scholarly journals A 40-year evaluation of drivers of African rainforest change

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Colin A. Chapman ◽  
Carmen Galán-Acedo ◽  
Jan F. Gogarten ◽  
Rong Hou ◽  
Michael J. Lawes ◽  
...  
Keyword(s):  
Climate Change ◽  
Life History ◽  
Forest Dynamics ◽  
Stand Structure ◽  
Life History Strategies ◽  
Forest Composition ◽  
Maximum Temperature ◽  
Individual Species ◽  
Tree Community ◽  
Foraging Preferences

Abstract Background Tropical forests are repositories of much of the world’s biodiversity and are critical for mitigation of climate change. Yet, the drivers of forest dynamics are poorly understood. This is in large part due to the lack of long-term data on forest change and changes in drivers. Methodology We quantify changes in tree abundance, diversity, and stand structure along transects first enumerated in 1978 and resampled 2019 in Kibale National Park, Uganda. We tested five predictions. First, based on the purported role of seed dispersal and herbivory and our quantification of changes in the abundance of frugivores and herbivores, we tested two predictions of how faunal change could have influenced forest composition. Second, based on an evaluation of life history strategies, we tested two predictions concerning how the forest could have changed following disturbance that happened prior to written history. Finally, based on a 50-year climate record, we evaluate the possible influence of climate change on forest dynamics. Results More trees were present on the assessed transects in 2019 (508) than in 1978 (436), species richness remained similar, but diversity declined as the number of dominant species increased. Rainfall increased by only 3 mm over the 50 years but this had not significant effect on forest changes measured here. Annual average monthly maximum temperature increased significantly by 1.05 °C over 50 years. The abundance of frugivorous and folivorous primates and elephants increased over the 50 years of monitoring. Neither the prediction that an increase in abundance of seed dispersing frugivores increases the abundance of their preferred fruiting tree species, nor that as an increase in folivore abundance causes a decline in their preferred species were supported. As predicted, light-demanding species decreased in abundance while shade-tolerant species increased as expected from Kibale being disturbed prior to historical records. Finally, while temperature increased over the 50 years, we found no means to predict a priori how individual species would respond. Conclusions Our study revealed subtle changes in the tree community over 40 years, sizable increases in primate numbers, a substantial increase in the elephant population and an increase in local temperature. Yet, a clear picture of what set of interactions impact the change in the tree community remains elusive. Our data on tree life-history strategies and frugivore/herbivore foraging preferences suggest that trees species are under opposing pressures.

scholarly journals A 40-year Evaluation of Drivers of African Rainforest Change

2021 ◽  
Author(s):  
Colin Chapman ◽  
Carmen Galán-Acedo ◽  
Jan F. Gogarten ◽  
Rong Hou ◽  
Michael J. Lawes ◽  
...  
Keyword(s):  
Climate Change ◽  
Life History ◽  
Forest Dynamics ◽  
Stand Structure ◽  
Life History Strategies ◽  
Forest Composition ◽  
Maximum Temperature ◽  
Individual Species ◽  
Tree Community ◽  
Foraging Preferences

