Ecology History Research Articles

Three thousand years of oyster fisheries: a view from Southeast Queensland, Australia

Oysters are an almost ubiquitous presence in coastal archaeological sites globally. Southeast Queensland is no exception, with oysters frequently the dominant taxon in midden deposits. It has been estimated the total number of oysters at Booral Shell Mound in the Great Sandy Strait to be more than 5.9 million individuals. This paper moves beyond just the number of oysters to examine the structure of populations within the deposits at two Southeast Queensland sites, Booral Shell Mound and White Patch 3, from an Applied Historical Ecology approach. In doing so, the nature and sustainability of First Nations marine resource exploitation may be determined. Additionally, environmental factors influencing molluscan population dynamics can be elucidated. Historical accounts provide insights into observed collection practices in the early colonial period, as well as the persistence of First Nations oystering and other marine resource exploitation in the mid-late 19th century in response to participation in the wider economy of early Brisbane. Reasons for the late nineteenth-early Twentieth century collapse of Southeast Queensland oyster populations are examined and attempts to revive the oyster industry reviewed.

Reconstructing the long-term ecological history of Long Island, Furneaux Group (Bass Strait), Lutruwita/Tasmania

The Bass Strait islands are the elevated remnants of a now-submerged continental land bridge that connected the mainland of Australia to Lutruwita/Tasmania during low sea level phases of the Quaternery period. The Furneaux Group is made up of around 100 islands, harbouring a rich diversity of plants derived from glacial refugia and stepping-stone dispersal as millennial-scale climate change altered the land and seascape configuration of the land bridge. Despite the region’s significance, long-term ecological and environmental dynamics of most of these islands remain poorly known. We present the first palaeoecological study of Long Island, a small granite island of the Furneaux group, currently covered by extensive grasslands in the west and patches of forest and woodland in the east and north of the island. We use decadal to centennial-scale resolution palaeoecological evidence for vegetation, animal and fire dynamics, alongside historical accounts of vegetation changes inferred from aerial photo analysis, to develop a comprehensive record of the island’s long-term ecology. Results show that grasslands have been an important feature of the island for at least the last 1000 years, and are reminiscent of Last Glacial Maximum grasslands of the now-submerged Bassian Plain. Both aerial photo analysis and the palaeoecological record show increases in forest cover on the island’s eastern corner over the past four decades. We discuss these ecological dynamics in the context of environmental and climatic shifts. This study emphasises the importance of palaeoecological studies, specifically their value in understanding modern ecosystems in their historic context. This data is critical in understanding the island’s current landscape and how this might change into the future.

Key to sessile gnesiotrochan rotifers: Lacinularia and Sinantherina (Monogononta; Flosculariidae)

Understanding the general biology, biodiversity, ecology, and evolutionary history of organisms necessitates correct identification. Found worldwide in fresh, brackish, and some marine waters, rotifers can be difficult to identify due to their small size, complex characteristics, and dearth of keys to their identification. Moreover, many species lack a hard body wall (i.e., illoricate species), thus they are nearly impossible to identify when preserved. As a result detailed study of many illoricate rotifers is wanting. This is especially acute for the sessile rotifers where quality illustrations, either as line art or light or scanning electron photomicrographs, of adults and trophi is deficient. This leads to a serious impediment in providing a comprehensive accounting for some species. Lacinularia and Sinantherina (Monogononta; Gnesiotrocha; Flosculariidae) are two sessile genera in which the literature provides inadequate treatment. In this contribution we (1) provide simple, dichotomous keys for the identification of all valid species of both genera and (2) present collated information on their morphology thereby detailing where additional research is needed. Both keys focus on easily observable characters of adult female morphology, including features of their coronae, antennae, colony formation behaviors, and presence/absence of eyespots in the adults. We hope that our effort promotes additional research on these two genera, including better documentation of their trophi and general body morphology.

