Woodland Expansion Research Articles

The nature and timing of landscape change at Cerro Benítez, Última Esperanza, southern Patagonia (52°S): New insights into the history of megafaunal extinctions and human occupation

A new Late glacial – Holocene palaeoenvironmental record from Cerro Benítez (51°33′S 72°35′W), Seno Última Esperanza, is presented. A pollen and spore record, from a closed basin mire, provides insight into the dramatic landscape changes spanning the past ~16,000 years. AMS radiocarbon dating, supplemented by the application of tephrochronology, provides robust age constraint. Our record of landscape change is set alongside a summary of the archaeofaunal records from the suite of caves and rock shelters that surround Cerro Benítez. Our record begins c. 16.3 ka, sometime after glacier retreat from the area, and describes a treeless landscape favoured by large grazing animals. At c. 14.9 ka, southern beech trees began to migrate into the area, but the landscape remained open with sufficient open ground for grazers. At c. 12.0 ka there was a dramatic expansion of woodland, but the decline of large mammals appears to have started some ~700 years earlier and is coincident with the arrival of hunter-gatherers in the area c. 12.7 ka. However, there is no archaeological evidence for human induced mass killing events, and it is likely that Cerro Benítez was a marginal resource area for early hunters that fell in and out of favour as the landscape changed during the Holocene; initially, less favourable during the early Holocene dry period (c. 11.0–8.0 ka) and more in favour during the mid-to late Holocene, although increasingly supplemented by more distant (~5–10 km) materials, including marine resources from the Golfo Almirante Montt.

LandTrendr smoothed spectral profiles enhance woody encroachment monitoring

Secondary succession (SS) is one of the main consequences of the abandonment of agricultural and forestry practices in rural areas, causing -among other processes- woody encroachment on former pastures and croplands. In this study we model and monitor the spatial evolution of SS over semi-natural grassland communities in the mountain range of the Pyrenees in Spain, during the last 36 years (1984-2019). Independent variables for ‘annual-based’ and ‘period-based’ modeling were drawn from a suite of Surface Reflectance Landsat images, LandTrendr (LT)-algorithm-adjusted images and LT outputs. Support vector machine (SVM) classifiers were trained and tested using all possible variable combinations of all the aforementioned datasets. The best modeling strategy involved yearly time series of LT-adjusted Tasseled Cap Brightness (TCB) and Wetness (TCW) axes as predictors, attaining a F1-score of 0.85, a Matthew Correlation Coefficient (MCC) of 0.67 and an AUC 0.83. Woodlands encroached above 480,000 ha of grasslands and crops during the study period. A model using LT outputs for the whole period also denoted good performance (F1-score = 0.85, MCC = 0.75) and estimated a similar area of woodland expansion (~509,000 ha), but this ‘period’ approach was unable to provide temporal information on the year or the encroachment dynamics. Our results suggest an overall proportion of 66% for the Pyrenees being affected by SS, with higher intensity in the west-central part, decreasing towards the eastern end.

Challenges of Brush Management Treatment Effectiveness in Southern Great Plains, United States

Woodland expansion is a global challenge documented under varying degrees of disturbance, climate, and land ownership patterns. In North American rangelands, mechanical and chemical brush management practices and prescribed fire are frequently promoted by agencies and used by private landowners to reduce woody plant cover. We assess the distribution of agency-supported cost sharing of brush management (2000−2017) in the southern Great Plains, United States, and evaluate the longevity of treatment application. We test the general expectation that the current brush management paradigm in the southern Great Plains reduces woody plants and conserves rangeland resources at broad scales. This study represents the most comprehensive assessment of treatment longevity following brush management in the southern Great Plains by linking confidential private lands management data to a national inventory program (US Department of Agriculture Natural Resources Conservation Service National Resources Inventory). We observed regional differences in the types of brush management techniques used in cost-sharing programs throughout the study area. Mechanical brush management was the most common practice cost shared in Texas, while a mixture of mechanical and chemical application was most common in Oklahoma. Prescribed fire was most common in Kansas with some areas receiving chemical treatment. Our analysis showed brush management, as implemented, did not reduce tree cover long term and minimally reduced shrub cover. Evidence to support the current brush management paradigm only existed at local site-level scales of analysis (40- to 50-acre area), but treatment effectiveness was short-lived. At regional scales, observed changes in woody plant cover showed little to no overall net reduction from 2000 to 2017. These findings bring into question the philosophy of the current brush management paradigm, its implementation as the default rangeland conservation practice, and its prioritization over alternative practices that prevent new woody plant establishment and enhance resilience of rangelands in the southern Great Plains region.

