Paleoecological Studies Research Articles

Towards the understanding the impact of fire on the lower montane forest in the Polish Western Carpathians during the Holocene

In this article, we aim to decipher the effect of fire on the changes in the forest composition during the past ca. 10,700 years in the lower montane zone of the Polish Western Carpathians (Beskid Makowski Mountains, Central Europe). The results revealed that during the Early Holocene, the Ulmus population (a fire-intolerant taxon) was well-established under high fire activity, induced by the prominent presence of Pinus sylvestris. Ulmus probably was only slightly affected by fire because it occurred in wetter habitats, whereas P. sylvestris occupied drier ones. The final disruption of Pinus sylvestris–Betula woodlands were linked to a declining trend in fire activity but stable fire frequency, combined with the rapid expansion of Corylus avellana at ca. 9680 cal. BP. A low magnitude of fire disturbance with an increasing fire frequency supported the expansion of Tilia cordata (a fire-sensitive species) and C. avellana (a fire-adapted species) against Picea abies during ca. 7650–7270 cal. BP. Cooler and wetter conditions during the 4.2 and 2.8 ka. BP climatic events probably forced humans to migrate to higher altitudes, which contributed to fire-induced deforestation of a small area, which in turn, together with climatic changes, stimulated the expansion of Abies alba and Fagus sylvatica (both are fire-intolerant taxa). The discontinuities in the deposits of mire might be related to the global climatic changes of the 8.2 and 4.2 ka. BP events and extended deforestations linked to the Wallachian colonisation during the Middle Ages. Such depositional gaps, when remaining undetected during palaeoecological studies, may distort the reconstruction process of fire–vegetation relationships. In this study, we unequivocally show that small disturbances in fire may be an advantageous factor for the expansion of tree taxa devoid of morphological–physiological fire traits.

Drought, freshwater availability and cultural resilience on Easter Island (SE Pacific) during the Little Ice Age

After decades of human-deterministic explanations for the collapse of the ancient Rapanui culture that inhabited Easter Island (Rapa Nui) before European contact (1722 CE), paleoecological studies developed over the last decade have provided sound evidence of climate changes and their potential socioecological impacts. Especially significant is the occurrence of a century-scale drought (1570–1720 CE) during the Little Ice Age (LIA). Freshwater is a critical resource on Easter Island that heavily depends on rain, which maintains the only three permanent surficial freshwater sources on the island: two lakes (Rano Kao and Rano Raraku) and a marsh (Rano Aroi). Under these conditions, the LIA drought could have significantly affected human life; however, the Rapanui society remained healthy, showing remarkable resilience. There are two main hypotheses on how the ancient Rapanui could have obtained freshwater to guarantee their continuity. One of these hypotheses proposes that Lake Kao was a permanent source of freshwater, even during the LIA drought, which led to some intraisland cultural and population reorganizations. The coastal groundwater hypothesis dismisses the use of lakes and other surficial freshwater sources to maintain the water-stressed Rapanui population and contends that the only routine freshwater sources during the LIA drought were the abundant and widespread coastal seeps fed by fresh/brackish groundwater. The pros and cons of these two hypotheses are discussed on the basis of the available archeological and paleoecological evidence, and it is concluded that given the present state of knowledge, neither can be rejected. Therefore, these two proposals could be complementary rather than mutually exclusive.

Pre-burial taphonomic imprints on drilling intensity: a case study from the recent molluscs of Chandipur, India

