IELTS Academic Practice Test 20

Beneath the forest floor exists one of nature's most remarkable communication systems, so vast and intricate that scientists have only recently begun to understand its complexity. Mycorrhizal networks are associations between fungi and plant roots that form an underground web connecting trees, shrubs, and other plants across entire ecosystems. These fungal networks, sometimes called the "wood wide web" by researchers, operate as a biological internet, transferring nutrients, water, and chemical signals between plants that are separated by considerable distances. The relationship between fungi and plants is fundamentally symbiotic. Fungal filaments called hyphae penetrate plant root cells and extend outward into the soil, dramatically expanding the root system's reach. In return for providing carbon-rich sugars through photosynthesis, plants receive phosphorus, nitrogen, and other minerals that fungi are uniquely capable of extracting from soil particles and organic matter. This trade is so efficient that many plants would struggle to survive without their fungal partners. Scientists estimate that approximately ninety percent of terrestrial plant species form mycorrhizal associations, making these networks nearly universal in natural ecosystems. The discovery of how these networks facilitate plant communication revolutionized ecological understanding. In the 1990s, research demonstrated that trees could transfer resources through fungal networks to support distressed neighbours. A landmark study showed that Douglas fir trees could even redirect resources toward their own offspring when connected through fungal networks, suggesting that plants possess a form of kin recognition. Subsequent research revealed that plants under insect attack send chemical distress signals through the network, warning neighbouring plants to activate defensive compounds before herbivores reach them. These pre-emptive defences reduce damage significantly, proving that the network operates as an early warning system. Different types of fungi form different mycorrhizal relationships. Ectomycorrhizal fungi wrap around root surfaces, creating a sheath-like structure, and are particularly common in temperate forests dominated by conifers and hardwoods. Endomycorrhizal, or arbuscular, fungi penetrate root cells directly and are more prevalent in grasslands, tropical forests, and agricultural soils. A single tree may host multiple fungal partners simultaneously, creating a complex web of interconnections. Some fungi form exclusive partnerships with specific plants, while others associate with dozens of different species, functioning as universal connectors within the network. The ecological implications of mycorrhizal networks extend far beyond individual plant survival. Network connectivity influences forest resilience and recovery after disturbances such as fire or disease. Mature trees can support younger trees and competing species through the network, promoting overall forest stability and biodiversity. In declining forests, a breakdown of fungal networks can amplify the collapse of the ecosystem, as plants lose their primary nutrient delivery systems and communication channels. Conversely, forests with healthy, well-established networks demonstrate remarkable recovery capacity. Human activities increasingly threaten mycorrhizal network integrity. Heavy tillage and ploughing in agriculture destroy fungal structures, leading to dependence on chemical fertilizers. Atmospheric pollution, particularly nitrogen deposition, can disrupt the balance of fungal communities. Certain fungicides and pesticides directly harm beneficial fungi, while monoculture plantations support far fewer fungal species than diverse natural forests. Climate change alters the geographic distributions of both plants and fungi, potentially mismatching partners that have co-evolved for millennia. Conservation efforts are beginning to recognise the critical importance of mycorrhizal networks. Land managers now consider fungal diversity when planning reforestation, sometimes inoculating seedlings with native fungal species before planting. Reducing chemical inputs and promoting diverse plant communities helps restore network complexity. Research into mycorrhizal networks also promises applications in sustainable agriculture, where managed fungal inoculation could reduce fertilizer requirements while improving crop resilience. As our understanding of these hidden networks deepens, it becomes increasingly clear that protecting plant-fungal partnerships is essential for maintaining forest health, biodiversity, and the ecosystem services upon which human societies depend.

