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Life histories predict genetic diversity and population structure within three species of octopus targeted by small-scale fisheries in Northwest MexicoDomínguez-Contreras, José F., Munguia-Vega, Adrian, Ceballos-Vázquez, Bertha P., Arellano-Martínez, Marcial, García-Rodríguez, Francisco J., Culver, Melanie, Reyes-Bonilla, Hector 15 February 2018 (has links)
The fishery for octopus in Northwest Mexico has increased to over 2,000 tons annually, but to date the specific composition of the catch has been ignored. With at least three main species targeted by artisanal fisheries in the region with distinct life histories, the lack of basic biological information about the distribution, metapopulation size and structure of each species could impede effective fisheries management to avoid overexploitation. We tested if different life histories of three species of octopus could help predict observed patterns of genetic diversity, population dynamics, structure and connectivity and how this information could be relevant to the sustainable management of the fishery. We sequenced two mitochondrial genes and genotyped seven nuclear microsatellite loci to identify the distribution of each species in 20 locations from the Gulf of California and the west coast of the Baja California peninsula. We tested five hypotheses derived from population genetic theory based on differences in the fecundity and dispersal potential for each species. We discovered that Octopus bimaculoides with low fecundity and direct development (without a planktonic phase) had lower average effective population size and genetic diversity, but higher levels of kinship, population structure, and richness of private alleles, than the other two species. These features indicated limited dispersal and high local recruitment. In contrast, O. bimaculatus and O. hubbsorum with higher fecundity and planktonic phase as paralarvae had higher effective population size and genetic diversity, and overall lower kinship and population structure than O. bimaculoides. These observations supported higher levels of gene flow over a larger geographical scale. O. bimaculatus with the longest planktonic paralarval duration and therefore larger dispersal potential had differences in the calculated parameters possibly associated with increased connectivity. We propose O. bimaculoides is more susceptible to over exploitation of small, isolated populations and could have longer recovery times than the other two species. This species may benefit from distinct fishery management within each local population. O. bimaculatus and O. hubbsorum may benefit from fishery management that takes into account metapopulation structure over larger geographic scales and the directionality and magnitude of larval dispersal driven by ocean currents and population connectivity among individuals of each locality. The distribution of each species and variations in their reproductive phenology is also important to consider when establishing marine reserves or seasonal fishing closures.
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Gametogenesis and spawning of the elliptical star coral, Dichocoenia stokesi (Cnidaria: Scleractinia) in Southeast FloridaHoke, S. Michael 01 April 2007 (has links)
Reproductive characters of the elliptical star coral Dichocoenia stokesi (Cnidaria: Scleractinia) were investigated based in histological examination of tissues collected in southeastern Florida between September 1999 and September 2000. The study population was predominantly gonochoric with a small incidence of hermaphroditism. Dichocoenia stokesi exhibits intermediate egg size (312.2 ± 40.4μm; mean ± SD) compared with other scleractinian species, suggesting a moderately lecithotrophic larval stage. Although spawning was not directly observed in this study, two separate spawning events per year are inferred from histological slide analyses; the first in late August or early September, and the second in early October. Sea water temperature was significantly positively correlated with female gonadal development in D. stokesi, whereas insolation was significantly inversely correlated with gonadal development. A recent epizootic of White Plague Type II in south Florida appears to be skewing local D. stokesi populations toward smaller - and potentially less fecund - colony sizes, although colony size and fecundity were not correlated in this study. The mean fecundity of the study population is estimated as 1138.1 eggs cm-2 yr-1.
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Florida Fishery-Wide Reproductive Indices of Stone Crab, Menippe mercenaria, and Their Application to Stock Assessment and ManagementCrowley, Claire Elizabeth 28 March 2012 (has links)
The stone crab, Menippe mercenaria, supported the third most valuable fishery in Florida in 2016. Declining catch per unit effort (CPUE) and overall negative trend in landings since 2000 have raised concerns among fisherman, researchers, and fishery managers about the resiliency of the fishery. The Florida Fish and Wildlife Research Institute estimated that the Florida stone crab fishery has been overexploited since 1997. Overexploited fisheries, such as the commercial stone crab fishery, risk induced changes in life history parameters, such as age at maturation and reproductive output. In turn, these population-level changes have the potential to reduce the spawning stock biomass and future recruitment to the fishery. The research presented in this dissertation was intended to assess the Florida stone crab fishery stock for: 1) size at sexual maturation in females, 2) size at maturation in males, 3) potential fecundity, modeled as a function of spatial and temporal variables, 4) spawning potential ratios, an index that reveals potential recruitment overfishing, by formulating a per recruit model using the reproductive indices developed in this research, and 5) evaluating the impact of management changes on the spawning stock biomass.