ABSTRACT Palaeoecological studies of drilling intensity (DI), drawing ecological and evolutionary inferences, generally assume that drilled and undrilled specimens are equally preserved in the fossil record, because of the fact that the presence of drillholes does not affect preservation potential during sediment compaction. However, another facet that has not been studied conclusively is the taphonomic imprint on DI in a pre-burial scenario. If drillholes add weakness to a shell’s mechanical strength, drilled valves may preferentially be broken during post-mortem transportation, before its’ burial within sediment. In the present study, we test this hypothesis with a dataset involving DI and taphonomic status of two bivalve, Donax scortum and Mactra luzonica and two gastropod, Natica tigrina and Turricula javana species from Chandipur, India. Taphonomic status of each specimen is determined by relative preservation of its’ morphological characters. In case of both bivalves and gastropods, DI is found to be highest among the best preserved specimen and, thereafter, declines with increasing taphonomic degradation. When shell size is included in analyses, DI still shows an inverse relation with taphonomic alteration. This observed inverse relationship between drilling intensity and taphonomic imprint suggest that drilled shells may be vulnerable to breakage by pre-burial taphonomic processes.

Non-destructive analysis of pathological belemnite rostra by micro-CT techniques

Previously, palaeopathological features of fossil hardparts were often difficult to interpret because it was impossible to decipher their internal structure without destroying the specimens. We applied high-resolution computedtomo graphy (CT) to document such internal structures. This enabled us to describe a variety of pathologies of Jurassic and Cretaceous belemnite rostra. The examined rostra have been assigned to the taxa ?Acrocoelites sp., Belemnello camax spp., Belemnitella sp., Duvalia emerici, Goniocamax sp., Gonioteuthis spp., Hibolithes jaculoides, Neoclavibelus sp., and Pseudobelus sp. The studied pathologies comprise rostra with two apices, bulges, pearls, broken juvenile rostra, highly porous rostra with abnormal growth increments, blunt-rostra, rostra with callus-like structures, and bent- or knee-shaped rostra. In one rostrum the apex has been turned towards the anterior (alveolus) during ontogeny. Additionally, computed-tomography data were used to document diagenetic alterations of the rostra such as silification, sedimentary infill, pyrite formation. Specimens can also be tested for the presence or absence of internal elements (septa, siphuncle) and surface features. Palaeoecological studies clearly benefit from the application of computed-tomography to gain high resolution images of otherwise invisible internal features of extinct organisms, as demonstrated herein. Key words: Belemnitida, palaeopathology, rostra, micro computed-tomography, diagenesis, Jurassic, Cretaceous, Germany.

A review of lake palaeoecology research in China

湖泊古生态学是古湖沼学的一个主要分支学科，主要通过沉积记录中的各种生物化石指标分析，重建不同时空尺度的湖泊生态系统演化过程，回答生态学、全球变化和环境管理应用方面的议题.本文回顾了国内外湖泊古生态研究的发展历程，在介绍湖泊古生态系列指标和研究基本原理基础上，着重评述了过去20 a来我国湖泊古生态研究取得的主要进展和成果，包括：（1）建立了基于多种生物和生物标记化合物指标进行古气候环境要素（温度、盐度、水体总磷等）定量重建的系列转换函数模型；（2）重点揭示了不同地质历史时期和近百年来湖泊生态环境演变的规律，及其对自然和人为驱动的响应特征与机理；（3）利用古生态记录诊断了湖泊生态系统突变模式与早期信号特征，定量揭示了湖泊生物群落演替与生态系统弹性损失的关系.上述成果为湖泊环境管理和治理提供了重要依据.本文最后对我国湖泊古生态研究进行了展望，提出了今后研究的重点方向.;Lake palaeoecology is an important branch of palaeolimnology, which aims to reconstruct the evolution of lake ecosystems on various spatiotemporal scales, and answer the questions of ecology, global change and environmental management through multiple subfossil biological proxies in the sedimentary records. This paper reviewed the history of palaeoecology studies at home and abroad. After introducing the fundamental principles of lake palaeoecology, this paper further elaborated the main progresses and achievements of palaeoecology research in China in the past 20 years, including (1) the transfer function models to quantitatively reconstruct past climate and environmental parameters (temperature, salinity, total phosphorus, etc.) based on a variety of biological and biomarker compound proxies were established; (2) the laws of the lake ecological environment evolution in different geological historical periods and in the past century, and its response characteristics and mechanisms to the natural and anthropogenic driving forces were revealed; (3) the palaeoecological records were used to diagnose the regime shift patterns and early signal characteristics of lake ecosystems, and the relationships between the biological structures and resilience loss of lake ecosystems were quantitatively revealed. These results provide important basis for lake environmental management and governance. In the end, the paper makes a prospect for the study of lake palaeoecology in China and puts forward the emphasis for the future studies.