Over the past two decades, a growing movement known as urban rewilding has emerged in cities across Europe and North America, fundamentally challenging conventional approaches to urban planning and green space management. Unlike traditional gardening or landscaping, which impose human order onto nature, urban rewilding deliberately allows wild plants and animals to reclaim fragmented urban spaces—from abandoned industrial sites to neglected parks and road verges. Proponents argue that this approach offers a powerful antidote to biodiversity loss while simultaneously reducing municipal maintenance costs. The philosophical roots of urban rewilding trace back to landscape architect James Corner's concept of 'landscape as process' and the Dutch ecologist Piet Oudolf's naturalistic planting principles, which emphasize working with ecological succession rather than against it. However, the movement gained substantial momentum only after the 2011 publication of Isabella Tree's research on the Knepp Estate in Sussex, England, where a conventional agricultural farm was deliberately allowed to return to wilderness. The documented rapid return of previously absent species—including multiple butterfly types, breeding birds, and even large herbivores introduced as ecosystem engineers—inspired urban planners worldwide to question whether cities could support similar ecological recoveries on smaller scales. In practice, urban rewilding manifests in diverse forms. Berlin has become a leader in the field, with over 5,000 designated 'Wiese' areas—essentially meadows—replacing mowed grass lawns throughout the city. These spaces require minimal intervention: native wildflower seeds are sown, invasive non-native species are removed, and then the land is left to develop naturally. Similarly, the city of Copenhagen has converted portions of its harbor-front industrial zones into wetland reserves that now attract wading birds and aquatic insects previously unseen in urban contexts. London's Camley Street Natural Park, established in 1984 as one of the earliest urban nature reserves, pioneered the model by allowing a derelict industrial site to become a self-sustaining wetland ecosystem. However, urban rewilding is not without controversy and challenges. Critics raise legitimate concerns about safety and public health. Unmanaged vegetation can harbor disease vectors such as ticks and mosquitoes, and dense undergrowth may increase accident risks or provide cover for crime. Additionally, urban rewilding can inadvertently favor invasive species that thrive in disturbed environments, potentially degrading rather than enhancing local biodiversity. Some ecologists argue that rewilding efforts that lack scientific monitoring become pseudo-rewilding—aesthetically appealing but ecologically superficial. A more nuanced perspective recognizes that urban rewilding requires careful calibration rather than complete abandonment of management. The concept of 'rewilding with intervention' has emerged, wherein practitioners selectively remove dominant invasive species, introduce native plants and pollinators, and maintain adaptive monitoring protocols. Research conducted by the University of Sheffield on urban meadows demonstrated that actively seeded wildflower plots achieved significantly higher species richness—averaging 24 native plant species per square meter—compared to passively abandoned sites, which averaged only 8 species. This suggests that some degree of informed human intervention enhances ecological outcomes. Another critical dimension involves the relationship between urban rewilding and social justice. Affluent neighborhoods often receive disproportionate investment in green infrastructure, while lower-income areas face environmental degradation. Urban rewilding advocates increasingly emphasize 'just rewilding'—prioritizing initiatives in underserved communities where residents have limited access to nature and where industrial legacies create both ecological and public health burdens. Cities like Detroit and Pittsburgh, scarred by decades of deindustrialization, have embraced rewilding as a mechanism for reclaiming abandoned industrial spaces and restoring community agency. The ecological benefits, when properly implemented, are substantial and measurable. Rewilded urban sites function as 'biodiversity stepping stones,' creating connected networks that allow species migration across otherwise fragmented landscapes. Insect populations, crucial for pollination and food chains, have shown marked increases in rewilded areas. Urban soils in rewilded sites experience improved structure and microbial diversity due to reduced compaction and chemical inputs. Additionally, these spaces enhance urban cooling, reduce stormwater runoff, and improve air quality—co-benefits that support human wellbeing alongside ecological restoration. Looking forward, urban rewilding will likely become increasingly integrated into mainstream city planning rather than remain a marginal practice. Municipal governments are beginning to allocate specific percentages of public land to rewilding initiatives, and private developers are incorporating rewilded corridors into residential and commercial projects. However, success depends on moving beyond romanticized notions of 'untouched wilderness' and instead embracing rewilding as a deliberate, science-informed strategy that balances ecological restoration with public safety, social equity, and community engagement. The next phase of urban rewilding must be adaptive, inclusive, and grounded in rigorous monitoring and adaptive management—transforming cities not into pristine nature reserves, but into resilient, biodiverse, livable spaces for humans and other species alike.

