bluuebunny/crossref_metadata_2025 huggingface dataset:
miLD and booLD Programs for Calculation and Analysis of Corrected Linkage Disequilibrium
Authors: Aulchenko Y. S. , Axenovich T. I. , Mackay I. , Duijn C. M. van
Published: July 2003

We describe software which calculates a set of linkage disequilibrium statistics, including multiallelic D′ corrected by the bootstrap and permutation. The software also provides a tool for maximum likelihood and least squares estimation and testing of a set of hierarchical hypotheses formulated within the framework of the Malecot model of the decay of linkage disequilibrium with distance. Additionally, the bootstrap approach is used for estimation of the model parameter's confidence intervals and for hypothesis testing. The programs are available from http://www.geneticepi.com/Research/software/software.html
Y Chromosome and Mitochondrial DNA Characterization of Pasiegos, a Human Isolate from Cantabria (Spain)
Authors: Maca‐Meyer N. , Sánchez‐Velasco P. , Flores C. , Larruga J.‐M. , González A.‐M. , Oterino A. , Leyva‐Cobián F.
Published: July 2003

Mitochondrial DNA sequences and Y chromosome haplotypes were characterized in Pasiegos, a human isolate from Cantabria, and compared with those of other Cantabrian and neighbouring Northern Spain populations. Cantabria appears to be a genetically heterogeneous community. Whereas Lebaniegos do not differ from their eastern Basque and western Asturian and Galician neighbours, Pasiegos and other non‐Lebaniego Cantabrians show significant differences with all of them. Pasiegos are peculiar for their high frequencies of Y chromosomal markers (E‐M81) with North African assignation, and Y chromosomal (R‐SRY2627) and mtDNA (V, I, U5) markers related to northern European populations. This dual geographic contribution is more in agreement with the complex demographic history of this isolate, as opposed to recent drift effects. The high incidence in Cantabrians with pre‐V and V mtDNA haplotypes, considered as a signal of Postglacial recolonization in Europe from south‐western refugees, points to such refugees as a better candidate population than Basques for this expansion. However, this does not discount a conjoint recolonization.
A Reassessment of Genetic Diversity in Icelanders: Strong Evidence from Multiple Loci for Relative Homogeneity Caused by Genetic Drift
Authors: Helgason A. , Nicholson G. , Stefánsson K. , Donnelly P.
Published: July 2003

There has been some controversy in the literature concerning whether Icelanders are genetically homogenous or heterogeneous relative to other European populations. We reassess this question in the light of large data sets spanning 83 autosomal SNP loci, 14 serogenetic loci, 6622 Y‐chromosomes and 3214 sequences from mtDNA hypervariable segments 1 and 2 (HVS1 and HVS2). Our results strongly support the hypothesis that genetic drift, with a consequent loss of variation, has had a greater impact on Icelanders than most other Europeans. We also analyse 7245 HVS1 sequences from 25 European populations. In line with other studies, we observe a deficit of rare HVS1 haplotypes and an excess of intermediate frequency haplotypes in Icelanders compared to most European populations, with some measures of genetic diversity indicating relative heterogeneity and others indicating relative homogeneity of Icelanders. Simulations indicate that genetic drift, and not admixture (as proposed by Árnason, 2003) is the most likely cause of the atypical Icelandic HVS1 frequency spectrum. These simulations reveal that gene diversity (heterozygosity) and mean pairwise differences are largely insensitive to events in recent population history, while statistics based on the number of haplotypes or segregating sites are much more sensitive. Overall, our analyses strongly indicate that the Icelandic gene pool is less heterogeneous than those of most other European populations.
The Causal Element for the Lactase Persistence/ non‐persistence Polymorphism is Located in a 1 Mb Region of Linkage Disequilibrium in Europeans
Authors: Poulter M. , Hollox E. , Harvey C. B. , Mulcare C. , Peuhkuri K. , Kajander K. , Sarner M. , Korpela R. , Swallow D. M.
Published: July 2003

Expression of lactase in the intestine persists into adult life in some people and not others, and this is due to a cis‐acting regulatory polymorphism. Previous data indicated that a mutation leading to lactase persistence had occurred on the background of a 60 kb 11‐site LCT haplotype known as A (Hollox et al. 2001). Recent studies reported a 100% correlation of lactase persistence with the presence of the T allele at a CT SNP at −14 kb from LCT, in individuals of Finnish origin, suggesting that this SNP may be causal of the lactase persistence polymorphism, and also reported a very tight association with a second SNP (GA –22 kb) (Enattah et al. 2002). Here we report the existence of a one megabase stretch of linkage disequilibrium in the region of LCT and show that the –14 kb T allele and the –22 kb A allele both occur on the background of a very extended A haplotype. In a series of Finnish individuals we found a strong correlation (40/41 people) with lactose digestion and the presence of the T allele. The T allele was present in all 36 lactase persistent individuals from the UK (phenotyped by enzyme assay) studied, 31/36 of whom were of Northern European ancestry, but not in 11 non‐persistent individuals who were mainly of non‐UK ancestry. However, the CT heterozygotes did not show intermediate lactase enzyme activity, unlike those previously phenotyped by determining allelic transcript expression. Furthermore the one lactase persistent homozygote identified by having equally high expression of A and B haplotype transcripts, was heterozygous for CT at the −14 kb site. SNP analysis across the 1 megabase region in this person showed no evidence of recombination on either chromosome between the –14 kb SNP and LCT. The combined data shows that although the –14 kb CT SNP is an excellent candidate for the cause of the lactase persistence polymorphism, linkage disequilibrium extends far beyond the region searched so far. In addition, the CT SNP does not, on its own, explain all the variation in expression of LCT, suggesting the possibility of genetic heterogeneity.
Microbial flora of technological interest in raw ovine milk during 6°C storage
Authors: Sanjuan Silvia , Rúa Javier , García‐Armesto María R
Published: July 2003