The Last Glacial and Holocene history of mountain woodlands in the southern part of the Western Carpathians, with emphasis on the spread of Fagus sylvatica

The Western Carpathians have recently been examined in several palaeoecological studies. However, some of their parts remain underexplored in terms of the Holocene history of mountain woodlands. We analysed an 8000-year-old peat sequence from the southern part of the Western Carpathians (the Bykovo site) for pollen, needles and stomata, and reviewed the data on the occurrence and spread of beech since the Last Glacial times in order to put results from Bykovo into the context of the whole Western Carpathians. For pre-industrial times, we reconstructed mixed beech–fir or beech–fir–spruce woodlands in zonal habitats, noble hardwood woodlands on screes, and spruce woodlands in peaty and wet habitats. A meta-analysis of available pollen data for beech revealed that a few sites in Pannonia and on the southern Carpathian fringes reached beech pollen abundances exceeding 0.5% at the very beginning of the Holocene (12–10 cal BP). Moreover, the pattern of reaching greater pollen abundance limits showed a clear south-to-north gradient starting in the Pannonian lowland. Therefore, the direction of the spread of beech based on pollen abundances and the absence of beech macrofossil evidence during the Last Glacial Maximum do not support local glacial refugia of beech directly in the Western Carpathians. The timing of local beech occurrence (empirical pollen limit of 1.4–2%) and its expansion (rational pollen limit of up to 5%) at the Bykovo site fits well this gradual spread of beech from the south. The first period of beech spread in the Bykovo area around 6250 cal BP coincides well with the period of increased precipitation between 6100 and 6800 cal BP, as reconstructed by different proxies (e.g. stable isotopes) for the Western Carpathians.

Palynological analysis of dental calculus from Pleistocene proboscideans of southern Brazil: A new approach for paleodiet and paleoenvironmental reconstructions

The proboscidean Notiomastodon platensis is widely recognized in the Pleistocene of Brazil, but direct evidence for its feeding behavior is scant. In this paper, we report palynological assemblages preserved in dental calculi to infer dietary preferences and habitats. Molar specimens (m1 and M3/m3) with significant calculus accumulation were examined from localities along the Coastal Plain (CPRS) and the Campanha region (western state in Pampa biome) in Rio Grande do Sul state, southern Brazil. Palynomorphs obtained from calculus were identified with light microscopy, and we applied species distribution modelling (SDM) for arboreal/shrub pollen taxa to investigate the environmental contexts for proboscideans during the Last Interglacial (LIG, 120 ka BP) and Last Glacial Maximum (LGM, 21 ka BP). Pollen assemblages indicate a generalist diet for N. platensis, and corroborate previous paleoecological studies. N. platensis from CPRS showed two patterns: the subadult individual was a specialized browser in wooded habitats, inferred from pollen taxa dominated by arboreal species (mainly Myrtaceae), while mature/senile adult individuals were dominantly grazers to mixed-feeders in open habitats inferred from herbaceous pollen (mainly Cyperaceae) mixed with woody elements. For the Campanha region, diet interpretation is difficult due to the absence of pollen; however, Poaceae phytoliths indicate that grasses may have been important food items, notably pooid C3 grasses. N. platensis potentially accessed a more heterogeneous environment with mixed open grasslands and forests around the LIG interval because of the larger extension of forest at the time. Grassland landscapes could have been more foraged by proboscideans around the LGM given the dry and cold climate conditions, which resulted in a northward retraction of forest.

Intertwined effects of climate and land use change on environmental dynamics and carbon accumulation in a mangrove-fringed coastal lagoon in Java, Indonesia.

