2. BISC530: Biology Conservation Kedong Yin  Introduction  Habitat fragmentation  Demographic Processes on heterogeneous landscapes: Metapopulation dynamics Key references: Meffe and Carroll and et al. 1997. The Principles of Conservation Biology. Sinauer Assoc. Inc. McCullough, DR. 1996. Metapopulation and Wildlife Conservation Chapter 9 http://teaching.ust.hk/~bisc530/

3. Biological Conservation Genetic material Gene pools Species Populations Communities Habitats Ecosystems Biosphere Focal levels of Conservation Introduction

4. 1.The diversity of organisms is good 2.The untimely extinction of populations and species is bad 3.Ecological complexicity is good 4.Evolution is good 5.Biological diversity has intrinsic values Some postulates in conservation biology:

5. Biodiversity  Species diversity remain to be the most important one  Focusing on important species may provide short cuts to conservation  Keystone taxa: predominating ecological role in community they may help to characterize  Umbrella taxa: species providing “shelter” for many others  Flagship taxa: public appeal  Indicator taxa: environmental change

6. Guiding Principles for Conservation Biology Principle 1: Evolution is the basic axiom that unites all of biology (the evolutionary play) Principle 2: The ecological world is dynamic and largely non-equilibrial (the ecological theatre) Principle 3: The Human presence must be included in conservation planning (Humans are part of the play)

7. Habit Fragmentation: 1.Habitat fragmentation 2.Fragmentation and Heterogeneity 3.The Fragmentation Process 4.Insularization and Area effects 5.Biological Consequences of Fragmentation

8. Historical lessons on habitat loss:  Classified Greek period -- the barren landscape of deserts in the middle east (Turkey, Syria, Irag and Iran) used to be fragile woodlands  Humid tropics -- shifting practices with gaming, rotating practices in farming, not possible in crowded world today  Europe -- Great Britain, many forests destroyed by 12th century, public forests eliminated by the late 18th century, due to the demand for charcoal supply

9. 1. Habitat fragmentation:  Reduction of the total amount of a habit type, or perhaps of all natural habitat in a landscape  Divide a continuous landscape into smaller, more isolated patches Critical habitat -- a specific area within the species range with physical or biological features either (1) essential to conservation of the species or (2) which may require special management considerations or protection

10. Fig. 9.1 Changes in wooded area of Cadiz Township, Green Country, Wisconsin, during the period of European settlement. Wooded area 18311882 19021950

11. 2. Fragmentation and Heterogeneity Patches (heterogeneity) vs continuous (homogeneous), a matter of scales: zoom in or zoom out A side view of the mountain Different vegetations

12. High mortality patch Medium mortality patch Low mortality patch Large disturbances like fires create a course grained pattern Small disturbances – a fine-grained pattern Different 7 phases of canopy gaps by death and fall of individual trees 10 km 1 km

16. 2. Fragmentation and Heterogeneity  Spatial scale (physical gradients, light, moisture, elevation)  Temporal (seasonality)  Disturbances (fires, storms)  Microhabitats Patches (heterogeneity) vs continuous (homogeneous), a matter of scales: zoom in or zoom out So, if habitat heterogeneity is good for diversity, what is the difference between human-fragmented and natural patchy landscape?  Internal structure  Edge effects  Barriers  Evolutionary

17.  Biological integrity -- Ecological system  Disruption of continuity in pattern or processes Spatial scale Temporal scale 3. The Fragmentation Process: Gap formation Fragmentation A B C

18. Typical Habitat Fragmentation A ranch subdivided into ranchettes Building 1957 19831994

19. Fragmentation Population Density Roads Fences Subsidized predators Exotic Species Nuisance problems Wildlife generalists Wildlife Specialists Increase Decreases in # Effects when land is subdivided into ranchettes

20.  Area-species relationship: difference between island and a patch of habitat, or  A phenomenon of statistic sampling  The equilibrium theory of island biogeography 4. Insularization and Area effects: S=cA Z or Log S = Log C + z Log A S=species richness, A= area, c- constant S A Log S A Island Quadrats

