Impacts potentiels d’un changement climatique sur le pergélisol dans le nord canadien

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Impacts de l'écoulement souterrain sur la dégradation du pergélisol

Les changements climatiques mesurés dans le Nord-ouest canadien au cours du XXIe siècle entraînent une dégradation du pergélisol. Certaines des principales conséquences physiques sont la fonte de la glace interstitielle lors du dégel du pergélisol, l’affaissement du sol et la réorganisation des réseaux de drainage. L’effet est particulièrement marqué pour les routes bâties sur le pergélisol, où des dépressions et des fentes se créent de façon récurrente, rendant la conduite dangereuse. Des observations et mesures de terrain effectuées à Beaver Creek (Yukon) entre 2008 et 2011 ont démontré qu’un autre processus très peu étudié et quantifié dégradait le pergélisol de façon rapide, soit la chaleur transmise au pergélisol par l’écoulement souterrain. Suite aux mesures de terrain effectuées (relevé topographique, étude géotechnique du sol, détermination de la hauteur de la nappe phréatique et des chenaux d’écoulement préférentiels, température de l’eau et du sol, profondeur du pergélisol et de la couche active), des modèles de transfert de chaleur par conduction et par advection ont été produits. Les résultats démontrent que l’écoulement souterrain dans la couche active et les zones de talik contribue à la détérioration du pergélisol via différents processus de transfert de chaleur conducto-convectifs. L’écoulement souterrain devrait être pris en considération dans tous les modèles et scénarios de dégradation du pergélisol. Avec une bonne caractérisation de l’environnement, le modèle de transfert de chaleur élaboré au cours de la présente recherche est applicable dans d’autres zones de pergélisol discontinu.

Study of baleen whales’ ecology and interaction with maritime traffic activities to support management of a complex socio-ecological system

Thesis written in co-mentorship with Robert Michaud.

Évaluation de l’effet des vagues de bateau sur les conditions hydrauliques près des berges en milieu fluvial

Les vagues de bateau ajoutent une pression supplémentaire sur les berges de rivières et doivent être considérées dans les modèles de prédiction des taux de recul des berges. L’objectif de cette étude est d’examiner le rôle des vagues de bateau sur l’écoulement et le transport en suspension le long des berges en milieu fluvial. Pour atteindre cet objectif, nous utilisons un transect perpendiculaire à la berge de quatre courantomètres électromagnétiques (ECMs) mesurant deux dimensions de l’écoulement et deux turbidimètres (OBSs) placés dos à dos, orientés vers la berge et le large pour mesurer les conditions moyennes et turbulentes de l’écoulement longitudinal et vertical ainsi que les flux de sédiments en suspension provoqués par les vagues. Une chaloupe à moteur de 16 pieds, équipée d’un moteur 40 hp, a été utilisée afin de générer des vagues. Nous avons mesuré l’effet de trois distances à partir de la berge (5, 10, 15 m) et trois vitesses de bateau (5, 15 et 25 km/h) et cinq répliques de chaque combinaison de distance et de vitesse ont été réalisées, totalisant 45 passages. Nous avons caractérisé la variabilité des conditions d’écoulement, de vagues et de transport de sédiments et nous avons réalisé des analyses spectrales afin de séparer les portions oscillatoire et turbulente de l’écoulement généré par les vagues de bateau. L’effet de la distance et de la vitesse du bateau sur le transport de sédiments est non-linéaire et la réponse sédimentaire induite par les passages de bateau montre une variabilité importante entre les répliques et les deux sondes OBS, ce qui suggère un changement morphologique induit par les vagues de bateau. Les corrélations entre les variables d’écoulement et de transport montrent l’importance des relations entre le cisaillement et la puissance de la portion turbulente de l’écoulement avec le transport de sédiments. Cette étude a permis de quantifier les relations entre la dynamique des vagues et les flux de concentrations de sédiments en suspension, ce qui représente une contribution importante au développement de mesures de mitigation dans les environnements fluviaux où les berges sont fragilisées par le trafic plaisancier.

