In mangroves of South Florida, plant debris accumulates and humifies to form peat. The structure and composition of mangrove peat differs among mangal sub-habitats, leading to categorically distinct peat types reflective of the taphonomically active zone (TAZ). Here, taphonomic processes degrade and shape the peat until it is sequestered in the depth of final burial (DFB). Sequestered peats provide historical archives of the mangal depositional environment and the palaeoecological context of peat formation that are used to reconstruct mangal sub-habitats. However, as peat passes through the TAZ, information about the precursor mangal sub-habitat is reduced, which may skew mangrove community reconstructions. To better understand the influence of the TAZ on peat formation, we analyzed plant organ- and taxon-based measures by characterizing surficial mangrove peats from two contrasting mangal sub-habitats in Barnes Sound, Florida: a tidally influenced, Rhizophora-dominated fringe sub-habitat; and an inundated, interior mixed forest basin sub-habitat. We found (1) peats formed in basin sites have greater amounts of leaf litter, which correlates with reduced tidal activity and restricted detritivore access to the litter layer; (2) peats formed in fringe sites have higher root percentages, or root–shoot ratios, which provide a reliable method to differentiate between peats at depth, and (3) mangal sub-habitats differ in preserved organismal signals, such as foraminifera and insect parts. Further, we compare our surficial core samples to historical, deep core samples from other South Florida mangrove peat deposits to establish modern peat analogs needed to decipher preserved mangrove peats. These comparisons suggest that few aerial plant organs survive the TAZ and sequestered peats are biased towards root-rich peats characteristic of fringe sub-habitats; however, sequestered peats with lower root-shoot ratios indicate leaf litter-rich peats formed in basin sub-habitats.
{"title":"Establishing Modern Peat Analogs to Decipher Mangal Sub-Habitats From Historical Peats","authors":"Samuel H. Neely, A. Raymond","doi":"10.58782/flmnh.wyms3450","DOIUrl":"https://doi.org/10.58782/flmnh.wyms3450","url":null,"abstract":"In mangroves of South Florida, plant debris accumulates and humifies to form peat. The structure and composition of mangrove peat differs among mangal sub-habitats, leading to categorically distinct peat types reflective of the taphonomically active zone (TAZ). Here, taphonomic processes degrade and shape the peat until it is sequestered in the depth of final burial (DFB). Sequestered peats provide historical archives of the mangal depositional environment and the palaeoecological context of peat formation that are used to reconstruct mangal sub-habitats. However, as peat passes through the TAZ, information about the precursor mangal sub-habitat is reduced, which may skew mangrove community reconstructions. To better understand the influence of the TAZ on peat formation, we analyzed plant organ- and taxon-based measures by characterizing surficial mangrove peats from two contrasting mangal sub-habitats in Barnes Sound, Florida: a tidally influenced, Rhizophora-dominated fringe sub-habitat; and an inundated, interior mixed forest basin sub-habitat. We found (1) peats formed in basin sites have greater amounts of leaf litter, which correlates with reduced tidal activity and restricted detritivore access to the litter layer; (2) peats formed in fringe sites have higher root percentages, or root–shoot ratios, which provide a reliable method to differentiate between peats at depth, and (3) mangal sub-habitats differ in preserved organismal signals, such as foraminifera and insect parts. Further, we compare our surficial core samples to historical, deep core samples from other South Florida mangrove peat deposits to establish modern peat analogs needed to decipher preserved mangrove peats. These comparisons suggest that few aerial plant organs survive the TAZ and sequestered peats are biased towards root-rich peats characteristic of fringe sub-habitats; however, sequestered peats with lower root-shoot ratios indicate leaf litter-rich peats formed in basin sub-habitats.","PeriodicalId":106523,"journal":{"name":"Bulletin of the Florida Museum of Natural History","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128436154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Species-environment interactions are integral to survivorship, especially when those environments test the extremes of organismal physiology. Large-bodied (>50kg) mammals, specifically artiodactyls and feliform carnivores, possess a specialized physiology known as carotid-rete-mediated selective brain cooling (CR-SBC), which has been established to be selectively advantageous in environments where water availability is limited and risk for dehydration is high. In this study, we investigate whether CR-SBC provides a release from physiological constraint imposed by the environment, specifically aridity. Using 18O values from tooth enamel as a proxy for water metabolism, we model the range in variance across 1265 individuals from species that possess a carotid rete against those without from three different environmental categories – arid, dry subhumid, and humid – using a non-parametric ANOVA. The results of the analysis indicate there is a comparatively higher, and statistically significant, amount of variance of 18O in mammals possessing CR-SBC than those without, especially within arid climates, that begins to equalize as environmental water availability increases. As environments become increasingly arid, understanding which species are more vulnerable to shifts in climate becomes more pertinent. The presence of CR-SBC provides a clear, binary feature by which to measure the relationship between the environment and species survivorship under varying levels of water availability, and is useful in informing and improving conservation tools, such as physiological distribution models.
