspecific host plants were more spectroscopically dissimilar. Spectral similarity was lower among individuals of common species, and they were also more spectrally diverse, indicating phytochemical diversity is beneficial to plants. Canopy openness and soil nutrients also influenced chemistry and herbivory. The complex relationships uncovered in this study add information to our growing understanding of the importance of phytochemical diversity for plant-insect interactions and tropical plant species richness.
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Affiliation(s)
- Tara Joy Massad
- Department of Scientific Services, Gorongosa National Park, Sofala, Mozambique.,Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo, Brasil
| | - Lora A Richards
- Department of Biology, Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, NV, USA.,Hitchcock Center for Chemical Ecology, University of Nevada, Reno, NV, USA
| | - Casey Philbin
- Hitchcock Center for Chemical Ecology, University of Nevada, Reno, NV, USA.,Department of Chemistry, University of Nevada, Reno, NV, USA
| | | | - Massuo J Kato
- Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo, Brasil
| | - Christopher S Jeffrey
- Hitchcock Center for Chemical Ecology, University of Nevada, Reno, NV, USA.,Department of Chemistry, University of Nevada, Reno, NV, USA
| | - Celso Oliveira
- Department of Chemistry, University of Nevada, Reno, NV, USA
| | | | - Marcílio M de Moraes
- Departamento de Química, Universidade Federal Rural de Pernambuco, Pernambuco, Pernambuco, Brasil
| | - Eric J Tepe
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, USA
| | | | | | - Lee A Dyer
- Department of Biology, Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, NV, USA.,Hitchcock Center for Chemical Ecology, University of Nevada, Reno, NV, USA
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6
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Xi X, Yang Y, Tylianakis JM, Yang S, Dong Y, Sun S. Asymmetric interactions of seed-predation network contribute to rare-species advantage. Ecology 2020; 101:e03050. [PMID: 32233082 DOI: 10.1002/ecy.3050] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 02/25/2020] [Indexed: 01/11/2023]
Abstract
Although the asymmetry of species linkage within ecological networks is now well recognized, its effect on communities has scarcely been empirically investigated. Based on theory, we predicted that an asymmetric architecture of antagonistic plant-herbivore networks would emerge at the community level and that this asymmetry would negatively affect community-common plants more than rare ones. We tested this prediction by analyzing the architectural properties of an alpine plant and pre-dispersal seed-predator network and its effect on seed loss rate of plants in the Tibetan Plateau. This network showed an asymmetric architecture, where the common plant species (with a larger aboveground biomass per area) were infested by a higher number of predator species. Moreover, they asymmetrically interacted with specialized herbivores, presumably because of greater seed resource abundance. In turn, the asymmetric interactions led to a higher proportion of seed loss in the common plants at the species level. Our results suggest that asymmetric antagonistic networks may improve species coexistence by contributing to a mechanism of rare-species advantage.
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Affiliation(s)
- Xinqiang Xi
- Department of Ecology, School of Life Science, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
| | - Yangheshan Yang
- Department of Ecology, School of Life Science, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
| | - Jason M Tylianakis
- Bioprotection Research Centre and Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Christchurch, 8140, New Zealand
| | - Sihai Yang
- Department of Ecology, School of Life Science, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
| | - Yuran Dong
- Department of Ecology, School of Life Science, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
| | - Shucun Sun
- Department of Ecology, School of Life Science, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China.,Chengdu Institute of Biology, Chinese Academy of Sciences, 9 Section 4, Renminnan Rd, Chengdu, 610041, China
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7
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Rosin C, Beals KK, Belovitch MW, Harrison RE, Pendred M, Sullivan MK, Yao N, Poulsen JR. Assessing the effects of elephant foraging on the structure and diversity of an Afrotropical forest. Biotropica 2020. [DOI: 10.1111/btp.12758] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Cooper Rosin
- Nelson Institute for Environmental Studies University of Wisconsin‐Madison Madison Wisconsin
| | - Kendall K. Beals
- Department of Ecology and Evolutionary Biology University of Tennessee Knoxville Tennessee
| | | | | | - Megan Pendred
- Department of Zoology Trinity College Dublin Dublin Ireland
| | - Megan K. Sullivan
- Yale School of Forestry & Environmental Studies Yale University New Haven Connecticut
| | - Nicolas Yao
- Nicholas School of the Environment Duke University Durham North Carolina
| | - John R. Poulsen
- Nicholas School of the Environment Duke University Durham North Carolina
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8
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Spicer ME, Mellor H, Carson WP. Seeing beyond the trees: a comparison of tropical and temperate plant growth forms and their vertical distribution. Ecology 2020; 101:e02974. [PMID: 31944269 DOI: 10.1002/ecy.2974] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 11/10/2019] [Accepted: 12/05/2019] [Indexed: 11/10/2022]
Abstract
Forests are the most diverse and productive terrestrial ecosystems on Earth, so sustainably managing them for the future is a major global challenge. Yet, our understanding of forest diversity relies almost exclusively on the study of trees. Here, we demonstrate unequivocally that other growth forms (shrubs, lianas, herbs, epiphytes) make up the majority of vascular plant species in both tropical and temperate forests. By comparing the relative distribution of species richness among plant growth forms for over 3,400 species in 18 forests in the Americas, we construct the first high-resolution quantification of plant growth form diversity across two ecologically important regions at a near-continental scale. We also quantify the physical distribution of plant species among forest layers, that is, where among the vertical strata plants ultimately live their adult lives, and show that plants are strongly downshifted in temperate forests vs. tropical forests. Our data illustrate a previously unquantified fundamental difference between tropical and temperate forests: what plant growth forms are most speciose, and where they ultimately live in the forest. Recognizing these differences requires that we re-focus ecological research and forest management plans to encompass a broader suite of plant growth forms. This more holistic perspective is essential to conserve global biodiversity.
