Woodland Ecosystems Research Articles

From Mesolithic hunters to Iron Age herders: a unique record of woodland use from eastern central Europe (Czech Republic)

In a continuous, perfectly stratified sedimentary sequence which was discovered under a large sandstone overhang in northern Bohemia, Czech Republic, we analysed multiple biological remains, archaeological features and artefacts. This multi-proxy record has allowed us to examine the interactions between woodland and humans in a permanently wooded environment throughout almost the entire Holocene. We paid most attention to massive finds of dung pellets from sheep, goats or pigs and bedding layers which show that the site was used as a pen and shelter for livestock which grazed in the woods. Our results imply that such practices have occurred since the Neolithic, but the most robust evidence of these is for the Iron Age and early Middle Ages. Detailed analyses of the dung indicate woodland grazing and foddering with branches, acorns, beechnuts and crop processing remains. In addition, the wide palaeoenvironmental range of this detailed investigation provides evidence of the impact of wood pasturing on ecological functions, taxon composition and diversity of the local woodland ecosystem in the Holocene.

A multi-sensor, multi-scale approach to mapping tree mortality in woodland ecosystems

Woodland ecosystems, dominant on nearly 4% of all terrestrial land globally, are faced with a variety of threats, including increasingly prolonged and severe droughts, invasive insect outbreaks, and the rapid spread of pathogens. While many remote sensing methods have been developed for the detection and quantification of mortality in forested environments, woodland ecosystems present unique challenges to accurately mapping tree die-off due to relatively lower canopy covers, smaller and irregularly-shaped tree crowns, and greater influence of understory vegetation and soil cover on reflectance. To address these challenges, we developed a multi-sensor, multi-scale approach combining the analytical strengths of centimeter-resolution unmanned aerial system imagery for interpreting individual tree-level mortality, airborne lidar for crown mapping and quantifying percent canopy mortality, and Landsat imagery for upscaling mortality estimates to a regional scale. This approach utilizes a new algorithm for delineating the shapes of small, irregular woodland tree crowns using lidar. To demonstrate the application of this method, we map the extent and severity of a recent tree mortality event in piñon-juniper (PJ) woodlands of southeastern Utah. Our results suggest that 39% of PJ in this region has experienced some level of mortality, with patches exceeding 50% mortality. An analysis of potential mortality drivers revealed that canopy cover, terrain, and recent winter precipitation conditions are most directly linked with mortality, although the explanatory power of the mortality driver model was low. Our approach demonstrates a methodology that could be used for tree mortality mapping and scaling in a variety woodland ecosystems, and can provide a strong basis for further ecophysiological, ecological, and carbon cycle studies involving woodland tree mortality.

Radiant heating rapidly increases litter flammability through impacts on fuel moisture

BackgroundLitter is the predominant fuel that drives surface fire behavior in most fire-prone forest and woodland ecosystems. The flammability of litter is driven by fuel characteristics, environmental factors, and the interactive effects of the two. Solar radiation can influence litter flammability through its effect on fuel moisture and temperature. The direct influence of radiative heating on flammability, however, is poorly understood and the interactive effects of forest structure, composition, fuels, and micrometeorology may have fine-scale ecological consequences in fire-dependent ecosystems.ResultsIn this study, we measured laboratory flammability of two dominant southeastern USA litter fuels—Pinus palustris Mill. and Quercus stellata Wangenh.—and evaluated the interactive effects of fuel moisture and infrared radiation. Heating of litter fuels increased their flammability primarily through enhanced litter drying. Heated litter quickly became more flammable than unheated litter when fuels were undergoing drying after saturation, a result of more rapid moisture loss. Litter mass did not change the effect of heating on drying rates, but heavier fuels burned with greater flammability.ConclusionsInteractions among surface fuels, overstory structure, and solar heating may be important in understanding fine-scale heterogeneity in both fire behavior and effects, with strong implications toward increasing the effectiveness of prescribed burning.

