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自然是如何被调节的？

1 生态惊喜与调节思维

这里有一个令人震惊的事实：在太平洋西北部，树木需要鲑鱼。

什么？

没错，树木需要鲑鱼。想让我详细解释一下我是如何得出这个发现的吗？

好的，我来为您解释。

关于自然界，包括我们的身体，有一个普遍的真理，那就是一切都处于调节之中。当我说调节时，是指在我们的身体中存在着各种物质。

有些物质含量极少，有些含量适中，还有些含量较大。这些水平，这些含量都由身体的各个系统所调控，通过各种调节机制来维持平衡。

其中一种重要的机制就是反馈调节。这种调节非常重要，因为某种物质含量过高可能导致疾病，含量过低同样也会引发疾病。

因此，科学家们致力于破解身体中的调节规律，确定胰岛素或红细胞等物质的适当水平。这对于管理健康状况和应对各种医疗情况都具有重要意义。

2 塞伦盖蒂法则与关键物种

身体中的这些规律在更广阔的自然界中同样适用。研究表明，自然界中存在着一系列规则，这些规则主宰着动植物的相对数量。当我们深入理解这些规则时，我们就能更好地管理这些地方，实现可持续发展，确保它们的健康和我们的健康。

在社会享受着农业和医学领域巨大进步的同时，过去50到60年间，生态学家们也在不断深化对自然界运作方式的认识。

我将这些发现汇集整理，形成了一套被称为塞伦盖蒂法则的规则体系。之所以称其为塞伦盖蒂法则，是因为你能在雄伟的塞伦盖蒂平原上，清晰地观察到这些规则的运作。

当然，这些规则在伊利湖等其他地方也同样适用，只不过"伊利湖法则"这个名字可能不会让这本书卖得那么好。

在这些规则中，有一条特别重要的发现：某些动物比其他动物更为重要，它们对所在生态群落产生着远超其数量比例的影响。

关于自然界，人们常常怀着一种诗意的想象，认为每个生物都有其特定的位置和存在的意义，一切生物都同等重要。然而，这种观点并不准确。

这些生态系统的运作往往更依赖于某些特定物种或少数物种群体，而不是所有物种平等贡献。认识到这一点极其重要，因为一旦我们失去这些关键物种，整个生态群落就可能走向崩溃。如果这些群落以某种方式受到破坏，重新引入或增加这些物种的数量可能会对整个生态系统的健康状况产生重大的连锁影响。

让我们来看一个典型案例。在美国黄石国家公园，有一个广为人知的狼群重新引入的故事。早年间狼群在美国本土48州被完全灭绝。最后一只狼于1924年左右在黄石公园被猎杀。在此后的70年里，黄石公园再也没有出现过狼的踪迹。

你可能会问，这有什么关系呢？没有这些大型捕食者我们不是照样生活得很好吗？

然而，生态学研究的发现彻底颠覆了这种观念。这些大型捕食者在生态系统中扮演着至关重要的角色。

在黄石公园的案例中，令人惊讶的是，树木竟然需要狼的存在。

请仔细想想这个说法：树木需要狼。

你能想象出它们之间是如何建立联系的吗？

这种联系是通过狼群控制鹿和麋鹿的啃食行为实现的。在那段没有狼的70年里，植物和树木的生长在黄石公园一直受到抑制。直到1995年，狼群被重新引入公园。仅仅十年之后，人们就能明显观察到黄石公园景观的变化，这些变化还带来了其他物种数量的显著增加。

类似地，我们发现某些物种会对其他物种产生强烈的间接影响。

比如在太平洋西北部，我们发现树木的生长竟然依赖于鲑鱼的存在。要知道，河流中本身并不富含营养物质。这些河流中的大量营养物质实际上是通过鲑鱼的身体从海洋输送而来的。

当这些鲑鱼被各种食肉动物捕食后，它们的尸体留在河岸上逐渐分解，尸体中的营养物质就会转化为树木的天然肥料。

通过科学研究，我们甚至可以追踪这些营养物质是如何从海洋迁移到太平洋西北部树木体内的。

这种奇妙的生态联系，又有谁能事先想到呢？

3 生态修复与人类管理

随着我们不断发现生态系统中错综复杂的隐藏联系，我们开始明白为什么我们过去的某些行为会造成如此严重的破坏。

但转念一想，我们也意识到为什么现在采取一些看似微小的行动就能带来如此丰厚的回报，产生如此显著的积极影响。这些生态系统，这些精密的生命之网，往往只需要重新引入某些关键物种就能重新编织完整。

这一认识极其重要，因为无论我们是否愿意接受，我们已经成为了自然界的管理者，已经接管了这个责任。我们正在尝试从长远角度管理自然，既要确保人类能获得所需的资源，同时也期望自然能够永续存在。

因此，我们必须继续探索这些相互作用，无论是人体内的相互作用还是自然界中的相互作用，以更好地管理我们的未来。

这种探索的回报在医学领域已经非常明显：每一项发现，每一种新药，我们治疗众多疾病的方式，这些全都是过去50年间深入理解这些基本规则所结出的硕果。

我们现在需要将这种思维方式推广到自然界中，只有这样才能更好地管理我们的星球。如果我们能像管理自己的身体那样用心管理这个星球，那必将引发一场革命性的变革。

How Is Nature Regulated?

