F. Alayne Street-Perrott

• Swansea University

Tropical Montane Cloud Forests (TMCFs) form biodiverse communities that are characterized by frequent occurrence of low-level clouds from which they capture a substantial proportion of their precipitation — here referred to as occult precipitation. TMCFs provide important ecosystem services, in particular the supply of water to their wider surround...

Japanese knotweed, Fallopia japonica var. japonica, causes significant disruption to natural and managed habitats, and provides a model for the control of invasive rhizome-forming species. The socioeconomic impacts of the management of, or failure to manage, Japanese knotweed are enormous, annually costing hundreds of millions of pounds sterling (G...

The well characterized oxygen-isotopic fractionation during cellulose biosynthesis has been utilised by numerous studies of stable isotopes in fine-grained aquatic cellulose. We measured the δ¹³Ccellulose and δ¹⁸Ocellulose values of bulk cellulose and moss fragments from an ∼11.4ka-long core obtained from a shallow, productive, spring-fed, hardwate...

Significance Amazonian rainforests once thought to be pristine wildernesses are increasingly known to have been inhabited by large populations before European contact. How and to what extent these societies impacted their landscape through deforestation and forest management is still controversial, particularly in the vast interfluvial uplands that...

The gradient of air temperature with elevation (the temperature lapse rate) in the tropics is predicted to become less steep during the coming century as surface temperature rises, enhancing the threat of warming in high-mountain environments. However, the sensitivity of the lapse rate to climate change is uncertain because of poor constraints on h...

Transfer functions are now widely available to infer past environmental conditions from biotic assemblages. Existing transfer functions are based on species assemblages but an alternative is to characterize assemblages based on functional traits, characteristics of the organism which determine its fitness and performance. Here, we test the potentia...

Finding direct evidence for atmospheric circulation change in terrestrial records of Holocene climate variability remains a fundamental challenge. Here we present the first combined stable oxygen and hydrogen isotopic palaeorecord from a peatland core in Newfoundland, Canada. Sphagnum cellulose samples were isolated from a core from Nordan's Pond B...

Finding direct evidence for atmospheric circulation change in terrestrial records of Holocene climate variability remains a fundamental challenge. Here we present the first combined stable oxygen and hydrogen isotopic palaeorecord from a peatland core in Newfoundland, Canada. Sphagnum cellulose samples were isolated from a core from Nordan's Pond B...

Peat archives offer a diverse range of physical and chemical proxies from which it is possible to study past environmental and ecological changes. Direct numerical calibration and verification is difficult so process-based and mechanistic studies are therefore required to establish and quantify links between environmental changes and their associat...

The ombrotrophic peat bogs of Tierra del Fuego are located within the southern westerly wind belt (SWWB), which dominates climate variability in this region. We have reconstructed late-Holocene water-table depths from three peat bogs and aimed to relate these records to shifts in regional climate. Water-table depths were quantified by the analysis...

On Quaternary time scales, the global biogeochemical cycle of silicon is interlocked with the carbon cycle through biotic enhancement of silicate weathering and uptake of dissolved silica by vascular plants and aquatic microalgae (notably diatoms, for which Si is an essential nutrient). Large tropical river systems dominate the export of Si from th...

A technological development is described through which the stable carbon-, oxygen-, and nonexchangeable hydrogen-isotopic ratios (δ 13 C, δ 18 O, δ 2 H) are determined on a single carbohydrate (cellulose) sample with precision equivalent to conventional techniques (δ 13 C 0.15‰, δ 18 O 0.30‰, δ 2 H 3.0‰). This triple-isotope approach offers signifi...

Various environmental factors, including atmospheric CO2 (pCO(2)), regional climate, and fire, have been invoked as primary drivers of long-term variation in C-4 grass abundance. Evaluating these hypotheses has been difficult because available paleorecords often lack information on past C-4 grass abundance or potential environmental drivers. We ana...

We reconstructed aeolian dust accumulation during the Holocene from two radiocarbon-dated lake-sediment sequences from the Manga Grasslands in northeastern Nigeria in order to investigate long-term changes in the Harmattan dust system over West Africa and evaluate their possible causes. Flux values were low in the Early Holocene, decreasing further...