Anthracological analyses of charcoal production sites at a high spatial resolution: the role of topography in the historical distribution of tree taxa in the northern Vosges mountains, France

The rising demand for charcoal from industrialization during the eighteenth century led to the establishment of a large number of charcoal production sites (CPSs) within the woodland ecosystems of Europe. The CPSs still present today can be investigated to assess the past woodland composition in terms of taxa present and timber size, at a high spatial resolution. The present study was done in the northern Vosges region in France, an area of low mountains covered by woods with some important past industrial sites in several of its valleys. We aimed to investigate the possible role of topographical variables such as altitude and aspect in the distribution of CPSs and in the past distribution of tree taxa. Charcoal production sites were found, identified and sampled in four valley catchment areas, and a numerical model of elevation was used to compute the topography of the landscape. A total of 233 sites were recorded and anthracological (charcoal) samples from 121 of these were analysed. The radiocarbon dates of 20 CPSs range between the late 17th and the early twentieth century AD, which corresponds to the peak of industrial activity in this region. The spatial distribution of CPSs appears to increase in density close to streams, and 14 tree taxa were identified in the charcoal records, with Fagus and Quercus being dominant by far. Our results revealed the strong influence of the direction in which the slope faced on the taxon composition of the anthracological spectra. These results suggest that the local woodland stands which were used to supply the charcoal kilns depended on the local environmental conditions. Furthermore, the composition of the woodland has changed significantly over time, with more Pinus sylvestris at present.

Climate relationships with increasing wildfire in the southwestern US from 1984 to 2015

Over the last several decades in forest and woodland ecosystems of the southwestern United States, wildfire size and severity have increased, thereby increasing the vulnerability of these systems to type conversions, invasive species, and other disturbances. A combination of land use history and climate change is widely thought to be contributing to the changing fire regimes. We examined climate-fire relationships in forest and woodland ecosystems from 1984 to 2015 in Arizona and New Mexico using 1) an expanded satellite-derived burn severity dataset that incorporates over one million additional burned hectares when compared to MTBS data, and 2) climate variables including temperature, precipitation, and vapor pressure deficit (VPD). Regional climate-fire relationships were assessed by correlating annual area burned, area burned at high and low severity, and percent high severity with fire season (May-August) and water-year (October-September) climate variables. We also analyzed relationships between climate and high-severity fire at the scale of the individual fire using a hurdle model. We found that increasing temperature and VPD and decreasing precipitation were associated with increasing area burned regionally, and that area burned at high severity had the strongest relationships with climate metrics. The relationship between climate and fire activity in the Southwest appears to be strengthening since 2000. VPD-fire correlations were consistently as strong as, or stronger than, temperature or precipitation variables alone, both regionally and at the scale of the individual fire. Notably, at the scale of the individual fire, temperature and precipitation were not significant predictors of fire activity. Thus, our results support the use of VPD as a more integrative climate metric to forecast fire activity. We suggest that the strong relationship between VPD and fire activity may be useful to assess the likelihood of high-severity fire occurrence through continued development of the high-severity fire threshold model we present. The link between increasing aridity and increasing wildfire activity suggests a future with more fire in Southwest forests and woodlands with projected warming, underscoring the urgency of restoration in dry forests to reduce the likelihood of uncharacteristic, large high-severity fires.

