For many species, distribution and abundance is driven by a trade-off between abiotic and biotic stress tolerance (i.e. physical stress versus competition or predation stress). This trade- off may be caused by metabolic rate differences in species such that slow metabolic rates increase abiotic tolerance but decrease biotic tolerance. I investigated how metabolic rate differences were responsible for an abiotic-biotic tolerance trade-off in brown mudfish (Neochanna apoda) and banded kokopu (Galaxias fasciatus), that drives the allopatric distribution of these fish in podocarp swamp-forest pools. Brown mudfish and banded kokopu distribution across 65 forest pools in Saltwater forest, Westland National Park, New Zealand was almost completely allopatric. Mudfish were restricted to pools with extreme abiotic stress including hypoxia, acidity and droughts because of kokopu predation in benign pools. This meant the mudfish realised niche was only a small fraction of their large fundamental niche, which was the largest out of sixteen freshwater fish species surveyed in South Island West Coast habitats. Thus mudfish had a large fundamental to realised niche ratio because of strong physiological stress tolerance but poor biotic stress tolerance compared to other fish. A low metabolic capacity in mudfish compared to kokopu in terms of resting and maximum metabolic rates and aerobic scope explained the strong mudfish tolerance to extreme abiotic stress, but also their sensitivity to biotic stress by more powerful kokopu in benign pools, and hence their allopatric distribution with kokopu. Despite being restricted to extreme physical stress, mudfish populations were, in fact, more dense than those of kokopu, because of low individual mudfish resting metabolic rates, which would cause resources to be divided over more individuals. Distribution and abundance in mudfish and kokopu were therefore driven by an abiotic-biotic tolerance trade-off caused by a physiological trade-off between having slow or fast metabolic rates, respectively. The negative relationship between species resting metabolic rates and their tolerance to abiotic stress provides a way of estimating the impact of human induced environmental change that can either increase or decrease habitat harshness. Thus species with low metabolic rates, like mudfish, will be negatively affected by human induced environmental change that removes abiotic habitat stress and replaces it with benign conditions. My evidence shows that extreme stressors provide a protective habitat supporting high mudfish biomass with significant conservation value that should be maintained for the long-term persistence of mudfish populations.

A knowledge of the allometry of algal growth and respiration can be applied to biomass-size distribution models which are in turn used in the prediction of fish yield and ecosystem studies. However, the scaling exponents reported in the literature are variable. This variation may be attributed to differences in the expression of cell size and phylogeny, but could also reflect small sample size which underlie most published regressions. This thesis establishes the allometry of algal growth and respiration based on a larger sample taken from the literature, and evaluates the effects of differences in gross taxonomy and in the expression of cell size on these relations. Allometric relations based on cell carbon appear more consistent with relations from other taxa than those based on cell volume, reflecting the size dependence of algal elemental composition which does not occur in most other taxa. The allometric relation of algal respiration (R in pl O$ rm sb2 cdot cell sp{-1} cdot hr sp{-1})$ was found to be R = 0.030C$ sp{0.93}$ where C is cell carbon content in pg C$ rm cdot cell sp{-1}$. Among the 6 divisions studied (Chlorophyta, Chrysophyta, Cyanophyta, Euglenophyta, Pyrrophyta, Rhodophyta), chlorophytes, euglenophytes and rhodophytes exhibited different respiration-size relation but separate relations were not developed for each of those groups due to patterns in residuals or small sample sizes. The specific rate of algal growth ($ mu$ in divisions$ cdot$day$ sp{-1}$) also depends on size and it is found to be $ mu$ = 3.45C$ sp{-0.21}.$ All taxa studied here (Chlorophyta, Chrysophyta, Pyrrophyta) have similar scaling exponents for growth but Pyrrophyta have significantly lower growth rates than other algae of similar size.

Thesis (M.S.)--Ohio University, March, 2008. / Title from PDF t.p. Includes bibliographical references.

Thesis (Ph. D.)--Duke University, 2007. / Includes bibliographical references.

