1
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Case SB, Postelli K, Drake DR, Vizentin-Bugoni J, Foster JT, Sperry JH, Kelley JP, Tarwater CE. Introduced galliforms as seed predators and dispersers in Hawaiian forests. Biol Invasions 2022. [DOI: 10.1007/s10530-022-02830-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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2
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Yelenik S, Rose E, Paxton EH. Trophic interactions and feedbacks maintain intact and degraded states of Hawaiian tropical forests. Ecosphere 2022. [DOI: 10.1002/ecs2.3884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Stephanie Yelenik
- U.S. Geological Survey Pacific Island Ecosystems Research Center Hawaiʻi National Park Hilo Hawaiʻi USA
| | - Eli Rose
- U.S. Geological Survey Pacific Island Ecosystems Research Center Hawaiʻi National Park Hilo Hawaiʻi USA
| | - Eben H. Paxton
- U.S. Geological Survey Pacific Island Ecosystems Research Center Hawaiʻi National Park Hilo Hawaiʻi USA
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3
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Cordero S, Gálvez F, Fontúrbel FE. Multiple Anthropogenic Pressures Lead to Seed Dispersal Collapse of the Southernmost Palm Jubaea chilensis. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.719566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Seed dispersal is a critical process for plant reproduction and regeneration. Successful recruitment depends on pre- and post-dispersal processes that complete a seed’s journey until becoming a new plant. However, anthropogenic stressors may disrupt the seed dispersal process at some stages, collapsing plant regeneration and hampering its long-term persistence. The Chilean palm tree Jubaea chilensis is the southernmost and the only non-tropical palm species, which currently relies on the scatter-hoarding rodent Octodon degus for seed dispersal. We assessed seed fate by measuring predation and dispersal rates through experimental fieldwork in the Palmar de Ocoa site (located within La Campana National Park) and the Palmar El Salto. We also used previous reports on seed harvest and seedling herbivory to depict the whole J. chilensis seed dispersal process and assess the relative importance of different anthropogenic pressures. We asked the following questions: (1) What is the effect of human harvesting on J. chilensis recruitment? (2) Do native and exotic rodents predate J. chilensis seeds in the same way? and (3) Does post-dispersal herbivory matter? We found that J. chilensis fruits are harvested for human consumption, reducing pre-dispersal available seeds by removing about 23 tons per season. Then, post-dispersal seeds at the Ocoa palm grove are heavily predated by exotic (Rattus rattus) and native (Octodon spp.) rodents; only 8.7% of the seeds are effectively dispersed by Octodon degus. At Palmar El Salto, 100% of the seeds were predated by Rattus rattus, precluding further analysis. Finally, 70% of the seedlings were consumed by exotic herbivores (mainly rabbits), resulting in a success rate of 1.81%. Only 7.9% of the surviving seedlings become infantile plants (4 year-old). Our assessment suggests that J. chilensis has aging populations with very few young individuals in disturbed sites to replace the old ones. For those reasons, we suggest increasing its conservation category to critically endangered as land-use change is rapidly fragmenting and shrinking the extant J. chilensis populations. We urge to take urgent actions to protect this relict palm, which otherwise may go extinct in the next decades.
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Cordell S, Bardwell-Jones C, Ostertag R, Uowolo A, DiManno N. Species Home-Making in Ecosystems: Toward Place-Based Ecological Metrics of Belonging. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.726571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Globalization has undeniably impacted the Earth’s ecosystems, but it has also influenced how we think about natural systems. Three fourths of the world’s forests are now altered by human activity, which challenges our concepts of native ecosystems. The dichotomies of pristine vs. disturbed as well as our view of native and non-native species, have blurred; allowing us to acknowledge new paradigms about how humans and nature interact. We now understand that the use of militaristic language to define the perceived role of a plant species is holding us back from the fact that novel systems (new combinations of all species) can often provide valuable ecosystem services (i.e., water, carbon, nutrients, cultural, and recreation) for creatures (including humans). In reality, ecosystems exist in a gradient from native to intensely managed – and “non-nativeness” is not always a sign of a species having negative effects. In fact, there are many contemporary examples of non-native species providing critical habitat for endangered species or preventing erosion in human-disturbed watersheds. For example, of the 8,000–10,000 non-native species introduced to Hawai‘i, less than 10% of these are self-sustaining and 90 of those pose a danger to native biota and are considered invasive. In this paper, we explore the native/non-native binary, the impacts of globalization and the political language of invasion through the lens of conservation biology and sociology with a tropical island perspective. This lens gives us the opportunity to offer a place-based approach toward the use of empirical observation of novel species interactions that may help in evaluating management strategies that support biodiversity and ecosystem services. Finally, we offer a first attempt at conceptualizing a site-specific approach to develop “metrics of belonging” within an ecosystem.
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5
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Barnagaud J, Brockerhoff EG, Mossion R, Dufour P, Pavoine S, Deconchat M, Barbaro L. Trait‐habitat associations explain novel bird assemblages mixing native and alien species across New Zealand landscapes. DIVERS DISTRIB 2021. [DOI: 10.1111/ddi.13432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
| | - Eckehard G. Brockerhoff
- Scion (New Zealand Forest Research Institute) Christchurch New Zealand
- Swiss Federal Research Institute WSL Birmensdorf Switzerland
| | - Raphaël Mossion
- CEFE, Univ Montpellier CNRS, EPHE‐PSL University, IRD Montpellier France
| | - Paul Dufour
- Laboratoire d’Écologie Alpine CNRS Univ. Savoie Mont BlancCNRSLECAUniv. Grenoble Alpes Grenoble France
| | - Sandrine Pavoine
- Centre d'Ecologie et des Sciences de la Conservation (CESCO) Muséum national d'Histoire naturelle (MNHN) Centre National de la Recherche Scientifique (CNRS)Sorbonne Université Paris France
| | - Marc Deconchat
- DYNAFOR INRA Université de Toulouse Castanet‐Tolosan France
| | - Luc Barbaro
- Centre d'Ecologie et des Sciences de la Conservation (CESCO) Muséum national d'Histoire naturelle (MNHN) Centre National de la Recherche Scientifique (CNRS)Sorbonne Université Paris France
- DYNAFOR INRA Université de Toulouse Castanet‐Tolosan France
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6
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Fruit and seed traits of native and invasive plant species in Hawai‘i: implications for seed dispersal by non-native birds. Biol Invasions 2021. [DOI: 10.1007/s10530-021-02473-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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7
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Ecological correlates of species' roles in highly invaded seed dispersal networks. Proc Natl Acad Sci U S A 2021; 118:2009532118. [PMID: 33431649 DOI: 10.1073/pnas.2009532118] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ecosystems with a mix of native and introduced species are increasing globally as extinction and introduction rates rise, resulting in novel species interactions. While species interactions are highly vulnerable to disturbance, little is known about the roles that introduced species play in novel interaction networks and what processes underlie such roles. Studying one of the most extreme cases of human-modified ecosystems, the island of O'ahu, Hawaii, we show that introduced species there shape the structure of seed dispersal networks to a greater extent than native species. Although both neutral and niche-based processes influenced network structure, niche-based processes played a larger role, despite theory predicting neutral processes to be predominantly important for islands. In fact, ecological correlates of species' roles (morphology, behavior, abundance) were largely similar to those in native-dominated networks. However, the most important ecological correlates varied with spatial scale and trophic level, highlighting the importance of examining these factors separately to unravel processes determining species contributions to network structure. Although introduced species integrate into interaction networks more deeply than previously thought, by examining the mechanistic basis of species' roles we can use traits to identify species that can be removed from (or added to) a system to improve crucial ecosystem functions, such as seed dispersal.