Earth Emotions: New Words for a New World by Glenn A. Albrecht

Reviewed by: Earth Emotions: New Words for a New World by Glenn A. Albrecht Ben De Bruyn (bio) Earth Emotions: New Words for a New World by Glenn A. Albrecht. Ithaca, NY: Cornell University Press, 2019. 256 pp. How does life on an increasingly degraded planet make us feel, how should it make us feel, and how can we talk about those environmental emotions in ways that foster more convivial futures? These are urgent questions at the start of the twenty-first century, for runaway climate change is impacting human moods as well as nonhuman atmospheres, mental health research claims, and forces us to rethink our psychology and vocabulary alongside our economy and technology. In this context, Australian ecophilosopher Glenn Albrecht has coined the term solastalgia to designate "the homesickness you have when you are still at home," "the lived experience of negative environmental change" (p. 200), and this term is now increasingly employed in academic debates and popular culture to contemplate the psychological fallout of global pollution, biodiversity loss, and destabilized weather. Building on that impressive success, Albrecht's book Earth Emotions: New Words for a New World (2019) develops his pioneering remarks on solastalgia in ways that are fruitful as well as flawed because they enrich the cultural debate on environmental emotions but fail to recognize its full complexity. Summarizing his argument, this review pinpoints the study's merits and limitations while reflecting on the underlying view of nature, emotions, and culture. To my mind, Albrecht deserves praise for his attempt to construct a new vocabulary for the Anthropocene psyche but also criticism for his limited dialogue with other researchers. To be clear, Earth Emotions is a bracing attempt to advance the debate on global heating, which constitutes a human health and identity crisis, Albrecht convincingly argues, alongside a widening biological and social catastrophe. In going forward, we will need to address that psychological and existential damage too, and the concept of solastalgia helpfully alerts us to the unique form of "desolation" that arises when the fauna [End Page 213] and flora, the weather and the seasons change around us (p. 38)—a negative mindset that will only spread and intensify as those changes accelerate in the coming years. Like climate change, solastalgia is here to stay, and Albrecht skillfully explains its features via detailed comparisons with related forms of ecological grief and hope. Furthermore, Albrecht is right that our course can only be reversed with the help of a new cultural narrative that counteracts bad "Earth emotions" like ecophobia (p. ix) without parroting facile slogans involving "sustainability" and "resilience" (p. 93), and that underlines the priority of the planet we are living on—in sharp contrast to the fantasies of entrepreneurial "space invaders" like Jeff Bezos and Elon Musk (p. 161). In line with recent research on vegetal life and multispecies knots, Albrecht also makes a compelling case that this new cultural narrative should cultivate empathy for animals, plants, and fungi, and for symbiotic processes involving life forms that are invisible to the human senses, like the bacterial life inside our bodies and inside the earth's crust. In one memorable example of this multispecies entanglement, he explains how small kangaroo-like marsupials called woylies help to make water and nutrients available to Australian woodland ecosystems by digging into the soil and breaking up waxy eucalyptus residues that otherwise turn the ground hard and water-repellent (p. 125). Instead of adopting the morose tone of much Anthropocene discourse, moreover, Albrecht feels that this new narrative should provide optimistic conceptual tools for what he names "Generation Symbiocene" (p. xi). Those who want to address ecological grief will accordingly find an invigorating roadmap here, which follows a confident trajectory from negative to positive earth emotions. Even more interesting, in my opinion, is that this argument about eco-affects is embedded in the story of Albrecht's life and research on Australian communities impacted by drought and the mining industry, especially in the formerly bucolic Hunter Valley (pp. 49-60). Emphasizing the Australian connection further, Albrecht singles out the relatively obscure work of twentieth-century writer Elyne Mitchell as a precursor of recent ecological thinking on a par with that...

Effect of charcoal production and woodland type on soil organic carbon and total nitrogen in drylands of southern Mozambique

African woodland ecosystems function as important reservoirs for soil organic carbon (SOC) and total nitrogen (TN). However, these ecosystem functions are particularly sensitive to social-ecological factors, the impacts of which remain understudied. Here, we examine how SOC and TN and other soil properties vary across woodland types and how charcoal production, the main source of woodland disturbance in the study area, changes these factors in dry woodlands of southern Africa, focusing on three woodland ecosystems that represent the main types in southern Mozambique: Androstachys forest, Combretum woodland and Mopane woodlands. Drawing on data from soil surveys at 0–5 cm and 0–30 cm depth in different vegetation types as well as both distant from and proximate to sites of active charcoal production, we estimate that these woodlands in Mabalane District store on average 19 ± 10 (±SE) Mg ha−1 of SOC, and 2.2 ± 0.9 Mg ha−1 of TN at 0–30 cm, significantly lower than values reported for other woodlands in the region such as Miombo. Our analysis shows that the woodland types do not differ in terms of the amount of SOC and TN stored in soil, and that soil in the charcoal kilns had twice the amount of SOC (30.0 ± 1.8 Mg ha−1) and TN (4.5 ± 0.5 Mg ha−1) compared with non-charcoal soils. This study adds to our understanding of the impact of charcoal production on soil SOC and TN in dry woodlands of southern Africa, and demonstrates some localised impacts of charcoal production. We discuss the implications of our findings in the light of emerging carbon-based payments for ecosystem services programmes in the region.