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Affiliation(s)
- Michelle Elise Spicer
- Department of Biological Sciences, University of Pittsburgh, 4249 Fifth Avenue, Pittsburgh, Pennsylvania, 15260, USA
| | - Hannah Mellor
- Department of Biological Sciences, University of Pittsburgh, 4249 Fifth Avenue, Pittsburgh, Pennsylvania, 15260, USA
| | - Walter P Carson
- Department of Biological Sciences, University of Pittsburgh, 4249 Fifth Avenue, Pittsburgh, Pennsylvania, 15260, USA
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9
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Baldwin JW, Dechmann DKN, Thies W, Whitehead SR. Defensive fruit metabolites obstruct seed dispersal by altering bat behavior and physiology at multiple temporal scales. Ecology 2020; 101:e02937. [PMID: 31750543 DOI: 10.1002/ecy.2937] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 09/04/2019] [Accepted: 10/18/2019] [Indexed: 01/02/2023]
Abstract
The paradoxical presence of toxic chemical compounds in ripe fruits represents a balance between plant enemies and allies: chemical traits can defend seeds against antagonistic herbivores, seed predators, or fungal pathogens, but also can impose costs by repelling mutualistic seed dispersers, although the costs are often difficult to quantify. Seeds gain fitness benefits from traveling far from the parent plant, as they can escape from parental competition and elude specialized herbivores as well as pathogens that accumulate on adult plants. However, seeds are difficult to follow from their parent plant to their final destination. Thus, little is known about the factors that determine seed dispersal distance. We investigated this potential cost of fruit secondary compounds, reduced seed dispersal distance, by combining two data sets from previous work on a Neotropical bat-plant dispersal system (bats in the genus Carollia and plants in the genus Piper). We used data from captive behavioral experiments, which show how amides in ripe fruits of Piper decrease the retention time of seeds and alter food choices. With new analyses, we show that these defensive secondary compounds also delay the time of fruit removal. Next, with a behaviorally annotated bat telemetry data set, we quantified post-feeding movements (i.e., seed dispersal distances). Using generalized additive mixed models we found that seed dispersal distances varied nonlinearly with gut retention times as well as with the time of fruit removal. By interrogating the model predictions, we identified two novel mechanisms by which fruit secondary compounds can impose costs in terms of decreased seed dispersal distances: (1) small-scale reductions in gut retention time and (2) causing fruits to forgo advantageous bat activity peaks that confer high seed dispersal distances.
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Affiliation(s)
- Justin W Baldwin
- Department of Public Health, School of Biostatistics and Epidemiology, University of Massachusetts Amherst, Amherst, Massachusetts, 01003, USA.,Department of Biology, Washington University in St. Louis, St. Louis, Missouri, 63130, USA
| | - Dina K N Dechmann
- Max Planck Institute of Animal Behavior, Radolfzell, 78315, Germany.,Department of Biology, University of Konstanz, Konstanz, 78464, Germany.,Smithsonian Tropical Research Institute, Balboa, Panamá
| | - Wibke Thies
- Gesellschaft für Internationale Zusammenarbeit (GIZ GmbH), Eschborn, 65760, Germany
| | - Susan R Whitehead
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, MC 0390, Blacksburg, Virginia, 24061, USA
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10
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Dynamics of Understory Shrub Biomass in Six Young Plantations of Southern Subtropical China. FORESTS 2017. [DOI: 10.3390/f8110419] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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11
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Massad TJ, Martins de Moraes M, Philbin C, Oliveira C, Cebrian Torrejon G, Fumiko Yamaguchi L, Jeffrey CS, Dyer LA, Richards LA, Kato MJ. Similarity in volatile communities leads to increased herbivory and greater tropical forest diversity. Ecology 2017; 98:1750-1756. [DOI: 10.1002/ecy.1875] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 04/09/2017] [Accepted: 04/18/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Tara J. Massad
- Biology Department; Rhodes College; 2000 North Parkway Memphis Tennessee 38103 USA
- Instituto de Química; Universidade de São Paulo; Av. Prof. Lineu Prestes, 748, Bloco 11 Térreo São Paulo São Paulo 05508-000 Brasil
| | - Marcílio Martins de Moraes
- Instituto de Química; Universidade de São Paulo; Av. Prof. Lineu Prestes, 748, Bloco 11 Térreo São Paulo São Paulo 05508-000 Brasil
| | - Casey Philbin
- Department of Chemistry; University of Nevada; Reno Nevada 89557 USA
