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.
The thermal histories of archeological cereal grains were examined by electron spin resonance spectroscopy. Studies with modern samples of heated cereal grain showed that the parameters of the electron spin resonance signal characterize the maximum temperature to which the sample had previously been heated. This technique has applicability in archeology and other disciplines. 相似文献
Morphological characterisation and agronomic evaluation was conducted on 12 transgenic broccolilines containing a tomato antisense1-aminocyclopropane-1-carboxylic
acid (ACC) oxidase gene. Plants of three cultivars: Shogun (Sh), Green Beauty (Gy) and Dominator (D), were regenerated from
hairy root cultures after co-cultivation with Agrobacterium rhizogenes strain A4T harbouring the binary vector pLN35. The T-DNA of pLN35 contains genes encoding a tomato antisense ACC oxidase
gene (35S-ACC-5′7′) and a neomycin phosphotransferase II gene (NOS-NPTII-NOS) for kanamycin resistance. The transgenic plants
were transferred to a greenhouse and fertile plants obtained. Integration of the foreign DNA into the broccoli genome was
confirmed by the polymerase chain reaction and Southern analyses. Transgenic plants showed evidence of hairy root (HR)-induced
morphological changes to varying degrees. Of the 12 characterised transgenic lines, three lines(Gy/7, D/1 and D/2) performed
within the limits of acceptability for all head quality parameters analysed (size, density, colour, shape and leafiness).
The ethylene production from stalks of four field-grown transgenic lines of Green Beauty broccoli showed significant reductions
in activity relative to the control 98 h after harvest. The Dominator transgenic lines D/1 and D/2 showed significant improvements
in head colour relative to the control from 48 h after harvest. These results are consistent with the ethylene production
patterns determined previously for these lines. The head colour results are consistent with previous results suggesting that
two enzyme systems may be involved in broccoli senescence, giving two bursts of ethylene production, with only the second
burst inhibited by the antisense ACC oxidase gene used.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
Acute tubulo-interstitial nephritis was diagnosed post mortem when a dog died four days after surgery for a femoral head resection. Possible causative factors associated with halothane anaesthesia, flunixin meglumine analgesia and prophylactic antibiotic therapy with trimethoprim-sulphadiazine are discussed. It is concluded that death was due to renal failure associated with tubulo-interstitial nephritis as a result of a combination of ischaemic and toxic events. 相似文献
Generally obese and lean pigs in both the fed and fasted states were anesthetized and then acutely infused with increasing concentrations of the beta-adrenergic agonist isoproterenol. Plasma free fatty acid (FFA), blood glycerol, glucose and lactate, and heart rate were monitored during the infusion period. Data were reduced by estimating the parameters of the generalized logistic function (minimum, maximum, ED50 and slope) and subsequently analyzed to compare the lean and obese genotypes within nutritional state. Lactate data could not be fitted to this function because the upper asymptote was not approached during the experiment. The minimum plasma concentration of FFA tended (P less than .1) to be less in obese than in lean pigs. The maximum, ED50 and slope for the responses of FFA were similar for obese and lean pigs in fed pigs and in fasted pigs. In fed pigs, the minimum glycerol concentration was greater in obese than in lean pigs, and the ED50 for heart rate tended to be lower in lean than in obese pigs. All other estimated parameters for the variables were similar in fed obese and lean pigs. In fasted pigs, the maximum glucose concentration was greater in obese than in lean pigs. All other parameters for the variables were similar in fasted obese and lean pigs. The results suggest that there was no major defect in lipid mobilization in these obese pigs (only a lower minimum FFA concentration was detected) and that an increased maximum blood glucose concentration in the fasting state might contribute to the obesity. 相似文献
A seven-year-old Labrador was presented with weight loss and mild generalised lymphadenopathy. Histopathology of an excised lymph node by the referring veterinarian demonstrated granulomatous lymphadenitis. At the time of referral, fine-needle aspirates of the lymph nodes confirmed the presence of ongoing granulomatous inflammation. Further investigations revealed marked hypercalcaemia, a low parathyroid hormone concentration, a parathyroid hormone related protein concentration within the reference range, and an elevated serum concentration of 1,25 dihydroxyvitamin D. An underlying cause of the granulomatous lymphadenitis could not be identified. The clinical signs, hypercalcaemia and elevated serum concentrations of 1,25 dihydroxyvitamin D resolved following prednisolone treatment. In contrast to dogs, hypercalcaemia occurred secondarily to granulomatous disease and elevated 1,25 dihydroxyvitamin D concentrations is a well-recognised condition in human beings. To the authors' knowledge, this is the first case report to describe elevated serum calcium and 1,25 dihydroxyvitamin D concentrations in a dog with histologically confirmed granulomatous disease. 相似文献