Abstract Background: Tropical forests are repositories of much of the world’s biodiversity and are critical for mitigation of climate change. Yet, the drivers of forest dynamics are poorly understood. This is in large part due to the lack of longitudinal data on forest change and changes in drivers.Methodology: We quantify changes in tree abundance, diversity, and stand structure along transects first enumerated in 1978 and resampled 2019 in Kibale National Park, Uganda. We tested five predictions. First, based on the purported role of seed dispersal and herbivory and our quantification of changes in the abundance of frugivores and herbivores, we tested two predictions of how faunal change could have influenced forest composition. Second, based on an evaluation of life history strategies, we tested two predictions concerning how the forest could have changed following disturbance that happened prior to written history. Finally, based on a 50-year climate record, we test the possible influence of climate change on forest dynamics. Results: More trees were present on the assessed transects in 2019 (508) than in 1978 (436), species richness remained similar, but diversity declined as the number of dominant species increased. Rainfall increased by only 3 mm over the 50 years but this effect was not significant. Annual average monthly maximum temperature increased significantly by 2.2°C over 50 years. The abundance of frugivorous and folivorous primates and elephants increased over the 50 years of monitoring. The predictions that as the abundance of seed dispersing frugivores increases the abundance of their preferred fruiting tree species would increases and that as the abundance of folivorous would cause a decline in their preferred species were both not supported. Since Kibale was disturbed prior to historical records, we predicted that light-demanding species would decrease in abundance, while shade-tolerant species would increase - this was supported. Finally, while temperature increased over the 50 years, we found no means to predict a priori how individual species would respond.Conclusions: Our study revealed subtle changes in the tree community over 40 years, sizable increases in primate numbers, a substantial increase in the elephant population and an increase in local temperature. Yet, a clear picture of what set of interactions impact the change in the tree community remains elusive. Our data on tree life-history strategies and frugivore/herbivore foraging preferences suggest that trees species are under opposing pressures.

scholarly journals Contrasting effects of climate change on seasonal survival of a hibernating mammal

2020 ◽  
Vol 117 (30) ◽  
pp. 18119-18126 ◽  
Author(s):  
Line S. Cordes ◽  
Daniel T. Blumstein ◽  
Kenneth B. Armitage ◽  
Paul J. CaraDonna ◽  
Dylan Z. Childs ◽  
...  
Keyword(s):  
Climate Change ◽  
Population Dynamics ◽  
Life History ◽  
Environmental Conditions ◽  
Temporal Trends ◽  
Life History Strategies ◽  
Environmental Drivers ◽  
Age Classes ◽  
History Of ◽  
Colorado Rocky Mountains

Seasonal environmental conditions shape the behavior and life history of virtually all organisms. Climate change is modifying these seasonal environmental conditions, which threatens to disrupt population dynamics. It is conceivable that climatic changes may be beneficial in one season but result in detrimental conditions in another because life-history strategies vary between these time periods. We analyzed the temporal trends in seasonal survival of yellow-bellied marmots (Marmota flaviventer) and explored the environmental drivers using a 40-y dataset from the Colorado Rocky Mountains (USA). Trends in survival revealed divergent seasonal patterns, which were similar across age-classes. Marmot survival declined during winter but generally increased during summer. Interestingly, different environmental factors appeared to drive survival trends across age-classes. Winter survival was largely driven by conditions during the preceding summer and the effect of continued climate change was likely to be mainly negative, whereas the likely outcome of continued climate change on summer survival was generally positive. This study illustrates that seasonal demographic responses need disentangling to accurately forecast the impacts of climate change on animal population dynamics.

scholarly journals Maturation in Atlantic salmon (Salmo salar, Salmonidae): a synthesis of ecological, genetic, and molecular processes

2021 ◽  
Author(s):  
Kenyon B. Mobley ◽  
Tutku Aykanat ◽  
Yann Czorlich ◽  
Andrew House ◽  
Johanna Kurko ◽  
...  
Keyword(s):  
Climate Change ◽  
Life History ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Economic Value ◽  
Life History Strategies ◽  
Life History Stages ◽  
Current State ◽  
Genomic Studies ◽  
Diversity Of Life