{"title":"Variance of Carotid-Rete-Mediated Selective Brain Cooling Across Aridity Indices","authors":"Katherine Slenker, H. O'Brien, Lindsey T. Yann","doi":"10.58782/flmnh.hhfe1916","DOIUrl":"https://doi.org/10.58782/flmnh.hhfe1916","url":null,"abstract":"Species-environment interactions are integral to survivorship, especially when those environments test the extremes of organismal physiology. Large-bodied (>50kg) mammals, specifically artiodactyls and feliform carnivores, possess a specialized physiology known as carotid-rete-mediated selective brain cooling (CR-SBC), which has been established to be selectively advantageous in environments where water availability is limited and risk for dehydration is high. In this study, we investigate whether CR-SBC provides a release from physiological constraint imposed by the environment, specifically aridity. Using 18O values from tooth enamel as a proxy for water metabolism, we model the range in variance across 1265 individuals from species that possess a carotid rete against those without from three different environmental categories – arid, dry subhumid, and humid – using a non-parametric ANOVA. The results of the analysis indicate there is a comparatively higher, and statistically significant, amount of variance of 18O in mammals possessing CR-SBC than those without, especially within arid climates, that begins to equalize as environmental water availability increases. As environments become increasingly arid, understanding which species are more vulnerable to shifts in climate becomes more pertinent. The presence of CR-SBC provides a clear, binary feature by which to measure the relationship between the environment and species survivorship under varying levels of water availability, and is useful in informing and improving conservation tools, such as physiological distribution models.","PeriodicalId":106523,"journal":{"name":"Bulletin of the Florida Museum of Natural History","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128629619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Corentin Gibert, G. Escarguel, A. Vilmi, Jianjun Wang, Jenny L. McGuire
How biological communities are assembled is an old but lively debate, especially today, as the efficiency of conservation policies depend on our capacity to correctly identify the assembly processes at play within the species assemblages we aim to protect. The wide range of assembly modes, once seen as mutually exclusive hypothesis are now seen as part of a continuum where the opposite ends correspond to niche- and dispersal-assembly perspectives. Niche-assembled communities are closed and balanced with a stable taxonomic composition depending on deterministic processes when dispersal-assembled communities are open, in non-equilibrium state with constantly changing compositions depending on historical process and continuous dispersion between communities. The former must be protected by increasing habitat diversity and heterogeneity when the latter needing high connectivity to ensure dispersal between habitats. Protecting modern at-risk communities will require an understanding of how assembly processes have been affected by past climate change (both recent and ancient) or by the historical exploitation of ecosystems by humans. However, few methods exist that are capable of identifying assembly processes within paleontological datasets and producing time series at multiple scales due to missing information in the vast majority of the fossil record (e.g., abundance, environmental information, highly-resolved phylogeny) or due to limited precision of compatible methods (i.e. random vs. non-random patterns). The new PER-SIMPER method (and its associated DNCImper R package) can be used to identify and quantify the respective roles of niche and dispersal processes from the distribution of occurrences of extinct and extant species. Based on three modes of permutation of the occurrence matrix, I will illustrate PER-SIMPER with deep-time (e.g., trilobites), ancient (e.g. Cenozoic mammals) and modern datasets (e.g. small mountain mammals, host-flea assemblages).
