Hi all! I am a totally new environmentalist and would love any and all direction in this manner. When looking at a list of scientific names for plants, what pieces of the taxonomy should I be comparing to determine which set is more diverse? Thanks for any and all help!
First, what is your question? Your hypothesis? There are many, totally different, ways to quantify biodiversity, but you have to have a research question/hypothesis to know which one you need.
Measures of diversity include number of species per genus or per family or per order. Those numbers can be somewhat misleading because the taxonomic categories like genus or family are just groups of whatever size the taxonomists want (so if one genus has 100 species and another genus has 10 species, that doesn’t really mean a whole lot. From your question, it seems like this aspect of diversity is what you’re asking about.
And there’s functional diversity (are all the species of fish in the pond detritivores or are there predators and herbivores also?
And then there’s alpha, beta, and gamma diversity.
iNaturalist has features that allow you to see a taxonomic tree of a list. If you made the lists of species in “Lists” you can go there and click “taxonomic tree view” or something, sorry, I forget the details but it shouldn’t be hard to do.
I think just looking at these taxonomic trees and seeing how dense/broad/long they appear to be is a good way to get an overall idea of “diversity”, as I think most people would understand that term.
It’s also a great idea to count how many families of plants are represented; this is maybe the best way to get a snapshot of overall diversity relatively easily in my opinion.
This is complicated because, for example, we could say a list of one fern and one family of flowering plants is more diverse than a list with three families of flowering plants, because ferns are more evolutionarily divergent. Or maybe we are only concerned with counts of distinct species. I guess most people’s idea of biodiversity encompasses both of these in some balance, many species but also divergent, “taxonomically broad” species (which is a more diverse set: a set with just one fern and one rose, or a set with six species of rose but no ferns?)
The scientific name alone (genus+species) won’t be that useful because while species in the same genus are closely related, a species can be in a different genus and still quite closely related, or not; the species/genus name won’t tell you that alone.
You mentioned that you are an environmentalist, so you might be interested in the conservation value of an area. For this purpose, whether the area is more or less diverse (however you define it) is not necessarily the most useful thing to know. Instead, it might be more useful to evaluate if it supports good populations of threatened species, or species endemic to your region. An area with fewer species, but with good populations of some rare or threatened species, is likely to make a greater contribution to conservation than an equal sized area with many species, all of which are widespread generalists, or even non-native, for example.
Very good addition…biodiversity hotspots:
Hi! Thanks for your response. My project is strictly looking at plant species. My research question is “How does the use of herbicides on the Fuller Brook Path, affect the biodiversity present on the path compared to a designated sanctuary, in the same town?” My hypothesis is that the sanctuary will be much more diverse, but I’m struggling to prove that with strictly species names. Im unsure if comparing the sets of plants in each region, by the diversity in their genus and species, is enough? Thanks!
This is so helpful, thank you! I will look at the Lists tabs and see where that takes me:)
This is such an important thing to consider. I will absolutely work this into my project – I appreciate it!
One of the challenges with measuring biodiversity is that it is a complex, multi-faceted thing that can’t be captured in a simple number, like the number of species present. For your research question, I’d suggest to check for any species that were listed when the sanctuary was established (perhaps there are sanctuary staff who could help advise?). There might be species that are indicators of good quality habitat. You could also check your lists of species for how many are non-native or even invasive - all else being equal, the more of these present, the less likely the area is to be of high value for biodiversity. You could also check with a local university or environmental agency if there are lists of threatened plants or other lists of plants of conservation interest that you could refer to. Presence of such species could be an indication of conservation value. All of that is before you consider abundance - a single specimen of a plant is quite different to a large population of the same species. The timing of herbicide use or other management measures might also be relevant (e.g., whether it leaves time for plants of conservation interest to flower and set seed first). Good luck!
It will be very challenging to collect data that is good enough to actually address that question. Comparing the two locations isn’t valid because there may be any number of reasons why they have different diversity beyond herbicides. You’d have to control for all of those (mostly unknowable) variables.
You won’t be able to use iNat observations made by other people, so you’d need to go out and document the plant diversity yourself. It sounds like you’d want to measure diversity within the sprayed areas and adjacent non-sprayed areas. And you’d want to do this at multiple locations for replication. If this is a serious project, where you want data that can actually be trusted, you’ll need to study up on experimental design so that your data is statistically sound.
Ecological research like this is profoundly difficult and requires a solid understanding of experimental design–otherwise you can get into trouble really quick (by drawing false conclusions).
I did a very quick literature search using Google Scholar and found a review paper somewhat related to your topic: Forestry herbicide influences on biodiversity and wildlife habitat in southern forests (PDF)
For the past 2 years Cape Town has had no mow verges (on motivated request). From research we now know not to mow till November
I agree with @pfau_tarleton as to the challenges. Definitely true that you won’t be able to obtain a nice clean answer from existing iNat observations or in a short timeframe.
But, don’t let this discourage you from making a start. If you are able to closely observe these areas over a period of time, you will make all kinds of personal discoveries, and get to know the plant biodiversity of the area better. And you might well find a sensitive species getting sprayed, or make some other observation that helps to improve management of the path. iNat can be a good tool to find other people who care about plants in the area and make connections with them, too.
I will reiterate what was said before: first, you would need to know how the biodiversity in those two locations compared before the herbiciding began. Then present-day diversity would indicate changes since then.
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