AbstractOver the past decades, Atlantic salmon (Salmo salar, Salmonidae) has emerged as a model system for sexual maturation research, owing to the high diversity of life history strategies, knowledge of trait genetic architecture, and their high economic value. The aim of this synthesis is to summarize the current state of knowledge concerning maturation in Atlantic salmon, outline knowledge gaps, and provide a roadmap for future work. We summarize the current state of knowledge: 1) maturation in Atlantic salmon takes place over the entire life cycle, starting as early as embryo development, 2) variation in the timing of maturation promotes diversity in life history strategies, 3) ecological and genetic factors influence maturation, 4) maturation processes are sex-specific and may have fitness consequences for each sex, 5) genomic studies have identified large-effect loci that influence maturation, 6) the brain-pituitary–gonadal axis regulates molecular and physiological processes of maturation, 7) maturation is a key component of fisheries, aquaculture, conservation, and management, and 8) climate change, fishing pressure, and other anthropogenic stressors likely have major effects on salmon maturation. In the future, maturation research should focus on a broader diversity of life history stages, including early embryonic development, the marine phase and return migration. We recommend studies combining ecological and genetic approaches will help disentangle the relative contributions of effects in different life history stages to maturation. Functional validation of large-effect loci should reveal how these genes influence maturation. Finally, continued research in maturation will improve our predictions concerning how salmon may adapt to fisheries, climate change, and other future challenges.

scholarly journals Climatic change and extinction risk of two globally threatened Ethiopian endemic bird species

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0249633
Author(s):  
Andrew J. Bladon ◽  
Paul F. Donald ◽  
Nigel J. Collar ◽  
Jarso Denge ◽  
Galgalo Dadacha ◽  
...  
Keyword(s):  
Climate Change ◽  
Captive Breeding ◽  
Extinction Risk ◽  
Bird Species ◽  
Maximum Temperature ◽  
Southern Ethiopia ◽  
Individual Species ◽  
Range Restriction ◽  
Risk Of Extinction ◽  
Modelling Approaches

Climate change is having profound effects on the distributions of species globally. Trait-based assessments predict that specialist and range-restricted species are among those most likely to be at risk of extinction from such changes. Understanding individual species’ responses to climate change is therefore critical for informing conservation planning. We use an established Species Distribution Modelling (SDM) protocol to describe the curious range-restriction of the globally threatened White-tailed Swallow (Hirundo megaensis) to a small area in southern Ethiopia. We find that, across a range of modelling approaches, the distribution of this species is well described by two climatic variables, maximum temperature and dry season precipitation. These same two variables have been previously found to limit the distribution of the unrelated but closely sympatric Ethiopian Bush-crow (Zavattariornis stresemanni). We project the future climatic suitability for both species under a range of climate scenarios and modelling approaches. Both species are at severe risk of extinction within the next half century, as the climate in 68–84% (for the swallow) and 90–100% (for the bush-crow) of their current ranges is predicted to become unsuitable. Intensive conservation measures, such as assisted migration and captive-breeding, may be the only options available to safeguard these two species. Their projected disappearance in the wild offers an opportunity to test the reliability of SDMs for predicting the fate of wild species. Monitoring future changes in the distribution and abundance of the bush-crow is particularly tractable because its nests are conspicuous and visible over large distances.

Life History Perspectives on Voltinism

2018 ◽  
pp. 125-150
Author(s):  
Carlos San Vicente
Keyword(s):  
Climate Change ◽  
Invasive Species ◽  
Life History ◽  
Population Ecology ◽  
Generation Time ◽  
Reproductive Investment ◽  
Life History Strategies ◽  
Biological Traits ◽  
Size At Maturity ◽  
Life Pattern

Patterns of voltinism are well documented in many crustaceans and other invetebrates, and these studies provide diverse insights into species biology, population ecology, and drivers of the evolution of voltinism. This chapter examines voltinism across crustacean taxa, with a focus on mysids as an informative model taxon that exhibits a broad range of life pattern diversity. Voltinism, which describes the number of generations per year for population or species, can be measured as generation time and is shaped by multiple environmental factors, including temperature, latitude, salinity, and depth. Generation time also varies with important biological traits, such as body size, life span, and maturation size and age. I discuss the relationships between voltinism and life history strategies, and the influence of voltinism on adaptative plasticity of species and their populations. Many factors shape evolution of voltinism, including fitness components such as survival, reproduction, and dispersal, as well as tradeoffs among age and size at maturity, reproductive investment, and lifespan. I highlight the importance of voltinism for population modeling in crustaceans, and for understanding regional differences in voltinism. Studies comparing and contrasting voltinism will be critical to better understand how climate change, strong habitat modifications, pollution, and invasive species will impact crustacean populations and their dependent communities.