Water-use efficiency in a semi-arid woodland with high rainfall variability.

As the ratio of carbon uptake to water use by vegetation, water-use efficiency (WUE) is a key ecosystem property linking global carbon and water cycles. It can be estimated in several ways, but it is currently unclear how different measures of WUE relate, and how well they each capture variation in WUE with soil moisture availability. We evaluated WUE in an Acacia-dominated woodland ecosystem of central Australia at various spatial and temporal scales using stable carbon isotope analysis, leaf gas exchange and eddy covariance (EC) fluxes. Semi-arid Australia has a highly variable rainfall pattern, making it an ideal system to study how WUE varies with water availability. We normalized our measures of WUE across a range of vapour pressure deficits using g1 , which is a parameter derived from an optimal stomatal conductance model and which is inversely related to WUE. Continuous measures of whole-ecosystem g1 obtained from EC data were elevated in the 3days following rain, indicating a strong effect of soil evaporation. Once these values were removed, a close relationship of g1 with soil moisture content was observed. Leaf-scale values of g1 derived from gas exchange were in close agreement with ecosystem-scale values. In contrast, values of g1 obtained from stable isotopes did not vary with soil moisture availability, potentially indicating remobilization of stored carbon during dry periods. Our comprehensive comparison of alternative measures of WUE shows the importance of stomatal control of fluxes in this highly variable rainfall climate and demonstrates the ability of these different measures to quantify this effect. Our study provides the empirical evidence required to better predict the dynamic carbon-water relations in semi-arid Australian ecosystems.

Solar radiation exposure accelerates decomposition and biotic activity in surface litter but not soil in a semiarid woodland ecosystem in Patagonia, Argentina

Photodegradation of senescent plant material has been identified as an important vector of aboveground carbon (C) loss in aridland ecosystems, but the consequences for biotic activity and soil C in the field are not well understood. We established an experiment in a semiarid woodland in Patagonia, Argentina with attenuation of solar radiation and additions of leaf litter to evaluate impacts of photodegradation on changes in labile C and biotic activity in aboveground litter and surface soils. Litter decomposition was significantly accelerated by exposure to solar radiation. Moreover, labile sugars (hexoses and pentoses), microbial enzymatic activity (β-glucosidase activity) and available carbohydrates for cellulase degradation (saccharification) all significantly increased in sunlight-exposed litter. None of these stimulatory effects were observed in the surface soils exposed to sunlight. On the contrary, soil microbial biomass and β-glucosidase activity in surface soils were significantly greater only with litter addition and attenuated sunlight. Our results suggest that photodegradation of plant litter (production of volatile compounds through photochemical mineralization) and photofacilitation (stimulation of biotic activity due to change in litter chemistry with exposure to sunlight) generate rapid turnover of C in aboveground litter. The consequences of this accelerated C turnover may be that a fraction of leaf litter decomposes and is directly released back to the atmosphere as CO2 and never enters soil organic matter pool. Taken together, these results highlight the functional importance of solar radiation in determining the C balance in semiarid ecosystems.

Fire-mediated habitat change regulates woodland bird species and functional group occurrence.