| | - Celso Oliveira
- Department of Chemistry; University of Nevada; Reno Nevada 89557 USA
| | - Gerardo Cebrian Torrejon
- Instituto de Química; Universidade de São Paulo; Av. Prof. Lineu Prestes, 748, Bloco 11 Térreo São Paulo São Paulo 05508-000 Brasil
| | - Lydia Fumiko Yamaguchi
- Instituto de Química; Universidade de São Paulo; Av. Prof. Lineu Prestes, 748, Bloco 11 Térreo São Paulo São Paulo 05508-000 Brasil
| | | | - Lee A. Dyer
- Department of Biology; University of Nevada; Reno Nevada 89557 USA
| | - Lora A. Richards
- Department of Biology; University of Nevada; Reno Nevada 89557 USA
| | - Massuo J. Kato
- Instituto de Química; Universidade de São Paulo; Av. Prof. Lineu Prestes, 748, Bloco 11 Térreo São Paulo São Paulo 05508-000 Brasil
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12
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Lemoine NP, Burkepile DE, Parker JD. Insect herbivores increase mortality and reduce tree seedling growth of some species in temperate forest canopy gaps. PeerJ 2017; 5:e3102. [PMID: 28344904 PMCID: PMC5363256 DOI: 10.7717/peerj.3102] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Accepted: 02/17/2017] [Indexed: 11/20/2022] Open
Abstract
Insect herbivores help maintain forest diversity through selective predation on seedlings of vulnerable tree species. Although the role of natural enemies has been well-studied in tropical systems, relatively few studies have experimentally manipulated insect abundance in temperate forests and tracked impacts over multiple years. We conducted a three-year experiment (2012-2014) deterring insect herbivores from seedlings in new treefall gaps in deciduous hardwood forests in Maryland. During this study, we tracked recruitment of all tree seedlings, as well as survivorship and growth of 889 individual seedlings from five tree species: Acer rubrum, Fagus grandifolia, Fraxinus spp., Liriodendron tulipifera, and Liquidambar styraciflua. Insect herbivores had little effect on recruitment of any tree species, although there was a weak indication that recruitment of A. rubrum was higher in the presence of herbivores. Insect herbivores reduced survivorship of L. tulipifera, but had no significant effects on A. rubrum, Fraxinus spp., F. grandifolia, or L. styraciflua. Additionally, insects reduced growth rates of early pioneer species A. rubrum, L. tulipifera, and L. styraciflua, but had little effect on more shade-tolerant species F. grandifolia and Fraxinus spp. Overall, by negatively impacting growth and survivorship of early pioneer species, forest insects may play an important but relatively cryptic role in forest gap dynamics, with potentially interesting impacts on the overall maintenance of diversity.
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Affiliation(s)
- Nathan P. Lemoine
- Department of Biology, Colorado State University, Fort Collins, CO, United States
| | - Deron E. Burkepile
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, United States
| | - John D. Parker
- Smithsonian Environmental Research Center, Edgewater, MD, United States
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Salazar D, Jaramillo A, Marquis RJ. The impact of plant chemical diversity on plant-herbivore interactions at the community level. Oecologia 2016; 181:1199-208. [PMID: 27129320 DOI: 10.1007/s00442-016-3629-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 04/04/2016] [Indexed: 12/11/2022]
Abstract
Understanding the role of diversity in ecosystem processes and species interactions is a central goal of ecology. For plant-herbivore interactions, it has been hypothesized that when plant species diversity is reduced, loss of plant biomass to herbivores increases. Although long-standing, this hypothesis has received mixed support. Increasing plant chemical diversity with increasing plant taxonomic diversity is likely to be important for plant-herbivore interactions at the community level, but the role of chemical diversity is unexplored. Here we assess the effect of volatile chemical diversity on patterns of herbivore damage in naturally occurring patches of Piper (Piperaceae) shrubs in a Costa Rican lowland wet forest. Volatile chemical diversity negatively affected total, specialist, and generalist herbivore damage. Furthermore, there were differences between the effects of high-volatility and low-volatility chemical diversity on herbivore damage. High-volatility diversity reduced specialist herbivory, while low-volatility diversity reduced generalist herbivory. Our data suggest that, although increased plant diversity is expected to reduce average herbivore damage, this pattern is likely mediated by the diversity of defensive compounds and general classes of anti-herbivore traits, as well as the degree of specialization of the herbivores attacking those plants.
