Page 13 - Freshwater-Biology-and-Ecology-Handbook

The health of our water ecosystem is critical to the environment on which we
depend and is therefore directly related to human wellbeing. We increasingly
realise that the ultimate test of ecosystem health is to monitor the biological and
ecological indicators present in the environment. We must protect this precious
natural resource and manage the environment sustainably, using long-term
river basin planning and management. These principles are enshrined in UK and
European Union (EU) legislation under the Water Framework Directive (WFD). (1)

What we value as ‘the environment’ is widely objectives with chemical and physical
thought of as a physical entity, but it is in fact objectives (including hydrological objectives)
mainly biologically driven. It is the natural to make it easier to regulate the release of
biota and its ecological interactions with the industrial, agricultural and domestic waste,
abiotic environment that maintains the health and the abstraction of water.
of our environment, essential to our existence.
These beneficial processes are known as To prioritise our regulatory activities and to
ecosystem services. We can damage the focus essential environmental monitoring,
physical environment, but it is the biotic we assess the risks and pressures on
component of freshwaters that is particularly aquatic environments. These pressures are
sensitive to damage from human activity. summarised in Figure 1. Understanding the
Not only pollution, but activities such as land geographical, geological and anthropogenic
use, abstraction, impoundment, physical pressures within a river basin is often the
modification, air pollution, climate change and starting point for river basin planning.
allowing alien invasive species and diseases In WFD terms, this is known as ‘river basin
to spread: all affect the natural biota and characterisation’. This allows chemical and
therefore the health of aquatic environments. physical objectives to be set at levels that
support the biota necessary to achieve our
We manage the pressures caused by human environmental objectives, and protect
activities in an integrated way using ecological human health.
quality objectives. The best way to define
ecological quality and the objectives based Within river basins we set our ecological
on it, is to focus on the actual composition of objectives at a level that maximises the
the biota. Specifically, the degree to which benefits to our wellbeing, including our health
biota are impacted by human activities. and economy; in other words, at a level that
maximises the ecosystem services that
We define biological quality as its proportional the environment provides. We try to avoid
deviation from a theoretical near-natural over-exploitation and unnecessary damage
condition. The deviation is a measure of because this reduces the resilience of the
human impact. Biological monitoring provides ecosystem and its ability to recover from
a direct way to measure environmental quality minor damage, and may cause a long-term
in relation to biological and ecological quality or permanent reduction in the services that it
objectives. In effect, we are measuring the provides. Meeting these ecological objectives
natural capital that provides the ecosystem aims to ensure that the water environment is
services. We support our ecological managed as sustainably as possible.

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