1
|
Bartholomew DC, Hayward R, Burslem DFRP, Bittencourt PRL, Chapman D, Bin Suis MAF, Nilus R, O'Brien MJ, Reynolds G, Rowland L, Banin LF, Dent D. Bornean tropical forests recovering from logging at risk of regeneration failure. Glob Chang Biol 2024; 30:e17209. [PMID: 38469989 DOI: 10.1111/gcb.17209] [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] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 01/08/2024] [Accepted: 01/17/2024] [Indexed: 03/13/2024]
Abstract
Active restoration through silvicultural treatments (enrichment planting, cutting climbers and liberation thinning) is considered an important intervention in logged forests. However, its ability to enhance regeneration is key for long-term recovery of logged forests, which remains poorly understood, particularly for the production and survival of seedlings in subsequent generations. To understand the long-term impacts of logging and restoration we tracked the diversity, survival and traits of seedlings that germinated immediately after a mast fruiting in North Borneo in unlogged and logged forests 30-35 years after logging. We monitored 5119 seedlings from germination for ~1.5 years across a mixed landscape of unlogged forests (ULs), naturally regenerating logged forests (NR) and actively restored logged forests via rehabilitative silvicultural treatments (AR), 15-27 years after restoration. We measured 14 leaf, root and biomass allocation traits on 399 seedlings from 15 species. Soon after fruiting, UL and AR forests had higher seedling densities than NR forest, but survival was the lowest in AR forests in the first 6 months. Community composition differed among forest types; AR and NR forests had lower species richness and lower evenness than UL forests by 5-6 months post-mast but did not differ between them. Differences in community composition altered community-weighted mean trait values across forest types, with higher root biomass allocation in NR relative to UL forest. Traits influenced mortality ~3 months post-mast, with more acquisitive traits and relative aboveground investment favoured in AR forests relative to UL forests. Our findings of reduced seedling survival and diversity suggest long time lags in post-logging recruitment, particularly for some taxa. Active restoration of logged forests recovers initial seedling production, but elevated mortality in AR forests lowers the efficacy of active restoration to enhance recruitment or diversity of seedling communities. This suggests current active restoration practices may fail to overcome barriers to regeneration in logged forests, which may drive long-term changes in future forest plant communities.
Collapse
Affiliation(s)
- David C Bartholomew
- School of Geography, University of Exeter, Exeter, UK
- Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
- Botanic Gardens Conservation International, Richmond, UK
| | - Robin Hayward
- Biological and Environmental Sciences, University of Stirling, Stirling, UK
- School of Earth and Environment, University of Leeds, Leeds, UK
| | | | | | - Daniel Chapman
- Biological and Environmental Sciences, University of Stirling, Stirling, UK
| | | | - Reuben Nilus
- Forest Research Centre Sepilok, Sandakan, Malaysia
| | - Michael J O'Brien
- Estación Experimental de Zonas Áridas, Consejo Superior de Investigaciones Científicas, Almería, Spain
| | - Glen Reynolds
- SE Asia Rainforest Research Partnership, Kota Kinabalu, Sabah, Malaysia
| | - Lucy Rowland
- School of Geography, University of Exeter, Exeter, UK
| | | | - Daisy Dent
- Smithsonian Tropical Research Institute, Balboa, Panama
- Department of Environmental Systems Science, ETH, Zürich, Switzerland
| |
Collapse
|
2
|
Guilbeault-Mayers X, Turner BL, Laliberté E. Greater root phosphatase activity of tropical trees at low phosphorus despite strong variation among species. Ecology 2020; 101:e03090. [PMID: 32329055 DOI: 10.1002/ecy.3090] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 01/30/2020] [Accepted: 04/01/2020] [Indexed: 11/07/2022]
Abstract
Soil phosphorus (P) availability in lowland tropical rainforests influences the distribution and growth of tropical tree species. Determining the P-acquisition strategies of tropical tree species could therefore yield insight into patterns of tree β-diversity across edaphic gradients. In particular, the synthesis of root phosphatases is likely to be of significance given that organic P represents a large pool of potentially available P in tropical forest soils. It has also been suggested that a high root phosphatase activity in putative nitrogen (N) -fixing legumes might explain their high abundance in lowland neotropical forests under low P supply. Here, we measured phosphomonoesterase (PME) activity on the first three root orders of co-occurring tropical tree species differing in their N-fixation capacity, growing on soils of contrasting P availability in Panama. Our results show that root PME activity was higher on average in P-poor than in P-rich soils, but that local variation in PME activity among co-occurring species within a site was larger than that explained by differences in soil P across sites. Legumes expressed higher PME activity than nonlegumes, but nodulated legumes (i.e., actively fixing nitrogen) did not differ from legumes without nodules, indicating that PME activity is unrelated to N fixation. Finally, PME activity declined with increasing root order, but the magnitude of the decline varied markedly among species, highlighting the importance of classifying fine roots into functional groups prior to measuring root traits. Our results support the hypothesis that low-P promotes a high root PME activity, although the high local variation in this trait among co-occurring species points toward a high functional diversity in P-acquisition strategies within an individual community.
