The effect of climate variables on sapwood anatomy of eucalyptus

This thesis considerably expands our understanding of hydraulic architecture in the genus Eucalyptus. The major finding is that xylem vessels in eucalypts taper at variable rates from the base of the stem to the top of the tree, depending on species and environment. The systematic assessment of changes in the structure of vessel tapering (reduction in xylem vessel diameter per unit length of stem, from the base to the apex) across a gradient of increasing aridity uncovers that the degree of taper is not a function of plant height but for coping with prevalent limitations like water or light. In some tall species from mesic climates (e.g. Eucalyptus regnans F. Muell.) vessel taper may be close to zero for the great majority of the stem, before increasing rapidly within the apical region of the canopy. For other species, such as those from semi-arid environments (e.g. Eucalyptus gracilis F. Muell.), tapering begins much further towards the base of the stem. These findings are highly novel and contradict some major theories (e.g. Metabolic Scaling Theory, MST). Yet, they are entirely in keeping with the general thrust of the ‘cohesion-tension’ theory of water movement in trees. This thesis includes several supporting studies for the above. A glasshouse study suggested thateven at seedling stage, environmental conditions such as temperature and moisture and nutrient availability, play roles in xylem formation (xylogenesis). Despite these suggestions, research in the glasshouse was inconclusive. This was most likely due to the relatively slow response of major biophysical processes, such as the development of structural entities like xylem vessels, when compared to faster responses to environmental conditions of biochemical processes such as those involved in photosynthesis and respiration. A field study of the potential role of water storage in heartwood (i.e. capacitance) in water transport, was hampered by prevailing environmental conditions and uncertainty around the sources of water being used by the study tree. Nonetheless, the data and the knowledge gained by both experiments add to current understanding how functionality of xylem tissues can be maintained under different environmental conditions, including elevated temperatures and water shortage. However, the major body of work in this thesis rests with analysis of xylem vessels at a microscopic scale. This work required significant development of techniques suitable for use with eucalypts that contain some of the hardest wood of all trees. The research also required development of software scripts capable of quantification of properties in large numbers (>150,000) of vessels across a dozen or so species, and multiple field sites. Additionally, the work reported here includes a rigorous assessment of climate across field sites and then use of that to interpret xylem structure. The resultant phase analysis of rates of tapering within trees, is both an Australian and world first. Adopting methodology widely used in other fields of biology, this thesis employs a phase analysis of tapering of xylem vessels to highlight: 1. That the insertion point of vessel taper towards the top of trees differs largely among eucalypt species. 2. That regardless of species and location, vessel diameter at the apex does not differ widely among species – this, at least, accords with MST. 3. That rates of taper within the apical region of canopies where the risk of cavitation is greatest are closely related to environmental conditions, particularly the availability of water and competition for light

The effect of climate variables on sapwood anatomy of eucalyptus

This thesis considerably expands our understanding of hydraulic architecture in the genus Eucalyptus. The major finding is that xylem vessels in eucalypts taper at variable rates from the base of the stem to the top of the tree, depending on species and environment. The systematic assessment of changes in the structure of vessel tapering (reduction in xylem vessel diameter per unit length of stem, from the base to the apex) across a gradient of increasing aridity uncovers that the degree of taper is not a function of plant height but for coping with prevalent limitations like water or light. In some tall species from mesic climates (e.g. Eucalyptus regnans F. Muell.) vessel taper may be close to zero for the great majority of the stem, before increasing rapidly within the apical region of the canopy. For other species, such as those from semi-arid environments (e.g. Eucalyptus gracilis F. Muell.), tapering begins much further towards the base of the stem. These findings are highly novel and contradict some major theories (e.g. Metabolic Scaling Theory, MST). Yet, they are entirely in keeping with the general thrust of the ‘cohesion-tension’ theory of water movement in trees. This thesis includes several supporting studies for the above. A glasshouse study suggested thateven at seedling stage, environmental conditions such as temperature and moisture and nutrient availability, play roles in xylem formation (xylogenesis). Despite these suggestions, research in the glasshouse was inconclusive. This was most likely due to the relatively slow response of major biophysical processes, such as the development of structural entities like xylem vessels, when compared to faster responses to environmental conditions of biochemical processes such as those involved in photosynthesis and respiration. A field study of the potential role of water storage in heartwood (i.e. capacitance) in water transport, was hampered by prevailing environmental conditions and uncertainty around the sources of water being used by the study tree. Nonetheless, the data and the knowledge gained by both experiments add to current understanding how functionality of xylem tissues can be maintained under different environmental conditions, including elevated temperatures and water shortage. However, the major body of work in this thesis rests with analysis of xylem vessels at a microscopic scale. This work required significant development of techniques suitable for use with eucalypts that contain some of the hardest wood of all trees. The research also required development of software scripts capable of quantification of properties in large numbers (>150,000) of vessels across a dozen or so species, and multiple field sites. Additionally, the work reported here includes a rigorous assessment of climate across field sites and then use of that to interpret xylem structure. The resultant phase analysis of rates of tapering within trees, is both an Australian and world first. Adopting methodology widely used in other fields of biology, this thesis employs a phase analysis of tapering of xylem vessels to highlight: 1. That the insertion point of vessel taper towards the top of trees differs largely among eucalypt species. 2. That regardless of species and location, vessel diameter at the apex does not differ widely among species – this, at least, accords with MST. 3. That rates of taper within the apical region of canopies where the risk of cavitation is greatest are closely related to environmental conditions, particularly the availability of water and competition for light