The carbon sequestration potential of Scottish native woodland

Woodland creation sequesters carbon and contributes to climate change mitigation. Most previous assessments of the carbon sequestration of new UK woodlands have focused on tree planting, little is known about the scale of the potential contribution from natural regeneration. We used a Potential for Native Woodland Model to make the first estimate of carbon sequestration by large-scale native woodland expansion through natural regeneration in Scotland. We estimate native woodland could expand to cover an additional 3.9 million hectares of the Scottish uplands removing an average of 6.96 million tons of CO2 per year. This represents 35%–45% of the carbon removal target for UK woodlands that has been suggested by the UK Committee on Climate Change. Expanding woodlands to just 10% of this potential would double existing native woodland and could provide a multitude of benefits, including carbon removal equivalent to approximately 4% of this target. The next few decades are critical in terms of climate change mitigation, therefore further work is now required to improve these estimates and better constrain this potentially large contribution.

Woodland Expansion in Upland National Parks: An Analysis of Stakeholder Views and Understanding in the Dartmoor National Park, UK

Woodland expansion on a significant scale is widely seen to be critical if governments are to achieve their net zero greenhouse gas ambitions. The United Kingdom government is committed to expanding tree cover from 13% to at least 17% in order to achieve net zero by 2050. With much lowland area under agricultural production, woodland expansion may be directed to upland areas, many of which are national parks under some degree of conservation jurisdiction. This may prove to be controversial, requiring full engagement with the interests of those individuals with a stake in their protection and management. In this paper, we explore how a range of stakeholders view the prospect of woodland expansion in Dartmoor National Park in southwest England, UK. Fifteen stakeholders—a mix of key informants and farmers—were shown different woodland expansion scenarios in map form and consulted using semi-structured interviews. The findings suggest widespread enthusiasm for woodland expansion, but with significant differences in terms of the scale and approach. Stakeholders raised topics of biodiversity gain, climate change mitigation, environmental benefits, cultural ecosystem gain, and forest crop benefits. Caution was expressed regarding target setting, the place of woodland expansion in the national debate, and the potential for harm from inappropriate new planting. The constraints identified were land tenure patterns, notably tenancy insecurity and ‘common land’ challenges, historical farming policy and culture, landscape objectives, and future policy design.

Microclimates hold the key to spatial forest planning under climate change: Cyanolichens in temperate rainforest.

There is deepening interest in how microclimatic refugia can reduce species threat, if suitable climatic conditions are maintained locally, despite global climate change. Microclimates are a particularly important consideration in topographically heterogeneous landscapes, while in some habitats, such as forests and woodlands, microclimates are also extremely labile and affected by management practices that could consequently be used to offset climate change impact. This study explored a conservation priority guild-cyanolichen epiphytes in temperate rainforest-quantifying the niche response to macroclimate, and landscape or woodland stand structures that determine the microclimate. Based on epiphyte survey in a core region of European temperate rainforest (western Scotland), a 'random forest' machine-learning model confirmed a strong cyanolichen response to summer dryness, as well as the effects of distance to running water, topographic heatload and tree species identity, which modify the local moisture regime and/or lichen growth rates. By quantifying this response to macroclimate, landscape and stand structures, it was possible to estimate an extent to which woodland may be expanded in the future, to offset a negative effect of increasing summer dryness projected through to the 2080s. Using current policy as a yardstick, sufficient woodland expansion could be delivered relatively quickly for median impacted sites, but with times to woodland delivery extending over 10, 20 and 25years for sites at the 75th, 90th and 95th percentiles of cyanolichen decline. Furthermore, the extent of new woodland required, and delivery times, increase almost threefold on average, as new woodland becomes distributed over wider riparian zones. These contrasting implications emphasize an urgent need for afforestation that achieves targeted spatial planning responsive to microclimates as refugia.