Three centuries of biogeochemical change in a temperate embayment as revealed by sediment core stable isotopes, radiometric dating, and historical ecology

Three centuries of biogeochemical change in a temperate embayment as revealed by sediment core stable isotopes, radiometric dating, and historical ecology

Forecasting sea otter recolonization: insights from isotopic analysis of modern and zooarchaeological populations.

Retrospective datasets offer essential context for conservation by revealing species' ecological roles before industrial-era human impacts. We analysed isotopic compositions of pre-industrial and modern sea otters (Enhydra lutris) to reconstruct pre-extirpation ecology and offer insights for management. Our study focuses on southeast Alaska (SEAK), where sea otters are recolonizing, and northern Oregon, where translocations are being considered. We measured bulk bone collagen δ13C and δ15N values and essential amino acid δ13C values of extirpated sea otters from archaeological contexts, and bulk isotopic values from vibrissae of modern SEAK sea otters. We compare these results with published isotopic data of potential prey and additional archaeological datasets. In SEAK, our data show pre-industrial sea otter populations consumed infaunal bivalves and used soft-sediment (33%) and kelp forest habitats (67%), with sub-regional variation. We anticipate current populations will expand into this historical niche, and conflict with regional traditional/subsistence bivalve fisheries will persist. In northern Oregon, isotopic data from extirpated sea otters indicate past consumption of low trophic level invertebrates and a stronger reliance on kelp forests (88%) rather than soft-sediment habitats, highlighting the importance of kelp forests for future translocations. Our work exemplifies the value of historical ecology in informing conservation strategies for recovering species.

English

Abstract Pacifastacus leniusculus (Dana 1852), the signal crayfish, is a freshwater astacid native to the Pacific Northwest and introduced in western Europe and Japan. Though P. leniusculus populations have been well-studied abroad, where they degrade local habitat and biodiversity, their ecology and natural history are less understood within their native range, where they fill key roles and risk out-competition by exotic crayfish. The present study describes density, morphology, and behavior of resident crayfish in a fourthorder Oregon stream, Tryon Creek, via surveys of nine sites from June–September 2022. Across sites, there was an estimated average P. leniusculus population density of 0.08 m-2, and no exotic crayfish were detected. Amongst crayfish collected (n = 162), total body length (TL) ranged from 13–90 mm, μ = 53 mm. Branchiobdellidans colonized one in four crayfish throughout Tryon Creek, damage to appendages occurred at a rate of 0.45, and the likelihood of both increased with TL. In a case study of Tryon’s Hwy- 43 Culvert, crayfish showed potential signs of stress; across numerous sites, young juveniles resided gregariously. Despite the present study’s novel strides toward native-range P. leniusculus population characterization, further research is encouraged to establish a well-rounded regional baseline.

Historic rewiring of grass flowering time pathways and implications for crop improvement under climate change.

Grasses are fundamental to human survival, providing a large percentage of our calories, fuel, and fodder for livestock, and an enormous global carbon sink. A particularly important part of the grass plant is the grain-producing inflorescence that develops in response to both internal and external signals that converge at the shoot tip to influence meristem behavior. Abiotic signals that trigger reproductive development vary across the grass family, mostly due to the unique ecological and phylogenetic histories of each clade. The time it takes a grass to flower has implications for its ability to escape harsh environments, while also indirectly affecting abiotic stress tolerance, inflorescence architecture, and grain yield. Here, we synthesize recent insights into the evolution of grass flowering time in response to past climate change, particularly focusing on genetic convergence in underlying traits. We then discuss how and why the rewiring of a shared ancestral flowering pathway affects grass yields, and outline ways in which researchers are using this and other information to breed higher yielding, climate-proof cereal crops.

Ecological histories govern social exploitation by microorganisms.

