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翻译77：很多人觉得自己有必要赶时尚。
Many people think that it is important for them to keep pace with the latest trend.正确的句子：Many people consider it necessary to follow fashion.笔记：1、fashion为不可数名，follow fashion=keep up with fashion赶时尚；be in fashion很时髦；be out of fashion过时的2、consider it(形式宾语) + adj.+ to do sth.翻译78：经费削减让很多年轻人很难接受大学教育。
Cut of fees makes it difficult for many young people receive a university education.正确的句子：Budget cuts make it difficult for many young people to receive a college education. 笔记：1、cut为可数名词，Budget cuts经费削减2、receive a university/college education 接受大学教育，不能用tertiary3、cut down 表示砍树，砍掉某一部分4、Government funds/funding/grants政府经费5、大作文不建议用let/make sb. do sth.6、fees表示个人的费用，这里不合适7、accept表示主动的接受，receive表示被动的接受翻译79：有时候，很难去评估人类行为的环境代价。
Sometimes,it is hard to evaluate the evironment consequence of human activities.正确的句子：Sometimes, it is difficult to evaluate the environmental cost of human activies笔记：1、the environmental cost环境的代价，cost表示代价为可数名词2、human activies人类得行为，behaviour表示人类的暂时性活动（一般不用human behaviour）3、price只有表示价格的意思4、此处用evaluate或者assess都可以翻译80：在大城市有一些贫困的社区。
正视它和克服它英语作文Title: Facing It and Overcoming It。
Challenges are an inevitable part of life. Whether they come in the form of personal obstacles, professional setbacks, or societal issues, facing them head-on and finding ways to overcome them is crucial for personal growth and success. In this essay, we will explore the importance of acknowledging challenges, strategies for confronting them, and the rewards that come with overcoming them.First and foremost, it is essential to acknowledge the challenges we face. Ignoring or denying them only prolongs the problem and prevents us from finding solutions. By recognizing and accepting the existence of a challenge, we can begin to understand its nature and scope. This awareness is the first step towards overcoming it.Once we have acknowledged a challenge, the next step isto confront it directly. This may involve breaking the challenge down into smaller, more manageable tasks, or seeking support from others who have faced similar obstacles. It's important to approach the challenge with determination and resilience, knowing that setbacks are a natural part of the process. By taking proactive steps towards addressing the challenge, we gain a sense ofcontrol and agency over our circumstances.There are many strategies for overcoming challenges,and different approaches may work better for different situations. For example, when faced with a personalobstacle such as fear or self-doubt, practicing self-care and mindfulness techniques can help build resilience and inner strength. In contrast, when confronting aprofessional setback or a societal issue, strategic planning, collaboration, and advocacy may be more effective.Furthermore, it's crucial to remember that overcoming challenges is not a solitary endeavor. Seeking support from friends, family, mentors, or professional networks can provide invaluable guidance, encouragement, and perspective.Additionally, sharing our experiences with others canfoster a sense of solidarity and inspire others to confront their own challenges.The journey of overcoming challenges is not always easy, but the rewards are well worth the effort. Each obstacle we overcome strengthens our resilience, builds character, and expands our capabilities. Moreover, overcoming challenges often leads to personal growth and self-discovery, as we learn more about our strengths, weaknesses, and values.In conclusion, facing challenges and finding ways to overcome them is an integral part of the human experience. By acknowledging challenges, confronting them directly, and seeking support when needed, we can navigate life's obstacles with resilience and determination. Ultimately,the process of overcoming challenges not only leads to personal growth and success but also strengthens our senseof purpose and resilience in the face of future adversity.。
小学下册英语第2单元测验卷(含答案)英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.The capital of Japan is __________.2.Iron reacts with oxygen to form _______.3.The teacher is _____ (kind/strict) to us.4. A shooting star is actually a _______ that burns up in the atmosphere.5.The chemical symbol for francium is ______.6.My ______ loves to explore new technologies.7.I can use it to ______ (动词) new games. Sometimes, I pretend it is a ______ (角色).8.My dad loves __________ (历史) and shares stories with us.9.The ________ is a famous painting by Leonardo da Vinci.10.The Earth’s shape is not a perfect sphere; it is an ______.11.The _____ (种子) will grow into a new plant.12.The __________ is a famous beach destination in Florida. (迈阿密)13.The penguin is a flightless ______ (鸟) that swims well.14.I enjoy ______ with my friends at the mall. (hanging out)15.The __________ (洞穴) is dark and mysterious.16.I see a ___ (cloud/sky) above.17.The rabbit is ___ (nibbling) on some grass.18.My favorite food is _______.19.I can ________ my toys.20.The country known for its pyramids is ________ (埃及).21.The children are _____ in the classroom. (quiet)22._____ (环境) plays a big role in plant health.23. A __________ is a region known for its cultural heritage.24.The _______ (小狐狸) is quick and clever.25.Chemical engineering involves applying principles of chemistry to design processes for producing _____.26.I like to _____ (捡) shells.27.The chemical symbol for chlorine is __________.28.My grandparents love to ____.29.We need to ___ (clean) our room.30.On weekends, we often visit the _________ (玩具店) to look for new _________ (玩具).31.The chemical formula for ethanol is _____.32.The __________ is a zone of contact between two different rock types.33.Hydraulic systems use fluids to transmit ______.34.What is the name of the longest river in the world?A. AmazonB. NileC. MississippiD. Yangtze答案:B35.My favorite _________ (玩具) teaches me about science.36.We are learning about ___. (plants, eats, sleeps)37.The kitten plays with a _________. (球)38.What is the name of the process plants use to make food from sunlight?A. RespirationB. PhotosynthesisC. FermentationD. Decomposition答案:B39.I see a _____ (狮子) at the zoo.40.The _____ (花期) varies among different plants.41.The __________ (历史的图景) paints a broad picture.42. A ____(community newsletter) informs residents of events and resources.43.Mars has the largest volcano in the ______.44.The city of Honiara is the capital of _______.45.biogeography) studies the distribution of species. The ____46._____ (种植) vegetables is rewarding and fun.47.What is the opposite of "hot"?A. WarmB. CoolC. ColdD. Scorching答案: C48.My friend is a _____ (摄影师) who captures moments.49. A cat's whiskers help it sense ______ (环境).50.The chemical formula for copper(I) oxide is _____.51.Mulching helps to retain ______ in the soil. (覆盖物有助于保持土壤中的水分。
小学上册英语第二单元真题(含答案)英语试题一、综合题(本题有50小题，每小题1分，共100分.每小题不选、错误，均不给分)1 The __________ (历史的启发) can motivate change.2 A squirrel gathers _______ for the winter season.3 My dad tells me ______ stories.4 What is 7 + 3?A. 9B. 10C. 11D. 12答案:B. 105 What is the capital of Nicaragua?A. ManaguaB. LeónC. GranadaD. Masaya答案:A6 The ______ (种子发芽) process requires optimal conditions.7 Every planet in our solar system orbits the ______.8 The puppy is _______ (在玩玩具).9 What is the sum of 5 + 6?A. 10B. 11C. 12D. 13答案:B10 Which instrument has keys and is played with fingers?A. GuitarB. DrumsC. PianoD. Violin答案:C11 The __________ (历史的深度理解) enriches our knowledge.12 What do we call the act of analyzing information?A. EvaluatingB. AssessingC. ReviewingD. All of the Above答案：D13 The chemical symbol for actinium is _____.14 She has a beautiful ________.15 The _____ (kiwi) is a fruit.16 The chemical formula for ammonium thiocyanate is __________.17 A wren is a small ______ (鸟).18 I like to eat ______ (fruit) salads.19 The _______ (New Deal) was a series of programs to combat the Great Depression.20 policy brief) summarizes recommendations for action. The ____21 I want to _______ (学习)如何演讲。
