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Wieczorkowski JD, Lehmann CER, Archibald S, Banda S, Goyder DJ, Kaluwe M, Kapinga K, Larridon I, Mashau AC, Phiri E, Syampungani S. Fire facilitates ground layer plant diversity in a Miombo ecosystem. ANNALS OF BOTANY 2024; 133:743-756. [PMID: 38468311 PMCID: PMC11082521 DOI: 10.1093/aob/mcae035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 03/07/2024] [Indexed: 03/13/2024]
Abstract
BACKGROUND AND AIMS Little is known about the response of ground layer plant communities to fire in Miombo ecosystems, which is a global blind spot of ecological understanding. We aimed: (1) to assess the impact of three experimentally imposed fire treatments on ground layer species composition and compare it with patterns observed for trees; and (2) to analyse the effect of fire treatments on species richness to assess how responses differ among plant functional groups. METHODS At a 60-year-long fire experiment in Zambia, we quantified the richness and diversity of ground layer plants in terms of taxa and functional groups across three experimental fire treatments of late dry-season fire, early dry-season fire and fire exclusion. Data were collected in five repeat surveys from the onset of the wet season to the early dry season. KEY RESULTS Of the 140 ground layer species recorded across the three treatments, fire-maintained treatments contributed most of the richness and diversity, with the least number of unique species found in the no-fire treatment. The early-fire treatment was more similar in composition to the no-fire treatment than to the late-fire treatment. C4 grass and geoxyle richness were highest in the late-fire treatment, and there were no shared sedge species between the late-fire and other treatments. At a plot level, the average richness in the late-fire treatment was twice that of the fire exclusion treatment. CONCLUSIONS Heterogeneity in fire seasonality and intensity supports diversity of a unique flora by providing a diversity of local environments. African ecosystems face rapid expansion of land- and fire-management schemes for carbon offsetting and sequestration. We demonstrate that analyses of the impacts of such schemes predicated on the tree flora alone are highly likely to underestimate impacts on biodiversity. A research priority must be a new understanding of the Miombo ground layer flora integrated into policy and land management.
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Affiliation(s)
- Jakub D Wieczorkowski
- School of GeoSciences, The University of Edinburgh, Edinburgh EH8 9XP, UK
- Tropical Diversity, Royal Botanic Garden Edinburgh, Edinburgh EH3 5LR, UK
| | - Caroline E R Lehmann
- School of GeoSciences, The University of Edinburgh, Edinburgh EH8 9XP, UK
- Tropical Diversity, Royal Botanic Garden Edinburgh, Edinburgh EH3 5LR, UK
- Centre for African Ecology, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg 2050, South Africa
| | - Sally Archibald
- Centre for African Ecology, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg 2050, South Africa
| | - Sarah Banda
- Herbarium, Division of Forest Research, Forestry Department, PO Box 22099, Kitwe, Zambia
| | - David J Goyder
- Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AE, UK
| | - Mokwani Kaluwe
- Herbarium, Division of Forest Research, Forestry Department, PO Box 22099, Kitwe, Zambia
| | - Kondwani Kapinga
- Dag Hammarskjöld Institute for Peace and Conflict Studies – Environment, Sustainable Development and Peace, Copperbelt University, PO Box 21692, Kitwe, Zambia
| | | | - Aluoneswi C Mashau
- Centre for African Ecology, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg 2050, South Africa
- Foundational Research and Services, South African National Biodiversity Institute (SANBI), Private Bag X101, Pretoria 0184, South Africa
| | - Elina Phiri
- Herbarium, Division of Forest Research, Forestry Department, PO Box 22099, Kitwe, Zambia
| | - Stephen Syampungani
- Oliver R Tambo Africa Research Chair Initiative for Environment and Development, Copperbelt University, PO Box 21692, Kitwe, Zambia
- Department of Plant and Soil Sciences, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa
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2
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Clarke VC, Marcelo-Silva J, Claassens S, Siebert SJ. Crinum bulbispermum, a Medicinal Geophyte with Phytostabilization Properties in Metal-Enriched Mine Tailings. PLANTS (BASEL, SWITZERLAND) 2023; 13:79. [PMID: 38202387 PMCID: PMC10780652 DOI: 10.3390/plants13010079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 12/18/2023] [Accepted: 12/20/2023] [Indexed: 01/12/2024]
Abstract
Ancient grasslands are lost through transformation to agriculture, mining, and urban expansion. Land-use change leads to ecosystem degradation and a subsequent loss of biodiversity. Globally, degraded grasslands have become a priority for restoration efforts to recover lost ecosystem services. Although the ecological and social benefits of woody species and grasses are well documented, limited research has considered the use of forbs for restoration purposes despite their benefits (e.g., C sequestration and medicinal uses). The aim of this study was to determine if Crinum bulbispermum (Burm.f.) Milne-Redh. & Schweick., a medicinal geophyte, could form part of restoration initiatives to restore mine soils in grasslands of the South African Highveld. A pot experiment was conducted to assess the performance of C. bulbispermum in a random design, with three soil treatments varying in level of degradation and metal contamination. The plants were monitored for 12 months, and the morphological characters were measured monthly to assess performance and survival. Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the soil and plant tissue concentration of potentially toxic metals. The results indicated that mine tailings negatively affected the growth and development of C. bulbispermum. Although the survival rates indicated that it could survive on tailings, its below-par productivity indicated that the species is not ideal for restoration purposes unless the tailings are ameliorated with topsoil. Although there was root accumulation of metals (Co, Cd, Cu, Mo, and Zn), there was no translocation to the bulbs and leaves, which makes C. bulbispermum suitable for medicinal use even when grown on metal-enriched soil. This species may not be viable for phytoremediation but is a contender to be used in phytostabilization due to its ecological advantages and the fact that it does not accumulate or store metals. These findings underscore the importance of considering geophytes in grassland restoration strategies, expanding their ecological and societal benefits beyond conventional approaches.