The identification and quantification of natural carbon (C) sinks is critical to global climate change mitigation efforts. Tropical coastal wetlands are considered important in this context, yet knowledge of their dynamics and quantitative data are still scarce. In order to quantify the C accumulation rate and understand how it is influenced by land use and climate change, a palaeoecological study was conducted in the mangrove-fringed Segara Anakan Lagoon (SAL) in Java, Indonesia. A sediment core was age-dated and analyzed for its pollen and spore, elemental and biogeochemical compositions. The results indicate that environmental dynamics in the SAL and its C accumulation over the past 400years were controlled mainly by climate oscillations and anthropogenic activities. The interaction of these two factors changed the lagoon's sediment supply and salinity, which consequently altered the organic matter composition and deposition in the lagoon. Four phases with varying climates were identified. While autochthonous mangrove C was a significant contributor to carbon accumulation in SAL sediments throughout all four phases, varying admixtures of terrestrial C from the hinterland also contributed, with natural mixed forest C predominating in the early phases and agriculture soil C predominating in the later phases. In this context, climate-related precipitation changes are an overarching control, as surface water transport through rivers serves as the "delivery agent" for the outcomes of the anthropogenic impact in the catchment area into the lagoon. Amongst mangrove-dominated ecosystems globally, the SAL is one of the most effective C sinks due to high mangrove carbon input in combination with a high allochthonous carbon input from anthropogenically enhanced sediment from the hinterland and increased preservation. Given the substantial C sequestration capacity of the SAL and other mangrove-fringed coastal lagoons, conservation and restoration of these ecosystems is vitally important for climate change mitigation.

PH-dependent silicon release from phytoliths of Norway spruce (Picea abies)

Accurate evaluation of the preservation state of fossil phytoliths in glacial lake sediments is important, as these microfossils are often used in paleoecological and archaeological studies. The characteristic phytolith type of the Norway spruce (Picea abies [L.] Karst.) needle is a potential keystone in paleoecological studies. In this laboratory study, we investigated dissolution of Picea abies blocky type phytoliths, to simulate dissolution processes in sediments and soils and create reference material to compare with fossil phytoliths. Intact needles, needle ash, diatomite and silica gel were treated with Britton–Robinson buffer solutions at pH values from 2 to 12 for 22 days. Silicon was measured by microwave plasma atomic emission spectrometry. Treatment effects were evaluated on longitudinal cuts of needles under a stereomicroscope and on phytolith assemblages from needles using a light microscope. Surfaces of treated phytoliths were investigated by scanning electron microscope and elemental analysis of phytoliths was determined by energy dispersive X-ray fluorescence. Dissolution of silicon in spruce needles was inhibited between pH 8.0 and 11.1. Needle tissue protects phytoliths from erosion processes at this alkaline pH range. Most dissolved silicon appeared to originate from the phytolith surfaces and the silica matrix of the apoplast in the tissues, with less from complete dissolution of phytoliths. Our experiment suggests that extraneous metal elements are incorporated into the silica structure during the dissolution process. Thus, higher element content is an effect of partial dissolution rather than a cause of dissolution. Ultrastructure of the surface of Picea-blocky type phytoliths, namely disappearance of the globular structure, may be useful to assess the intensity of destructive processes in sediments. Our experimental treatments indicate that characteristic Picea-blocky phytoliths in needles can be well-preserved, depending on circumstances in sediments. Further micro-analytical measurements will make these needles promising tools for paleoenvironmental reconstructions.