There is a relative paucity of palaeoclimatic archives in South America relative to many other regions of the world. This paucity must be addressed in order to validate climate models and improve our understanding of the global climate system. The southern westerlies represent an important component of climatic variability in the region and, in tur...

Diatom, geochemical and isotopic data provide a record of environmental change in Laguna La Gaiba, lowland Bolivia, over the last ca. 25 000 years. High-resolution diatom analysis around the last glacial–interglacial transition provides new insights into this period of change. The full and late glacial lake was generally quite shallow, but with evi...

Testate amoebae have been extensively used as proxies for environmental change and palaeoclimate reconstructions in European and North American peatlands. The presence of these micro-organisms near the peat surface is generally significantly linked to the local water table depth (WTD) and therefore preservation of the amoeba shells downcore allows...

Persistent cyclical patterns of centennial- to millennial-scale changes in key climate drivers, such as North Atlantic Deep Water formation and the Atlantic Meridional Overturning Circulation, have frequently been identified in Holocene palaeorecords of the mid- and eastern-Atlantic region. Given its proximity to the major discharge routes of the L...

Historical charcoal-production sites (Meilers) are characterised by thick charcoal-rich soil horizons. A traditional source of archaeological, anthracological and palaeoecological data, the potential role of Meilers in soil science and carbon (C) sequestration is often overlooked. Charcoal, the product of incomplete combustion of biomass, is C-rich...

The interpretation of Neotropical fossil phytolith assemblages for palaeoenvironmental and archaeological reconstructions relies on the development of appropriate modern analogues. We analyzed modern phytolith assemblages from the soils of ten distinctive tropical vegetation communities in eastern lowland Bolivia, ranging from terra firme humid eve...

Biochar, the carbon(C)-rich product of pyrolysis or incomplete combustion of biomass, has been suggested as one foundation for a low-C economy, through its potential contributions to C sequestration in soils, fertilizer substitution and optimization, and soil amendment. Questions remain, however, regarding biochar longevity and behaviour in the soi...

Seasonal variations in hydrology and Si cycling in the Nile Basin were investigated using stable-isotope (H, O, and Si) compositions and dissolved Si (DSi) concentrations of surface waters, as a basis for interpreting lacustrine diatom sequences. δ18O ranged from −4.7 to +8.0‰ in the wet season and +0.6 to +8.8‰ in the dry season (through 2009–2011...

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are a novel proxy for mean annual air temperature (MAAT) and have the potential to be broadly applicable to climate reconstruction using lacustrine sediments. Several calibrations have been put forth relating brGDGT distributions to MAAT using a variety of linear regressions, including the me...

We present the first continuous paleolimnological reconstruction from the North Island of New Zealand (37°S) that spans the last 48.2 cal kyr. A tephra- and radiocarbon-based chronology was developed to infer the timing of marked paleolimnological changes in Lake Pupuke, Auckland, New Zealand, identified using sedimentology, magnetic susceptibility...

A continuous, 1,420-cm sediment record from Lake Pupuke, Auckland, New Zealand (37°S) was analysed for diatom taxonomy, concentration and flux. A New Zealand freshwater diatom transfer function was applied to infer past pH, electrical conductivity, dissolved reactive phosphorus and chlorophyll a. A precise, mixed-effect regression model of age vers...

Ombrotrophic raised peatlands provide an ideal archive for integrating late Holocene records of variations in hydroclimate and the estimated stable isotope composition of precipitation with recent instrumental measurements. Modern measurements of mean monthly surface air temperature, precipitation, and �D and �18O-values in precipitation from the l...

The debate about biochar systems within the scientific and environmental communities has focussed not only on the potential contribution of biochar to carbon sequestration and offsetting fossil carbon via sustainable bioenergy production, but also on its value as a fertilizer and soil-amendment product. Despite detailed studies of historical black...