Exploitation is a common feature of social interactions, which can be modified by ecological context. Here we investigate effects of ecological history on exploitation phenotypes in bacteria. In experiments with the bacterium Myxococcus xanthus, prior resource levels of different genotypes interacting during cooperative multicellular development were found to regulate social fitness, including whether cheating occurs. Responses of developmental spore production to experimental manipulation of resource-level histories differed between interacting cooperators and cheaters, and relative fitness advantages gained by cheating after high-resource growth were generally reduced or absent if one or both parties experienced low-resource growth. Low-resource growth also eliminated exploitation in some pairwise mixes of cooperative natural isolates that occurs when both strains have grown under resource abundance. Our results contrast with previous experiments in which cooperator fitness correlated positively with concurrent resource level and suggest that resource-level variation may be important in regulating whether exploitation of cooperators occurs in a natural context.

Diving Deeper: Leveraging the Chondrichthyan Fossil Record to Investigate Environmental, Ecological, and Biological Change

The extensive chondrichthyan fossil record spans 400+ million years and has a global distribution. Paleontological studies provide a foundation of description and taxonomy to support deeper forays into ecology and evolution considering geographic, morphologic, and functional changes through time with nonanalog species and climate states. Although chondrichthyan teeth are most studied, analyses of dermal denticle metrics and soft tissue imprints are increasing. Recent methodological advances in morphology and geochemistry are elucidating fine-scale details, whereas large datasets and ecological modeling are broadening taxonomic, temporal, and geographic perspectives. The combination of ecological metrics and modeling with environmental reconstruction and climate simulations is opening new horizons to explore form and function, demographic dynamics, and food web structure in ancient marine ecosystems. Ultimately, the traits and taxa that endured or perished during the many catastrophic upheaval events in Earth's history contribute to conservation paleobiology, which is a much-needed perspective for extant chondrichthyans. ▪ The longevity and abundance of the chondrichthyan fossil record elucidates facets of ecological, evolutionary, and environmental histories. ▪ Though lacking postcranial, mineralized skeletons, dental enameloid and dermal denticles exquisitely preserve morphology and geochemistry. ▪ Technical advances in imaging, geochemistry, and modeling clarify the linkages between form and function with respect to physiology, diet, and environment. ▪ Conservation efforts can benefit from the temporal and spatial perspective of chondrichthyan persistence through past global change events.

Towards Biocultural Conservation of Chilean Palm Landscapes: Expanding Perspectives from Historical Ecology

The Chilean palm (Jubaea chilensis) is an endangered and culturally important species from central Chile. We studied the Ocoa palm landscape (OPL), which is currently part of a protected area that harbors the largest Chilean palm population where local peasant practices have been excluded and conflict with biodiversity conservation strategies. We explored how human–landscape relationships over time have shaped present conditions and the implications for biocultural conservation. Methods included a review of archaeobotanical and historical records, and a qualitative study focused on local peasants’ perspectives. We reported the uses of J. chilensis and the OPL since pre-Hispanic times. For the last 400 years, these uses have involved important differences between landowners and local peasants in terms of power dynamics, access to the land, and intensity of use. The current palm landscape structure directly responds to past human activities, such as palm felling and agriculture. Also, we explain peasant practices linked to the OPL as ways of resisting cultural homogenization and marginalization associated with reductive conservation approaches and other presses and pulses. Chilean palm conservation can be improved by considering ecological legacies to inform future conservation strategies and adding a biocultural approach that respectfully integrates local peasant knowledge systems and worldviews.

Predation of a rare white-faced tree rat Echimys chrysurus by the Ornate Hawk-eagle Spizaetus ornatus in a lowland Amazonian rainforest

The Echimys chrysurus is a medium-sized rodent of the family Echimyidae found mainly in the Amazon, being rare and difficult to record. In this note, we describe the predation of E. chrysurus by an individual of Ornate Hawk-Eagle, Spizaetus ornatus, in a primary forest area, in western Pará, Brazil. This unprecedented record is an important contribution to the knowledge of the ecology and natural history of both species and provides important insights about their ecology and basic biology.

