Grade 9 Academic Science – Biodiversity

Fragmentation and Non-Native Species

Section 3.4 and Section 3.5 – Pages 87-94

Habitat fragmentation is an ecological process in which a large patch of habitat is divided into smaller patches. In Wikipedia (2011), habitat fragmentation is the separation of an organism’s habitat such that the species or population is kept separate. In other words, it is when habitats that were once continuous become divided into distinct, separate and smaller units. Habitat fragmentation can occur naturally (e.g., volcanic eruption) or via human causes (e.g., construction of a highway, clearing land for farming).

According to Wikipedia (2011), habitat fragmentation includes five discrete phenomena:

·  Reduction in the total area of the habitat

·  Decrease of the interior : edge ratio

·  Isolation of one habitat fragment from other areas of habitat

·  Breaking up of one patch of habitat into several smaller patches

·  Decrease in the average size of each patch of habitat

Why is fragmentation a concern?

·  According to Al-jabber (2003), fragmentation is one of the major factors leading to declines in wildlife numbers, species and population.

·  Webb, et.al. (2002) suggests some species that are specific to a certain type or size of habitat may be unable to withstand the changes to habitat. Thus, vulnerability of a species is increased by fragmentation.

·  Populations become isolated in the smaller habitat patches. Migration is negatively impacted. As well, some species required different types of habitats at different life stages. If the habitats are isolated, these species are put at risk (Al-jabber, 2003).

·  In smaller patches, organisms become crowded…called “crowding of the ark.” This phenomenon can cause the population to crash (Meffe, et.al. 1997)

Task

You are an Environmental Planner. Wildlife populations in your assigned area have been declining for many years. You determine the problems are related to habitat fragmentation. You need to find solutions to reduce the impact of habitat fragmentation. Provide and explain three ideas.

See Table 1 on Page 88

On a global scale, habitat loss and fragmentation are second to climate change as the most serious threat to the sustainability of natural terrestrial ecosystems.

·  Habitat loss is the greatest concern in Africa, Latin America and the Caribbean. Why? Provide two ideas to suggest why ecosystems in these regions are most impacted.

Literature Cited

Al-jabber, Jabber M. 2003. Habitat Fragmentation:: Effects and Implications. (Online) Available: http://faculty.ksu.edu.sa/a/Documents/Habitat%20Fragmentation%20Effects%20and%20Implication.pdf

Meffe, G. K. and C.R. Carroll. 1997. Principles of Conservation Biology, 2nd ed. Sinauer Associate. Sunderland, MA.

Webb, J. K., B.W. Brook and R. Shine. 2002. What makes a species vulnerable to extinction? Comparative life-history traits of two sympatric snakes. Ecological Research, 17(1): 59-67.Webb

Wikipedia. 2011. Habitat Fragmentation. http://en.wikipedia.org/wiki/Habitat_fragmentation

Figure 1. Extinction of some species in Singapore between 1819 and 1990 due to habitat loss and fragmentation.

Task

In your own words, explain Figure 1.