Habitat use by the South-American rattlesnake (Crotalus durissus) in south-eastern Brazil

Habitat use affects food intake, reproductive fitness and body temperature control in reptiles. Habitat use depends on both the characteristics of the animal and the environmental heterogeneity. In this study we investigated habitat use in a population of the South-American rattlesnake, Crotalus durissus, in a cerrado (the Brazilian savanna) remnant, in south-eastern Brazil. In general, snakes appeared to be thermal generalists. However, they showed substrate temperature preferences in the rainy season, when they selected colder substrates during the day and warmer substrates at night. Individuals were predominantly active on the surface and more frequently found under bushes. Furthermore, in general, the principal component analysis results indicate that rattlesnakes are generalists regarding the microhabitat variables examined in this study. These habitat characteristics, associated with a low thermal selectivity, indicate that rattlesnakes are able to colonize deforested areas where shade occurrence and vegetation cover are similar to those in the cerrado.

Caves as a Winter Refuge by a Neotropical Harvestman (Arachnida, Opiliones)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Patterns of oocyte development in natural habitat and captive Salminus hilarii Valenciennes, 1850 (Teleostei: Characidae)

Fecundity and oocyte development in Salminus hilarii female brood stock were analyzed with the aim of investigating the impact of migration impediment on oogenesis. Histological analyses of the ovaries were performed in adult females caught in two different environments-the TietA(a) River (natural) and captivity-and the gonadossomatic index, oocyte diameter and fecundity determined. Five germ cell development stages (oogonium, perinucleolar, cortical alveoli, vitellogenic, ripe) and two other structures (postovulatory follicles and atretic oocytes) were observed in females caught in the river. Captive animals lacked the ripe oocytes and postovulatory follicles and had a relatively higher number of atretic oocytes. Females in captivity are known to produce larger oocytes, and they release fewer eggs in each spawn (absolute fecundity) when compared with animals that are able to migrate. Our results suggest that the TietA(a) River is undergoing alterations which are being reflected in the reproductive performance of S. hilarii, mainly due to the presence of atretic oocytes in females caught in the river. The lack of postovulatory follicles and ripe oocytes in captive animals reveals that migratory impediment negatively impacts final oocyte maturation. However, the stage of maturation reached is adequate for ovulation induction with hormone manipulation.

Problematiska ljudkvalitetsskillnader vid liveproduktioner i samma lokal : En studie av upplevd ljudkvalitet vid två DJ-akters framträdanden under Dreamhack Winter 2014

Syftet med denna undersökning är bidra med förklaringar till varför upplevda ljudkvalitetsskillnader kan uppstå mellan olika akters framträdanden vid event och festivaler trots att de använder samma utrustning och är i samma lokal och att förklaringarna ska utgöra en kunskapskälla för dem som eftersträvar en god ljudkvalité vid liveframträdanden. De metoder som har används är fallstudie, webbenkät, intervjuer och egen observation. Webbenkäten användes på Dreamhack Winter 2014 där en grupp undersökningsdeltagare svarade på frågor om två olika DJ-akter på scenen i D-hallen, Elmia. Fem personer deltog som intervjupersoner: scenansvarig från Dreamhack, tre ljudtekniker ifrån olika ställen i Sverige och en person som jobbar med ljudteknisk konsultation och ljudmätning. Samtliga intervjuer genomfördes via mail. Intervjuerna eftersträvade att ge kunskap om dessa personers funderingar kring ljudkvalitetsproblemet och scenansvarig svarade på frågor om scenen på Dreamhack. En observation av upplevd ljudkvalitet och ljudteknikernas arbetssätt genomfördes av mig själv på Dreamhack Winter 2014. Resultatet från såväl enkätundersökningen som den egna observationen visar att inga stora upplevda skillnader fanns mellan de två akterna på Dreamhack Winter 2014. De upplevda skillnader som observerades var negativa anmärkningar, så som mängden bas och ljudstyrka. Intervjuerna visade på flera gemensamma åsikter bland ljudteknikerna angående förklaringar till ljudkvalitetsskillnader vid event som Dreamhack Winter 2014 där de ansåg att en kunnig och erfaren ljudtekniker, duktiga musiker, väl genomförd soundcheck och bra och rätt användande av utrustningen på scen krävs för att uppnå en upplevd god ljudkvalitet live. De förklaringar som finns enligt mina analyser och bland ljudteknikerna till negativa ljudkvalitetsskillnader inom liveljud i samma lokal är att ljudteknikern och musikerna är olika duktiga. Utrustning, soundcheck och akustik påverkar också kvalitén. Undersökningens sammantagna resultat tyder på att de upplevda ljudkvalitetetsskillnader som fanns på Dreamhack Winter 2014 berodde på bristande kompetens och engagemang hos tjänstgörande ljudtekniker och upplevda skillnader i bas- ljudnivå i de två DJ-akternas mixar.