Avian seed dispersal out of the forests: A view through the lens of Pleistocene landscapes

Abstract Recent evidence supports that, prior to the impact of modern humans, the temperate zone of Europe was not dominated by a closed continuous forest, but consisted of heterogeneous landscapes with grasslands, light woodlands and forests. Until the late Pleistocene, this region held a diverse community of megaherbivores that maintained the open and semi‐open vegetation through grazing and browsing. This new baseline is congruent with the fact that many European woody species are light‐demanding and fail to regenerate in the shaded interiors of temperate forests. Notably, most of these species are dispersed by frugivorous and seed‐caching animals, mostly birds. Nowadays, avian seed dispersers play a key role for the connectivity and expansion of woodland patches in fragmented anthropogenic landscapes. Indeed, avian seed dispersal within and across the deforested matrix is the norm rather than the exception. Here, I reflect on the current patterns of avian seed dispersal in the fragmented anthropogenic landscapes of Europe from a Pleistocene perspective. The aim of this exercise is to discuss linkages between past and present landscapes, seeking an historical understanding of the high spatial complementarity of avian seed dispersal in and out of the forests. Synthesis: I conclude that the spatial patterns of avian seed dispersal in anthropogenic landscapes are congruent with an ecological and evolutionary history with open and semi‐open habitats created and maintained by megaherbivores (ecological memory). By shaping the environmental conditions for millions of years, megaherbivores would have created selective pressures on animals and plants for life in landscape mosaics with forests and open habitats (niche construction). Finally, I discuss differences in landscape patterns today and in the Pleistocene, as well as the generality of these ideas to other biogeographical regions.

Charcoal morphotypes as indicators of fire fuel types and fire events along eight centuries in east‐central Mexico

ABSTRACTThe study of fire and charcoal production in tropical mesophytic ecosystems provides valuable insights into the ecological and climatic history of these systems. The diverse vegetation produces charcoal in various forms and sizes, which influences its dispersion and provides key information about fire dynamics. In this study, we used an approximately 850‐year sedimentary charcoal record extracted from Lake Atezca in east‐central Mexico to reconstruct the history of fire activity, including frequency and intensity. We present innovative information on charcoal morphotypes to interpret fire regimes, identify the types of vegetation burned and analyze human impact. The results reveal a shift in fire regimes during the Spanish Conquest, transitioning from local‐scale burning associated with intensive wood burning for indigenous agriculture to regional‐scale burning characterized by the burning of herbs and grasses linked to the expansion of extensive livestock grazing. This transition is reflected in the decrease of wood charcoal and the increase of smaller particles, as well as in the rise in titanium in the sediments, indicating greater landscape alteration. The evolution of fire regimes in Lake Atezca was driven primarily by human activities since pre‐Hispanic times, although climatic factors, such as severe droughts, may have also influenced fire activity.

Sal Forest in Assam Dooars and Conservation Management: An Ecological History

Sal Forest in Assam Dooars and Conservation Management: An Ecological History

Differential coping capacities underlie the overall resistance of temperate seagrasses to herbivory

AbstractGrazing can impart long‐lasting changes in vegetated ecosystems. How ecosystems respond to herbivory depends on the ecological and evolutionary histories of their foundational species. The overall ecosystem functioning and associated biodiversity depend on these responses but there is still little understanding on how the intensity and duration of herbivory interact and impact vegetated ecosystems. We experimentally tested in the field the responses of three seagrass species with distinct life history traits to increasing intensities of herbivory over time. Specifically, we assessed structural responses (i.e., canopy height and shoot density) to reflect the ecosystem state. Additionally, we used mechanistic models to assess induced and constitutive responses in the different seagrass species. Results show that seagrasses coped with herbivory differentially in relation to their life history traits. Posidonia oceanica (persistent species) was resistant and only registered declines in canopy height, whereas both canopy heigh and shoot density rapidly decreased for Cymodocea nodosa (intermediate‐colonizing species) and Zostera noltei (colonizing species). Seagrasses also differed in the type of structural response, with the colonizing species experiencing reductions in shoot density, and the persistent P. oceanica registering declines in canopy height. After months of exposure to cumulative herbivory, all three species showed signs of stability. Interestingly, none of the species disappeared completely even when exposed to extreme herbivory. Mechanistic models indicate that herbivory‐induced responses are a potential explanation for these patterns. This study suggests that given the long evolutionary history of herbivory, some seagrasses may be remarkably well adapted to both intense and cumulative herbivory.