Studies on the macrobenthos of mudbanks of Southwest cost of India

The present study was undsrtaken.with the objectives to assess the distribution and density of population of benthic animals with special reference to macrofauna from the south west coast of India from ' Malippursa 1 in the north to Alleppey in the south, to evaluate significant difference, if any, in the number and distribution of animals in th md bank regions and other intermittent stations, to examine the influence of bottom stability on the distribution of fauna, to observe the effect of the environmental parameters on the distribution pattern of nacrofauna, and to evaluate the nature and depthpwise distribution of the benthic fishery. The region selected for the investigation is one of the nest important fishing grounds in India for bottom fishing especially for prawns, covering a distance of about 60 kns in length.total number of thirty stations in five transects at right angles to the coast, each consisting of six stations were surveyed. The six stations in a transect were at depths of 5 m, 10m, 20:, 30:, 35m and 45m respectively formation of the Iudbanke, popularly known as 'Ghaknra' in the local language, is a peculiar phenomenon along the ooaet of Kerala and provides a good fishing ground.quantitative distribution of the mecrofauna chewed that the maximum number of organism was near the 35 n contour line in the first three profiles whereas in the fourth and fifth profiles it was at 20 n and 30 m depth respectively. The density of the fauna wee comparatively poor in shallow water etatione at depths 5-‘IO M.was a general decline in the numerical abundance and biomass of the bottom fauna in all the stations during the monsoon period. There has been very little yearly change in the composition of the fauna during the two years‘ study.

“Assessment of Heavy Metals in the Environmental Compartments of the Central and Northern Coast of Kerala, India”

The nearshore marine ecosystem is a dynamic environment impacted by many activities, especially the coastal waters and sediments contiguous to major urban areas. Although heavy metals are natural constituents of the marine environment, inputs are considered to be conservative pollutants and are potentially toxic, accumulate in the sediment, are bioconcentrated by organisms and may cause health problems to humans via the food chain. A variety of metals in trace amounts are essential for biological processes in all organisms, but excessive levels can be detrimental by acting as enzyme inhibitors. Discharge of industrial wastewater, agriculture runoff and untreated sewage pose a particularly serious threat to the coastal environment of Kerala, but there is a dearth of studies in documenting the contaminant metals. This study aimed principally to assess such contamination by examining the results of heavy metal (Cu, Pb, Cr, Ni, Zn, Cd and Hg) analysis in seawater, sediment and benthic biota from a survey of five transects along the central and northern coast of Kerala in 2008 covering a 10.0 km stretch of near shore environment in each transect. Trophic transfer of metal contaminants from aquatic invertebrates to its predators was also assessed, by employing a suitable benthic food chain model in order to understand which all metals are undergoing biotransference (transfer of metals from a food source to consumer).The study of present contamination levels will be useful for potential environmental remediation and ecosystem restoration at contaminated sites and provides a scientific basis for standards and protective measures for the coastal waters and sediments. The usefulness of biomonitor proposed in this study would allow identification of different bioavailable metals as well as provide an assessment of the magnitude of metal contamination in the coastal marine milieu. The increments in concentration of certain metals between the predator and prey discerned through benthic food chain can be interpreted as evidence of biotransference.

Spatio-temporal variation of microphytoplankton in the upwelling system of the south-eastern Arabian Sea during the summer monsoon of 2009