An abrupt cold event ca. 8200 cal. yr BP, is believed to have been caused by the catastrophic release of ice-dammed meltwater from Lake Agassiz and associated disruption of the Atlantic Meridional Overturning Circulation (AMOC). Previous reviews have highlighted both the “ideal” nature of the 8200 yr event as a target for numerical model validation...

PRECIP (Palaeo-REconstruction of ocean-atmosphere Coupling In Peat) is a multi-proxy project examining the influences of Gulf Stream and Labrador Current variations on Holocene raised bogs along the Atlantic seaboard of North America. The project aims to reconstruct the influences of such climate drivers at multi-decadal timescales, thus enabling t...

Stable isotope analysis of sedimentary carbon in lakes can help reveal changes in terrestrial and aquatic carbon cycles. A method based on a single, photosynthetic organism, where host effects are minimised, should offer more precision than carbon isotope studies of bulk lake sediments. Here we report the development of a systematic method for use...

Ombrotrophic peat bogs are an important ecosystem containing large amounts of palaeohydrological information as they derive all of their moisture inputs from the atmosphere. By exploiting this relationship to the atmosphere, peat bogs have long become an established source of information about past climate change. Past changes in atmospheric moistu...

Dataset represented in figure 3, comprising a breakdown of 100 years cumulative net avoided greenhouse gas emissions by feedstock and cause.

Supplementary Note, Supplementary Methods, Supplementary Figures S1–S12, Supplementary Tables S1–S15 and Supplementary References

Production of biochar (the carbon (C)-rich solid formed by pyrolysis of biomass) and its storage in soils have been suggested as a means of abating climate change by sequestering carbon, while simultaneously providing energy and increasing crop yields. Substantial uncertainties exist, however, regarding the impact, capacity and sustainability of bi...

Stable isotope analyses of Sphagnum alpha-cellulose, precipitation and bog water from three sites across northwestern Europe (Raheenmore, Ireland, Walton Moss, northern England and Dosenmoor, northern Germany) over a total period of 26 months were used to investigate the nature of the climatic signal recorded by Sphagnum moss. The δ18O values of mo...

High-resolution Late Quaternary paleoclimate archives are preserved in the lake sediment records contained in several maar craters from the Auckland region in northern New Zealand. Tephrochronology, AMS 14C and Ar/Ar -based chronostratigraphies were developed with several lakes containing laminated sediment records spanning much of the last glacial...

An altitudinal survey of grasses and sedges was conducted on the Sirimon and Chogoria tracks on Mount Kenya to supplement previous surveys restricted to the Timau track. Thirty seven grasses and twenty three sedges were recorded and stable carbon isotope analysis was used to identify the photosynthetic pathway (C3 or C4) used by these species. The...

On geological time-scales (≥106 years), the global geochemical cycles of carbon and silicon are coupled by the drawdown of atmospheric CO2 through chemical weathering of Ca- and Mg-silicate minerals in continental rocks. Rivers transport the soluble products of weathering (cations, alkalinity and silicic acid) to the oceans, where they are utilized...

Previous studies have demonstrated long-term changes in effective moisture in sub-Saharan Africa. Here, we reconstruct Holocene environments using a ∼7 m lake-sediment sequence recovered from the northeastern Nigerian Sahel and attempt to distinguish basin-specific changes from regional climatic variations. The sequence was analysed for sedimentolo...

Silicon is an essential nutrient for marine diatoms, which dominate the export of organic carbon to the deep ocean. Despite the dominance of the oceanic Si budget by fluvial inputs and the role of the land biosphere in controlling Si losses from rocks and soils to rivers, few studies have considered how continental biogeochemical Si fluxes varied o...

This special issue of the Journal of Quaternary Science comprises a selection of papers from the third meeting of a series on ‘ISOtopes in PALaeoenvironmental reconstruction’ (ISOPAL), themed around Isotopes and Biogenic silica (IBiS). The meeting was held at the British Geological Survey (Nottingham, UK) in April 2007, and consisted of a series of...