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Affiliation(s)
- Vincent C. Clarke
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2531, South Africa; (V.C.C.); (S.C.)
| | - João Marcelo-Silva
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2531, South Africa; (V.C.C.); (S.C.)
| | - Sarina Claassens
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2531, South Africa; (V.C.C.); (S.C.)
- School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Stefan J. Siebert
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2531, South Africa; (V.C.C.); (S.C.)
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3
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Soil seed banks along a woody plant removal gradient in a semi-arid savanna of South Africa: Implications for restoration. ACTA OECOLOGICA 2023. [DOI: 10.1016/j.actao.2023.103891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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4
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Holdo RM, Nippert JB. Linking resource- and disturbance-based models to explain tree-grass coexistence in savannas. THE NEW PHYTOLOGIST 2023; 237:1966-1979. [PMID: 36451534 DOI: 10.1111/nph.18648] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 11/06/2022] [Indexed: 06/17/2023]
Abstract
Savannas cover a significant fraction of the Earth's land surface. In these ecosystems, C3 trees and C4 grasses coexist persistently, but the mechanisms explaining coexistence remain subject to debate. Different quantitative models have been proposed to explain coexistence, but these models make widely contrasting assumptions about which mechanisms are responsible for savanna persistence. Here, we show that no single existing model fully captures all key elements required to explain tree-grass coexistence across savanna rainfall gradients, but many models make important contributions. We show that recent empirical work allows us to combine many existing elements with new ideas to arrive at a synthesis that combines elements of two dominant frameworks: Walter's two-layer model and demographic bottlenecks. We propose that functional rooting separation is necessary for coexistence and is the crux of the coexistence problem. It is both well-supported empirically and necessary for tree persistence, given the comprehensive grass superiority for soil moisture acquisition. We argue that eventual tree dominance through shading is precluded by ecohydrological constraints in dry savannas and by fire and herbivores in wet savannas. Strong asymmetric grass-tree competition for soil moisture limits tree growth, exposing trees to persistent demographic bottlenecks.
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Affiliation(s)
- Ricardo M Holdo
- Odum School of Ecology, University of Georgia, Athens, GA, 30602, USA
| | - Jesse B Nippert
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
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5
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Botha D, du Plessis M, Siebert F, Barnard S. Introducing an rbcL and a trnL reference library to aid in the metabarcoding analysis of foraged plants from two semi-arid eastern South African savanna bioregions. PLoS One 2023; 18:e0286144. [PMID: 37205700 DOI: 10.1371/journal.pone.0286144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 05/10/2023] [Indexed: 05/21/2023] Open
Abstract
Success of a metabarcoding study is determined by the extent of taxonomic coverage and the quality of records available in the DNA barcode reference database used. This study aimed to create an rbcL and a trnL (UAA) DNA barcode sequence reference database of plant species that are potential herbivore foraging targets and commonly found in semi-arid savannas of eastern South Africa. An area-specific species list of 765 species was compiled according to plant collection records available and areas comparable to an eastern semi-arid South African savanna. Thereafter, rbcL and trnL sequences of species from this list were mined from GenBank and BOLD sequence databases according to specific quality criteria to ensure accurate taxonomic coverage and resolution. These were supplemented with sequences of 24 species sequenced for this study. A phylogenetic approach, employing Neighbor-Joining, was used to verify the topology of the reference libraries to known angiosperm phylogeny. The taxonomic reliability of these reference libraries was evaluated by testing for the presence of a barcode gap, identifying a data-appropriate identification threshold, and determining the identification accuracy of reference sequences via primary distance-based criteria. The final rbcL reference dataset consisted of 1238 sequences representing 318 genera and 562 species. The final trnL dataset consisted of 921 sequences representing 270 genera and 461 species. Barcode gaps were found for 76% of the taxa in the rbcL barcode reference dataset and 68% of the taxa in the trnL barcode reference dataset. The identification success rate, calculated with the k-nn criterion was 85.86% for the rbcL dataset and 73.72% for the trnL dataset. The datasets for rbcL and trnL combined during this study are not presented as complete DNA reference libraries, but rather as two datasets that should be used in unison to identify plants present in the semi-arid eastern savannas of South Africa.
