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Masting is the synchronous and highly variable production of fruit within a population. Although several hypotheses have been proposed to explain why and how masting evolved in plants as a reproductive strategy, the factors that trigger a large reproductive effort in a particular year are still not well understood. While both weather and resources have been proposed to play an important role, testing these hypotheses has been challenging due to a lack of long-term data and appropriate experimental designs. In this manuscript, we used 18 years of acorn production data to analyze the relationship between resources, weather, and masting in black oak (Quercus velutina) and chestnut oak (Q. montana). The data were collected in southeast Ohio as part of the Fire and Fire Surrogate (FFS) study, which applied silvicultural treatments (i.e., thinning and prescribed fires) to reduce competition and manipulate resources. We found species-specific responses to the thinning and fire treatments, with an overall increase in acorn production for chestnut oak in the thin + burn treatment and an increase for black oak in the thin-only treatment compared to the control. Chestnut oak reproduction also had strong positive relationships with warm spring temperatures, and a positive change in summer temperatures compared to the previous year (i.e., summer temperatures that went from cool to warm). For black oak, warm spring temperatures increased acorn production while later starts to spring warming the year before decreased acorn production. These results support the hypotheses that both resources and weather (as a cue and as a limiting factor) are important for masting in oaks. Thus, both factors should be included in predictive models for acorn production under current and future climate conditions.

1. Changes of grazing pressure and climate have been identified as drivers of woody encroachment in subalpine pastures, but disentangling their relative importance remains challenging. It is particularly unclear if grazing alone can mitigate potential climate change impacts on encroachment. 2. We used the dynamic vegetation model LandClim to simulate how multiple biotic and abiotic factors influence the rate of woody encroachment (i.e. how changes in temperature and precipitation influence woody and herbaceous vegetation, and interactions with grazing). We simulated a 61-ha subalpine pasture in Switzerland near tree line. Currently, 21% of the pasture is covered by woody plants. 3. If current grazing levels are maintained, almost all climate change scenarios showed an increase in woody cover. Under the RCP 4.5 and RCP 8.5 scenarios, there was a mean encroachment rate of 0.24% and 0.15% per year respectively. 4. Large variation among climate model chains with RCP 8.5 was found, due to variations in precipitation. Generally, decreasing precipitation caused woody encroachment to slow down, even under very low grazing pressures. 5. Using a sensitivity analysis with all possible combinations of grazing pressure, temperature and precipitation changes, we found that woody encroachment rates were most sensitive to changes in grazing pressure. Precipitation change was the second most important factor, while temperature changes were least important. 6. Synthesis and applications. Modelling shows that increasing grazing pressure in subalpine pastures can strongly reduce woody encroachment and mitigate climate change impacts on woody encroachment., Journal of Applied Ecology, 59 (7), ISSN:0021-8901, ISSN:1365-2664

The relationship between disturbances and diversity remains uncertain, especially in forest landscapes where large spatial extents need to be considered, dynamics are slow, and disturbance interactions are common. To analyse the individual and combined effects of ungulate browsing and wind disturbance on tree species diversity at the landscape scale. We used a dynamic forest landscape model to simulate the effects of browsing and wind disturbances (i.e., frequency and windthrow size) on tree species diversity in four mountain landscapes in Central Europe. Using boosted regression trees, we analysed the relative importance of each disturbance type for diversity at different layers (i.e., regeneration versus overstorey, and all tree sizes), the shapes of the diversity–disturbance relationships and the combined effect of wind and browsing disturbances on diversity. Across all landscapes, browsing and windthrow were equally important for tree species diversity when considering all forest layers, but no consistent patterns could be observed for the regeneration and overstorey layer. The shape of the disturbance–diversity relationships differed between disturbance types. More frequent and severe windthrow events typically increased diversity almost linearly, while browsing showed a non-linear response with the highest diversity at intermediate browsing pressure. However, these relationships were not consistent across the four landscapes. Tree species diversity can be influenced by both browsing and windthrow disturbances. Forested landscapes are likely to experience multiple disturbances, and their relative influence on diversity needs to consider their different spatial and temporal scales.

