University of East Anglia

About: University of East Anglia is a education organization based out in Norwich, Norfolk, United Kingdom. It is known for research contribution in the topics: Population & Climate change. The organization has 13250 authors who have published 37504 publications receiving 1669060 citations. The organization is also known as: UEA.

Life history correlates of responses to fisheries exploitation

Abstract: We use an approach based on phylogenetic comparisons to identify life history correlates of abundance trends in 18 intensively exploited fish stocks from the north–east Atlantic. After accounting for differences in fishing mortality, we show that those fishes that have decreased in abundance compared with their nearest relatives mature later, attain a larger maximum size, and exhibit significantly lower potential rates of population increase. Such trends were not evident in a more traditional cross–species analysis. This is the first phylogenetically independent evidence to link life histories with abundance trends, and provides a quantitative basis for assessing vulnerability of fish populations to exploitation. Our approach can be applied to the conservation and management of other exploited taxa.

COPSE: a new model of biogeochemical cycling over Phanerozoic time

Abstract: We present a new model of biogeochemical cycling over Phanerozoic time. This work couples a feedback-based model of atmospheric O2 and ocean nutrients (Lenton and Watson, 2000a, 2000b) with a geochemical carbon cycle model (Berner, 1991, 1994), a simple sulfur cycle, and additional components. The resulting COPSE model (Carbon-Oxygen-Phosphorus-Sulfur-Evolution) represents the co-evolution of biotic and abiotic components of the Earth system, in that it couples interactive and evolving terrestrial and marine biota to geochemical and tectonic processes. The model is forced with geological and evolutionary forcings and time-dependent solar insolation. The baseline model succeeds in giving simultaneous predictions of atmospheric O2, CO2, global temperature, ocean composition, δ13C and δ34S that are in reasonable agreement with available data and suggested constraints. The behavior of the coupled model is qualitatively different to single cycle models. While atmospheric pCO2 (CO2 partial pressure) predictions are mostly determined by the model forcings and the response of silicate weathering rate to pCO2 and temperature, multiple negative feedback processes and coupling of the C, O, P and S cycles are necessary for regulating pO2 while allowing δ13C changes of sufficient amplitude to match the record. The results support a pO2 dependency of oxidative weathering of reduced carbon and sulfur, which raises early Paleozoic pO2 above the estimated requirement of Cambrian fauna and prevents unrealistically large δ34S variation. They do not support a strong anoxia dependency of the C:P burial ratio of marine organic matter (Van Cappellen and Ingall, 1994, 1996) because this dependency raises early Paleozoic δ13C and organic carbon burial rates too high. The dependency of terrestrial primary productivity on pO2 also contributes to oxygen regulation. An intermediate strength oxygen fire feedback on terrestrial biomass, which gives a pO2 upper limit of ∼1.6PAL (present atmospheric level) or 30 volume percent, provides the best combined pO2 and δ13C predictions. Sulfur cycle coupling contributes critically to lowering the Permo-Carboniferous pCO2 and temperature minimum. The results support an inverse dependency of pyrite sulfur burial on pO2 (for example, Berner and Canfield, 1989), which contributes to the shuttling of oxygen back and forth between carbonate carbon and gypsum sulfur. A pO2 dependency of photosynthetic carbon isotope fractionation (Berner and others, 2000; Beerling and others, 2002) is important for producing sufficient magnitude of δ13C variation. However, our results do not support an oxygen dependency of sulfur isotope fractionation in pyrite formation (Berner and others, 2000) because it generates unrealistically small variations in δ34S. In the Early Paleozoic, COPSE predicts pO2=0.2–0.6PAL and pCO2>10PAL, with high oceanic [PO43-] and low [SO4=]. Land plant evolution caused a ‘phase change’ in the Earth system by increasing weathering rates and shifting some organic burial to land. This change resulted in a major drop in pCO2 to 3 to 4PAL and a rise in pO2 to ∼1.5PAL in the Permo-Carboniferous, with temperatures below present, ocean variables nearer present concentrations, and PO4:NO3 regulated closer to Redfield ratio. A second O2 peak of similar or slightly greater magnitude appears in the mid-Cretaceous, before a descent towards PAL. Mesozoic CO2 is in the range 3 to 7PAL, descending toward PAL in the Cretaceous and Cenozoic.

The costs of reproduction in the collared flycatcher Ficedula albicollis

Abstract: There has been considerable interest in testing Lack's1 hypothesis that the most frequent clutch size should be the one which yields the highest number of viable offspring. Many tests, however, have shown that the clutch size that produces the most fledglings is actually larger than the most frequent size2,3. This discrepancy has been accounted for by suggesting that high fecundity may result in a reduction in fledgling survival1, juvenile survival4, adult survival5,6, subsequent fecundity7 or the fecundity of the offspring8 or, alternatively, that there is a relationship between parent quality or territory quality and brood size9. We evaluate three different methods of determining these costs and conclude that experimental manipulations provide the only reliable means of determining the costs. The collared flycatcher, Ficedula albicollis, on the island of Gotland forms an isolated population with a remarkably high site fidelity of both adults and young such that the lifetime reproductive success can be assessed with an accuracy rarely possible under natural conditions. Experimental modifications of the actual clutch size showed that the main costs of an enlarged clutch were that the juveniles were less likely to survive, that the subsequent fecundity of the parents was reduced and the offspring had a lower fecundity. Adult survival was unaffected by clutch size.

Greenspace and obesity: a systematic review of the evidence.

Abstract: Greenspace is theoretically a valuable resource for physical activity and hence has potential to contribute to reducing obesity and improving health. This paper reports on a systematic review of quantitative research examining the association between objectively measured access to greenspace and (i) Physical activity, (ii) Weight status and (iii) Health conditions related to elevated weight. Literature searches were conducted in SCOPUS, Medline, Embase and PYSCHINFO. Sixty studies met the inclusion criteria and were assessed for methodological quality and strength of the evidence. The majority (68%) of papers found a positive or weak association between greenspace and obesity-related health indicators, but findings were inconsistent and mixed across studies. Several studies found the relationship varied by factors such as age, socioeconomic status and greenspace measure. Developing a theoretical framework which considers the correlates and interactions between different types of greenspace and health would help study design and interpretation of reported findings, as would improvement in quality and consistency of greenspace access measures. Key areas for future research include investigating if and how people actually use greenspace and improving understanding of the mechanisms through which greenspace can improve health and, in particular, if physical activity is one such mechanism.