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Affiliation(s)
- Diego Salazar
- Department of Integrative Biology, University of California-Berkeley, 1005 Valley Life Sciences Building #3140, Berkeley, CA, 94720-3140, USA. .,Department of Biology and the Whitney R. Harris World Ecology Center, One University Boulevard, University of Missouri-St. Louis, St. Louis, MO, 63121, USA.
| | - Alejandra Jaramillo
- Facultad de Ciencias Basicas, Universidad Militar Nueva Granada, Bogota, Colombia
| | - Robert J Marquis
- Department of Biology and the Whitney R. Harris World Ecology Center, One University Boulevard, University of Missouri-St. Louis, St. Louis, MO, 63121, USA
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14
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Greeney HF, Meneses MR, Hamilton CE, Lichter-Marck E, Mannan RW, Snyder N, Snyder H, Wethington SM, Dyer LA. Trait-mediated trophic cascade creates enemy-free space for nesting hummingbirds. SCIENCE ADVANCES 2015; 1:e1500310. [PMID: 26601258 PMCID: PMC4643763 DOI: 10.1126/sciadv.1500310] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 07/01/2015] [Indexed: 05/20/2023]
Abstract
The indirect effects of predators on nonadjacent trophic levels, mediated through traits of intervening species, are collectively known as trait-mediated trophic cascades. Although birds are important predators in terrestrial ecosystems, clear examples of trait-mediated indirect effects involving bird predators have almost never been documented. Such indirect effects are important for structuring ecological communities and are likely to be negatively impacted by habitat fragmentation, climate change, and other factors that reduce abundance of top predators. We demonstrate that hummingbirds in Arizona realize increased breeding success when nesting in association with hawks. An enemy-free nesting space is created when jays, an important source of mortality for hummingbird nests, alter their foraging behavior in the presence of their hawk predators.
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Affiliation(s)
- Harold F. Greeney
- Yanayacu Biological Station & Center for Creative Studies, Cosanga, Napo, Ecuador
- Department of Biology, University of Nevada, Reno, NV 89557, USA
- Department of Natural Resources, University of Arizona, Tucson, AZ 85721, USA
- Corresponding author. E-mail:
| | - M. Rocio Meneses
- Hummingbird Monitoring Network, P.O. Box 115, Patagonia, AZ 85624, USA
| | - Chris E. Hamilton
- Department of Biology, Trent University, Peterborough, Ontario K9J 7B8, Canada
| | - Eli Lichter-Marck
- Yanayacu Biological Station & Center for Creative Studies, Cosanga, Napo, Ecuador
| | - R. William Mannan
- Department of Natural Resources, University of Arizona, Tucson, AZ 85721, USA
| | | | | | | | - Lee A. Dyer
- Department of Biology, University of Nevada, Reno, NV 89557, USA
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15
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Richards LA, Dyer LA, Forister ML, Smilanich AM, Dodson CD, Leonard MD, Jeffrey CS. Phytochemical diversity drives plant-insect community diversity. Proc Natl Acad Sci U S A 2015; 112:10973-8. [PMID: 26283384 PMCID: PMC4568244 DOI: 10.1073/pnas.1504977112] [Citation(s) in RCA: 149] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
What are the ecological causes and consequences of variation in phytochemical diversity within and between plant taxa? Despite decades of natural products discovery by organic chemists and research by chemical ecologists, our understanding of phytochemically mediated ecological processes in natural communities has been restricted to studies of either broad classes of compounds or a small number of well-characterized molecules. Until now, no studies have assessed the ecological causes or consequences of rigorously quantified phytochemical diversity across taxa in natural systems. Consequently, hypotheses that attempt to explain variation in phytochemical diversity among plants remain largely untested. We use spectral data from crude plant extracts to characterize phytochemical diversity in a suite of co-occurring plants in the tropical genus Piper (Piperaceae). In combination with 20 years of data focused on Piper-associated insects, we find that phytochemical diversity has a direct and positive effect on the diversity of herbivores but also reduces overall herbivore damage. Elevated chemical diversity is associated with more specialized assemblages of herbivores, and the cascading positive effect of phytochemistry on herbivore enemies is stronger as herbivore diet breadth narrows. These results are consistent with traditional hypotheses that predict positive associations between plant chemical diversity, insect herbivore diversity, and trophic specialization. It is clear from these results that high phytochemical diversity not only enhances the diversity of plant-associated insects but also contributes to the ecological predominance of specialized insect herbivores.