The physiological, behavioral, morphological, and functional maturity of female stone crabs were assessed in individuals collected throughout the fished range of the population on the west Florida shelf (Cedar Key – Sawyer Key). Histology was used to determine oocyte maturity, presence of spermatophores, and presence of postovulatory follicles. Decision-tree analysis suggested that 50% of female stone crabs were mature at 43 mm carapace width, when using a combined variable of physiological and behavioral maturity. The decision tree accurately classified 98% of mature females and 85% of immature females. Morphological maturity was assessed using piecewise regression to determine where allometric changes in growth occurred between carapace width and crusher claw length. The transition point between mature and immature females occurred at a carapace width of 66.3 mm. Differences in estimates of size at sexual maturity between morphological and physiological, behavioral, and functional maturity indicate that relative growth of body parts is not a reliable estimate of sexual maturity in stone crabs. Histological analysis revealed that smaller females are contributing to the spawning population more than previously estimated. The corresponding carapace width at which female stone crab claws are vulnerable to harvest, occurs at 78 mm. The new estimates indicated that females contribute to the spawning population 1-2 times prior to vulnerability to the fishery. Continued monitoring of sexual maturity using these methods is recommended to strengthen understanding of the fishery and of interactions between stone crab populations.
Two methods were used to assess sexual maturity physiologically and morphologically in male stone crabs collected throughout the range of the fishable population. Histology was used to identify the production of spermatophores in the anterior vas deferens, indicating physiological maturity, and each crab was assigned a maturity stage. Decision-tree analysis suggested that physiological maturity occurred at a carapace width of 34.8 mm, accurately classifying 98.9% of mature males accurately and 72.5% of immature males. Piecewise regression estimated that the allometric relationship between carapace width and crusher claw length changed at a carapace width of 63.1 mm. The difference between physiological and morphological estimates of size at sexual maturity indicates that, like females, changes in male allometric relationships between body parts may not be a reliable indicator of sexual maturity. Large morphometrically mature males may be more successful in mating encounters, but in times of flux in population size structure, morphologically immature, but physiologically mature, males may have more opportunities for successful mating encounters. Carapace width at which male stone crab claws are vulnerable to the fishery occurs at 88 mm, indicating that they are capable of contributing to the reproductive population multiple times prior to vulnerability to the fishery.
Multiple factors influencing variability in stone crab batch fecundity were quantified across Florida fishery sites, by implementing a negative binomial model. Fecundity was strongly and positively related to carapace width, and parameter estimates indicated that batch fecundity was on average higher at Pavilion Key (southwest Florida) and Tampa Bay (central Florida), relative to Sawyer Key (south Florida) and Cedar Key (northwest Florida) sites at the northern and southern ends of the study area. Fecundity varied among 2013-2016 and was highly variable among months. In general, the lowest batch fecundity occurred in winter and spring months, while peak batch fecundity occurred in July and August, highlighting the common seasonal trend in crustacean reproductive cycles. Comparison to a 1993-1995 study of fecundity estimates in Tampa Bay, Florida indicated that there was little change in stone crab fecundity between individuals collected in 1993 and 2013. However, this temporal relationship accounts for a small portion of the fished population and may not be reflective of the changes over time across the entire fishery. Although sea surface temperature and ocean color data do not explain the variability in fecundity between sites, I hypothesize that food quality and quantity and fishing effort may play critical role in regionally variable individual reproductive output. I suggest that given the variability in reproductive output and regional fishing practices, that further work be dedicated to identifying critical spawning and recruitment areas to ensure resiliency of the stone crab population.