The phytoplankton standing crop was assessed in detail along the South Eastern Arabian Sea (SEAS) during the different phases of coastal upwelling in 2009.During phase 1 intense upwelling was observed along the southern transects (8◦N and 8.5◦N). The maximum chlorophyll a concentration (22.7 mg m −3) was observed in the coastal waters off Thiruvananthapuram (8.5◦N). Further north there was no signature of upwelling, with extensive Trichodesmium erythraeum blooms. Diatoms dominated in these upwelling regions with the centric diatom Chaetoceros curvisetus being the dominant species along the 8◦N transect. Along the 8.5◦N transect pennate diatoms like Nitzschia seriata and Pseudo-nitzschia sp. dominated. During phase 2, upwelling of varying intensity was observed throughout the study area with maximum chlorophyll a concentrations along the 9◦N transect (25 mg m−3) with Chaetoceros curvisetus as the dominant phytoplankton. Along the 8.5◦N transect pennate diatoms during phase 1 were replaced by centric diatoms like Chaetoceros sp. The presence of solitary pennate diatoms Amphora sp. and Navicula sp. were significant in the waters off Kochi. Upwelling was waning during phase 3 and was confined to the coastal waters of the southern transects with the highest chlorophyll a concentration of 11.2 mg m−3. Along with diatoms, dinoflagellate cell densities increased in phases 2 and 3. In the northern transects (9◦N and 10◦N) the proportion of dinoflagellates was comparatively higher and was represented mainly by Protoperidinium spp., Ceratium spp. and Dinophysis spp.

Spechte als ökologische Indikatoren in Natur- und Wirtschaftswäldern im Bialowiera-Wald (Ostpolen)

Die vorliegende Untersuchung analysiert die Eignung der "Spechtgemeinschaft" als ökologische Indikatorengruppe und formuliert vor dem Hintergrund der Ergebnisse Forderungen und Empfehlungen für einen "spechtgerechten" Umgang mit Wäldern. Die Habitatnutzung von sieben Spechtarten beim Nahrungserwerb wurde über einen Zeitraum von zwei Jahren in urwaldartigen und forstlich genutzten Beständen verschiedener Waldgesellschaften systematisch beobachtet. Das Untersuchungsgebiet ist der Bialowieza-Wald im äußersten Osten Polens, wo in enger räumlicher Nachbarschaft Natur- und Wirtschaftswaldflächen bearbeitet werden konnten. Die Beobachtungen erfolgten zwischen Anfang März 1999 und Ende Februar 2001 und wurden zu allen Jahreszeiten durchgeführt. Vier der insgesamt sechs Probeflächen repräsentieren die wichtigste Laubwaldgesellschaft des Gebietes, das Tilio-Carpinetum, die übrigen zwei die wichtigste Nadelwaldgesellschaft, das Peucedano-Pinetum. Die Hälfte der zwischen 42 und 54 ha großen Probeflächen lag im streng geschützten Urwaldreservat des Bialowieza-Nationalparkes, die übrigen in forstlich genutzten Waldbeständen. Zusätzlich wurde ein 2,5 km langes Transekt durch bewirtschafteten Erlen-Eschen-Auenwald und sehr naturnahen Erlenbruch bearbeitet. Die Probeflächen wurden in ein Raster aus 50x50m großen Quadranten unterteilt. Zur Beobachtung der Spechte beim Nahrungserwerb erfolgten 21 Begehungen je Probefläche bzw. Transekt. Die Probeflächen wurden dazu auf parallelen Linien mit Abständen von je 100m begangen, Startpunkt und Startrichtung wurden variiert. Zur Charakterisierung der Vegetation und Bestandesstruktur erfolgten Erhebungen zur Baumartenzusammensetzung, Größenklassenverteilung der Bäume, Totholzanteil und Krautvegetation. 1332 Beobachtungen von Spechten beim Nahrungserwerb konnten ausgewertet werden. Der Buntspecht wurde in allen Flächen am häufigsten gesehen. Mittel-, Weißrücken- und Kleinspecht wurden überwiegend in den Tilio-Carpineten beobachtet, in den Naturwäldern häufiger als in den bewirtschafteten Beständen. Der Dreizehenspecht wurde im Nadelwald und stärker mit Fichten durchmischtem Laubwald angetroffen. Bei Schwarz- und Grauspecht konnte keine klare Vorliebe für bestimmte Waldgesellschaften ermittelt werden. Der Buntspecht ernährte sich vor allem im Herbst und Winter überwiegend von fetthaltigen Samen und wurde dann meist beim Bearbeiten von Fichten- oder Kiefernzapfen in Schmieden beobachtet. Der Mittelspecht suchte als "Sammelspecht" seine Nahrung vor allem an den Oberflächen der Stämme und Äste. Klein-, Weißrücken-, Dreizehen- und Schwarzspecht traten als Hackspechte in Erscheinung. Die wenigen Daten zum Grauspecht reichen nicht zur Ermittlung der bevorzugten Nahrungserwerbstechnik aus. Bei Bunt-, Mittel- und Weißrückenspecht konnte eine deutliche Vorliebe für die Stieleiche als Nahrungsbaum nachgewiesen werden. Der Dreizehenspecht ist jedoch die einzige der beobachteten Arten mit einer weitgehenden Spezialisierung auf eine bestimmte Baumart, er nutzte in allen Waldgesellschaften meist die Fichte. Insgesamt bevorzugten die Spechte Bäume mit großen Stammdurchmessern, beim Kleinspecht ist diese Vorliebe allerdings nur schwach ausgeprägt. Totholz wurde von Weißrücken-, Dreizehen- und Kleinspecht bei der Nahrungssuche bevorzugt, vom Mittelspecht jedoch nur gelegentlich genutzt. Beim Buntspecht zeigte der Totholz-Nutzungsanteil erhebliche Unterschiede zwischen verschiedenen Baumarten. Liegendes Totholz spielte in den Tilio-Carpineten im Vergleich zu stehendem Totholz und toten Teilen lebender Bäume nur eine geringe Rolle für Nahrung suchende Spechte.