{"title":"Per-Simper, An Innovative Method for Identifying Community Assembly Processes Within Modern, Recent, and Deep-Time Paleontological Assemblages","authors":"Corentin Gibert, G. Escarguel, A. Vilmi, Jianjun Wang, Jenny L. McGuire","doi":"10.58782/flmnh.dsol7912","DOIUrl":"https://doi.org/10.58782/flmnh.dsol7912","url":null,"abstract":"How biological communities are assembled is an old but lively debate, especially today, as the efficiency of conservation policies depend on our capacity to correctly identify the assembly processes at play within the species assemblages we aim to protect. The wide range of assembly modes, once seen as mutually exclusive hypothesis are now seen as part of a continuum where the opposite ends correspond to niche- and dispersal-assembly perspectives. Niche-assembled communities are closed and balanced with a stable taxonomic composition depending on deterministic processes when dispersal-assembled communities are open, in non-equilibrium state with constantly changing compositions depending on historical process and continuous dispersion between communities. The former must be protected by increasing habitat diversity and heterogeneity when the latter needing high connectivity to ensure dispersal between habitats. Protecting modern at-risk communities will require an understanding of how assembly processes have been affected by past climate change (both recent and ancient) or by the historical exploitation of ecosystems by humans. However, few methods exist that are capable of identifying assembly processes within paleontological datasets and producing time series at multiple scales due to missing information in the vast majority of the fossil record (e.g., abundance, environmental information, highly-resolved phylogeny) or due to limited precision of compatible methods (i.e. random vs. non-random patterns). The new PER-SIMPER method (and its associated DNCImper R package) can be used to identify and quantify the respective roles of niche and dispersal processes from the distribution of occurrences of extinct and extant species. Based on three modes of permutation of the occurrence matrix, I will illustrate PER-SIMPER with deep-time (e.g., trilobites), ancient (e.g. Cenozoic mammals) and modern datasets (e.g. small mountain mammals, host-flea assemblages).","PeriodicalId":106523,"journal":{"name":"Bulletin of the Florida Museum of Natural History","volume":"258 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134380515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sara H. Williams, Sabrina Shirazi, K. Hughes, Chris Abin, L. Welch, A. Mychajliw, Courtney A. Hofman
The mink (Neogale sp.) has been important species in North American ecosystems and communities for millennia; before European colonization, Indigenous families hunted and trapped mink for their pelts. As part of the euro-colonial fur trade (~1600-1900), wide-spread and intense harvest of mink and other furbearers transformed ecosystems, including the likely extinction of the sea mink (Neogale macrodon) in the Gulf of Maine. The American mink (Neogale vison) has slowly moved into areas that were previously inhabited by the sea mink in coastal and island Maine. The expansion of American mink has been implicated as a potential cause for the declining seabird populations on Maine islands. Here, we use metabarcoding of American mink scat collected in the USFWS Maine Coastal Islands National Wildlife Refuge to evaluate if American mink are predating upon seabirds. Preliminary analysis of mink scat from Petit Manan Island has not implicated mink in bird predation but we did recover host DNA and dietary components including lobster and fish (Cunner). Currently, managers remove American mink from the Refuge islands to protect nesting seabirds but perhaps the seabird populations are returning to population sizes of when sea mink was present in the area. Harvest of furbearers as part of the euro-colonial fur trade may still have implications for ecosystem form and function today.
{"title":"Metabarcoding of American Mink Scat to Explore Shifting Baselines in the Gulf of Maine","authors":"Sara H. Williams, Sabrina Shirazi, K. Hughes, Chris Abin, L. Welch, A. Mychajliw, Courtney A. Hofman","doi":"10.58782/flmnh.nkup2567","DOIUrl":"https://doi.org/10.58782/flmnh.nkup2567","url":null,"abstract":"The mink (Neogale sp.) has been important species in North American ecosystems and communities for millennia; before European colonization, Indigenous families hunted and trapped mink for their pelts. As part of the euro-colonial fur trade (~1600-1900), wide-spread and intense harvest of mink and other furbearers transformed ecosystems, including the likely extinction of the sea mink (Neogale macrodon) in the Gulf of Maine. The American mink (Neogale vison) has slowly moved into areas that were previously inhabited by the sea mink in coastal and island Maine. The expansion of American mink has been implicated as a potential cause for the declining seabird populations on Maine islands. Here, we use metabarcoding of American mink scat collected in the USFWS Maine Coastal Islands National Wildlife Refuge to evaluate if American mink are predating upon seabirds. Preliminary analysis of mink scat from Petit Manan Island has not implicated mink in bird predation but we did recover host DNA and dietary components including lobster and fish (Cunner). Currently, managers remove American mink from the Refuge islands to protect nesting seabirds but perhaps the seabird populations are returning to population sizes of when sea mink was present in the area. Harvest of furbearers as part of the euro-colonial fur trade may still have implications for ecosystem form and function today.","PeriodicalId":106523,"journal":{"name":"Bulletin of the Florida Museum of Natural History","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134065761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Organisms’ body size is an important biological trait that is related to the environment and constrained by physiology. It is also one of few biological characteristics that can be inferred from fossil specimens. Variation in body size both