Changes in the microbial flora of ovine milk of medium hygienic quality (initial mean total plate count 3.3 × 105 cfu/mL) were studied throughout refrigerated storage at 6°C. Total plate counts after 48 h of refrigerated storage (mean count 4.6 × 105 cfu/mL) were under the current standards in the European Union (EU) for raw ovine milk to be used for cheesemaking after heat treatment. However, after 96 h, mean total plate counts (1.6 × 107 cfu/mL) were above the standards. Lactococci were found at levels higher than Pseudomonas spp. in milk freshly drawn (54.5% and 3.5% of total plate count, respectively) and after 96 h at 6°C (47.9% and 33.9% of total plate count, respectively). Lactobacilli, enterococci, coliforms and thermodurics were found at values lower than lactococci and Pseudomonas spp., before and after refrigerated storage (≤ 0.08% of the total plate count). A significant growth (P < 0.001) was detected for mesophiles, Pseudomonas spp. and lactococci after 96 h of refrigeration at 6°C; however, thermodurics, coliforms, lactobacilli and enterococci, showed no significant increase (P > 0.05). Presumptive Escherichia coli (β‐glucuronidase‐positive) underwent a decrease throughout storage at 6°C.
Market segmentation of cheese consumers: an approach using consumer's attitudes, purchase behaviour and sociodemographic variables
Authors: Mesías Francisco J , Escribano Miguel , Rodríguez De Ledesma Antonio , Pulido Francisco
Published: July 2003

Market segmentation, as a technique to split a market up into segments in which consumers are as homogeneous as possible, is of great importance for companies, as it allows objective markets to be chosen for the application of differentiated marketing policies. The aim of the present work is the segmentation of the cheese market in Extremadura (SW Spain), using cluster analysis.

The data are taken from a survey of cheese consumers in Extremadura; the items of the survey are related to their cheese consumption habits, and their attitudes and preferences with respect to this product. The analysis distinguished four homogeneous consumer groups with respect to several sociodemographic and consumption behaviour variables that are of great interest for subsequent market interventions.
Recent developments in antibody‐based analytical methods for the differentiation of milk from different species
Authors: Moatsou Golfo , Anifantakis Emmanuel
Published: July 2003

The antibody‐based analytical methods for the detection of milk from different species that have been developed in recent years are, for the most part, various enzyme‐linked immunosorbent assay (ELISA) configurations. Polyclonal and, more recently, monoclonal antibodies against total or individual caseins, whey proteins and synthetic peptides corresponding to milk proteins sequences have been used. The assays have been successfully applied to the detection of substitution of ovine or caprine milk by bovine milk and of ovine milk by caprine milk in raw and heat‐treated milks and cheeses.
Rheological properties of reduced lactose whey dispersions
Authors: Mleko S , Janas P , Wang T , Lucey J A
Published: July 2003

The rheological behaviour of reduced lactose whey (RLW) dispersions of several different types of whey products was investigated with dynamic small amplitude oscillatory (SAOS) rheometry and rotational rheometry. The different aggregation states of the proteins were measured by using size‐exclusion chromatography (SEC) with multiangle laser light scattering (MALLS). Differences in the mineral content (especially calcium and phosphate) of the RLW samples contributed to their different rheological properties. Calcium phosphate/whey protein aggregates were probably formed when the mineral content increased, resulting in an increase in the size of the aggregates and higher viscosity. These complexes were also more sensitive to heating.
Rheology and sensory profiling of set‐type fermented milks made with different commercial probiotic and yoghurt starter cultures
Authors: Torre L La , Tamime A Y , Muir D D
Published: July 2003