Orientador: Izabelle Auxiliadora Molina de Almeida Teixeira / Coorientador: Normand Roger St-Pierre / Banca: Polyana Pizzi Rotta Costa e Silva / Banca: Mário Luiz Chizzotti / Banca: Márcia Helena Machado da Rocha Fernandes / Banca: Kleber Tomas de Resende / Resumo: Um banco de dados de sete estudos de abate comparativo utilizando caprinos Saanen foi construído para predizer as exigências de proteína e energia para mantença e crescimento de caprinos leiteiros. Para a avaliação da utilização de energia por caprinos leiteiros foram utilizados 238 caprinos Saanen submetidos a três níveis alimentação. O delineamento experimental proporcionou variação no consumo de energia metabolizável (CEM) e peso corporal (PC), permitindo o desenvolvimento de equações de regressão para predição das exigências líquidas de energia para mantença (ELM). A relação não linear entre CEM e produção de calor foi utilizada para estimativa das exigências de ELM e as exigências de energia metabolizável para mantença (EMM), a eficiência de uso de energia para mantença (km) foi calculada como a relação entre ELM e EMM. O coeficiente de inclinação entre a energia retida (ER) em relação ao consumo de energia metabolizável acima da mantença (CEMG) foi adotado como a eficiência de utilização de EM para crescimento (kg). A eficiência de utilização de EM para retenção de proteína (kp) e gordura (kf) foram calculadas utilizando uma regressão múltipla do CEMG (modelo com intercepto igual a 0) na ER como proteína e na ER como gordura. Para o desenvolvimento das equações lineares foi utilizado o PROC MIXED e para as não lineares o PROC NLINMIXED do software SAS considerando a classe sexual (macho castrado, macho inteiro e fêmea; 80, 98, e 60, respectivamente) como efeito fixo e b... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: A database of seven comparative slaughter studies of Saanen goats was gathered to predict the protein and energy requirements for maintenance and growth of dairy goats. For the evaluation of energy utilization by dairy goats we used 238 Saanen goats subjected to three levels of intake. The experimental design provided different levels of metabolizable energy intake (MEI) and body weight (BW), allowing the development of regression equations to predict the net energy requirements for maintenance (NEM). The nonlinear relationship between MEI and heat production was used to estimate the NEM and the requirements of ME for maintenance (MEM). The efficiency of energy utilization for maintenance (km) was calculated as the relationship between NEM and MEM. The slope between retained energy (RE) and metabolizable energy intake above maintenance (MEIG) was adopted as the efficiency of utilization of ME for growth (kg). The efficiency of utilization of energy for protein and fat deposition (kp and kf, respectively) were calculated using a multiple regression on MEIG (model intercept equal to 0) on the RE as protein (REp) and RE as fat (REf). For the development of linear and non-linear equations we used MIXED and NLMIXED procedures in SAS considering sex (castrated male, intact male, and female, n = 80, 98, and 60, respectively) as fixed effect and block nested in study and sex as random effect. The NEM was affected by sex where castrated males and intact males have similar requirements (75 kcal/kg0.75 empty BW); on the other hand, females presented a lower value (64 kcal/kg0.75 empty BW). The km did not differ between sexes (0.62). The kg was different between sexes (0.32 for castrated males, 0.26 for intact males, and 0.31 for females) but the kp (0.21) and kf (0.80) were similar between sexes. For the evalu... (Complete abstract click electronic access below) / Doutor

A herbochronological study was conducted in the dry Himalayas. The study was focused on allometric relationships in four populations of Potentilla pamirica.The population were situated in four different altitudes.

The effectiveness of giant cane [Arundinaria gigantea(Walt.) Muhl.] as riparian buffer vegetation has been demonstrated through research and has gained interest from state and federal agencies to support restoration efforts. Unfortunately, little is known about the physical and chemical properties of the soils below canebrakes and how soil characteristics influence aboveground and belowground biomass production. To determine what physical attributes of the plant influence its success as riparian buffer vegetation and also to determine the interactions with underlying soils, fourteen canebrakes were sampled throughout Southern Illinois. Objective one was to develop an allometric equation to quantify belowground biomass based on aboveground parameters of canebrakes. Previous research found that successful propagation was dependent on rhizome length, the number of internodes and the number of rhizome buds present, but no data exists regarding the yield of rhizomes for a given area. By harvesting all aboveground biomass (culms and leaves) and belowground biomass (roots and rhizomes) to a depth of 25 cm from a 1-m2 plot at each site, morphometric characteristics were quantified and biomass allocation throughout the plant was determined. A significant linear relationship between total aboveground biomass (live and dead) and belowground biomass in giant cane was evident (R=0.865, p<0.001). Although this is a strong relationship, it may be impractical for a manager to harvest, process, and weigh all of the aboveground biomass to speculate the biomass below ground. Therefore, metrics were explored for predicting the length of rhizome, number of rhizome internodes and number of rhizome buds an area will yield using multiple regression and models were developed that estimate these parameters. Using the equation that predicts the number of rhizome buds for a given area, the yield of propagules can then be estimated. Although this equation does not account for all variation of belowground characteristics, it will provide a general guideline for land managers restoring giant cane. The second objective was to estimate biomass allocation of giant cane roots/rhizomes beneath canebrakes by depth (i.e., at 25-cm increments to a depth of 150 cm). Results showed that 67% of giant cane's belowground biomass was within the top 25 cm of the soil profile and accounted for 65% of all belowground biomass encountered at that depth. Giant cane rhizomes were documented to a depth of 51-75 cm deep while cane roots existed in the deepest cores at a depth of 126-150 cm with an average density of 0.08 kg m-3. Giant cane belowground biomass declined with increasing depth, but was still the dominant species at 26-50 cm, comprising 61% of all biomass encountered at that depth. These results support the utility of giant cane as an effective riparian buffer species by increasing the soil porosity and promoting infiltration while contributing a significant source of carbon to the soil profile. Chemical and physical soil properties were measured to determine if they related to canebrake characteristics. Significant correlations were found between various soil properties and canebrake characteristics, implying there is an interaction between giant cane and the underlying soil. Results from this research will improve our understanding of the dynamics of giant cane and supplement existing information to help guide restoration efforts.