Tropical Africa is at the geographical heart of the PEP III transect and forms part of the heat engine which drives the meridional circulation of the atmosphere. The tropics are therefore central to studies of climate change not only in the equatorial belt but also in sub-tropical regions (Yin and Battisti 2001), and may even lead some high latitud...

Aim: This study aims to separate regional and local controls on Holocene vegetation development and examine how well pollen records reflect climate change in a semi-arid region. The relative importance of climate and human activity as agents of vegetation change in the Sahel during the late-Holocene is also considered. Location: Jikariya Lake, an...

The degree to which different lakes within a landscape respond coherently (in unison) to external drivers such as climate change and soil development is uncertain. Presentation of multi-proxy, geochemical and palaeoecological data from individual lakes in the form of fluxes minimizes distortions resulting from variable sedimentation rates and chang...

Kiluli Swamp is an extensive valley swamp near the lower limit of the montane forest on the eastern slopes of Mount Kenya, East Africa. The swamp is fed by a small spring on the northeastern margin, and the water table lies a few centimetres below the surface. The swamp's sediments modify water chemistry: the Na-Mg-HCO3 water-type at the input chan...

The PEP III Europe-Africa transect extends from the arctic fringes of NW Eurasia to South Africa. It encompasses the presently temperate sector of mid-latitude Europe, the Mediterranean region, the arid and semi-arid lands of the Sahara, Sahel and the Arabian Peninsula, and the inter-tropical belt of Africa. The palaeoenvironmental evidence availab...

The δ13C signature of sedimentary organic matter acts as a tracer for past changes in the terrestrial and aquatic carbon cycles. Compound-specific δ13C analysis enables these two signals to be disentangled. We compare the molecular-isotopic records from a transect of five lakes between 1820 and 4595 m a.s.l. on Mt. Kenya, East Africa, spanning the...

Woody, subalpine shrubs and grasses currently surround Lake Rutundu, Mount Kenya. Multiple proxies, including carbon isotopes, pollen and grass cuticles, from a 755-cm-long core were used to reconstruct the vegetation over the past 38 300 calendar years. Stable carbon-isotope ratios of total organic carbon and terrestrial biomarkers from the lake s...

Stable-isotope measurements and modern aquatic chemistry are used to aid the reconstruction of past hydrological changes recorded in a 126 ka-long sediment core from Lake Kopais, Greece. This is the most southeasterly European site with a long Late Quaternary sequence. Although the lake has been artificially drained, calcareous sediments from the c...

Palaeoecological reconstructions based on a single proxy are limited, but by combining pollen, biogeochemistry and grass cuticle analysis, ecosystem structure and function can be better understood. Lake Rutundu is a small, subalpine lake on the northeast flank of Mt Kenya. During the last glacial, pollen evidence suggests a shrub grassland dominate...

Although C4 plant expansions have been recognized in the late Miocene, identification of the underlying causes is complicated by the uncertainties associated with estimates of ancient precipitation, temperature, and partial pressure of atmospheric carbon dioxide (P co 2). Here we report the carbon isotopic compositions of leaf waxn-alkanes in lake...

Oxygen isotopes are sensitive tracers of climate change in tropical regions. Abrupt shifts of up to 18 per mil in the oxygen isotope ratio of diatom silica have been found in a 14,000-year record from two alpine lakes on Mt. Kenya. Interpretation of tropical-montane isotope records is controversial, especially concerning the relative roles of preci...

Multi-proxy evidence from Sacred Lake on Mount Kenya, including pollen and compound-specific carbon isotope data, indicates grassland expansion at the Last Glacial Maximum (LGM, circa 18,000 14C years BP), but lacks the taxonomic resolution with which to derive ecological inferences about past grasslands. Analysis of grass cuticles preserved in Eas...

In this paper we examine the long-term temporal characteristics of palaeomonsoon dynamics in equatorial Africa from a continuous lacustrine sequence retrieved from Sacred Lake, Mount Kenya (0°03′N, 37°32′E, 2350 m a.s.l.), covering the last interglacial–glacial transition to the present. The trends in mineral magnetics and stable carbon isotopes ar...