Under future climate change, plant species are expected to shift their ranges in response to increasing temperatures and altered precipitation patterns. As seeds represent the single opportunity for plants to move, it is critical to quantify the factors that influence reproduction. While total seed production is clearly important, seed quality is equally as critical and often overlooked. Thus, to quantify how environmental and tree‐level characteristics affect seed quality and quantity, the reproductive output of red maple (Acer rubrum) was measured along an elevation gradient in the Monongahela National Forest, WV. A variety of individual‐level characteristics were measured (e.g., DBH, canopy area, height, and tree cores were taken to quantify growth), and seed traps were placed under seed‐bearing trees to collect samaras and quantify total seed production. A random subsample of collected seeds from each tree was micro‐CT scanned to determine embryo volume, photographed for morphology measurements, and used for germination trials. The number of seeds produced was negatively affected by frost events during flowering, and stand density. The trees with the most seeds also showed reduced growth in recent years. Only 63% of scanned seeds showed embryo development, and of those seeds—only 23% germinated. The likelihood of embryo presence increased as growth rate decreased, while embryo size increased with tree height, smaller DBH, and in areas dominated by hemlock. Both larger embryo volume and larger overall seed size increased the likelihood of germination. The results highlight the importance of including seed quality in addition to seed quantity for a more complete representation of reproductive output., Seed production and germination are critical processes for the ability of plants to respond to climate change. We measured both seed production and seed quality for red maple along an elevation gradient. We established that seed production alone is not an accurate measure for reproduction, as only 63% of seeds contained embryos and embryo volume was the only factor which influenced germination success. Individual tree characteristics (e.g., DBH, age, height, and growth rate) were more important for predicting seed quality and quantity than weather. In fact, the only weather variable which was significant was the number of frost‐free days during flowering, which had a positive impact on number of seeds produced.

Although dispersal is generally viewed as a crucial determinant for the fitness of any organism, our understanding of its role in the persistence and spread of plant populations remains incomplete. Generalizing and predicting dispersal processes are challenging due to context dependence of seed dispersal, environmental heterogeneity and interdependent processes occurring over multiple spatial and temporal scales. Current population models often use simple phenomenological descriptions of dispersal processes, limiting their ability to examine the role of population persistence and spread, especially under global change. To move seed dispersal ecology forward, we need to evaluate the impact of any single seed dispersal event within the full spatial and temporal context of a plant’s life history and environmental variability that ultimately influences a population’s ability to persist and spread. In this perspective, we provide guidance on integrating empirical and theoretical approaches that account for the context dependency of seed dispersal to improve our ability to generalize and predict the consequences of dispersal, and its anthropogenic alteration, across systems. We synthesize suitable theoretical frameworks for this work and discuss concepts, approaches and available data from diverse subdisciplines to help operationalize concepts, highlight recent breakthroughs across research areas and discuss ongoing challenges and open questions. We address knowledge gaps in the movement ecology of seeds and the integration of dispersal and demography that could benefit from such a synthesis. With an interdisciplinary perspective, we will be able to better understand how global change will impact seed dispersal processes, and potential cascading effects on plant population persistence, spread and biodiversity., Although dispersal is generally viewed as a crucial determinant for the fitness of any organism, our understanding of its role in the persistence and spread of plant populations remains incomplete. In this perspective, we provide guidance on integrating empirical and theoretical approaches that account for the context dependency of seed dispersal to improve our ability to generalize and predict the consequences of dispersal, and its anthropogenic alteration, across systems. With an interdisciplinary perspective, we will be able to better understand how global change will impact seed dispersal processes, and potential cascading effects on plant population persistence, spread and biodiversity.