Collapse
Affiliation(s)
- Xavier Guilbeault-Mayers
- Département de sciences biologiques, Institut de recherche en biologie végétale, Université de Montréal, 4101 Sherbrooke Est, Montréal, Quebec, H1X 2B1, Canada
| | - Benjamin L Turner
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Panama
| | - Etienne Laliberté
- Département de sciences biologiques, Institut de recherche en biologie végétale, Université de Montréal, 4101 Sherbrooke Est, Montréal, Quebec, H1X 2B1, Canada
| |
Collapse
|
3
|
Zalamea PC, Dalling JW, Sarmiento C, Arnold AE, Delevich C, Berhow MA, Ndobegang A, Gripenberg S, Davis AS. Dormancy-defense syndromes and tradeoffs between physical and chemical defenses in seeds of pioneer species. Ecology 2018; 99:1988-1998. [PMID: 30074614 DOI: 10.1002/ecy.2419] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 03/28/2018] [Accepted: 05/14/2018] [Indexed: 11/09/2022]
Abstract
Seeds of tropical pioneer trees have chemical and physical characteristics that determine their capacity to persist in the soil seed bank. These traits allow seeds to survive in the soil despite diverse predators and pathogens, and to germinate and recruit even decades after dispersal. Defenses in seedlings and adult plants often are described in terms of tradeoffs between chemical and physical defense, but the interplay of defensive strategies has been evaluated only rarely for seeds. Here we evaluated whether classes of seed defenses were negatively correlated across species (consistent with tradeoffs in defense strategies), or whether groups of traits formed associations across species (consistent with seed defense syndromes). Using 16 of the most common pioneer tree species in a neotropical lowland forest in Panama we investigated relationships among four physical traits (seed fracture resistance, seed coat thickness, seed permeability, and seed mass) and two chemical traits (number of phenolic compounds and phenolic peak area), and their association with seed persistence. In addition, seed toxicity was assessed with bioassays in which we evaluated the activity of seed extracts against representative fungal pathogens and a model invertebrate. We did not find univariate tradeoffs between chemical and physical defenses. Instead, we found that seed permeability - a trait that distinguishes physical dormancy from other dormancy types - was positively associated with chemical defense traits and negatively associated with physical defense traits. Using a linear discriminant analysis and a hierarchical cluster analysis we found evidence to distinguish three distinct seed defense syndromes that correspond directly with seed dormancy classes (i.e., quiescent, physical, and physiological). Our data suggest that short and long-term persistence of seeds can be achieved via two strategies: having permeable seeds that are well defended chemically, corresponding to the physiologically dormant defense syndrome; or having impermeable seeds that are well defended physically, corresponding to the physically dormant defense syndrome. In turn, transient seeds appear to have a lower degree of chemical and physical defenses, corresponding to the quiescent defense syndrome. Overall, we find that seed defense and seed dormancy are linked, suggesting that environmental pressures on seed persistence and for delayed germination can select for trait combinations defining distinct dormancy-defense syndromes.
Collapse
Affiliation(s)
| | - James W Dalling
- Smithsonian Tropical Research Institute, Apartado 0843, Balboa, Panama.,Department of Plant Biology, University of Illinois, Urbana, Illinois, 61801, USA
| | | | - A Elizabeth Arnold
- School of Plant Sciences, The University of Arizona, Tucson, Arizona, 85721, USA.,Department of Ecology and Evolutionary Biology, The University of Arizona, Tucson, Arizona, 85721, USA
| | - Carolyn Delevich
- Smithsonian Tropical Research Institute, Apartado 0843, Balboa, Panama
| | - Mark A Berhow
- National Center of Agricultural Utilization Research, United States Department of Agriculture - Agricultural Research Service, Peoria, Illinois, 61604, USA
| | - Anyangatia Ndobegang
- School of Plant Sciences, The University of Arizona, Tucson, Arizona, 85721, USA
| | - Sofia Gripenberg
- Department of Zoology, University of Oxford, Oxford, OX1 3SZ, UK
| | - Adam S Davis
- Global Change and Photosynthesis Research Unit, United States Department of Agriculture - Agricultural Research Service, Urbana, Illinois, 61801, USA
| |
Collapse
|