Introduction

So, here's a shocking fact. In the Pacific Northwest, the trees need salmon. What? The trees need salmon. Do you want me to unpack this a little bit as how I got to that aha? Yes, please.

Everything is Regulated

So something that's generally true about nature, including our bodies, is that everything is regulated. And what I mean by regulated, it means that in our bodies, there's all sorts of substances. Some that are in very small amounts, some that are in sort of medium amounts, some that are in large amounts. And that those levels, those amounts are kept in check by some of the body's systems. By all sorts of regulatory systems. Some of that is feedback regulation. And that's important because sometimes if we have too much of one thing, that's a disease. Too little of something, that's also a disease.

So, for scientists to figure out the rules of regulation in the body, to know what the right level of insulin is, or what the right level of red blood cells are. That's been really important to managing health and managing all sorts of situations.

The Serengeti Rules: Regulation in Nature

So, what's true for the body is also true in broader nature. It turns out there's rules in nature that govern the relative abundance of plants and animals. And when we understand those rules, we know better how to manage those places for sustainability, for their health and our health. While society's been humming along and enjoying all these advances in agriculture and medicine. In the last 50 or 60 years, ecologists have learned a lot about how nature works. I've codified these into a set of rules called the Serengeti Rules. I call them the Serengeti Rules because you can see them in operation in the magnificent Serengeti. You can see them in operation all sorts of other places like Lake Erie. But I don't think Lake Erie rules would have sold as many books.

The Importance of Keystone Species

So, a couple of those rules that are really important is that some animals are more important than others, meaning they have an outsize impact on the communities in which they live. There's sort of this poetry about nature of, you know, every creature has its place and its purpose and everything is equally important. That's not true. The functioning of these ecosystems are sometimes much more dependent upon certain individual species or small groups of species than others. That's really important knowledge because if we lose those species, those communities can collapse. And if those communities are somehow compromised, reintroduction or boosting those species can have great knock-on effects in the overall health of the ecosystem.

Case Study: Wolves in Yellowstone

So, for example, in Yellowstone National Park in the United States, it's a pretty famous story of reintroduction of wolves, which had been exterminated from the lower 48. And the last wolf was killed in Yellowstone in about 1924. So, there have been no wolves for 70 years in Yellowstone. And you might say, so what? We can get along without these large predators. Well, that's been shattered by ecological discoveries. These large predators play a really important role. And in the case of Yellowstone, essentially, trees need wolves. So think about that for a second. Trees need wolves. How do you draw, you know, how do you draw that connection in your head? Well, it's by wolves controlling the browsing and grazing of deer and elk. That was absent for 70 years. It was stunting plant and tree life in Yellowstone. And so, wolves were reintroduced in 1995. And within a decade, you could see changes in the landscape of Yellowstone. And those changes led to increased abundance of other sorts of creatures.

Hidden Connections: Salmon and Trees

Similarly, we know that some species have really strong indirect effects on others. So, for example, in the Pacific Northwest, the trees need salmon. Rivers don't have a lot of nutrients. A lot of the nutrients in those rivers comes in from the ocean in the form of salmon bodies. And when those salmon are taken by all sorts of carnivores and when those carcasses are left on the stream banks, the nutrients from those carcasses fertilize the trees. And we can actually trace those nutrients from the ocean into the trees in the Pacific Northwest. Who would have thought of such things?

Managing Nature for the Future

As we've learned about all sorts of hidden connections in ecosystems, we're realizing, first of all, why were some of our actions so damaging. But flip side of that coin is why a little bit of action now can be so rewarding, can be so positive. And that these systems, these sort of webs of life can be restitched just by the introduction of certain key creatures.

This is really important because we are nature's manager now, whether you like it or not, we've taken it over. We're trying to manage nature for the long run, so that we have the things that we need and hopefully, nature can persist. So we need to keep exploring these interactions, whether they're interactions within the body or their interactions out there in nature, to manage our future. You see the payoffs in medicine, every discovery, every new medicine, the way we manage so many diseases. That's entirely the fruit of the last 50 years of understanding these basic rules. We need that same sort of mindset to be taken outdoors into nature so that we can manage the planet better. If, if we, if we managed our bodies the way we manage the planet, there would be a revolution.