within and across fossil communities can provide insight into their response to past climatic events, as well as morphological or ecological evolution in specific taxa. Among vertebrates, frogs and toads (Anura) are of particular interest given their sensitivity to environmental variation. Here, we propose a method for estimating body size in toads, one of the most ecologically and taxonomically diverse frog families (Bufonidae) that is cosmopolitan in distribution and contains aquatic, terrestrial, arboreal, and fossorial species. We used computed tomography scans (CT-scans) of 36 living species of toads to digitally segment five bones that are frequently found as fossil (ilium, sacrum, urostyle, humerus, and radioulna). We took nine different measurements on those bones to be used as proxies for body size and for each specimen collected a measurement of body size, snout–urostyle length (SUL). We used ordinary least square regression analysis (OLS) with 95% confidence and prediction intervals to determine if those measurements are useful to estimate body size from isolated bones and in the fossil record. Our regression analyses indicate that these measurements can serve as proxies to estimate body size in bufonids (with coefficients of determination between 0.80–0.95). The measurements with the highest coefficient of determinations are those of the ilium and humeri, both of which are abundant in the fossil record and taxonomically informative. Last, we tested our method on examples of living and fossils toads of North and South America. Our method is the first quantitative approach to estimate size in toads based on isolated bones and enables us to continue to explore the correlation between size and ecology in toads in the past.
{"title":"Body Size Estimation in Toads (Anura: Bufonidae): Applicability to the Fossil Record","authors":"M. Victor, M. Vallejo-Pareja, David Blackburn","doi":"10.58782/flmnh.bnie4350","DOIUrl":"https://doi.org/10.58782/flmnh.bnie4350","url":null,"abstract":"Organisms’ body size is an important biological trait that is related to the environment and constrained by physiology. It is also one of few biological characteristics that can be inferred from fossil specimens. Variation in body size both within and across fossil communities can provide insight into their response to past climatic events, as well as morphological or ecological evolution in specific taxa. Among vertebrates, frogs and toads (Anura) are of particular interest given their sensitivity to environmental variation. Here, we propose a method for estimating body size in toads, one of the most ecologically and taxonomically diverse frog families (Bufonidae) that is cosmopolitan in distribution and contains aquatic, terrestrial, arboreal, and fossorial species. We used computed tomography scans (CT-scans) of 36 living species of toads to digitally segment five bones that are frequently found as fossil (ilium, sacrum, urostyle, humerus, and radioulna). We took nine different measurements on those bones to be used as proxies for body size and for each specimen collected a measurement of body size, snout–urostyle length (SUL). We used ordinary least square regression analysis (OLS) with 95% confidence and prediction intervals to determine if those measurements are useful to estimate body size from isolated bones and in the fossil record. Our regression analyses indicate that these measurements can serve as proxies to estimate body size in bufonids (with coefficients of determination between 0.80–0.95). The measurements with the highest coefficient of determinations are those of the ilium and humeri, both of which are abundant in the fossil record and taxonomically informative. Last, we tested our method on examples of living and fossils toads of North and South America. Our method is the first quantitative approach to estimate size in toads based on isolated bones and enables us to continue to explore the correlation between size and ecology in toads in the past.","PeriodicalId":106523,"journal":{"name":"Bulletin of the Florida Museum of Natural History","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114345809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Many ecosystems today face increasingly frequent and extreme droughts. Small mammals can be harbingers of larger ecological changes, making them critical components for conservation. We use the fossil record to explore how small mammal communities respond to aridity changes. Recent, short-term droughts caused small mammals to increase in evenness, as dominant generalist species suffer severe population fluctuations. It has also been hypothesized that with increasing aridity, herbivore tooth crown heights increase to combat wear. Here, we examine community-level changes, including evenness, hypsodonty, and diet across a series of arid-semiarid cycles. We compare two caves: Natural Trap Cave (NTC), which is open and arid, and Samwell Cave (SC), which is closed and forested. Evenness decreased at both caves from the Late Pleistocene to the Late Holocene. At NTC, dietary generalists were more common in the Pleistocene (61%) with herbivores dominating in the Middle (62%) and Late Holocene (57%). However, at SC generalist taxa increased into the Holocene. The Pleistocene community at NTC had the highest percentage of taxa with low tooth crown heights (42%) halving into the Holocene. Changes in hypsodonty and a shift from generalist to herbivorous taxa at NTC do not align with anticipated responses to aridity, which decreased from the Pleistocene to the recent. Functional relationships of these communities to aridity may be more nuanced than previously thought. Bioavailability of water and local vegetation types at NTC can help parse out these trends. Pleistocene precipitation mostly accumulated during the winter, not aiding plant growth. Thus, generalist mammals who could survive on scant, arid-adapted plants and invertebrates dominated. Precipitation through the Holocene shifted to summer accumulation, allowing plants, like grasses, to colonize and herbivorous taxa to increase in abundance with corresponding shifts to high crowned communities.