The limb skeleton of tapirs (Perissodactyla: Tapirus spp.) was traditionally thought to exhibit morphological variation only as a result of changes in body size. Here, we test whether forelimb variation exhibited by Tapirus is solely an artefact of size fluctuations through the tapir fossil record or whether it is influenced by habitat differences. We investigated the forelimb osteology of 12 species of Tapirus using three-dimensional geometric morphometrics on laser surface scans. Aligned shape coordinates were regressed against intrinsic bone size to account for allometry. Taxa of equivalent body mass exhibited significant differences in size-corrected bone shape. Stable carbon isotope values were averaged per species as a proxy for habitat density. Multivariate regressions of the humerus, pisiform, cuneiform, unciform, third and fourth metacarpals revealed no significant influence of size on shape. The lateral carpals (pisiform, cuneiform, unciform) demonstrated variation across the habitat density gradient. Observed variation is likely driven by species in the extinct subgenus Helicotapirus tapirs, which inhabited drier, more open woodland than modern taxa. We conclude that tapir forelimb variation is not exclusively an artefact of body size, with lateral wrist bones displaying notable differences across a habitat density gradient, beyond that resulting from size and phylogenetic effects.

More than 20 million clonal loblolly pines have been planted throughout the southeastern United States. Fertilizer has been applied to more than 6.5 million hectares of plantations to alleviate deficiencies of nitrogen and phosphorus that limit growth. Because cloning loblolly pine in large numbers has only become possible in the last decade, it is unknown how clones may respond differently to fertilizer application. Growth, growth efficiency, and biomass partitioning responses to fertilizer application were investigated among 25 clones planted in the Virginia Piedmont. Closely related clones varied in their fertilizer stem volume responses, but not enough to be statistically significant (p = 0.11). Clones varied in growth efficiency and partitioning to individual tissues, but clone-by-fertilizer interactions were not observed. Clonal variability was observed in root morphology, and maximum rooting depth showed a significant clone-by-fertilizer interaction. Clones with rapid growth rates can be selected with a range of other desirable traits. Short-term (i.e. weeks) responses to fertilization are often inconsistent with long-term (i.e. years) responses, but are critical to understanding growth responses. We investigated carbon allocation in two full-sibling clones of loblolly pine under two levels of fertilizer application over four months in a greenhouse. Using monthly harvests of some trees and ecophysiological measurements throughout, we determined carbon allocation on a monthly scale. In response to fertilizer application, both clones reduced allocation belowground and increased allocation to foliage to some extent, increasing whole-canopy photosynthetic capacity. However, these changes in allocation were ephemeral. By the end of the experiment, root-shoot ratios were no longer significantly affected by fertilizer application. Clones had allocation patterns distinct from one another, with one allocating more belowground and the other allocating more to stem mass. While their overall growth responses to fertilizer application were similar, the physiological mechanisms that resulted in these responses were different between clones. Results of the two studies indicate that while fertilizer responses may not need to be included when testing clones for deployment, knowledge of the fertilizer responses of widely-deployed clones would offer forest managers opportunities to apply clone-specific precision-silvicultural systems to optimize growth rates and manage for a range of products. / Ph. D.

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