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Affiliation(s)
- Danielle Botha
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
| | - Mornè du Plessis
- Core Sequencing Facility, National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, Johannesburg, South Africa
| | - Frances Siebert
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
| | - Sandra Barnard
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
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6
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Endress BA, Averett JP, Steinmetz S, Quaempts EJ. Forgotten forbs: Standard vegetation surveys underrepresent ecologically and culturally important forbs in a threatened grassland ecosystem. CONSERVATION SCIENCE AND PRACTICE 2022. [DOI: 10.1111/csp2.12813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Bryan A. Endress
- Eastern Oregon Agriculture Research Center‐Union Experiment Station, Department of Animal and Rangeland Sciences Oregon State University Corvallis Oregon USA
- Eastern Oregon Agriculture and Natural Resource Program Oregon State University Corvallis Oregon USA
| | - Joshua P. Averett
- Eastern Oregon Agriculture Research Center‐Union Experiment Station, Department of Animal and Rangeland Sciences Oregon State University Corvallis Oregon USA
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7
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Wieczorkowski JD, Lehmann CER. Encroachment diminishes herbaceous plant diversity in grassy ecosystems worldwide. GLOBAL CHANGE BIOLOGY 2022; 28:5532-5546. [PMID: 35815499 PMCID: PMC9544121 DOI: 10.1111/gcb.16300] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 04/24/2022] [Accepted: 05/29/2022] [Indexed: 05/17/2023]
Abstract
Woody encroachment is ubiquitous in grassy ecosystems worldwide, but its global impacts on the diversity of herbaceous plants that characterise and define these ecosystems remain unquantified. The pervasiveness of encroachment is relatively easily observed via remote sensing, but its impacts on plant diversity and richness below the canopy can only be observed via field-based studies. Via a meta-analysis of 42 field studies across tropical to temperate grassy ecosystems, we quantified how encroachment altered herbaceous species richness, and the richness of forbs, C3 graminoids and C4 graminoids. Across studies, the natural logarithm of the response ratio (lnRR) of herbaceous species richness ranged from -3.33 to 0.34 with 87% of encroached ecosystems negatively impacted. Assessment of the extent of encroachment, duration of encroachment, mean annual rainfall, latitude, and continent demonstrated that only extent of encroachment had relevance in the data (univariate model including a random effect of study explained 45.4% of variance). The global weighted mean lnRR of species richness decreased from -0.245 at <33% of woody cover increase, to -0.562 at 33%-66%, and to -0.962 at >66%. Continued encroachment results in substantial loss of herbaceous diversity at medium and high extents, with a loss of richness that is not replaced. Although all functional groups are significantly negatively impacted by encroachment, forb richness is relatively more sensitive than graminoid richness, and C4 graminoid richness relatively more than C3 graminoid richness. Although no geographic or climatic correlates had relevance in the data, encroachment as an emergent product of global change coalesces to decrease ground layer light availability, lead to loss of fire and grazers, and alter hydrology and soils. Encroachment is accelerating and grassy ecosystems require urgent attention to determine critical woody cover thresholds that facilitate diverse and resilient grassy ecosystems.
