Life Sciences Commons^™

Ecological Costs And Benefits Of Defenses In Nectar, Lynn S. Adler, Rebecca E. Irwin

Dartmouth Scholarship

The nectar of many plant species contains defensive compounds that have been hypothesized to benefit plants through a variety of mechanisms. However, the relationship between nectar defenses and plant fitness has not been established for any species. We experimentally manipulated gelsemine, the principal alkaloid of Carolina jessamine (Gelsemium sempervirens), in nectar to determine its effect on pollinator visitation, nectar robber visitation, and male and female plant reproduction. We found that nectar robbers and most pollinators probed fewer flowers and spent less time per flower on plants with high compared to low nectar alkaloids. High alkaloids decreased the donation of fluorescent …

Interannual Variation Of Stratification In Lower Chesapeake Bay, Christopher S. Katzenmiller

OES Theses and Dissertations

Stratification in the water column can prove to be an important indicator to the state of the water column and ecosystem. The focus of this research is to evaluate trends in stratification in the Lower Chesapeake Bay. Detailed analysis was performed on a 14 year data set to study interannual variation in the region of study. Potential energy anomaly was used to quantify stratification. Potential energy anomaly is the amount of energy required to mix a water column. It is determined from the vertical density structure of density. Potential energy anomaly is the departure of potential energy from climate conditions. …

The Biology Of Canadian Weeds. 131. Polygonum Aviculare L., Mihai Costea, François J. Tardif

Biology Faculty Publications

A review and assessment of biological information as well as personal data are provided for Polygonum aviculare in Canada. The species has been revised taxonomically and the six subspecies that occur in Canada are presented. Three of the subspecies, P. aviculare subsp. aviculare, P. aviculare subsp. neglectum and P. aviculare subsp. depressum are weeds introduced to Canada from Europe. A fourth subspecies, P. aviculare subsp. buxiforme is apparently native to North America. The geographical distribution of the latter four subspecies is very wide. Plants exhibit a high phenotypic plasticity and genetic variability, and they easily adapt to a multitude …

The Large Genome Constraint Hypothesis: Evolution, Ecology And Phenotype, Charles A. Knight, Nicole A. Molinari, Dmitri A. Petrov

Biological Sciences

• Background and Aims If large genomes are truly saturated with unnecessary ‘junk’ DNA, it would seem natural that there would be costs associated with accumulation and replication of this excess DNA. Here we examine the available evidence to support this hypothesis, which we term the ‘large genome constraint’. We examine the large genome constraint at three scales: evolution, ecology, and the plant phenotype.

• Scope In evolution, we tested the hypothesis that plant lineages with large genomes are diversifying more slowly. We found that genera with large genomes are less likely to be highly specious – suggesting a large …

Natural History And Karyology Of The Yucatán Vesper Mouse, Otonyctomys Hatti, Hugh H. Genoways, Robert M. Timm, Mark D. Engstrom

University of Nebraska State Museum: Mammalogy Papers

Seventeen specimens of the rare Yucatán vesper mouse, Otonyctomys hatti, are now known from Belize, Guatemala, and the Mexican states of Campeche, Quintana Roo, and Yucatán. We herein report a second specimen of O. hatti, from Belize, extending the known geographic range of the species 95 km to the southeast in the country. This is the first location at which O. hatti has been taken sympatrically with the Central American vesper mouse, Nyctomys sumichrasti. We also report data on three additional specimens of O. hatti from Campeche. Nyctomys and Otonyctomys share similar habits and habitat requirements, and …

Beiträge Zur Ökologie Und Verbreitung Der Steppenwühlmaus Microtus Brandti Radde, 1861 In Der Mongolei = Ecology And Distribution Of The Steppe Vole Microtus Brandti Radde, 1861 In Mongolia, N. Dawaa, Michael Stubbe, Annegret Stubbe