As a high school student with a keen interest in the sciences, Ive often found myself marveling at the brilliance of scientists who have shaped our world. However, its not just their groundbreaking discoveries that fascinate me, but also the unique character traits that both propel them to greatness and sometimes lead to their downfall. While the public often sees the triumphs of these scientific titans, its important to recognize that they, like all humans, have their flaws.One of the most common traits among scientists is their intense focus and dedication to their work. This singleminded pursuit of knowledge can be a doubleedged sword. On one hand, it allows them to delve deeply into their research, making groundbreaking discoveries that can change the course of history. But on the other hand, this obsession can lead to a neglect of other aspects of life. Personal relationships, social interactions, and even selfcare can suffer as a result of their relentless drive to uncover the mysteries of the universe.Take, for instance, the case of Isaac Newton, a towering figure in the scientific community. His contributions to physics and mathematics are unparalleled, but his personal life was fraught with conflicts and isolation. His intense focus on his work led to a life that was, by many accounts, lonely and filled with disputes with his contemporaries. This is not to say that all scientists are destined for a life of solitude, but it does highlight a potential pitfall of their character.Another common trait among scientists is their stubbornness, which can sometimes border on inflexibility. This trait can be beneficial when itcomes to defending a wellreasoned hypothesis against all odds. However, it can also lead to a refusal to accept new evidence that contradicts their established beliefs. A classic example of this is the story of Alfred Wegener, the father of the theory of continental drift. Despite his innovative ideas, he faced significant resistance from the scientific community, largely due to the rigid mindset of his peers who were unwilling to entertain the possibility of his theory being correct.Moreover, the meticulous nature of scientific work can sometimes lead to an overemphasis on detail, causing scientists to miss the bigger picture. This can result in a lack of creativity and an inability to think outside the box. While the scientific method relies heavily on evidence and logical reasoning, its also important for scientists to maintain a level of curiosity and openmindedness that allows them to explore new ideas and possibilities.In addition, the competitive nature of the scientific field can sometimes foster a sense of elitism among scientists. This can lead to a disregard for the opinions and contributions of others, particularly those outside of their specific area of expertise. This attitude can stifle collaboration and hinder the advancement of knowledge, as it closes off potential avenues of exploration and innovation.Its also worth noting that the pressure to publish and secure funding can sometimes lead scientists to cut corners or even engage in unethical practices. The desire to be the first to make a significant discovery can overshadow the importance of integrity in research. While this is not a flawinherent to all scientists, it is a potential pitfall that can tarnish the reputation of the scientific community as a whole.In conclusion, while the character of scientists is often celebrated for its positive traits such as curiosity, dedication, and intelligence, its important to acknowledge the potential downsides as well. The intense focus, stubbornness, meticulousness, elitism, and the pressures of the scientific community can sometimes lead to negative outcomes. As a student looking to the future, I am inspired by the achievements of scientists but also mindful of the need to balance these traits with a broader perspective, collaboration, and ethical conduct.。
Acacia mangium is a fast-growing tree species native to Australia, Indonesia and Papua New Guinea. It is widely planted in the tropics and subtropics for its valuable wood and other uses. In this article, we will provide aprehensiveparison of the characteristics of Acacia mangium in both English and Chinese, to facilitate a better understanding of this species.1. Scientific Name- English: Acacia mangium- Chinese: 盐肤木2. Description- English: Acacia mangium is a large tree that can grow up to 30-35 meters in height, with a str本人ght trunk and a broad, spreading crown. The bark is dark grey and fissured, and the leaves are bipinnate, with 5-8 p本人rs of pinnae and 20-40 p本人rs of leaflets.- Chinese: 盐肤木是一种高大的树木，最高可长到30-35米，树干笔直，树冠广阔。
树皮呈深灰色并有裂纹，叶子为二回羽状复叶，有5-8对小羽片和20-40对小叶片。
3. Wood Characteristics- English: The wood of Acacia mangium is highly valued for itsstrength, durability, and resistance to decay. It is used in a wide range of applications, including construction, furniture, and paper production.- Chinese: 盐肤木的木材以其强度、耐久性和抗腐蚀性而备受青睐。
Time is an invaluable resource that we all share.It is the currency of life,and how we choose to spend it determines the value of our existence.In this essay,we will explore the significance of time,its management,and the impact it has on our lives.The Value of TimeTime is often referred to as the most precious commodity because it is finite.Once a moment has passed,it can never be regained.This is why it is crucial to value every second,minute,and hour.The saying time is money is a metaphor that emphasizes the importance of using time efficiently.In reality,time is even more valuable than money because money can be earned back,but time cannot.The Concept of Time ManagementEffective time management is the key to achieving more in less time.It involves organizing and planning how to devote time to different activities to increase productivity and effectiveness.Good time management skills can lead to a balanced life,reducing stress and increasing satisfaction.It requires setting priorities,creating schedules,and avoiding procrastination.The Impact of Time on Personal GrowthTime is also a critical factor in personal development.It allows individuals to learn,grow, and evolve.The more time one invests in selfimprovement,the more they can achieve. For students,time is essential for studying,practicing,and mastering new skills.For professionals,it is crucial for career advancement and skill development.The Role of Time in RelationshipsIn our personal lives,time plays a significant role in building and maintaining relationships.Quality time spent with family and friends strengthens bonds and creates lasting memories.However,the lack of time can lead to strained relationships and missed opportunities for connection.Cultural Perspectives on TimeDifferent cultures have different perceptions of time.Some view time as linear and rigid, while others see it as cyclical and flexible.Understanding these cultural differences is essential for effective communication and collaboration in a globalized world.The Future and TimeAs we look to the future,the concept of time continues to evolve.With advancements in technology,we are finding new ways to measure and utilize time.However,the fundamental truth remains:time is limited,and how we choose to spend it will shape our future.ConclusionIn conclusion,time is a nonrenewable resource that should be respected and wisely utilized.It is the foundation upon which we build our lives,and it is up to each individual to make the most of the time they have.By understanding the value of time,practicing effective time management,and appreciating its impact on personal growth,relationships, and cultural perspectives,we can lead more fulfilling and successful lives.。
housing and in share prices,the massive loss of jobs,and the slowing of economic growth.It thus includes the global recession and sovereign debt crisis that continue,and threaten to lead to stagflation.This short article has three objectives.First,it will outline what constitutes ethical conduct by business.Second,it will suggest why finance seems so often to be associated with unethical conduct.And third,it will identify what conduct leading to and responding to the Global Financial Crisis was indeed morally wrong.The conceptual and philosophical approach of this article is thus substantially different from most responses to the crisis,whose focus has instead been macroeconomic analysis,institutional design 2,and/or public policy,especially deregulation.3Even commentators ostensibly dealing with ethics have characteristically just condemned greed (e.g.Tett 2009;Lewis et al.2010),or deplored the absence of integrity.4This article,in contrast,attempts to offer an analytical framework for identifying exactly what was unethical,and why it was.2.Business ethics properly understoodTo understand what constitutes ethical conduct by business,one must first understand what business is.Properly identifying the purpose of business is vital,because the values of business ethics are just those that must be respected for the business purpose to be possible.The specific objective that is unique to business,and that distinguishes business from everything else,is maximising owner (financial)value over the long term by selling goods or services 5.Long-term views require operating over time,and thus confidence in a future.Confidence requires trust,so the conditions of trust must be observed:lying,cheating and stealing are therefore ruled out.Equally,owner value presupposes ownership and therefore respect for property rights.In order not to be ultimately self-defeating,business must be conducted with honesty and fairness,and without physical violence or coercion.Collectively,these constraints embody what may be called ‘Ordinary Decency ’.Furthermore,business that is directed at achieving its definitive purpose encouragescontributions to that purpose,and not to some other;classical ‘Distributive Justice ’is alsoessential.Just as Ordinary Decency is distinct from vague notions of ‘niceness’,this concept of justice has nothing to do with modern