Urban rewilding—the deliberate reintroduction and cultivation of wild plant and animal species within densely populated cities—represents one of the most counterintuitive environmental movements of the twenty-first century. Emerging from the intersection of ecological restoration, urban planning, and community activism, this phenomenon challenges the traditional binary opposition between wilderness and urbanity, suggesting instead that cities themselves can serve as functional ecosystems rather than mere repositories for human infrastructure. Yet this optimistic narrative conceals profound tensions between ecological purists, pragmatists, and municipal administrators, each envisioning radically different outcomes for the same initiatives. The movement's intellectual foundations rest partly upon the recognition that contemporary urban environments, contrary to popular assumption, already harbour substantial biodiversity. Pigeons, rats, foxes, raccoons, and countless insect species have long inhabited cities, albeit often regarded as pests or nuisances rather than ecological actors worthy of consideration. Urban rewilding inverts this perspective: rather than perpetually eradicating these populations through pest control, it proposes coexistence, even facilitation, of non-native and semi-wild species within human-dominated landscapes. Proponents argue that green corridors—linear networks of vegetation linking fragmented habitats—can mitigate the isolation of species populations, reduce heat island effects in concrete-dominated areas, and improve human psychological well-being through increased nature contact. Cities including Barcelona, Singapore, and Milan have invested substantially in such infrastructure, converting rooftops into wildflower meadows and transforming redundant industrial sites into wetland reserves. However, the practice raises contentious questions about ecological authenticity and intervention ethics. Critics contend that urban rewilding frequently represents a technologically-mediated, curated form of nature—essentially a simulacrum orchestrated by municipal authorities—rather than genuine wilderness regeneration. The distinction matters profoundly: a deliberately designed pollinator garden operating according to horticultural specifications differs substantially from self-organised ecological succession occurring without human management. Furthermore, the species selected for urban rewilding often reflect contemporary aesthetic preferences or functional utility rather than historical ecological appropriateness. In London's Barbican Conservatory, for instance, planted ecosystems feature Amazonian species and Southeast Asian flora, creating an essentially artificial biotic community disconnected from local evolutionary and biogeographic contexts. This curatorship extends to the problematic omission of less photogenic species—unglamorous invertebrates, parasitic fungi, and decomposer organisms that perform essential ecological functions but generate neither public enthusiasm nor funding. Another tension emerges from the potential substitution problem: municipal investment in urban green space might paradoxically reduce political pressure for wilderness protection in genuinely wild areas. If urbanites satisfy their conservation impulses through weekend visits to managed botanical gardens or participation in community planting initiatives, governmental resources might be redirected away from protecting genuine remnant ecosystems and endangered species habitats. The opportunity cost remains largely invisible, embedded within budgetary allocations and policy priorities that receive minimal public scrutiny. Conversely, some scholars propose that urban rewilding might catalyse broader ecological consciousness, creating constituencies supportive of environmental protection precisely because they have developed experiential familiarity with natural processes through urban engagement. This educational function could prove particularly significant in societies where majority populations now inhabit cities, potentially divorcing citizens entirely from ecological understanding. From this perspective, even imperfect, managed urban ecosystems represent valuable pedagogical instruments. The ecological effectiveness of rewilding initiatives remains contested territory empirically. Rigorous longitudinal studies measuring biodiversity outcomes, species persistence, and functional ecosystem services remain surprisingly sparse, particularly compared to the proliferation of anecdotal reports and promotional narratives. Some investigations suggest that rewilded urban sites achieve only marginal improvements in species diversity relative to conventional landscaping, whilst others document substantial increases in pollinator abundance and insectivorous bird populations. These variable outcomes partly reflect differing methodologies and measurement parameters, but also indicate genuine contextual variability: success in temperate climates with legacy biodiversity differs markedly from initiatives in arid regions or cities built atop previously homogenised agricultural lands. Looking forward, urban rewilding will likely intensify, driven by climate change adaptation imperatives, biodiversity loss awareness, and the technological capacity to monitor and manage urban ecosystems with increasing precision. Yet the movement's philosophical foundations require deeper interrogation. Urban rewilding ultimately represents not nature's reclamation of cities, but rather cities' reclamation of nature—a reframing that honestly acknowledges human agency and control whilst simultaneously questioning whether genuine ecological integrity can exist within environments fundamentally structured by human economic logic and aesthetic preference. Resolving this paradox demands intellectual humility, rigorous empirical assessment, and recognition that urban ecosystems constitute a novel category requiring frameworks distinct from both wilderness ecology and conventional landscape management.