One of the most fruitful sub-fields in ecology is using climate variables to predict species’ geographic distributions. For the uninitiated, species distribution modelling assumes that species are limited in their distributions to suitable climate zones. By studying the environmental conditions where species are known to occur, you can infer the total geographic distribution by calculating the suitability of unsampled regions based on the environmental. Furthermore, using the same principle, species distribution modelling can forecast the effect of future climate change of the distribution of life on earth.
The trouble lies in the spatially-structured world we live in. Species distributions, especially at large spatial scales, are spatially-autocorrelated due to constrained dispersal. Similarly, climate variables are also spatially structured because the meteorological processes at proximal regions are generally more similar than those at distant sites.
When trying to link species distributions to climate conditions, the challenge lies is separating spatial and environmental correlations in species distributions. Specifically, we should identify three patterns in the geographical species distributions.
We must first identify ‘true’ correlations with the environment, which are independent of spatial patterns (E|S).
Next, we must identify the environmental-associations that also have a strong spatial structure (E∩S). This is known as exogenous spatial autocorrelation because it is due to autocorrelation is the underlying variables.
Finally, we need to identify spatial patterns that are completely independent of environmental conditions (S|E). This is called endogenous spatial autocorrelation because it supposedly stems from spatial processes, such as dispersal.
The Theory of Island Biogeography is remarkable because it suggests that patterns of species co-existence are the consequence of chance, history and random dispersal. Before its publication, community ecologists generally assumed that species co-existence was due to deterministic niche-assembly, where the number and relative abundance of species were a result of ecological niches and the functional roles of each species.
Like the theory itself, MacArthur and Wilson have also reached cult-like status. Perhaps a most telling way of illustrating this fact is not by listing the prizes awarded to these two men (and there were many), but rather by listing the academic prizes named after them! The Ecological Society of America, for instance, awards the ‘Robert H. MacArthur Award‘ to eminent mid-career ecologists and the American Society of Naturalists grants the ‘Edward O. Wilson Naturalist Award‘ to mid-career researchers who make significant contributions to a particular ecosystem of group of organisms. Similarly, the International Biogeography Society has the ‘MacArthur & Wilson Award‘ for notable contributions to the field of biogeography. Needless to say, MacArthur and Wilson are very influential and well-respected by contemporary ecologists (well, in most cases…).
The funny thing is that their paradigm shifting idea was actually proposed two decades earlier, by the less well-known lepidopterist Eugene Munroe. Continue reading →
Although ecology doesn’t have many general laws, one most likely to qualify is the species-area relationship. If you walk through a field in a straight line and count all the different species you come across, you’ll notice that the total number of species increases as you progress along your straight path. After a while, however, you’ll start seeing the same species over and over again until you eventually find that you’re no longer spotting any new ones. This is the asymptotic species-area curve. While the exact mathematical form of the relationship is still hotly debated, it is safe to assume that it is an increasing function that reaches a plateau once all the species have been encountered.
I’ve written about Golden Gate Highlands National Park in the past.
It’s a region that is very close to to my heart; I’ve spent hundreds of hours (and thousands of footsteps) on the sandstone slopes. Unfortunately, there are no complete guides to the hiking routes in the park – so I set out to make one of my own.
You can find route descriptions, hiking profiles, maps and photos of the main routes in the park by visiting this new page on my site. You can also download the route information as .kml shapefiles that can be imported into Google Earth or any other GIS platform.
Should we conserve nature at the expense of the economy? Specifically, should we risk the collapse of major industrial sectors to save species?
We’ve created modern buzzwords like “sustainable development” and “new conservation” to explain multiple-objective conservation programs because many argue that conservation is only sustainable when it aligns with other economic, social and political goals. I’ve even argued this point-of-view in the past. Society is petrified of putting an end to the exploitation of nature because we worry about the terrible consequences of dismantling the modern-day economy. Should we worry about the impending threat of unemployment, debt and unpaid mortgages if we were to choose conservation instead of consumption?
The short answer: No! Well, at least not if the past is any predictor of the future. Continue reading →
As an aspiring ecologist, I am well aware that publishing a paper in Natureor Sciencewould give my career an incredible kick-start. But, like so many others, I didn’t know how to get my name printed on the glossy pages of the two oldest and most prestigious weekly scientific journals. So I did what any good scientist would do – no, this time I didn’t check Wikipedia – I knuckled down and poured over the pages in these celebrated periodicals. I spent countless nights without sleep, trying to crack the code.
Just as I was about to give up, I saw a glimmer of hope: a golden thread linking the fortunate submissions to these two behemoths of academic excellence. I managed to reverse-engineer the path to success and I will be so generous to share my astounding findings with you. But before I do that, a word of warning: my how-to guide only applies to ecological studies. Physicists, physiologists and… um… uh… anyone else (I ran out of alliterative scientific sub-fields) will have to find their own strategies. Continue reading →
If you’re reading this, then it’s safe to assume that you love nature. Your passion for all creatures great and small might even have pushed you to pursue a career in ecology or conservation biology. But is passion enough?