The value of linking paleoecological and neoecological perspectives to understand spatially-explicit ecosystem resilience     

Buma  B.  Harvey  B. J.  Gavin  D. G.  Kelly  R.  Loboda  T.  McNeil  B. E.  Marlon  J. R.  Meddens  A. J. H.  Morris  J. L.  Raffa  K. F.  Shuman  B.  Smithwick  E. A. H.  McLauchlan  K. K. 《Landscape Ecology》2019,34(1):17-33

Context

Predicting ecosystem resilience is a challenge, especially as climate change alters disturbance regimes and conditions for recovery. Recent research has highlighted the importance of spatially-explicit disturbance and resilience processes to long-term ecosystem dynamics. “Neoecological” approaches characterize resilience mechanisms at relatively fine spatio-temporal resolutions, but results are difficult to extrapolate across broad temporal scales or climatic ranges. Paleoecological methodologies can consider the effects of climates that differ from today. However, they are often limited to coarse-grained spatio-temporal resolutions.

Methods

In this synthesis, we describe implicit and explicit examples of studies that incorporate both neo- and paleoecological approaches. We propose ways to build on the strengths of both approaches in an explicit and proactive fashion.

Results

Linking the two approaches is a powerful way to surpass their respective limitations. Aligning spatial scales is critical: Paleoecological sampling design should incorporate knowledge of the spatial characteristics of the disturbance process, and neoecological studies benefit from a longer-term context to their conclusions. In some cases, modeling can incorporate non-spatial data from paleoecological records or emerging spatial paleo-data networks with mechanistic disturbance/recovery processes that operate at fine spatiotemporal scales.

Conclusions

Linking these two complementary approaches is a powerful way to build a complete understanding of ecosystem disturbance and resilience.

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Exploiting chemical ecology to manage hyperparasitoids in biological control of arthropod pests     

Antonino Cusumano  Jeffrey A Harvey  Mitchel E Bourne  Erik H Poelman  Jetske G de Boer 《Pest management science》2020,76(2):432-443

Insect hyperparasitoids are fourth trophic level organisms that commonly occur in terrestrial food webs, yet they are relatively understudied. These top‐carnivores can disrupt biological pest control by suppressing the populations of their parasitoid hosts, leading to pest outbreaks, especially in confined environments such as greenhouses where augmentative biological control is used. There is no effective eco‐friendly strategy that can be used to control hyperparasitoids. Recent advances in the chemical ecology of hyperparasitoid foraging behavior have opened opportunities for manipulating these top‐carnivores in such a way that biological pest control becomes more efficient. We propose various infochemical‐based strategies to manage hyperparasitoids. We suggest that a push‐pull strategy could be a promising approach to ‘push’ hyperparasitoids away from their parasitoid hosts and ‘pull’ them into traps. Additionally, we discuss how infochemicals can be used to develop innovative tools improving biological pest control (i) to restrict accessibility of resources (e.g. sugars and alternative hosts) to primary parasitoid only or (ii) to monitor hyperparasitoid presence in the crop for early detection. We also identify important missing information in order to control hyperparasitoids and outline what research is needed to reach this goal. Testing the efficacy of synthetic infochemicals in confined environments is a crucial step towards the implementation of chemical ecology‐based approaches targeting hyperparasitoids. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

Effect of site preparation on survival and growth of Douglas-fir (Pseudotsuga menziessi Mirb. Franco.) seedlings     

Russell T. Graham  Alan E. Harvey  Martin F. Jurgensen 《New Forests》1989,3(1):89-98

The performance (survival and growth) of Douglas-fir (Pseudotsuga menziesii Mirb. Franco.) seedlings planted in minimally disturbed, scalped, and bedded soils, both with and without herbicidal control of weeds, were compared. Douglas-fir growing for 3 years in bedded soils treated with herbicide were heavier, taller, and had deeper root systems than trees growing in other preparations. Scalping did not improve seedling performance when compared to minimally disturbed soils. Soils rich in organic matter benefited tree growth. Competing vegetation in raised beds was detrimental to seedling performance.  相似文献   

Nutrition, xylem cavitation and drought resistance in hybrid poplar     

Harvey HP  Van Den Driessche R 《Tree physiology》1997,17(10):647-654

Effects of mineral nutrition on susceptibility to cavitation were examined in four hybrid poplar clones. Two drought-sensitive and two drought-resistant hybrid clones of black cottonwood (Populus trichocarpa Torr. & Gray) and eastern cottonwood (P. deltoides Bartr.) were grown at three concentrations of nitrogen (N) applied factorially with two concentrations of phosphorus (P) in a greenhouse, and subjected to varying degrees of drought stress before measurement of cavitation and of anatomical features that might affect cavitation. Mean vessel pit pore diameters were 0.132 micro m at low P, and 0.074 micro m at high P, but no other significant effects of mineral nutrition on vessel dimensions were observed. Vessel diameter and specific conductivity were greater in the drought-resistant clones than in the drought-susceptible clones. Drought-resistant clones did not reach such low water potentials as drought-sensitive clones during the cavitation induction experiments, suggesting better stomatal and cuticular control of water loss. Scanning electron microscope observations showed less damage to pit membranes, also suggesting greater membrane strength in drought-resistant clones than in drought-sensitive clones. High concentrations of N increased cavitation, whereas high concentrations of P decreased cavitation as measured by both hydraulic flow apparatus and dye perfusion techniques. For one test, cavitation was 48% at high N and low P, but only 28% at high N and high P. We consider that N fertilization may make poplars more susceptible to cavitation on dry sites, but P fertilization may reduce this effect.  相似文献   

