Objectives

1. Objectives Conservation approaches: populations/species entire habitats Habitat destruction/fragmentation causes much extinction Conservation biology relates to landscape and community ecology Plans for preserves Size, number, shape, pattern Stepping stones, corridors Preserve community structure

2. Conservation Biology IB 451 Spring 2011 Landscape Ecology NRES 465 Spring 11

3. Conservation Planning: Approach 2 Preserve habitats/areas, especially ‘biodiversity hotspots’ high species number high endemism

4. Endemic species: restricted to small geographic area; especially prominent on islands

5. Deterministic causesof extinctions:the ‘evil quintet’ 1 habitat destruction and fragmentation (67% of cases) 2 overkill (overexploit) 3 chains of extinction introduced species emerging diseases

6. Habitat changes caused by human land use limit conservation strategies.

7. Habitat reduction and fragmentationlead to endangered species

8. Habitat reduction and elimination Some habitats are eliminated altogether. Fragmentation causes other problems: reduced total area reduced interior/edge ratio reduced habitat heterogeneity reduced connectivity greater inter-fragment distance unable to migrate with changing climate

9. Smaller fragments support fewer animals. Figure 1

10. *** What is the pattern? What explains it? Figure 2

11. Which size of area is needed? Will a park be Sufficient?

12. Principles for design of nature preserves:If create preserve from large expanse of uniform habitat: larger is better than smaller SLOSS: single large or several small? one large area is better than several small that sum to same size add corridors or ‘stepping stones’ circular is better than elongate with more edge

13. Why are larger areas better? support more species by reducing likelihood of stochastic extinction promote genetic diversity buffer populations against disturbance avoid ‘edge effects’ offer freedom to migrate

14. ***Summarize two major results.Corridors enhance migration between patches and maintain population cohesion. Figure 3

15. ***What are advantages of corridors? Are there disadvantages?

16. If creating preserve out of diverse habitat: Several small in different habitats better than one large in uniform habitat Plan for migration ---> use corridors stepping stones to link habitats bridge roads and pipelines that impede movement

17. Consider community structure Top-down control of trophic abundances Cascade effects: indirect effects extended through multiple levels Can have chain of extinctions if highly dependent Keystone organisms must be preserved Non-redundant species, key species that maintain stability/diversity

18. How does species (and functional) diversity affect community response to disturbance?

19. Population models assume: large size (> minimum viable population size); no variation in average birth and death rates. In reality, randomness affects populations, especially small ones: Catastrophe Variation in environment Stochastic (random sampling) processes Chance events may cause small populations to go extinct. Minimum viable population size = >500

20. Probability of extinction increases over time; increases with smaller initial population size. Small populations are more likely to go extinct due to random fluctuation in population size. Figure 4

21. ***Summarize the two main results. Provide a reason for each result. What traits enable a population to rescue asmall population from extinction? Figure 5

22. Rescue effect: Immigration from a large subpopulation can keep a declining subpopulation from inbreeding and going extinct. Can produce positive density-dependence: survival of subpopulations increases with more subpopulations.

23. Mainland-island model:Sourceprovides emigrants to sink. source sinks Figure 6

24. Sample exam ? You are asked to design a national park system for a tropical country. 1) How will the concept of ‘hot spots’ of diversity influence your choice of areas to conserve? You have defined your locations. What are 4 principles that you will consider in the next phase: their spatial design? What specific attributes of parks are needed to accommodate specific flora or fauna? What general criteria related to preserve size must be met to ensure long-term survival of species? (assume habitat requirements are met)

25. Restoration Ecology • Basic principles of ecology have practical use for solutions to human problems • Use research • to better understand ecological processes within highly disturbed ecosystems • to enhance their complexity and long-term persistence NRES 420 Restoration Ecology

26. Objectives • How blend science into practice • Important ecological principles for restoration • Population • Community • Landscape • Ecosystem • Practice of restoration

27. Illinois in Need of Restoration • Clearly a need – • Remaining habitat: • 0.01% prairie • 9.9% wetland • 31.4% forest • U.S. Rank: • Indiana 48 • Illinois 49 • Iowa 50

28. Which level(s) of ecology are applicable? POPULATION ECOLOGY COMMUNITY ECOLOGY RESTORATION ECOLOGY ECOSYSTEM ECOLOGY LANDSCAPE ECOLOGY

