Jabiru Park Matrices
1. **Problem 1a:** Express staffing numbers as a matrix.
Given:
$$S=\begin{bmatrix}17 & 38 & 8 \\ 21 & 34 & 5 \end{bmatrix}$$
This matrix has 2 rows (Female, Male) and 3 columns (Full-time Rangers, Part-time Rangers, Admin staff).
2. **Problem 1b:** Find total Female and Male staff using row sums.
For Female:
$$F=17+38+8=63$$
For Male:
$$M=21+34+5=60$$
Hence the column matrix:
$$\begin{bmatrix}63 \\ 60 \end{bmatrix}$$
3. **Problem 1f i and ii:** Transition matrix for Happy/Unhappy workers.
The transition matrix T:
$$T=\begin{bmatrix}0.85 & 0.3\\0.15 & 0.7\end{bmatrix}$$
Rows: Today (Happy, Unhappy) Columns: Tomorrow (Happy, Unhappy)
4. **Problem 1f iii:** Initial state matrix (E0) with 98 Happy and 25 Unhappy workers:
$$E_0=\begin{bmatrix}98 \\ 25\end{bmatrix}$$
5. **Problem 1f iv:** Number expected next day:
$$E_1 = T \times E_0 = \begin{bmatrix}0.85 & 0.3\\0.15 & 0.7\end{bmatrix} \times \begin{bmatrix}98 \\ 25\end{bmatrix} = \begin{bmatrix}0.85\times98 + 0.3\times25 \\ 0.15\times98 + 0.7\times25\end{bmatrix} = \begin{bmatrix}91 \\ 32\end{bmatrix}$$
Rounded values: 91 Happy, 32 Unhappy
6. **Problem 1f v:** Four days later, multiply by $T^4$:
Using given values:
$$E_4 = \begin{bmatrix}83 \\ 40\end{bmatrix}$$
7. **Problem 1f vi:** Steady state vector $E_s = \begin{bmatrix}h \\ u\end{bmatrix}$ satisfies:
$$E_s = T E_s$$
So solve:
$$\begin{cases}h = 0.85h + 0.3u \\ u = 0.15h + 0.7u\end{cases}$$
With constraint $$h + u = 123$$.
Solving yields:
$$h \approx 82, \quad u \approx 41$$ (rounded)
8. **Problem 2a:** Female frogs in age groups:
One year old: 850, Two years: 940, Three years: 530, Four years: 280
Initial state matrix:
$$S_0 = \begin{bmatrix}850 \\ 940 \\ 530 \\ 280\end{bmatrix}$$
9. **Problem 2b & c:** Leslie matrix $L$ (4x4) from birth and survival rates:
$$L = \begin{bmatrix}3.6 & 2.9 & 1.7 & 0.6 \\ 0.43 & 0 & 0 & 0 \\ 0 & 0.31 & 0 & 0 \\ 0 & 0 & 0.15 & 0 \end{bmatrix}$$
10. **Problem 2d i:** Predict number of female frogs after 1 year:
$$L \times S_0 = \begin{bmatrix}3.6 & 2.9 & 1.7 & 0.6 \\ 0.43 & 0 & 0 & 0 \\ 0 & 0.31 & 0 & 0 \\ 0 & 0 & 0.15 & 0 \end{bmatrix} \times \begin{bmatrix}850 \\ 940 \\ 530 \\ 280\end{bmatrix} = \begin{bmatrix}6855 \\ 366 \\ 291 \\ 42 \end{bmatrix}$$
11. **Problem 2d ii:** Population after 3 years (given):
$$S_3 = \begin{bmatrix}406089 \\ 44408 \\ 3500 \\ 0 \end{bmatrix}$$
Total:
$$406089 + 44408 + 3500 + 0=453997$$
12. **Problem 3a:** One-step dominance matrix $T$ shows which species dominates which according to given matrix:
Species order: Gr (Grass), M (Mouse), R (Rabbit), G (Grasshopper), S (Snake), L (Lizard), H (Hawk)
$$T=\begin{bmatrix}0 & 0 & 0 & 1 & 0 & 0 & 0 \\ 0 & 0 & 0 & 1 & 0 & 0 & 0 \\ 0 & 0 & 0 & 1 & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 & 0 & 0 & 0 \\ 1 & 0 & 0 & 0 & 0 & 0 & 0 \\ 1 & 1 & 1 & 0 & 1 & 1 & 0 \end{bmatrix}$$
13. **Problem 3b:** Two-step dominance matrix $T^2$:
$$T^2=\begin{bmatrix}0 & 0 & 0 & 0 & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 & 0 & 0 & 0 \\ 0 & 0 & 0 & 1 & 0 & 0 & 0 \\ 0 & 0 & 1 & 0 & 0 & 0 & 0 \\ 1 & 1 & 0 & 3 & 0 & 0 & 0 \end{bmatrix}$$
14. **Problem 3 Rank Order:** Summing $T + T^2$ results in dominance totals:
- Hawk (H) dominates 10 species.
- Snake (S) and Lizard (L) dominate 2 species each.
- Grasshopper (G), Mouse (M), Rabbit (R) dominate 1 species each.
- Grass (Gr) dominates 0.
Final rank order from highest to lowest dominance is:
$$\text{Hawk} > \text{Snake, Lizard} > \text{Grasshopper, Mouse, Rabbit} > \text{Grass}$$