{"title":"Changes in Small Mammal Communities Over the Last 25,000 Years Show a Complex Relationship Between Composition, Traits, and Aridity","authors":"Julia A. Schap, J. Meachen, Jenny L. McGuire","doi":"10.58782/flmnh.dykm8350","DOIUrl":"https://doi.org/10.58782/flmnh.dykm8350","url":null,"abstract":"Many ecosystems today face increasingly frequent and extreme droughts. Small mammals can be harbingers of larger ecological changes, making them critical components for conservation. We use the fossil record to explore how small mammal communities respond to aridity changes. Recent, short-term droughts caused small mammals to increase in evenness, as dominant generalist species suffer severe population fluctuations. It has also been hypothesized that with increasing aridity, herbivore tooth crown heights increase to combat wear. Here, we examine community-level changes, including evenness, hypsodonty, and diet across a series of arid-semiarid cycles. We compare two caves: Natural Trap Cave (NTC), which is open and arid, and Samwell Cave (SC), which is closed and forested. Evenness decreased at both caves from the Late Pleistocene to the Late Holocene. At NTC, dietary generalists were more common in the Pleistocene (61%) with herbivores dominating in the Middle (62%) and Late Holocene (57%). However, at SC generalist taxa increased into the Holocene. The Pleistocene community at NTC had the highest percentage of taxa with low tooth crown heights (42%) halving into the Holocene. Changes in hypsodonty and a shift from generalist to herbivorous taxa at NTC do not align with anticipated responses to aridity, which decreased from the Pleistocene to the recent. Functional relationships of these communities to aridity may be more nuanced than previously thought. Bioavailability of water and local vegetation types at NTC can help parse out these trends. Pleistocene precipitation mostly accumulated during the winter, not aiding plant growth. Thus, generalist mammals who could survive on scant, arid-adapted plants and invertebrates dominated. Precipitation through the Holocene shifted to summer accumulation, allowing plants, like grasses, to colonize and herbivorous taxa to increase in abundance with corresponding shifts to high crowned communities.","PeriodicalId":106523,"journal":{"name":"Bulletin of the Florida Museum of Natural History","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115635378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. George, R. Dunn, E. Lindsey, A. Farrell, Glen MacDonald
The California Floristic Province is a biodiversity hotspot. Endemic flora is threatened by climate change, habitat fragmentation and destruction. It is also host to the La Brea Tar Pits (LBTP), which in addition to its famous megafauna, preserves a rare long-term plant macrofossil record with taxonomic resolution to genus and species. The LBTP flora has the potential to provide a comprehensive vegetational history for the Los Angeles Basin and a dynamic baseline for modern conservation efforts. We used accelerator mass spectrometry (AMS) radiocarbon dating to establish a 55 ka timeline of plant presence in Los Angeles, California. We identified and radiocarbon dated 188 plant macrofossils from the La Brea Tar Pits collections. Eight distinct phases of vegetation were identified based on the loss or appearance of key taxa in the timeline. Pairwise similarity was calculated between each identified phase to compare changes to phase species makeup through time. The transition periods between phases were compared to existing climate proxy records to better understand forcings behind vegetation shifts. Two transition periods in the record are of interest to modern conservation efforts. First, fog-dependent closed cone pine species, Pinus muricata and Pinus radiata, become extirpated from the Los Angeles Basin at 48 ka. This disappearance corresponds with a period of extended drought. Second, repeated patterns of juniper species replacement during periods of megadrought, and their eventual extirpation at 12.8 ka, indicate the importance of land management choices in the ability of juniper populations to rebound after drought-induced die-off. Understanding the long-term dynamics of plant community structure in a region is crucial to managing landscapes in the context of global change, and these data are now being leveraged to inform local conservation efforts in the city of Los Angeles.