A 15,400-year long record of vegetation, fire-regime, and climate changes from the northern Patagonian Andes

Paleoecological studies from the northern Patagonian Andes (40–44°S) have identified past changes in vegetation, fire regimes and paleoclimate since the last glaciation, including variations in strength and position of the Southern Westerly Winds (SWW). The extent to which records west and east of the Andes provide a congruent paleoclimatic history, however, has not been explored in detail in the literature. Physical and biological contrasts are evident between these regions today and are to be expected in paleoclimate reconstructions. In this context, we present pollen and charcoal records from sediment cores collected in Lago Espejo, a small closed-basin lake located in the core sector of the northern Patagonian Andes that spans uninterrupted the last ∼15,400 years. Following glacier withdrawal, the vegetation surrounding Lago Espejo features scattered Nothofagus woodlands, including relatively thermophilous rainforest trees between ∼15,400 and 14,400 cal yr BP. The disappearance of these trees and an abrupt rise in Nothofagus at ∼14,400 cal yr BP mark the establishment of closed-canopy forests during the Antarctic Cold Reversal, followed by increases in the cold-tolerant hygrophilous conifer Podocarpus nubigena during the Younger Dryas (∼12,700–11,500 cal yr BP). The Holocene vegetation consists of Nothofagus-dominated forests with modest variation in composition and structure until the present, attesting to the resilience of these forest communities to climate change and natural disturbance regimes. Rapid deforestation, anthropogenic fires and the establishment of artificial meadows with exotic herbs introduced by Europeans at ∼150 cal yr BP, triggered a rapid, large-magnitude landscape transformation unprecedented in the last 14,000 years. The timing and structure of vegetation changes revealed by the Lago Espejo record suggest that changes in the SWW were the main driver of vegetation and fire regimes in the Andes of northern Patagonia over the last 15,400 years. Comparison between multiple reconstructions from northern Patagonia reveals overall coherent vegetation and fire regime changes in the western and Andean sectors, and a spatially variable and more divergent behaviour in sites located further east. This spatial patter is akin to the present-day correlation between precipitation and SWW in this region.

A chronostratigraphic framework for the Upper Jurassic Morrison Formation, western U.S.A.

ABSTRACTThe fluvial, overbank, and lacustrine deposits of the Upper Jurassic Morrison Formation of the Western Interior, U.S.A. have been intensively studied due to their diverse and well-preserved dinosaurian fauna, and the presence of economic quantities of uranium and vanadium ores. The formation crops out over 12 degrees of latitude and 1.2 million km2, and is an excellent case study for the examination of paleoecology, community structure, and evolutionary dynamics at a time in Earth's history when the climate was significantly warmer than today. However, paleoecological studies have been hampered by lack of correlation across the formation. Assuming a primarily tectonic control on fluvial architecture, we propose the first chronostratigraphic framework of the formation, which is based on sequence stratigraphy, magnetostratigraphy, and radiometric dating. The formation can be divided into three sequences each represented by a period of degradation followed by aggradation. This chronostratigraphic framework indicates that the formation youngs to the north, and was deposited over about 7 million years during the late Kimmeridgian and Tithonian. This framework provides a foundation for future sedimentological, stratigraphic, and paleobiological studies of the iconic dinosaurian fauna known from the Morrison.

Carbon isotope ecology of gymnosperms and implications for paleoclimatic and paleoecological studies