Spawning potential ratios were used to evaluate the impact of alternative biological and management scenarios to the reproductive output in a theoretical stone crab population. The model incorporated the findings of size at maturation and fecundity established in previous chapters, as well as contemporary temperature-dependent declaw mortalities. Spawning potential ratios increased with decreasing size at sexual maturity and were sensitive to past and present estimates of size at sexual maturity, and increasing natural mortality. However, the largest contributor to changes in the fished stock appears to be mortality associated with declawing and releasing stone crabs. We assessed various management scenarios including declaw lengths, vulnerability to capture, and variable season timing and length. Increases in declaw length and size at vulnerability to capture provided moderate protection to the spawning stock. The model estimated that adaptive management regulations which considered the timing and duration of seasonal fishing, based on mean monthly temperatures below 24°C (temperature at which declaw mortality increases), had the potential to greatly reduce mortality, and provided protection to the spawning population. The model was able to examine a wide range of biological and management scenarios; however, more research should be conducted to determine the socioeconomic impact of regulation changes. The Florida stone crab fishery is an amalgamation of unique fishing practices, rich culture, and both regional and economic influence. Evolving fishing practices, conservation initiatives, and environmental conditions have the potential to transform the fishery. Therefore, fisheries managers, scientists, and stakeholders must work cooperatively to ensure the resiliency of the stone crab fishery.
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Polyandry, multiple mating and sexual conflict in a water strider, Aquarius paludumRonkainen, K. (Katri) 17 May 2016 (has links)
Abstract
Sexual selection results from competition between individuals over access to gametes of the opposite sex. Starting with anisogamy, with females producing larger and fewer gametes than males, females usually invest more in reproduction and thus have lower potential reproductive rates than males. Therefore males are traditionally suggested to compete over females whereas females are choosy. The different evolutionary interests between the sexes result in different selection regimes considering e.g. mating rates. In some species, this conflict is even seen as apparent struggles between males and females over mating decision and/or duration, resulting in antagonistic coevolution with both sexes evolving adaptations to gain more control over the other sex. In this thesis, I studied the role of A. paludum female abdominal spines as an adaptation to reject male mating attempts. I studied both the effect of polyandry and multiple matings on female fecundity to distinguish between the potential material and genetic benefits from mating to females. I also explored the role of various male and female morphological traits on precopulatory sexual selection and the consequent female reproductive output. My results show that female abdominal spines are likely evolved through arms races between the sexes to increase female control over mating decision but according to my studies, female spines are not under active selection. Instead, certain male morphological types were more successful in achieving matings, and mating with these males also increased female fecundity. I found that multiple matings increase female fecundity up to a point, supporting a theory of optimal female mating rate. According to my results, the benefits from multiple mating to A. paludum females result from material origin whereas polyandry per se is even detrimental to female fecundity. / Tiivistelmä