Mountain forests provide a wide range of ecosystem services (ES, e.g., timber production, protection from natural hazards, maintaining biodiversity) and are especially sensitive to climate change. Dynamic vegetation models are commonly used to project climate change impacts on forests, but the sensitivity of process-based forest landscape models (FLMs) to uncertainties in climate input data has received little attention, especially regarding the response of ES. Using a dry inner-Alpine valley in Switzerland as a case study, we tested the sensitivity of a process-based FLM to different baseline climate data, lapse rates, and future climate change derived from different climate model combination chains and downscaling methods. Under the current climate, different sources of baseline climate accounted for the majority of the variation at lower elevations, while differences in lapse rates caused large variability at higher elevations. Under climate change, differences between climate model chains were the greatest source of uncertainty. In general, the largest differences for species were found at their individual regional distribution limits, and the largest differences for ES were found at the highest elevations. Thus, our results suggest that the greatest uncertainty for simulating forest ES is due to differences between climate model chains, and we recommend using as many climate scenarios as possible when projecting future forest response to climate change. In addition, care should be taken when evaluating climate impacts at landscape locations that are known a priori to be sensitive to climate variation, such as high-elevation forests.

Hickories (Carya spp.) are common species in eastern US forests. Despite being a noted component of the most prevalent forest type in the eastern US, remarkably little is known about the ecology and silvics of the genera, especially compared to oaks (Quercus spp.). To improve our understanding about the dynamics of hickories in stand development and forest succession, we used a variety of datasets from oak-hickory forests of the Central Hardwood Region to assess growth, physiology, and demography. Our findings suggest that hickories may have a conservative root-centered growth strategy that exceeds that of oaks, with highly plastic physiology. This allows for long-term persistence of hickories in the mid and understory while being responsive to favorable increases in available light. The reproduction dynamics of hickories suggest a gradual and consistent recruitment to the mid and overstory in contrast to the single, unimodal age distribution of oaks following historic disturbance. This is achieved by periods of higher growth rates and lower mortality rates, especially in subordinate canopy positions when compared to oaks. These findings suggest that contemporary removal of historic disturbance regimes may continue to support hickory recruitment to the overstory, but active forest management is necessary to maintain the oak-hickory forest type in the Central Hardwood Region.

Pasture-woodlands are semi-natural landscapes that result from the combined influences of climate, management, and intrinsic vegetation dynamics. These landscapes are sensitive to future changes in land use and climate, but our ability to predict the impact on ecosystem service provisioning is limited due to the disparate scales in time and space that govern their dynamics. To develop a process-based model to simulate pasture-woodland landscapes and the provisioning of ecosystem services (i.e., livestock forage, woody biomass and landscape heterogeneity). We modified a dynamic forest landscape model to simulate pasture-woodland landscapes in Switzerland. This involved including an annual herbaceous layer, selective grazing from cattle, and interactions between grazing and tree recruitment. Results were evaluated within a particular pasture, and then the model was used to simulate regional vegetation patterns and livestock suitability for a ~198,000 ha landscape in the Jura Vaudois region. The proportion of vegetation cover types at the pasture level (i.e., open, semi-open and closed forests) was well represented, but the spatial distribution of trees was only broadly similar. The entire Jura Vaudois region was simulated to be highly suitable for livestock, with only a small proportion being unsuitable due to steep slopes and high tree cover. High and low elevation pastures were equally suitable for livestock, as lower forage production at higher elevations was compensated by reduced tree cover. The modified model is valuable for assessing landscape to regional patterns in vegetation and livestock, and offers a platform to evaluate how climate and management impact ecosystem services.