Varieties of set‐type probiotic fermented milks and yoghurt were made from recombined skimmed milk powder, anhydrous milk fat and commercial starter cultures (direct‐to‐vat inoculation, DVI). Serum separation of fermented milks and yoghurt with high initial rates of syneresis proceeded more slowly than separation of those with low initial rates of syneresis; the decrease during the storage period was linear and the rate of decrease was dependent on the type of starter culture used. The firmness of these products increased over the time period, and the rate of increase was linear and independent of the starter culture. The production of exopolysaccharide material by the starter microflora also influenced syneresis and firmness of the probiotic fermented milks. The average profiles of organic acids of all the products were similar with the exception of two starter cultures that generated the highest level of acetic acid. After cross‐validation, classification of the starter type using the organic acids values correctly predicted the type of starter culture used for 23 out of 24 samples. All the sensory attributes were influenced by the type of starter culture used and the trial, with the exception of viscosity character; acetic acid production by the microbial species of the starter cultures had the greatest influence on the flavour attribute.
Is the taste of British milk chocolate different?
Authors: Beckett Stephen T
Published: July 2003

The flavour of a piece of chocolate can be affected by the type and amount of ingredients present, as well as by the processing techniques used. This article reviews the factors that alter the taste of milk chocolate and considers whether a unique British flavour exists. Chocolate varieties with a wide range of flavours are currently being sold throughout the world and most are available within the UK. It is concluded that the existence of a unique British milk chocolate flavour may be due to the widespread use of chocolate crumb as an ingredient, which introduces a cooked taste into the final product.
Textural and microstructural properties of urfa cheese (a white‐brined Turkish cheese)
Authors: Özer B H , Robinson R K , Grandison A S
Published: July 2003

The texture and microstructure of white‐brined cheeses similar to urfa (a traditional Turkish cheese) were studied. One batch of cheeses was made in the traditional manner and one batch was made from ultrafiltered (UF) milk. Samples from each batch were either ripened in brine after production or scalded in whey for 3 min at 90°C prior to ripening. The results showed only marginal differences in the ripening profiles of both batches of unscalded cheeses, but scalding slowed down the extent of proteolysis in both batches. The scalded cheeses had a firmer texture than the unscalded ones, and the unscalded UF cheese had a more ‘springy’ body than the unscalded traditional cheese. Overall, scalding resulted in a more homogeneous structure, but the unscalded UF cheese had a close texture that resembled the scalded samples. It was concluded that, with respect to texture and structure, cheeses made with UF milk do not need to be scalded after production.
Some properties of set yoghurt made from caprine milk and bovine–caprine milk mixtures fortified by ultrafiltration or the addition of skim milk powder
Authors: Uysal Harun , Kilic Sevda , Kavas Gokhan , Akbulut Necati , Kesenkas Harun
Published: July 2003

Set yoghurt was produced from caprine milk (A), 70% caprine‐30% bovine (B) and 50% caprine–50% bovine milk (C) mixtures, and stored for 14 days at ±4°C. Two methods of fortification, namely ultrafiltration (UF) and the addition of bovine skim milk powder (SMP), were applied to the milk mixtures. Some chemical, physical, microbiological and sensory properties of the six samples were analysed on the 1st, 7th and 14th days of storage. The effects of milk type, concentration method and storage period on the physicochemical and microbiological properties of the samples were investigated statistically.
Influence of different culturing conditions on kefir grain increase
Authors: Schoevers Anine , Britz Trevor J
Published: July 2003

Kefir grains are the natural starter used during kefir production. Factors influencing grain increase—incubation temperature of 18, 22, 25 or 30°C, enrichment with combinations of tryptose (20 g/L) and yeast extract (20 g/L), and cultivation with and without agitation—were studied to develop a method for mass grain production. The highest grain increase (582%) was found with activated grains cultivated with agitation at 25°C in low‐fat milk containing tryptose and replacing the fermented milk daily. Full‐cream milk under the same conditions gave an increase of 522%. Cultivation without agitation resulted in 175% and 173% increases for low‐fat and full‐cream milk, respectively.
Dexamethasone treatment of a canine, but not human, tumour cell line increases chemoresistance independent of P‐glycoprotein and multidrug resistance‐related protein expression
Authors: Mealey K. L. , Bentjen S. A. , Gay J. M. , Hosick H. L.
Published: July 2003

Glucocorticoids are often used in veterinary cancer patients because of their anti‐inflammatory actions, appetite‐stimulating effects, ability to decrease nausea and vomiting associated with some chemotherapy agents, and, in some instances, for their cytotoxic actions on susceptible tumour cells. Veterinary oncologists may not consider the possibility that the use of glucocorticoids may adversely affect response to chemotherapy. There is evidence that glucocorticoids can up‐regulate the expression of multidrug resistance genes in some tissues. Whether or not glucocorticoid‐induced expression of multidrug resistance proteins occurs in tumour cells is not presently known. The purpose of this study was to determine if dexamethasone induces P‐glycoprotein (P‐gp) or multidrug resistance‐related protein 1 (MRP1) in tumour cell lines. A canine osteosarcoma cell line (OS2.4) and a human myeloid leukaemia cell line 60 (HL60) were treated in culture with dexamethasone. The presence of a glucocorticoid receptor was confirmed in both cell lines by reverse‐transcriptase polymerase chain reaction. Western blots for P‐gp and MRP1 expression were performed on vehicle‐treated and dexamethasone‐treated cells. Sensitivity towards several chemotherapeutic drugs (cisplatin (cis‐diamminedichloroplatinum), doxorubicin, methotrexate and vincristine) was determined by 3‐(4,5‐dimthylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. While dexamethasone treatment of OS2.4 cells increased the resistance to cisplatin and methotrexate, an increase in P‐gp or MRP1 expression was not observed. Dexamethasone‐treated HL60 cells did not develop chemoresistance and did not show increased expression of P‐gp or MRP1.
Preclinical evaluation of 5‐aminolevulinic acid‐based photodynamic therapy for canine transitional cell carcinoma
Authors: Lucroy M. D. , Ridgway T. D. , Peavy G. M. , Krasieva T. B. , Higbee R. G. , Campbell G. A. , Blaik M. A.
Published: July 2003