In an era characterized by recurrent large wildfires in many parts of the globe, there is a critical need to understand how animal species respond to fires, the rates at which populations can recover, and the functional changes fires may cause. Using quantified changes in habitat parameters over a ~400-yr post-fire chronosequence in an obligate-seeding Australian eucalypt woodland, we build and test predictions of how birds, as individual species and aggregated into functional groups according to their use of specific habitat resources, respond to time since fire. Individual bird species exhibited four generalized response types to time since fire: incline, decline, delayed, and bell. All significant relationships between bird functional group richness or abundance and time since fire were consistent with predictions based on known time-since-fire-associated changes in habitat features putatively important for these bird groups. Consequently, we argue that the bird community is responding to post-fire successional changes in habitat as per the habitat accommodation model, rather than to time since fire per se, and that our functional framework will be of value in predicting bird responses to future disturbances in this and other obligate-seeder forest and woodland ecosystems. Most bird species and functional groups that were affected by time since fire were associated with long-unburned woodlands. In the context of recent large, stand-replacement wildfires that have affected a substantial proportion of obligate-seeder eucalypt woodlands, and the multi-century timescales over which post-fire succession occurs, it would appear preferable from a bird conservation perspective if fires initiating loss of currently long-unburned woodlands were minimized. Once long-unburned woodlands are transformed by fire into recently burned woodlands, there is limited scope for alternative management interventions to accelerate the rate of habitat development after fire, or supplement the resources formerly provided to birds by long-unburned woodlands, with the limited exception of augmenting hollow availability for key hollow-nesting species.

Using Q Methodology to Explore Risk Perception and Public Concern about Tree Pests and Diseases: The Case of Ash Dieback

This paper seeks to address the need for a more nuanced understanding of public perceptions of risk-related events by investigating the nature of and drivers for a ‘concerned public’ to an environmental issue, using the case study of the ash dieback outbreak in the UK. Q Methodology, an approach that combines both quantitative and qualitative data through factor analysis to identify different ways of thinking about a particular issue, was used to investigate the subjective response of local publics to ash dieback in East Kent, England, one of the early outbreak locations. Five narratives are identified, distinguishing perceptions of risk and management preferences: (1) call for better biosecurity; (2) resilient nature and techno-scientific solutions; (3) fatalistic; (4) disinterested; and (5) pro-active citizens. Four narratives demonstrated concern about the impacts of ash dieback on woodland ecosystems, but beliefs about whether the disease arrived in the UK on infected imported nursery stock or on windblown spores varied. The results of this study contribute to improving understanding of the drivers of differing public perceptions of tree health risks, an important consideration for designing socially acceptable strategies for managing tree pests and diseases, and other environmental risks, in the future.

Small carnivoran fauna of the Mascall Formation, Crooked River Basin, central Oregon

ABSTRACTThe Hemingfordian North American Land Mammal Age is a poorly known time period, although recently discovered sites in central Oregon have begun to cast light on a diverse mammalian fauna. Here, we describe four small carnivorans new to this region, one of which is a new species. Cryptailurus tinaynakti, sp. nov., is a hypercarnivorous feliform. UOMNH F-70218 is the dp4 of a diminutive mustelid similar in morphology to that of extant martens, but likely of a new species based upon discussed patterns in mustelid deciduous dentition. The occurrence of two additional species, Leptocyon leidyi and Bassariscus antiquus, increases both their geographic and temporal ranges. The early to middle Miocene was a time of transition from sparse woodland to grassland ecosystems in much of North America. The Hemingfordian fauna of the Pacific Northwest inhabited a diverse wet woodland ecosystem, surprisingly rich in carnivorans. With the description of these additional small taxa, we can now get a clearer picture of what must have been a diverse assemblage of mammals with a variety of ecological roles in an undersampled period of time.