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Affiliation(s)
| | - Lee A Dyer
- Biology Department, University of Nevada, Reno, NV 89557
| | | | | | - Craig D Dodson
- Chemistry Department, University of Nevada, Reno, NV 89557
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16
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Sotomayor DA, Lortie CJ. Indirect interactions in terrestrial plant communities: emerging patterns and research gaps. Ecosphere 2015. [DOI: 10.1890/es14-00117.1] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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17
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Early recruitment responses to interactions between frequent fires, nutrients, and herbivory in the southern Amazon. Oecologia 2015; 178:807-17. [PMID: 25676107 DOI: 10.1007/s00442-015-3259-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 01/30/2015] [Indexed: 10/24/2022]
Abstract
Understanding tropical forest diversity is a long-standing challenge in ecology. With global change, it has become increasingly important to understand how anthropogenic and natural factors interact to determine diversity. Anthropogenic increases in fire frequency are among the global change variables affecting forest diversity and functioning, and seasonally dry forest of the southern Amazon is among the ecosystems most affected by such pressures. Studying how fire will impact forests in this region is therefore important for understanding ecosystem functioning and for designing effective conservation action. We report the results of an experiment in which we manipulated fire, nutrient availability, and herbivory. We measured the effects of these interacting factors on the regenerative capacity of the ecotone between humid Amazon forest and Brazilian savanna. Regeneration density, diversity, and community composition were severely altered by fire. Additions of P and N + P reduced losses of density and richness in the first year post-fire. Herbivory was most important just after germination. Diversity was positively correlated with herbivory in unburned forest, likely because fire reduced the number of reproductive individuals. This contrasts with earlier results from the same study system in which herbivory was related to increased diversity after fire. We documented a significant effect of fire frequency; diversity in triennially burned forest was more similar to that in unburned than in annually burned forest, and the community composition of triennially burned forest was intermediate between unburned and annually burned areas. Preventing frequent fires will therefore help reduce losses in diversity in the southern Amazon's matrix of human-altered landscapes.
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Abstract
Understanding variation in resource specialization is important for progress on issues that include coevolution, community assembly, ecosystem processes, and the latitudinal gradient of species richness. Herbivorous insects are useful models for studying resource specialization, and the interaction between plants and herbivorous insects is one of the most common and consequential ecological associations on the planet. However, uncertainty persists regarding fundamental features of herbivore diet breadth, including its relationship to latitude and plant species richness. Here, we use a global dataset to investigate host range for over 7,500 insect herbivore species covering a wide taxonomic breadth and interacting with more than 2,000 species of plants in 165 families. We ask whether relatively specialized and generalized herbivores represent a dichotomy rather than a continuum from few to many host families and species attacked and whether diet breadth changes with increasing plant species richness toward the tropics. Across geographic regions and taxonomic subsets of the data, we find that the distribution of diet breadth is fit well by a discrete, truncated Pareto power law characterized by the predominance of specialized herbivores and a long, thin tail of more generalized species. Both the taxonomic and phylogenetic distributions of diet breadth shift globally with latitude, consistent with a higher frequency of specialized insects in tropical regions. We also find that more diverse lineages of plants support assemblages of relatively more specialized herbivores and that the global distribution of plant diversity contributes to but does not fully explain the latitudinal gradient in insect herbivore specialization.
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19
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Dáttilo W, Dyer L. Canopy Openness Enhances Diversity of Ant-Plant Interactions in the Brazilian Amazon Rain Forest. Biotropica 2014. [DOI: 10.1111/btp.12157] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wesley Dáttilo
- Instituto de Neuroetología; Universidad Veracruzana; Xalapa Veracruz 91190 Mexico
| | - Lee Dyer
- Department of Biology; University of Nevada; Reno NV 89557-0314 U.S.A
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20
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Woody plant phylogenetic diversity mediates bottom–up control of arthropod biomass in species-rich forests. Oecologia 2014; 176:171-82. [DOI: 10.1007/s00442-014-3006-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 06/25/2014] [Indexed: 10/25/2022]
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21
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Salazar D, Kelm DH, Salazar D. Directed seed dispersal of Piper by Carollia perspicillata and its effect on understory plant diversity and folivory. Ecology 2014; 94:2444-53. [PMID: 24400496 DOI: 10.1890/12-1172.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Directed dispersal occurs when seeds are differentially deposited to sites where offspring survivorship is higher than at randomly chosen sites. Traditionally, characteristics of the dispersal target sites that could increase survivorship of the dispersed plants are thought to be intrinsic to the sites. If directed dispersal is constant over extended periods of time, however, it is likely that nonrandom patterns of dispersal could modify the ecological characteristics of the target site in ways that could increase survivorship and fitness of the dispersed plants. Here we report patterns of Piper diversity (richness, equitability, and similarity) and Piper folivory within plots near natural or artificial roosts of Carollia perspicillata vs. similar plots without bat roosts. Plots with bat roosts, both natural and artificial, had significantly higher Piper species diversity. Additionally, we found that plots with a higher Piper species diversity showed less specialist folivory, higher generalist folivory, and lower total herbivore leaf damage than plots with low Piper diversity. Finally, plots with bat roosts also showed less specialist folivory, lower generalist folivory, and lower total folivory when compared to plots without roosts. We propose that long-lasting nonrandom patterns of seed dispersal can change the local ecological characteristics of target sites via changes in plant diversity, and that these changes are likely to reduce the local rates of folivory and, therefore, increase seed and adult plant survivorship.
