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Does conservation planning matter in a dynamic and uncertain world? 总被引:10,自引:0,他引:10
Loss of biodiversity is one of the world's overriding environmental challenges. Reducing those losses by creating reserve networks is a cornerstone of global conservation and resource management. Historically, assembly of reserve networks has been ad hoc, but recently the focus has shifted to identifying optimal reserve networks. We show that while comprehensive reserve network design is best when the entire network can be implemented immediately, when conservation investments must be staged over years, such solutions actually may be sub‐optimal in the context of biodiversity loss and uncertainty. Simple decision rules, such as protecting the available site with the highest irreplaceability or with the highest species richness, may be more effective when implementation occurs over many years. 相似文献
774.
Ziqi Zhu Han Wang Sandy P. Harrison Iain Colin Prentice Shengchao Qiao Shen Tan 《Global Change Biology》2023,29(1):126-142
Recent increases in vegetation greenness over much of the world reflect increasing CO2 globally and warming in cold areas. However, the strength of the response to both CO2 and warming in those areas appears to be declining for unclear reasons, contributing to large uncertainties in predicting how vegetation will respond to future global changes. Here, we investigated the changes of satellite-observed peak season absorbed photosynthetically active radiation (Fmax) on the Tibetan Plateau between 1982 and 2016. Although climate trends are similar across the Plateau, we identified robust divergent responses (a greening of 0.31 ± 0.14% year−1 in drier regions and a browning of 0.12 ± 0.08% year−1 in wetter regions). Using an eco-evolutionary optimality (EEO) concept of plant acclimation/adaptation, we propose a parsimonious modelling framework that quantitatively explains these changes in terms of water and energy limitations. Our model captured the variations in Fmax with a correlation coefficient (r) of .76 and a root mean squared error of .12 and predicted the divergent trends of greening (0.32 ± 0.19% year−1) and browning (0.07 ± 0.06% year−1). We also predicted the observed reduced sensitivities of Fmax to precipitation and temperature. The model allows us to explain these changes: Enhanced growing season cumulative radiation has opposite effects on water use and energy uptake. Increased precipitation has an overwhelmingly positive effect in drier regions, whereas warming reduces Fmax in wetter regions by increasing the cost of building and maintaining leaf area. Rising CO2 stimulates vegetation growth by enhancing water-use efficiency, but its effect on photosynthesis saturates. The large decrease in the sensitivity of vegetation to climate reflects a shift from water to energy limitation. Our study demonstrates the potential of EEO approaches to reveal the mechanisms underlying recent trends in vegetation greenness and provides further insight into the response of alpine ecosystems to ongoing climate change. 相似文献
775.
Ashlin Munsamy R. Stuart Rutherford Sandy J. Snyman M. Paula Watt 《Plant biotechnology reports》2013,7(4):489-502
A possible strategy to produce variant sugarcane plants with beneficial traits was tested by promoting somaclonal variation in vitro through the action of the hypomethylation and mutagenic agent 5-Azacytidine (Azac). Treatment of calli in liquid medium caused high levels of necrosis. Consequently, 6- to 8-week-old calli of cultivar NCo376 were exposed to 50 and 100 μM Azac in semi-solid callus induction medium (CIM) (MS salts and vitamins, sucrose, casein hydrolysate, agar, with or without 3 mg l?1 2,4-D) for 1 week. They were then transferred to fresh CIM with 2,4-D and to CIM without 2,4-D, for 2 and 8–10 weeks, respectively. The highest callus necrosis (>60 %) and reduced recovery (<40 %) were recorded for calli treated with 100 μM Azac without 2,4-D, which also resulted in lower plant yield (12 plantlets/0.2 g calli) than the control (18 plantlets/0.2 g calli). From methylation-sensitive amplified fragment length polymorphism analyses, the highest polymorphisms (4.2 %) were also obtained from plants derived from the 100 μM Azac treatment without 2,4-D. After 9 months of field growth, Azac-derived plants exhibited phenotypic differences compared with the controls. Ex vitro screening resulted in the identification of one plant from the 100 μM Azac with 2,4-D treatment putatively tolerant to smut, and three plants from the 100 μM Azac with 2,4-D and one from the 50 μM Azac with 2,4-D treatments, potentially tolerant to the herbicide imazapyr. 相似文献
776.