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Affiliation(s)
- Jakub D. Wieczorkowski
- School of GeoSciencesThe University of EdinburghEdinburghUK
- Tropical DiversityRoyal Botanic Garden EdinburghEdinburghUK
| | - Caroline E. R. Lehmann
- School of GeoSciencesThe University of EdinburghEdinburghUK
- Tropical DiversityRoyal Botanic Garden EdinburghEdinburghUK
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8
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Seymour CL, Joseph GS, Calitz W, Henschel JR, Ramaswiela T, van der Merwe H. Mean height increase in saplings of a keystone woody savanna species over 15 years similar to that over a single season. Ecosphere 2022. [DOI: 10.1002/ecs2.4173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Colleen L. Seymour
- South African National Biodiversity Institute Kirstenbosch Research Centre Claremont South Africa
- DST/NRF Centre of Excellence at the Percy FitzPatrick Institute of African Ornithology University of Cape Town Rondebosch South Africa
| | - Grant S. Joseph
- DST/NRF Centre of Excellence at the Percy FitzPatrick Institute of African Ornithology University of Cape Town Rondebosch South Africa
- SARChI‐Chair on Biodiversity Value and Change, Department of Zoology, School of Mathematical and Natural Science University of Venda Thohoyandou South Africa
| | - Wynand Calitz
- South African Environmental Observation Network (SAEON), Arid Lands Node Kimberley South Africa
| | - Joh R. Henschel
- South African Environmental Observation Network (SAEON), Arid Lands Node Kimberley South Africa
- Centre for Environmental Management University of the Free State Bloemfontein South Africa
| | - Tshililo Ramaswiela
- South African Environmental Observation Network (SAEON), Arid Lands Node Kimberley South Africa
| | - Helga van der Merwe
- South African Environmental Observation Network (SAEON), Arid Lands Node Kimberley South Africa
- Department of Biological Sciences University of Cape Town Cape Town South Africa
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9
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Wieczorkowski JD, Lehmann CER. Encroachment diminishes herbaceous plant diversity in grassy ecosystems worldwide. GLOBAL CHANGE BIOLOGY 2022; 28:5532-5546. [PMID: 35815499 DOI: 10.6084/m9.figshare.19982180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 04/24/2022] [Accepted: 05/29/2022] [Indexed: 05/28/2023]
Abstract
Woody encroachment is ubiquitous in grassy ecosystems worldwide, but its global impacts on the diversity of herbaceous plants that characterise and define these ecosystems remain unquantified. The pervasiveness of encroachment is relatively easily observed via remote sensing, but its impacts on plant diversity and richness below the canopy can only be observed via field-based studies. Via a meta-analysis of 42 field studies across tropical to temperate grassy ecosystems, we quantified how encroachment altered herbaceous species richness, and the richness of forbs, C3 graminoids and C4 graminoids. Across studies, the natural logarithm of the response ratio (lnRR) of herbaceous species richness ranged from -3.33 to 0.34 with 87% of encroached ecosystems negatively impacted. Assessment of the extent of encroachment, duration of encroachment, mean annual rainfall, latitude, and continent demonstrated that only extent of encroachment had relevance in the data (univariate model including a random effect of study explained 45.4% of variance). The global weighted mean lnRR of species richness decreased from -0.245 at <33% of woody cover increase, to -0.562 at 33%-66%, and to -0.962 at >66%. Continued encroachment results in substantial loss of herbaceous diversity at medium and high extents, with a loss of richness that is not replaced. Although all functional groups are significantly negatively impacted by encroachment, forb richness is relatively more sensitive than graminoid richness, and C4 graminoid richness relatively more than C3 graminoid richness. Although no geographic or climatic correlates had relevance in the data, encroachment as an emergent product of global change coalesces to decrease ground layer light availability, lead to loss of fire and grazers, and alter hydrology and soils. Encroachment is accelerating and grassy ecosystems require urgent attention to determine critical woody cover thresholds that facilitate diverse and resilient grassy ecosystems.
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Affiliation(s)
- Jakub D Wieczorkowski
- School of GeoSciences, The University of Edinburgh, Edinburgh, UK
- Tropical Diversity, Royal Botanic Garden Edinburgh, Edinburgh, UK
| | - Caroline E R Lehmann
- School of GeoSciences, The University of Edinburgh, Edinburgh, UK
- Tropical Diversity, Royal Botanic Garden Edinburgh, Edinburgh, UK
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10
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Averett JP, Endress BA. Forb composition gradients and intra‐annual variation in a threatened Pacific Northwest Bunchgrass Prairie. Ecol Evol 2022; 12:e9021. [PMID: 35784076 PMCID: PMC9217882 DOI: 10.1002/ece3.9021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 05/05/2022] [Accepted: 05/19/2022] [Indexed: 11/06/2022] Open
Affiliation(s)
- Joshua P. Averett
- Eastern Oregon Agricultural Research Center‐ Union Station Oregon State University Union Oregon USA