21. Probability of occurrence of birds vs forest areas

22. Equilibrium Theory of Island Biogeography: Species richness is the balance between colonization and extinction rates LowHigh FS NS FL NL ColonizationExtinction Far: F Large: L Near: NSmall: S Species Richness # Rate of Colonization or Extinction

23. 1) Speciation 2) Initial exclusion: 3) Barriers and Isolation 4) Crowding effects 5) Local and Regional Extinctions 6) Species vulnerable to fragmentation 7) Edge Effects 8) Changes in Species Composition 9) Effects on Ecological Processes 5. Biological Consequences of Fragmentation:

24. 1) Speciation Speciation: a process a new species is formed. Speciation process is ultimately a genetic divergence between populations through time, reflecting local adaptation How selection works: giraffe long neck

25. Selective pressure toward a longer-necked, taller animal Selective pressure stops Many generations Short-necked animals starve and die. Gene for shorter neck does not enter gene pool

26. Gradual allopatric speciation Barrier A A A A A A AA AA A AAA A A A A A A A AAA AB B B B B A A A A A B B B B B Founder model or Quantum Speciation A A A A A AA AA A A A A A A AA AA A A A A A A AA AA A A A A A B B B B

27. Gradual Allopatric Speciation: Arctic vs Gray fox Subpopulations spread northward and southward and separate Conditions differ giving different selective pressures causing evolution into different species Adaptations to cold climate: heavy fur; short tail, ears, legs, and nose; light color Adaptations to warm climate: thin fur; long tail, ears, legs, and nose; dark color Arctic FoxGray Fox

28. Exmaple of quantum speciation of finches Darwin’s finches. The similarities among these birds attest to their common ancestor. Selective pressures adapting subpopulations to feed on different foods has caused their modification and speciation. Warbler Cactus Ground Sharp-Beaked Ground Vegetarian Large insectivorous Small insectivorous Woodpecker Sharp-Beaked Ground Small Ground Medium Ground Large Ground

29. Geographic modes of speciation: 1) Gradual allopatric speciation Reproductive isolation is a result of divergence. If divergence is relatively short, the two groups comes into second contact-hybrid-no advantage -stable. If long, hybrids -- natural selection works -- become distinguishable specie. 2) Founder model or quantum speciation  small gene pool  gene drift -- genetic drift--rapid and substantial genetic change  speciation -- rapid

30. Effects of fragmentation of habitats on the speciation Two scenarios: 1) quantum speciation occurs rapidly and results in several species 2) local extinction -- more quickly than speciation A A A A A AA AA A A A A A A A A A C D A B A A A A A 1 2

31. 2) Initial Exclusion One of the most rapid and obvious effects of fragmentation: elimination of the species by the initial exclusion Home ranges are destroyed, endemic species are sometimes quite restricted in its distribution, many rare species are endemics with narrow distributions Species with narrow distribution are vulnerable when their habitat is fragmented Endemic species: species only exist in this country, not in other countries; or in this area not in other areas.

32. A B A constellation of separate habitat patches may be critical to the survival of individuals or populations. When a species requires several patches (green area) to survival, then species in site A would survive better. A species require several patches to survive A B 3) Barriers and Isolation

33. A B Many animals require a suite of different habitats or resources to survive. A population in Site A in the proximity of different habitat B would survive better than in Site B. A species require different habitats (A and B) to survive A B

34. Roads as barriers to the movement of small animals N>100 N>50 N>20 Beetle density Carabid beetles releasing experiment Lines – movement of marked bettles between capture and recapture

35. 3) Barriers and Isolation A constellation of separate habitat patches – critical to the survival of a population A mix of different habitats with different resources- important Barrier: species specific Roads as a major barrier to many species Barrier effects are both relative and cumulative Structural contrast between fragmented habitats and the matrix for the species is one measure of fragmentation, as the landscape around fragments is altered, the functional isolation of these fragments increases Dams or other marine engineering projects

36. 1) Speciation 2) Initial exclusion: 3) Barriers and Isolation Barriers are species specific Relative and cumulative 4) Crowding effects 5. Biological Consequences of Fragmentation:

37. 4) Crowding Effects Population densities may initially increase in the fragment when the fragment is isolated This packing phenomenon – “crowding on the ark” The initial increase is often followed by the population collapse

38. 1) Speciation 2) Initial exclusion: Home ranges are destroyed, endemic species are sometimes quite restricted in its distribution 3) Barriers and Isolation Barriers are species specific Relative and cumulative 4) Crowding effects 5)Local and Regional Extinctions Even common species can disappear from the fragments when the fragments are altered. 5. Biological Consequences of Fragmentation:

39. 1) Speciation 2) Initial exclusion: Home ranges are destroyed, endemic species are sometimes quite restricted in its distribution 3) Barriers and Isolation Barriers are species specific Relative and cumulative 4) Crowding effects 5) Local and Regional Extinctions 6) Species vulnerable to fragmentation 5. Biological Consequences of Fragmentation: Species vulnerability  Abundance  Extent of ecological specialization  Geographical range

40. 6) Species vulnerable to fragmentation Naturally rare species: a)Species with limited or patchy geographic distributions (e.g. endemic species) b)Species with low population densities (e.g. animals with a large home range) Wide-ranging species: large carnivores needs a large area for food hunting or seasonal movement Nonvagile species: species with poor dispersal abilities may not travel far from their birth place, e.g. many insects of old growth forests Species with low fecundity: species with low reproductive capacity

41. 6) Species vulnerable to fragmentation Species with short life cycles: more vulnerable than longer-lived species Species dependent on patchy or unpredictable resources or otherwise highly variable in population size Grounded Nesters: nesting on or near the ground Large-patch or interior species: species living in the interior of a habitat, thus vulnerable to fragmentation of their habitat Species vulnerable to human exploitation or persecution

42. 1) Speciation 2) Initial exclusion: Home ranges are destroyed, endemic species are sometimes quite restricted in its distribution 3) Barriers and Isolation Barriers are species specific Relative and cumulative 4) Crowding effects 5) Local and Regional Extinctions 6) Species vulnerable to fragmentation 7) Edge Effects 5. Biological Consequences of Fragmentation:

43. 7) Edge Effects There is edge if a habitat island is different from the surrounding landscape There is a gradient of environmental factors across the edge Ecological trap: animals are attracted to edge habitat The structural contrast to the surrounding landscape is an indicator of the strength of edge effects The ratio of the edge length to the interior area is a measure of the edge effects Loss of quail eggs

44. A comparison of breeding success of fragmentation sensitive birds (16 species) in two forest fragments with similar total areas, but vastly different core areas (forest interior). A is entirely edge habitat (light); B contains 20 ha of interior habitat. No birds bred successfully 6 species / 16 species bred in core area A B 39 ha 47 ha 20 ha

45. 1) Speciation 2) Initial exclusion: Home ranges are destroyed, endemic species are sometimes quite restricted in its distribution 3) Barriers and Isolation Barriers are species specific Relative and cumulative 4) Crowding effects 5) Local and Regional Extinctions 6) Species vulnerable to fragmentation 7) Edge Effects 8) Changes in Species Composition 5. Biological Consequences of Fragmentation:

46. 1) Speciation 2) Initial exclusion: Home ranges are destroyed, endemic species are sometimes quite restricted in its distribution 3) Barriers and Isolation Barriers are species specific Relative and cumulative 4) Crowding effects 5) Local and Regional Extinctions 6) Species vulnerable to fragmentation 7) Edge Effects 8) Changes in Species Composition 9) Effects on Ecological Processes 5. Biological Consequences of Fragmentation:

47. Species Persistence in a fragmented landscape: 3 options  Survive well or thrive in a matrix of human land uses: weedy species  Maintain viable population within individual habitat fragments: species with a small home range  Highly mobile: some birds

48. Habit Fragmentation: 1.Habitat fragmentation 2.Fragmentation and Heterogeneity 3.The Fragmentation Process 4.Insularization and Area effects 5.Biological Consequences of Fragmentation