Carbon Sequestration and Carbon Stock of Agroforestry Tree Species Around Cyamudongo Isolated Rain Forest and Arboretum of Ruhande, Rwanda

Agroforestry (AF) is widely considered the most important tool to mitigate climate change-related issues by removing Carbon (C) Dioxide (CO2) from the atmosphere and storing C. Therefore, this study aims to broaden current knowledge on the impact of sustainable Agroforestry (AF) on the C sequestration rate and C stock in the surroundings of Cyamudongo isolated rain forest and Ruhande Arboretum. To understand this, the permanent sample plots (PSPs) were established mainly in the four designed transects of four km long originating on the Cyamudongo isolated rain forest boundary following the slope gradient ranging from 1286 to 2015 m asl. A total number of 73 PSPs were established in the Cyamudongo study area while 3 PSPs were established in the Ruhande AF plot. The Arc Map GIS 10.4 was used to design and map the sampling areas while GPS was used for the localization of the plots. Statistical significance was analyzed through R-software. The estimated quantity of sequestrated C for 2 years and 34 years of AF species was 13.11 t C ha -1 yr-1 (equivalent to 48 t CO2 ha -1 yr-1) and 6.85 t ha-1 yr-1 (equivalent to 25.1 t CO2 ha -1 yr-1) in Cyamudongo and Ruhande respectively. The estimated quantity of C stored by the Ruhande AF plot is 232.94 t ha-1. In Cyamudongo, the overall C stored by the AF systems was 823 t ha-1 by both young tree species established by the Cyamudongo Project (35.84 t ha-1) and C stored by existing AF species before the existence of the Project (787.12 t ha-1). In all study areas, the Grevillea robusta contributed more to overall stored C. The correlation coefficients between tree diameter and living biomass ranged from moderate to very strong due to differences in terms of age, stage of growth, and tree species

Resource manipulation reveals interactive phenotype-dependent foraging in free-ranging lizards