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8
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Coux C, Donoso I, Tylianakis JM, García D, Martínez D, Dehling DM, Stouffer DB. Tricky partners: native plants show stronger interaction preferences than their exotic counterparts. Ecology 2020; 102:e03239. [PMID: 33125718 DOI: 10.1002/ecy.3239] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 08/29/2020] [Accepted: 09/14/2020] [Indexed: 11/08/2022]
Abstract
In ecological networks, neutral predictions suggest that species' interaction frequencies are proportional to their relative abundances. Deviations from neutral predictions thus correspond to interaction preferences (when positive) or avoidances (when negative), driven by nonneutral (e.g., niche-based) processes. Exotic species interact with many partners with which they have not coevolved, and it remains unclear whether this systematically influences the strength of neutral processes on interactions, and how these interaction-level differences scale up to entire networks. To fill this gap, we compared interactions between plants and frugivorous birds at nine forest sites in New Zealand varying in the relative abundance and composition of native and exotic species, with independently sampled data on bird and plant abundances from the same sites. We tested if the strength and direction of interaction preferences differed between native and exotic species. We further evaluated whether the performance of neutral predictions at the site level was predicted by the proportion of exotic interactions in each network from both bird and plant perspectives, and the species composition in each site. We found that interactions involving native plants deviated more strongly from neutral predictions than did interactions involving exotics. This "pickiness" of native plants could be detrimental in a context of global biotic homogenization where they could be increasingly exposed to novel interactions with neutrally interacting mutualists. However, the realization of only a subset of interactions in different sites compensated for the neutrality of interactions involving exotics, so that neutral predictions for whole networks did not change systematically with the proportion of exotic species or species composition. Therefore, the neutral and niche processes that underpin individual interactions may not scale up to entire networks. This shows that seemingly simplistic neutral assumptions entail complex processes and can provide valuable understanding of community assembly or invasion dynamics.
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Affiliation(s)
- Camille Coux
- Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
| | - Isabel Donoso
- Senckenberg Biodiversity and Climate Research Centre (BiK-F), Senckenberganlage 25, Frankfurt (Main), 60325, Germany.,Departamento Biología de Organismos y Sistemas, Unidad Mixta de Investigación en Biodiversidad (UMIB, CSIC-UO-PA), Universidad de Oviedo, Oviedo, 33071, Spain
| | - Jason M Tylianakis
- Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
| | - Daniel García
- Departamento Biología de Organismos y Sistemas, Unidad Mixta de Investigación en Biodiversidad (UMIB, CSIC-UO-PA), Universidad de Oviedo, Oviedo, 33071, Spain
| | - Daniel Martínez
- Departamento Biología de Organismos y Sistemas, Unidad Mixta de Investigación en Biodiversidad (UMIB, CSIC-UO-PA), Universidad de Oviedo, Oviedo, 33071, Spain
| | - D Matthias Dehling
- Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
| | - Daniel B Stouffer
- Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
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9
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Case SB, Tarwater CE. Functional traits of avian frugivores have shifted following species extinction and introduction in the Hawaiian Islands. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13670] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Samuel B. Case
- Department of Zoology and Physiology and Program in Ecology University of Wyoming Laramie WY USA
| | - Corey E. Tarwater
- Department of Zoology and Physiology and Program in Ecology University of Wyoming Laramie WY USA
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10
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Infestation by pollination-disrupting alien ants varies temporally and spatially and is worsened by alien plant invasion. Biol Invasions 2020. [DOI: 10.1007/s10530-020-02272-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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11
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Traveset A, Escribano‐Avila G, Gómez JM, Valido A. Conflicting selection on
Cneorum tricoccon
(Rutaceae) seed size caused by native and alien seed dispersers. Evolution 2019; 73:2204-2215. [DOI: 10.1111/evo.13852] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 09/03/2019] [Accepted: 09/05/2019] [Indexed: 01/02/2023]
Affiliation(s)
- Anna Traveset
- Global Change Research GroupInstitut Mediterrani d'Estudis Avançats (CSIC‐UIB) 07190 Esporles Mallorca Balearic Islands Spain
| | - Gema Escribano‐Avila
- Global Change Research GroupInstitut Mediterrani d'Estudis Avançats (CSIC‐UIB) 07190 Esporles Mallorca Balearic Islands Spain
| | - José María Gómez
- Departamento Ecología Funcional y EvolutivaEstación Experimental de Zonas Áridas (EEZA‐CSIC) 04120 Almería Spain
| | - Alfredo Valido
- Instituto de Productos Naturales y Agrobiología (IPNA‐CSIC) 38206 La Laguna Tenerife Islas Canarias Spain
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12
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MacDonald SE, Ward MP, Sperry JH. Manipulating social information to promote frugivory by birds on a Hawaiian Island. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2019; 29:e01963. [PMID: 31247121 DOI: 10.1002/eap.1963] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 05/04/2019] [Accepted: 05/28/2019] [Indexed: 06/09/2023]
Abstract
Animals across a range of taxa use social information when foraging. Fruit-eating vertebrates are no exception and use social information to find fruit, which may ultimately affect plant populations via seed dispersal. In many systems, mutualistic relationships between fruiting plants and frugivores are critical to maintain ecosystem functioning, especially in the tropics. On the island of O'ahu, Hawaii, USA, all native, fruit-eating birds are extinct and several plant species are experiencing reduced recruitment likely due to a lack of seed dispersal. Over the years, numerous bird species, many of which are frugivorous, have been introduced to the island. Yet, introduced birds may not recognize native fruits as a resource and social information may be needed for introduced frugivores to target and feed on native fruits. We investigated whether social information, in the form of broadcasted bird vocalizations, of introduced birds could increase visitations and more importantly frugivory on focal fruiting plants. We also tested whether the visitation rates of introduced bird species to focal plants were influenced by conspecific and/or heterospecific vocalizations. We conducted 80 playback experiments at native and introduced fruiting plants, and compared responses to silent control periods. Four times as many frugivores were detected and 10 times more frugivory events were recorded at plants with broadcasted vocalizations compared to control periods. The Japanese White-eye (Zosterops japonicus) exhibited the strongest response to both conspecific and heterospecific playbacks. White-eyes also consumed the most fruit from the widest array of plant species during trials. Introduced birds that use social information and readily identify novel resources may more effectively colonize new areas. We suggest that the White-eye's use of social information may help to support their robust population on O'ahu. Ecosystems throughout the world are affected by the loss of mutualistic relationships, many of which provide valuable ecological services. As humans continue to modify environments, novel conservation approaches may be required to maintain important ecological functions. The use of social information to facilitate frugivory may not only be important in Hawaii, but in other tropical systems where key frugivorous species are lost or abundances have been reduced.