Seksuaalivalinta on pohjimmiltaan seurausta yksilöiden välisestä, lisääntymiseen liittyvästä kilpailusta toisen sukupuolen sukusoluista. Seksuaalivalinta on evoluutiomekanismi, joka osaltaan on johtanut sukupuolten välisiin eroihin monissa morfologisissa ja käyttäytymiseen liittyvissä ominaisuuksissa. Sukupuolet eroavat jo siinä, että naaraat tuottavat vähemmän mutta suurempia sukusoluja kuin koiraat. Koska sukupuolet siis investoivat lisääntymiseen jo alkuvaiheessa eri tavalla, niiden välillä on aina jonkin asteinen seksuaalikonflikti. Konfliktin taustalla on sukupuoliin kohdistuva erilainen valintapaine; koiraat saavuttavat usein optimaalisen hedelmällisyytensä suuremmilla parittelujen määrällä kuin naaraat. Joillakin eläinlajeilla seksuaalikonflikti on niin ilmeinen, että se ilmenee koiraan ja naaraan välisinä kamppailutilanteina parittelupäätöksen ja/tai parittelun keston suhteen. Seksuaalikonflikti voi johtaa molemmilla sukupuolilla erilaisiin sopeumiin, jotka lisäävät yksilön kontrollia parittelujen suhteen. Tässä väitöskirjatyössä tutkin naaraan takapäässä sijaitsevien abdominaalisten piikkien merkitystä järvivesimittari A. paludum-naaraiden kyvyssä torjua parittelemaan pyrkiviä koiraita. Tutkin myös polyandrian ja toistuvien parittelujen vaikutusta naaraan hedelmällisyyteen saadakseni selville, lisäävätkö koiraasta johtuvat mahdolliset materiaaliset tai geneettiset tekijät naaraan hedelmällisyyttä. Lisäksi selvitin useiden koiraan ja naaraan morfologisten ominaisuuksien yhteyttä parittelua edeltävään seksuaalivalintaan sekä naaraan hedelmällisyyteen. Tulokseni osoittavat, että naaraan abdominaaliset piikit ovat todennäköisesti kehittyneet seksuaalikonfliktin seurauksena lisäämään naaraan kontrollia parittelupäätöksen suhteen. Niihin ei kuitenkaan nykyisellään näytä kohdistuvan merkittävää valintapainetta. Sen sijaan morfologialtaan tietynlaiset koirastyypit vaikuttavat olevan aktiivisen valinnan kohteena ja parittelu tällaisten koiraiden kanssa lisää myös naaraan hedelmällisyyttä. Toistuvat parittelut saman koiraan kanssa lisäävät naaraan hedelmällisyyttä tiettyyn optimiin asti, mikä tukee teoriaa optimaalisesta parittelujen määrästä. Sen sijaan polyandria itsessään vaikuttaa naaraan hedelmällisyyteen jopa heikentävästi. Niinpä A. paludum-naaraiden saama hyöty useista paritteluista näyttää olevan materiaalista, kun taas polyandriasta saatavia geneettisiä etuja ei tässä tutkimuksessa tullut ilmi.
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Biologia reprodutiva do camarão Processa hemphilli Manning & Chace, 1971 (Caridea : Processidae) na enseada de Ubatuba, SP, Brasil /Talamonte, Natália Bosco January 2020 (has links)
Orientador: Rogério Caetano da Costa / Resumo: O crescimento relativo, a maturidade sexual morfológica e funcional, a fecundidade, o investimento reprodutivo e a razão sexual de Processa hemphilli foram investigados. Testou-se também, a relação de tais aspectos reprodutivos com fatores abióticos como temperatura e salinidade da água de fundo, teor de matéria orgânica e phi. Os camarões foram coletados sazonalmente, do outono de 2016 até o outono de 2019 na Enseada de Ubatuba, litoral norte paulista, por meio de arrastos com uma rede “mini ottertrawl”. Para analisar os fatores abióticos, a água de fundo foi coletada através de uma garrafa de Van Dorn e o sedimento, com um pegador de Van Veen. Os indivíduos foram identificados quanto ao sexo e para as análises do crescimento relativo as seguintes estruturas foram mensuradas (mm): comprimento da carapaça (CC), comprimento do própodo (Pp), carpo (Cp) e mero (Mp) do primeiro (1) e do segundo (2) par de pereópodos, largura da segunda pleura abdominal (2Pl), comprimento do apêndice interno (AI) nos machos e fêmeas, e quanto ao comprimento do apêndice masculino (AM) nos machos. As relações que melhor evidenciaram mudanças na taxa de crescimento entre jovens e adultos, apontando a maturidade sexual morfológica foram: CC x Cp2 nos machos CC x 2Pl nas fêmeas, com maturidade sexual estimada em 3,2 e 3,6 mm CC para machos e fêmeas respectivamente. A maturidade sexual funcional encontrada foi de 3,3 mm CC. A fecundidade média estimada foi de 256,22 ± 134,62 com correlação positiva entr... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The relative growth, morphological and functional sexual maturity, fertility, reproductive investment and sex ratio of Processa hemphilli were investigated. It was also tested, a relation of reproductive aspects with abiotic factors like temperature and salinity of the bottom water, content of organic matter and phi. Shrimps were collected seasonally, from autumn 2016 to autumn 2019 in the Ubatuba Bay, north of São Paulo, in trawls with a “mini otter-trawl” net. To analyze abiotic factors, the bottom water was collected using a Van-Dorn bottle and sediment, with a Van-Veen tracker. The individuals were identified according to sex and for the analysis of relative growth, the following structures were measured (mm): carapace length (CL), length of the propodus (Pl), carpus (Cl) and mere (Ml) of the first (1 ) and the second (2) pair of pereopods, width of the second abdominal pleura (2Pl), length of the internal appendage (IA) in males and females, and as for the length of the male appendix (MA) in males. The relationships that best evidenced changes in the growth rate between young population and adults, pointing to the morphological sexual maturity were: CC x Cp2 in males CC x 2Pl in females, with sexual maturity estimated at 3.2 and 3.6 mm CC for males and females respectively. The functional sexual maturity found was 3.3 mm CL. The estimated average fertility was 256.22 ± 134.62 with a positive correlation between the number of eggs and the length of the carapace, indicatin... (Complete abstract click electronic access below) / Mestre
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Trichomoniasis of the Utah Agricultural Experiment Station Dairy HerdJensen, Rue 01 May 1939 (has links)
Bovine trichomoniasis is a venereal infection that reduces the fecundity of cattle. It is caused by Trichomonas foetus, a flagellated protozoan which inhabits the genital tract, causing inflammation and partial sterility. Both sexes are susceptible to infection. In females it is usually of short duration and frequently terminates sponaneously following abortion. In males the disease has both acute and chronic stages. During the acute stage the prepucial membranes become inflamed and a muco-purulent discharge develps in which trichomonads are abundant. In the following chronic stage symptoms disappear, but the animal remains a carrier and is a dangerous source of infection to healthy cows. Diagnosis is made by examining the material from infect organs for the specific parasite. The cell body of Trichomonas foetus is fusiform or napiform. It varies from 9 to 20 microns in length, and from 3 to 7 microns in width. Its salient features are an undulating membrane and 4 flagella arising from the blepharoplast, 3 of which are anterior and free, the fourth proceeds caudad bordering the undulating membrane for its entire length and projecting unattached behind. By means of the flagella and undulating membrane the organism move jerkily through an irregular course, as is characteristic of the genus Trichomonas. Dovine trichomoniasis has a wide geographic distribution. In Europe it has been reported from Italy, France, Germany, Holland, and England. Futamura has reported it from Japan. In the United States the infection is known to be present in the states of New York, Pennsylvania, Iowa, Illinois, Maryland, Texas, Michigan, California, and Utah. Survey work done in Utah under the direction of the Utah Agricultural Experiment Station includes examination of herds in Cache, Utah, Davis, Sanpete, and Sevier Counties. Infections were found present in all counties where examinations were made except Sevier. Because of unrestricted commerce of cattle among the important live-stock centers, it is supposed that trichomoniasis is widely spread and probably exists in some cattle in the majority of the counties of the state.
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Spatiotemporal variation in the relative fitness of a northern and a southern ecotype of Arabidopsis thalianaGyllingberg, Jonathan January 2021 (has links)
Terrestrial plants exist in almost every habitat on the earth, ranging from warm and moist tropical rainforests, hot and dry deserts, and to cold and barren tundras. Furthermore, a single species may encounter different climatic conditionshabitats within its range distribution which climatic conditions differs from one to another. In this study, I examine the flowering phenology and fitness of two locally adapted genotypes of Arabidopsis thaliana, one from the southern range limit (Italy) and one from the northern range limit (Sweden) in Europe, in an outdoor common-garden experiment in Uppsala. Flowering start was recorded to characterize flowering phenology, whilst survival and fecundity was recorded to characterize fitness. Flowering start differed significantly between the two genotypes as with the Swedish genotype startinged flowering 24 days later than the Italian genotype. The Italian genotype had higher fitness (number of fruits per seedling planted), which was due to a slightly higher survival and fecundity. The relative fitness of the two genotypes was thus intermediate to that observed in reciprocal transplants between the native sites of origin of the two populations.