Resource use pattern and agroecosystem functioning in Rawanganga micro-watershed in Garhwal Himalaya, India

Agro-ecological resource use pattern in a traditional hill agricultural watershed in Garhwal Himalaya was analysed along an altitudinal transect. Thirty one food crops were found, although only 0.5% agriculture land is under irrigation in the area. Fifteen different tree species within agroforestry systems were located and their density varied from 30-90 trees/ha. Grain yield, fodder from agroforest trees and crop residue were observed to be highest between 1200 and 1600 m a.s.l. Also the annual energy input- output ratio per hectare was highest between 1200 and 1600 m a.s.l. (1.46). This higher input- output ratio between 1200-1600 m a.s.l. was attributed to the fact that green fodder, obtained from agroforestry trees, was considered as farm produce. The energy budget across altitudinal zones revealed 95% contribution of the farmyard manure and the maximum output was in terms of either crop residue (35%) or fodder (55%) from the agroforestry component. Presently on average 23%, 29% and 41% cattle were dependent on stall feeding in villages located at higher, lower and middle altitudes respectively. Similarly, fuel wood consumption was greatly influenced by altitude and family size. The efficiency and sustainability of the hill agroecosystem can be restored by strengthening of the agroforestry component. The approach will be appreciated by the local communities and will readily find their acceptance and can ensure their effective participation in the programme.

Incidencia de la explotación minera en la disputa territorial en el municipio de Segovia. 2002-2010

El interés de la presente investigación está sostenido en analizar la estructuración de la política pública minero-energética, los instrumentos utilizados para su posterior implementación en el municipio de Segovia, Antioquia, y la incidencia que tiene en las tensiones de los actores que tienen presencia en este lugar. Se utiliza la Acumulación por Desposesión para la interpretación de los hechos ocurridos en Segovia, donde se procede a evidenciar que la imposición o inclusión de nuevos modos de producción, genera resistencias que entran en disputa entre sí y que producen la reconfiguración espacial del municipio.