Abstract Plants are direct recorders of the environmental conditions in which they were growing through their carbon assimilation. Both δ13Cleaf (measured C isotopic composition of the leaf) and Δleaf (isotopic discrimination from δ13Catm by the leaf) values have been proposed to reflect a variety of environmental conditions including MAT, MAP, latitude, elevation, [CO2], and δ13Catm. Herein, we examine three sets of data from gymnosperms with long fossil records as well as selected co-occurring angiosperms to compare responses to potential environmental controls. The first dataset comprises species growing across a wide array of climatic and environmental conditions to examine MAT, MAP, latitude, and elevation. Among those potential environmental factors, none exhibits a strong control on either δ13Cleaf or Δleaf at the family, genus, or species level for either the focal gymnosperms or most of the co-occurring angiosperms. This result holds whether temperature or precipitation are considered annually or seasonally. Plant meta-analyses that have suggested a strong relationship between MAP and δ13Cleaf or Δleaf can instead be interpreted as reflecting constant Δleaf for individual species over their environmental occurrence ranges where individual ecosystems are made up of various species at different points along their individual MAP tolerance. The second dataset comes from an array of species all growing under the same environmental conditions. While differences in δ13Cleaf or Δleaf are small at the family level, at the genus and species level variation is much larger. This suggests that for any paleo-proxy reconstruction, accurate plant identification is critical to selecting the appropriate Δleaf. It also may indicate that there is an evolutionary component to measured Δleaf values, with large differences potentially between early-divergent and derived lineages. The third dataset is derived from herbarium collections of species that span the period of Industrialization (1850-present). During this time period CO2 levels have increased by ~50% and δ13Catm has shifted by >2‰ due to the burning of isotopically more negative fossil fuels. All of the historical records show that plants shifted their δ13Cleaf value, tracking the δ13Catm changes, but they did not change their Δleaf values. This contrasts strongly with some experimental results based on fast-growing herbaceous angiosperms and suggests either that there are fundamental differences between woody and herbaceous plants and/or that gymnosperms respond differently to increased CO2 than angiosperms. Finally, a brief case study is presented that examines how water use efficiency (represented by ci/ca) changed in response to elevated atmospheric CO2 levels in the Eocene to Miocene. Both Thuja and Metasequoia substantially increase their ci/ca ratios during the highest CO2 levels in the Eocene and decreased them in response to falling atmospheric CO2 during the Miocene. This suggests that the compiled Δleaf values described herein can be used to improve a variety of paleo-proxies for atmospheric CO2 levels and for plant responses to changing atmospheric stressors.

The Toledo Mountains: A Resilient Landscape and a Landscape for Resilience? Hazards and Strategies in a Mid-Elevation Mountain Region in Central Spain

The Toledo Mountains are a mid-elevation mountain range that separates the Tagus and Guadiana basins in the central area of the Iberian Peninsula. The location of these mountains allows the development of typical Mediterranean vegetation with some Atlantic influence. Consequently, typical broadleaved evergreen Mediterranean vegetation currently dominates the regional landscape, with the remarkable presence of more mesophilous species in sheltered and more humid microsites such as gorges (e.g., Prunus lusitanica, Taxus baccata, Ilex aquifolium) and mires/bogs (e.g., Betula pendula susbp. fontqueri, Erica tetralix, Myrica gale). Palaeoecological studies in these mountains are essential to understand the long-term ecology and original distribution of these valuable communities and are key to assess their resilience. Understanding the hazards and opportunities faced in the past by the plant communities of the Toledo Mountains is necessary to enhance the management and protection of those species currently threatened. This study focuses on El Perro mire, a peatland on the southern Toledo Mountains (central Spain) where climatic variability has played a major role in landscape dynamics at multi-decadal to millennial timescales. Climatic events such as the 4.2 ka cal. Before Present (BP) or the Little Ice Age triggered relevant landscape changes such as the spread and latter decline of birch and hazel forests. Human communities also seemed to be affected by these events, as their resilience was apparently jeopardized by the new climatic conditions and they were forced to find new strategies to cope with the new scenarios.

Fly palaeo-evo-devo: immature stages of bibionomorphan dipterans in Baltic and Bitterfeld amber.

Larvae of flies and gnats (Diptera) form a crucial component of many terrestrial and freshwater ecosystems in the extant biosphere. Larvae of Diptera play a central role in water purification, matter and energy transfer in riparian ecosystems in rivers, carbon cycling in lakes and forests as well as being major decomposers of dead organic matter. Despite all these important roles, dipteran larvae are most often ignored in palaeoecological studies, due to the difficulty of the taxonomic identification of fossil larvae, but also due to the perceived importance of adult dipterans in palaeoentomological and taxonomic studies. Despite that, much information on palaeoecosystems can be gained from studying fossil dipteran larvae, in particular for well preserved specimens from fossil resins (ambers and copals). Since ambers are selectively preserving fauna of trunks and leaf litter, it allows us to learn a lot about xylophages and saprophages of amber forests, such as Eocene Baltic amber forest. Here we present immature stages (larvae and pupae) of the dipteran ingroup Bibionomorpha, from Baltic and Bitterfeld amber forests. We have recorded at least four different larval morphotypes, one with four distinct instars, and at least three pupal morphotypes. One larva is recognised as a new species and can be interpreted either as a representative of a highly derived ingroup of Bibionidae or as a sister species to Bibionidae. Also represented by single larval specimens are the groups Pachyneura (Pachyneuridae) and Sylvicola (Anisopodidae). The majority of the recorded specimens are representatives of the group Mycetobia (Anisopodidae). Due to the abundance of immature stages of Mycetobia, we have been able to reconstruct the number of larval stages (4) and relative growth rate of these fossil dipterans. We discuss implications of these finds.