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Affiliation(s)
- S E MacDonald
- Department of Natural Resources and Environmental Science, University of Illinois at Urbana-Champaign, 1102 S. Goodwin Avenue, Urbana, Illinois, 61801, USA
| | - M P Ward
- Department of Natural Resources and Environmental Science, University of Illinois at Urbana-Champaign, 1102 S. Goodwin Avenue, Urbana, Illinois, 61801, USA
| | - J H Sperry
- Department of Natural Resources and Environmental Science, University of Illinois at Urbana-Champaign, 1102 S. Goodwin Avenue, Urbana, Illinois, 61801, USA
- Engineer Research and Development Center, P.O. Box 9005, Champaign, Illinois, 61826, USA
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13
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Berger-Tal O, Saltz D. Invisible barriers: anthropogenic impacts on inter- and intra-specific interactions as drivers of landscape-independent fragmentation. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180049. [PMID: 31352896 PMCID: PMC6710564 DOI: 10.1098/rstb.2018.0049] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Anthropogenically induced fragmentation constitutes a major threat to biodiversity. Presently, conservation research and actions focus predominantly on fragmentation caused directly by physical transformation of the landscape (e.g. deforestation, agriculture, urbanization, roads, etc.). While there is no doubt that landscape features play a key role in fragmenting populations or enhancing connectivity, fragmentation may also come about by processes other than the transformation of the landscape and which may not be readily visible. Such landscape-independent fragmentation (LIF) usually comes about when anthropogenic disturbance alters the inter- and intra-specific interactions among and within species. LIF and its drivers have received little attention in the scientific literature and in the management of wildlife populations. We discuss three major classes of LIF processes and their relevance for the conservation and management of species and habitats: (i) interspecific dispersal dependency, in which populations of species that rely on other species for transport and propagation become fragmented as the transporting species declines; (ii) interspecific avoidance induction, where species are excluded from habitats and corridors owing to interspecific interactions resulting from anthropogenically induced changes in community structure (e.g. exclusions by increased predation pressure); and (iii) intraspecific behavioural divergence, where populations become segregated owing to anthropogenically induced behavioural differentiation among them. This article is part of the theme issue ‘Linking behaviour to dynamics of populations and communities: application of novel approaches in behavioural ecology to conservation'.
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Affiliation(s)
- Oded Berger-Tal
- Mitrani Department of Desert Ecology, Ben-Gurion University of the Negev, 8499000 Midreshet Ben Gurion, Israel
| | - David Saltz
- Mitrani Department of Desert Ecology, Ben-Gurion University of the Negev, 8499000 Midreshet Ben Gurion, Israel
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14
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Gleditsch JM, Sperry JH. Rapid morphological change of nonnative frugivores on the Hawaiian island of O'ahu*. Evolution 2019; 73:1456-1465. [DOI: 10.1111/evo.13744] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 03/30/2019] [Accepted: 04/02/2019] [Indexed: 01/15/2023]
Affiliation(s)
- Jason M. Gleditsch
- Department of Natural Resources and Environmental Sciences University of Illinois at Urbana‐Champaign Urbana Illinois 61801
| | - Jinelle H. Sperry
- Department of Natural Resources and Environmental Sciences University of Illinois at Urbana‐Champaign Urbana Illinois 61801
- Engineer Research and Development Center Champaign Illinois 61826
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15
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Vizentin-Bugoni J, Tarwater CE, Foster JT, Drake DR, Gleditsch JM, Hruska AM, Kelley JP, Sperry JH. Structure, spatial dynamics, and stability of novel seed dispersal mutualistic networks in Hawaiʻi. Science 2019; 364:78-82. [DOI: 10.1126/science.aau8751] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 11/29/2018] [Accepted: 03/05/2019] [Indexed: 11/02/2022]
Abstract
Increasing rates of human-caused species invasions and extinctions may reshape communities and modify the structure, dynamics, and stability of species interactions. To investigate how such changes affect communities, we performed multiscale analyses of seed dispersal networks on Oʻahu, Hawaiʻi. Networks consisted exclusively of novel interactions, were largely dominated by introduced species, and exhibited specialized and modular structure at local and regional scales, despite high interaction dissimilarity across communities. Furthermore, the structure and stability of the novel networks were similar to native-dominated communities worldwide. Our findings suggest that shared evolutionary history is not a necessary process for the emergence of complex network structure, and interaction patterns may be highly conserved, regardless of species identity and environment. Introduced species can quickly become well integrated into novel networks, making restoration of native ecosystems more challenging than previously thought.