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Mountain Big Sagebrush (Artemisia tridentata ssp vaseyana) Seed ProductionLandeen, Melissa L 01 December 2015 (has links) (PDF)
Big sagebrush (Artemisia tridentata Nutt.) is the most widespread and common shrub in the sagebrush biome of western North America. Of the three most common subspecies of big sagebrush (Artemisia tridentata), mountain big sagebrush (ssp. vaseyana; MBS) is the most resilient to disturbance, but still requires favorable climactic conditions and a viable post-fire seedbank for successful unassisted recovery. This study was designed to assess MBS seed production throughout post-fire recovery. We performed 2 pilot studies to develop methods for estimating seed production and plant age. The results of the pilot studies and a space-for-time substitution strategy were used to measure seed production on 13 sites ranging from 10-33 years post-fire. We hypothesized that seed rain (mean seeds produced/ m2) would peak before stand density had maximized due to decreasing individual plant fecundity (mean seeds produced/ plant) in high density stands. We measured population density and individual plant fecundity for three size classes of MBS and used forward stepwise regression analysis to identify environmental factors influencing seed production over time. Density for small (basal stem diameter (BSD) <1 cm) and medium-sized (BSD=1-3 cm) plants was consistently low and was not affected by time since fire (TSF), while large-sized (BSD > 3 cm) plant density increased steadily with TSF (p=0.0002). Plant fecundity decreased with TSF for all three size classes (p range = 0.019 – 0.0506), with large plants dominating reproductive output. Small and medium-sized plant fecundity was negatively correlated with winter precipitation (p range = 0.0106-0.0174), while large plant fecundity was positively correlated with winter precipitation (p<0.0001) and negatively correlated with elevation (p=0.0001). Despite losses in plant fecundity over time for all size classes, steady recruitment in population density resulted in increased seed rain (p=0.0039), suggesting that increases in stand density compensated for losses in individual plant fecundity. Results partially support our hypothesis that the time required for MBS seed rain to be maximized was not tightly bound to indicators of stand maturation. Understanding the factors that influence post-fire seed production can help land managers better manage for successful recovery by providing them with tools for evaluating seed production capabilities of MBS communities.
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Distribution of chemistry and sexual fecundity in the lichenized-fungi, Xanthoparmelia cumberlandia and Xanthoparmelia coloradoensis on Boulder Mountain, Aquarius Plateau, UTJackson, Heather Bird 01 December 2004 (has links) (PDF)
Three aspects of Xanthoparmelia cumberlandia and Xanthoparmelia coloradoënsis populations found at two elevations are explored: clustering of secondary chemicals and the resulting implications for taxonomic distinctions, the usefulness of thallus size as an indirect measure of sexual fecundity, and the frequency of sexual reproduction.
First, we use clustering of 46 chemicals produced by X. cumberlandia and X. coloradoënsis to evaluate the adequacy of the current taxonomic distinction between them. Using principal components analysis and UPGMA, we find that the currently recognized species boundaries indicated by the presence of stictic acid in X. cumberlandia and salazinic acid in X. coloradoënsis are supported by distinct differences in their chemotypes (combinations of secondary chemicals). Norstictic acid, which the literature also associates with X. cumberlandia, is found frequently in both X. cumberlandia and X. coloradoënsis, and is not a good distinguishing characteristic. No chemical difference between sexually fecund and sterile individuals was found.
Second, we test the claim that thallus size can be used as an indirect measure of sexual fecundity. By comparing the number of apothecia, the total area of the apothecia, and the presence or absence of apothecia with thallus area, we found positive correlations between these measures of sexual fecundity and thallus size which are statistically significant. However, the total variation explained by these predictors is limited, and is significantly affected by elevation and micro-environmental features such as proximity to trees. We conclude that size is not a reliable synonym for sexual fecundity in X. cumberlandia and X. coloradoënsis.
Third, we make inferences concerning the frequency of sexual reproduction based on the frequency of sexual structures, rare chemicals, and unique chemotypes. We predicted that sexual reproduction would be more frequent at lower elevations, consistent with a common pattern found in plants and animals. The frequency of sexual structures indicates that sexual reproduction is more common at the lower elevation, while frequency of rare chemicals and chemotypes implies that outcrossing is more common at the upper elevation. Since these indicators lead to opposing conclusions, we encourage the use of molecular markers to estimate the frequency of outcrossing directly.
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The Effects of Soil Phosphorus on <i>Acer rubrum</i> FecundityPeters, Anna L. 11 June 2014 (has links)
No description available.
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