Testing the relative sensitivity of 102 ecological variables as indicators of woodland condition in the New Forest, UK

Abstract Forests globally are facing an increasing number of threats from modified disturbance regimes, novel stressors and changing environmental conditions. This has ultimately resulted in declines in the ecological condition of many forest and woodland ecosystems, leading to widespread tree mortality and stand dieback. Effective indicators of overall woodland ecological condition are therefore needed for environmental monitoring and to support management responses. To test the effectiveness of different variables that could potentially be used as indicators of woodland condition, 102 variables that describe woodland structure, composition, functioning, edaphic conditions and disturbance regimes were assessed along 12 replicate gradients of beech stand dieback. Results indicated that 35 variables differed significantly between at least two stages of the dieback gradient, indicating their sensitivity to stand dieback. Seven of these indicators related to woodland species composition, two to functional processes, 20 to structural features, four to edaphic conditions, and two to disturbance regimes. These results demonstrate that effective indicators can potentially be identified for each of the ecological categories. Effective composition indicators included species richness of ectomycorrhizal fungi, ground flora and epiphytic lichens; functional indicators were soil respiration rate and net nitrification rate; edaphic conditions included soil Na:Ca ratio, exchangeable sodium, total carbon, Ca:Al ratio; structural indicators included canopy openness, litter cover, sward height, and volume of deadwood, and for disturbance the indicator was Equus dung density. Other measures, such as shrub cover and species richness of carabid beetles and spiders, were not found to vary significantly along the dieback gradients, and were therefore not identified as effective indicators. These results demonstrate the value of gradient analysis for evaluating indicators of woodland condition, but also highlight the need for multi-site studies to identify indicators with widescale applicability.

The effects of increasing land use intensity on soil nematodes: A turn towards specialism

Abstract The ecosystem services that humans obtain from the soil are strongly linked to the soil's biota. There is ample evidence that intensive agriculture has a negative effect on the soil's biological diversity. While in other ecosystems, habitat specialists are at a higher risk of extinction due to human impacts than generalists, we have no evidence of whether this holds true for soil biota. We calculated the realized niche width for soil nematodes using co‐occurrence data. We compared these with ecological traits. We then calculated an index of community specialization and tested whether land use intensity leads to decreases in the index of community specialization, taxon richness, diversity and to changes in nematode abundance. The resulting realized niche widths did not correlate with ecological traits such as feeding group, body mass or c‐p class. While it is possible that there are no relationships between these traits and the realized niche width, it is likelier that food availability, pH tolerance, or host breadth are more important factors in explaining niche width. Contrary to our expectations, the lowest community specialization levels were found in soils with the lowest human intervention (shrubland–woodland ecosystems), while grasslands, dairy farms and arable farms had an overall higher level of specialization. Weather variables and land use intensity explained 66% of the variation in the index of community specialization in sandy soils. We found highest richness and diversity at intermediate levels of disturbance (grasslands and dairy farms). The lowest abundances were found on shrubland–woodland systems. Dairy farms on sand and clay had similar indices of community specialization, whereas peaty soils fostered a higher proportion of habitat specialists. We argue that farmland supposes a stable environment for organisms with shorter life spans. Agricultural management strives to lower disturbances, allowing shorter lived organisms to escape pressures otherwise present in nature, such as drought or nutrient deficiencies during the growing season. In very disturbed systems, however, specialists may also suffer from negative effects of land use intensity. This co‐occurrence method to assess niche width opens the door to estimating the soil community's niche breadth, for which resource‐based methods are difficult to implement. A free Plain Language Summary can be found within the Supporting Information of this article.

Accounting for aboveground carbon storage in shrubland and woodland ecosystems in the Great Basin

AbstractImproving the accuracy of carbon accounting in terrestrial ecosystems is critical for understanding carbon fluxes associated with land cover change, with significant implications for global carbon cycling and climate change. Semi‐arid ecosystems account for an estimated 45% of global terrestrial ecosystem area and are in many locations experiencing high degrees of degradation. However, aboveground carbon accounting has largely focused on tropical and forested ecosystems, while drylands have been relatively neglected. Here, we used a combination of field estimates, remotely sensed data, and existing land cover maps to create a spatially explicit estimate of aboveground carbon storage within the Great Basin, a semi‐arid region of the western United States encompassing 643,500 km2 of shrubland and woodland vegetation. We classified the region into seven distinct land cover categories: pinyon‐juniper woodland, sagebrush steppe, salt desert shrub, low sagebrush, forest, non‐forest, and other/excluded, each with an associated carbon estimate. Aboveground carbon estimates for pinyon‐juniper woodland were continuous values based on tree canopy cover. Carbon estimates for other land cover categories were based on a mean value for the land cover type. The Great Basin ecosystems contain an estimated 295.4 Tg in aboveground carbon, which is almost double the previous estimates that only accounted for forested ecosystems in the same area. Aboveground carbon was disproportionately stored in pinyon‐juniper woodland (43.7% carbon, 16.9% land area), while the shrubland systems accounted for roughly half of the total land area (49.1%) and one‐third of the total carbon. Our results emphasize the importance of distinguishing and accounting for the distinctive contributions of shrubland and woodland ecosystems when creating carbon storage estimates for dryland regions.

