Living on the edge: utilising lidar data to assess the importance of vegetation structure for avian diversity in fragmented woodlands and their edges

Context

In agricultural landscapes, small woodland patches can be important wildlife refuges. Their value in maintaining biodiversity may, however, be compromised by isolation, and so knowledge about the role of habitat structure is vital to understand the drivers of diversity. This study examined how avian diversity and abundance were related to habitat structure in four small woods in an agricultural landscape in eastern England.

Objectives

The aims were to examine the edge effect on bird diversity and abundance, and the contributory role of vegetation structure. Specifically: what is the role of vegetation structure on edge effects, and which edge structures support the greatest bird diversity?

Methods

Annual breeding bird census data for 28 species were combined with airborne lidar data in linear mixed models fitted separately at (i) the whole wood level, and (ii) for the woodland edges only.

Results

Despite relatively small woodland areas (4.9–9.4 ha), bird diversity increased significantly towards the edges, being driven in part by vegetation structure. At the whole woods level, diversity was positively associated with increased vegetation above 0.5 m and especially with increasing vegetation density in the understorey layer, which was more abundant at the woodland edges. Diversity along the edges was largely driven by the density of vegetation below 4 m.

Conclusions

The results demonstrate that bird diversity was maximised by a diverse vegetation structure across the wood and especially a dense understorey along the edge. These findings can assist bird conservation by guiding habitat management of remaining woodland patches.

     

Oxytocin modulates the pulsatile secretion of prostaglandin F2alpha in initiated luteolysis in cattle

Subluteolytic doses of prostaglandin F2alpha analogue (oestrophan) given i.m. and oxytocin (OT) antagonist (CAP) and noradrenaline (NA) infused into the abdominal aorta were used to test the importance of luteal OT in pulsatile secretion of prostaglandin F2alpha (PGF) during luteolysis in heifers (n = 17). In experiment 1, heifers were pre-infused for 30 minutes with saline on either day 17 of the oestrous cycle (group 1; n = 4) or on day 18 of the oestrous cycle (group 2; n = 3), and with CAP (8 mg per animal) on day 17 of the oestrous cycle (group 3; n = 4). Next, heifers were injected with oestrophan (30 microg per animal). Injection of oestrophan in Group 3 increased OT concentrations (P < 0.001) to values similar to those observed during spontaneous luteolysis (50 to 70 pg ml(-1)). PGFM concentrations in this group also increased (P < 0.001), but were lower (P < 0.05) than the values in groups 1 and 2, CAP given prior to oestrophan decreased both PGFM elevation (P < 0.06) and its area under the curve (P < 0.01), compared to the saline pretreated heifers. In experiment 2 NA (4 mg) was infused twice for 30 minutes at five hour intervals to release OT on day 17 of the oestrous cycle (n = 6). However, during hormone analysis it appeared that three of six heifers had elevated PGFM concentrations (group 1) and three others did not (group 2). NA caused the correlated increase of progesterone and OT secretion (r = 0.68; P < 0.05) in both groups but it only influenced PGF secretion in group 1 only (P < 0.05). We postulate that OT can amplify and modulate the course of induced luteolysis as a regulator of the amplitude of pulsatile PGF secretion. PGF analogue stimulates secretion of endogenous PGF from the uterus in cattle and this may be an important component of the luteolytic response to exogenous PGF.     

Effects of tree mixture on forest productivity: tree species addition versus substitution

European Journal of Forest Research - The effects of tree mixture on stand productivity are usually examined using a substitutive approach whereby productivity in mixed stands is compared to...     

Estimating the biomass and carbon pool of stump systems at a national scale

Countries that are signatories to the UNFCCC and its supplementary Kyoto Protocol are obliged to report changes in carbon pools. These should include the pool of carbon held in tree stumps and roots but, to date, few countries have been able to report this or separate it from the dead-wood pool. The aim of this study was to develop a general system for estimating and monitoring changes in stump system carbon using data from a traditional National Forest Inventory. The system was derived using data based on measurements of carbon (biomass) in inventoried permanent sample plots representing all relevant classes of land-use. With this design it was possible to trace matched carbon at the level of individual trees or stumps back to land-use prior to the 1990 baseline year. Between 1990 and 2003 in Sweden, the average annual net sink of stump systems was estimated to amount to 6.7 Mt CO₂ equiv. year⁻¹ – comparable to the reported net sink in 2008 of about 15 Mt CO₂ equiv. year⁻¹ from the whole Land Use, Land-Use Change and Forestry sector, which excluded any carbon in stump systems. In 2003 the carbon stock of stumps and roots was estimated at 495 Mt CO₂ equiv.; approximately five times that of the dead-wood pool as defined in Sweden, i.e. dead wood that mainly consists of boles. The Intergovernmental Panel on Climate Change requests that reported carbon should be matched to land-use and traced back to the 1990 base year; however, the present study confirms expectations that most carbon in stumps and roots is found on Forest land. The minimum requirements for estimating the carbon pool in stump systems at a national scale using the proposed methodology are that there should be: (i) a consistent time-series of harvest data, usually estimated as merchantable volume; (ii) conversion factors from merchantable volume to stump system biomass at death; and (iii) a representative decomposition model.     

