Author’s note: Time is running out for Ecuador to save its Amazon rainforests — areas which have 10,000 times the biodiversity of the Galapagos islands. Ethno-ecologist Adam Gebb looks at the problems and possibilities in a seven-part series. This article explores how fragmentation is threatening the Amazon.
By Adam Gebb
Over the past 50 years, humans have developed the planet in complete ignorance of nature’s needs for landscape connectivity — and that is an enormous problem for the Andes and Amazon ecosystems in Ecuador.
Loss of landscape connectivity is causing an enormous wave of wildlife extinctions. This loss needs immediate attention.
Landscape connectivity is a relatively new science that considers how the shape, size and placement of our remaining wild landscapes can maintain ecological processes. Ecological communities even far away from each other can be inextricably linked by species roaming to meet their year-round and long-term food and reproductive needs.
A tragic example of where landscape connectivity has been lost is between the Andes Mountains and the Amazon Basin. These enormous biomes have been treated by many of the world’s top experts as separate entities but they actually belong to the same ecological system.
The more complicated the geographical mosaic the better, especially when it causes mild variations in temperature, humidity and light. These variations support much wider biodiversity as long as temperatures remain over 40 degrees Fahrenheit. This is the case where the Andes and the Amazon meet.
By completely ignoring the connectivity needs of wildlife communities, rather than connected landscapes we now have islands of habitat no longer capable of facilitating most of the species in an area. This has caused a domino effect where the remaining species also go into decline because they were in important relationships with species that are now gone. Insect pollinators are a prime example. When they go into decline, fruit trees will bear little or no fruit which in turn causes declines in mammal populations.
Limits to connectivity generally fall into two categories: human and geographic. Building roads has caused enormous losses in connectivity for most of the planet. Roads are followed by fields, houses and growing towns. The forests that remain may look healthy but are actually experiencing steep declines in biodiversity due to edge effects. Forests near fields or clearings are brighter, dryer and windier in ways that many sensitive species cannot survive. This creates a wave of extinction that goes deep into seemingly intact forests.
There are also the human edge effects of noises, odors and hunting, to name just a few, that negatively affect mammals. When a connectivity analysis is done for an area, the viable wildlife habitat will be smaller than areas that appear to be forested or in natural condition.
Lowlands have been developed in too many areas, leaving the highlands alone to maintain biodiversity. This is one of the main causes of biodiversity crashes around the world. To maintain evolutionary processes, humans will have to return parts of many valleys to nature which in some areas will be difficult. Conserving lowlands with gentle geographies is urgent.
Geographic limits to landscape connectivity include cliffs, large mountains and water bodies which are generally ancient and unchangeable.
Ecuador’s largest conservation project is the Sangay-Podocarpus Biocorridor. It aims to connect the two national parks in its name via a 150-mile corridor of conserved areas along the Andes Mountains. The boundaries of the biocorridor include very few lowland areas that were until recently the more important forested parts of the local ecosystem. While this is a great conservation project, it will do very little to maintain Ecuador’s evolutionary processes and therefore will not make a large positive impact when it comes to maintaining the region’s legendary biodiversity. Few species just need to get from one mountain to another. It’s the connection to lowlands that’s vital. And the biodiversity of the Andes is a tiny fraction of what exists in the Amazon.
Biodiversity hot spots in the Ecuadorian Amazon actually have less to do with the wildlife there now than with ancient evolutionary processes that occurred as climate change forced millions of species to adapt as they moved. The real cure is to reconnect the Andes Mountains and the Amazon Basin. This would allow the highest biodiversity forests on the planet that are currently in the Amazon to migrate into cooler climates at the base of the Andes as they have done repeatedly for 100 million years. The next 1,000 years are predicted to be hot. For many species, they either migrate into cooler areas or they become extinct.
For the last few centuries, human infrastructure has been built while ignoring the connectivity needs of surrounding wildlife communities. Around the world, there is no choice but to reforest and re-wild key connectivity areas in order to avoid drastic biodiversity losses. In Ecuador, many of the areas needing reforestation are pastures at the base of the Andes where reconnecting these magnificent mountains to the Amazon is possibly the world’s most important biodiversity challenge.
Having carefully designed connected landscapes in Ecuador would allow what is possibly the most biodiverse forest on the planet to maintain the evolutionary processes that create new biodiversity. This will be the topic of the next article in this series.
Adam Gebb is Executive Director of the Andes Amazon Conservancy.