| | - Bryan A. Endress
- Eastern Oregon Agricultural Research Center‐ Union Station Oregon State University Union Oregon USA
- Eastern Oregon Agriculture and Natural Resource Program One University Blvd La Grande Oregon USA
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11
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Weber B, Belnap J, Büdel B, Antoninka AJ, Barger NN, Chaudhary VB, Darrouzet-Nardi A, Eldridge DJ, Faist AM, Ferrenberg S, Havrilla CA, Huber-Sannwald E, Malam Issa O, Maestre FT, Reed SC, Rodriguez-Caballero E, Tucker C, Young KE, Zhang Y, Zhao Y, Zhou X, Bowker MA. What is a biocrust? A refined, contemporary definition for a broadening research community. Biol Rev Camb Philos Soc 2022; 97:1768-1785. [PMID: 35584903 PMCID: PMC9545944 DOI: 10.1111/brv.12862] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 04/10/2022] [Accepted: 04/12/2022] [Indexed: 12/22/2022]
Abstract
Studies of biological soil crusts (biocrusts) have proliferated over the last few decades. The biocrust literature has broadened, with more studies assessing and describing the function of a variety of biocrust communities in a broad range of biomes and habitats and across a large spectrum of disciplines, and also by the incorporation of biocrusts into global perspectives and biogeochemical models. As the number of biocrust researchers increases, along with the scope of soil communities defined as ‘biocrust’, it is worth asking whether we all share a clear, universal, and fully articulated definition of what constitutes a biocrust. In this review, we synthesize the literature with the views of new and experienced biocrust researchers, to provide a refined and fully elaborated definition of biocrusts. In doing so, we illustrate the ecological relevance and ecosystem services provided by them. We demonstrate that biocrusts are defined by four distinct elements: physical structure, functional characteristics, habitat, and taxonomic composition. We describe outgroups, which have some, but not all, of the characteristics necessary to be fully consistent with our definition and thus would not be considered biocrusts. We also summarize the wide variety of different types of communities that fall under our definition of biocrusts, in the process of highlighting their global distribution. Finally, we suggest the universal use of the Belnap, Büdel & Lange definition, with minor modifications: Biological soil crusts (biocrusts) result from an intimate association between soil particles and differing proportions of photoautotrophic (e.g. cyanobacteria, algae, lichens, bryophytes) and heterotrophic (e.g. bacteria, fungi, archaea) organisms, which live within, or immediately on top of, the uppermost millimetres of soil. Soil particles are aggregated through the presence and activity of these often extremotolerant biota that desiccate regularly, and the resultant living crust covers the surface of the ground as a coherent layer. With this detailed definition of biocrusts, illustrating their ecological functions and widespread distribution, we hope to stimulate interest in biocrust research and inform various stakeholders (e.g. land managers, land users) on their overall importance to ecosystem and Earth system functioning.
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Affiliation(s)
- Bettina Weber
- Division of Plant Sciences, Institute for Biology, University of Graz, Holteigasse 6, 8010, Graz, Austria.,Multiphase Chemistry Department, Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128, Mainz, Germany
| | - Jayne Belnap
- Southwest Biological Science Center, U.S. Geological Survey, 2290 S. Resource Blvd, Moab, UT, 84532, USA
| | - Burkhard Büdel
- Biology Institute, University of Kaiserslautern, PO Box 3049, 67653, Kaiserslautern, Germany
| | - Anita J Antoninka
- School of Forestry, Northern Arizona University, 200 E. Pine Knoll Drive, Box 15018, Flagstaff, AZ, 86011, USA
| | - Nichole N Barger
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Campus Box 334, Boulder, CO, 80309, USA
| | - V Bala Chaudhary
- Department of Environmental Studies, Dartmouth College, 6182 Steele Hall, 39 College Street, Hanover, NH, 03755, USA
| | - Anthony Darrouzet-Nardi
- Department of Biological Sciences, University of Texas at El Paso, 500 W. University Ave, El Paso, TX, 79968, USA
| | - David J Eldridge
- Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Akasha M Faist
- Department of Animal and Range Sciences, New Mexico State University, PO Box 30003, MSC 3-I, Las Cruces, NM, 88003, USA
| | - Scott Ferrenberg
- Department of Biology, New Mexico State University, PO Box 30001, MSC 3AF, Las Cruces, NM, 88003, USA
| | - Caroline A Havrilla
- Department of Forest and Rangeland Stewardship, Colorado State University, 1472 Campus Delivery, Colorado State University, Fort Collins, CO, 80521, USA
| | - Elisabeth Huber-Sannwald
- Division of Environmental Sciences, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055, Col. 4ta Sección, CP 78216, San Luis Potosi, SLP, Mexico
| | - Oumarou Malam Issa
- Institute of Ecology and Environmental Sciences of Paris (IEES-Paris), SU/IRD/CNRS/INRAE/UPEC, 32, Avenue Henry Varagnat, F-93143, Bondy Cedex, France
| | - Fernando T Maestre
