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Gauthey A, Backes D, Balland J, Alam I, Maher DT, Cernusak LA, Duke NC, Medlyn BE, Tissue DT, Choat B. The Role of Hydraulic Failure in a Massive Mangrove Die-Off Event. Front Plant Sci 2022; 13:822136. [PMID: 35574083 PMCID: PMC9094047 DOI: 10.3389/fpls.2022.822136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 03/25/2022] [Indexed: 06/15/2023]
Abstract
Between late 2015 and early 2016, more than 7,000 ha of mangrove forest died along the coastline of the Gulf of Carpentaria, in northern Australia. This massive die-off was preceded by a strong 2015/2016 El Niño event, resulting in lower precipitation, a drop in sea level and higher than average temperatures in northern Australia. In this study, we investigated the role of hydraulic failure in the mortality and recovery of the dominant species, Avicennia marina, 2 years after the mortality event. We measured predawn water potential (Ψpd) and percent loss of stem hydraulic conductivity (PLC) in surviving individuals across a gradient of impact. We also assessed the vulnerability to drought-induced embolism (Ψ50) for the species. Areas with severe canopy dieback had higher native PLC (39%) than minimally impacted areas (6%), suggesting that hydraulic recovery was ongoing. The high resistance of A. marina to water-stress-induced embolism (Ψ50 = -9.6 MPa), indicates that severe water stress (Ψpd < -10 MPa) would have been required to cause mortality in this species. Our data indicate that the natural gradient of water-stress enhanced the impact of El Niño, leading to hydraulic failure and mortality in A. marina growing on severely impacted (SI) zones. It is likely that lowered sea levels and less frequent inundation by seawater, combined with lower inputs of fresh water, high evaporative demand and high temperatures, led to the development of hyper-salinity and extreme water stress during the 2015/16 summer.
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Affiliation(s)
- Alice Gauthey
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- Plant Ecology Research Laboratory PERL, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Diana Backes
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Jeff Balland
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Iftakharul Alam
- College of Science and Engineering, James Cook University, Cairns, QLD, Australia
| | - Damien T. Maher
- Faculty of Science and Engineering, Southern Cross University, Lismore, NSW, Australia
| | - Lucas A. Cernusak
- College of Science and Engineering, James Cook University, Cairns, QLD, Australia
| | - Norman C. Duke
- TropWATER Centre, James Cook University, Townsville, QLD, Australia
| | - Belinda E. Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - David T. Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
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Petit S, Scanlon AT, Naikatini A, Pukala T, Schumann R. A novel bat pollination system involving obligate flower corolla removal has implications for global Dillenia conservation. PLoS One 2022; 17:e0262985. [PMID: 35113889 PMCID: PMC8812880 DOI: 10.1371/journal.pone.0262985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 01/10/2022] [Indexed: 11/19/2022] Open
Abstract
The Dilleniaceae is known to produce nectarless flowers pollinated by bees, but the fact that bats ingest Dillenia biflora pollen led us to question pollination assumptions for these trees. We aimed to identify the pollinators of D. biflora, check for nectar presence, and investigate potential for cleistogamy and global prevalence of this pollination system. We examined aspects of the pollination of D. biflora on two Fijian islands using video recordings, direct observations, hand pollination, measurements (flowers, bite marks, nectar), and monitoring. The flowers, receptive for one night, contained copious nectar and had permanently closed globose corollas that required removal by bats for pollination. All the 101 flowers that retained their corolla died and did not produce seeds by cleistogamy. The bat Notopteris macdonaldi was well adapted to corolla removal. Keeping corollas closed until bats manipulate the nectar-rich flowers is a beneficial strategy in high-rainfall environments with many flower parasites. We propose to name a pollination system reliant exclusively on bats “chiropteropisteusis.” From clues in the literature, other species in the geographical range of Dillenia are probably chiropteropisunous. Chiropteropisteusis should be investigated in the Old-World range of Dillenia, many species of which are threatened. The remarkable “fall” of the entire corolla observed by an earlier botanist for several species in the genus is most likely attributable to bats. This discovery has important implications for the conservation of bat-dependent trees and their associated fauna, particularly considering the high level of threat faced by flying-foxes globally.
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Affiliation(s)
- Sophie Petit
- UniSA STEM, University of South Australia, Mawson Lakes, South Australia, Australia
- NatureFiji-MareqetiViti, Suva, Fiji Islands
- Kangaroo Island Research Station, Dudley West, South Australia, Australia
- * E-mail:
| | - Annette T. Scanlon
- UniSA STEM, University of South Australia, Mawson Lakes, South Australia, Australia
| | - Alivereti Naikatini
- South Pacific Regional Herbarium and Biodiversity Centre, Institute of Applied Sciences, University of the South Pacific, Private Bag, Laucala Campus, Suva, Fiji Islands
| | - Tara Pukala
- School of Physical Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Russell Schumann
- Kangaroo Island Research Station, Dudley West, South Australia, Australia
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Hill P, Shams F, Burridge CP, Wapstra E, Ezaz T. Differences in Homomorphic Sex Chromosomes Are Associated with Population Divergence in Sex Determination in Carinascincus ocellatus (Scincidae: Lygosominae). Cells 2021; 10:291. [PMID: 33535518 PMCID: PMC7912723 DOI: 10.3390/cells10020291] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/28/2021] [Accepted: 01/28/2021] [Indexed: 01/09/2023] Open
Abstract
Sex determination directs development as male or female in sexually reproducing organisms. Evolutionary transitions in sex determination have occurred frequently, suggesting simple mechanisms behind the transitions, yet their detail remains elusive. Here we explore the links between mechanisms of transitions in sex determination and sex chromosome evolution at both recent and deeper temporal scales (<1 Myr; ~79 Myr). We studied a rare example of a species with intraspecific variation in sex determination, Carinascincus ocellatus, and a relative, Liopholis whitii, using c-banding and mapping of repeat motifs and a custom Y chromosome probe set to identify the sex chromosomes. We identified both unique and conserved regions of the Y chromosome among C. ocellatus populations differing in sex determination. There was no evidence for homology of sex chromosomes between C. ocellatus and L. whitii, suggesting independent evolutionary origins. We discuss sex chromosome homology between members of the subfamily Lygosominae and propose links between sex chromosome evolution, sex determination transitions, and karyotype evolution.
