Diss. (sammanfattning) Umeå : Sveriges lantbruksuniversitet, 2005. / Härtill 5 uppsatser.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniversitet, 2005. / Härtill 5 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2009. / Härtill 5 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2009. / Härtill 5 uppsatser.

Thesis (Ph.D.)--Aberdeen University, 2009. / Title from web page (viewed on Mar. 30, 2010). Includes bibliographical references.

Research on the chronic effects of toxic chemicals on individuals, populations, communities, and ecosystems is imperative to regulate pollutants and preserve threatened species and habitats. I designed a two-pronged study to investigate the effects of heavy metal contaminants on small mammal populations, communities and body condition. To compare population and community metrics, I conducted a year-long mark-and-release study from over 5,400 trap nights on a contaminated and reference site within Crab Orchard National Wildlife Refuge, a Superfund site. During the second phase, I compared contaminant residues to body condition in 29 white-footed mice (Peromyscus leucopus) and 21 southern short-tailed shrews (Blarina carolinensis) from the Refuge and from three reference sites. Body weight, age structure, trapping success or species diversity did not differ between sites. Mice from the contaminated site were more abundant with lower reproduction (as number of juveniles per adult female). Cadmium in both livers and kidneys of mice and shrews was significantly greater on the contaminated site. Elevated renal cadmium in mice (96 ± 79 mg/kg dry weight) and shrews (242 ± 166 mg/kg dry weight) from the contaminated site could likely impair physiologic functions with long-term effects. For white-footed mice, increasing renal copper, lead, and nickel were good predictors of low ash, water, and protein but did not correlate significantly with crude lipid content. In shrews, however, metals either showed no relationship or, in the case of renal cadmium and copper were positively related to body condition as increased protein content. Simply comparing animals from reference versus contaminated sites provided few insights into overall community structure or population dynamics of white-footed mice. While metals explained as much as 40% of body condition (ash) in mice, findings in both species are counter-intuitive or refute predictions. Future studies should include manipulative field experiments that pair higher-resolution, biologic responses such as histologic and biomarker assays with population and community dynamics.

Endocrine disrupting chemicals in wild animals, including fish, can disrupt reproduction by causing intersexuality. Organic pollutants, specifically polychlorinated biphenyls (PCBs), have been shown to be estrogenic or anti-androgenic likely contributing to intersexuality in males. Organic pollutants persist in the environment despite being restricted for use in the United States. Bluegills, Lepomis macrochirus, play a crucial role in lake food webs as forage and sport fish and may be affected by PCBs. In the current study, male bluegills collected in 2010 from selected Illinois lakes were analyzed to quantify PCB body residues and the incidence of intersexuality (n=200). Experiments were then conducted in 2011 and 2012 to assess the reproductive output of mature males with varying PCB body residues paired with mature females containing no detectable PCB body residues held in uncontaminated 0.05-hectare research ponds (Southern Illinois University Touch of Nature Pond Facility). Lake-specific male bluegill whole-body tissue PCB body residues ranged from below reporting limit to 2 mg/kg dry weight (non-lipid normalized basis) and varied significantly among lakes (F7,32= 9.59, p<0.0001). No male intersex bluegills were found. In both reproductive experiments, abundance of young declined as male PCB body residues increased (F 4,18 = 13.28; P=0.002). Adult survival was unrelated to reproductive output. Taken together, these results suggest PCBs, which are ubiquitous in aquatic and terrestrial habitats, have the ability to alter male reproductive performance, and possibly population dynamics and community structure through reduced recruitment, in the absence of overt intersexuality.

The Olympia oyster, Ostrea lurida. was overharvested in the early 20th century and is now the focus of restoration efforts in estuaries along the west coast of North America. These efforts would be aided by a better understanding of larval abundance patterns, settlement behavior, and post-settlement performance of oysters in estuaries throughout its range. In Coos Bay, Oregon, all three of these components of the oyster life cycle were investigated at multiple sites. Like adult oysters, larvae were restricted to the upper portion of the bay, although larvae were supplied to sites in the upper bay where settlement was low. Settlement and post-settlement growth was highest at sites of high adult density. These results indicate that in O. lurida, as in many other marine invertebrates, the adult population is subject to bottlenecks at the larval and juvenile stage that can vary spatially. This thesis contains previously unpublished co-authored material. / 2014-12-16