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Affiliation(s)
- Diego Salazar
- Department of Biology, University of Missouri-St. Louis, 223 Research Building, One University Boulevard, St. Louis, Missouri 63121-4499, USA.
| | - Detlev H Kelm
- Department of Biology, Cognitive Neurobiology, Humboldt University Berlin, Dorotheenstrasse 94, 10117 Berlin, Germany
| | - Diego Salazar
- Department of Biology, Cognitive Neurobiology, Humboldt University Berlin, Dorotheenstrasse 94, 10117 Berlin, Germany
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22
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Tepe EJ, Rodríguez-Castañeda G, Glassmire AE, Dyer LA. Piper kelleyi, a hotspot of ecological interactions and a new species from Ecuador and Peru. PHYTOKEYS 2014; 34:19-32. [PMID: 24596490 PMCID: PMC3941067 DOI: 10.3897/phytokeys.34.6376] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 01/23/2014] [Indexed: 05/21/2023]
Abstract
We describe Piper kelleyi sp. nov., a new species from the eastern Andes of Ecuador and Peru, named in honor of Dr. Walter Almond Kelley. Piper kelleyi is a member of the Macrostachys clade of the genus Piper and supports a rich community of generalist and specialist herbivores, their predators and parasitoids, as well as commensalistic earwigs, and mutualistic ants. This new species was recognized as part of an ecological study of phytochemically mediated relationships between plants, herbivores, predators, and parasitoids. Compared to over 100 other Piper species surveyed, Piper kelleyi supports the largest community of specialist herbivores and parasitoids observed to date.
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Affiliation(s)
- Eric. J. Tepe
- Department of Biological Sciences, University of Cincinnati, 614 Rieveschl Hall, Cincinnati, Ohio 45221, USA
| | - Genoveva Rodríguez-Castañeda
- Department of Integrative Biology, University of Texas at Austin, 1 University Station, Austin, Texas 78712, USA
| | - Andrea E. Glassmire
- Biology Department 0314, University of Nevada Reno, 1664 North Virginia Street, Reno, Nevada 89557, USA
| | - Lee A. Dyer
- Biology Department 0314, University of Nevada Reno, 1664 North Virginia Street, Reno, Nevada 89557, USA
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23
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Zou Y, Sang W, Bai F, Axmacher JC. Relationships between plant diversity and the abundance and α-diversity of predatory ground beetles (Coleoptera: Carabidae) in a mature Asian temperate forest ecosystem. PLoS One 2013; 8:e82792. [PMID: 24376582 PMCID: PMC3869730 DOI: 10.1371/journal.pone.0082792] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 10/29/2013] [Indexed: 12/05/2022] Open
Abstract
A positive relationship between plant diversity and both abundance and diversity of predatory arthropods is postulated by the Enemies Hypothesis, a central ecological top-down control hypothesis. It has been supported by experimental studies and investigations of agricultural and grassland ecosystems, while evidence from more complex mature forest ecosystems is limited. Our study was conducted on Changbai Mountain in one of the last remaining large pristine temperate forest environments in China. We used predatory ground beetles (Coleoptera: Carabidae) as target taxon to establish the relationship between phytodiversity and their activity abundance and diversity. Results showed that elevation was the only variable included in both models predicting carabid activity abundance and α-diversity. Shrub diversity was negatively and herb diversity positively correlated with beetle abundance, while shrub diversity was positively correlated with beetle α-diversity. Within the different forest types, a negative relationship between plant diversity and carabid activity abundance was observed, which stands in direct contrast to the Enemies Hypothesis. Furthermore, plant species density did not predict carabid α-diversity. In addition, the density of herbs, which is commonly believed to influence carabid movement, had little impact on the beetle activity abundance recorded on Changbai Mountain. Our study indicates that in a relatively large and heterogeneous mature forest area, relationships between plant and carabid diversity are driven by variations in environmental factors linked with altitudinal change. In addition, traditional top-down control theories that are suitable in explaining diversity patterns in ecosystems of low diversity appear to play a much less pronounced role in highly complex forest ecosystems.
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Affiliation(s)
- Yi Zou
- UCL Department of Geography, University College London, London, United Kingdom
| | - Weiguo Sang
- The State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- College of Life and Environmental Science, Minzu University of China, Beijing, China
- * E-mail: (WS); (JCA)
| | - Fan Bai
- The State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Jan Christoph Axmacher
- UCL Department of Geography, University College London, London, United Kingdom
- * E-mail: (WS); (JCA)
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24
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Norghauer JM, Newbery DM. Herbivores differentially limit the seedling growth and sapling recruitment of two dominant rain forest trees. Oecologia 2013; 174:459-69. [PMID: 24072438 DOI: 10.1007/s00442-013-2769-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 08/30/2013] [Indexed: 11/26/2022]
Abstract
Resource heterogeneity may influence how plants are attacked and respond to consumers in multiple ways. Perhaps a better understanding of how this interaction might limit sapling recruitment in tree populations may be achieved by examining species' functional responses to herbivores on a continuum of resource availability. Here, we experimentally reduced herbivore pressure on newly established seedlings of two dominant masting trees in 40 canopy gaps, across c. 80 ha of tropical rain forest in central Africa (Korup, Cameroon). Mesh cages were built to protect individual seedlings, and their leaf production and changes in height were followed for 22 months. With more light, herbivores increasingly prevented the less shade-tolerant Microberlinia bisulcata from growing as tall as it could and producing more leaves, indicating an undercompensation. The more shade-tolerant Tetraberlinia bifoliolata was much less affected by herbivores, showing instead near to full compensation for leaf numbers, and a negligible to weak impact of herbivores on its height growth. A stage-matrix model that compared control and caged populations lent evidence for a stronger impact of herbivores on the long-term population dynamics of M. bisulcata than T. bifoliolata. Our results suggest that insect herbivores can contribute to the local coexistence of two abundant tree species at Korup by disproportionately suppressing sapling recruitment of the faster-growing dominant via undercompensation across the light gradient created by canopy disturbances. The functional patterns we have documented here are consistent with current theory, and, because gap formations are integral to forest regeneration, they may be more widely applicable in other tropical forest communities. If so, the interaction between life-history and herbivore impact across light gradients may play a substantial role in tree species coexistence.