Predator Survival Tactics and Use of Habitat Cover in Rana Catesbeiana.

Predator-prey relationships are an important aspect of the natural world, and, because of its relevance to survival and natural selection, is an interesting relationship to study. In amphibian larvae, level of activity and landscape use are often what determines the survival as prey. I studied the anti-predator behavior of the North American bullfrog (Rana catesbeiana) tadpoles when presented with dragonfly (Aeshna) larvae, a known predator of tadpoles. Tadpoles were acclimated to four different habitats with varying degrees of habitat cover, and were transferred to a new habitat with a degree of cover equal to one of the acclimation tanks. A restrained predator, and thus its chemical cue, was introduced, and the behavior, particularly the use of the habitat cover to hide from the perceived risk of predation was observed. A significantly higher frequency of inactivity was found in tank I than in II and III, and inactivity followed a general trend of decreasing with increasing habitat cover. Difference in tank cover was not found to have a significant effect on swimming behavior, but did have a significant effect on hiding behavior, which increased with higher availability. Foraging decreased significantly with the addition of a predator, but did not vary significantly with different levels of cover. Hiding behavior and reducing conspicuous behaviors (like foraging) are probably the behaviors that afford the tadpole the most success at eluding a predator in their natural environment.

The Movement of the Gastrop Littorina Littorea in the Intertidal Zone during the Onset of Winter

The movement of the snail Littorina littoreaon the North Atlantic coast is poorly understood. Most research has concentrated on the vertical distribution of the snail, and suggests that it prefers the low intertidal zone where its food source is most plentiful. In the winter, this distribution is reinforced by a documented seaward migration of snails from the high intertidal zone in response to falling temperatures. From October 14, 2006 to January 22, 2007, I examined the individual movements and recovery of snails in response to the onset of winter. I proposed that falling water and air temperatures drive the majority of snail movement within the intertidal zone, and that water temperature had the greater effect. I also examined the possibility that, in addition to a seaward migration, winter weather patterns in the Gulf of Maine and their effect on the ocean may encourage the wintertime vertical distribution of snails. Finally, I examined the possibility that populations of snails in the comparatively inhospitable high intertidal zone may endure the winter if given access to proper resources.

Atlantic Salmon Habitat and Dams in Maine

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Atlantic Salmon Habitat on Maine's Rivers and Streams

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Wildlife Habitat of Maine

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EVALUATION OF THE CONSERVATION LANDS OF MAINE BASED ON PRESENCE OF HABITAT SUITABLE FOR LISTED SPECIES

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HABITAT SUITABILITY ANALYSIS OF THE CRITICALLY ENDANGERED FLORIDA PANTHER

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A PRELIMINARY HABITAT SUITABILITY ANALYSIS FOR THE RESTORATION OF SOUTH CHINA TIGERS IN THE HUPINGSHAN RESERVE, CHINA

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A GIS SUITABILITY ANALYSIS OF WOLF HABITAT IN MAINE

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MODELING POTENTIAL TIGER HABITAT IN HUPINGSHAN-HOUHE ANDMANGSHAN-NANLING NATIONAL NATURE RESERVES, CHINA

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A GIS Suitability Analysis of Wolf Habitat in Maine

The range of the Gray Wolf (Canis lupus), once covering most of North America, has been drastically reduced by an estimated 95% due to habitat loss and extermination by humans. The wolf was extirpated from Maine in the 1800’s. Wolf reintroductions have been suggested for Maine, but there is some debate about how much land is suitable for wolves. I developed a wolf habitat suitability analysis using ArcGIS and data from the Maine Office of GIS and the United States National Atlas. The model incorporates land cover, presence of major roads and railways, conservation land, industrial, non-industrial, and public woodlot ownership, distance from major points of population, deer population, and slope. The model results show areas of high and low wolf suitability in Maine. The model suggests that the best potential habitat for wolves in Maine is situated in the northwest of the state. Possible future reintroductions or natural colonization from other areas would have the highest likelihood of survival in these areas.