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16
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Bartel RD, Sheppard JL, Lovas-Kiss Á, Green AJ. Endozoochory by mallard in New Zealand: what seeds are dispersed and how far? PeerJ 2018; 6:e4811. [PMID: 29844967 PMCID: PMC5970560 DOI: 10.7717/peerj.4811] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 04/30/2018] [Indexed: 11/20/2022] Open
Abstract
In Europe and North America waterfowl are major dispersers of aquatic and terrestrial plants, but in New Zealand their role has yet to be investigated. Mallards were introduced to New Zealand in the late 1800s, and today they are the most abundant and widespread waterfowl in the country. To assess seed dispersal, we radiomarked 284 female mallards from two study sites during the pre-breeding (June-August) and breeding (August-December) periods in 2014-2015, and examined movements that occurred within 24, 48 or 72 h when seed dispersal by endozoochory is considered likely. During June and July 2015, we collected 29 faecal samples from individual female mallards during radiomarking and 24 samples from mallard flocks. We recovered 69 intact seeds from the faecal samples and identified 12 plant taxa. Of the plant seeds identified and dispersed by mallards in this study, 40% were members of the Asteraceae family, nine plant species were alien to New Zealand, and the indigenous-status of three unidentified taxa could not be determined. Two taxa (and 9% of seeds) were germinated following gut passage: an unidentified Asteraceae and Solanum nigrum. During the pre-breeding and breeding periods, movement of females within 24 h averaged 394 m (SD = 706 m) and 222 m (SD = 605 m) respectively, with maximum distances of 3,970 m and 8,028 m. Maxima extended to 19,230 m within 48 h. Most plant species recorded are generally assumed to be self-dispersed or dispersed by water; mechanisms that provide a much lower maximum dispersal distance than mallards. The ability of mallards to disperse viable seeds up to 19 km within 48 h suggests they have an important and previously overlooked role as vectors for a variety of wetland or grassland plant species in New Zealand.
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Affiliation(s)
- Riley D Bartel
- Clayton H. Riddell Faculty of Environment, Earth, and Resources, University of Manitoba, Winnipeg, Canada
| | - Jennifer L Sheppard
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Ádám Lovas-Kiss
- Department of Botany, University of Debrecen, Debrecen, Hungary
| | - Andy J Green
- Department of Wetland Ecology, Estación Biológica de Doñana, EBD-CSIC, Seville, Spain
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17
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Gawel AM, Rogers HS, Miller RH, Kerr AM. Contrasting ecological roles of non-native ungulates in a novel ecosystem. ROYAL SOCIETY OPEN SCIENCE 2018; 5:170151. [PMID: 29765619 PMCID: PMC5936884 DOI: 10.1098/rsos.170151] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 03/21/2018] [Indexed: 06/01/2023]
Abstract
Conservation has long focused on preserving or restoring pristine ecosystems. However, understanding and managing novel ecosystems has grown in importance as they outnumber pristine ecosystems worldwide. While non-native species may be neutral or detrimental in pristine ecosystems, it is possible that even notorious invaders could play beneficial or mixed roles in novel ecosystems. We examined the effects of two long-established non-native species-Philippine deer (Rusa marianna) and feral pigs (Sus scrofa)-in Guam, Micronesia, where native vertebrate frugivores are functionally absent leaving forests devoid of seed dispersers. We compared the roles of deer and pigs on seedling survival, seed dispersal and plant community structure in limestone karst forests. Deer, even at low abundances, had pronounced negative impacts on forest communities by decreasing seedling and vine abundance. By contrast, pigs showed no such relationship. Also, many viable seeds were found in pig scats, whereas few were found in deer scats, suggesting that pigs, but not deer, provide an ecosystem function-seed dispersal-that has been lost from Guam. Our study presents a discrepancy between the roles of two non-native species that are traditionally managed as a single entity, suggesting that ecological function, rather than identity as a non-native, may be more important to consider in managing novel systems.
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Affiliation(s)
- Ann Marie Gawel
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA
| | - Haldre S. Rogers
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA
| | - Ross H. Miller
- College of Natural and Applied Sciences, University of Guam, UOG Station, Mangilao, GU, USA
| | - Alexander M. Kerr
- Marine Laboratory, University of Guam, UOG Station, Mangilao, GU, USA
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18
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Pejchar L, Gallo T, Hooten MB, Daily GC. Predicting effects of large-scale reforestation on native and exotic birds. DIVERS DISTRIB 2018. [DOI: 10.1111/ddi.12723] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Liba Pejchar
- Department of Fish, Wildlife and Conservation Biology; Colorado State University; Fort Collins CO USA
| | - Travis Gallo
- Urban Wildlife Institute; Department of Conservation and Science; Lincoln Park Zoo; Chicago IL USA
| | - Mevin B. Hooten
- Colorado Cooperative Fish and Wildlife Research Unit; U.S. Geological Survey; Fort Collins CO USA
- Department of Fish, Wildlife and Conservation Biology; Colorado State University; Fort Collins CO USA
- Department of Statistics; Colorado State University; Fort Collins CO USA
| | - Gretchen C. Daily
- Department of Biology; Center for Conservation Biology and Woods Institute; Stanford University; Stanford CA USA
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19
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Kaushik M, Pejchar L, Crampton LH. Potential disruption of seed dispersal in the absence of a native Kauai thrush. PLoS One 2018; 13:e0191992. [PMID: 29381764 PMCID: PMC5790251 DOI: 10.1371/journal.pone.0191992] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 01/15/2018] [Indexed: 11/18/2022] Open
Abstract
Hawaii has experienced a catastrophic decline in frugivorous native birds coupled with the introduction of non-native species. Puaiohi (Myadestes palmeri), a critically endangered thrush, is the sole extant native songbird capable of dispersing fleshy fruited plants in the rainforest of Kauai island, Hawaii. As this species has declined to occupy a small proportion of its original range, a suite of largely omnivorous non-native birds have been introduced to this region, including the common and widespread Japanese White-eye (Zosterops japonicus). This reshuffling of the bird community could have long-term implications for plant community composition if introduced birds incompletely replace the ecological role of native species. The objective of this study was to evaluate the potential consequences of the local extirpation of Puaiohi for seed dispersal. Specifically, we compared the diet of Puaiohi and Japanese White-eye, vegetation characteristics, and seed rain at sites with and without Puaiohi in the Na Pali-Kona Forest Reserve on the island of Kauai. We found high overlap in the composition of seeds consumed by the two bird species, but differences in the characteristics of seeds consumed; Japanese White-eye appeared more likely to consume smaller seeded species compared with Puaiohi. Sites with Puaiohi received substantially higher seed rain during the study period, despite no significant differences in overall fruit abundance. Our results suggest that non-native birds are unlikely to completely replace the seed dispersal services provided by Puaiohi. If Puaohi continue to be rare and range restricted, we predict a shift in plant community composition through an increase in non-native and small-seeded plants, and possible dispersal failure of other native species. Our findings lend further support to efforts to conserve Puaiohi across its current and former range, and to consider introductions to other suitable areas to ensure the persistence not only of the species and but also its functional role in Hawaii's montane ecosystems.