Holocene heathland development in temperate oceanic Southern Hemisphere: Key drivers in a global context

AbstractAimUnderstanding long‐term heathland development is key in mitigating their current attrition globally. However, such knowledge is limited in Australia and the wider Southern Hemisphere. We aim to identify potential climatic and environmental drivers of Holocene heathland development in temperate‐oceanic Australia (Bass Strait), and also assess the applicability of Iversen's conceptual model of interglacial vegetation development to the area.LocationBass Strait, southeast Australia.TaxonMonotoca, Epacris, Sprengelia and Restionaceae.MethodsWe used multiple sedimentary pollen and charcoal records from truwana/Cape Barren Island (CBI) in Bass Strait to reconstruct vegetation and fire history. We also used rarefaction analysis on pollen records to estimate floristic richness for all sites, and magnetic susceptibility and organic content were derived for two of the four sites as proxies for local sedimentary changes. Reconstructed vegetation and fire histories were then compared to independent records of climate and sea‐level change in temperate Australia, using a Detrended Correspondence Analysis ordination, to identify major drivers of heathland development.ResultsMajor heathland expansion occurred on truwana/CBI between the early and mid‐Holocene in response to sea‐level rise, high effective precipitation, reduced seasonality and increased Indigenous burning. Increasing seasonality, low effective precipitation, El Niño‐Southern Oscillation intensification, stable sea level, and decreased fire activity drove the expansion of scrub and woodland at the expense of heathland in the late Holocene. The overall vegetation development on truwana/CBI fits poorly with the classic Iversen conceptual model of interglacial vegetation development in the Northern Hemisphere, due to the significant role of interglacial sea‐level rise on truwana/CBI. Therefore, a modified model, which takes into account the role of sea‐level change, is proposed for Southern Hemisphere‐temperate‐oceanic settings.Main conclusionsHeathland developments in both hemispheres reflect some level of homogeneity, considering the roles of increased Indigenous burning and reduced seasonality in both hemispheres. Frequent, controlled burning strategies are recommended to maintain heathland on truwana/CBI.

The Impact of Land Use Change on Water-Related Ecosystem Services in the Bashang Area of Hebei Province, China

Land use change is an important scientific issue recognized for its potential to alter ecosystem services (ESs), especially water-related ecosystem services (WRESs). Using the integrated valuation of ecosystem services and trade-offs (InVEST) model, this study quantified and mapped spatiotemporal variations in land use and corresponding WRESs in the Bashang area of Hebei Province, China (BAHP) to investigate how land use change impacted WRESs by means of scenario analysis, especially, in which a new evaluation indicator, average ecology effect (AEE) was proposed and well applied. The results indicated that woodland expansion (+602.61 km2) and grassland shrinkage (−500.57 km2) dominated the land use change in the BAHP in 2000–2018, which altered local WRESs, including the moderate declines in water purification and water yield, as well as a significant enhancement in soil conservation. In scenario analysis, compared to baseline levels, riparian woodland buffer and planting trees scenarios slightly decreased water yield but strengthened water purification and soil conservation; reclaiming wasteland and integrated development scenarios significantly enhanced soil conservation but lowered water yield and water purification; fertilizer reduction scenario effectively mitigated water deterioration. According to AEE, the riparian woodland buffer (RWB) scenario performed greater than the planting trees (PT) scenario on variations of WRESs per unit area, which differed completely from the results based on total variations. Overall, a multiple-scale indicator for a comprehensive evaluation of ESs should receive more attention.

The Return of Wooded Landscapes in Wales: An Exploration of Possible Post-Brexit Futures

Changes in agricultural policy may have a rapid impact, even on landscapes which have taken millennia to form. Here we explore the potential impact of the UK leaving the EU as a catalyst for profound changes in the pastoral landscapes of Wales. Impending change of the trading regime governing agricultural produce, concurrent with public pressure to use agricultural subsidies for environmental goals, may lead to unforeseen consequences for the Welsh natural environment. We employ a combination of change demand modelling and a ‘story and simulation approach’ to project the effect of five hypothetical plausible scenarios on land use and land use change in Wales by 2030. We show that the most extreme trade scenario would result in a significant expansion of broadleaf woodland across much of Wales. By contrast, the ‘green futures’ scenario introduced to supersede the Common Agricultural Policy, results in significant expansion of woodland but not at the level seen with the more extreme trade scenarios.