As a prelude to photodynamic therapy, 5‐aminolevulinic acid (ALA) was given orally to healthy dogs. ALA‐induced protoporphyrin IX (PpIX) fluorescence significantly increased in the mucosa of the urinary bladder in an ALA dose‐dependent fashion. Vomiting occurred after ALA administration in 70% of the dogs but did not affect PpIX fluorescence. ALA‐based photodynamic therapy (PDT) of the urinary bladder in healthy dogs caused only submucosal oedema within the bladder wall. No haematologic or serum biochemistry abnormalities were observed after ALA administration. Microscopic haematuria was observed in all the dogs after PDT but was mild and self limiting. ALA‐based PDT was administered to six dogs with transitional cell carcinoma (TCC) of the lower urinary tract. ALA‐based PDT resulted in tumour progression‐free intervals from 4 to 34 weeks in five dogs; one dog with pre‐existing hydronephrosis died shortly after PDT. Dogs with TCC represent an outbred, spontaneous, tumour model for developing PDT protocols for humans with bladder cancer.
Intravenous administration of 9‐aminocamptothecin to dogs with lymphoma
Authors: Moore A. S. , Imondi A. R. , De Souza P. L. , Wood C. A.
Published: July 2003

A colloidal dispersion formulation of 9‐aminocamptothecin (9‐AC) was administered intravenously to 10 dogs with previously untreated, spontaneously occurring, multicentric lymphoma. The dogs received a 72‐h infusion of 9‐AC at a rate of 46.5–51.25 µg m−2 h−1(total dose range 3.35–3.69 mg m−2). This dose range was associated with myelosuppression, consisting principally of neutropenia with a nadir at 7 days following the start of infusion. Neutropenia and thrombocytopenia were the most common toxicoses and are most likely to be dose‐limiting toxicities; low‐grade gastrointestinal signs were rarely seen. Concentrations of 9‐AC lactone, as well as clinical toxicities, compare favourably with those found in humans. Tumour responses were seen in all treated dogs. Response to other chemotherapy, following cessation of 9‐AC treatment, was not obviously compromised even in dogs clinically resistant to 9‐AC. 9‐AC is a novel treatment drug for canine lymphoma, which appears to show great promise.
Postoperative radiotherapy and mitoxantrone for anal sac adenocarcinoma in the dog: 15 cases (1991–2001)
Authors: Turek M. M. , Forrest L. J. , Adams W. M. , Helfand S. C. , Vail D. M.
Published: July 2003

The medical records of 15 dogs with anal sac adenocarcinoma (ASAC) treated with concurrent curative‐intent radiotherapy and mitoxantrone (MX) after surgical removal of the primary tumour were reviewed retrospectively. Radiation was prescribed at 15 daily fractions of 3.2 Gy for a total dose of 48 Gy. MX was given intravenously at a dosage of 5 mg m−2every 3 weeks for five treatment sessions. Twelve dogs received pelvic irradiation to include the regional lymph nodes (LNs) and three received radiation only to the perineum. At the time of diagnosis, four dogs were hypercalcaemic and seven dogs presented with regional LN metastasis. All the dogs with regional LN metastasis received pelvic irradiation, and in three cases, metastatic LNs were treated in the macroscopic disease setting. The median event‐free survival was 287 days, and the median overall survival was 956 days. Acute and chronic radiation complications were common and non‐life threatening, although chronic complications contributed to the decision to euthanize two dogs. The results observed in this retrospective analysis compare favourably with cases of ASAC in the literature related to treatment with surgery and/or chemotherapy.
Sarcoma development after radiotherapy in two dogs
Authors: Mellanby R. J. , Herrtage M. E. , Chantry J. , Dobson J. M.
Published: July 2003

Two dogs were treated with a hypofractionated course of radiotherapy following surgical excision of an intermediate grade mast cell tumour and a round cell tumour, respectively. Both dogs developed a sarcoma of the bone, within the irradiated site, several years after the initial radiotherapy treatment. Bone tumours arising within a previously irradiated area are well‐recognized late radiotherapy side‐effect in humans but have been reported infrequently in dogs. These are the first case reports to describe bone sarcomas in the appendicular skeleton at a site, which had been previously treated by a hypofractionated course of radiotherapy for an unrelated tumour.
Enhanced bioavailability of oral docetaxel by co‐administration of cyclosporin A in dogs and rats
Authors: McEntee M. , Silverman J. A. , Rassnick K. , Zgola M. , Chan A. O. , Tau P. T. , Page R. L.
Published: July 2003

