BIOS1301 Joined Components

Introduction to Invertebrates and Biodiversity

  • Invertebrates: Includes insects, molluscs, arachnids, and crustaceans; essential for ecological balance and human activity (Wang, 2024).

  • Threats to Biodiversity:

    • Global biodiversity loss due to pollution, climate change, and habitat loss (Dirzo et al., 2014).
    • In Australia, urban expansion in Sydney disrupts ecosystems, facilitating invasive species (NSW Environment and Heritage 2023).

  • Ecological Importance of Invertebrates:

    • Key for biodiversity in urban green spaces; inform conservation strategies (McDonnell et al., 2009; Beninde et al., 2015).
    • Essential for nutrient cycling and food webs in wetland ecosystems (Batzer & Wissinger, 1996).

Habitat Segmentation

  • Impact of Urbanization:

    • Urban development leads to habitat segmentation, reducing biodiversity, isolating populations, and disrupting dispersal patterns (Williams, 2006).
    • Decreased genetic diversity and weakened ecosystem resilience due to reduced invertebrate diversity (Walker et al., 2004).

  • Wetland Ecosystem Structure:

    • Vegetation regulates water flow and hydrological stability (Brinson & Malvarez, 2002).
    • Sediment dynamics affect water quality, increasing contaminants exposure (Horowitz, 2008).
    • Changes in hydrological patterns significantly impact species populations and nutrient cycles (Mitsch & Gosselink, 2015).

Invertebrate Indicators of Ecosystem Health

  • Invertebrates indicate wetland health and support other organisms (Wallace & Webster, 1996).
  • Constructed wetlands often have lower invertebrate diversity compared to natural wetlands (Declerck et al., 2011).
  • Research Significance: Evaluating invertebrate diversity in wetlands informs ecological conditions and health.

Site Comparisons

  • Lachlan Swamp:

    • Freshwater wetland linked to Botany Sands Aquifer, minimally impacted by urbanization.
    • Supports rich biodiversity with fluctuating water levels enhancing ecological support for invertebrates.

  • Randwick Environment Park (REP):

    • An ephemeral wetland affected by man-made disturbances such as sand mining, leading to reduced native vegetation.
    • Faces persistent threats from urbanization and invasive species.

Hypotheses

  • Hypothesis (H1): Randwick Environment Park has higher invertebrate biodiversity and/or abundance than Lachlan Swamp due to differing wetland ecosystems.
  • Null Hypothesis (H0): No significant difference in invertebrate biodiversity and abundance between the two parks.

Methodology

  • Leaf Litter Sampling:

    • 50L samples collected from both sites for invertebrate analysis.
    • Samples sorted, monitored, and identified by assigned groups; data compiled for analysis.

  • Data Analysis:

    • Analyzed using R software, focusing on species richness, relative abundance, and Shannon diversity index.
    • Data visualization through histograms and box plots to compare invertebrate diversity across sites.

Results Overview

  • Mean Abundance:

    • Centennial Park (CP): 170 individuals (SE: 26.7)
    • Randwick Environment Park (REP): 97 individuals (SE: 13.0)

  • Species Richness:

    • CP: Mean 17.8 (SE: 2.1) – lower variability.
    • REP: Mean 23.7 (SE: 2.3) – higher variability, indicating richer biodiversity.

  • Shannon Diversity Index:

    • CP: Mean 1.8 (SE: 0.2) – lower diversity.
    • REP: Mean 2.60 (SE: 0.26) – higher diversity and evenness in species distribution.

Conclusion

  • Results indicate greater invertebrate diversity and abundance in Randwick Environment Park compared to Centennial Park.
  • The findings highlight the importance of understanding invertebrate populations in urbanized environments for biodiversity conservation and ecosystem health.