18 January 2017
As discussed during the course introduction, landscape ecology aims to understand how patterns and processes, and the structure and form of a landscape influence each other. Landscape metrics (for an example of how landscape metrics are used in analyses, please refer to Lab 2: Exploring Fragstats) such as diversity, connectivity, and patch size quantify pattern which in turn gives insight into the processes by which they were produced. Below are some key ideas and concepts discussed in lecture relating to landscape patterns and processes.
- Scale
When attempting to determine the relationship between pattern and form. It is important to consider the effect of scale. This is because “phenomena occur on different scales of space, time, and ecological organisation [and] there is no single natural scale at which ecological phenomena should be studied” (Levin, 1992).
- Spatial autocorrelation
When the occurrence of an object/ event is influenced by the presence of another object/ event (eg. species A is more likely to appear in areas where species B is present), this results in a spatial pattern.
First-order process: a pattern developed in response to an environmental factor such as elevation or slope.
Second-order process: a pattern developed through interactions between objects/ events themselves eg. contagious disease or competition between species.
- Processes operating on a landscape
There are various processes that affect and create biogeographic patterns on a landscape:
– Abiotic processes eg. climate and topography
– Biotic processes eg. competition between species
– Disturbance eg. human activities, volcanic eruptions
Key words:
Stationarity – when the placement of an object of event does not change over space, it implies that the process regime (a characteristic behaviour of a system that is maintained by mutually reinforced processes or feedbacks) at work on the landscape is constant.
Isotropic pattern – the process at work does not exhibit a directional bias eg. soil type remains constant throughout a region.
Anistropic pattern – the process at work exhibits a directional bias eg. an increase in elevation with height.
References
Klinkenberg, B. (2017). Understanding landscape metrics. [Lecture notes]. Retrieved from http://ibis.geog.ubc.ca/courses/geob479/notes/Handouts/Lecture03.pdf