John D. Sandy Heather L.G. Brown D.A. Lowther 《Biochimica et Biophysica Acta (BBA)/General Subjects》1978,543(4):536-544
Adult rabbit articular cartilage was labelled in vivo over 48 h with [35S]sulphate and was then incubated in organ culture at pH 7.2. Approx. 65% of the tissue content of [35S]proteoglycan was released into the culture medium during the first 48 h of incubation. The average molecular size of the released proteoglycans, as assessed by fractionation on Sepharose 2B/CL and 4B/Cl, was only slightly smaller than that of the proteoglycans extracted from non-cultured cartilage with 4 M guanidine HCl. The percentage of released proteoglycans and extracted proteoglycans which formed aggregates with hyaluronic acid was approx. 25% and 75%, respectively. The results indicate that proteoglycan degradation in adult articular cartilage is initiated by a limited proteolysis of subunit core protein, with the [roduction of non-aggregating species which diffuse readily from the tissue. 相似文献
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Diógenes Infante Sandy Molina Jhonny R. Demey Elizabeth Gámez 《Plant Molecular Biology Reporter》2006,24(2):205-217
Agaves are succulent monocot plants rich in fibers, sugars and other important compounds. They are also valued as ornamental
plants and for their ability to grow in poor soils. In the present study, inverse sequence-tagged repeats (ISTR) and amplified
fragment length polymorphism (AFLP) analysis were used to study genetic diversity in differentAgavaceae plant samples. Comparison of the banding patterns between the mother plant and rhizome-derived daughter plants showed that
genetic variability is generated during asexual reproduction in these species. Phylogenetic relationships amongAgave species were obtained using unweighted pair-group method, arithmetic average (UPGMA) analysis. Genetic diversity through
asexual propagation allows for genetic selection and improvement within these asexually propagated plants. 相似文献
779.
Differential effects of phorbol ester (PMA) on blocker-sensitive ENaCs of frog skin and A6 epithelia
Els Willem J.; Liu Xuehong; Helman Sandy I. 《American journal of physiology. Cell physiology》1998,275(1):C120
Activation ofprotein kinase C with phorbol 12-myristate 13-acetate (PMA) causedcomplex transient perturbations of amiloride-sensitive short-circuitNa+ currents(INa) in A6epithelia and frog skins that were tissue and concentration dependent.A noninvasive channel blocker pulse method of noise analysis (18) wasused to investigate how PMA caused time-dependent changes of apicalmembrane epithelial Na+ channel(ENaC) single-channel currents, channel open probabilities (Po), andchannel densities(NT). In A6epithelia, 5 and 50 nM PMA caused within 7 min concentration-dependentsustained decreases ofPo (~55% belowcontrol, 50 nM) and rapid compensatory transient increases ofNT within 7 min(~220% above control, 50 nM), resulting in either small transientincreases of INaat 5 nM PMA or small biphasic decreases ofINa at 50 nM PMA.In contrast to A6 epithelia, 50 and 500 nM PMA in frog skin causedafter a delay of at least 10 min transient increases ofNT to~60-70% above control at 30-60 min. Unlike A6 epithelia,Po was increased~15% above control within 7 min and remained within±10-15% of control for the duration of the 2-h experiments.Despite differences in the time courses of secondary inhibition oftransport in A6 epithelia and frog skin, the delayed downregulation oftransport was due to time-dependent decreases ofNT from theirpreelevated levels in both tissues. WhereasPo is decreasedwithin minutes in A6 epithelia as measured by noise analysis or bypatch clamp (8), the discrepancy in regulation ofNT in A6epithelia as measured by noise analysis and patch clamp is most likelyexplained by the inability of on-cell patches formed before treatmentof tissues with PMA to respond to regulation of their channeldensities. 相似文献