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Affiliation(s)
- Monica Kaushik
- Wildlife Institute of India, Chandrabani, Dehardun, India
| | - Liba Pejchar
- Department of Fish, Wildlife and Conservation Biology, Colorado State University, Fort Collins, CO, United States of America
| | - Lisa H Crampton
- Hawaii Department of Land and Natural Resources and University of Hawaii Manoa, Kaua'i Forest Bird Recovery Project, Hanapepe, HI, United States of America
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Wolfe JD, Ralph CJ, Wiegardt A. Bottom-up processes influence the demography and life-cycle phenology of Hawaiian bird communities. Ecology 2017; 98:2885-2894. [PMID: 28779523 DOI: 10.1002/ecy.1981] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 07/20/2017] [Accepted: 07/28/2017] [Indexed: 11/08/2022]
Abstract
Changes in climate can indirectly regulate populations at higher trophic levels by influencing the availability of food resources in the lower reaches of the food web. As such, species that rely on fruit and nectar food resources may be particularly sensitive to these bottom-up perturbations due to the strength of their trophic linkages with climatically-influenced plants. To measure the influence of climatically-mediated, bottom-up processes, we used climate, bird capture, bird count, and plant phenology data from the Big Island of Hawaii to construct a series of structural equation and abundance models. Our results suggest that fruit and nectar-eating birds arrange life cycle events around climatically-influenced food resources, while some of these same food resources also influence seasonal patterns of abundance. This trend was particularly strong for two native nectarivores, 'I'iwi and 'Apapane, where we found that the dissimilar timing of molting and breeding activity was associated with peak abundance of the two most common flowers at our study site which, in turn, were each driven by dissimilar climatic cues. Given the rapidly changing Hawaiian climate, we suggest that determining behavioral plasticity, or evolutionary capacity of birds to mitigate changes in climatically-influenced food resources, should be recognized as a future research priority.
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Affiliation(s)
- Jared D Wolfe
- U.S.D.A Forest Service, Pacific Southwest Research Station, Arcata, California, 95521, USA.,Wildlife Department, Humboldt State University, Arcata, California, 95521, USA.,Klamath Bird Observatory, Ashland, Oregon, 97520, USA
| | - C John Ralph
- U.S.D.A Forest Service, Pacific Southwest Research Station, Arcata, California, 95521, USA.,Klamath Bird Observatory, Ashland, Oregon, 97520, USA
| | - Andrew Wiegardt
- U.S.D.A Forest Service, Pacific Southwest Research Station, Arcata, California, 95521, USA.,Wildlife Department, Humboldt State University, Arcata, California, 95521, USA
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21
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Gleditsch JM, Hruska AM, Foster JT. Connecting Resource Tracking by Frugivores to Temporal Variation in Seed Dispersal Networks. Front Ecol Evol 2017. [DOI: 10.3389/fevo.2017.00098] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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22
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Paxton EH, Yelenik SG, Borneman TE, Rose ET, Camp RJ, Kendall SJ. Rapid colonization of a Hawaiian restoration forest by a diverse avian community. Restor Ecol 2017. [DOI: 10.1111/rec.12540] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Eben H. Paxton
- U.S. Geological Survey, Pacific Island Ecosystems Research Center, PO Box 44; Hawai′i National Park HI 96718 U.S.A
| | - Stephanie G. Yelenik
- U.S. Geological Survey, Pacific Island Ecosystems Research Center, PO Box 44; Hawai′i National Park HI 96718 U.S.A
| | - Tracy E. Borneman
- Hawai′i Cooperative Studies Unit; University of Hawai′i at Hilo; Hilo HI 96720 U.S.A
| | - Eli T. Rose
- U.S. Geological Survey, Pacific Island Ecosystems Research Center, PO Box 44; Hawai′i National Park HI 96718 U.S.A
| | - Richard J. Camp
- Hawai′i Cooperative Studies Unit; University of Hawai′i at Hilo; Hilo HI 96720 U.S.A
| | - Steve J. Kendall
- U.S. Fish and Wildlife Service; Hakalau Forest National Wildlife Refuge; Hilo HI 96720 U.S.A
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23
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Pereira PF, Godinho C, Vila-Viçosa MJ, Mota PG, Lourenço R. Competitive advantages of the red-billed leiothrix (Leiothrix lutea) invading a passerine community in Europe. Biol Invasions 2017. [DOI: 10.1007/s10530-016-1364-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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24
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Gallien L, Altermatt F, Wiemers M, Schweiger O, Zimmermann NE. Invasive plants threaten the least mobile butterflies in Switzerland. DIVERS DISTRIB 2016. [DOI: 10.1111/ddi.12513] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- Laure Gallien
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL; CH-8903 Birmensdorf Switzerland
- Centre for Invasion Biology; Department of Botany & Zoology; Stellenbosch University; 7602 Matieland South Africa
| | - Florian Altermatt
- Department of Aquatic Ecology; Eawag, Swiss Federal Institute of Aquatic Science and Technology; Überlandstrasse 133 CH-8600 Dübendorf Switzerland
- Department of Evolutionary Biology and Environmental Studies; University of Zurich; Winterthurerstr. 190 CH-8057 Zürich Switzerland
| | - Martin Wiemers
- UFZ - Helmholtz Centre for Environmental Research; Theodor-Lieser-Str. 4 06120 Halle Germany
| | - Oliver Schweiger
- UFZ - Helmholtz Centre for Environmental Research; Theodor-Lieser-Str. 4 06120 Halle Germany
| | - Niklaus E. Zimmermann
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL; CH-8903 Birmensdorf Switzerland
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25
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Comparative effects of native frugivores and introduced rodents on seed germination in New-Caledonian rainforest plants. Biol Invasions 2016. [DOI: 10.1007/s10530-016-1284-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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26
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Assessing the Value of Novel Habitats to Snail Kites through Foraging Behavior and Nest Survival. JOURNAL OF FISH AND WILDLIFE MANAGEMENT 2016. [DOI: 10.3996/022016-jfwm-008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Abstract
Novel ecosystems arise for a variety of reasons, most notably from the introduction of nonnative species. Understanding the interactions between traditional habitats, novel habitats, and species of conservation interest is important when planning successful conservation strategies. In the United States, the snail kite Rostrhamus sociabilis plumbeus is a federally endangered species whose population in Florida has undergone declines within the past decade. While studying the foraging behavior of breeding snail kites on Lake Tohopekaliga (Lake Toho), we discovered the unexpected use of disturbed ephemeral wetlands adjacent to the lake. These wetlands represent a novel habitat for snail kites; they would not have been viable foraging areas prior to the introduction of the exotic island apple snail Pomacea maculata. By examining the differences between snail kite behavior in traditional and novel habitats, we were able to identify some characteristics of novel habitats that may be important in determining their value to snail kites. The novel wetland areas were highly attractive to snail kites, likely because of the high snail capture rates. The survival of snail kite nests occurring within the novel areas appeared to be similar to that of nests occurring in more traditional, nearby areas on Lake Toho. However, whether or not snail kites used novel habitats as nesting areas appeared to be dependent upon water depth and availability of nesting substrate within these areas. The snail kites' dynamic use of the novel habitat demonstrates both the value of a novel ecosystem and the importance of traditional habitats to a species of conservation concern.