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Affiliation(s)
- Peta Hill
- Discipline of Biological Sciences, University of Tasmania, Private Bag 5, Sandy Bay, TAS 7000, Australia; (C.P.B.); (E.W.)
| | - Foyez Shams
- Institute for Applied Ecology, University of Canberra, Bruce, ACT 2601, Australia; (F.S.); (T.E.)
| | - Christopher P. Burridge
- Discipline of Biological Sciences, University of Tasmania, Private Bag 5, Sandy Bay, TAS 7000, Australia; (C.P.B.); (E.W.)
| | - Erik Wapstra
- Discipline of Biological Sciences, University of Tasmania, Private Bag 5, Sandy Bay, TAS 7000, Australia; (C.P.B.); (E.W.)
| | - Tariq Ezaz
- Institute for Applied Ecology, University of Canberra, Bruce, ACT 2601, Australia; (F.S.); (T.E.)
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Lavery TH, Posala CK, Tasker EM, Fisher DO. Ecological generalism and resilience of tropical island mammals to logging: A 23 year test. Glob Chang Biol 2020; 26:3285-3293. [PMID: 32239613 DOI: 10.1111/gcb.15038] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 01/12/2020] [Accepted: 01/25/2020] [Indexed: 06/11/2023]
Abstract
Tropical forest disturbance is a key driver of global biodiversity decline. On continents, the effects of logging are greatest on endemic species, presumably because disturbance is more likely to cover narrower distributions (the "cookie cutter" model). Islands hold disproportionate biodiversity, and are subject to accelerating biotic homogenization, where specialist endemics are lost while generalists persist. We tested responses of tropical island mammals to logging at multiple spatial scales, using a long-term experimental test in a Pacific archipelago. The most widely distributed ecological generalists did not decline after logging, and we detected no overall changes in relative abundance or species diversity. However, endemics with small ranges did decline in response to logging. The least mobile and most range-restricted species declined even at the smallest spatial scale, supporting the cookie cutter model for sedentary species, and suggesting that habitat change due to selective logging is contributing to biotic homogenization on islands.
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Affiliation(s)
- Tyrone H Lavery
- School of Biological Sciences, The University of Queensland, St Lucia, Qld, Australia
- Negaunee Integrative Research Center, Field Museum of Natural History, Chicago, IL, USA
| | - Corzzierrah K Posala
- School of Biological & Chemical Sciences, University of the South Pacific, Suva, Fiji Islands
| | - Elizabeth M Tasker
- Ecosystem Management Science Branch, Science Division, New South Wales Office of Environment and Heritage, Sydney South, NSW, Australia
- Mammal Section, Australian Museum, Sydney, NSW, Australia
| | - Diana O Fisher
- School of Biological Sciences, The University of Queensland, St Lucia, Qld, Australia
- Mammal Section, Australian Museum, Sydney, NSW, Australia
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Nilsen AR, Teasdale SE, Guy PL, Summerfield TC, Orlovich DA. Fungal diversity in canopy soil of silver beech, Nothofagus menziesii (Nothofagaceae). PLoS One 2020; 15:e0227860. [PMID: 31978185 PMCID: PMC6980614 DOI: 10.1371/journal.pone.0227860] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 01/01/2020] [Indexed: 01/16/2023] Open
Abstract
Adventitious roots in canopy soils associated with silver beech (Nothofagus menziesii Hook.f. (Nothofagaceae)) form ectomycorrhizal associations. We investigated the extent to which canopy ectomycorrhizal communities contribute to overall diversity of ectomycorrhizal fungi associated with silver beech. Hyphal ingrowth bags were buried for 12 months in canopy and terrestrial soils of five trees at one site. We used amplicon sequencing of the nuclear ribosomal internal transcribed spacer 2 region (ITS2) to assess diversity of both ectomycorrhizal and non-ectomycorrhizal OTUs in hyphal ingrowth bags. There was a significant difference in ectomycorrhizal fungal community diversity between the terrestrial and canopy hyphal ingrowth bag communities. Ectomycorrhizal community composition of the terrestrial and canopy environments was also significantly different. Some ectomycorrhizal taxa were significantly differentially represented in either the terrestrial or canopy environment. The hyphal ingrowth bags also accumulated non-ectomycorrhizal species. The non-ectomycorrhizal fungi also had significantly different diversity and community composition between the canopy and terrestrial environments. Like the ectomycorrhizal community, some non-ectomycorrhizal taxa were significantly differentially represented in either the terrestrial or canopy environment. The canopy soil microhabitat provides a novel environment for growth of ectomycorrhizal adventitious roots and enables the spatial partitioning of ectomycorrhizal and non-ectomycorrhizal fungal diversity in the forest.
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Affiliation(s)
- Andy R. Nilsen
- Department of Botany, University of Otago, Dunedin, New Zealand
| | | | - Paul L. Guy
- Department of Botany, University of Otago, Dunedin, New Zealand
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