attempts to redistribute wealth on ideological grounds.What Distributive Justice requires is simply that within an organisation,contributions to the organisational objective be the basis for distributing organisational rewards.Though the term ‘Distributive Justice’may be unfamiliar,the underlying concept is widely recognised.It is implicit in the commonly accepted view that productive workers deserve more than shirkers;when properly structured,both performance-related pay and promotion on merit areexpressions of Distributive Justice.The key to Realist business ethics is very simple:business is ethical when it maximiseslong-term owner value subject to Distributive Justice and Ordinary Decency.If an organisation is not directed at maximising long-term owner value,it is not a business;if it does not pursue that definitive business purpose with Distributive Justice and Ordinary Decency,it is not ethical.3.The prominence of financial problemsIf business ethics is so straightforward,why do financial matters seem to present so many ethical problems?19economic affairs volume 33,number 120 e.sternbergOne key reason is the sheer pervasiveness offinance.Since all business dealings involvefinance,so do most business problems–including business’s ethical problems.Finance is not exceptionally problematical,but it is,in business,virtually inescapable;everything a business does hasfinancial ramifications.Finance also suffers from many of the same features that make business itself seem ethically suspect.It is the locus of decisions that can involve vast sums and equally strong temptations,and its practitioners are often presumed to be clever manipulators of money and of men.And sadly,some prominent examples offinancial loss have indeed been the consequence of moral wrongdoing,of deceit and outright theft.6Even in such cases, however,the misconduct is typically reflected infinance;it is not intrinsic tofinance.Major business scandals tend to be associated withfinance,because they are associated with financial losses.But it would be wrong to conclude either thatfinancial wrongdoing is the cause of those losses,or thatfinance is especially unethical.Businesses–including banks–typically lose money because their products or their marketing are misjudged,or because their operations or their staff are badly managed.Such failures always havefinancial consequences, and are ordinarily expressed infinancial terms,but they are not themselvesfinancial shortcomings.Even whenfinancial problems are at fault,and businesses suffer from bad debts or mismatched funding or undercapitalisation,the failings involved are more often the result of folly than of fraud.Indeed,unethical conduct infinance may be as much a response tofinancial losses as a source of them;it is when businesses are weak that the temptation to falsify results may be the greatest.4.Bank conduct and the GFCWhat does this Realist understanding of ethical conduct by business,and of the place of ethics infinance,indicate aboutfinancial institutions?In what ways,if any,did they act unethically, and contribute to the GFC?Recall that according to conventional assessments,they were evil.According to one academic report,During the second half of2008...all major world markets...were devastated by the aftermath of unethical lending practices by major lending institutions....Prudence and ethics were pushed aside as greed overcame good judgment among mortgage lenders nationwide.(Lewis et al.2010,p.77)What exactly is it that they did wrong?4.1.GreedThefirst criticism that needs to be challenged is the suggestion that greed dominated all,and that its very presence rendered the associated acts immoral.Both claims are false.Greed is a motive,which undoubtedly did impel somefinanciers,and prompt some unethical conduct.But(even)financiers are motivated by all sorts of impulses other than greed:by peer pressure and pride,by fashion and laziness,by curiosity and by sincere wishes to exercise their creative talents and solve problems.Greed is in fact responsible for far fewer business actions,and a fortiori for fewer business evils,than is commonly supposed.Moreover,even to the extent that greed is the operative motive,it is a relatively clean one: cupidity is,in an important sense,self-correcting.Those who genuinely want to acquire andkeep wealth will avoid conduct,including unethical conduct,that reduces wealth;the amounts of money the greedy seek may be unlimited,but the ways of achieving wealth are not.Finally,and still more fundamentally,even when greed is the motive,it has no necessaryeffect on the ethics of the actions it induces:the moral status of an act is largely independent of the motive that prompts it.4.2.Acts vs.motivesA motive is that which induces someone to act.It often refers to the personal,usuallyemotional,satisfactions that a person may seek in pursuing the objectives that define activities 7;a motive can also characterise the way in which definitive objectives are pursued.That which is done ,however,the act that is actually achieved or accomplished,can usually be abstracted away from the doer’s motive and evaluated separately.The same morally good act can be done from all sorts of motives.A person can,forexample,save a child from drowning out of a love of children,or fear of being called a coward.He can do it because it is his job,or because it is his moral duty.He can do it out of hope for publicity or a spirit of protectiveness 8.He can even do it to spite the child’s murderous parents or to upset his rival lifeguards.Whatever the motive,however,a good act –that of saving a child’s life –has been performed.That would be true even had the lifesaver been wicked and his motives thoroughly vicious:had he pulled the floundering child out of the sea only because he wanted to kidnap it,the child would still have been saved from drowning.Similarly,inbusiness,morally correct acts can be undertaken for all sorts of reasons.A firm can offer equal pay for equal work in order to champion justice or undermine the unions or simply obey the law.The moral rightness of acts is perfectly compatible with the full range of motives –prudence and ruthless selfishness as well as duty and altruism.Similarly,all sorts of motives,even noble ones,can give rise to immoral acts;worthyintentions are no proof against ignorance or error or foolishness.Genuinely devoted to justice,and with the best will in the world,a jury may nonetheless send the wrong man to gaol and a manager may promote the wrong person.The moral quality of an act is not determined by the motive that inspires it.Acts motivated by greed are not necessarily immoral.4.3.Subprime mortgagesBut perhaps the problem highlighted by the Global Financial Crisis is that there is something wrong about particular financial instruments.Consider subprime mortgages.One of the difficulties that hinders the proper assessment of subprime mortgages,is ageneral lack of clarity as to what they are.‘Subprime mortgages’are more accurately called ‘subprime mortgage loans’.They are actually a combination of two things:a loan to purchase real estate,and a mortgage,or conditional conveyance of property as collateral for the loan.Colloquially,however,they are regarded as a unit,and referred to as ‘subprime mortgages’.There is,however,no generally accepted definition of what makes a mortgage loan‘subprime’.The (US)Federal Reserve Board,Federal Deposit Insurance Corporation (‘FDIC’),Office of Thrift Supervision,and Office of the Comptroller of the Currency (‘OCC’)generally categorise as ‘subprime’mortgages that are executed by borrowers whose FICO (Fair Isaac Credit Organization)credit scores are less than 660(OCC 2001,p.3);the US Department of21economic affairs volume 33,number 122 e.sternbergHousing and Urban Development(‘HUD’)and(sometimes)the OCC apply the specific designation‘subprime’only to the subset of those loans for which FICO scores are less than 620(OCC2009,p.11;HUD).The Federal National Mortgage Administration(‘FNMA’,‘Fannie Mae’),in contrast,classifies as subprime the mortgages it purchases from subprime originators; it is unclear what renders an originator subprime.Also often classified as‘subprime’are securities that are otherwise labelled‘Alt-A’.These are pools of mortgage loans whose terms are somehow deficient,because of the mortgages’high loan-to-value ratio,interest only payments,adjustable rates,and/or insufficient documentation.By mid2007,27million mortgages–c.50per cent of all US mortgages–were subprime or Alt-A(Wallison2011,p.451).What is not disputed about subprime mortgages is that they arefinancial instruments.As such,however,subprime mortgages are not the sorts of things that can themselves have a moral status:a subprime mortgage can no more be ethical or unethical than a spoon can or a thermometer.The proper objects of moral judgement are not artefacts,but people and their actions.What can be morally assessed are the uses to which objects are put;it is those evaluations that typically characterise objects