Fingerprints of biocomplexity: Taxon‐specific growth of phytoplankton in relation to environmental factors

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110012/1/lno2004494part21446.pd

Nitrogen Deposition Reduces Plant Diversity and Alters Ecosystem Functioning: Field-Scale Evidence from a Nationwide Survey of UK Heathlands

Findings from nitrogen (N) manipulation studies have provided strong evidence of the detrimental impacts of elevated N deposition on the structure and functioning of heathland ecosystems. Few studies, however, have sought to establish whether experimentally observed responses are also apparent under natural, field conditions. This paper presents the findings of a nationwide field-scale evaluation of British heathlands, across broad geographical, climatic and pollution gradients. Fifty two heathlands were selected across an N deposition gradient of 5.9 to 32.4 kg ha−1 yr−1. The diversity and abundance of higher and lower plants and a suite of biogeochemical measures were evaluated in relation to climate and N deposition indices. Plant species richness declined with increasing temperature and N deposition, and the abundance of nitrophilous species increased with increasing N. Relationships were broadly similar between upland and lowland sites, with the biggest reductions in species number associated with increasing N inputs at the low end of the deposition range. Both oxidised and reduced forms of N were associated with species declines, although reduced N appears to be a stronger driver of species loss at the functional group level. Plant and soil biochemical indices were related to temperature, rainfall and N deposition. Litter C:N ratios and enzyme (phenol-oxidase and phosphomonoesterase) activities had the strongest relationships with site N inputs and appear to represent reliable field indicators of N deposition. This study provides strong, field-scale evidence of links between N deposition - in both oxidised and reduced forms - and widespread changes in the composition, diversity and functioning of British heathlands. The similarity of relationships between upland and lowland environments, across broad spatial and climatic gradients, highlights the ubiquity of relationships with N, and suggests that N deposition is contributing to biodiversity loss and changes in ecosystem functioning across European heathlands

Risk for Incident Hypertension Associated With Posttraumatic Stress Disorder in Military Veterans and the Effect of Posttraumatic Stress Disorder Treatment

OBJECTIVE: Posttraumatic stress disorder (PTSD) increases cardiovascular disease and cardiovascular mortality risk. Neither the prospective relationship of PTSD to incident hypertension risk nor the effect of PTSD treatment on hypertension risk has been established. METHODS: Data from a nationally representative sample of 194,319 veterans were drawn from the Veterans Administration (VA) roster of United States service men and women. This included veterans whose end of last deployment was from September 2001 to July 2010 and whose first VA medical visit was from October 1, 2001 to January 1, 2009. Incident hypertension was modeled as 3 events: (1) a new diagnosis of hypertension and/or (2) a new prescription for antihypertensive medication, and/or (3) a clinic blood pressure reading in the hypertensive range (≥140/90 mm Hg, systolic/diastolic). Posttraumatic stress disorder diagnosis was the main predictor. Posttraumatic stress disorder treatment was defined as (1) at least 8 individual psychotherapy sessions of 50 minutes or longer during any consecutive 6 months and/or (2) a prescription for selective serotonin reuptake inhibitor medication. RESULTS: Over a median 2.4-year follow-up, the incident hypertension risk independently associated with PTSD ranged from hazard ratio (HR), 1.12 (95% confidence interval [CI], 1.08-1.17; p < .0001) to HR, 1.30 (95% CI, 1.26-1.34; p < .0001). The interaction of PTSD and treatment revealed that treatment reduced the PTSD-associated hypertension risk (e.g., from HR, 1.44 [95% CI, 1.38-1.50; p < .0001] for those untreated, to HR, 1.20 [95% CI, 1.15-1.25; p < .0001] for those treated). CONCLUSIONS: These results indicate that reducing the long-term health impact of PTSD and the associated costs may require very early surveillance and treatment

Changes in landscape and vegetation of coastal dunes in northwest Europe: a review

In coastal dunes, landscape changes are a rule, rather than an exception. This paper gives an overview of changes in landscape and vegetation with a focus on the past century. The history of dunes is characterised by phases of sand drift, alternated with geomorphological stability. The historical development of dune woodland during these stable phases has been documented for sites all over Europe. Vegetation reconstructions of historical open dune habitats however is very difficult due to limited preservation of fossil remains. People have drastically altered coastal dune landscapes through centuries of exploitation and more recently development of the coast. Historical land use has generally pushed vegetation back into a semi-natural state. During roughly the past century a tendency of increasing fixation and succession is observed on coastal dunes throughout northwest Europe. Six causes of change are discussed. 1) Changes in land use, mainly abandonment of agricultural practices, have led to the development of late successional stages such as scrub and woodland. 2) Crashing rabbit populations due to myxomatosis in the 1950s caused vigorous grass growth and probably stimulated scrub development. 3) A general tendency of landscape fixation is observed due to both natural and anthropogenic factors. 4) Eutrophication, mainly due to atmospheric nitrogen deposition is clearly linked to grass encroachment on acidic but also on some calcareous dunes. 5) The impact of climate change on vegetation is still unclear but probably lengthening of growing season and maybe enhanced CO2 concentrations have led to an acceleration of succession. 6) A general anthropogenisation of the landscape occurs with rapid spread of non-native species as an important consequence. The reconstruction of a natural reference landscape is considered largely unattainable because of irreversible changes and the long tradition of human impact, in many cases since the development of the dunes. Two contradictory elements need reconciliation. First, the general acceleration of succession and scrub and woodland development in particular is partly caused by a decreased anthropogenic interference in the landscape and deserves more appreciation. Second, most biodiversity values are largely linked to open, early succession dune habitats and are threatened by the same tendency. Apart from internal nature management, in which grazing plays an important part, re-mobilisation of stable, senescent dunes is an important challenge for dune management

Pollinator-flower interactions in gardens during the COVID-19 pandemic lockdown of 2020

During the main COVID-19 global pandemic lockdown period of 2020 an impromptu set of pollination ecologists came together via social media and personal contacts to carry out standardised surveys of the flower visits and plants in gardens. The surveys involved 67 rural, suburban and urban gardens, of various sizes, ranging from 61.18° North in Norway to 37.96° South in Australia, resulting in a data set of 25,174 rows, with each row being a unique interaction record for that date/site/plant species, and comprising almost 47,000 visits to flowers, as well as records of flowers that were not visited by pollinators, for over 1,000 species and varieties belonging to more than 460 genera and 96 plant families. The more than 650 species of flower visitors belong to 12 orders of invertebrates and four of vertebrates. In this first publication from the project, we present a brief description of the data and make it freely available for any researchers to use in the future, the only restriction being that they cite this paper in the first instance. The data generated from these global surveys will provide scientific evidence to help us understand the role that private gardens (in urban, rural and suburban areas) can play in conserving insect pollinators and identify management actions to enhance their potential

Pollinator-flower interactions in gardens during the COVID-19 pandemic lockdown of 2020

During the main COVID-19 pandemic lockdown period of 2020 an impromptu set of pollination ecologists came together via social media and personal contacts to carry out standardised surveys of the flower visits and plants in their gardens. The surveys involved 67 rural, suburban and urban gardens, of various sizes, ranging from 61.18o North in Norway to 37.96o South in Australia and resulted in a data set of 25,174 rows long and comprising almost 47,000 visits to flowers, as well as records of plants that were not visited by pollinators. In this first publication from the project we present a brief description of the data and make it freely available for any researchers to use in the future, the only restriction being that they cite this paper in the first instance. As well as producing a data set that we hope will be widely used in the future, the project helped enormously with the health and mental wellbeing of the participants, a by-product of ecological field work that cannot be over-estimated