Plant functional groups and species contribute to ecological resilience a decade after woodland expansion treatments

AbstractWoody plant expansions are altering ecosystem structure and function, as well as fire regimes, around the globe. Tree‐reduction treatments are widely implemented in expanding woodlands to reduce fuel loads, increase ecological resilience, and improve habitat, but few studies have measured treatment outcomes over long timescales or large geographic areas. The Sagebrush Treatment Evaluation Project (SageSTEP) evaluated the ecological effects of prescribed fire and cut‐and‐leave treatments in sagebrush communities experiencing tree expansion in North American cold desert shrublands. We used 10 yr of data from the SageSTEP network to test how treatments interacted with pre‐treatment tree dominance, soil climate, and time since treatment to affect plant functional groups and dominant species. Non‐sprouting shrub (Artemisia spp.), sprouting shrub, perennial graminoid, and annual grass responses depended on tree dominance and soil climate, and responses were related to the dominant species' life‐history traits. Sites with warm and dry soils showed increased perennial graminoid but reduced Artemisia shrub cover across the tree dominance gradient after prescribed burning, while sites with cool and moist soils showed favorable post‐burn responses for both functional types, particularly at low to moderate tree dominance. Cut‐and‐leave treatments sustained or increased native perennial plant functional groups and experienced smaller increases in exotic annual plants in both soil climates across the tree dominance gradient. Both treatments reduced biocrust cover. Selecting appropriate tree‐reduction treatments to achieve desired long‐term outcomes requires consideration of dominant species, site environmental conditions, and the degree of woodland expansion. Careful selection of management treatments will reduce the likelihood of undesirable consequences to the ecosystem.

The Holocene paleoenvironmental history of Western Caucasus (Russia) reconstructed by multi-proxy analysis of the continuous sediment sequence from Lake Khuko

This paper presents new multi-proxy records of the Holocene environmental and climatic changes in the Western Caucasus revealed from a continuous sediment sequence from mountainous Lake Khuko (Caucasus State Natural Biospheric Reserve, 1744 m a.s.l.). Palaeoecological analyses of a sediment core for grain size, magnetic susceptibility, loss on ignition, and pollen allowed us to determine five principal climatic phases with several subphases since 10.5 ka BP. The age model is based on seven accelerator mass spectrometry 14C dates, supplemented by 210Pb data for the uppermost part of the sediment core. Warm periods (10.5–6.7, 6.7–5.5, 3.5–2.4, 0.8–0.5 ka BP) were characterized by high biological productivity in the lake as indicated by high organic matter content and expansion of forests, typical of modern low and middle mountain zones, as indicated by the increase in abundance of Quercus, Ulmus, Corylus, and Tilia in the pollen assemblages. Cold periods (5.5–3.5, 2.4–0.8, and 0.5 ka BP–present) are marked by a consistent decrease in organic matter content in lake deposits and possibly higher intensity of the catchment erosion. The changes in pollen assemblages (for instance peaks of Abies, Picea, and Pinus) suggested a potential elevational decline in the boundaries of vegetation belts and expansion of high-altitude woodlands. Abrupt changes in the lake ecosystem were identified between 4.2 and 3.5 ka cal BP marked by a short-term variation in sediment regime shown by variation in organic matter content, magnetic susceptibility values, and sediment grain size. This was probably caused by climatic fluctuations in the Western Caucasus region as a result of complex shifts in the ocean-atmosphere system during the 4.2 ka event. Overall, the first Holocene multi-proxy continuous lake sediment record provides new insights into the climate history in the Western Caucasus.

Vegetation change in southeastern Greece during the Late Pleistocene. The wood charcoal record from Klissoura Cave 1 (Peloponnese, Greece)

The late Pleistocene and early Holocene vegetation of southeastern Greece is coming to light through the study of well-preserved wood charcoal assemblages from cave sites in the Peloponnese dating from the Middle Palaeolithic to the Neolithic. New anthracological results from Klissoura Cave 1 in the Argolid are presented. These, alongside the recently published charcoal sequence from Franchthi Cave (Asouti et al., 2018) and preliminary anthracological results from Kephalari Cave are integrated in a synthetic discussion, which tracks changes in the vegetation from the late Pleistocene to the early Holocene. Specific markers of vegetation change are looked for in the anthracological record, i.e. Olea europaea, deciduous Quercus, Juniperus sp., Amygdalus, Maloideae. The charcoal sequence from Klissoura Cave 1 spans from 123 ka BP to 35 ka cal BP. The results show that, during the MIS 5e, thermophilous Olea/mesophilous deciduous Quercus woodlands prevailed in the area under the influence of warm and relatively humid conditions. Lower precipitation after MIS 5e and in the course of MIS 5 resulted in the expansion of thermophilous Olea woodlands under increasingly drier conditions. Open Amygdalus woodland expanded in the later part of MIS 5 in agreement with progressively drier and cooler conditions. Juniperus woodland prevailed at the beginning of MIS 3 while progressively warmer and more humid interstadial conditions favoured the expansion of mesophilous Quercus woodland. Drier conditions during the later part of MIS 3 would have resulted in changes in the composition of the mesophilous woodlands and another cycle of expansion of Amygdalus open vegetation. Changes in the vegetation during MIS 2 and the Lateglacial follow similar patterns according to complementary anthracological evidence from the Kephalari and Franchthi caves.