derivatively and colloquially.Artefacts that are themselves morally neutral can be used in good or bad ways,to further good and bad ends;the same candlestick that provides light can be used as an aggressive weapon.Artefacts can also be good or bad ones of their kind,that is,well or badly able to serve their purposes.A good candlestick holds a candlefirmly in an upright position so that it sheds light;a bad candlestick lets candles droop and drip.Moral judgements concerning subprime mortgages properly relate to their uses and their design.As business instruments,loans are ethical if they are directed at maximising long-term owner value while respecting Distributive Justice and Ordinary Decency.A loan is most likely to maximise long-term owner value for its issuer if its funding is cost-effective,and if it gets repaid in full and on time.Timely and complete repayment are,in turn,most likely if the borrowers are carefully selected.When funds are lent for long periods,they typically need the additional security of collateral to offset their higher risk.A good mortgage loan is one backed by property whose sale would be sufficient to repay the lender promptly if the borrower defaulted on the interest or principal. Additional requirements for a mortgage or any other loan’s being ethical are that the methods used in generating and selling and distributing it be honest and fair,and involve no coercion.A bad loan is one that fails to satisfy any of these conceptual criteria.On what grounds,then,are subprime mortgages so often condemned?It cannot be that their inferior quality came as a surprise:like‘junk bonds’,subprime mortgages indicated their deficiencies in their very name.Nor can their moral status simply reflect their being substandard compared with ordinary,prime,mortgage loans.When subprime mortgages are properly structured,so that they are likely to get repaid profitably,in full and on time(as historically most were),they can still be good business.To compensate for the greater risk of default resulting from the inferior credit quality of the borrower,or from more complex terms, a good subprime mortgage typically bears higher rates of interest than better-quality loans, and more restrictive covenants.Nor can the problem with the subprimes be their supposed complexity.Loans with an adjustable rate of interest are commonplace for other sorts of borrowing(mercial loans,and credit cards),and are standard for non-US mortgages (including those in the UK).One hundred per cent mortgages and endowment mortgages (ones on which only interest is paid throughout the life of the loan,and the principal gets repaid by the maturation of a lifeinsurance policy)have also featured in the UK ...though they have been considered suitable mainly for the highest-quality borrowers.The problem with subprime mortgages also cannot be the fact that they were pooled into securities and sold,rather than having been kept by the originating institutions.Originally initiated by a government agency,the Federal Home Loan Mortgage Corporation (‘FreddieMac’),this practice has been condemned as ‘origination for distribution’.But what’s wrong with that?Most products (e.g.shoes,computers)are created with the expectation that they will be sold rather than kept by their producers.Nor does any special problem arise because the products distributed are financial instruments.There is a more than 40-year history ofnon-recourse securitised debt obligations based on,for example,car loans,credit card loans.They have been unproblematic,even though the vendors and purchasers of those securities equally had no responsibility for generating or monitoring the underlying,constituent loans.The reason that the subprime mortgages associated with the global financial crisis (for simplicity,‘GFC subprimes’)were so problematical,is that they were not properly structured.They failed to meet basic standards of prudent lending,and consequently suffered much higher rates of default than subprime loans had done historically.Unlike traditional mortgages,the GFC subprime mortgages were issued to borrowers whose credit quality was significantly lower even than that of previous subprime borrowers.In addition,the loans were typically structured without the protections that would normally have been included to compensate for less creditworthy borrowers.9‘Know your customer’is a basic banking principle.It is minimally prudent,in assessing whether large loans are likely to get repaid,to obtain basic information about the borrowers,and to demand evidence of their creditworthiness.Accordingly,loan applicants normally have to submit tax returns,personal and bank references,employment and residence histories,and other such documents,to supplement the information available from commercial credit scores and police reports.Such basic information was,however,seldom provided or even requested for recipients of GFC subprime mortgages.Indeed,so little evidence was there for many of those loans,that the borrowers were known colloquially as NINJAs:borrowers with No INcome,Jobs,or Assets.A further defect of the GFC subprimes is that the inadequacy of the borrowers’creditquality was not offset by the protections normally required in such ually,even prime borrowers are obliged to pay cash for a significant portion of the properties they purchase.Down payments normally serve two important purposes.They protect the lenderagainst declines in the value of the collateral that would result from falling property prices.And they constitute a stake that the borrower stands to lose if he defaults on the loan.Historically,down payments of at least 20per cent of the mortgaged property’s assessed value wererequired.But for many GFC subprime mortgages,no down payment at all was needed:those loans were for 100per cent of the property’s purchase price.By making it possible for people with little or no savings to acquire property,minimal down payments made home ownership accessible to many who might not previously have had the opportunity.But by not requiring purchasers to risk any of their funds,it also strongly encouraged speculation,and helped to intensify both the property price boom and the number of defaulters.23economic affairs volume 33,number 124 e.sternbergMortgage loans that are not properly structured and/or ones that are issued to borrowers with inadequate credit quality are very risky;there is a high probability that will not get repaid. To the extent thatfinancial institutions made such loans,they did indeed act unethically.What was unethical,however,was that they violated the requirement to maximise long-term owner value:the mortgage lenders were insufficiently businesslike.Generating defective products is seldom a good strategy for maximising owner value.Even if the defective product is sold off,and even if its purchaser has no recourse to the originator, a reputation for defective products is a serious business liability.Consider the damaging effect on Toyota sales and shares of fears that some of its models might haveflaws.Though subprime loans were not as life-threatening as stuck accelerators,they could be–and indeed have been–detrimental to the wealth of bankers and the lives of banks.Why would lenders issue them?5.Moral hazardsA key factor was the presence of moral hazards.A moral hazard exists‘when the rules of an institution provide a positive incentive to do the wrong thing’(Sternberg1994/2000,p.103). Unfortunately,moral hazards and perverse incentives pervade the Americanfinancial markets as a result of government regulation.One of the most basic is deposit insurance.Because depositors know that funds up to the FDIC limit10are guaranteed by the US government,they have no incentive to entrust their savings only to prudent banks,or to monitor the operations of the banks holding their savings. In turn,the banks receiving such deposits are afforded a one-way bet.They can apply the insured funds to risky ventures in hopes of achieving high gains,confident that any losses will be made up by the US government.A second moral hazard is provided by the government’s provision of mortgage insurance. To encourage lending to less qualified borrowers,the US government has long offered guarantees of mortgages through the Federal Housing Administration(‘FHA’).Banks need not be concerned about the borrowers’creditworthiness,because the government covers the losses of defaults.By2006the FHA was the largest insurer of mortgages in the world,having guaranteed34million mortgages since its creation in1934(HUD2006).A third moral hazard is provided by the government’s guarantees of the major mortgage funding institutions.Fannie Mae and Freddie Mac raise money through the bond markets at preferred rates that reflect their status as Government Sponsored ing that money,Fannie and Freddie buy mortgages from lending institutions,thus supplying lenders with the funds to continue making loans.Prior to the GFC,Fannie and Freddie were ostensibly private corporations.But it was widely–and accurately11–believed