Vulnerability and resilience of ecosystems - Human activity and speed of
change.
An ecosystem’s________________, ________________, ___________and
linkages are controlling factors determining its vulnerability and resilience when
conditions change or natural stresses occur. The alpine ecosystem is a good
example of this. Alpine ecosystems are found in mountainous areas of low
temperatures, where the majority of precipitation falls as snow.
Biodiversity can be considered on three levels:_____________,
_____________and __________________. Ecosystems with low levels of
biodiversity are more vulnerable than those rich in biodiversity. Alpine
ecosystems, for example, have comparatively low species diversity, meaning
they have lower resilience and recover more slowly from stress. The highly
specialised organisms characteristic of alpine ecosystems may be more
vulnerable than the ecosystem as a whole, but this will still affect the ecosystem
function, as food webs can be easily destroyed.
Diverse ecosystems are also more resilient, because there is a range of
alternative pathways for ecological processes if one pathway is damaged.
Genetic diversity leads to greater resilience, as it increases the chance that
some members of the species will have characteristics that aid survival if
conditions change. When a large-scale natural stress (eg. drought) or human
impact (eg. land clearing) occurs, large numbers of plants and animals are
destroyed, leading to further decreased biodiversity, making the ecosystem
more vulnerable to further natural stress.
The extent of an ecosystem can affect its vulnerability and resilience, and itself
be affected by ________________. The vertical zonation of alpine ecosystems
is an example of microclimate variation, which can affect ecosystem extent, as
microclimates restrict the area of the ecosystem. This means that the ecosystem
is more vulnerable. Alpine ecosystems generally have large populations of a
relatively small variety of species spread out over the area. This means that a
small-scale ______________such as a landslide will have little impact on the
ecosystem, as only a small area is destroyed. However, a large-scale stress
such as a fire will have a devastating impact on the alpine ecosystem. Also, if
ecotones are damaged by fire or other stresses, the buffer zone of the
ecosystem is destroyed, making it more vulnerable to further damage.
The _________________of an ecosystem can also make it vulnerable to
damage, and determine its resilience. For example, alpine ecosystems in
Australia are located in areas above 2000m, therefore subject to extremes of
cold, which mean low biodiversity and limited vegetation. Extreme conditions
such as this mean that organisms in the ecosystem are highly specialised. The
greater the degree of specialisation, the more vulnerable the organisms are to
changes in conditions. This means that __________________such as fire or
droughts will have a devastating impact. The location of the alpine ecosystem
makes avalanches and landslides more common, however the damage from
these is concentrated in a small area. Due to the harsh conditions that
characterise the alpine region, the _______________of this ecosystem is low.
Another locational factor influencing the vulnerability of an ecosystem is its
proximity to large ____________of people, making it increasingly vulnerable to
pollutants, land clearing etc.
High levels of ______________between organisms within an ecosystem
increase the ecosystem’s ability to ____________change; it is more resilient.
The relatively low number of linkages within the alpine ecosystem makes it
much more vulnerable to change and less resilient. The relatively low
biodiversity in alpine ecosystems means that producers and consumers cannot
be easily replaced by other to fulfil a similar function. Therefore the
_______________in the alpine ecosystem are fragile, and food webs are
extremely vulnerable to damage. Also, the animals characteristic of alpine
ecosystems have highly specific food sources, making them more vulnerable to
disturbances. For example, fires may destroy certain types of vegetation that an
animal species is dependent on, leading to possible extinction.
CLOZE PASSAGE
populations , species diversity, large-scale stresses, linkages, genetic diversity,
resilience, location, natural stress, location , ecosystem diversity, linkages,
absorb, disaster, biodiversity, extent