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27
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Twardochleb LA, Olden JD. Non‐native Chinese mystery snail (
Bellamya chinensis
) supports consumers in urban lake food webs. Ecosphere 2016. [DOI: 10.1002/ecs2.1293] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Laura A. Twardochleb
- School of Aquatic and Fishery Sciences University of Washington 1122 NE Boat Street Seattle Washington 98195 USA
| | - Julian D. Olden
- School of Aquatic and Fishery Sciences University of Washington 1122 NE Boat Street Seattle Washington 98195 USA
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28
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Yelenik SG. Linking dominant Hawaiian tree species to understory development in recovering pastures via impacts on soils and litter. Restor Ecol 2016. [DOI: 10.1111/rec.12377] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Stephanie G. Yelenik
- U.S. Geological Survey, Pacific Island Ecosystems Research Center; Crater Rim Drive Hawai‘i National Park HI 96718 U.S.A
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29
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Aslan CE, Sikes BA, Gedan KB. Research on mutualisms between native and non-native partners can contribute critical ecological insights. NEOBIOTA 2015. [DOI: 10.3897/neobiota.26.8837] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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30
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Pejchar L. Introduced birds incompletely replace seed dispersal by a native frugivore. AOB PLANTS 2015; 7:plv072. [PMID: 26139183 PMCID: PMC4526755 DOI: 10.1093/aobpla/plv072] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 06/01/2015] [Indexed: 05/28/2023]
Abstract
The widespread loss of native species and the introduction of non-native species has important consequences for island ecosystems. Non-native species may or may not functionally replace the role of native species in ecological processes such as seed dispersal. Although the majority of Hawaii's native plants require bird-mediated seed dispersal, only one native frugivore, Omao (Myadestes obscurus), persists in sufficient numbers to fill this functional role. Omao are restricted to less than half their original range, but two introduced frugivores are abundant throughout Hawaii. Given large-scale extinctions on islands, it is important to understand whether introduced birds serve as functional replacements or whether the absence of native frugivores alters plant communities. To assess seed dispersal by native and introduced birds, seed rain, vegetation characteristics, bird diet, density and habitat use were measured at three sites with Omao and three sites without Omao on Hawaii Island. The diet of native and introduced birds overlapped substantially, but Omao dispersed a variety of native species (n = 6) relatively evenly. In contrast, introduced birds dispersed an invasive species and fewer native species (n = 4), and >90 % of seeds dispersed by introduced birds were from two ubiquitous small-seeded species. Seed rain was significantly greater and more species rich at sites with Omao. These findings suggest that patterns of seed dispersal are altered following the local extinction of a native island frugivore. To more directly evaluate the relative roles of native and introduced frugivores in ecological processes, future studies could include reintroducing Omao to a suitable habitat within its historic range, or novel introductions to nearby islands where closely related species are now extinct. In an era of widespread extinction and invasion of island ecosystems, understanding the consequences of novel animal assemblages for processes like seed dispersal will be critical for maintaining diverse and self-regenerating plant communities.
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Affiliation(s)
- Liba Pejchar
- Department of Fish, Wildlife and Conservation Biology, Colorado State University, Fort Collins, CO 80523, USA
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31
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Wallach AD, Ripple WJ, Carroll SP. Novel trophic cascades: apex predators enable coexistence. Trends Ecol Evol 2015; 30:146-53. [DOI: 10.1016/j.tree.2015.01.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 01/05/2015] [Accepted: 01/06/2015] [Indexed: 01/01/2023]
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32
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Traveset A, Richardson DM. Mutualistic Interactions and Biological Invasions. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2014. [DOI: 10.1146/annurev-ecolsys-120213-091857] [Citation(s) in RCA: 258] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mutualisms structure ecosystems and mediate their functioning. They also enhance invasions of many alien species. Invasions disrupt native mutualisms, often leading to population declines, reduced biodiversity, and altered ecosystem functioning. Focusing on three main types of mutualisms (pollination, seed dispersal, and plant-microbial symbioses) and drawing on examples from different ecosystems and from species- and community-level studies, we review the key mechanisms whereby such positive interactions mediate invasions and are in turn influenced by invasions. High interaction generalization is “the norm” in most systems, allowing alien species to infiltrate recipient communities. We identify traits that influence invasiveness (e.g., selfing capacity in plants, animal behavioral traits) or invasibility (e.g., partner choice in mycorrhizas/rhizobia) through mutualistic interactions. Mutualistic disruptions due to invasions are pervasive, and subsequent cascading effects are also widespread. Ecological networks provide a useful framework for predicting tipping points for community collapse in response to invasions and other synergistic drivers of global change.
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Affiliation(s)
- Anna Traveset
- Mediterranean Institute of Advanced Studies, E07190 Esporles, Mallorca, Balearic Islands, Spain
| | - David M. Richardson
- Centre for Invasion Biology, Department of Botany and Zoology, University of Stellenbosch, Matieland 7602, South Africa
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33
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Aslan CE, Zavaleta ES, Tershy B, Croll D, Robichaux RH. Imperfect replacement of native species by non-native species as pollinators of endemic Hawaiian plants. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2014; 28:478-488. [PMID: 24372761 DOI: 10.1111/cobi.12193] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 07/02/2013] [Indexed: 06/03/2023]
Abstract
Native plant species that have lost their mutualist partners may require non-native pollinators or seed dispersers to maintain reproduction. When natives are highly specialized, however, it appears doubtful that introduced generalists will partner effectively with them. We used visitation observations and pollination treatments (experimental manipulations of pollen transfer) to examine relationships between the introduced, generalist Japanese White-eye (Zosterops japonicus) and 3 endemic Hawaiian plant species (Clermontia parviflora, C. montis-loa, and C. hawaiiensis). These plants are characterized by curved, tubular flowers, apparently adapted for pollination by curve-billed Hawaiian honeycreepers. Z. japonicus were responsible for over 80% of visits to flowers of the small-flowered C. parviflora and the midsize-flowered C. montis-loa. Z. japonicus-visited flowers set significantly more seed than did bagged flowers. Z. japonicus also demonstrated the potential to act as an occasional Clermontia seed disperser, although ground-based frugivory by non-native mammals likely dominates seed dispersal. The large-flowered C. hawaiiensis received no visitation by any birds during observations. Unmanipulated and bagged C. hawaiiensis flowers set similar numbers of seeds. Direct examination of Z. japonicus and Clermontia morphologies suggests a mismatch between Z. japonicus bill morphology and C. hawaiiensis flower morphology. In combination, our results suggest that Z. japonicus has established an effective pollination relationship with C. parviflora and C. montis-loa and that the large flowers of C. hawaiiensis preclude effective visitation by Z. japonicus.