There is growing realization that intraspecific variation in seed dispersal can have important ecological and evolutionary consequences. However, we do not have a good understanding of the drivers or causes of intraspecific variation in dispersal, how strong an effect these drivers have, and how widespread they are across dispersal modes. As a first step to developing a better understanding, we present a broad, but not exhaustive, review of what is known about the drivers of intraspecific variation in seed dispersal, and what remains uncertain. We start by decomposing ‘drivers of intraspecific variation in seed dispersal’ into intrinsic drivers (i.e. variation in traits of individual plants) and extrinsic drivers (i.e. variation in ecological context). For intrinsic traits, we further decompose intraspecific variation into variation among individuals and variation of trait values within individuals. We then review our understanding of the major intrinsic and extrinsic drivers of intraspecific variation in seed dispersal, with an emphasis on variation among individuals. Crop size is the best-supported and best-understood intrinsic driver of variation across dispersal modes; overall, more seeds are dispersed as more seeds are produced, even in cases where per seed dispersal rates decline. Fruit/seed size is the second most widely studied intrinsic driver, and is also relevant to a broad range of seed dispersal modes. Remaining intrinsic drivers are poorly understood, and range from effects that are probably widespread, such as plant height, to drivers that are most likely sporadic, such as fruit or seed colour polymorphism. Primary extrinsic drivers of variation in seed dispersal include local environmental conditions and habitat structure. Finally, we present a selection of outstanding questions as a starting point to advance our understanding of individual variation in seed dispersal., Intraspecific variation in the quantity and quality of seed dispersal has important ecological and evolutionary consequences, yet it is generally ignored in favour of simply using population mean values. In a broad but not exhaustive review we show that drivers of intraspecific variation in seed dispersal are diverse and pervasive. These include both intrinsic (i.e. variation in traits of individual plants) and extrinsic (i.e. variation in ecological context) drivers. Further, these drivers appear to interact frequently in complex ways. Current theory does not include or account for these complex and interacting drivers.

The mycorrhizal-associated nutrient economy hypothesis proposes a strong connection between plant and fungal traits and the dominant form of soil nutrients. If true, then shifting from an organic to an inorganic nutrient economy should benefit arbuscular mycorrhizal (AM) trees because they are more suited to acquiring inorganic forms of nutrients and have limited decomposing capabilities when compared with ectomycorrhizal (ECM) trees. An inorganic nutrient economy was experimentally promoted by applying inorganic phosphorus (P) fertiliser and/or elevating soil pH with lime in three Allegheny Plateau mixed-mesophytic forests. Trees were measured over seven growing seasons to determine how growth responded to the treatments based on mycorrhizal association. AM-associated trees showed increased growth in response to increased inorganic nutrients, but ECM tree growth was suppressed when compared with the control. We also observed that understory and mid-story trees responded to the treatments, but large overstory trees showed no significant growth response. Results support the hypothesis that AM trees respond positively to an inorganic nutrient economy. While raising pH in acidic soils can be detrimental to ECM tree growth, the exact mechanism for this response is unclear.

Converting monocultures to mixed-species stands is thought to be a promising approach to increase forest productivity and resilience, while additionally providing other ecosystem goods and services (EGS). However, the importance of tree species composition and structure remains unclear, particularly beyond the stand scale due to the difficulty of conducting comprehensive, long-term experiments. To compare the ability of different tree species mixtures to provide various EGS at the landscape scale. We used a dynamic forest landscape model to simulate all possible combinations of dominant tree species for two landscapes; a high-elevation alpine region (Dischma valley, Switzerland) and a lowland valley (Mt. Feldberg, Germany). We evaluated multiple EGS, including protection from gravitational hazards, aboveground biomass, and habitat quality, and examined trade-offs and synergies between them. Mixed-species forests were usually better in providing multiple EGS, although monocultures were often best for single EGS. The simulation results also demonstrated how changing environmental conditions along an elevational gradient had a strong impact on the structure of different species combinations and therefore on the provisioning of EGS. Tree species diversity alone is not a good predictor of multifunctionality. Mixtures should be selected based on local environmental conditions, complementary functional traits, and the ability to provide the EGS of interest. Although our work focused on current climatic conditions, we discuss how the modelling framework could be employed to consider the impacts of climate change and disturbances to improve our understanding of how mixed-species stands could be used to cope with these challenges.