that they enjoyed government guarantees.Because Fannie and Freddie expected that any losses they sustained on the mortgages they bought would be covered by the federal government,they had little incentive to restrict their purchases to properly structured mortgages,or to monitor the mortgages they acquired.Supporting housing is also behind a fourth moral hazard:tax relief on mortgage interest. This policy makes borrowing more attractive than saving,and makes real estate more attractive than other investments.It thereby distorts the market for housing and all alternative investments.As a result,both the demand for houses and the price of houses are keptartificially high.Although these moral hazards significantly antedated the GFC,their effects wereexacerbated by a series of government regulations that further skewed lending decisions.These regulations,constituting a fifth moral hazard,aimed at promoting home ownership for minorities.To that end,they obliged lenders to make loans to riskier borrowers,or suffer serious penalties.Such hazardous regulation included the following (Pinto 2010):1.The Community Reinvestment Act (‘CRA’),signed by President Carter in October 1977,outlawed redlining,the practice of refusing mortgages to everyone in a designatedgeographical area,without regard to their individual creditworthiness.Individualassessment was considered unnecessary,because it was thought that ‘low-quality housing and high levels of unemployment and welfare dependency made local residentsunattractive as borrowers’(Butler 2009,p.53).The redlined neighbourhoods were typically poor,and often black or Hispanic.2.In 1991the Home Mortgage Disclosure Act (‘HMDA’)rules were strengthened to include a specific demand for racial equality.Rules in place since 1975had already forced lenders to provide detailed reports about the identities of their borrowers;compliance wasincreasingly monitored by government-funded ‘community’groups like the Association of Community Organizations for Reform Now (‘ACORN’).3.In 1992the Federal Reserve Bank of Boston published a manual specifying that ‘criteria that would normally reduce the chances of a loan being granted ...should not affectlending decisions’(Butler 2009,p.53).Among the criteria excluded were a mortgageapplicant’s lack of credit history,using loans or gifts as their mortgage deposit (FRBB 1992,p.14),and using unemployment benefits as their basis for income (FRBB 1992,p.15).4.Also in 1992,the mission of Fannie and Freddie was changed from providing liquidity to the mortgage markets,to ‘supporting affordable housing’.This political objective overrode any interest in financial prudence;their criteria for purchasing mortgage loans wereloosened accordingly.In 1999,HUD ruled that by 2001,the percentage of mortgages that Fannie and Freddie purchased in respect of loans for affordable housing had to increase to 50per cent (Holmes 1999).In 2004,the requirement was increased:by 2008,loans to ‘low-and moderate-income families and underserved communities’had to reach 56per cent (HUD 2004).Not surprisingly,in 2008Fannie and Freddie plunged into massivedeficit and collapsed ...despite being subject to 236government regulators (Butler 2009,p.55;Redwood 2008).5.In 1995,the Community Reinvestment Act regulations were amended (CRA 1995)to oblige lenders not just to avoid redlining,but alsoto ignore most of the traditional criteria of credit-worthiness in their loan decisions.Mortgagescould now be any multiple of income;a person’s saving history was irrelevant;applicants’income did not need to be verified;and participation in a credit counselling programme could be taken as proof of an applicant’s ability to manage a loan.Violation of CRA regulations could be a violation of equal opportunity laws producing exposure to actual damages plus punitive damages of$500,000....Under the CRA,if a lender wants to change its business operation in any way –merging with another bank,opening or closing branches,or developing new products –it mustconvince the regulators that it will continue to make sufficient loans to the government’s preferred groups of borrowers.(Butler 2009,pp.53–4)1225economic affairs volume 33,number 126 e.sternbergThe regulations above accompanied and exacerbated the progressive relaxation of standards exercised by the government housing agencies.FHA down payment requirements,for example, plummeted.On housing amounts over$25,000,they were90per cent in1970,but a mere5per cent in1980;only thefirst$25,000qualified for a3per cent down payment.By1990,however,if housing cost less than$50,000,the full amount was eligible for the3per cent down payment.(Monroe2001, p.46)Not surprisingly,the FHA,Fannie and Freddie routinely guarantee over85per cent of all new US mortgages(Economist2011).Damaging though these regulations and institutions were,an even more pervasive and destructive(sixth)moral hazard has been provided by lax monetary policy.Since2000,the US Fed has kept US interest rates artificially low,and thus perverted the signals that would have been given by freely determined prices.Because low interest rates made mortgages appear inexpensive,people bought houses rather than other items.The demand for houses caused real estate prices to boom.Those inflated prices in turn made using houses as collateral seem safer than it was,and encouraged banks to make still more mortgage loans.Because interest rates were so low,however,banks could only maintain their loan yields by lending to ever riskier borrowers.But the seriousness of those risks was obscured,because inflation fuelled expectations that property prices would continue to rise.This heavily regulated environment provided overwhelming government incentives for banks to make bad loans.But disastrous though government action was in precipitating the globalfinancial crisis,banks were also culpable.They were complicit insofar as they succumbed to the government incentives:strong though the incentives to unethical conduct were,some banks successfully resisted.13Insofar as banks and otherfinancial institutions solicited or supported those regulatory constraints,they were guilty of even greater wrongdoing. Government regulation always involves coercion;as such,it automatically violates one of the defining components of Ordinary Decency.‘Predatory do-gooding’is unethical even when prompted by ostensibly generous motives.It is wrong to take advantage of the less articulate, intelligent,or sophisticated to impose costs on them or others through paternalistic regulation. All government regulation14has a heavy price:independent of anyfinancial costs,coercive regulation limits individual liberty.Were any of the other elements of Ordinary Decency violated?It would certainly have been unethical to generate loans by lying,or by cheating prospective borrowers.Most mortgage originators did not stand in afiduciary relationship to their customers.But it would still have been unethical to misrepresent the costs or risks of taking on a mortgage,and wrong to pressure prospective borrowers to take out loans that they could not reasonably be expected to afford and repay.15Predatory lending,and abusive practices by lenders,are indeed unethical.But so is predatory borrowing:taking out a loan that one is not willing,able or intending to repay is a form of stealing.Similarly unethical is obtaining a loan on false pretences.But‘liar loans’were endemic.The requirement for honesty works both ways,as does caveat emptor.These moral criteria apply both to individual borrowers,and tofinancial institutions themselves.Financial institutions had no excuse for not understanding and properly evaluating the securitised obligations that they bought and sold.Although the chief ethical error of mostfinancial institutions was being insufficiently directed at long-term owner value16,many also violated Distributive Justice.Distributive Justice requires that compensation reflect contributions to the organisational goal.In a business,。
