Question

The abundance (X) of a plant species with respect to the anthropogenic stressor habitat destruction (h) is shown. The solid and the dashed curves represent stable and unstable population equilibrium abundances, respectively. \includegraphics[width=0.5\linewidth]{45a.png}
In the absence of any stochasticity, and with increasing values of h, what is the value of h at which a sudden population collapse would occur?

• A. 2.5
• B. 2
• C. 4
• D. 3

Hint:

In population dynamics, particularly those influenced by environmental stressors, it's crucial to recognize threshold points on stability graphs. These thresholds often signal significant ecological shifts or tipping points that can dramatically affect population sustainability.

Answer 1

The Correct Option is A

Step 1: Analyze the graph dynamics.
The graph displays the relationship between habitat destruction \( h \) and plant species abundance \( X \). It illustrates stable equilibria (solid curve) and points of instability (dashed curve) for the population. The key is to determine where the transition from stability to instability occurs, indicating a potential collapse. Step 2: Identify the transition point for sudden collapse.
Upon careful examination, the critical transition from a stable to an unstable state—the threshold at which a sudden collapse is likely to happen—occurs at the value \( h = 2.5 \). This is the point where the stable population's last solid equilibrium point exists before turning into the dashed line, representing unstable conditions leading to a population collapse.