Dense herbaceous understorey layers can impact tree regeneration and thereby affect forest succession. However, the implications of this interaction on large spatial and temporal scales are not well understood. To analyse the role of overstorey–understorey interactions for forest dynamics, we implemented an understorey layer (composed of the plant functional types grasses, forbs, ferns, herbs and shrubs) in the forest landscape model LandClim, focusing on competition for light as the main mode of interaction. The model was used to simulate post-disturbance dynamics over an elevational gradient of 560–2800 m a.s.l. in Central Europe. Simulation results showed strong impacts of the herbaceous understorey on tree regeneration within the first decades, but generally little effect on late-successional forests, i.e. not providing any evidence for ‘arrested’ succession. The results also demonstrated varying overstorey–understorey interactions across the landscape: strongest effects were found at low to mid elevations of the study landscapes, where tree establishment was substantially delayed. At high elevations, tree growth and establishment were more limited by low temperatures, and the effect of light competition from the understorey was negligible. Although the inclusion of large windthrow disturbances increased the biomass of herbaceous understorey across the landscape, this had only a small impact on the overstorey due to the presence of advance regeneration of trees. Overall, our results demonstrate that the herbaceous understorey can have a significant impact for forest landscape dynamics through light competition, and that non-woody plants should not be neglected in forest modelling.

Seed dispersal enables plants to reach hospitable germination sites and escape natural enemies. Understanding when and how much seed dispersal matters to plant fitness is critical for understanding plant population and community dynamics. At the same time, the complexity of factors that determine if a seed will be successfully dispersed and subsequently develop into a reproductive plant is daunting. Quantifying all factors that may influence seed dispersal effectiveness for any potential seed-vector relationship would require an unrealistically large amount of time, materials and financial resources. On the other hand, being able to make dispersal predictions is critical for predicting whether single species and entire ecosystems will be resilient to global change. Building on current frameworks, we here posit that seed dispersal ecology should adopt plant functional groups as analytical units to reduce this complexity to manageable levels. Functional groups can be used to distinguish, for their constituent species, whether it matters (i) if seeds are dispersed, (ii) into what context they are dispersed and (iii) what vectors disperse them. To avoid overgeneralization, we propose that the utility of these functional groups may be assessed by generating predictions based on the groups and then testing those predictions against species-specific data. We suggest that data collection and analysis can then be guided by robust functional group definitions. Generalizing across similar species in this way could help us to better understand the population and community dynamics of plants and tackle the complexity of seed dispersal as well as its disruption., Seed dispersal is critical to plant fitness and plant community dynamics. However, measuring and tracking all factors that influence seed dispersal effectiveness for any potential seed-disperser relationship would require an unrealistically large amount of time, materials and financial resources. Building on current frameworks, we suggest that seed dispersal ecology quantify seed dispersal at the scale of plant functional groups, in order to reduce complexity to manageable levels. Based on functional group classifications, plant species can be distinguished by their level of dependence on seed dispersal and its mechanisms.

As the single opportunity for plants to move, seed dispersal has an important impact on plant fitness, species distributions and patterns of biodiversity. However, models that predict dynamics such as risk of extinction, range shifts and biodiversity loss tend to rely on the mean value of parameters and rarely incorporate realistic dispersal mechanisms. By focusing on the mean population value, variation among individuals or variability caused by complex spatial and temporal dynamics is ignored. This calls for increased efforts to understand individual variation in dispersal and integrate it more explicitly into population and community models involving dispersal. However, the sources, magnitude and outcomes of intraspecific variation in dispersal are poorly characterized, limiting our understanding of the role of dispersal in mediating the dynamics of communities and their response to global change. In this manuscript, we synthesize recent research that examines the sources of individual variation in dispersal and emphasize its implications for plant fitness, populations and communities. We argue that this intraspecific variation in seed dispersal does not simply add noise to systems, but, in fact, alters dispersal processes and patterns with consequences for demography, communities, evolution and response to anthropogenic changes. We conclude with recommendations for moving this field of research forward., Seed dispersal—the single opportunity for plants to move—is important for plant fitness, species distributions and patterns of biodiversity. Models that predict extinction risk of species, range shifts and biodiversity tend to rely on average dispersal distances. However, we know that seed dispersal is highly variable even within a single species (e.g. some seeds go very far and some barely move away from their parent plant, some seeds end up in great quality habitats and some end up on roads). This paper looks at the consequences of this variation in seed dispersal for plants and their ability to respond to future global change.