Extinction in the Anthropocene.

Samuel Turvey and Jennifer Crees introduce the effects of humans on biodiversity.

Combining Contemporary and Paleoecological Perspectives for Estimating Forest Resilience

In the face of dramatic climate change and human pressure acting on remaining forest areas across tropical, temperate and boreal biomes, there has emerged a coordinated effort to identify and protect forests that are currently considered “intact”. These forests are hypothesized to be more resilient to future abiotic perturbations than fragmented or degraded forests and, therefore, will provide more reliable carbon storage and/or biodiversity services into an uncertain future. Research in the fields of contemporary and palaeoecology can offer valuable insights to enhance our ability to assess resilience of forests and whether these would be comparable across forest biomes. Contemporary ecological monitoring has been able to capture processes acting over the short-to-medium term, while palaeoecological methods allow us to derive insights of the long-term processes affecting forest dynamics. Recent efforts to both identify intact forests, based on area definitions, and assess vegetation climate sensitivity globally have relied on satellite imagery analysis for the time period 2000-2013. In this paper, we compare these published datasets and do find that on average intact forests in boreal and tropical biomes are less sensitive to temperature and water availability, respectively; however, the patterns are less clear within biomes (e.g. across continents). By taking a longer perspective, through palaeoecology, we present several studies that show a range of forest responses to past climatic and human disturbance, suggesting that short-term trends may not be reliable predictors of long-term resilience. We highlight that few contemporary and palaeoecology studies have considered forest area when assessing resilience and those that have did find that smaller forest areas exhibited greater dynamism in species composition, which could be a proxy for declining resilience. Climatic conditions in the Anthropocene will be pushing forest systems across biomes into novel climates very rapidly and with current knowledge it is difficult to predict how forests will react in the immediate term, which is the most relevant timeframe for global efforts to reduce carbon emissions.

Relating dung fungal spore influx rates to animal density in a temperate environment: Implications for palaeoecological studies

The management of the remainder of Europe’s once extensive forests is hampered by a poor understanding of the character of the vegetation and drivers of change before the onset of clearance for farming. Pollen data indicate a closed-canopy, mixed-deciduous forest, contrasting with the assertion that large herbivores would have maintained a mosaic of open grassland, regenerating scrub and forested groves. Coprophilous fungal spores from sedimentary sequences are increasingly used as a proxy for past herbivore impact on vegetation, but the method faces methodological and taphonomical issues. Using pollen trap data from a long-running experiment in Chillingham Wild Cattle Park, UK, we investigate the first steps in the mechanisms connecting herbivore density to the incorporation of fungal spores in sediments and assess the effects of environmental variables on this relationship. Herbivore utilisation levels correlate with dung fungal spore abundance. Chillingham is densely populated by large herbivores, but dung fungal spore influx is low. Herbivores may thus be present on the landscape but go undetected. The absence of dung fungal spores is therefore less informative than their presence. Dung fungal spores likely enter the sediment record through a different pathway from wind-borne pollen and thus dung fungal abundance is better expressed as influx rates than as percentage of total pollen. Landscape openness, vegetation type and site wetness do not distort the impact of utilisation levels on dung fungal spore representation. However, dung fungal spore influx varies markedly between seasons and years. Spores travel, leading to a background level of spore deposition across the landscape, and at times a depletion of spores, especially under wet weather conditions. Animal behaviour, as well as husbandry practices, can lead to the accumulation of dung, and thus fungal spores, in specific locations on the landscape that do not directly reflect grazing pressure.