Change in Piñon-Juniper Woodland Cover Since Euro-American Settlement: Expansion Versus Contraction Associated with Soil Properties

Woodland and forest ecosystems across western North America have experienced increased density and expansion since the early 1900s, including in the widely distributed piñon-juniper vegetation type of the western United States. Fire suppression and grazing are often cited as the main drivers of these historic changes and have led to extensive tree-reduction treatments across the region. However, much of the scientific literature on piñon-juniper expansion dates back only to the early 1900s, which is generally half a century after Euro-American settlement. Yet US General Land Office (GLO) surveys provide valuable insight into the historical extent and density of woodland and forest ecosystems as surveyors would note where on the landscape they entered and exited woodlands or forests and provided qualitative estimates of relative tree density. This study uses these GLO surveys to establish piñon-juniper woodland extent in the late 19th century at the incipient stages of Euro-American settlement in southeastern Colorado and compares these data with 2017 aerial imagery of woodland cover. We found substantial amounts of woodland contraction, as well as expansion: ≈61% of historically dense woodland is now savanna or open (treeless), whereas ≈57% of historically open areas are now savannas or woodlands. The highest rates of expansion occurred on shallow, rocky soil types with low soil available water capacity, which support little herbaceous vegetation and were consequently less likely to be affected by fire suppression or grazing. Meanwhile, the significant contractions in woodland extent occurred on deeper, upland soils with higher soil available water capacity, which were likely where early settlement and tree cutting was most prevalent. Our results provide mixed support for the widespread assumption of woodland expansion since Euro-American settlement in southeast Colorado and suggest that the expansion that has occurred in our study area is unlikely a result of past grazing or fire suppression.

Understanding of Forest Cover Dynamics in Traditional Landscapes: Mapping Trajectories of Changes in Mountain Territories (1824–2016), on the Example of Jeleniogórska Basin, Poland

Though on a global scale, for ecological reasons, increased forest cover is universally regarded as positive, on a local scale, the reforestation of arable land may pose threats to cultural landscapes by removing characteristic landscape features. Particularly vulnerable are marginal rural areas, e.g., mountain regions, where most traditional land use systems have survived and which are subject to the most spectacular land use change. The purpose of this article is to draw attention to the issue of the management of forest cover in historical cultural landscapes in mountain territories in Poland within the context of widespread land use change in Eastern Europe. Land cover data were obtained from historical and contemporary aerial photographs, as well as topographic maps from five time points between 1824 and 2016. The study was conducted by means of spatio-temporal forest cover trajectory analysis (LCTA), transition and time–depth analysis, and land cover change calculations that were made by means of ArcGIS. Our research indicates that the rate of change has risen considerably in the last two decades, and the current share of forest cover is much bigger than that reflected in the official data. Eight principal forest cover trajectory types were identified. The biggest area is occupied by woodland of long-term stability. Another large group is constituted by forests created on the basis of arable land and grassland as a result of simple conversion at one point in time, mainly in the years 1824–1886 and 1939–1994. At the same time, a sizeable group is made up by areas that have been subject to unplanned cyclical or dynamic changes during various periods. A very important group is comprised new forests that were created in 1994–2016, predominantly as a result of natural succession, that are often not included in official land classifications. The constant expansion of woodlands has led to a shrinking of historical former coppice woodlands. This indicates that the current landscape management mechanisms in Poland are inadequate for protecting the cultural landscape. The barriers include the lack of intersectoral cooperation and the overlooking of the historical context of landscapes. The present situation calls not only for verification of the existing forest policy but also for increasing the role and engagement of local communities, as well as making comprehensive local development plans, all of which may be helped by the findings of our study and of similar research.

