Presentation is loading. Please wait.

Presentation is loading. Please wait.

Habitat fragmentation #I 14 September 2009 – Pringle lecture l. Components of fragmentation A. Reduction in total amount of habitat type B. Apportionment.

Similar presentations


Presentation on theme: "Habitat fragmentation #I 14 September 2009 – Pringle lecture l. Components of fragmentation A. Reduction in total amount of habitat type B. Apportionment."— Presentation transcript:

1 Habitat fragmentation #I 14 September 2009 – Pringle lecture l. Components of fragmentation A. Reduction in total amount of habitat type B. Apportionment of remaining habitat into smaller and more isolated patches II. What constitutes a barrier? III. Biological responses to habitat fragmentation A. initial exclusion B. isolation C. island-area effects D. edge effects IV. The case of migratory songbirds V. Protecting wildlife/biotic integrity in a fragmented landscape: Challenges facing remnant natural areas

2 I. Components of Habitat Fragmentation A. Natural heterogeneity vs fragmentation caused by humans (rich internal patch structure vs simplified patches) B.Biota in human-altered fragmented landscapes are affected at different levels of biological organization a. changes in gene frequencies of local populations b. continent wide changes in species distribution and ecosystems (Panda Example)

3

4

5

6 Slide 6 Habitat loss and fragmentation Increasingly leading to ex situ breeding and conservation efforts

7 Components of habitat fragmentation: apportionment of remaining habitat into smaller and more isolated fragments

8 II. What constitutes a barrier? Species Specific Cumulative effects -dams in rivers -roads in parks -canals -power lines -fences -fire lands -other ???

9 Dams as barriers

10

11 Roads as barriers

12

13 Road Impacts: Animal vehicle collisions cause 200 deaths per year in the US and cost US 1 billion annually in property damage 35 million reptiles and frogs per year in Australia 43,002 deer in Pennsylvania in ,306 deer in Ohio in 2002 >10,000 deer per year in Kansas 102 black bears in North Caroina in 2002 Ecological hot spots of mortality:

14 Roads as avenues for invasion by humans and exotic species Initial road 20 yrs later

15 The case of hedgerows in Britain and the importance of protecting historical landscape features in highly fragmented landscapes What constitutes a barrier for domestic livestock is a corridor for ‘wildlife:

16 The ‘wildlife’ in hedgerows: Many small mammals house mice, door mice, shrews, weasels, voles Most of Britain’s woodland birds use hedgerows at least some of the time High diversity of plants relative to surrounding countryside Greater number of species in older hedges

17 In Britain, roughly a quarter of the hedgerows (96,000 miles) were removed between An additional 56,000 miles lost between

18

19

20

21 III. Biological responses to habitat fragmentation A. initial exclusion B. isolation C. island-area effects D. edge effects

22 Initial exclusion, isolation and consequent loss of biota

23 Reindeer in southern Norway Island Area Effects: Competition and overgrazing

24 Edge Effects temperature, light, humidity, wind, fire predation exotic species disease pollution

25

26 Edge Effects: increased vulnerability to predation

27

28

29

30 Nest predators in fragmented Landscapes

31

32 Cowbirds parasitize the nests of >200 bird species Originally restricted to the northern part of the Great Plains

33

34

35 Endangered Kirtland’s warbler - highly parasitized by cowbirds

36

37

38

39 Brown headed cowbird chick in nest of yellow warbler Smaller-bodied host birds have less chance of raising any of their own young than do larger-bodied birds

40 Solutions?

41 Humanely disposing of cowbirds

42 Edge effects: Greater vulnerability to invasion by exotics

43 Edge Effects: Enhanced incidence of infectious disease

44 Are migratory song bird declines in North America primarily a result of habitat fragmentation in temperate regions or habitat destruction in the tropics? Where have all the birds gone?

45

46

47

48 Decline of migratory songbirds: Reproductive failure in temperate breeding areas due to habitat fragmentation Destruction of tropical habitat

49 Protecting migratory songbirds: Recognizing the importance of intact source areas- i.e. large areas of intact forest which serve as refuges producing surplus birds that can later disperse and re- populate sink areas Restoring forests in areas that are currently sinks

50 Habitat fragmentation #I I. Components of fragmentation A. Reduction in total amount of habitat type B. Apportionment of remaining habitat into smaller and more isolated patches II. What constitutes a barrier? III. Biological responses to habitat fragmentation A. initial exclusion B. isolation C. island-area effects D. edge effects IV. The case of migratory songbirds V. Protecting wildlife/biotic integrity in a fragmented landscape: Challenges facing remnant natural areas


Download ppt "Habitat fragmentation #I 14 September 2009 – Pringle lecture l. Components of fragmentation A. Reduction in total amount of habitat type B. Apportionment."

Similar presentations


Ads by Google