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

Microtus brandti is one of the most important pest species of Mongolian rodents. Since the publication of Bannikov (1954) the area of expansion is increased, in the Archangaj-Aimag 200 km westward, in the Central Aimag 70 km to the North and in the north-eastern part of Dornogov’- Aimag about 110 km to the South. In years of gradation the plant cover was exterminated up to 100%. We can distinguish a zone of exposed harmfulness with a damage of 70-100%. In this region 16 great centers of infestation were listed. Between 1925 and 1985 six important calamities were noticed, in intervals …

Das Arteninventar Der Avifauna Der Mongolei Während Einer Nord-Süd-Durchquerung 1997, Tobias Stenzel, Michael Stubbe, R. Samjaa, Annegret Stubbe, C. Dulamsuren

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

Here we present a detailed report on bird biodiversity of ecosystems along a North-South transect through Mongolia in 1997whic h serves as a guideline for further research projects and training for students in all Mongolian vegetation zones from northern steppes to southern deserts.

Two hundred fifty-five bird species were observed between 21st of July and 10th of August 1997. The main study sites were located in the North the Selenge-Orchon-basin with meadows and dune woodlands 15 km southern from Suchbaatar, the Middle Gobi-Aimag with desert steppes and sajrs (covered with Ulmus pumila) and in the Bordzongijn-gobi in the South …

First Results Of Wild Ass Research In The South Gobi Aymag/Mongolia In 2003 And 2004, Annegret Stubbe, Michael Stubbe, N. Batsajchan, R. Samjaa, S. Doržderem

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

The population of the Mongolian wild ass belongs to the nominate form Equus hemionus hemionus described by Pallas in 1775. This species is adapted to semidesert habitats in the Gobi region and is listed in the Red Book of Mongolia as well as on appendix I of the Washington Convention (CITES). Mapping of the northern border of the distributional range showed a remarkable decrease in size in comparison to the maps of Murzaev (1954) or Bannikov (1954). The pressure of civilization, settlements, motorization, and increasing numbers of domestic livestock in connection with the occupation of water resources and illegal hunting …

On The Enigmatic Distribution Of The Honduran Endemic Leptodactylus Silvanimbus (Amphibia: Anura: Lep Todactylidae), W. Ronald Heyer, Rafael O. De Sá, Sarah Muller

Biology Faculty Publications

Most species of the frog genus Leptodactylus occur in South America, and all authors who have treated the zoogeography of the genus have concluded that it originated somewhere in South America (e.g., Savage 1982). Savage (1982,518) summarized the historical herpetofaunal units of the Neotropics as follows: "All evidence points to an ancient contiguity and essential similarity of a generalized tropical herpetofauna that ranged over tropical North, Middle, and most of South America in Cretaceous-Paleocene times. Descendents of this fauna are represented today by the South and Middle American tracks (Elements). To the north of this fauna ranged a subtropical-temperate Laurasian …

Spatial Ecology Of Slatey-Grey Snakes (Stegonotus Cucullatus, Colubridae) On A Tropical Australian Floodplain, Gregory P. Brown, Richard Shine, Thomas Madsen

Faculty of Science - Papers (Archive)

The extent, sequence, synchrony and correlates of diel displacements by animals can provide powerful insights into the ecological and social factors that shape an organism's day-to-day activities, but detailed data on spatial ecology are available for very few tropical taxa. Radiotelemetric monitoring of 25 slatey-grey snakes (Stegonotus cucullatus) on a floodplain in the Australian wet-dry tropics for periods of 40 to 355 d (mean=195 d, 136 locations per snake) provided extensive information on habitat use, movement patterns and home range size of these large slender-bodied colubrids. All radio-tracked animals were nocturnal, sheltering by day in soil cracks and …

The Challenge Of Environmental Protection, Jennifer Mattei

Biology Faculty Publications

Connecticut is in the midst of a demographic transition to a period of lower population growth. These demographic changes will help check the pressures exerted on the state's natural resources by population growth. Water, air, soil, energy sources, food, fisheries, forests, and biodiversity are common pool resources upon which we depend in ways that transcend political boundaries. Those governing Connecticut should help turn the state into a model of how to manage natural resources by halting forest fragmentation, reducing pollution, and promoting environmental science education.