Responses to future changes in climatic and socio-economic conditions can be expected to vary between sectors and regions, reflecting differential sensitivity to these highly uncertain factors. A sensitivity analysis was conducted using a suite of impact models (for health, agriculture, biodiversity, land use, floods and forestry) across Europe with respect to changes in key climate and socio-economic variables. Depending on the indicators, aggregated grid or indicative site results are reported for eight rectangular sub-regions that together span Europe from northern Finland to southern Spain and from western Ireland to the Baltic States and eastern Mediterranean, each plotted as scenario-neutral impact response surfaces (IRSs). These depict the modelled behaviour of an impact variable in response to changes in two key explanatory variables. To our knowledge, this is the first time the IRS approach has been applied to changes in socio-economic drivers and over such large regions. The British Isles region showed the smallest sensitivity to both temperature and precipitation, whereas Central Europe showed the strongest responses to temperature and Eastern Europe to precipitation. Across the regions, sensitivity to temperature was lowest for the two indicators of river discharge and highest for Norway spruce productivity. Sensitivity to precipitation was lowest for intensive agricultural land use, maize and potato yields and Scots pine productivity, and highest for Norway spruce productivity. Under future climate projections, North-eastern Europe showed increases in yields of all crops and productivity of all tree species, whereas Central and East Europe showed declines. River discharge indicators and forest productivity (except Holm oak) were projected to decline over southern European regions. Responses were more sensitive to socio-economic than to climate drivers for some impact indicators, as demonstrated for heat-related mortality, coastal flooding and land use. ISSN:1436-3798 ISSN:1436-378X

Severe drought events increasingly affect forests worldwide, but little is known about their long-term effects at the ecosystem level. Competition between trees and herbs (‘overstorey–understorey competition’) for soil water can reduce tree growth and regeneration success and may thereby alter forest structure and composition. However, these effects are typically ignored in modelling studies. To test the long-term impact of water competition by the herbaceous understorey on forest dynamics, we incorporated this process in the dynamic forest landscape model LandClim. Simulations were performed both with and without understorey under current and future climate scenarios (RCP4.5 and RCP8.5) in a drought-prone inner-Alpine valley in Switzerland. Under current climate, herbaceous understorey reduced tree regeneration biomass by up to 51%, particularly in drought-prone landscape positions (i.e., south-facing, low-elevation slopes), where it also caused a shift in forest composition towards drought-tolerant tree species (for example, Quercus pubescens). For adult trees, the understorey had a minor effect on growth. Under future climate change scenarios, increasing drought frequency and intensity resulted in large-scale mortality of canopy trees, which intensified the competitive interaction between the understorey and tree regeneration. At the driest landscape positions, a complete exclusion of tree regeneration and a shift towards an open, savannah-like vegetation occurred. Overall, our results demonstrate that water competition by the herbaceous understorey can cause long-lasting legacy effects on forest structure and composition across drought-prone landscapes, by affecting the vulnerable recruitment phase. Ignoring herbaceous vegetation may thus lead to a strong underestimation of future drought impacts on forests.