<p>Recent evidence suggests that individuals differ in foraging tactics and this variation is often linked to an individual's behavioural type (BT). Yet, while foraging typically comprises a series of search and handling steps, empirical investigations have rarely considered BT-dependent effects across multiple stages of the foraging process, particularly in natural settings.</p> <p>In our long-term sleepy lizard (Tiliqua rugosa) study system, individuals exhibit behavioural consistency in boldness (measured as an individual's willingness to approach a novel food item in the presence of a threat) and aggressiveness (measured as an individual's response to an 'attack' by a conspecific dummy). These BTs are only weakly correlated and have previously been shown to have interactive effects on lizard space use and movement, suggesting that they could also affect lizard foraging performance, particularly in their search behaviour for food.</p> <p>To investigate how lizards' BTs affect their foraging process in the wild, we supplemented food in 123 patches across a 120-ha study site with three food abundance treatments (high, low, and no-food-controls). Patches were replenished twice a week over the species' entire spring activity season and feeding behaviours were quantified with camera traps at these patches. We tracked lizards using GPS to determine their home range (HR) size and repeatedly assayed their aggressiveness and boldness in designated assays.</p> <p>We hypothesised that bolder lizards would be more efficient foragers while aggressive ones would be less attentive to the quality of foraging patches. We found an interactive BT effect on overall foraging performance. Individuals that were both bold and aggressive ate the highest number of food items from the foraging array. Further dissection of the foraging process showed that aggressive lizards in general ate the fewest food items in part because they visited foraging patches less regularly, and because they discriminated less between high and low-quality patches when revisiting them. Bolder lizards, in contrast, ate more tomatoes because they visited foraging patches more regularly, and ate a higher proportion of the available tomatoes at patches during visits.</p> <p>Our study demonstrates that BTs can interact to affect different search and handling components of the foraging process, leading to within-population variation in foraging success. Given that individual differences in foraging and movement will influence social and ecological interactions, our results highlight the potential role of BT's in shaping individual fitness strategies and population dynamics.</p><p>Funding provided by: National Science Foundation<br>ROR ID: https://ror.org/021nxhr62<br>Award Number: 1456730</p><p>The data included in this manusript combines several sources of information from our field site at Bundy Bore, Australia.</p> <ol> <li>The most central dataset for this paper is the lizard visit documentation, obtained by camera-traps recording in a time-lapse mode, the dataset is included here in a cleaned form, after removing irrelevant lines (e.g. non lizard visit) and colunms. </li> <li>Behavioral data with repeated assays on individual lizards. This data is included in the recent paper by Payne et al. (2021) Animal Behaviour; as well as in the dataset cited below.</li> <li>GPS tracking data for estimating Home Range (HR) size for focal lizards. This is used as a predictor in relevant models. HR . Information on the HR results is aviaible in the included dataset and a broader version that includs several years and not only this particualr one was included in Payne et al. (2022) Ecological Monographs</li> <li>Code for the modeling is included as well, see readme for more details.  </li> </ol&gt

Resource manipulation reveals interactive phenotype-dependent foraging in free-ranging lizards

<p>Recent evidence suggests that individuals differ in foraging tactics and this variation is often linked to an individual's behavioural type (BT). Yet, while foraging typically comprises a series of search and handling steps, empirical investigations have rarely considered BT-dependent effects across multiple stages of the foraging process, particularly in natural settings.</p> <p>In our long-term sleepy lizard (Tiliqua rugosa) study system, individuals exhibit behavioural consistency in boldness (measured as an individual's willingness to approach a novel food item in the presence of a threat) and aggressiveness (measured as an individual's response to an 'attack' by a conspecific dummy). These BTs are only weakly correlated and have previously been shown to have interactive effects on lizard space use and movement, suggesting that they could also affect lizard foraging performance, particularly in their search behaviour for food.</p> <p>To investigate how lizards' BTs affect their foraging process in the wild, we supplemented food in 123 patches across a 120-ha study site with three food abundance treatments (high, low, and no-food-controls). Patches were replenished twice a week over the species' entire spring activity season and feeding behaviours were quantified with camera traps at these patches. We tracked lizards using GPS to determine their home range (HR) size and repeatedly assayed their aggressiveness and boldness in designated assays.</p> <p>We hypothesised that bolder lizards would be more efficient foragers while aggressive ones would be less attentive to the quality of foraging patches. We found an interactive BT effect on overall foraging performance. Individuals that were both bold and aggressive ate the highest number of food items from the foraging array. Further dissection of the foraging process showed that aggressive lizards in general ate the fewest food items in part because they visited foraging patches less regularly, and because they discriminated less between high and low-quality patches when revisiting them. Bolder lizards, in contrast, ate more tomatoes because they visited foraging patches more regularly, and ate a higher proportion of the available tomatoes at patches during visits.</p> <p>Our study demonstrates that BTs can interact to affect different search and handling components of the foraging process, leading to within-population variation in foraging success. Given that individual differences in foraging and movement will influence social and ecological interactions, our results highlight the potential role of BT's in shaping individual fitness strategies and population dynamics.</p><p>Funding provided by: National Science Foundation<br>ROR ID: https://ror.org/021nxhr62<br>Award Number: 1456730</p><p>The data included in this manusript combines several sources of information from our field site at Bundy Bore, Australia.</p> <ol> <li>The most central dataset for this paper is the lizard visit documentation, obtained by camera-traps recording in a time-lapse mode, the dataset is included here in a cleaned form, after removing irrelevant lines (e.g. non lizard visit) and colunms. </li> <li>Behavioral data with repeated assays on individual lizards. This data is included in the recent paper by Payne et al. (2021) Animal Behaviour; as well as in the dataset cited below.</li> <li>GPS tracking data for estimating Home Range (HR) size for focal lizards. This is used as a predictor in relevant models. HR . Information on the HR results is aviaible in the included dataset and a broader version that includs several years and not only this particualr one was included in Payne et al. (2022) Ecological Monographs</li> <li>Code for the modeling is included as well, see readme for more details.  </li> </ol&gt