scholarly journals Divergent Hydraulic Strategies Explain the Interspecific Associations of Co-Occurring Trees in Forest–Steppe Ecotone

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 942 ◽  
Author(s):  
Jingyu Dai ◽  
Hongyan Liu ◽  
Chongyang Xu ◽  
Yang Qi ◽  
Xinrong Zhu ◽  
...  
Keyword(s):  
Climate Change ◽  
Tree Species ◽  
Forest Dynamics ◽  
Physiological Mechanism ◽  
Forest Composition ◽  
Forest Plot ◽  
Forest Steppe ◽  
Interspecific Association ◽  
Early Stages ◽  
Interspecific Associations

Research Highlights: Answering how tree hydraulic strategies explain the interspecific associations of co-occurring trees in forest–steppe ecotone is an approach to link plant physiology to forest dynamics, and is helpful to predict forest composition and function changes with climate change. Background and Objectives: The forest–steppe ecotone—the driest edges of forest distribution—is continuously threatened by climate change. To predict the forest dynamics here, it is crucial to document the interspecific associations among existing trees and their potential physiological drivers. Materials and Methods: Forest–steppe ecotone is composed of forest and grassland patches in a mosaic pattern. We executed two years of complete quadrat surveys in a permanent forest plot in the ecotone in northern China, calculated the interspecific association among five main tree species and analyzed their hydraulic strategies, which are presented by combining leaf-specific hydraulic conductivity (Kl) and important thresholds on the stem-vulnerability curves. Results: No intensive competition was suggested among the co-occurring species, which can be explained by their divergent hydraulic strategies. The negative associations among Populus davidiana Dode and Betula platyphylla Suk., and P. davidiana and Betula dahurica Pall. can be explained as the result of their similar hydraulic strategies. Tilia mongolica Maxim. got a strong population development with its effective and safe hydraulic strategy. Generally, hydraulic-strategy differences can explain about 40% variations in interspecific association of species pairs. Oppositely, species sensitivity to early stages of drought is convergent in the forest. Conclusions: The divergent hydraulic strategies can partly explain the interspecific associations among tree species in forest–steppe ecotone and may be an important key for semiarid forests to keep stable. The convergent sensitivity to early stages of drought and the suckering regeneration strategy are also important for trees to survival. Our work revealing the physiological mechanism of forest compositions is a timely supplement to forest–steppe ecotone vegetation prediction.

scholarly journals Non-linear physiological responses to climate change: the case of Ceratitis capitata distribution and abundance in Europe

2021 ◽  
Author(s):  
Gianni Gilioli ◽  
Giorgio Sperandio ◽  
Michele Colturato ◽  
Sara Pasquali ◽  
Paola Gervasio ◽  
...  
Keyword(s):  
Climate Change ◽  
Life History ◽  
Ceratitis Capitata ◽  
Physiological Responses ◽  
Management Strategies ◽  
Fruit Fly ◽  
Life History Strategies ◽  
Modelling Framework ◽  
Non Linear ◽  
Climatic Scenarios

AbstractUnderstanding how climate change might influence the distribution and abundance of crop pests is fundamental for the development and the implementation of pest management strategies. Here we present and apply a modelling framework assessing the non-linear physiological responses of the life-history strategies of the Mediterranean fruit fly (Ceratitis capitata, Wiedemann) to temperature. The model is used to explore how climate change might influence the distribution and abundance of this pest in Europe. We estimated the change in the distribution, abundance and activity of this species under current (year 2020) and future (years 2030 and 2050) climatic scenarios. The effects of climate change on the distribution, abundance and activity of C. capitata are heterogeneous both in time and in space. A northward expansion of the species, an increase in the altitudinal limit marking the presence of the species, and an overall increase in population abundance is expected in areas that might become more suitable under a changing climate. On the contrary, stable or reduced population abundances can be expected in areas where climate change leads to equally suitable or less suitable conditions. This heterogeneity reflects the contribution of both spatial variability in the predicted climatic patterns and non-linearity in the responses of the species’ life-history strategies to temperature.