Reconstructing The Paleoenvironmental And Paleoclimate Variabilities Of The River Niger Basin In Nigeria: Insights From Palynological And Geochemical Proxies.

This study reconstructs the paleoenvironmental and paleoclimate variabilities of the Paleogene-Quaternary River Niger Basin in Nigeria, West Africa, using integrated geochemical (XRF) and palynological proxies, with samples collected from three locations along a downstream gradient: JB (proximal to the Agbaja ironstone formation), AL (midstream), and JL (farthest downstream). Geochemical analysis reveals distinct trends influenced by the proximity to the Agbaja ironstone. JB sediment exhibits high Fe₂O₃ (20.538 wt.%) and MnO (0.425 wt.%) concentrations, reflecting localised ferruginous inputs and tropical weathering associated with the ironstone. Downstream, AL and JL show increasing SiO₂ content (63.546 wt.% in JB to 87.215 wt.% in JL), indicating progressive sediment dilution, greater contributions from quartz-rich sources, and prolonged transport. The palynological analysis identifies diverse microfossils, including Laevigatosporites sp., Retitricolporites irregularis, Diatom frustules, and Botryococcus braunii, providing insights into vegetation dynamics and hydrological fluctuations. Rainforest indicators, such as Sapotaceae and Proxapertites cursus, signify wetter interglacial periods, while grassland taxa like Monoporites annulatus and charred gramineae cuticles denote arid phases. Algal taxa (Pediastrum sp., Diatom frustules) reflect freshwater conditions, whereas mangrove-associated species (Acrostichum aureum, Echiperiporites sp.) highlight episodes of brackish influence during sea-level rises. This bi-proxy approach reveals alternating humid and arid phases influenced by Quaternary climate oscillations. These changes have affected vegetation cover, sediment transport, and depositional settings. The findings enhance our understanding of the paleoenvironmental evolution of West Africa, providing valuable context for regional climate models and sedimentary processes. This study makes a significant contribution to the findings on Quaternary climate variability and its impact on the ecological and geological history of the River Niger basin in Nigeria, West Africa.

Species identification of modern and archaeological shark and ray skeletal tissues using collagen peptide mass fingerprinting

IntroductionElasmobranchs, such as sharks and rays, are among the world’s most endangered vertebrates, with over 70% loss in abundance over the past 50 years due to human impacts. Zooarchaeological baselines of elasmobranch diversity, distribution, and exploitation hold great promise for contributing essential historical contexts in the assessment of contemporary patterns in their taxonomic diversity and vulnerability to human-caused extinction. Yet, the historical ecology of elasmobranchs receives relatively less archaeological attention compared to that of ray-finned fishes or marine mammals, largely due to issues of taxonomic resolution across zooarchaeological identifications.MethodsWe explore the use of Zooarchaeology by Mass Spectrometry (ZooMS) for species identification in this unstudied group, using an archaeological case study from the marine environments of the Florida Keys, a marine biodiversity hotspot that is home to an array of elasmobranch species and conservation efforts. By comparison with 39 modern reference species, we could distinguish 12 taxa within the zooarchaeological assemblage from the Clupper archaeological site (Upper Matecumbe Key) that included nine sharks, two rays and a sawfish.Results and discussionThe results indicate that, through additional complexity of the collagen peptide mass fingerprint, obtained due to the presence of the cartilaginous type II collagen, ZooMS collagen peptide mass fingerprinting provides exceptionally high taxonomic resolution in this group, yielding species-level identifications in all cases where sufficient reference material was used. This case study also highlights the added value of ZooMS for taxa that are more difficult to distinguish in zooarchaeological analyses, such as vertebrae of the Atlantic sharpnose shark (Rhizoprionodon terraenovae) and the hammerhead sharks (Sphyrna spp.) in the Florida Keys. Therefore, the application of collagen peptide mass fingerprinting to elasmobranchs offers great potential to improve our understanding of their archaeological past and historical ecology.