Pharmacokinetic and pharmacodynamic endpoints of intravenously and orally administered docetaxel (DT) with or without oral cyclosporine were characterized in rats and dogs. Plasma samples were analysed for DT using liquid chromatography–mass spectrometry. DT area‐under‐the‐concentration–time curve, plasma clearance and maximum serum clearance were significantly affected by cyclosporine in rats (P ≤ 0.0005). Bioavailability of DT alone and DT combined with cyclosporine was 1.3 and 82%, respectively, in rats. In dogs, cyclosporine resulted in a 14–17‐fold increase in peak DT concentrations (P < 0.0005) and area‐under‐the‐curve (P < 0.0005), and a 17‐fold reduction in DT clearance (P < 0.005). Bioavailability of DT alone was 18 ± 16% and statistically exceeded 100% (251 ± 104%) when combined with cyclosporine in dogs. Two of the six dogs receiving DT plus cyclosporine developed neutropenia, and one of the six dogs experienced vomiting and diarrhoea. Cyclosporine significantly alters the disposition of oral DT in dogs and rats, such that clinically relevant serum concentrations are achievable.
The Scale of Successional Models and Restoration Objectives
Authors: Parker V. Thomas
Published: July 2003

Successional models are used to predict how restoration projects will achieve their goals. These models have been developed on different spatial and temporal scales and consequently emphasize different types of dynamics. This paper focuses on the restoration goal of self‐sustainability, but only in the context of a long‐term goal. Because of the temporal scale of this goal, we must consider the impact of processes arising outside of the restoration site as of greater importance than restoration itself. Because ecological systems are open, restoration sites will be subjected to many external influential processes. Depending on the landscape context, the impact of these processes may not be noticeable, or, at the other extreme, they may prevent the achievement of restoration objectives. A second issue is to emphasize the nature of processes in the long term, that they are a complex of characteristics such as magnitude, frequency, and extent. Ecological systems are only adapted to a range of values in each of these characteristics. Restoration often combines goals that are of different scales. Models appropriate to these goals need consideration.
Restoration Biology: A Population Biology Perspective
Authors: Montalvo Arlee M. , Williams Susan L. , Rice Kevin J. , Buchmann Stephen L. , Cory Coleen , Handel Steven N. , Nabhan Gary P. , Primack Richard , Robichaux Robert H.
Published: July 2003

A major goal of population biologists involved in restoration work is to restore populations to a level that will allow them to persist over the long term within a dynamic landscape and include the ability to undergo adaptive evolutionary change. We discuss five research areas of particular importance to restoration biology that offer potentially unique opportunities to couple basic research with the practical needs of restorationists. The five research areas are: (1) the influence of numbers of individuals and genetic variation in the initial population on population colonization, establishment, growth, and evolutionary potential; (2) the role of local adaptation and life history traits in the success of restored populations; (3) the influence of the spatial arrangement of landscape elements on metapopulation dynamics and population processes such as migration; (4) the effects of genetic drift, gene flow, and selection on population persistence within an often accelerated, successional time frame; and (5) the influence of interspecific interactions on population dynamics and community development. We also provide a sample of practical problems faced by practitioners, each of which encompasses one or more of the research areas discussed, and that may be solved by addressing fundamental research questions.
Ecological Theory and Community Restoration Ecology
Authors: Palmer Margaret A. , Ambrose Richard F. , Poff N. LeRoy
Published: July 2003

Community ecological theory may play an important role in the development of a science of restoration ecology. Not only will the practice of restoration benefit from an increased focus on theory, but basic research in community ecology will also benefit. We pose several major thematic questions that are relevant to restoration from the perspective of community ecological theory and, for each, identify specific areas that are in critical need of further research to advance the science of restoration ecology. We ask, what are appropriate restoration endpoints from a community ecology perspective? The problem of measuring restoration at the community level, particularly given the high amount of variability inherent in most natural communities, is not easy, and may require a focus on restoration of community function (e.g., trophic structure) rather than a focus on the restoration of particular species. We ask, what are the benefits and limitations of using species composition or biodiversity measures as endpoints in restoration ecology? Since reestablishing all native species may rarely be possible, research is needed on the relationship between species richness and community stability of restored sites and on functional redundancy among species in regional colonist “pools.” Efforts targeted at restoring system function must take into account the role of individual species, particularly if some species play a disproportionate role in processing material or are strong interactors. We ask, is restoration of habitat a sufficient approach to reestablish species and function? Many untested assumptions concerning the relationship between physical habitat structure and restoration ecology are being made in practical restoration efforts. We need rigorous testing of these assumptions, particularly to determine how generally they apply to different taxa and habitats. We ask, to what extent can empirical and theoretical work on community succession and dispersal contribute to restoration ecology? We distinguish systems in which succession theory may be broadly applicable from those in which it is probably not. If community development is highly predictable, it may be feasible to manipulate natural succession processes to accelerate restoration. We close by stressing that the science of restoration ecology is so intertwined with basic ecological theory that practical restoration efforts should rely heavily on what is known from theoretical and empirical research on how communities develop and are structured over time.
Restoration Ecology and the Ecosystem Perspective
Authors: Ehrenfeld Joan G. , Toth Louis A.
Published: July 2003