Evaluating the invasiveness of Acacia paradoxa in South AfricaR.D.Zenni,J.R.U.Wilson ⁎,J.J.Le Roux,D.M.RichardsonCentre for Invasion Biology,Department of Botany and Zoology,Stellenbosch University,Matieland 7602,South AfricaReceived 10December 2008;received in revised form 31March 2009;accepted 1April 2009AbstractWe present the first detailed survey of a population of Acacia paradoxa DC.(syn.Acacia armata R.Br.),Kangaroo Thorn,in South Africa.The species is listed under the Conservation of Agricultural Resources Act as a category 1invasive plant and,until 2008,was being managed as part of Working for Water's general alien clearing operations.Acacia paradoxa is currently restricted to a small population (~11,350plants over ~295ha)on the northern slopes of Devil's Peak,Table Mountain National Park in the Western Cape.Its distribution is highly clumped,and at a local scale it has formed thick stands of up to 20plants m −ing a bioclimatic model we predict that it has a large potential distribution in South Africa,especially along the southern coast.We confirmed the categorisation of A.paradoxa as a potential landscape transformer that requires immediate control by conducting a formal risk assessment using the Australian Weed Risk Assessment system.However,the population appears to be spreading slowly,and,while there is a significant seed-bank in some places (~1000seeds m −2),this is largely restricted to below the canopy of existing plants.Therefore,the population has not and likely will not rapidly spread in area,and so containment is feasible.Dedicated and thorough annual follow ups are required because plants can produce seeds when they are 1year old and standard clearing operations have missed flowering plants.©2009SAAB.Published by Elsevier B.V .All rights reserved.Keywords:Biological invasions;Early detection;Emerging invader;Invasive alien plants1.IntroductionAustralian Acacia species were introduced to South Africa during the 19th and 20th centuries for a variety of reasons (Shaughnessy,1980;Henderson,2006).Many of these species have become highly invasive,to the extent that some are among the most widespread invasive plant species in South Africa (Wilson et al.,2007).However,there are several Australian acacias that have been introduced to South Africa that have either not established or have only formed small populations (Shaughnessy,1980).The costs of controlling invasive species scales exponen-tially with the size of area infested (Rejmánek and Pitcairn,2002).Therefore,when a potentially invasive population is identified,it should be assessed as quickly as possible to determine whether control is required or eradication is desirable (McNeely et al.,2001;Wittenberg and Cock,2001;Simberloff,2009).In particular,the biology of the species,the suitability ofthe new environment,and the population dynamics of naturalised populations should be used to evaluate the invasive-ness of the species (Mgidi et al.,2007)and to inform management.Weed risk assessment protocols (e.g.Pheloung et al.,1999)are useful tools in this regard,as they help to organise and summarise available data (Gordon et al.,2008).In this paper we provide the first detailed assessment of the population of Acacia paradoxa growing in Table Mountain National Park (Fig.1a).The species is currently classified as an emerging invader in South Africa (Nel et al.,2004)and is a category 1invader according to the Conservation of Agricul-tural Resources Act (CARA).The aims of this study are to 1)map the current population on Table Mountain,and 2)evaluate the potential of A.paradoxa to become a major invader in South Africa.2.Species descriptionAcacia paradoxa DC.is a leguminous thorny shrub that grows up to 4m tall,and produces dense clusters of yellowAvailable online at South African Journal of Botany 75(2009)485–496/locate/sajb⁎Corresponding author.Tel.:+27218083110;fax:+27218082995.E-mail address:john.wilson2@ (J.R.U.Wilson).0254-6299/$-see front matter ©2009SAAB.Published by Elsevier B.V .All rights reserved.doi:10.1016/j.sajb.2009.04.001flowers (Fig.1b)during spring (September to November in South Africa).It is native to grassy woodlands and open forests in temperate and sub-tropical regions in Australia (Maslin,2001;Franco and Morgan,2007)with annual rainfall ranging from 252to 1460mm.Its seeds have small elaiosomes (Fig.1e)and are formed from November to January in South Africa.In Australia seeds are dispersed by ants,as is the case for many other Australian Acacia species (Berg,1975;O'Dowd and Gill,1986).There is some debate surrounding its natural distribution,but it is thought to have occurred only in south-eastern Australia prior to European settlement,being introduced to Tasmania and south-western Australia more recently (Franco and Morgan,2007).The species was commonly planted as a hedge in Australia,but has now been proclaimed a noxious plant in parts of Victoria (Maslin,2001).It has also been introduced to several countries around the world.In Israel,there is a small naturalised population of A.paradoxa close to Jerusalem that probably started as an escape from a tree nursery abandoned in the 1960s,but it is not yet considered invasive (Dufour-Dror and Danin,2004).In Chile,the species was introduced as an ornamental plant (Macaya,1999),with no records on whether it has naturalised there.In California,U.S.A., A.paradoxa is a declared noxious weed (Calflora,2008).It is also naturalized in New Zealand (Webb et al.,1988).The earliest record of A.paradoxa we found for South Africa is from a herbarium specimen lodged in the University of Cape Town's Bolus Herbarium dated October 1937.All other herbarium specimens at the Pretoria National Herbarium were collected more recently,and all are from the same part of Table Mountain.This remains the only population recorded in South Africa,despite the fact that it has a distinct morphology and has been included in the main field guide of alien invasive plants for over 8years (Henderson,2001).However,systematic manage-ment of the population does not appear to have occurred until after 1998,when it was included as part of standard manage-ment operations in the area.3.Materials and methods 3.1.DNA barcodingTo confirm the morphological identification of A.paradoxa we used a DNA barcoding approach (Lahaye et al.,2008).Leaf material was frozen in liquid nitrogen and ground by hand prior to DNA extraction.Whole genomic DNA was extracted using a modified cetyltrimethyl ammonium bromide (CTAB)method as described by Doyle and Doyle (1990).The spacer and intron regions of the plastid trnL-F region were amplified usingtheFig.1.Acacia paradoxa in Table Mountain National Park:(a)A view from above the study site looking down towards Cape Town (the King's Blockhouse and the game park are on the right);(b)flowers and flower buds in September,2008;(c)old seed pods;(d)1-month-old seedling;e)fresh seeds with elaiosomes;f)standard management operation,where plants are cut using a saw or brush cutter and herbicide is applied to the cut stems.486R.D.Zenni et al./South African Journal of Botany 75(2009)485–496universal primers“c”and“f”(Taberlet et al.,1991).PCR consisted of a thermocycle of an initial denaturation of95°C for5min; 35cycles at94°C for30s,58°C for60s,elongation at72°C for 90s;and final extension at72°C for10min.Amplified,double-stranded DNA fragments were purified using the QIAquick PCR Purification Kit(Qiagen,USA)and sequenced in both directions using the ABI PRISM BigDye Terminator Cycle Sequencing Ready Reaction kit(PE Applied Biosystems)and an automated sequencer(ABI PRISM377XL DNA sequencer,PE Applied Biosystems).Sequence data were visualized and edited manually using the Bioedit software version7.0.8(Hall,1999).Using sequence data obtained from GenBank as a reference guide we identified the intergenic spacer between the trnL and trnF.This region is best suited for lower level taxonomic discrimination (Taberlet et al.,1991).To identify similar sequences in GenBank, we used our DNA sequence data in a nucleotide–nucleotide blast search(blastn;Altschul et al.,1997).3.2.Population monitoringThe study site is situated on the slopes of Devil's Peak in the northern section of the Table Mountain National Park(33.95°S, 18.45°E;Fig.2a).We started the survey close to the King's Blockhouse where some of the densest stands occur.We sampled all plants in an area of~4.5ha between May and August2008, and measured each plant's height,basal circumference,and took two measurements of canopy diameter(at right-angles);checked each plant for the presence of flower buds,flowers,seed pods,and seeds;and identified whether plants were resprouts.Initially,we removed,bagged,and dried24plants of varying sizes for biomass measurements.We took a basal cross-section of the stems in the hope of using age-rings to determine population age structure.All measured plants were either hand-pulled or chopped off at the base followed by spraying the cut stem with herbicide(triclopyr triethylammonium salt–Lumberjack™)as per the Working for Water(WfW)standard clearing protocols.As the population was much larger than initially expected,it was not possible to measure and cut every plant across the entire area.We subsequently concentrated on mapping all plants so as to obtain a reliable estimate of the total population size and distribution.A systematic survey was conducted based on walking parallel lines(up to20m apart;see Cacho et al.