Dynamics and mixing in the Upper Ocean Layer

S'estudia la resposta de la capa de barreja oceànica al forçament atmosfèric considerant dades obtingudes durant 12 dies d'abril del 2001 a 42 estacions a través de l'Atlàntic nord seguint aproximadament la latitud de 53ºN. Aquestes dades inclouen, a més de variables atmosfèriques, mesures de CTD, velocitats amb ADCP i dades de microestructura obtingudes amb un perfilador de caiguda lliure. En aquest últim cas, s'han desenvolupat tècniques de processament de les dades que també es presenten aquí. El transsecte estudiat segueix la posició climatològica del rotacional mitjà anual del vent igual a zero i travessa el corrent del Labrador i algunes branques i meandres del Corrent Atlàntic Nord. El forçament atmosfèric es va caracteritzar per vents intensos i fluxos superficials de calor negatius, tot i que, tal com es dedueix de la comparació del gruix de la capa de barreja amb la longitud de Monin-Obukov, la barreja induïda pel vent va dominar sobre la convectiva durant tot el transsecte.

Development of practical methodology and indicators for on-farm animal welfare assessment

163 p.

Models to predict the distribution and abundance of breeding ducks in Canada

Detailed knowledge of waterfowl abundance and distribution across Canada is lacking, which limits our ability to effectively conserve and manage their populations. We used 15 years of data from an aerial transect survey to model the abundance of 17 species or species groups of ducks within southern and boreal Canada. We included 78 climatic, hydrological, and landscape variables in Boosted Regression Tree models, allowing flexible response curves and multiway interactions among variables. We assessed predictive performance of the models using four metrics and calculated uncertainty as the coefficient of variation of predictions across 20 replicate models. Maps of predicted relative abundance were generated from resulting models, and they largely match spatial patterns evident in the transect data. We observed two main distribution patterns: a concentrated prairie-parkland distribution and a more dispersed pan-Canadian distribution. These patterns were congruent with the relative importance of predictor variables and model evaluation statistics among the two groups of distributions. Most species had a hydrological variable as the most important predictor, although the specific hydrological variable differed somewhat among species. In some cases, important variables had clear ecological interpretations, but in some instances, e.g., topographic roughness, they may simply reflect chance correlations between species distributions and environmental variables identified by the model-building process. Given the performance of our models, we suggest that the resulting prediction maps can be used in future research and to guide conservation activities, particularly within the bounds of the survey area.

Short-eared Owl (Asio flammeus) surveys in the North American Intermountain West: utilizing citizen scientists to conduct monitoring across a broad geographic scale

The Short-eared Owl (Asio flammeus) is an open-country species breeding in the northern United States and Canada, and has likely experienced a long-term, range-wide, and substantial decline. However, the cause and magnitude of the decline is not well understood. We set forth to address the first two of six previously proposed conservation priorities to be addressed for this species: (1) better define habitat use and (2) improve population monitoring. We recruited 131 volunteers to survey over 6.2 million ha within the state of Idaho for Short-eared Owls during the 2015 breeding season. We surveyed 75 transects, 71 of which were surveyed twice, and detected Short-eared Owls on 27 transects. We performed multiscale occupancy modeling to identify habitat associations, and performed multiscale abundance modeling to generate a state-wide population estimate. Our results suggest that within the state of Idaho, Short-eared Owls are more often found in areas with marshland or riparian habitat or areas with greater amounts of sagebrush habitat at the 1750 ha transect scale. At the 50 ha point scale, Short-eared Owls tend to associate positively with fallow and bare dirt agricultural land and negatively with grassland. Cropland was not chosen at the broader transect scale suggesting that Short-eared Owls may prefer more heterogeneous landscapes. On the surface our results may seem contradictory to the presumed land use by a “grassland” species; however, the grasslands of the Intermountain West, consisting largely of invasive cheatgrass (Bromus tectorum), lack the complex structure shown to be preferred by these owls. We suggest the local adaptation to agriculture represents the next best habitat to their historical native habitat preferences. Regardless, we have confirmed regional differences that should be considered in conservation planning for this species. Last, our results demonstrate the feasibility, efficiency, and effectiveness of utilizing public participation in scientific research to achieve a robust sampling methodology across the broad geography of the Intermountain West.