Migration, socioeconomic transformation, and land-use change in Mexico’s Mixteca Alta: Lessons for forest transition theory

The forest transition is a concept used to describe and explain the transition from a dwindling to an expanding forest area in a given region or country. Three main explanations of the forest transition have been developed. The first is the “economic development path to the forest transition”, which contends that economic development and new agricultural technologies trigger rural-urban migration and agricultural intensification, leading in turn to the abandonment of marginal farmland and eventually to a forest recovery. The second is the “forest scarcity path to the forest transition”, which argues that the scarcity of forests is a major factor that encourages commercial tree plantations, reforestations and the conservation of woodlands. A third explanation has been advanced in certain developing countries. This explanation, referred to in this paper as the “diversification of rural livelihoods path to the forest transition”, holds that rural households must adjust to outside forces, including globalization and neoliberal economic policies, and that those adjustments marginalize smallholder farming, allowing for the expansion of forests. This paper describes and explains the onset of a forest transition in the Mixteca Alta UNESCO Global Geopark, in the state of Oaxaca, Mexico. Based on qualitative fieldwork and the analysis of official statistics and land-use/cover maps, we contend that the three paths to the forest transition overlap in our study area. This implies a fuller and more complex explanation of the forest transition, which is crucial to understand the expansion of woodlands in other regions of Mexico and the developing world.

Challenges in delivering climate change policy through land use targets for afforestation and peatland restoration

Climate change policy for the land sector is challenged by complex biophysical and socioeconomic contexts. A target approach utilising land-use change indicators is often used to quantify and communicate progress, based upon assumed greenhouse gas emission (GHG) reductions. This paper investigated areal targets for woodland expansion and peatland restoration, both of which can deliver substantial carbon sequestration benefits, with uptake typically supported by grant incentives. A case study used empirical data to investigate realisation of such targets in Scotland referenced against ambitious policy commitments (net-zero emissions by 2045). Analysis of actual locations for recent afforestation and peatland restoration, referenced against biophysical data, showed that new woodland primarily occurred on land that was marginal for agriculture, usually on wetter uncultivated semi-natural land, often on organic soils. This acts to constrain net carbon gains. Both peatland restoration and new woodland show tendency to aggregate in specific zones or locations, regardless of biophysical opportunities, highlighting underlying socioeconomic factors. Differential patterns of uptake are also shown by grant applications across different land use groups. Socioeconomic factors act against more ubiquitous uptake of incentive schemes, especially for new woodland on improved agricultural land, which will constrain long-term decarbonisation objectives unless tackled directly. Investigation therefore shows that use of simple targets (e.g. trees planted) as headline progress indicators can be misleading, potentially contributing to policy failure and misuse of carbon offsets. A more spatially targeted approach is required to maximise GHG reductions relative to local contexts. Recommendations are made for improved measures that recognise spatial and temporal variability, as exemplified by certification schemes.

Quantifying Pinyon-Juniper Reduction within North America's Sagebrush Ecosystem

One of the primary conservation threats surrounding sagebrush (Artemisia spp.) ecosystems in the Intermountain West of the United States is the expansion and infilling of pinyon pine (Pinus edulis, P. monophylla) and juniper (Juniperus spp.) woodlands. Woodland expansion into sagebrush ecosystems has demonstrated impacts on sagebrush-associated flora and fauna, particularly the greater sage-grouse (Centrocercus urophasianus). These impacts have prompted government agencies, land managers, and landowners to ramp up pinyon-juniper removal efforts to maintain and restore sagebrush ecosystems. Accurately quantifying and analyzing management activities over time across broad spatial extents still poses a major challenge. Such information is vital to broad-scale planning and coordination of management efforts. To address this problem and aid future management planning, we applied a remote sensing change detection approach to map reductions in pinyon-juniper cover across the sage-grouse range and developed a method for rapidly updating maps of canopy cover. We found total conifer reduction over the past several yr (2011−2013 to 2015−2017) amounted to 1.6% of the area supporting tree cover within our study area, which is likely just keeping pace with estimates of expansion. Two-thirds of conifer reduction was attributed to active management (1.04% of the treed area) while wildfire accounted for one-third of all estimated conifer reduction in the region (0.56% of the treed area). Our results also illustrate the breadth of this management effort—crossing ownership, agency, and state boundaries. We conclude by identifying some key priorities that should be considered in future conifer management efforts based on our comprehensive assessment.