scholarly journals Plant communities as drivers of soil respiration: pathways, mechanisms, and significance for global change

2011 ◽  
Vol 8 (2) ◽  
pp. 2145-2181
Author(s):  
D. B. Metcalfe ◽  
R. A. Fisher ◽  
D. A. Wardle
Keyword(s):  
Climate Change ◽  
Plant Community ◽  
Plant Traits ◽  
Terrestrial Ecosystems ◽  
Ecosystem Processes ◽  
Life History Strategies ◽  
Individual Species ◽  
Individual Plant ◽  
Vegetation Types ◽  
Species Invasions

Abstract. Understanding the impacts of plant community characteristics on soil carbon dioxide efflux (R) is a key prerequisite for accurate prediction of the future carbon balance of terrestrial ecosystems under climate change. In this review, we synthesize relevant information from a wide spectrum of sources to evaluate the current state of knowledge about plant community effects on R, examine how this information is incorporated into global climate models, and highlight priorities for future research. Plant species consistently exhibit cohesive suites of traits, linked to contrasting life history strategies, which exert a variety of impacts on R. As such, we propose that plant community shifts towards dominance by fast growing plants with nutrient rich litter could provide a major, though often neglected, positive feedback to climate change. Within vegetation types, belowground carbon flux will mainly be controlled by photosynthesis, while amongst vegetation types this flux will be more dependent upon the specific characteristics of the plant life form. We also make the case that community composition, rather than diversity, is usually the dominant control on ecosystem processes in natural systems. Individual species impacts on R may be largest where the species accounts for most of the biomass in the ecosystem, has very distinct traits to the rest of the community, or modulates the occurrence of major natural disturbances. We show that climate-vegetation models incorporate a number of pathways whereby plants can affect R, but that simplifications regarding allocation schemes and drivers of litter decomposition may limit model accuracy. This situation could, however, be relatively easily improved with targeted experimental and field studies. Finally, we identify key gaps in knowledge and recommend them as priorities for future work. These include the patterns of photosynthate partitioning amongst belowground components, ecosystem level effects of individual plant traits, and the importance of trophic interactions and species invasions or extinctions for ecosystem processes. A final, overarching challenge is how to link these observations and drivers across spatio-temporal scales to predict regional or global changes in R over long time periods. A more unified approach to understanding R, which integrates information about plant traits and community dynamics, will be essential for better understanding, simulating and predicting feedbacks to R across terrestrial ecosystems and the earth-climate system.

Life History Variation and Phenology

2013 ◽  
Author(s):  
Eric Post
Keyword(s):  
Climate Change ◽  
Life History ◽  
Early Life History ◽  
Landscape Scale ◽  
Egg Laying ◽  
Life History Strategies ◽  
Life History Variation ◽  
Local Species ◽  
The Difference ◽  
Species Specific

This chapter looks at examples illustrating patterns in phenological responses to observed and experimental climate change. The most commonly observed phenological response to recent climate change is an advance in the timing of early life history events such as migration, plant emergence or flowering, amphibian breeding, or egg-laying dates in birds. Patterns in satellite-derived images of primary productivity suggest a lengthening of the plant-growing season in recent decades, whereas data on plant phenological dynamics from studies conducted at plot and sublandscape scales indicate shortened phenophases, or phenological events, in response to warming. This contrast may be resolved by recognizing the difference between phenology in the context of individual life history strategies of disparate species and landscape-scale patterns of phenology, and by recognizing the difference between local, species-specific phenological dynamics and those occurring at the landscape scale.

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