Changes in climate shape biological populations. They can alter spatial distributions, the timing of life history events, and even the species themselves. We are now experiencing a period of rapid directional climate change, alongside seasonal fluctuations. This thesis investigates temporal changes in life history events, phenology, as a climate response. I explore the causes and population level consequences of change in breeding phenology of two wild bird populations from Wytham Woods, UK. I test how great tits (Parus major) and blue tits (Cyanistes caeruleus) achieve temporal synchrony between the peak demands of their breeding and the peak abundance of their prey species (winter moth caterpillars - Operophtera brumata) in an inter-annually variable environment. I demonstrate great tit (Parus major) incubation behaviour fine-tunes the timing of hatching in response to ambient temperatures right up until hatching (Chapter two). Temperatures within the nest box, however, appear to play little role in the breeding phenology of blue tits (Cyanistes caeruleus) (Chapter two). I discuss the merits and limitations of statistical approaches for cue identification (Chapter six), finding the method and time period of data used both affect the cue identified and predictive accuracy. The second part of this thesis explores the influence of a directionally changing environment on great tit phenology. I use an integral projection model (IPM) to predict population dynamics over the 21^st century, showing that if the cues used by both interacting species change sufficiently closely, temporal synchrony can be maintained through both phenotypic plasticity and micro-evolution (Chapter 5). However, if the cues diverge mismatch will arise (Chapter 5) causing population declines when certain thresholds are passed (Chapter 4). This work contributes to understanding how phenological synchrony is achieved, how it might change in the future, and its population impacts. In Wytham Woods it appears that great tits have a great deal of flexibility in multiple components of their breeding cycle, allowing them to retain synchrony with their caterpillar prey in a fluctuating environment. These birds are relatively resilient to negative phenological impacts from climate change. Only if the cues used by the predator and prey completely diverge do we predict consistent declines in population size during this century.

Rising carbon dioxide (CO2) concentrations in the atmosphere will increase the average pCO2 level in the world oceans, which will have a knock-on effect on the marine ecosystem. Coastal seagrass communities one of the most productive marine ecosystems are predicted to benefit from the increase in CO2 levels, but long-term effects of elevated CO2 on seagrass communities are less understood. Population reconstruction techniques was used to investigate the population dynamics of Cymodocea nodosa meadows, exposed to long term elevated CO2 at volcanic seeps off Greece and Italy. Effect of elevated CO2 was noticed on the growth, morphometry, density, biomass and age structure at CO2 seeps. Above to below ground biomass ratio of C. nodosa were higher at CO2 seeps than at reference sites. The plastochrome interval were similar at all CO2 seeps. The shoot age and shoot longevity of plants were lower at seeps than reference sites. The present recruitment (sampled year) of the seagrass were higher than long-term average recruitment of the communities near the seeps. Carbon to nitrogen ratios (%DW) of C. nodosa were higher in leaves at seeps. Annual leaf production was higher near the seeps. This study suggests increased production of C. nodosa under elevated CO2 levels, but other co-factors such as nutrients, trace metal toxicity must also be taken into consideration while predicting effects of future CO2 concentrations. Volcanic CO2 seeps are now being used as natural analogues for ocean acidification studies although these areas can be affected by trace element input and may alter ecosystem responses to gradient in carbonate chemistry. Here Fe and a range of trace elements (Cd, Co, Cu, Hg, Mn, Pb, Ni and Zn) were analysed from sediments and from the roots, rhizomes and leaves of seagrass at six CO2 seeps and reference sites off Greece and Italy. There were higher metal levels in sediment and seagrasses at all CO2 seeps than reference sites. Sediment Quality Guideline Quotient, a commonly used pollution index, indicated that some of the metals (Cd, Cu, Hg, Ni) were in high enough concentrations to have adverse biological effects, such as Cu at Ischia site and Hg at Vulcano. Higher accumulation of elements from sediments in roots and leaves at CO2 seeps were found from Bio Sediment Accumulation Factor index. There were higher levels of Cu, Fe, Mn and Zn in leaves and rhizomes for P. oceanica and higher levels of Cd, Co, Cu, Fe and Zn in C. nodosa compartments at CO2 seeps. Fe and Mn were found with positive correlation within sediment-roots and sediment-rhizomes, whereas Cd, Co and Pb were found with positive correlation in compartments of C. nodosa. In P. oceanica positive correlation were only observed for Cd within sediment-roots and plant compartments. Low pH and ocean acidification increased the concentration of elements at CO2 seeps than reference sites. Thus, caution is needed, when using volcanic seep systems as analogue for the effects of rising CO2, as metals can reach levels that are toxic to seagrass, masking any potential benefits of increased levels of carbon dioxide for seagrass productivity. Net community production (NCP) and community respiration (CR) were measured under air exposed and CO2 enriched conditions for intertidal Z. noltei meadows and unvegetated sediment communities during emersion in summer and winter seasons. Community production and respiration were measured in-situ using benthic chambers. CO2 flux under air and CO2 enriched conditions were measured over a series of short term incubations (30min) using an infra-red gas analyser. Incident photosynthetic active radiation (PAR) was recorded during the incubations covering the daily and seasonal variation. Linear regression model was used to test the effects of irradiance on net community production. NCP of Z. noltei community were higher under CO2 enriched conditions than air exposed conditions in both summer and winter seasons. There was no effect of CO2 on the CR rate of Z. noltei community in summer season. NCP of sediment community were higher in summer season and winter season under CO2 enriched conditions. Sediment CR rates were higher in winter than summer season. The light compensation point of Z. noltei and sediment community were lower in both seasons under CO2 enriched conditions. Seasonal budget of community production was higher in Z. noltei than sediment communities. A clear effect of PAR was noticed on the net community production of both communities. Higher PAR intensities resulted in higher NCP under CO2 enriched conditions for both communities. CO2 enrichment will have a positive effect on the intertidal communities during emersion.