Why should I care about plants? And what is he really doing…

Many people have asked me in the past why I bother to study plants and what it is I am actually really doing. As most people know it is never straight forward to explain a very specialized subject or skill to someone who has most likely never been exposed to it. Yes, most people have studied biology at school, maybe even done some plant science (e.g. studying the process of photosynthesis), but it probably sounds very alienated to someone when I tell them that I climb trees, collect plants, measure leaves and study their habitats (where they grow and why they grow there). I guess if I put it like that, it actually sounds like a job no one really needs or at least no one wants to pay for. It is at this point where many, so called Plant Scientists, would give you a whole bunch of justifications why their job is so important. However, their arguments probably don’t mean much to you or you don’t necessarily think any of their work is affecting you directly. Well, let me try to explain to you what Plant Scientist (and therefore myself) actually do and why we all should care about it.

Plants very simplistically allow us to breathe, they provide food to us, are used to produce most of the products you use in your daily life (e.g. clothes, cleaning products, housing material, fuel etc.), regulate the climate, clean the air, prevent flooding, are used to produce many of our medicines. Scientists often term these different amenities ‘ecosystem services’. These ‘services’ also include less obvious aspects such as just simply enjoying plants (and nature); a service that is often less appreciated by people. Fair enough you would think, but what is he really doing and how is this helping me? For example, how is him climbing trees and collecting plants in Honduras relevant to any of this?

Most of the world’s plant diversity (I refer here to the number of different species) occurs in tropical and sub-tropical regions; in comparison Ireland has relatively poor plant diversity. For example, Ireland and the UK combined have only approximately 3,800 different species of plants (this includes many plants that would naturally not occur in Ireland or the UK, but got introduced by people). Honduras on the other hand has over 9,000 different species but is only about half the size of the UK and Ireland (approximately 120,000 km2). There are several explanations for this, which I won’t go into here, but what I want you to take away from this is that Honduras is floristically much richer. Any cynical person would now think why is it relevant how many species of plants there are in a country? Well, the number of plants is usually a very good indicator on the services that they can provide, which makes a more species rich ecosystem more complex (ecologically not necessarily structurally!).

One of the biggest challenges is that currently only a very small proportion of plants are being utilized effectively and/or are well studied for their usefulness (e.g. as food, medicine etc.). In many developing countries such as Honduras, plants are still much more valued and used in more diverse ways compared to in developed countries such as Ireland. People often share a stronger opportunistic relationship with plants as their livelihood is much more directly interdependent on plants. Anyways, let’s get back to the point on why I go to Honduras and climb trees…

This rich plant diversity is vastly understudied and for many Central American countries we still don’t even know how many plants they really have. Although we have some indication for many countries, their species numbers are often not very comprehensive and/or out of date. How can we study the use of plants if we still don’t fully know how many plants there really are. For example, in 2013 I visited Honduras as part of my PhD research and discovered a tree that was not known to exist in Honduras. The 35m tall tree is a close relative to very important economical trees such as plums, cherries, apricots etc. It is amazing to think that such a tall tree can still be discovered even in this day of age, but it also highlights how little we still know about such less well studied regions. There are most certainly many more, yet to be discovered species that have the potential to be of global significance.

One particular life-form of plants that have received even less attention compared to trees and ground vegetation are so called ‘mechanically dependent’ plants. This life-form includes anything that grows on top of other plants. Most people are actually quite familiar with this group, as it includes most orchids and many popular house plants (e.g. aroids). As the name suggests they can mostly only grow on top of other plants. However, they are typically not parasitic (except for mistletoe). Due to their growth habit (i.e. growing above ground level), it is often very difficult to study these plants. That’s where I come in! As a qualified rope access technician, I have the necessary climbing skills and equipment to accent into the upper forest strata where many of these plants grow. In the past I have tried to answer questions such as: How many of these plants there are on an individual branch, tree, or in a region? Are these plants more diverse and frequent than other plants? Why do they grow there? And how are they adopted to survive in such challenging growing conditions?

It will surprise you to hear that over 10% of all global plants are ‘mechanically dependent’ (this estimate excludes mosses and other lower plants) and that in tropical forest such as in Honduras, they can even account for over 20% of all plant species. So they are really important! Because they grow ‘mostly’ on trees, they very much depend on healthy, old growth forests. One major problem is that many of these forests are being cut down across the globe. In Ireland for example, only about 4% of natural forests still remain. Although the percentage of ‘natural’ forest is still much higher in developing countries, current deforestation rates are worrying and unsustainable. The problem is obvious; cutting down forests that are in many cases still completely understudied, creates a number of issues. Firstly, the hydrological cycle will be affected because less water is being recycled back to the atmosphere through the plants (that’s where your school biology comes in, as plants lose water in the process of photosynthesis). Secondly, many unknown and potentially useful (in terms of medicinal and economic value) plants will disappear. Lastly, it will have long term negative implications to local communities (e.g. loss of fertile soils). There are many more direct and indirect, short- and long-term impacts that result of deforestation (e.g. heat transfers, nutrient and mineral leaching, change in forest structure and climate etc.) but for simplicity, I decided not to further discuss them here.

So one of the reasons why I go to Honduras, climb trees, collect and identify plants is because it will help Plant Scientists like me, to identify regions of conservation concern (e.g. an area with high plant diversity). Conserving these areas is very crucial at different levels; for example, on a local level it can help to support local traditional farming communities, which rely on the integrity of these forests (and of course the plants that grow in them); on a regional level it will help to secure regulatory ecosystem services (e.g. water purification); and on a global level, and that’s where you come in, it will mitigate against extreme climates (e.g. droughts, flood etc.). Studying plants in tropical regions has the capacity to directly and indirectly affect people in Ireland and elsewhere in Europe. Of course this is not what every Plant Scientist does, but it is one of the many facets Plant Scientist like I have specialized in. Sadly it isn’t possible to travel around the world and do that all the time and it is for that reasons why many Plant Scientists often specialize in more than one area. For example, when I am not climbing trees, I am conducting climate change experiments back in Ireland. Here I place plants into different controlled plant growth chambers, where I am simulating different atmospheres conditions and study their responses (e.g. how much water they lose or photosynthesis).

I hope that this short post helps to explain what some Plant Scientists do and why we all should really care about plants (...here at home and elsewhere).