Aim It has been suggested that predicting species distributions requires a process-based and preferably dynamic approach. If dynamic models are to contribute towards understanding species distributions, uncertainties related to their spatial extrapolation and bioclimatic parameters need to be addressed. Here, we analyse the potential of a forest gap model for predicting species distributions. Location Pacific Northwest of North America (PNW). Methods We used the dynamic forest gap model ForClim, which includes climate, competition and demographic processes, to simulate the distribution of 18 tree species outside the domain of the data used for fitting. We explored model accuracy for species distributions at the regional scale by: (1) estimating species climatic tolerances so as to maximize agreement with regional distribution maps versus (2) employing a bioclimatic parameter set that produces high accuracy at the local scale. We then performed the opposite tests and simulated local forest composition in a small area in the PNW, using (3) the local bioclimatic parameters and (4) the bioclimatic parameters that produced the highest accuracy at the regional scale. We also compared the ForClim results with predictions from a standard correlative species distribution model (SDM). Results ForClim produced regional species distributions with fair to very good agreement for 12 tree species. The optimized bioclimatic parameters consistently improved the accuracy of regional predictions compared with simulations run with the local parameters, and were consistent with SDM results. At the local scale, predictions using the local parameters conformed to descriptions of forest composition, but accuracy decreased strongly when using the regionally calibrated parameters. Main conclusions Forest gap models can predict regional species distributions, but at the cost of reduced accuracy at the local scale. Future applications of gap models to understand regional species distributions should include robust parameterization schemes and additional ecological processes that are important at large spatial scales (e.g. dispersal, disturbances).

Aim According to the palynological record, rapid plant migrations following the retreat of the last glacier were common in North America and Europe. However, providing an explanation for these rapid migration rates has been challenging considering modern-day seed dispersal distances. We used the newly developed seed dispersal functionality in a hybrid dynamic global vegetation model (DGVM) to simulate two theories that have been proposed to explain rapid plant migrations: long-distance seed dispersal and northern refugial populations.

Regional vegetation-climate modelling studies have typically focused on boreal or temperate ecosystems in North America and Europe, almost completely overlooking tropical ecosystems. We present the first results of simulated regional vegetation-climate dynamics in Middle America as simulated by the model, LPJ-GUESS. The Kappa statistic indicated poor agreement, with a Kappa value of 0.301. When we modified the Kappa statistic by aggregating cell sizes and using generalized biomes, the Kappa value increased to 0.543, indicating a fair agreement. Total LAI simulated from LPJ-GUESS was strongly correlated to remotely sensed LAI values (r=0.75). Our simulations indicate that fire frequency was overestimated in tropical moist forests and underestimated in savannas. This underestimation of fire resulted in an over-simulation of dry tropical forest at the expense of savanna. We highlight additional reasons for the initially poor representation of vegetation in Middle America, including factors such as non-parameterized plant functional types (desert shrub, cacti, and other succulents), rugged topography, and an insufficient representation of soil.

Strong indirect effects are important in community and ecosystem processes, particularly in aquatic communities where predation and competition are the dominant processes. In this study, we examine an obligate pollination/seed predation mutualism between moths and yuccas and the balance of direct and indirect effects of ants, aphids, and cheater moths on this mutualism. Cheater moths (Tegeticula corruptrix) do not pollinate yuccas but oviposit into developing fruit, where their larvae consume yucca seeds. The overall effect of ants and aphids on yuccas was positive. Ants and aphids had no negative impact on the number of fruit retained per plant, and they had a positive effect on the average number of viable seeds per fruit. Yuccas with high ant and aphid densities had a 60% increase in viable, uneaten seeds. This increase in seed production was largely due to the negative interactions between ants and T. corruptrix. The reduction of cheater ovipositions saved yuccas almost 46 seeds per fruit, pl...

1. Although the moth–yucca mutualism is often studied as a pairwise interaction, yucca plants are also the sole host for a variety of other visitors. One of these additional visitors is a stem-boring moth, Prodoxus quinquepunctellus. 2. In this study, it is shown how the reproductive success of Prodoxus indirectly depends on the interactions between yuccas and their pollinators (Tegeticula, Prodoxidae) as well as the indirect effects of ants and aphids. 3. Aggressive wood ants foraging on yuccas will attack adult Prodoxus moths while attempting to oviposit. This reduces the number of eggs laid in yucca stalks, leading to fewer larvae feeding in the stalks. 4. Once in the stalk, the survival of Prodoxus eggs/larvae depends upon the rate at which the flowering stalks dry out during fruit maturation. Portions of the stalk above the highest fruit dry out quickly and survivorship approaches zero in these dry sections, while larvae in green sections of the flowering stalk have significantly higher survival rates. The presence of aphids feeding on the stalk slows down the rate of stalk drying and could lead to increased survival of Prodoxus larvae. 5. Overall, ants have strong indirect effects on P. quinquepunctellus by controlling how many eggs are laid in the stalk and by influencing the distribution of aphids. However, it is primarily the presence and position of the fruit that can affect larval survivorship, and fruit position is a function of pollinator visits and resource limitation. These complex interactions illustrate the importance of studying the yucca–moth mutualism in a community context.

