Lecture 7: Understanding hydrological ecosystem services 3

Question 1

Hydrological ecosystem services and relevant processes : forest infiltration and flow regulation

Answer 1

Forested catchments will tend towards higher infiltration and thus throughflow and baseflow and less quickflow (surface flow). Lower peaks and longer lag, flow duration. Less flashy.

Deforested catchments behave similarly to urban catchments esp. if replacement land use is heavily trampled

Question 2

Hydrological ecosystem services and relevant processes : water storage and flow regulation

Answer 2

Large storage capacity provided by wetlands, floodplains (above ground) and paramos, forests (below ground) lead to lower flow maxima and higher minima.

Question 3

SDG 11.5 Water related disasters

Answer 3

Natural capital contribution to total realized storage capacity ES, supporting urban popns

Storage capacity on non-human land uses upstream of urban populations in floodplains
Population benefitting: 0.3b

Question 4

Hydrological ecosystem services and relevant processes : water purification

Answer 4

Can occur simply because the low inputs of fertiliser, manures, pesticides, herbicides on ‘natural lands’ mean that pure flows dilute contaminated flows from surrounding agriculture

Also wetlands, soil, groundwater filtration act to purify water.

Question 5

Environmental vs. ecosystem services : cloud forest example

Answer 5

An environmental service:
Cloud forests occur underneath persistent ground level cloud in the tropics. This cloud generates:
high rainfall inputs
low evapo-transpiration

The pan-tropical average cloud-forest water balance is 452 mm/yr cf 124 mm/yr for the tropics as a whole. This is a function of the climate in which the cloud forest sits not the cloud forest itself and would occur even in the absence of the forest.

An ecosystem service:
Cloud forests strip passing cloud/fog water very efficiently and this water ends up in the rivers. If the cloud forests are replaced by pasture, this stripping does not occur and the extra water is lost. This service is dependent on the ecosystem as well as the environment.

Question 6

Seasonal snowmelt in the Andes and Himalaya

Answer 6

provide water in the dry season to communities downstream: but an environmental service not an ecosystem service