{"title":"A 55,000-Year Reconstruction of Vegetation in the Los Angeles Basin: Insights into Future Change and a Better Guide for the Present","authors":"J. George, R. Dunn, E. Lindsey, A. Farrell, Glen MacDonald","doi":"10.58782/flmnh.ejtz3128","DOIUrl":"https://doi.org/10.58782/flmnh.ejtz3128","url":null,"abstract":"The California Floristic Province is a biodiversity hotspot. Endemic flora is threatened by climate change, habitat fragmentation and destruction. It is also host to the La Brea Tar Pits (LBTP), which in addition to its famous megafauna, preserves a rare long-term plant macrofossil record with taxonomic resolution to genus and species. The LBTP flora has the potential to provide a comprehensive vegetational history for the Los Angeles Basin and a dynamic baseline for modern conservation efforts. We used accelerator mass spectrometry (AMS) radiocarbon dating to establish a 55 ka timeline of plant presence in Los Angeles, California. We identified and radiocarbon dated 188 plant macrofossils from the La Brea Tar Pits collections. Eight distinct phases of vegetation were identified based on the loss or appearance of key taxa in the timeline. Pairwise similarity was calculated between each identified phase to compare changes to phase species makeup through time. The transition periods between phases were compared to existing climate proxy records to better understand forcings behind vegetation shifts. Two transition periods in the record are of interest to modern conservation efforts. First, fog-dependent closed cone pine species, Pinus muricata and Pinus radiata, become extirpated from the Los Angeles Basin at 48 ka. This disappearance corresponds with a period of extended drought. Second, repeated patterns of juniper species replacement during periods of megadrought, and their eventual extirpation at 12.8 ka, indicate the importance of land management choices in the ability of juniper populations to rebound after drought-induced die-off. Understanding the long-term dynamics of plant community structure in a region is crucial to managing landscapes in the context of global change, and these data are now being leveraged to inform local conservation efforts in the city of Los Angeles.","PeriodicalId":106523,"journal":{"name":"Bulletin of the Florida Museum of Natural History","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121321747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The puzzle-like fit of Africa and South America reflects the tectonically driven opening of the South Atlantic Ocean beginning over 130 mya. By 90 Ma, the North and South Atlantics were conjoined. The introduction of Cretaceous marine reptiles into the central South Atlantic from the north coincides with through-flow in the Equatorial Atlantic Gateway and with increased productivity and upwelling of the Benguela Current. The K-Pg extinction saw the demise of most marine reptiles, but upwelling apparently persisted, evidenced by a growing Cenozoic fossil record of sea turtles and marine mammals from the Angolan coast. Convergent similarities between the Cretaceous marine reptile vertebrate community and the modern vertebrate community of the Benguela Large Marine Ecosystem suggest essentially continuous productivity related to upwelling along the southwest African coast since Cretaceous time. Paleolatitude reconstructions show that predicted positions of coastal upwelling of the Benguela Current have moved south along the coast as Africa drifted northward through the descending limb of the southern Hadley Cell. The Cretaceous and modern faunas were both adapted to a productive upwelling zone. The Cretaceous relict Welwitschia mirabilis is consistent with coastal aridity alongside upwelling. Thus, the sediments of coastal Angola and the fossils they entomb are relevant to conservation paleobiology because they provide a baseline through deep time. Comparisons underscore the resilience of the Benguela Current on the one hand and emphasize human-driven threats to the Benguela Large Marine Ecosystem on the other. Solutions are being sought; for instance, through the evaluation of Ecologically or Biologically Significant Marine Areas (EBSA) in the Benguela Current Large Marine Ecosystem. In Angola, the geologic record of the opening of the South Atlantic, the fossils, public interest, and the value for sustainable development are positive indications for the future.