Changes in tree species diversity, composition and aboveground biomass in areas of fuelwood harvesting in miombo woodland ecosystems of southern Malawi

ABSTRACTFuelwood is an essential forest product for small-holder farmers in the tropics, but fuelwood harvesting may cause forest degradation and impact ecosystem services. Understanding tree species composition, diversity and biomass changes in forests with active fuelwood collection is important for informing sustainable forest harvesting. In the miombo woodlands of southern Malawi, using forest plots, we investigated: 1) if forests with fuelwood harvesting (n = 50) have different tree, sapling and seedling stem density, species diversity, species composition, and aboveground biomass (AGB) than forests with minimal use (n = 36); and 2) if forest product harvesting pressure and access are predictors of tree stem density, diversity and AGB. We found a significant reduction in tree diversity and AGB but not stem density, and different species composition in areas with fuelwood harvesting compared to reference sites. For saplings, stem density was higher and species composition was different in fuelwood harvesting sites. Seedling Shannon index and Simpson’s diversity were lower in fuelwood harvesting sites. Harvesting pressure and access were predictors of AGB and tree stem density. The reduced AGB and tree species diversity may hinder collection of fuelwood and other forest products, and may reduce ecosystem functioning. Exploring the possibility of forest landscape restoration in the area could be beneficial.

Drivers of temperate woodland condition through time in an agricultural landscape

AbstractConversion of natural woodlands to grazing pastures is a major driver of biodiversity loss. In response to this threat, regenerative management approaches have been proposed to balance agriculture with biodiversity conservation. Yet rigorous experiments investigating the effectiveness of such approaches are rare. We used time‐series data from a broad‐scale experiment in south‐eastern Australian woodlands to explore the effects of agricultural practices and environmental factors on regeneration, bare ground, and native and exotic cover and richness. Our study included historical fertilization, three past grazing regimes (continuous, short‐conversion rotational, and long‐conversion rotational), two present‐day grazing measures (grazing duration and stocking rate), and three environmental covariates (natural soil fertility, native woody cover, and rainfall). We found that fertilizer application was associated with altered trajectories of native overstorey cover, native plant richness, exotic cover, and bare ground. Changes in woodland condition also were associated with a combination of present‐day grazing and environmental drivers. Natural regeneration, native plant richness, and native herb cover were negatively associated with increased grazing intensity. Conversely, increased landscape‐scale native woody cover and local‐scale natural soil fertility were associated with increases in native overstorey cover and native plant richness and decreases in exotic cover and bare ground.Our results indicate that land‐use history, present grazing intensity, and landscape context alter woodland ecosystem responses to intervention. This may explain why some conservation actions fail to meet objectives. Our results indicate that the effectiveness of conservation actions can be improved by considering the combined influence of past and present agricultural management and landscape context on woodland condition.