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Affiliation(s)
- Clare E Aslan
- Department of Environmental Studies, University of California, Santa Cruz, CA, 95064, U.S.A.; Conservation Education and Science Department, Arizona-Sonora Desert Museum, Tucson, AZ, 85743, U.S.A..
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34
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Wu JX, Delparte DM, Hart PJ. Movement Patterns of a Native and Non-native Frugivore in Hawaii and Implications for Seed Dispersal. Biotropica 2014. [DOI: 10.1111/btp.12087] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Joanna X. Wu
- Tropical Conservation Biology and Environmental Sciences; University of Hawaii at Hilo; 200 W. Kawili St Hilo HI 96720 U.S.A
| | - Donna M. Delparte
- Department of Geosciences; Idaho State University; 921 S. 8th Ave Stop 8072 Pocatello ID 83209 U.S.A
| | - Patrick J. Hart
- Tropical Conservation Biology and Environmental Sciences; University of Hawaii at Hilo; 200 W. Kawili St Hilo HI 96720 U.S.A
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35
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Rogers AM, Chown SL. Novel ecosystems support substantial avian assemblages: the case of invasive alien
A
cacia
thickets. DIVERS DISTRIB 2013. [DOI: 10.1111/ddi.12123] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Andrew M. Rogers
- Department of Botany and Zoology Centre for Invasion Biology Stellenbosch University Private Bag X1 Matieland 7602 South Africa
| | - Steven L. Chown
- Department of Botany and Zoology Centre for Invasion Biology Stellenbosch University Private Bag X1 Matieland 7602 South Africa
- School of Biological Sciences Monash University Clayton Vic. 3800 Australia
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36
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Cole RJ, Litton CM. Vegetation response to removal of non-native feral pigs from Hawaiian tropical montane wet forest. Biol Invasions 2013. [DOI: 10.1007/s10530-013-0508-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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37
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38
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Aslan CE, Zavaleta ES, Croll D, Tershy B. Effects of native and non-native vertebrate mutualists on plants. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2012; 26:778-789. [PMID: 22809395 DOI: 10.1111/j.1523-1739.2012.01885.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Extinctions can leave species without mutualist partners and thus potentially reduce their fitness. In cases where non-native species function as mutualists, mutualism disruption associated with species' extinction may be mitigated. To assess the effectiveness of mutualist species with different origins, we conducted a meta-analysis in which we compared the effectiveness of pollination and seed-dispersal functions of native and non-native vertebrates. We used data from 40 studies in which a total of 34 non-native vertebrate mutualists in 20 geographic locations were examined. For each plant species, opportunistic non-native vertebrate pollinators were generally less effective mutualists than native pollinators. When native mutualists had been extirpated, however, plant seed set and seedling performance appeared elevated in the presence of non-native mutualists, although non-native mutualists had a negative overall effect on seed germination. These results suggest native mutualists may not be easily replaced. In some systems researchers propose taxon substitution or the deliberate introduction of non-native vertebrate mutualists to reestablish mutualist functions such as pollination and seed dispersal and to rescue native species from extinction. Our results also suggest that in places where all native mutualists are extinct, careful taxon substitution may benefit native plants at some life stages.
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Affiliation(s)
- Clare E Aslan
- Department of Environmental Studies, University of California-Santa Cruz, Santa Cruz, CA 95064, USA.
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Culliney S, Pejchar L, Switzer R, Ruiz-Gutierrez V. Seed dispersal by a captive corvid: the role of the 'Alalā (Corvus hawaiiensis) in shaping Hawai'i's plant communities. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2012; 22:1718-1732. [PMID: 23092010 DOI: 10.1890/11-1613.1] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Species loss can lead to cascading effects on communities, including the disruption of ecological processes such as seed dispersal. The endangered 'Alalā (Corvus hawaiiensis), the largest remaining species of native Hawaiian forest bird, was once common in mesic and dry forests on the Big Island of Hawai'i, but today it exists solely in captivity. Prior to its extinction in the wild, the 'Alalā may have helped to establish and maintain native Hawaiian forest communities by dispersing seeds of a wide variety of native plants. In the absence of 'Alalā, the structure and composition of Hawai'i's forests may be changing, and some large-fruited plants may be dispersal limited, persisting primarily as ecological anachronisms. We fed captive 'Alalā a variety of native fruits, documented behaviors relating to seed dispersal, and measured the germination success of seeds that passed through the gut of 'Alalā relative to the germination success of seeds in control groups. 'Alalā ate and carried 14 native fruits and provided germination benefits to several species by ingesting their seeds. Our results suggest that some plants rely heavily on 'Alalā for these services. In captivity, juvenile birds displayed seed dispersal behaviors more often than adult birds for most fruiting plants in our study. We introduced captive 'Alalā to two large-fruited, dry-forest plants, not previously recorded as 'Alalā food resources, but which may once have been part of their natural diet. The seed dispersal behavior that 'Alalā displayed toward these species supports the inclusion of dry and mesic forests in 'Alalā habitat restoration plans and adds weight to the idea that plant dispersal limitation may contribute to the rarity of these plants. Our study provides evidence that 'Alalā have the capacity to play a vital role in maintaining the diversity of fruiting plants in native Hawaiian forests through seed dispersal and enhanced seed germination, thus adding greater urgency to efforts to restore 'Alalā to their former range.
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Affiliation(s)
- Susan Culliney
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, 1474 Campus Delivery, Fort Collins, Colorado 80523, USA.
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40
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Large-scale rodent control reduces pre- and post-dispersal seed predation of the endangered Hawaiian lobeliad, Cyanea superba subsp. superba (Campanulaceae). Biol Invasions 2012. [DOI: 10.1007/s10530-012-0280-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
At a time when plant species are experiencing increasing challenges from climate change, land-use change, harvesting and invasive species, dispersal has become a very important aspect of plant conservation. Seed dispersal by animals is particularly important because some animals disperse seeds to suitable sites in a directed fashion. Our review has two aims: (i) to highlight the various ways plant dispersal by animals can be affected by current anthropogenic change and (ii) to show the important role of plant and (particularly) animal physiology in shaping seed-dispersal interactions. We argue that large-bodied seed dispersers may be particularly important for plant conservation because seed dispersal of large-seeded plants is often more specialized and because large-bodied animals are targeted by human exploitation and have smaller population sizes. We further argue that more specialized seed-dispersal systems on island ecosystems might be particularly at risk from climate change both owing to small population sizes involved but also owing to the likely thermal specialization, particularly on tropical islands. More generally, the inherent vulnerability of seed-dispersal mutualisms to disruption driven by environmental change (as well as their ubiquity) demands that we continue to improve our understanding of their conservation physiology.