{"title":"Deep Time Conservation Paleobiology of the Atlantic Jigsaw Puzzle and the Future of the Southwestern Angolan Coast","authors":"L. Jacobs, M. Polcyn, O. Mateus, A. Schulp","doi":"10.58782/flmnh.fior9961","DOIUrl":"https://doi.org/10.58782/flmnh.fior9961","url":null,"abstract":"The puzzle-like fit of Africa and South America reflects the tectonically driven opening of the South Atlantic Ocean beginning over 130 mya. By 90 Ma, the North and South Atlantics were conjoined. The introduction of Cretaceous marine reptiles into the central South Atlantic from the north coincides with through-flow in the Equatorial Atlantic Gateway and with increased productivity and upwelling of the Benguela Current. The K-Pg extinction saw the demise of most marine reptiles, but upwelling apparently persisted, evidenced by a growing Cenozoic fossil record of sea turtles and marine mammals from the Angolan coast. Convergent similarities between the Cretaceous marine reptile vertebrate community and the modern vertebrate community of the Benguela Large Marine Ecosystem suggest essentially continuous productivity related to upwelling along the southwest African coast since Cretaceous time. Paleolatitude reconstructions show that predicted positions of coastal upwelling of the Benguela Current have moved south along the coast as Africa drifted northward through the descending limb of the southern Hadley Cell. The Cretaceous and modern faunas were both adapted to a productive upwelling zone. The Cretaceous relict Welwitschia mirabilis is consistent with coastal aridity alongside upwelling. Thus, the sediments of coastal Angola and the fossils they entomb are relevant to conservation paleobiology because they provide a baseline through deep time. Comparisons underscore the resilience of the Benguela Current on the one hand and emphasize human-driven threats to the Benguela Large Marine Ecosystem on the other. Solutions are being sought; for instance, through the evaluation of Ecologically or Biologically Significant Marine Areas (EBSA) in the Benguela Current Large Marine Ecosystem. In Angola, the geologic record of the opening of the South Atlantic, the fossils, public interest, and the value for sustainable development are positive indications for the future.","PeriodicalId":106523,"journal":{"name":"Bulletin of the Florida Museum of Natural History","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123221030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Victor Rodriguez-Ruano, L. Toth, C. Randall, R. Aronson
Upwelling exerts a major control on coral-reef development in the eastern tropical Pacific (ETP). Upwelling zones exhibit conditions that are detrimental to coral growth, such as low sea-surface temperatures and high levels of turbidity. During the late Holocene, the reefs in the strongly upwelling Gulf of Panamá (GoP) and the weakly upwelling Gulf of Chiriquí (GoC) experienced a climate-driven hiatus in coral growth and reef development, and strong upwelling exacerbated this hiatus in the GoP. Strong upwelling in the GoP is now acting as a buffer against thermal stress, providing a refuge from climatic warming, whereas corals in the GoC are highly vulnerable to increased thermal stress. Using ecological surveys and paleoecological data, we quantified calcification and bioerosion processes for the reefs in these two gulfs to develop carbonate-budget models. We determined the reef-accretion potential (RAP) for reefs in each gulf to project their capacity to keep pace with current and predicted future rates of sea-level rise. On average, reefs in the GoP exhibited an average RAP of 5.5 mm yr-1, which would be enough to keep pace with future rates of sea-level rise if CO2 emissions were reduced under representative concentration pathways (RCPs) 2.6 and 4.5. In contrast, reefs in the GoC exhibited an average RAP of only 0.3 mm yr-1, which is not even enough to keep pace with contemporary rates of sea-level rise in Panamá (1.4 mm yr-1). Furthermore, even if the reefs in either gulf could achieve 100% coral cover, none of them has the capacity to keep pace with RCP 8.5. Although the GoP should support reef development in the near future, reducing greenhouse-gas emissions will be essential to ensure the persistence of accreting reefs and promote the recovery of those vulnerable to net erosion.