(2006) for an evaluation on searching strategies)extending~50m beyond the most isolated plant found.The geographic position of each plant found was marked using a hand-held Global Positioning System(GPS Garmin®GPSmap60CSx,maximum resolution of3m),and the tracklogs from the tracking lines recorded in the GPS were used as the basis for drawing a polygon of the surveyed area in Arcview GIS v.3.2.To improve accuracy, the survey was done primarily while the plants were in flower (August to November).Finally,to check for any plants outside the surveyed area,we scanned the area with binoculars from the top of cliffs above the highest plants recorded.We used Ripley's L to describe the spatial distribution of occurrence points.Ripley's L averages the number of indivi-duals within a distance(r)of a randomly chosen individual (Perry et al.,2002).We also produced a density map with a Gaussian smoothing kernel using the function density in R(R Development Core Team,2008).All analyses were done using the surveyed area as the observation window to avoid the assumption that non-surveyed areas contain no plants(Baddeley and Turner,2005).The presence of plants was visually compared with environmental layers available from South African National Parks(soil type,vegetation cover and number of management operations in the area since1998).To estimate the size at reproduction,we regressed the logarithm of plant size against the presence of signs of reproductive maturity(flower buds,flowers,or seed-pods) using a generalised linear model with binomial errors.3.3.Seed bank and germinationTo estimate the size of the seed bank,a corer(auger)was used to sample soil under two different patches of A.paradoxa. The first patch chosen contained a couple of very large plants (up to3m tall)where old seed pods were present on the plant and in the litter.We set up a grid of18m by18m that covered the whole canopy and at least10m into the neighbouring vegetation.We took a soil core at each2m by2m intersection, giving a total of100soil cores.Each sample was of~0.0003m3 (area section of33.2cm2by~10cm deep).Samples were stored,dried,and sieved using a soil sieve,and the number of A. paradoxa seeds were counted.A second area surrounding a relatively isolated plant in open fynbos with a10m by10m grid,was assessed in the same manner.From August onwards,we noted extensive germination from the seed-bank,and recorded the number and timing of seedlings emerging under two large plants(each with a canopy area of ~10m2).Germination is easy to distinguish from resprouting or regrowth,as the first one or two phylodes of a seedling are bipinnate(Fig.1d).In general,whenever we observed a plant with bipinnate phylodes,we assumed it was less than1year old.3.4.Management operationWe evaluated the population structure at three different sites that had been cleared at different times prior to our survey (3weeks,1year,and3years).At each site we surveyed,measured, and eradicated all plants(using the method previously described).3.5.Bioclimatic modellingWe used the algorithm Maxent to estimate the realised climate niche of A.paradoxa in Australia and,by projection,the likely potential range of A.paradoxa in South Africa(Phillips et al.,2006).The bioclimatic variables used to generate the model were part of the WORLDCLIM dataset of global climate layers on a30arcsec resolution grid(Hijmans et al.,2005).The bioclimatic variables used in the analysis were the eight most uncorrelated ones according to Loiselle et al.(2008):mean annual temperature,mean diurnal range in temperature, isothermality,temperature seasonality,mean annual precipita-tion,precipitation of the driest month,precipitation seasonality, and precipitation of the warmest quarter.487R.D.Zenni et al./South African Journal of Botany75(2009)485–496Fig.2.The distribution of Acacia paradoxa on the northern slopes of Devil's Peak,Table Mountain National Park:(a)The surveyed area and major features of this part of the park.The inset in the top-left shows the location of the study site in relation to the rest of Table Mountain National Park.(b)The distribution of plants surveyed,including altitudinal contour lines and the results of an analysis of the density with contours showing the percentage of the population predicted to be in a given area.The upper altitudinal limit of 540m is shown as a thicker line.488R.D.Zenni et al./South African Journal of Botany 75(2009)485–496Distribution data in Australia were obtained from georeferenced plant voucher records within the Australian Virtual Herbarium database(.au/avh/),downloaded on31July 2008.The records include occurrences inside and outside the presumed natural range of the species(south-east and south-west Australia).This resulted in a single presence-only dataset for Australia that included all known occurrences.The model was run using a subset of100random points with a minimum distance of0.5°between records.The minimum distance was required because MAXENT is sensitive to the number of records in an area,and there were multiple herbarium records from a couple of locations in South Australia that would otherwise unduly bias the results.By setting a minimal distance of0.5°we made sure that only one presence would fall inside any climatic variables grid cell.The remaining occurrence data (1004records)were used to verify the resulting model using three metrics:area under the curve(AUC),sensitivity,and specificity using the package PresenceAbsence in R(Elith et al., 2006;McPherson and Jetz,2007;Freeman and Moisen,2008). The absence data was based on pseudo-absences(1004random points with a minimum distance of0.5°from any presence record to avoid overlapping).The resulting model was then projected onto the current South African climate.3.6.Risk assessmentTo assess the potential invasiveness of A.paradoxa in South Africa we applied the Australian weed risk assessment protocol developed by Pheloung et al.(1999).Although this weed risk assessment system was developed for Australia and New Zealand,it performs well across a wide range of geographies (Gordon et al.,2008).We used the data and observations collected in this study as well as information available in the literature.In addition,we assessed the criteria for classifying plant species under the South African Conservation of Agricultural Resources Act(Act No43of1983,with amendments on regulations15and 16),concerning problem plants.4.Results4.1.DNA barcodingThe complete trnL–trnF intergenic spacer region identified for invasive populations of A.paradoxa comprised416bp.The Blast algorithm located a417bp trnL–trnF intergenic spacer sequence(accession number:AF195678)that was99%similar to our haplotype(accession number:FJ515909).The only discrepancies between these two haplotypes were two single nucleotide indels at positions367and410.The highest match corresponded to the trnL–trnF intergenic spacer sequence of A. paradoxa previously described by Murphy et al.(2000).4.2.Population status and dynamicsWe found11,348A.paradoxa plants in an area of ca.295ha (Fig.2b).The population extended from the small cliffs just above the King's Blockhouse,540m above sea level,down to the border of the Table Mountain National Park.The most isolated plant found was150m from its nearest neighbour and the average distance between plants was1m(median=0.4m), indicating that plants are highly aggregated.The most isolated patch of plants was located450m from its nearest neighbour.In fact,the majority of plants(ca.70%)were within a5ha area. Ripley's L-function produced a uni-modal distribution,due to the extremely high density in the core of the population relative to other areas.The density map(Fig.2b)highlights several additional points.The upper altitudinal limit is much more sharply defined than expected;plants appear to be distributed down a couple of the valleys;and there appear to be several clusters of plants,but these clusters have low densities relative to the bulk of the population(and are thus not apparent when using Ripley's L).The plants are found in mesic and wet mesotrophic proteoid fynbos,renosterveld grassland,forest,and thicket.There appeared to be no clear link between presence of plants and soil or vegetation type or with management regimes.Plants were found in all conditions present in the surveyed area,and the limit of the population's spatial range did not appear to match a change in edaphic or other factors.In the study area,A.paradoxa plants were up to3.5m tall and their canopies covered areas of up to31.6m2.The size distribution of the plants sampled is shown in Fig.3a.Only26 plants(about2%)were found to be resprouts.No growth rings were found when cross sections of stems were sanded and studied under a microscope.The above-ground biomass was found to be best predicted by the basal circumference rather than plant height,canopy volume(estimated as a cone),or canopy area(r2of0.58vs.0.08,0.44,and0.47respectively).Flowering started towards the end of July and continued until mid November.The production of seed pods started towards the end of November.Seedlings were first observed in August,with germination tailing off towards the end of November.Since most survey work was done prior to seed set,we assumed that the presence of flowers or flower-buds was indicative of reproduc-tive maturity.The minimum size of plants at reproduction was therefore0.3m,with the majority of plants over1.5m producing buds(Fig.3b).4.3.Seed banks and germinationWe found a total of95seeds underneath the canopy of the plants measured for seed banks,with only one seed found outside the canopy(in this case b2m from the canopy).This suggests