The best way to represent the given data would likely be a stacked bar graph. Here's why:
1. Categorical Data: The data is divided into categories of species, which fits well with the bar graph format.
2. Comparison of Two Related Metrics: Both "Critically endangered (%)" and "Endangered or vulnerable (%)" need to be displayed for each category. A stacked bar graph would allow you to show both metrics in a single bar per category, making it easy to visualize the total percentage and the proportion of each group within the total.
3. Relative Size and Proportion: By using a stacked bar graph, it becomes straightforward to compare the proportions of critically endangered species against those of endangered or vulnerable species across different categories.
An example stacked bar graph would have the species as the x-axis categories, and the y-axis representing the percentage. Each bar would be split into two segments: one for "Critically endangered (%)" and another for "Endangered or vulnerable (%)".
Here's a simple representation of how it might look:
```
|
| Critically Endangered Endangered or Vulnerable
| Plants |###########################|#########################
| Invertebrates| |###############
| Freshwater fish|#############|###################
| Amphibians |##########|##############
| Reptiles |#####|###########
| Birds | |######
| Mammals |##|##########
----------------------------------------------------
0% 25% 50% 75% 100%
```
This way, the graph provides a clear visual representation of how each species category is impacted in terms of being critically endangered and endangered or vulnerable.