Predation risk is a function of alternative prey availability rather than predator abundance in a tropical savanna woodland ecosystem

Typically, factors influencing predation risk are viewed only from the perspective of predators or prey populations but few studies have examined predation risk in the context of a food web. We tested two competing hypotheses regarding predation: (1) predation risk is dependent on predator density; and (2) predation risk is dependent on the availability of alternative prey sources. We use an empirical, multi-level, tropical food web (birds–lizards–invertebrates) and a mensurative experiment (seasonal fluctuations in abundance and artificial lizards to estimate predation risk) to test these hypotheses. Birds were responsible for the majority of attacks on artificial lizards and were more abundant in the wet season. Artificial lizards were attacked more frequently in the dry than the wet season despite a greater abundance of birds in the wet season. Lizard and invertebrate (alternative prey) abundances showed opposing trends; lizards were more abundant in the dry while invertebrates were more abundant in the wet season. Predatory birds attacked fewer lizards when invertebrate prey abundance was highest, and switched to lizard prey when invertebrate abundance reduced, and lizard abundance was greatest. Our study suggests predation risk is not predator density-dependent, but rather dependent on the abundance of invertebrate prey, supporting the alternative prey hypothesis.

Diet preferences and climate inferred from oxygen and carbon isotopes of tooth enamel of Tarbosaurus bataar (Nemegt Formation, Upper Cretaceous, Mongolia)

Stable isotopes of oxygen and carbon of tooth enamel are increasingly being used as tracers to study palaeoecology and the diet preferences of fossil vertebrates. We serially sampled tooth enamel carbonate along the growth axes of five Early Maastrichtian carnivorous dinosaur teeth (Tarbosaurus bataar tyrannosaurid) from the Nemegt Formation, Mongolia, in order to identify seasonal climatic variations and determine the diet of this apex predator. Additional bulk samples of dentine, bone, and surrounding sediment were analyzed in order to exclude diagenetic obfuscation of the isotopic record. Enamel samples of potential prey species for dietary studies were also analyzed. In the case of the largest specimens, the sampled teeth usually recorded annual cycles ranging between two-thirds and a full year. Fluctuations in δ18O values in tyrannosaurid teeth suggest seasonality (high annual temperatures with distinct precipitation/humidity maxima during summer months) with mean annual temperatures (MAT) ten degrees higher than those of present-day Mongolia. The seasonal pattern of δ18O shows similarities to that of the modern-day Shijiazhuang Global Network of Isotopes in Precipitation station, northern China, and suggests that the Nemegt biota flourished when exposed to a cool temperate monsoon-influenced climate. Herbivore and carnivore carbon isotopes (δ13C) values from tooth enamel imply the presence of a woodland ecosystem dominated by coniferous trees such as Araucariaceae, and are consistent with the hypothesis that large sauropods and hadrosaurids were the preferred prey of Tarbosaurus. Mean annual precipitation (MAP), based on the relationship between modern-day C3 gymnosperms and local average MAP, is estimated at 775–835 mm/yr. These results show that large theropod teeth can serve as valuable archives for palaeoenvironmental studies.

Effects of greenway development on functional connectivity for bats

1 Abstract Fragmentation of ecosystems is continuing worldwide, posing increasing pressures to and loss of biodiversity. Disused transport corridors such as old railways and tramways often return to semi-naturalness, and are increasingly upcycled into multi-use, non-motorised public Greenway infrastructure. This study examines bat activity within a proposed rural Greenway corridor in Ireland. Development scenarios are simulated to predict impacts to woodland ecosystem functional connectivity using Probability of Connectivity (PC) index. Generalised Linear Modelling predicts associations of species activity to Greenway corridor habitat and habitat structure. Spatially explicit connectivity models indicate significant impacts to ecosystem connectivity can arise from Greenway development scenarios, such as decreasing connectivity in half, or increasing connectivity four-fold. Species activity modelling identified habitat conditions along the Greenway route that suggest on-going corridor effects and associations to particular habitats and structure, emphasising the importance to consider a sensitive approach to developing disused infrastructure into Greenways. Conservation implications Potential significant increases in woodland ecosystem reachability for bats are achievable by conserving canopy cover over Greenway corridors. Species-specific habitat modelling results presented are directly applicable to guide woodland enhancement for the sensitive conservation of Greenway woodland habitat, maximising their multi-functional use and connectivity potential. Opportunities therefore exist for European Greenways to conserve and enhance ecosystem connectivity, providing landscape-scale solutions to the problem of increasing ecosystem fragmentation.