- Instituto Multidisciplinar para el Estudio del Medio "Ramón Margalef", Universidad de Alicante, Carretera de San Vicente del Raspeig s/n, 03690, San Vicente del Raspeig, Spain.,Departamento de Ecología, Universidad de Alicante, Carretera de San Vicente del Raspeig s/n, 03690, San Vicente del Raspeig, Spain
| | - Sasha C Reed
- Southwest Biological Science Center, U.S. Geological Survey, 2290 S. Resource Blvd, Moab, UT, 84532, USA
| | - Emilio Rodriguez-Caballero
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128, Mainz, Germany.,Department of Agronomy and Centro de Investigación de Colecciones Científicas (CECOUAL), Universidad de Almería, carretera Sacramento s/n, 04120, La cañada de San Urbano, Almeria, Spain
| | - Colin Tucker
- USDA Forest Service, Northern Research Station, 410 MacInnes Drive, Houghton, MI, 49931-1134, USA
| | - Kristina E Young
- Extension Agriculture and Natural Resources, Utah State University, 1850 S. Aggie Blvd, Moab, UT, 84532, USA
| | - Yuanming Zhang
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Bejing Road, Urumqi City, 830011, Xinjiang, China
| | - Yunge Zhao
- Institute of Soil and Water Conservation, Northwest A & F University, 26 Xinong Road, Yangling, Shaanxi, 712100, China
| | - Xiaobing Zhou
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 818 South Bejing Road, Urumqi City, 830011, Xinjiang, China
| | - Matthew A Bowker
- School of Forestry, Northern Arizona University, 200 E. Pine Knoll Drive, Box 15018, Flagstaff, AZ, 86011, USA
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12
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Large herbivores suppress liana infestation in an African savanna. Proc Natl Acad Sci U S A 2021; 118:2101676118. [PMID: 34580170 DOI: 10.1073/pnas.2101676118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2021] [Indexed: 11/18/2022] Open
Abstract
African savannas are the last stronghold of diverse large-mammal communities, and a major focus of savanna ecology is to understand how these animals affect the relative abundance of trees and grasses. However, savannas support diverse plant life-forms, and human-induced changes in large-herbivore assemblages-declining wildlife populations and their displacement by livestock-may cause unexpected shifts in plant community composition. We investigated how herbivory affects the prevalence of lianas (woody vines) and their impact on trees in an East African savanna. Although scarce (<2% of tree canopy area) and defended by toxic latex, the dominant liana, Cynanchum viminale (Apocynaceae), was eaten by 15 wild large-herbivore species and was consumed in bulk by native browsers during experimental cafeteria trials. In contrast, domesticated ungulates rarely ate lianas. When we experimentally excluded all large herbivores for periods of 8 to 17 y (simulating extirpation), liana abundance increased dramatically, with up to 75% of trees infested. Piecewise exclusion of different-sized herbivores revealed functional complementarity among size classes in suppressing lianas. Liana infestation reduced tree growth and reproduction, but herbivores quickly cleared lianas from trees after the removal of 18-y-old exclosure fences (simulating rewilding). A simple model of liana contagion showed that, without herbivores, the long-term equilibrium could be either endemic (liana-tree coexistence) or an all-liana alternative stable state. We conclude that ongoing declines of wild large-herbivore populations will disrupt the structure and functioning of many African savannas in ways that have received little attention and that may not be mitigated by replacing wildlife with livestock.
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Zhou T, Sun J, Zong N, Hou G, Shi P. Community species diversity mediates the trade-off between aboveground and belowground biomass for grasses and forbs in degraded alpine meadow, Tibetan Plateau. Ecol Evol 2021; 11:13259-13267. [PMID: 34646467 PMCID: PMC8495812 DOI: 10.1002/ece3.8048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 08/03/2021] [Accepted: 08/06/2021] [Indexed: 11/11/2022] Open
Abstract
Although many empirical experiments have shown that increasing degradation results in lower aboveground biomass (AGB), our knowledge of the magnitude of belowground biomass (BGB) for individual plants is a prerequisite for accurately revealing the biomass trade-off in degraded grasslands. Here, by linking the AGB and BGB of individual plants, species in the community, and soil properties, we explored the biomass partitioning patterns in different plant functional groups (grasses of Stipa capillacea and forbs of Anaphalis xylorhiza). Our results indicated that 81% and 60% of the biomass trade-off variations could be explained by environmental factors affecting grasses and forbs, respectively. The change in community species diversity dominated the biomass trade-off via either direct or indirect effects on soil properties and biomass. However, the community species diversity imparted divergent effects on the biomass trade-off for grasses (scored at -0.72) and forbs (scored at 0.59). Our findings suggest that plant communities have evolved two contrasting strategies of biomass allocation patterns in degraded grasslands. These are the "conservative" strategy in grasses, in which plants with larger BGB trade-off depends on gigantic roots for soil resources, and the "opportunistic" strategy in forbs, in which plants can adapt to degraded lands using high variation and optimal biomass allocation.