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Affiliation(s)
- Julian M Norghauer
- Institute of Plant Sciences, University of Bern, 21 Altenbergrain, 3013, Bern, Switzerland,
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25
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Sedio BE, Ostling AM. How specialised must natural enemies be to facilitate coexistence among plants? Ecol Lett 2013; 16:995-1003. [PMID: 23773378 DOI: 10.1111/ele.12130] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 12/09/2012] [Accepted: 04/28/2013] [Indexed: 11/29/2022]
Abstract
The Janzen-Connell hypothesis proposes that plant interactions with host-specific antagonists can impair the fitness of locally abundant species and thereby facilitate coexistence. However, insects and pathogens that associate with multiple hosts may mediate exclusion rather than coexistence. We employ a simulation model to examine the effect of enemy host breadth on plant species richness and defence community structure, and to assess expected diversity maintenance in example systems. Only models in which plant enemy similarity declines rapidly with defence similarity support greater species richness than models of neutral drift. In contrast, a wide range of enemy host breadths result in spatial dispersion of defence traits, at both landscape and local scales, indicating that enemy-mediated competition may increase defence-trait diversity without enhancing species richness. Nevertheless, insect and pathogen host associations in Panama and Papua New Guinea demonstrate a potential to enhance plant species richness and defence-trait diversity comparable to strictly specialised enemies.
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Affiliation(s)
- Brian E Sedio
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA.
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26
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Ibanez S, Bison M, Lavorel S, Moretti M. Herbivore species identity mediates interspecific competition between plants. COMMUNITY ECOL 2013. [DOI: 10.1556/comec.14.2013.1.5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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27
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Massad TJ, Balch JK, Davidson EA, Brando PM, Mews CL, Porto P, Quintino RM, Vieira SA, Junior BHM, Trumbore SE. Interactions between repeated fire, nutrients, and insect herbivores affect the recovery of diversity in the southern Amazon. Oecologia 2012; 172:219-29. [PMID: 23053239 DOI: 10.1007/s00442-012-2482-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2011] [Accepted: 09/12/2012] [Indexed: 11/25/2022]
Abstract
Surface fires burn extensive areas of tropical forests each year, altering resource availability, biotic interactions, and, ultimately, plant diversity. In transitional forest between the Brazilian cerrado (savanna) and high stature Amazon forest, we took advantage of a long-term fire experiment to establish a factorial study of the interactions between fire, nutrient availability, and herbivory on early plant regeneration. Overall, five annual burns reduced the number and diversity of regenerating stems. Community composition changed substantially after repeated fires, and species common in the cerrado became more abundant. The number of recruits and their diversity were reduced in the burned area, but burned plots closed to herbivores with nitrogen additions had a 14 % increase in recruitment. Diversity of recruits also increased up to 50 % in burned plots when nitrogen was added. Phosphorus additions were related to an increase in species evenness in burned plots open to herbivores. Herbivory reduced seedling survival overall and increased diversity in burned plots when nutrients were added. This last result supports our hypothesis that positive relationships between herbivore presence and diversity would be strongest in treatments that favor herbivory--in this case herbivory was higher in burned plots which were initially lower in diversity. Regenerating seedlings in less diverse plots were likely more apparent to herbivores, enabling increased herbivory and a stronger signal of negative density dependence. In contrast, herbivores generally decreased diversity in more species rich unburned plots. Although this study documents complex interactions between repeated burns, nutrients, and herbivory, it is clear that fire initiates a shift in the factors that are most important in determining the diversity and number of recruits. This change may have long-lasting effects as the forest progresses through succession.
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Affiliation(s)
- Tara Joy Massad
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Str 10, 07745 Jena, Germany.