In this paper, a sequence of five Late Quaternary tephras occurring as discrete, well-preserved horizons in lake sediments on the northeastern flank of Mount Kenya are characterised and their ages determined by a combination of high-resolution indirect radiocarbon dating and direct dating. The grain size characteristics suggest that the tephras are...

A high-resolution, multiproxy palaeolimnological record from the Manga Grasslands, northeastern Nigeria, spanning the last 5500 calendar years, reveals the episodic deterioration in Sahelian climate as significant biogeophysical thresholds were crossed. Desert-dust deposition began to increase similar to 4700 cal. BP. Rainfall during the summer-mon...

Sediments from Sacred Lake and Lake Nkunga on the northeastern flank of Mount Kenya have a sequential palaeoclimatic and palaeoenvironmental record covering most of the Late Quaternary period: from ca 115 to O ka. Most of the Late Quaternary period (110 to 14 ka - glacial period) was characterised by terrestrial C4 vegetation types (grassland) at h...

Molecular stratigraphic analyses, including lipid distributions and compound-specific δ13C measurements, have been performed at 15 levels in a sediment core from Sacred Lake, Mt. Kenya, a high-altitude (2350 m a.s.l.) freshwater lake with a record extending from the last glacial (>40,000 cal. yr BP) through the present interglacial. Terrestrial and...

A multidisciplinary study of lake sediments from Bal Lake, a small saline lake in the Sahel zone of northeastern Nigeria, provides evidence for changing precipitation/evaporation ratios over the last 1000 cal. years. Climatic and environmental changes over this period have been reconstructed using evidence from ostracod faunal assemblages and shell...

This paper presents a synthesis of results from investigations into palaeolimnology and dune chronology in the Manga Grasslands and adjacent areas of NE Nigeria, in order to reconstruct the evolution of this semi-arid landscape since the late glacial. A marked wet phase gave way to a Fall in lake levels during the late glacial. Dune emplacement was...

The ostracod record from Kajemarum Oasis in the Sahel zone of Northeastern Nigeria covers the last c. 4000 cal. years of a 5500 cal. year lake-sediment sequence. The first appearance of ostracods, around 4000 cal. yr BP, reflects the switch from a very dilute lake during the mid-Holocene, to slightly oligosaline conditions that favoured the occurre...

Carbon-isotope values of bulk organic matter from high-altitude lakes on Mount Kenya and Mount Elgon, East Africa, were 10 to 14 per mil higher during glacial times than they are today. Compound-specific isotope analyses of leaf waxes and algal biomarkers show that organisms possessing CO2-concentrating mechanisms, including C4 grasses and freshwat...

Abrupt climatic changes : evidence from closed lakes in the montane rain forests of East Africa. Freshwater algae and organisms possessing CO2-concentrating mechanisms are responsible for the increase of the Carbon-isotope value of bulk organic matter during glacial time. Relation between Carbon limitation and the distribution of forest on the trop...

Lakes in the limestone region of Jamaica exhibit a range of chemical characteristics that reflect varying inputs from precipitation, surface runoff and groundwater, together with the subsequent evolution of the water within the limnic environment. Detailed spatial and temporal sampling was conducted on one lake, Wallywash Great Pond. Chemical data,...

There has long been speculation as to the relationship between climate, humans and the environment. Until recently, however, it has proved difficult to establish the degree to which these factors are interlinked. Here we draw on evidence that has recently emerged from a series of investigations in central México to evaluate the long-term human impa...

The levels and areas of lakes, particularly closed lakes (those without outlet) are known to be sensitive indicators of changes in climate, and so in principle they can play a role in monitoring current and future climatic changes. In this paper we derive solutions to the water balance equation giving the response of the level and area of closed la...

Wallywash Great Pond (17 57 N, 77 48 W, 7 m a.s.l.) is the largest perennial lake in Jamaica. It occupies a fault trough within the karstic White Limestone. The Great Pond is a hardwater lake with a pH of 8.2–8.6 and an alkalinity of 3.6–3.9 meq 1–1. Its chemistry is strongly influenced by the spring discharge from the limestone. The lake water is...