Introduction Ecosystem goods and services (EGS) studies have had little impact on policy processes and real-world decision-making due to limited understanding of the interactions and feedbacks among ecological, social and economic processes. Here we present an inter- and transdisciplinary analysis of global change impacts on EGS provision in a European mountain region. Our aim is to evaluate the projected influence of ecological, economic and social drivers on future EGS provision and to show possible ways to address the predominant limitations of EGS studies. Methods The integrated findings from ecological experiments, mechanistic models of landscape dynamics, socio-economic land-use models, policy analysis and transdisciplinary stakeholder interactions are presented consecutively. Four regionally downscaled global change scenarios, for a case study region near Visp, Switzerland (350 km2), were used to examine the impacts of climate and socio-economic changes on four ecosystem services, i.e., food provision, timber production, net greenhouse gas emissions and protection from natural hazards. Results Our simulation results reveal four key aspects that influence the future provision of mountain EGS. First, we show the high spatial and temporal heterogeneity of EGS provision even in a small case study region. Second, we find that climate change impacts are much more pronounced for forest EGS, while changes to agricultural EGS result primarily from shifts in economic conditions. Third, our modeling results reveal the complex trade-offs associated with the different scenarios. Fourth, simulations illustrate the importance of interactions between environmental shifts and economic decisions. We discuss our simulation results with respect to both existing policy networks and transdisciplinary stakeholder interactions. Conclusion We describe a framework based on experiments and observations that effectively supports the integration of ecological processes into an integrative modeling chain of EGS provision in mountain regions, the political decision-making process and also transdisciplinary stakeholder interactions., Ecological processes, 3 (1), ISSN:2192-1709

Dynamic vegetation models (DVMs) follow a process‐based approach to simulate plant population demography, and have been used to address questions about disturbances, plant succession, community composition, and provisioning of ecosystem services under climate change scenarios. Despite their potential, they have seldom been used for studying species range dynamics explicitly. In this perspective paper, we make the case that DVMs should be used to this end and can improve our understanding of the factors that influence species range expansions and contractions. We review the benefits of using process‐based, dynamic models, emphasizing how DVMs can be applied specifically to questions about species range dynamics. Subsequently, we provide a critical evaluation of some of the limitations and trade‐offs associated with DVMs, and we use those to guide our discussions about future model development. This includes a discussion on which processes are lacking, specifically a mechanistic representation of dispersal, inclusion of the seedling stage, trait variability, and a dynamic representation of reproduction. We also discuss upscaling techniques that offer promising solutions for being able to run these models efficiently over large spatial extents. Our aim is to provide directions for future research efforts and to illustrate the value of the DVM approach. ISSN:0906-7590 ISSN:1600-0587

Background Most self-pollinating plants are annuals. According to the 'time-limitation' hypothesis, this association between selfing and the annual life cycle has evolved as a consequence of strong r-selection, involving severe time-limitation for completing the life cycle. Under this model, selection from frequent density-independent mortality in ephemeral habitats minimizes time to flower maturation, with selfing as a trade-off, and / or selection minimizes the time between flower maturation and ovule fertilization, in which case selfing has a direct fitness benefit. Predictions arising from this hypothesis were evaluated using phylogenetically-independent contrasts of several life history traits in predominantly selfing versus outcrossing annuals from a data base of 118 species distributed across 14 families. Data for life history traits specifically related to maturation and pollination times were obtained by monitoring the start and completion of different stages of reproductive development in a greenhouse study of selfing and outcrossing annuals from an unbiased sample of 25 species involving five pair-wise family comparisons and four pair-wise genus comparisons.