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Affiliation(s)
- Tiancai Zhou
- Key Laboratory of Ecosystem Network Observation and Modelling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China
- College of Resources and Environment University of Chinese Academy of Sciences Beijing China
| | - Jian Sun
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE) Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing China
| | - Ning Zong
- Key Laboratory of Ecosystem Network Observation and Modelling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China
| | - Ge Hou
- Key Laboratory of Ecosystem Network Observation and Modelling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China
- College of Resources and Environment University of Chinese Academy of Sciences Beijing China
| | - Peili Shi
- Key Laboratory of Ecosystem Network Observation and Modelling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China
- College of Resources and Environment University of Chinese Academy of Sciences Beijing China
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Wagner TC, Uiseb K, Fischer C. Rolling pits of Hartmann's mountain zebra ( Zebra equus hartmannae) increase vegetation diversity and landscape heterogeneity in the Pre-Namib. Ecol Evol 2021; 11:13036-13051. [PMID: 34646451 PMCID: PMC8495834 DOI: 10.1002/ece3.7983] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 07/17/2021] [Accepted: 07/20/2021] [Indexed: 11/07/2022] Open
Abstract
Microsites created by soil-disturbing animals are important landscape elements in arid environments. In the Pre-Namib, dust-bathing behavior of the near-endemic Hartmann's mountain zebra creates unique rolling pits that persist in the landscape. However, the ecohydrological characteristics and the effects of those microsites on the vegetation and on organisms of higher trophic levels are still unknown. In our study, we characterized the soil grain size composition and infiltration properties of rolling pits and reference sites and recorded vegetation and arthropod assemblages during the rainy season of five consecutive years with different amounts of seasonal rainfall. We further used the excess green vegetation index derived from drone imagery to demonstrate the different green up and wilting of pits and references after a rainfall event. In contrast to the surrounding grassland, rolling pits had finer soil with higher nutrient content, collected runoff, showed a higher infiltration, and kept soil moisture longer. Vegetation in the rolling pits was denser, dominated by annual forbs and remained green for longer periods. The denser vegetation resulted in a slightly higher activity density of herbivorous arthropods, which in turn increased the activity density of omnivorous and predatory arthropods. In times of drought, the rolling pits could act as safe sites and refuges for forbs and arthropods. With their rolling pits, Hartmann's mountain zebras act as ecosystem engineers, contributing to the diversity of forb communities and heterogeneity of the landscape in the Pre-Namib.
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Affiliation(s)
- Thomas C. Wagner
- Restoration EcologySchool of Life SciencesTechnische Universität MünchenFreisingGermany
| | - Kenneth Uiseb
- Directorate of Scientific ServicesNamibia Ministry of Environment, Forestry and TourismWindhoekNamibia
| | - Christina Fischer
- Restoration EcologySchool of Life SciencesTechnische Universität MünchenFreisingGermany
- Faunistics and Wildlife ConservationDepartment of Agriculture, Ecotrophology, and Landscape DevelopmentAnhalt University of Applied SciencesBernburgGermany
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Research Progression of the Genus Merremia: A Comprehensive Review on the Nutritional Value, Ethnomedicinal Uses, Phytochemistry, Pharmacology, and Toxicity. PLANTS 2021; 10:plants10102070. [PMID: 34685875 PMCID: PMC8537340 DOI: 10.3390/plants10102070] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/23/2021] [Accepted: 09/24/2021] [Indexed: 12/22/2022]
Abstract
The genus Merremia Dennst. ex Endl. (Convolvulaceae) is a rich source of structurally diverse phytochemicals with therapeutic relevance. This review presents the first comprehensive, up-to-date information and research progression on the nutritional value, ethnomedicinal uses, phytochemistry, pharmacological activities, and toxicity of the genus Merremia. Using the key search term “Merremia”, relevant documents and information were retrieved from electronic databases. Relevant documents were uploaded in RStudio with installed bibliometric software packages and used for data retrieval, tabulation, and network visualization. Bibliometric analysis revealed that ca. 55% of the studies related to Merremia were published in the last decade, which can be grouped into four thematic areas: (i) drug formulation, (ii) taxonomy, (iii) chemical analysis, and (iv) treatment of diseases. Ethnomedicinal uses, phytochemistry, and biological activities studies showed that species in the genus are promising medicinal plants with various pharmaceutical potentials. However, clinical studies to validate the efficacy of the reported bioactivities and the mechanisms underlying the various activities are lacking and should constitute a future research focus. Additionally, reports on the nutritional and antinutritional constituents of Merremia species revealed that the species meet high nutritional quality criteria for animals and are therefore suitable for inclusion in livestock diets. The few available investigations on toxicity indicated that most Merremia species are safe for human and animal use but not with prolonged chronic administration.