Palaeoenvironmental and chronological context of human occupations at El Cierro cave (Northern Spain) during the transition from the late Upper Pleistocene to the early Holocene

El Cierro Cave possesses one of the few sequences in SW Europe in which archaeological levels cover the transition from the late Pleistocene to the early Holocene. Information contributed by the palynological and anthracological studies indicates that this transition was marked by a steady expansion of broadleaf woodland and a reduction in herbaceous-shrub communities. Archaeofaunal studies reveal continuity in subsistence strategies throughout the sequence. This was based on specialisation in hunting red deer, fishing, and gathering molluscs, crustaceans and echinoderm species on rocky shores. The difference between the Azilian and Mesolithic occupations lies in the replacement of some marine invertebrate species and the decrease in limpet sizes. The abiotic evidence is characterised by a lithic assemblage with allochthonous flint types, which has been interpreted as continuity of the raw material procurement strategies inherited from the Magdalenian.

Climate change and biogeographic connectivity across the Brazilian cerrado

AbstractAimTo investigate cerrado responses to glacial–interglacial climate change and the potential for connective rain forest corridors between the Atlantic Coastal Forest and Amazonian rain forest.LocationThe crater lake of Serra Negra (18 °S, 46 °W) in Minas Gerais, Brazil.Taxon117 fossil pollen types, 22 non‐pollen palynomorphs were documented.MethodsWe recovered 7.82 m of sediment from the lake, and analysed fossil pollen at 62 depth intervals throughout the core. We derived a chronology based on radiocarbon dating with simple rate extrapolation to the base of the core.ResultsThe c. 90,000‐year fossil record showed a trend towards cooler climates at the Last Glacial Maximum (LGM), but interstadial warming coupled with reduced evaporative stress allowed the expansion of woodlands under cool, moist conditions. Cool‐adapted trees were most abundant between c. 67,000 and 48,000 years ago. A cool cerrado‐like environment marked full glacial conditions between c. 48,000 and 34,000 years ago. The peak of the LGM between c. 34,000 and 17,000 years ago is inferred to have been dry as no sediment accumulated in the system.Main conclusionsExpanded ranges of cold‐tolerant forest taxa led to establishment of a series of assemblages without modern analogue. A system characteristic of modern cerrado was rare in the history of this site. Multiple forest expansions were observed, each differing in composition. The periods of forest abundance at Serra Negra were not temporally aligned with forest expansion in the Atlantic Coastal Forest, and did not provide a continuous corridor of similar forest that connected the cerrado to the Atlantic Coastal Forest.

Predictive modelling in paleoenvironmental reconstruction: The micromammals of Manot Cave, Israel

This paper describes the micromammalian remains and paleoenvironment of the Upper Paleolithic sequence of Manot Cave (46-34 ka), southern Levant. Micromammal remains were identified from Ahmarian (46-42 ka), Levantine Aurignacian (38-34 ka) and post-Levantine Aurignacian (34-33 ka) layers. To identify taphonomic agents, molar digestion was modelled for seven local raptor species, and model predictions were compared with observed digestion scores in the Manot Cave material. Raptor species differed significantly in molar digestion patterns, allowing us to identify Tyto alba as the bone accumulator in the Ahmarian and Post-Levantine Aurignacian units. Data were insufficient for species-level identification of the taphonomic agent in the Levantine Aurignacian. Günther's voles (Microtus guentheri) were dominant, though woodland species (Apodemus spp., Sciurus anomalus and Dryomys nitedula) also occurred through the entire sequence. Manot Cave furnished the first fossil record of the Eurasian snow vole (Chionomys nivalis) in the southern Levant during the Late Pleistocene and its first secure record of the water vole (Arvicola terrestris) outside the Hula Valley. Records of other taxa (Acomys dimidiatus and D. nitedula) provide the earliest occurrence datum in the region. Using counts of both identified specimens and distinct elements (lower first molars) we modelled paleoenvironmental conditions through both Weighted Averaging Partial Least Squares regression and a qualitative analysis considering niche preferences of species. Model predictions indicate the unexpectedly pronounced dominance of open habitats compared to present conditions near the cave, though the occurrence and abundance of woodland species also indicate some woodland expansion relative to the preceding Middle Paleolithic period. Combining statistical models and species niche considerations we show that the time span between the Ahmarian, Levantine Aurignacian and post-Levantine Aurignacian was marked by a clear-cut climatic oscillation to cooler and likely wetter conditions.