MGTS7523: Modelling Assessment program Solution

Part 1: Macquarie Island

Problem Identification

Explain what problem the Australian Government aimed to fix

Was the Problem Fixed?

Explain and justify whether the problem was fixed or not

Impact on Birds

Describe what happened to the birds on Macquarie Island as a consequence of the intervention

Key Variables & Reference Modes

List key variables + hand-drawn reference mode for each (before and after intervention)
Assumptions:

• Rats/mice = “rodents”

• Rodents eat bird eggs only

• Rabbits eat habitat only

• Ignore delays
  [8 marks]

Causal Loop Diagram 

CLD with polarities, red (+), black (–), feedback loops labelled
Paste CLD and explanation of how it represents the Macquarie Island system

Why Cats Provided Bird Protection

Explain using CLD why cats protect seabirds even while preying on them

Ecological Module

Aging Chain Model Setup

• New Stella Architect file

• Apply model settings shown in Figure 1

• Build structure shown in Figure 2

Initial Conditions

• Normal juvenile population = 1,750,000

• Normal adult population = 900,000

• Initial JUVENILES = Normal juvenile population

• Initial ADULTS = 0.5 × Normal adult population

Required Converters

• Juvenile maturation time = 180 days

• Net juvenile birth rate = 0.015/day

• Normal death rate (Juve) = 0.00223/day

• Normal death rate (Adult) = 0.0105/day

• Lobster catch = 0 individuals/day

Flow Logic

• Births = ADULTS × Net juvenile birth rate

• Deaths Juve = JUVENILES × Normal death rate Juve

• Deaths Adult = ADULTS × Normal death rate Adult

• Juve → Adult requires unit-consistent formulation

Insert Name & Registration

Add textbox beneath model.

Paste Model Screenshot

Long-Term Simulation

Plot JUVENILES and ADULTS on same chart.
Paste plot.

Behaviour Description

Describe observed behaviour and explain why.

Carrying Capacity Integration

Modify Adult Structure

Apply Figure 3 structure.

Additional Converters

• Habitat CC = 1,200,000

• Habitat effect Adult = graphical function (Figure 4)

Adjusted Death Rate Equation

Provide equation with units.

Livelihood Module

Add Converters

• ADULTS (ghosted)

• Normal Adult Population (ghosted)

• Normal CPUE = 8

• Number of boats = 25

• Normal fishing effort = 10

Graphical Functions 

Parameterise both using Stella presets.

Link to Ecological Module

• Total fishing effort × Adjusted CPUE → Lobster Catch

• Update equation.

Run Model + Plot ADULTS & Habitat CC

Paste chart + comparison with previous chart.
[5 marks]

Supply Chain Module

Create Stocks (Figure 7)

• LANDED

• STORED

• QUARANTINE
  (All start at 0)

Converters

• Transport time = 3

• Export time = 10

• Quarantine time = 7

Write Equations

• Exported

  To market
  Include units.

Death Converters

• Landed lifespan = 7

• Storage lifespan = 100

• Quarantine lifespan = 14

Connect Ecological Outflow

• Lobster catch → Landed catch

Economics Module

Price Dynamics Setup

• PRICE (stock)

• Normal price = $88

• supply:demand converter

  • supply = to market

  • demand = Normal demand (=500/day)

Run Full Model & Plot

1. PRICE

2. supply:demand

3. Normal demand

Add Price-Responsive Demand

Graphical Function: Effect of price on demand

Requirements:

• Price ↑ → Demand ↓

• Price = Normal → Demand = Normal

• Price = 0 → Demand = 2 × Normal

• Price = 2×Normal → Demand = 0

• High sensitivity at extremes

Price Influence on Supply (Final Task)

Show Entire Model + Explanation

Explain:

• How PRICE feeds back to fishing effort/supply

• Graphical function shape & rationale CLD Task

Draw CLD Using Only Given Variables

Variables:
PRICE, ADULT, JUVENILE, Expected demand, LANDED, STORED, QUARANTINE, Adjusted CPUE, Total fishing effort, Habitat CC, Lobster pop:CC, Lobster catch

Brief summary of assessment requirements

Part 1 Macquarie Island (system dynamics reasoning & CLD)

• Identify the policy problem the Australian Government attempted to solve and justify whether it was fixed.

• Describe ecological consequences for seabirds.

• List key variables and provide hand-drawn reference modes (before/after intervention).

• Create a causal loop diagram (CLD) for the system immediately before cat removal, annotate polarities and feedback loops (red = positive, black = negative), and explain why cats provided net protection despite predation.

Part 2 System Dynamics Model (Lobster Game: build SFM in Stella Architect)

• Build an ecological module (juvenile/adult aging chain), set initial conditions and rates, run long and short simulations and interpret behaviour.

• Integrate carrying capacity and show adjusted death-rate equation and resulting dynamics.

• Add a livelihoods/fishing module (CPUE, fishing effort), connect to Lobster Catch.

• Add a supply-chain module (Landed → Stored → Quarantine), include transport/export delays and deaths.

• Add an economics module (PRICE stock, expected price, price gap, price change with delay), then make demand price-responsive and link price back to supply.

• Produce all screenshots, plots (JUVENILES/ADULTS, ADULTS+Habitat CC, supply chain stocks, PRICE and related plots), equations used, and final CLD of specified variables.

Part 3 Policy application using an existing SD model (Tourism Town)

• Analyse behaviour-over-time patterns, identify dominant feedback loops and tipping point, run baseline (Fish import switch cap = 1) and propose a management strategy to prevent tourist collapse.

• Evaluate strategy against four indicators: Tourist population, Actual tourism amenity, Unemployment rate, Tourism spending per capita.

Submission requirements

• Provide Stella Architect model files, screenshots, plotted charts, equations with units, hand-drawn reference modes (photos), CLDs, and a short written justification/explanation for each deliverable.

Get Access to High-Quality Academic Solutions

Looking for clarity or guidance before starting your own assignment? Our expertly crafted sample solution is available for you to download and review. It’s designed to help you understand structure, formatting, and academic expectations so you can confidently develop your own work.

Important: The sample file is strictly for learning and reference purposes only. Submitting it as your own may lead to plagiarism concerns and academic penalties. Use it as a guide not a submission.

If you prefer a completely original answer tailored to your topic, our professional academic writers can prepare a fresh, plagiarism-free assignment aligned with your university guidelines. Every custom solution is written from scratch, checked through premium plagiarism tools, and delivered on time.

Why Order a Fresh, Custom-Written Solution?

• 100 percent original and plagiarism-free content

• Written by expert academic professionals

• Aligned with marking rubrics and course requirements

• Properly referenced and formatted

• Fast delivery with guaranteed accuracy

• Complete confidentiality

Take the Next Step

Download Sample Solution    Order Fresh Assignment