Humidity

	The measurement of humidity is limited.
	Hydrometer should be used. Eg. wet bulb and dry bulb thermometer.

Temperature

	The temperature difference between soil and air is inaccurate as the alcohol-in-glass thermometer has a course scale only.
	Electronic thermometer can be used to overcome this limitation.

Topography

	The depths of two ranging poles in soil cannot be measured. Human error is made during measurements.
	Mark the apparatus before use.

(B) Counting species

Seasonal variations

	The populations of animal and plant species vary from season to season because of their reproduction periods. The environmental changes affect the populations of species.
	Measurement should be taken in different seasons in order to obtain the mean.

Belt transect

	The area we took for investigation cannot reflect the whole distribution.
	Several investigations should be done to have an average result.

(C) Pollutions

Land pollutions

	Disposal of litter and rubbish damages the environment. The household and farmland nearby produce domestic wastes and untreated animal waste. These affect the life styles of mangrove species in Ting Kok.
	Education, legislation and establishing conservation areas.