Influence of ingredients on the self-diffusion of aroma compounds in a model fruit preparation: an nuclear magnetic resonance-diffusion-ordered spectroscopy investigation

Diffusion-ordered spectroscopy (DOSY)-pulsed field gradient (PGF) nuclear magnetic resonance (NMR) spectroscopy was used to measure self-diffusion coefficients of aroma molecules in model fruit preparations. The impact of the sucrose content on aroma diffusion was specifically investigated, and the relationship with viscosity, water activity, and dry matter parameters was evidenced. DOSY-PGF NMR spectroscopy was found to be a relevant and accurate technique to follow self-diffusion of aroma compounds at low concentrations in a complex food matrix and to obtain information on diffusion of the sucrose and of the water molecules. We showed that aroma self-diffusion was strongly decreased in fruit preparation because of the high sucrose content, which induces the formation of a network through hydrogen bonds with water. Self-diffusion coefficients were determined for aroma molecules of different natures, and values are related to the physicochemical properties of the molecule.     

Photo-Assisted Degradation,Toxicological Assessment,and Modeling Using Artificial Neural Networks of Reactive Gray BF-2R Dye

This work investigates the degradation of Reactive Gray BF-2R dye (a blend of reactive yellow 145, reactive orange 122 and reactive black 5 dyes) using UV/H₂O₂, Fenton, and photo-Fenton-advanced oxidative processes, with artificial sunlight and UV-C radiations. The photo-Fenton process employing UV-C radiation was the most efficient under the conditions studied. The ideal conditions for the degradation of the dye, determined using a factorial design 2³ and a study of the concentration of hydrogen peroxide ([H₂O₂]), were [H₂O₂] equal to 40 mg L^?1, iron concentration [Fe] of 1 mg L^?1, and pH between 3 and 4. The Chan and Chu non-linear kinetic model predicted the kinetic data with a degradation of over 98% for color and 68% for aromatics after 60 min. The behavior of the chemical oxygen demand fitted the first-order kinetic model well, with a degradation of 64% after 60 min. The Multilayer Perceptron 7-11-2 artificial neural network model enabled to model the degradation process of the aromatics and accurately predict the experimental data. Toxicity tests indicated that the post-treatment samples were non-toxic for Escherichia coli bacteria, and Portulaca grandiflora and Basil sabory seeds. However, they inhibited the growth of Lactuca sativa seeds and Salmonella enteritidis bacteria. The photo-Fenton process with UV-C radiation degraded the dye studied efficiently and the degradation percentages were, on average, 7% and 5% higher for color than those observed when employing the Fenton and UV/H₂O₂ processes, respectively. With the aromatic, however, they were 84% and 62% higher, thus justifying the use of this process.     

A generic framework to assess the representation and protection of benthic ecosystems in European marine protected areas

1. There is concern across the International Council for the Exploration of the Sea (ICES) region that a consideration of vulnerable components and the wider support mechanisms underpinning benthic marine ecosystems may be lacking from the process of marine protected area (MPA) designation, management and monitoring.
2. In this study, MPAs across six European ecoregions were assessed from a benthic ecology perspective. The study included 102 MPAs, designated by 10 countries, and focused on three aspects regarding the role of the benthos in: (i) the designation of MPAs; (ii) the management measures used in MPAs; and (iii) the monitoring and assessment of MPAs.
3. Qualitative entries to a questionnaire based on an existing framework (EU project ‘Monitoring Evaluation of Spatially Managed Areas’, (MESMA) were collected by 19 benthic experts of the ICES Benthic Ecology Working Group. A pedigree matrix was used to apply a numerical scale (score) to these entries.
4. The results showed clear differences in scores between ecoregions and between criteria. The designation‐phase criteria generally achieved higher scores than the implementation‐phase criteria. Poor designation‐phase scores were generally reiterated in the implementation‐phase scores, such as scores for assessment and monitoring.
5. Over 70% of the MPA case studies were found to consider the benthos to some extent during selection and designation; however, this was not followed up with appropriate management measures and good practice during the implementation phase.
6. Poor spatial and temporal coverage of monitoring and ineffective indicators is unlikely to pick up changes caused by management measures in the MPA. There is concern that without adequate monitoring and adaptive management frameworks, the MPAs will be compromised. Also, there could be an increased likelihood that, with regard to the benthos, they will fail to meet their conservation objectives.
7. This assessment was successful in highlighting issues related to the representation and protection of the benthos in MPAs and where changes need to be made, such as expanding the characterization and monitoring of benthic species or habitats of interest. These issues could be attributable to an ongoing process and/or an indication that some MPAs only have ‘paper protection’.