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28
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Abstract
Increases in species diversity and density from higher to lower latitudes are well documented. Nevertheless, the consequences of these changes in diversity for structuring ecological communities and influencing biotic evolution are largely unknown. It is widely believed that this increase in species diversity is associated with increased intensity of ecological interactions closer to the equator. For plant-herbivore interactions in particular, the predictions are that, at lower latitudes, plants will be attacked by more individual herbivores, more herbivore species, and more specialized herbivores and, therefore, will suffer greater damage. We used a large-scale latitudinal transect from Mexico to Bolivia to quantify changes in leaf damage, diversity, and abundance of lepidopteran larvae on two widely distributed host species of the genus Piper (Piperaceae). We show that both density and species richness of herbivores were highest at the equator and decreased with increasing latitude, both northward and southward. Contrary to expectation, however, this increase in herbivore diversity was attributable to the addition of generalist not specialist species. Finally, and again contrary to expectation, the increase in herbivore density with decreasing latitude did not produce a corresponding damage gradient. We propose that the lack of a latitudinal concordance between increases in herbivore density and diversity with decreasing latitude, and the resulting herbivore damage, supports the hypothesis of better plant antiherbivore defenses at lower latitudes. Furthermore, the changes in the relative abundance of generalist vs. specialist species suggest that the nature of the selective pressure is intrinsically different between higher and lower latitudes.
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29
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Clark CJ, Poulsen JR, Levey DJ. Vertebrate herbivory impacts seedling recruitment more than niche partitioning or density-dependent mortality. Ecology 2012; 93:554-64. [PMID: 22624210 DOI: 10.1890/11-0894.1] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In tropical forests, resource-based niches and density-dependent mortality are mutually compatible mechanisms that can act simultaneously to limit seedling populations. Differences in the strengths of these mechanisms will determine their roles in maintaining species coexistence. In the first assessment of these mechanisms in a Congo Basin forest, we quantified their relative strengths and tested the extent to which density-dependent mortality is driven by the distance-dependent behavior of seed and seedling predators predicted by the Janzen-Connell hypothesis. We conducted a large-scale seed addition experiment for five randomly selected tropical tree species, caging a subset of seed addition quadrats against vertebrate predators. We then developed models to assess the mechanisms that determine seedling emergence (three months after seed addition) and survival (two years after seed addition). As predicted, both niche differentiation and density-dependent mortality limited seedling recruitment, but predation had the strongest effects on seedling emergence and survival. Seedling species responded differently to naturally occurring environmental variation among sites, including variation in light levels and soil characteristics, supporting predictions of niche-based theories of tropical tree species coexistence. The addition of higher densities of seeds into quadrats initially led to greater seedling emergence, but survival to two years decreased with seed density. Seed and seedling predation reduced recruitment below levels maintained by density-dependent mortality, an indication that predators largely determine the population size of tree seedlings. Seedling recruitment was unrelated to the distance to or density of conspecific adult trees, suggesting that recruitment patterns are generated by generalist vertebrate herbivores rather than the specialized predators predicted by the Janzen-Connell hypothesis. If the role of seed and seedling predation in limiting seedling recruitment is a general phenomenon, then the relative abundances of tree species might largely depend on species-specific adaptations to avoid, survive, and recover from damage induced by vertebrate herbivores. Likewise, population declines of herbivorous vertebrate species (many of which are large and hunted) may trigger shifts in species composition of tropical forests.
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Affiliation(s)
- C J Clark
- Nicholas School of the Environment, Duke University, P.O. Box 90328, Durham, North Carolina 27708, USA.
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Gilbert GS, Magarey R, Suiter K, Webb CO. Evolutionary tools for phytosanitary risk analysis: phylogenetic signal as a predictor of host range of plant pests and pathogens. Evol Appl 2012; 5:869-78. [PMID: 23346231 PMCID: PMC3552404 DOI: 10.1111/j.1752-4571.2012.00265.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 03/28/2012] [Indexed: 11/28/2022] Open
Abstract
Assessing risk from a novel pest or pathogen requires knowing which local plant species are susceptible. Empirical data on the local host range of novel pests are usually lacking, but we know that some pests are more likely to attack closely related plant species than species separated by greater evolutionary distance. We use the Global Pest and Disease Database, an internal database maintained by the United States Department of Agriculture Animal and Plant Health Inspection Service - Plant Protection and Quarantine Division (USDA APHIS-PPQ), to evaluate the strength of the phylogenetic signal in host range for nine major groups of plant pests and pathogens. Eight of nine groups showed significant phylogenetic signal in host range. Additionally, pests and pathogens with more known hosts attacked a phylogenetically broader range of hosts. This suggests that easily obtained data - the number of known hosts and the phylogenetic distance between known hosts and other species of interest - can be used to predict which plant species are likely to be susceptible to a particular pest. This can facilitate rapid assessment of risk from novel pests and pathogens when empirical host range data are not yet available and guide efficient collection of empirical data for risk evaluation.
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Affiliation(s)
- Gregory S Gilbert
- Environmental Studies Department, University of California Santa Cruz, CA, USA ; Smithsonian Tropical Research Institute Balboa, Ancón, Panama
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Rodríguez-Castañeda G, Forkner RE, Tepe EJ, Gentry GL, Dyer LA. Weighing Defensive and Nutritive Roles of Ant Mutualists Across a Tropical Altitudinal Gradient. Biotropica 2010. [DOI: 10.1111/j.1744-7429.2010.00700.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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