The ecosystem perspective provides a framework within which most other aspects of the ecology of restoration can be incorporated. By considering the ecosystem functions of a restoration project, the restorationist is forced to consider the placement of the project in the landscape—its boundaries, its connections or lack thereof to adjoining ecosystems, and its receipts and losses of materials and energy from its physical surroundings. These characteristics may set limits on the kind(s) of biotic communities that can be created on the site. The ecosystem perspective also gives restorationists conceptual tools for structuring and evaluating restorations. These include the mass balance approach to nutrient, pollutant, and energy budgets; subsidy/stress effects of inputs; food web architecture; feedback among ecosystem components; efficiency of nutrient transfers, primary productivity and decomposition as system‐determining rates; and disturbance regimes. However, there are many uncertainties concerning these concepts, their relation to each other, and their relationships to population‐ and community‐level phenomena. The nature of restoration projects provides a unique opportunity for research on these problems; the large spatial scale of restorations and the freedom to manipulate species, soil, water, and even the landscape could allow ecosystem‐level experiments to be conducted that could not be performed otherwise.
Linking Restoration and Landscape Ecology
Authors: Bell Susan S. , Fonseca Mark S. , Motten Little B.
Published: July 2003

Landscape ecology focuses on questions typically addressed over broad spatial scales. A landscape approach embraces spatial heterogeneity, consisting of a number of ecosystems and/or landscape structures of different types, as a central theme. Such studies may aid restoration efforts in a variety of ways, including (1) provision of better guidance for selecting reference sites and establishing project goals and (2) suggestions for appropriate spatial configurations of restored elements to facilitate recruitment of flora/fauna. Likewise, restoration efforts may assist landscape–level studies, given that restored habitats, possessing various patch arrangements or being established among landscapes of varying diversity and conditions of human alteration, can provide extraordinary opportunities for experimentation over a large spatial scale. Restoration studies can facilitate the rate of information gathering for expected changes in natural landscapes for which introduction of landscape elements may be relatively slow. Moreover, data collected from restoration studies can assist in validation of dynamic models of current interest in landscape ecology. We suggest that restoration and landscape ecology have an unexplored mutualistic relationship that could enhance research and application of both disciplines.
Quantitatively Evaluating Restoration Experiments: Research Design, Statistical Analysis, and Data Management Considerations
Authors: Michener William K.
Published: July 2003

Conceptual and logistical challenges associated with the design and analysis of ecological restoration experiments are often viewed as being insurmountable, thereby limiting the potential value of restoration experiments as tests of ecological theory. Such research constraints are, however, not unique within the environmental sciences. Numerous natural and anthropogenic disturbances represent unplanned, uncontrollable events that cannot be replicated or studied using traditional experimental approaches and statistical analyses. A broad mix of appropriate research approaches (e.g., long‐term studies, large‐scale comparative studies, space‐for‐time substitution, modeling, and focused experimentation) and analytical tools (e.g., observational, spatial, and temporal statistics) are available and required to advance restoration ecology as a scientific discipline. In this article, research design and analytical options are described and assessed in relation to their applicability to restoration ecology. Significant research benefits may be derived from explicitly defining conceptual models and presuppositions, developing multiple working hypotheses, and developing and archiving high‐quality data and metadata. Flexibility in research approaches and statistical analyses, high‐quality databases, and new sampling approaches that support research at broader spatial and temporal scales are critical for enhancing ecological understanding and supporting further development of restoration ecology as a scientific discipline.
Approximating Nature's Variation: Selecting and Using Reference Information in Restoration Ecology
Authors: White Peter S. , Walker Joan L.
Published: July 2003

Restoration ecologists use reference information to define restoration goals, determine the restoration potential of sites, and evaluate the success of restoration efforts. Basic to the selection and use of reference information is the need to understand temporal and spatial variation in nature. This is a challenging task: variation is likely to be scale dependent; ecosystems vary in complex ways at several spatial and temporal scales; and there is an important interaction between spatial and temporal variation. The two most common forms of reference information are historical data from the site to be restored and contemporary data from reference sites (sites chosen as good analogs of the site to be restored). Among the problems of historical data are unmeasured factors that confound the interpretation of historical changes observed. Among the problems of individual reference sites is the difficulty of finding or proving a close match in all relevant ecological dimensions. Approximating and understanding ecological variation will require multiple sources of information. Restoration, by its inherently experimental nature, can further the understanding of the distribution, causes, and functions of nature's variation.
Restoration of Catchment Water Balance: Responses of Clonal River Red Gum (Eucalyptus camaldulensis) to Waterlogging
Authors: Akilan Kandia , Marshall John K. , Morgan Anne L. , Farrell Richard C. C. , Bell David T.
Published: July 2003