A 1200-year history of environmental changes in Bay Jimmy area, coastal Louisiana, USA

Paleoecological studies from the northern Gulf of Mexico (GOM) have mostly aimed at understanding long-term paleoenvironmental changes. Only a few studies have been performed in the southern United States focusing on paleoenvironmental changes during the common era. This study investigated paleoenvironmental changes in coastal Louisiana over the past 1200 years by utilizing proxy data, including loss-on-ignition (LOI) and pollen from a sediment core collected from a wetland in Bay Jimmy. The results indicate that the marsh in the study area was formed at ca. AD 1090 and has been primarily shaped by prevailing climatic conditions, including rare extreme events. At least four major hurricanes impacted the site over the 1200 years, including two that made landfall in recent times. The findings show that coastal Louisiana was warm and dry during the ‘Medieval Warm Period’ (ca. AD 950–1250). The environment after AD 1090 contained scattered Pinus and Juglans vegetation communities that were later succeeded by a closed forest that included Quercus and Morus. Red mangrove ( Rhizophora) was established in the vicinity of Bay Jimmy until shortly after cal AD 1450 and 1640. The pollen record indicates that the ‘Little Ice Age’ period (AD 1550–1850) was cold and dry, characterized by a more open vegetation community. There is evidence of forest disturbance that is marked by a rise in Ambrosia pollen in the 1700s, coinciding with the time of European settlement in North America. The presence of Ambrosia and Cheno/Am pollen throughout the record suggests that anthropogenic influence has been part of the fabric of the southern Louisiana landscapes throughout the 1200 years.

Late Pleistocene meso-megamammals from Anagé, Bahia, Brazil: Taxonomy and isotopic paleoecology (δ13C)

The fossils of Pleistocene megafauna are commonly found in tanks and cave deposits in the State of Bahia, northeastern Brazil. In general, studies on these materials have focused mainly on taxonomic aspects, but more recently, there has been an increase in paleoecological studies based on stable isotopes. The present paper describes fossils recovered from a tank deposit in Lagoa de Pedra (Anagé municipality, Bahia State). The material was identified as: Eremotherium laurillardi, Panochthus sp., Holmesina paulacoutoi, Palaeolama major, Notiomastodon platensis, and Toxodontinae indet. Stable isotope analyses were performed in order to estimate their diet and the paleoenvironment in which these taxa lived. The results indicate the occurrence of two guilds: grazers (Panochthus sp.) and mixed-feeders (H. paulacoutoi, N. platensis and E. laurillardi). These animals lived in a more open environment where N. platensis possibly had a major role in the community organization.

Pleistocene vertebrate tracksites on the Cape south coast of South Africa and their potential palaeoecological implications

Body fossil remains usually provide the main palaeontological resource for palaeoecological studies. Ichnology has the capacity to independently complement such data. Fossil tracksites provide a direct record of animals whose tracks have been preserved, and with regard to the Palaeo-Agulhas Plain they have direct relevance in considering palaeoecology. While biases may be present in ichnological data, they are different from the biases inherent in traditional body fossil studies. A ground survey along a 350 km portion of the Cape south coast, between Arniston in the west and Robberg in the east, identified well over a hundred-and-thirty ichnofossil sites in Late Pleistocene coastal aeolianites and lithified foreshore deposits. Some of these tracks were made by extinct species or subspecies. In other cases these tracksites demonstrate spatial range extensions of extant species, when compared with data available from body fossils or historical records. These sites include the largest and best preserved archive of Late Pleistocene hominin tracks thus far described. The tracksites occur on the margin of the Palaeo-Agulhas Plain, which may allow for palaeoenvironmental conclusions to be drawn regarding Late Pleistocene conditions on this extinct landscape. We summarize the most important sites, discuss the limitations and challenges of ichnological studies, and provide perspectives on future work.