From the editor     

Harvey S. James Jr. 《Agriculture and Human Values》2015,32(1):1-1

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From the editor     

Harvey S. James Jr. 《Agriculture and Human Values》2015,32(4):577-578

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Over-canopy saline sprinkler irrigation of grapevines during different growth stages     

Rob M. Stevens  Gordon Harvey  Scott Norton  William Frahn 《Agricultural Water Management》2011,101(1):62-70

Wetting plant foliage with saline irrigation increases the uptake of toxic ions Na⁺ and Cl⁻. Over three consecutive seasons, Colombard vines grafted on Ramsey rootstock were irrigated with saline water (EC 3.5 dS/m) by over-canopy sprinklers during any one of the first three of the four annual growth stages: bud burst to full bloom (treatment BB-FB), full bloom to veraison (treatment FB-V), and veraison to harvest (treatment V-H). At other times, vines received non-saline water (EC 0.5 dS/m) as did the control. Seasonal average soil salinities remained relatively constant over the trial. In contrast, the concentrations of Na⁺ and Cl⁻ in one-year old wood and grape juice more than doubled. In treatments FB-V and V-H the average yield over the three seasons was reduced by up to 15%. Results were compared with those obtained in an earlier study which was undertaken in the same vineyard with the same treatments applied via dripper. With drippers, the maximum reduction in the average yield over three seasons was 2%. Saline sprinkling caused rises in Na⁺ and Cl⁻ concentrations of fruit, leaf lamina and one-year-old wood that were at least 7-fold, 5-fold and 2-fold greater, respectively, than the rises caused by application of the same treatments with drip. Progressive seasonal rises in the concentrations of Na⁺ and Cl⁻ in these tissues were due in part to carryover of salt added in previous seasons; with saline sprinkling the magnitude of these carryovers was 4-fold greater than those with saline drip irrigation. With saline water, vignerons can reduce losses by using irrigation systems which do not wet the foliage.  相似文献   

Geographical ‘handicaps’ and small states: Some implications for the Pacific from a global perspective     

Harvey Armstrong  Robert Read 《Asia Pacific viewpoint》2006,47(1):79-92

Abstract: Research on the economic performance of small states has concentrated on the implications of small size and thin local markets. An interesting feature of many of the world's smallest states, of which the Pacific region has many, is that they face additional challenges than just small size. Many are remote from global markets for their products. In addition, a large number are also islands, many of which are also mountainous. Many of the smaller states are not just islands, but are also archipelagos. Hence in addition to small size, many of the world's small states also exhibit four other characteristics that may affect their economic performance: insularity, remoteness, being archipelagos and being highly mountainous entities. This paper examines the nature of the challenges posed by these four characteristics and seeks to produce empirical evidence of how difficult it has been to overcome these challenges. The paper draws on empirical evidence for 126 very small global states, dependent territories and highly autonomous regions. The paper then turns to the position of the Pacific small states and dependent territories.  相似文献   

The nature and inheritance of sweetness and acidity in the cultivated apple   总被引：2，自引：0，他引：2  

A. G. Brown  D. M. Harvey 《Euphytica》1971,20(1):68-80

Summary A survey was made of the sweetness and sourness of the fruits of apple cultivars. Measurements of the concentration of sugars and malic acid in ripe fruits were made and the variation between samples of a cultivar, between cultivars, between years and between cultivars and their tetraploid and colour sports was studied and showed a wide range of variation between cultivars but fairly constant values within cultivars.The study of a number of progenies shows that sweetness and sourness are inherited independently. Sweetness shows a quantitative pattern of inheritance and the progeny mean approximates the mid-parent value. Sourness is controlled by a single gene, with medium and high acidity being dominant to very low, superimposed on a quantitative pattern.The mean sugar and acid concentrations of a progeny and the approximate range of variation can be predicted from the sugar and acid concentrations found in the parents.  相似文献   

Challenging the developmental state: Nature conservation in Singapore     

Harvey Neo 《Asia Pacific viewpoint》2007,48(2):186-199

Abstract: Nature conservation efforts are often reactive to encroaching development plans and systematic conservation planning that is integral with development is not only uncommon, but is often fraught with difficulties even where it is actually attempted. Such obstacles to conservation are especially apparent in developmental states where state legitimacy is largely derived from the state's ability to develop the country. Among other things, developmental states place a premium on physical and economic development. This paper critiques, through the standpoint of nature conservation, the inadequate conceptualisation of ‘development’ in the developmental state thesis. Specifically, this paper argues that the seemingly value‐free (but ultimately economically based) underpinnings of development goals pushed by the developmental state needs to be tempered with a broader concern for the ethics of development. To that end, I draw on two case studies of nature conservation tussles in Singapore to show how alternative extra‐economic visions of development have been articulated, notwithstanding the developmental state's monopoly on the discourse (and practice) of progress and development. The case studies, set in the heady economic growth of the early 1990s, will critique two related aspects of the developmental state: its ‘amoral’ economistic conception of development and its use of growth and materialism as legitimacy.  相似文献