Effects of waterlogging were studied in the field and under glasshouse conditions on two clonal lines of Eucalyptus camaldulensis Dehnh (river red gum), which are used in the rehabilitation of damaged agricultural catchments in Western Australia. The plantation of 9‐year‐old trees was in a position that covered a range of waterlogging and salinity conditions. Up‐slope the water table was deeper (0.65–1.5 m), whereas the water table was closer to the ground surface down‐slope (0.45 m in winter; 1.25 m in summer). Salinity was greater downslope and increased at the end of the dry summer, remaining high until diluted by the winter rains. Trees of both clonal lines were smaller downslope and used less water over the year. Clone M80 used more water in winter; clone M66 more in summer. In the field, the roots of clone M80 were evenly distributed through the soil profile, while roots of clone M66 decreased with increasing depth. Production of new root terminals varied with season. Greatest production was in spring and early summer, with much lower production over late autumn and winter. Only clone M66 produced new root terminals at depth (60–75 cm) during the drier months of late summer and early autumn. At this time, saline ground‐water was the main source for water uptake. To explore clonal differences more closely, the effects of prolonged waterlogging were studied under glasshouse conditions. Clone M80 grew similarly under freely drained and continuously waterlogged conditions for the experimental period (21 weeks). The response under continuously waterlogged conditions was achieved through adventitious root production. By contrast, growth of clone M66 was suppressed under continuous waterlogging, a response associated with the lack of adventitious root production. The results from field and glasshouse studies suggest that clone M80 is more adapted to waterlogging by relatively fresh water than clone M66, but that clone M66 may use water of higher salinity than clone M80. Clone M80 would be better suited to higher positions in partially cleared catchments, where rainfall provides relatively fresh soil water. Clone M66 is better suited to lower catchment positions due to its ability to utilize more saline groundwater. Restoration of the water balance of damaged agricultural catchments can be best managed by matching specialized genotypes with particular catchment positions.
Ants as Indicators of Restoration Success: Relationship with Soil Microbial Biomass in the Australian Seasonal Tropics
Authors: Andersen Alan N. , Sparling Graham P.
Published: July 2003

Ants are widely used as bioindicators in Australian land assessment and monitoring programs, particularly in relation to ecosystem restoration following mining. Little is known, however, about the relationship between ant community development and key ecological processes such as nutrient cycling. We have examined the relationship between ant species richness and soil microbial biomass at 17 sites subject to disturbance by mining in the Kakadu region of Australia's Northern Territory. The number of ant species recorded ranged from 7 at an unvegetated site undergoing restoration to 43 at a site that was undisturbed except for edge effects. Soil microbial biomass ranged from 19.3 to 134.3 μgC/g. Ant species richness was positively correlated with soil microbial biomass (r= 0.638), more so than was plant species richness (r= 0.342 for total plant species,r= 0.499 for woody species only). Our findings demonstrate a correlation between aboveground ant activity and belowground decomposition processes at disturbed sites, thereby providing support for the use of ants as indicators of restoration success following disturbance. Interestingly, when a range of undisturbed sites in the region was considered, a negative rather than positive relationship between ant richness and soil microbial biomass was found. This illustrates the importance of distinguishing between variation within a habitat due to disturbance and variation across different habitats when searching for indicators of ecological change.
Terrestrial Invertebrate Community Structure as an Indicator of the Success of a Tropical Rainforest Restoration Project
Authors: Jansen Amy
Published: July 2003

Rainforest restoration is a relatively new endeavor, and few attempts have been made to assess the success of such restoration efforts in terms of the reestablishment of an ecosystem. Small plantings of rainforest tree species have been carried out adjacent to mature rainforest at Lake Barrine National Park in North Queensland, Australia, since 1988. The aim of this project was to assess the leaf litter invertebrate fauna of these plantings as indicators of the success of the restoration process. Plots planted in 1988, 1989, and 1990, as well as adjacent mature rainforest, were sampled in the wet and dry seasons of 1994. Invertebrates were extracted from leaf litter samples with Berlese Funnels and sorted to order. Diversity, the abundance of different size classes and orders of invertebrates, and the abundance of different functional groups were examined. In most respects the 1988 plot was found to differ little from the mature rainforest plots, whereas the 1990 plot lacked small and predatory invertebrates, especially in the dry season. The 1989 plot was intermediate in invertebrate abundance and diversity. The use of partially deciduous trees in the 1989 and 1990 plots, resulting in lower canopy cover at the driest time of the year, may have contributed significantly to the differences found between the early and later plantings. It is recommended that trees that provide good canopy cover year‐round be used as dominant species in plantings to facilitate the development of a leaf litter ecosystem that can be sustained throughout the year.
Reforestation of Bottomland Hardwoods and the Issue of Woody Species Diversity
Authors: Allen James A.
Published: July 2003