Historical ecology reveals the "surprising" direction and extent of shifting baselines for the Florida manatee (Trichechus manatus latirostis).

Historical data are often overlooked in risk assessments and recovery plans for marine animals, resulting in the "shifting baselines." Historical ecological studies demonstrate the "surprising" extent to which contemporary assumptions misrepresent premodern baselines. The Florida manatee, a subspecies of the West Indian manatee found primarily in Florida, USA, faces several existential threats, but risk assessments and recovery targets for the species are hindered by poor understanding of historical baselines. We conducted systematic and opportunistic reviews of archaeological and historical records of manatee occurrence in Florida, USA. Our data reveal that manatee populations in Florida were very small in the Precolonial and Colonial Periods, possibly representing infrequent in-migration from the Caribbean during favorable climate conditions. Manatees expanded in number and range across the Florida peninsula during the Territorial/Early Statehood and Early Modern Periods, first northward on the Atlantic Coast and later along the coast of the Gulf of Mexico. These expansions track increasing human populations, associated anthropogenic landscape alterations, and social and policy changes. Historical ecology is critical for "shaping a better Anthropocene" for humans and manatees in Florida.

Ecology and life history predict avian nest success in the global tropics

Nest predation rates critically influence avian biodiversity and evolution. In the north temperate zone, increased nest failure along edges of forest fragments is hypothesized to play a major role in the disappearance of bird species from disturbed landscapes. However, we lack comprehensive syntheses from tropical latitudes, where biodiversity is highest and increasingly threatened by habitat fragmentation and disturbance. We assembled data from five decades of field studies across the global tropics (1,112 populations of 661 species) and used phylogenetic models to evaluate proposed predictors of nest success. We found significant effects of several traits, including adult body mass and nest architecture. Contrary to results from many temperate locations, anthropogenic habitat disruption did not consistently reduce nest success; in fact, raw nest success rates were lower in large tracts of primary forest than in disturbed or fragmented landscapes. Follow-up analyses within species, using a subset of 76 species for which we had estimates of nest survival in habitats with different levels of disruption, confirmed that neither disturbance nor fragmentation significantly influenced nest success. These results suggest that nest predation alone cannot explain observed declines in avian biodiversity in tropical forest fragments, raising new questions about the demographic processes that drive extinction in the tropics.

Indigenous use and conservation of harbor seals (Phoca vitulina) at Yakutat, Alaska since the sixteenth century

Sustainable Indigenous resource use reflects balance between animal populations and levels of human consumption, influenced by natural cycles of faunal abundance, community size and subsistence needs, procurement technologies, and the requirements of trade or commodity production. Sustainability is “epiphenomenal” when animal populations are preserved, and community needs met, without deliberate measures to prevent overharvesting. Alternatively, Indigenous conservation—cultural practices that moderate use of a resource to prevent its depletion—may play a determinative role. In this study from the Tlingit community of Yakutat, Alaska in the Northwest Coast cultural region, we interweave Indigenous and scientific perspectives to trace the use and conservation of harbor seals (Phoca vitulina) from before Western contact through the Russian and American colonial periods to the present. Harbor seals, which concentrate in large numbers at a summer ice floe rookery near Hubbard Glacier, are the community's most important subsistence food and a key to its culture and history. The Smithsonian Institution and Yakutat Tlingit Tribe undertook collaborative research in historical ecology and archaeology in 2011–2014 including oral interviews with elders and subsistence providers, excavations at sealing sites, archaeofaunal analysis, historical and archival research, and consideration of climate cycles and biological regime shifts that influence the harbor seal population in the Gulf of Alaska. We compare technologies and hunting practices before and after Western contact, estimate harvest levels in different periods, and evaluate the effectiveness of traditional conservation practices that included hunting quotas enforced by clan leaders and the seasonal delay of hunting with firearms to prevent abandonment of the rookery by the seal herd.