a seed bank of approximately1000seeds m−2under large plants(3m tall),but b10seeds m−2outside the canopy.In the isolated plant(2.5m tall),only one seed was present in the sample cores,under the canopy,despite the presence of several seed pods.Within16weeks of observing seedlings germinating under two large plants that were cut down we found82and 58seedlings respectively.More than92%of these seedlings had emerged within8weeks after the plants were removed. However,the removal of the trees did coincide with our first observations of germination at undisturbed sites,so we489R.D.Zenni et al./South African Journal of Botany75(2009)485–496could not ascribe the germination to the removal of the trees per se .4.4.Management operationThe standard management operation for clearing alien plants is usually carried out by a team of ten people,with the instruction to systematically cover the target area and cut down or hand pull all invasive alien plants located (Fig.1f).The cutstumps are treated with an appropriate herbicide containing blue dye.At the Devil's Peak site,the WfW clearing team is targeting around 15different species,including Acacia ,Eu-calyptus and Pinus species.Within 3to 4days after treatment,the leaves of plants were found to have shrivelled and browned.It was therefore easy to spot individuals that had been missed by the control team after clearing.On the area evaluated 3weeks after the management operation,~2.5ha,the WfW clearing team took 3h to cover the area in July,2008.On our return survey we found 153plants left uncut.Just over half of the missed plants were shorter than 0.5m (51%),but plants taller than 1.5m (1%of the total)were also missed including some that were flowering (Fig.4a).InFig.3.Details of the population at the site:(a)Size distribution of the surveyed population (seedlings and mature plants);(b)The relationship between plant height and reproductive maturity.The presence of flower buds,flowers,or seed-pods was used as a surrogate for reproductive maturity.The line shown is from a fitted generalised linear model with binomial errors and log (plant height)as an explanatory variable;(c)The distribution of seeds in the seed-bank on a 2-m grid.Numbers indicate the number of seeds found in a 33cm 3soil sample.The slashed lines indicate the canopy of A.paradoxa.Fig.4.Size structure of Acacia paradoxa individuals greater than 1year old at three sites:(a)3weeks after the last clearing (surveyed in September 2008);(b)1year after the last clearing (surveyed in November 2008);(c)3years after the last clearing (surveyed between May and August 2008).Individuals younger than 1year (as shown by the presence of cotelydons)are not drawn because this simply reflects the survey date.That there was no sign of reproduction in the area surveyed 1year after clearing is probably due to the timing of the survey (after flowering,but before seed-set).490R.D.Zenni et al./South African Journal of Botany 75(2009)485–496total,29reproductively mature plants were left uncut.The return survey included cutting and measuring and took two people7h to complete(i.e.14field h).It should be noted that the second survey focussed exclusively on A.paradoxa and followed the systematic survey described in the methods.In the area evaluated1year after the management operation (November2008),we found770plants in5.1ha.None of the plants were flowering,setting flower buds,or had seed pods (Fig.4b),probably due to the timing of the survey(between flowering and seed-set).Four hundred and seventy two of the plants found had cotyledonal leaves and were relatively small (1–69cm).The rest(298plants)ranged from1cm(resprout)to 3.05m tall(Fig.4b).The return survey included cutting and measuring and took36field h to complete.In the area evaluated3years after the management operation (August and September2008),we found1181plants in4.5ha. Five hundred and twenty-three plants were setting flower buds or flowers(Fig.4c).We found densities of up to20plants m−2, and the biggest plant of the entire population(3.6m tall with a canopy area of31.6m2).This area was actually the first area surveyed,and as such we do not have a reliable estimate of how long it would take to complete given the standardised protocol we eventually settled upon.4.5.Bioclimatic modellingThe bioclimatic model produced a very high accuracy of prediction when projected onto the original distribution data in Australia:AUC=0.976;sensitivity=0.965(sd±0.007);speci-ficity=0.908(sd±0.01).93.7%of test data were correctly classified(Fig.5a).The logistic threshold that maximizes the sensitivity and the specificity values is0.2425.When applying this threshold to South Africa,the existing population of A. paradoxa on Table Mountain is found in an area of average predictability(0.2465and0.30),and around13%of the area of South Africa has climatic conditions that are suitable for the growth(and perhaps invasion)of A.paradoxa,mainly along the south coast(Fig.5b).The bioclimatic variables that contributed most to the results were annual mean temperature(70.6%),and annual precipita-tion(26.1%).All other variables contributed less then1%.4.6.Risk assessmentUsing all information found in the literature and the data generated in our study,we could answer39out of the49weed risk assessment questions,with enough questions answered in each section to complete the analysis(Table1).The overall score obtained for A.paradoxa was18,comprising11points for biogeography reasons,5points for undesirable attributes, and2points for biology/ecology.As the suggested threshold to consider a species as potentially invasive is6(Pheloung et al., 1999),A.paradoxa would fail a pre-border evaluation.In CARA,A.paradoxa is listed as a Category1invader be-cause its is alien to the country,is already present in South Africa,is invasive in South Africa,is a problem or a potential problem,is not a commercial plantation or subsistence species,is not of orna-mental or any other value,and its control is feasible.The recom-mendation in this case is that it should be immediately contained, indeed it is the species used as an example of this category.5.Discussion5.1.The history of Acacia paradoxa in South AfricaFrom the herbarium records,it is clear that there have been A.paradoxa plants on Table Mountain for many decades. Enquiries were made with several land managers and other interested parties in the area,but no records could be found to determine an exact date of or reason for introduction to the country or the study site.There is no mention of this species in reviews of plant introductions to South Africa,or in studies of alien woody plants in the Cape Peninsula(Shaughnessy,1986; Wells et al.,1986;Richardson et al.,1996).However,we speculate that a few individuals of A.paradoxa were introduced close to the King's Blockhouse possibly for hedging or as part of the resident forester's personal interest.The upper altitudinal limit,and largest density of plants recorded are both in the immediate vicinity of the King's Blockhouse(Fig.2b). Moreover,A.paradoxa is commonly used as hedge species in Australia(it is sometimes called hedge wattle),and,while it is available in the nursery trade in Australia,we have no evidence that it was ever traded within South Africa.We also suspect that the introduction may have been part of efforts to afforest parts of Table Mountain that were initiated in1893to restore the slopes of Devil's Peak that were suffering erosion(Britton,2006).Given that large parts of South Africa are climatically suitable for A.paradoxa(Fig.5),we would also suggest that if plants had been moved around South Africa by humans,either as an ornamental or for hedging,then the species would have naturalised in many more locations(i.e.the isolation of Table Mountain from other areas is the main factor limiting its regional spread).According to the Park's administration(SANParks)clearing of A.paradoxa started in1998,when it was first identified as a problem species.While some of the areas invaded by A. paradoxa have been visited up to five times,others were visited only once(SANParks'Geographic Information System).Some of the areas that were managed more often were also the areas with the highest densities of plants,and according to some of the park rangers these coincide with the areas where the biggest A.paradoxa plants were found in1998.Therefore,we suspect the current population is the result of a few plants initially introduced as a curiosity,followed by a long history of neglect,then subject,in the past decade,to alien plant clearing operations.While the intention of recent management efforts was to eradicate the population,precise details of what was removed are not available.However,the clearing until now can be categorised as sporadic and partial,focussing mostly on the largest and presumably oldest plants.5.2.DispersalThe presence of an elaisome on the seeds(Fig.1e)suggests that A.paradoxa is adapted for dispersal by ants.Native ant491R.D.Zenni et al./South African Journal of Botany75(2009)485–496。