29. Goals:Improve the ecology of a disturbed area by: – increasing diversity in highly disturbed system – reestablishing characteristic species and community structure/function – reintroducing ecosystem function (productivity and nutrient cycling) – may have to start restoration from scratch van Diggelen, Grootjans & Harris (2001)

30. Must apply ecological principles within a social context… POLICY POPULATION ECOLOGY COMMUNITY ECOLOGY ECOLOGICAL RESTORATION SOCIETY ECONOMICS ECOSYSTEM ECOLOGY LANDSCAPE ECOLOGY POLITICS

31. What aspects of Population Ecology are relevant to Restoration Ecology? Species survival depends on maintaining minimum viable population levels (>500). maintaining genetic diversity. using locally adapted genotypes. having a metapopulation structure with strong source subpopulations to rescue sink ones.

32. What aspects of Community Ecology are relevant to Restoration Ecology? • Species-area relationships • Island biogeography theory • Problems with fragmented habitats • Intermediate disturbance hypothesis • Succession & community assembly • Diversity-stability theory; community structure

33. S = c Az log S = log c + z log A How is the Species-Area curve relevant? S = c + z log A Figure 1

34. Immigration Rate (species per year) Extinction Small Large Number of Species Near Far How is Island Biogeography Theoryrelevant? Figure 2

35. Patch relationships: What are 2 take-home messages? Figure 3 (From Forman, 1995)

36. Ecological Disturbance: What are its dimensions? How relate to restoration? 1 2 3 Figure 4 (D.T. Krohne, ‘General Ecology’)

37. Number of Species Competitive exclusion Intermediate Disturbance Hypothesis:at which level does disturbance aidrestoration? Why? Small species pool Disturbance Rate Figure 5

38. Natural Events** Fire Disease epidemic Flood Herbivory Drought Hurricane, tornado, windstorm Avalanche, landslide Volcanic eruption Ice storm Anthropogenic Events** Residential development Road, trail, railroad line Telephone line, electrical power line Dam, water diversion, canal Commercial development Modern agriculture Mining Logging Grazing Selected Natural & Anthropogenic Disturbances: reversible vs. permanent change? ** Entries in italics connote reversible disturbances; others represent long-term or permanent conversion of habitat.

39. Succession • an orderly change in relative abundances of dominant species in a community following a disturbance until a stable community (‘climax’- like predisturbance) results

40. Succession: Species-Species Interactions How do these interactions influence community development? • Facilitation – early species make environment less suitable for themselves, but more suitable for later species -- nurse crops - Tolerance - early species make environment less suitable for recruitment of similar early species, but they neither help nor hinder later species - Inhibition - early species make environment inhospitable to later-arriving species Early prairie reconstructions overly dominated by warm season grasses

41. Community Assembly • development of the ecological community • determined by: • random variation in species' colonization • subsequent species interactions

42. Which orientation to follow?Succession vs. Community Assembly • Succession • Deterministic • Internal interactions & environment determine outcome • Assembly • Stochastic • Supply of propagules determines outcome • Multiple stable assemblies

43. How can succession be managed to aid restoration?

44. Managing Succession Controlled Colonization Controlled Species Performance Restoration: Managing Succession Designed Disturbance

45. Managing Succession: in Practice

46. How can community structure influence stability of restored community? • Top-down control of trophic abundances • Cascade effects: indirect effects extended through multiple levels • Can have chain of extinctions if highly dependent • Keystone organisms must be preserved • Non-redundant species, key species that maintain stability/diversity

47. How can Diversity Complexity Stability be enhanced? • An increase in the structural diversity of vegetation increases species diversity. • Full restoration of native plant communities sustains diverse wildlife populations. • A high diversity of plant species assures a year-round food supply for the greatest diversity of wildlife

48. How does the landscape context of the restoration influence everything discussed earlier? LandscapeEcology

49. Spatial Principles • Large areas sustain more species than small areas. • Many small patches in an area will help sustain regional diversity. • Patch shape is as important as size. • Fragmentation of habitats, communities, and ecosystems reduces diversity. • Isolated patches sustain fewer species than closely associated patches. • Species diversity in patches connected by corridors > than for disconnected patches. • A heterogeneous mosaic of community types sustains more species & is more likely to support rare species than a single homogeneous community. • Ecotones between natural communities support a variety of species from both communities & species specific to the ecotone.

50. Largest patch size • Patch longevity • Disturbance frequency • Habitat requirements Minimum Dynamic Area in Restoration Design