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Affiliation(s)
- Graeme D Ruxton
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
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Traveset A, González-Varo JP, Valido A. Long-term demographic consequences of a seed dispersal disruption. Proc Biol Sci 2012; 279:3298-303. [PMID: 22628466 DOI: 10.1098/rspb.2012.0535] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The loss or decline of vertebrate frugivores can limit the regeneration of plants that depend on them. However, empirical evidence is showing that this is still very scarce, as functionally equivalent species may contribute to maintain the mutualistic interaction. Here, we investigated the long-term consequences of the extinction of frugivorous lizards on the population persistence of a Mediterranean relict shrub Cneorum tricoccon (Cneoraceae). We examined the demographic parameters among 26 insular and mainland populations, which encompass the entire plant distributional range, comparing populations with lizards with those in which these are extinct, but in which alien mammals currently act as seed dispersers. Plant recruitment was found to be higher on island populations with lizards than on those with mammals, and the long-term effects of the native disperser's loss were found in all vital phases of plant regeneration. The study thus gives evidence of the cascading effects of human-induced changes in ecosystems, showing how the disruption of native ecological processes can lead to species regression and, in the long term, even to local extinctions.
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Affiliation(s)
- Anna Traveset
- Instituto Mediterráneo de Estudios Avanzados (CSIC-UIB), Miquel Marqués 21, 07190 Esporles, Mallorca, Balearic Islands, Spain.
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43
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Aslan C, Rejmanek M. Native fruit traits may mediate dispersal competition between native and non-native plants. NEOBIOTA 2012. [DOI: 10.3897/neobiota.12.2357] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Cole RJ, Litton CM, Koontz MJ, Loh RK. Vegetation Recovery 16 Years after Feral Pig Removal from a Wet Hawaiian Forest. Biotropica 2012. [DOI: 10.1111/j.1744-7429.2011.00841.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rebecca J. Cole
- Department of Natural Resources and Environmental Management; University of Hawaii at Manoa; Honolulu; Hawaii; 96822; U.S.A
| | - Creighton M. Litton
- Department of Natural Resources and Environmental Management; University of Hawaii at Manoa; Honolulu; Hawaii; 96822; U.S.A
| | - Michael J. Koontz
- Department of Natural Resources and Environmental Management; University of Hawaii at Manoa; Honolulu; Hawaii; 96822; U.S.A
| | - Rhonda K. Loh
- Division of Resources Management; Hawaii Volcanoes National Park; National Park Service; Hawaii National Park; Hawaii Volcanoes NP, Hawaii; 96718; U.S.A
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Westcott DA, Fletcher CS. Biological invasions and the study of vertebrate dispersal of plants: Opportunities and integration. ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY 2011. [DOI: 10.1016/j.actao.2011.04.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Martínez OJA. Flooding and profuse flowering result in high litterfall in novelSpathodea campanulataforests in northern Puerto Rico. Ecosphere 2011. [DOI: 10.1890/es11-00165.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Schlaepfer MA, Sax DF, Olden JD. The potential conservation value of non-native species. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2011; 25:428-37. [PMID: 21342267 DOI: 10.1111/j.1523-1739.2010.01646.x] [Citation(s) in RCA: 289] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Non-native species can cause the loss of biological diversity (i.e., genetic, species, and ecosystem diversity) and threaten the well-being of humans when they become invasive. In some cases, however, they can also provide conservation benefits. We examined the ways in which non-native species currently contribute to conservation objectives. These include, for example, providing habitat or food resources to rare species, serving as functional substitutes for extinct taxa, and providing desirable ecosystem functions. We speculate that non-native species might contribute to achieving conservation goals in the future because they may be more likely than native species to persist and provide ecosystem services in areas where climate and land use are changing rapidly and because they may evolve into new and endemic taxa. The management of non-native species and their potential integration into conservation plans depends on how conservation goals are set in the future. A fraction of non-native species will continue to cause biological and economic damage, and substantial uncertainty surrounds the potential future effects of all non-native species. Nevertheless, we predict the proportion of non-native species that are viewed as benign or even desirable will slowly increase over time as their potential contributions to society and to achieving conservation objectives become well recognized and realized.
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Affiliation(s)
- Martin A Schlaepfer
- State University of New York, College of Environmental Science and Forestry, Syracuse, NY 13210, USA.
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Chimera CG, Drake DR. Patterns of Seed Dispersal and Dispersal Failure in a Hawaiian Dry Forest Having Only Introduced Birds. Biotropica 2010. [DOI: 10.1111/j.1744-7429.2009.00610.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Davis NE, O'Dowd DJ, Mac Nally R, Green PT. Invasive ants disrupt frugivory by endemic island birds. Biol Lett 2009; 6:85-8. [PMID: 19755533 DOI: 10.1098/rsbl.2009.0655] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Biological invasions can alter direct and indirect interactions between species, generating far-reaching changes in ecological networks that affect key ecological functions. We used model and real fruit assays to show that the invasion and formation of high-density supercolonies by the yellow crazy ant (YCA), Anoplolepis gracilipes, disrupt frugivory by endemic birds on Christmas Island, Indian Ocean. The overall handling rates of model fruits by birds were 2.2-2.4-fold lower in ant-invaded than in uninvaded rainforest, and pecking rates by two bird species declined by 2.6- and 4.5-fold, respectively. YCAs directly interfered with frugivory; their experimental exclusion from fruiting displays increased fruit handling threefold to sixfold, compounding indirect effects of ant invasion on resources and habitat structure that influence bird abundances and behaviours. This invasive ant, whose high densities are sustained through mutualism with introduced scale insects, rapidly decreases fruit handling by endemic island birds and may erode a key ecological function, seed dispersal. Because most other invasive ant species form expansive, high-density supercolonies that depend in part on association with hemipteran mutualists, the effects that we report here on avian frugivore-plant associations may emerge across their introduced ranges.
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Affiliation(s)
- Naomi E Davis
- Australian Centre for Biodiversity, School of Biological Sciences, Monash University, , Victoria 3800, Australia
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