Carbon Sequestration and Carbon Stock of Agroforestry Tree Species Around Cyamudongo Isolated Rain Forest and Arboretum of Ruhande, Rwanda

Agroforestry (AF) is widely considered the most important tool to mitigate climate change-related issues by removing Carbon (C) Dioxide (CO2) from the atmosphere and storing C. Therefore, this study aims to broaden current knowledge on the impact of sustainable Agroforestry (AF) on the C sequestration rate and C stock in the surroundings of Cyamudongo isolated rain forest and Ruhande Arboretum. To understand this, the permanent sample plots (PSPs) were established mainly in the four designed transects of four km long originating on the Cyamudongo isolated rain forest boundary following the slope gradient ranging from 1286 to 2015 m asl. A total number of 73 PSPs were established in the Cyamudongo study area while 3 PSPs were established in the Ruhande AF plot. The Arc Map GIS 10.4 was used to design and map the sampling areas while GPS was used for the localization of the plots. Statistical significance was analyzed through R-software. The estimated quantity of sequestrated C for 2 years and 34 years of AF species was 13.11 t C ha -1 yr-1 (equivalent to 48 t CO2 ha -1 yr-1) and 6.85 t ha-1 yr-1 (equivalent to 25.1 t CO2 ha -1 yr-1) in Cyamudongo and Ruhande respectively. The estimated quantity of C stored by the Ruhande AF plot is 232.94 t ha-1. In Cyamudongo, the overall C stored by the AF systems was 823 t ha-1 by both young tree species established by the Cyamudongo Project (35.84 t ha-1) and C stored by existing AF species before the existence of the Project (787.12 t ha-1). In all study areas, the Grevillea robusta contributed more to overall stored C. The correlation coefficients between tree diameter and living biomass ranged from moderate to very strong due to differences in terms of age, stage of growth, and tree species.</jats:p

Resource manipulation reveals interactive phenotype‐dependent foraging in free‐ranging lizards

Abstract Recent evidence suggests that individuals differ in foraging tactics and this variation is often linked to an individual's behavioural type (BT). Yet, while foraging typically comprises a series of search and handling steps, empirical investigations have rarely considered BT‐dependent effects across multiple stages of the foraging process, particularly in natural settings. In our long‐term sleepy lizard ( Tiliqua rugosa ) study system, individuals exhibit behavioural consistency in boldness (measured as an individual's willingness to approach a novel food item in the presence of a threat) and aggressiveness (measured as an individual's response to an ‘attack’ by a conspecific dummy). These BTs are only weakly correlated and have previously been shown to have interactive effects on lizard space use and movement, suggesting that they could also affect lizard foraging performance, particularly in their search behaviour for food. To investigate how lizards' BTs affect their foraging process in the wild, we supplemented food in 123 patches across a 120‐ha study site with three food abundance treatments (high, low and no‐food controls). Patches were replenished twice a week over the species' entire spring activity season and feeding behaviours were quantified with camera traps at these patches. We tracked lizards using GPS to determine their home range (HR) size and repeatedly assayed their aggressiveness and boldness in designated assays. We hypothesised that bolder lizards would be more efficient foragers while aggressive ones would be less attentive to the quality of foraging patches. We found an interactive BT effect on overall foraging performance. Individuals that were both bold and aggressive ate the highest number of food items from the foraging array. Further dissection of the foraging process showed that aggressive lizards in general ate the fewest food items in part because they visited foraging patches less regularly, and because they discriminated less between high and low‐quality patches when revisiting them. Bolder lizards, in contrast, ate more tomatoes because they visited foraging patches more regularly, and ate a higher proportion of the available tomatoes at patches during visits. Our study demonstrates that BTs can interact to affect different search and handling components of the foraging process, leading to within‐population variation in foraging success. Given that individual differences in foraging and movement will influence social and ecological interactions, our results highlight the potential role of BT's in shaping individual fitness strategies and population dynamics.National Science Foundation https://doi.org/10.13039/100000001Svenska Forskningsrådet Formas https://doi.org/10.13039/501100001862Israel Science Foundation https://doi.org/10.13039/50110000397