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Wana D, Smith SW, Coleman KER, Speed JDM. Proximity to high densities of pastoral settlements reduces grassland regrowth in a protected tropical savanna. Biotropica 2021. [DOI: 10.1111/btp.12977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Desalegn Wana
- Department of Geography & Environmental Studies Addis Ababa University Addis Ababa Ethiopia
| | - Stuart W. Smith
- Department of Biology Norwegian University of Science and Technology Trondheim Norway
- Asian School of Environment Nanyang Technological University Singapore City Singapore
| | | | - James D. M. Speed
- NTNU University Museum Norwegian University of Science and Technology Trondheim Norway
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Makhado RA, Curlewis BJ, Luus‐Powell WJ, Potgieter MJ. Forbs and herbs diet of the
Tragelaphus strepsiceros
at Musina Nature Reserve, Limpopo Province, South Africa. Afr J Ecol 2020. [DOI: 10.1111/aje.12791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Basil J. Curlewis
- Department of Biodiversity University of Limpopo Sovenga South Africa
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Silveira FAO, Arruda AJ, Bond W, Durigan G, Fidelis A, Kirkman K, Oliveira RS, Overbeck GE, Sansevero JBB, Siebert F, Siebert SJ, Young TP, Buisson E. Myth‐busting tropical grassy biome restoration. Restor Ecol 2020. [DOI: 10.1111/rec.13202] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Fernando A. O. Silveira
- Departamento de Genética, Ecologia e Evolução Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais Av. Antônio Carlos 6627, CEP 31270‐901 Belo Horizonte MG Brazil
| | - André J. Arruda
- Departamento de Genética, Ecologia e Evolução Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais Av. Antônio Carlos 6627, CEP 31270‐901 Belo Horizonte MG Brazil
- School of Biological Sciences University of Western Australia Perth Western Australia Australia
| | - William Bond
- Department of Biological Sciences University of Cape Town Rondebosch South Africa
| | - Giselda Durigan
- Floresta Estadual de Assis Instituto Florestal do Estado de São Paulo P.O. Box 104, 19802‐970 Assis SP Brazil
| | - Alessandra Fidelis
- Lab of Vegetation Ecology, Instituto de Biociências Universidade Estadual Paulista (UNESP) Av. 24A, 1515, 13506‐900 Rio Claro SP Brazil
| | - Kevin Kirkman
- Centre for Functional Biodiversity, School of Life Sciences University of KwaZulu‐Natal Durban South Africa
| | - Rafael S. Oliveira
- Department of Plant Biology, Institute of Biology University of Campinas—UNICAMP Campinas SP Brazil
| | - Gerhard E. Overbeck
- Departamento de Botânica Universidade Federal do Rio Grande do Sul Av. Bento Gonçalves 9500, CEP 91501‐970 Porto Alegre RS Brazil
| | - Jerônimo B. B Sansevero
- Departamento de Ciências Ambientais (DCA), Instituto de Florestas (IF) Universidade Federal Rural do Rio de Janeiro—UFRRJ BR 465, Km 07, CEP 23890‐000 Seropédica RJ Brazil
| | - Frances Siebert
- Unit for Environmental Sciences and Management North‐West University Potchefstroom 2520 South Africa
| | - Stefan J. Siebert
- Unit for Environmental Sciences and Management North‐West University Potchefstroom 2520 South Africa
| | - Truman P. Young
- Department of Plant Sciences University of California Davis CA 95616 U.S.A
| | - Elise Buisson
- Department of Plant Sciences University of California Davis CA 95616 U.S.A
- Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), Avignon Université, UMR CNRS IRD Aix Marseille Université, IUT Site Agroparc BP 61207, 84911 Avignon Cedex 09 France
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Six-year removal of co-dominant grasses alleviated competitive pressure on subdominant grasses but dominant shrub removal had neutral effects in a subalpine ecosystem. Glob Ecol Conserv 2020. [DOI: 10.1016/j.gecco.2020.e01167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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20
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Quantifying Long-Term Urban Grassland Dynamics: Biotic Homogenization and Extinction Debts. SUSTAINABILITY 2020. [DOI: 10.3390/su12051989] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Sustainable urban nature conservation calls for a rethinking of conventional approaches. Traditionally, conservationists have not incorporated the history of the landscape in management strategies. This study shows that extant vegetation patterns are correlated to past landscapes indicating potential extinction debts. We calculated urban landscape measures for seven time periods (1938–2019) and correlated it to three vegetation sampling events (1995, 2012, 2019) using GLM models. We also tested whether urban vegetation was homogenizing. Our results indicated that urban vegetation in our study area is not currently homogenizing but that indigenous forb species richness is declining significantly. Furthermore, long-term studies are essential as the time lags identified for different vegetation sampling periods changed as well as the drivers best predicting these changes. Understanding these dynamics are critical to ensuring sustainable conservation of urban vegetation for future citizens.
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21
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Malindie S, Buschke F, Codron D. Carbon isotope differences between grassland and savanna herbivores reveal environmentally driven rather than phylogenetically conserved niches. J Zool (1987) 2020. [DOI: 10.1111/jzo.12762] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- S. Malindie
- Centre for Environmental Management (IB 67) University of Free State Bloemfontein South Africa
| | - F.T. Buschke
- Centre for Environmental Management (IB 67) University of Free State Bloemfontein South Africa
| | - D. Codron
- Department of Zoology and Entomology (IB 49) University of Free State Bloemfontein South Africa
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