{"title":"Climate Change and The Persistence of Coral-Reef Development in Upwelling Zones","authors":"Victor Rodriguez-Ruano, L. Toth, C. Randall, R. Aronson","doi":"10.58782/flmnh.tkof3493","DOIUrl":"https://doi.org/10.58782/flmnh.tkof3493","url":null,"abstract":"Upwelling exerts a major control on coral-reef development in the eastern tropical Pacific (ETP). Upwelling zones exhibit conditions that are detrimental to coral growth, such as low sea-surface temperatures and high levels of turbidity. During the late Holocene, the reefs in the strongly upwelling Gulf of Panamá (GoP) and the weakly upwelling Gulf of Chiriquí (GoC) experienced a climate-driven hiatus in coral growth and reef development, and strong upwelling exacerbated this hiatus in the GoP. Strong upwelling in the GoP is now acting as a buffer against thermal stress, providing a refuge from climatic warming, whereas corals in the GoC are highly vulnerable to increased thermal stress. Using ecological surveys and paleoecological data, we quantified calcification and bioerosion processes for the reefs in these two gulfs to develop carbonate-budget models. We determined the reef-accretion potential (RAP) for reefs in each gulf to project their capacity to keep pace with current and predicted future rates of sea-level rise. On average, reefs in the GoP exhibited an average RAP of 5.5 mm yr-1, which would be enough to keep pace with future rates of sea-level rise if CO2 emissions were reduced under representative concentration pathways (RCPs) 2.6 and 4.5. In contrast, reefs in the GoC exhibited an average RAP of only 0.3 mm yr-1, which is not even enough to keep pace with contemporary rates of sea-level rise in Panamá (1.4 mm yr-1). Furthermore, even if the reefs in either gulf could achieve 100% coral cover, none of them has the capacity to keep pace with RCP 8.5. Although the GoP should support reef development in the near future, reducing greenhouse-gas emissions will be essential to ensure the persistence of accreting reefs and promote the recovery of those vulnerable to net erosion.","PeriodicalId":106523,"journal":{"name":"Bulletin of the Florida Museum of Natural History","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127380385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Caribbean is one of the most well-studied biodiversity hotspots, but the diversity of today’s Caribbean is only a fraction of what once existed there, as natural and anthropogenic processes have contributed to extinction and extirpation across multiple taxonomic groups. Given this long-term history of environmental perturbations and human impacts, paleobiology is well-suited to inform ongoing conservation needs in the Caribbean, which continues to be impacted by habitat degradation, species introductions, and other global change phenomena. I show how fossil, archaeological, and ecological data elucidate patterns of biodiversity loss and resilience, with direct implications for conservation management. While conservation paleobiology has significant potential in the Caribbean, it also faces major challenges in implementation, in part due to colonial histories and practices of parachute science. I summarize how this colonial legacy perpetuates knowledge and resource gaps, and outline ways in which we can move toward an equitable conservation paleobiology. One path forward is through education and partnership with local communities. I highlight my program, NEET Young Innovators, a partnership between the University of Texas at Austin, the Negril Education Environment Trust, the University of the West Indies Mona, and the Jamaican Ministry of Education and Youth. The NEET Young Innovators program develops place-based, experiential curriculum and STEM camps for Jamaican students and teachers. Capitalizing on paleobiology’s status as a “gateway science,” we created and implemented a suite of conservation paleobiology lesson plans in a STEM camp designed to cultivate environmental stewardship and broaden awareness of Caribbean natural history and biodiversity among Jamaican youths. Through integrative research, reflection, and inclusive partnership, paleobiology can guide the conservation, management, and restoration of biodiversity in this critical ecosystem.
{"title":"Characterizing Past Communities to Build Future Ones: Lessons from Caribbean Conservation Paleobiology","authors":"Melissa E. Kemp","doi":"10.58782/flmnh.usbk7399","DOIUrl":"https://doi.org/10.58782/flmnh.usbk7399","url":null,"abstract":"The Caribbean is one of the most well-studied biodiversity hotspots, but the diversity of today’s Caribbean is only a fraction of what once existed there, as natural and anthropogenic processes have contributed to extinction and extirpation across multiple taxonomic groups. Given this long-term history of environmental perturbations and human impacts, paleobiology is well-suited to inform ongoing conservation needs in the Caribbean, which continues to be impacted by habitat degradation, species introductions, and other global change phenomena. I show how fossil, archaeological, and ecological data elucidate patterns of biodiversity loss and resilience, with direct implications for conservation management. While conservation paleobiology has significant potential in the Caribbean, it also faces major challenges in implementation, in part due to colonial histories and practices of parachute science. I summarize how this colonial legacy perpetuates knowledge and resource gaps, and outline ways in which we can move toward an equitable conservation paleobiology. One path forward is through education and partnership with local communities. I highlight my program, NEET Young Innovators, a partnership between the University of Texas at Austin, the Negril Education Environment Trust, the University of the West Indies Mona, and the Jamaican Ministry of Education and Youth. The NEET Young Innovators program develops place-based, experiential curriculum and STEM camps for Jamaican students and teachers. Capitalizing on paleobiology’s status as a “gateway science,” we created and implemented a suite of conservation paleobiology lesson plans in a STEM camp designed to cultivate environmental stewardship and broaden awareness of Caribbean natural history and biodiversity among Jamaican youths. Through integrative research, reflection, and inclusive partnership, paleobiology can guide the conservation, management, and restoration of biodiversity in this critical ecosystem.","PeriodicalId":106523,"journal":{"name":"Bulletin of the Florida Museum of Natural History","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126979891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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