Climate determines vascular traits in the ecologically diverse genus Eucalyptus

Current theory presumes that natural selection on vascular traits is controlled by a trade-off between efficiency and safety of hydraulic architecture. Hence, traits linked to efficiency, such as vessel diameter, should show biogeographic patterns; but critical tests of these predictions are rare, largely owing to confounding effects of environment, tree size and phylogeny. Using wood sampled from a phylogenetically constrained set of 28 Eucalyptus species, collected from a wide gradient of aridity across Australia, we show that hydraulic architecture reflects adaptive radiation of this genus in response to variation in climate. With increasing aridity, vessel diameters narrow, their frequency increases with a distribution that becomes gradually positively skewed and sapwood density increases while the theoretical hydraulic conductivity declines. Differences in these hydraulic traits appear largely genotypic in origin rather than environmentally plastic. Data reported here reflect long-term adaptation of hydraulic architecture to water availability. Rapidly changing climates, on the other hand, present significant challenges to the ability of eucalypts to adapt their vasculature

Vessel diameter and related hydraulic traits of 31 Eucalyptus species arrayed along a gradient of water availability

Theory predicts a trade-off between efficiency and safety of water transport in trees (e.g. Tyree and Zimmermann, 2002; Sperry et al., 2008; Meinzer et al., 2010), manifested through changes in tree hydraulic architecture. It is widely observed that average diameters of xylem vessels gradually narrow with decreasing water availability (Carlquist, 2012; Pfautsch et al., 2016). The associated trade-off with narrowing vessel diameter – despite at a higher frequency – is reduced rates of transpiration, lower stomatal conductance and consequently lower foliar uptake of atmospheric CO2 (Santiago et al., 2004; Poorter et al. 2009). Sapwood in such trees is likely to be dense (Chave et al., 2009), arguably due to greater investment in fibre wall thickness that provides increased mechanical strength against the collapse of vessels under high negative pressures (Poorter et al. 2009). Hence, while sapwood of trees in arid environments would consist mostly of narrow vessels, one would expect the hydraulic architecture of trees in mesic environments to feature fewer but wider vessels so as to transport larger quantities of water. This would in turn support high rates of stomatal conductance and uptake of CO2, which fuels rapid growth when synthesizing low-density sapwood (Poorter et al. 2009)

JUN mediates the senescence associated secretory phenotype and immune cell recruitment to prevent prostate cancer progression

Background: Prostate cancer develops through malignant transformation of the prostate epithelium in a stepwise, mutation-driven process. Although activator protein-1 transcription factors such as JUN have been implicated as potential oncogenic drivers, the molecular programs contributing to prostate cancer progression are not fully understood. Methods: We analyzed JUN expression in clinical prostate cancer samples across different stages and investigated its functional role in a Pten-deficient mouse model. We performed histopathological examinations, transcriptomic analyses and explored the senescence-associated secretory phenotype in the tumor microenvironment. Results: Elevated JUN levels characterized early-stage prostate cancer and predicted improved survival in human and murine samples. Immune-phenotyping of Pten-deficient prostates revealed high accumulation of tumor-infiltrating leukocytes, particularly innate immune cells, neutrophils and macrophages as well as high levels of STAT3 activation and IL-1β production. Jun depletion in a Pten-deficient background prevented immune cell attraction which was accompanied by significant reduction of active STAT3 and IL-1β and accelerated prostate tumor growth. Comparative transcriptome profiling of prostate epithelial cells revealed a senescence-associated gene signature, upregulation of pro-inflammatory processes involved in immune cell attraction and of chemokines such as IL-1β, TNF-α, CCL3 and CCL8 in Pten-deficient prostates. Strikingly, JUN depletion reversed both the senescence-associated secretory phenotype and senescence-associated immune cell infiltration but had no impact on cell cycle arrest. As a result, JUN depletion in Pten-deficient prostates interfered with the senescence-associated immune clearance and accelerated tumor growth. Conclusions: Our results suggest that JUN acts as tumor-suppressor and decelerates the progression of prostate cancer by transcriptional regulation of senescence- and inflammation-associated genes. This study opens avenues for novel treatment strategies that could impede disease progression and improve patient outcomes. Graphical Abstract: (Figure presented.)