Bottomland hardwood forests in the southcentral United States have been cleared extensively for agriculture, and many of the remaining forests are fragmented and degraded. During the last decade, however, approximately 75,000 ha of land—mainly agricultural fields—have been replanted or contracted for replanting, with many more acres likely to be reforested in the near future. The approach used in most reforestation projects to date has been to plant one to three overstory tree species, usually Quercus spp. (oaks), and to rely on natural dispersal for the establishment of other woody species. I critique this practice by two means. First, a brief literature review demonstrates that moderately high woody species diversity occurs in natural bottomland hardwood forests in the region. This review, which relates diversity to site characteristics, serves as a basis for comparison with stands established by means of current reforestation practices. Second, I reevaluate data on the invasion of woody species from an earlier study of 10 reforestation projects in Mississippi, with the goal of assessing the likelihood that stands with high woody species diversity will develop. I show that natural invasion cannot always be counted on to produce a diverse stand, particularly on sites more than about 60 m from an existing forest edge. I then make several recommendations for altering current reforestation practices in order to establish stands with greater woody species diversity, a more natural appearance, and a more positive environmental impact at scales larger than individual sites.
Using Tidal Salt Marsh Mesocosms to Aid Wetland Restoration
Authors: Callaway John C. , Zedler Joy B. , Ross Donna L.
Published: July 2003

Tidal wetland mesocosms at Tijuana River National Estuarine Research Reserve failed to elucidate effects of hydrologic treatments (excluded, impounded, and fully tidal systems) for most parameters measuring Salicornia virginica (pickleweed). Although soil salinity increased where tidal flushing was excluded for 10 months (salinities rose ∼20 to 50%), pickleweed cover and algal chlorophyll did not differ among treatments. Effects were seen only in pickleweed growth rates (∼30% decrease where tides were excluded) and normalized difference vegetation index (NDVI) measurements. We failed to show any differences between impounded and fully tidal conditions, because the mesocosms had coarse sediments, and impounded water drained easily via subsurface flow. However, the problems that we encountered with the mesocosms led to the following advice for future wetland restoration projects: (1) Mesocosms are useful for testing restoration techniques before an actual restoration project takes place. (2) Mesocosms should be used to test factors that may lead to more successful restoration in the future, including planting techniques, substrate conditions, and hydrology. (3) Mesocosms should be used to develop new assessment methods for monitoring wetland ecosystems. Because of the ability to control some environmental parameters while maintaining seminatural conditions, mesocosms offer great potential for the future evaluation of experimental restoration techniques.
Native Colonizing Species and Degraded Land Restoration in La Gran Sabana, Venezuela
Authors: Rosales J. , Cuenca G. , Ramírez N. , De Andrade Z.
Published: July 2003

We evaluated the ecological and reproductive characteristics of plant species occurring in severely disturbed areas that were revegetated with exotic grasses. We identified those species with the best combination of attributes that increase their probability of success in degraded lands. Fifteen degraded areas were studied in two different bioclimatic regions, a high premontane humid bioclimate and a low premontane humid bioclimate. The frequency of native colonizing species and the presence of arbuscular mycorrhizal colonization in their roots were evaluated. The sexual and breeding system, pollination mode, fruit set, and dispersal syndrome of ten of the most frequent colonizing species were also studied. The floristic survey of the colonizing species revealed a similarity to the reported flora of the treeless savannas that are dominant in the region. Bioclimatic conditions prevailing in the degraded lands seem to be an important factor for the presence of colonizing species and for species richness. All colonizing species studied were mycorrhizal, and for this reason the restoration program in these degraded areas should take mycorrhizae into account, reintroducing them or manipulating the soils to increase the mycorrhizal inoculum. We suggest Scleria cyperina and Trachypogon plumosus to start or promote the natural succession in the degraded areas from La Gran Sabana. Because their frequency is high and their reproductive system is less dependent on biotic factors, these species stand out in the studied areas.
Reestablishment of a Rodent Community in Restored Desert Scrub
Authors: Patten Michael A.
Published: July 2003

I conducted small‐mammal trapping surveys on a desert scrub restoration site in Palm Springs, California, to document concomitant recovery of the rodent community. These surveys were conducted following quantitative vegetation sampling efforts that indicated that a predefined successful restoration criterion of 15% total shrub cover had been met throughout most of the area. But shrub cover, native shrub cover, herb cover, native herb cover, total cover, and total native cover remained significantly lower in the restoration area than in undeveloped desert scrub immediately surrounding the site. Native herb species richness was also generally lower in the restoration area. Despite these vegetation differences, rodent diversity, evenness, and abundance were very similar between the restoration and natural areas (they were consistently slightly higher in the restoration area). More diverse microhabitats, proximity to water, and reduced competition with harvester ants may have contributed to this outcome. If ecosystem restoration is the goal, reestablishment of a faunal community in restored habitat, rather than surpassing a predefined percent cover of vegetation, may be a better indicator of success, because plant cover proved to be a poor predictor of mammal success.