The Morphological, Anatomical And Ecological Properties Of Endemic Onosma Bracteosum Hausskn. & Bornm. (Boraginaceae)Species, Öznur Ergen Akçi̇n, Ali̇ Engi̇n

Turkish Journal of Botany

The endemic Onosma bracteosum Hausskn. & Bornm. (Boraginaceae) was investigated morphologically, anatomically and ecologically. It has setae with tuberculate bases. The stem is 15-35 cm tall and erect. The leaves are equifacial and amphistomatous. Stomata cells are anisocytic and anomocytic. The stomata index is 21.25 for the upper epidermis and 25 for the lower epidermis. This plant generally prefers sandy-loamy, sandy-clayey and loamy soils. In the soil samples, the N (23%), P (26%) and K (27%) concentrations were lower in the generative periods than in the vegetative periods. According to the results of plant nutrient analysis, N% (1.140-3.274), P% (0.172-0.403) …

Ecology Of The Rock Shrimp Sicyonia Dorsalis Kingsley, 1878 (Crustacea: Sicyoniidae) In A Subtropical Region Of Brazil, Rogerio Caetano Da Costa, Adilson Fransozo, Maria Lucia Negreiros-Fransozo

Gulf and Caribbean Research

The present study analyzes the abundance and distribution of the rock shrimp Sicyonia dorsalis, in relation to water temperature, salinity, depth, organic matter content, and sediment texture in Mar Virado (MV), Ubatuba (UBA) and Ubatumirim (UBM), 3 distinct bays along the northern coast of São Paulo State (23°S, 45°W), Brazil. Six transects were taken in each bay, 4 being parallel to the coastline and 2 next to the rocky shores. Monthly samples were taken over a 2-year period (1998 and 1999) with a shrimp fishing boat equipped with double-rig nets. A total of 2,498 specimens was obtained with 804 …

Observations On The Ecology, Reproduction And Behavior Of Spermophilus Bennett, 1835 (Mammalia: Rodentia) In Turkey, Şaki̇r Özkurt, Nuri̇ Yi̇ği̇t, Ercüment Çolak, Mustafa Sözen, Muhammed Mouradi Gharakheloo

Turkish Journal of Zoology

Field and laboratory investigations on the ecology, reproduction and behavior of Spermophilus citellus and Spermophilus xantophrymnus were performed over a period of 4 years. Both S. citellus and S. xanthophrymnus are diurnal species and occupy semiarid steppe areas in Turkish Thrace and Anatolia, respectively. Distribution of the former species is confined to restricted steppe areas in Turkish Thrace whilethe, latter lives on the Anatolian steppe, and is sympatric with Meriones tristami, Mesocricetus brandthi, Allactaga williamsi and Microtus spp. The burrows of both species have one entrance, and are built separately in the field. They constitute small social colonies and communicate …

Water Quality Conditions And Restoration Of Submerged Aquatic Vegetation (Sav) In The Tidal Freshwater James River: 2003-2004, Ken Moore, Betty Neikirk, Britt Anderson, Jessie Campbell

Reports

In 2003-2004 wild celery (Vallisneria americana) whole shoots and seeds were transplanted into four sites in the Hopewell region of the tidal James River. The SAV transplants were sampled by the Virginia Institute of Marine Science (VIMS) for survivorship and growth at bi-weekly to monthly intervals throughout the growing season. Concurrently, water quality sampling was conducted at bi-weekly intervals throughout the year for water column nutrients, chlorophyll a, suspended solids, water transparency and other chemical and physical constituents important for SAV growth. Objectives of the study were to: 1) expand the SAV transplanted plots within the study sites previously transplanted; …