Informational needs for assessing Critical Habitat

1. Todd Hatfield Solander Ecological Informational needs for assessing Critical Habitat Jordan Rosenfeld Aquatic Ecosystem Science Section B.C. Ministry of Water Land and Air Protection

2. Talk Outline 1)General definitions of Critical Habitat 2)Generic approach for assessing Critical Habitat 3)Examples of information needed to determine Critical Habitat

3. Why define critical habitat? Need to PRIOIRITIZE habitat protection for species recovery and management BASIC ASSUMPTION: allhabitats are NOT equally important for species persistence

4. MEGA DAM CORP. Consequences of not credibly defining critical habitat: 1) The wrong habitats may be protected, contributing to species demise 2) Designation of critical habitat will be vulnerable to challenge bystakeholders (especially if there are significant lost opportunity costs ($$) of habitat protection)

5. The PROBLEM is thatunfocusedcollection of information(i.e. research)can take alifetimeand huge resources ($$$) (Usually significant TIME CONSTRAINTS for managing endangered species) The CHALLENGE is tocorrectly identifyandcollecttheminimum informationrequired tocrediblyidentify critical habitat

6. Working Definitions of Critical Habitat (“Screening” criteria) Habitat that is disproportionately importantwhose (cumulative) loss will result in significant population level effects Defn. #1 Minimum subset of habitats required for a species (popn.) to persist(or to achieve specified recovery goal) Defn. #2 Habitats that are necessary to maintain ecosystem function and the processes that create criticalhabitat (e.g. riparian zones) Defn. #3

7. Defining critical habitat is primarily about understanding the role of habitatin population limitation i.e. you need to determine the AMOUNT of habitat require to meet a RECOVERY TARGET

8. Habitat Quality Habitat Area x Simplistically, Population Size (Recovery Target) = PopSize = (Habitat quantity) e.g. 3000 indiv.= 1500 m2 x 2 individuals/m2 3000 indiv.= 500 m2 x 6 individuals/m2

9. N 1 target Abundance 2 3 H crit Habitat area This can be organized as a 3-step process: 1) identify a population recovery target 2) define a quantitative relationship between habitat and population size 3)define sufficient habitat to meet the recovery target based on the habitat-population relationship

10. N 1 target Abundance 2 3 H crit Habitat area This can be organized as a 3-step process: 1) identify a population recovery target 2) define a quantitative relationship between habitat and population size 3)define sufficient habitat to meet the recovery target based on the habitat-population relationship

11. Spawning (egg) habitat Juvenile rearing habitat (summer/winter) Smolt estuarine habitat Adult ocean habitat Defining Critical Habitat by Life-history Stage Critical habitat must be defined for each life-history stage of a species Critical habitat may also vary with season, sex, etc.

12. N eggs target Abundance N juv target N ad target H H H crit crit crit eggs juveniles adults Habitat area For species with multiple life-stages using different habitats: Sufficient individuals must recruit to each life stage to meet the adult recovery target Therefore repeat the process to identify required area of critical habitat for each life-stage

13. Identifying the limiting life-history stage One habitat will often be a limiting bottleneck, so that habitats used by subsequent life stages are unsaturated Adult N . . . . . = 2 . . L UNSATURATED UNSATURATED . . . . . . . . . = 3 . L UNSATURATED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . = 6 . . . . . . . . . . . . . . . . Adult Juvenile rearing Egg (spawning) L

14. SUBSTITUTABILITY of Critical Habitats The substitutability (if any) of habitat can be evaluated based on habitat capacity relative to recovery goals (e.g.from PVA or other criteria) If habitat is limiting the species at or below recovery objectives, then all existing habitat must be protected If habitat is not limiting, then substitutable configurations may protect the required habitat capacity 4 km Habitats may be substitutable in SPACE, TYPE, or EXTENT e.g.

15. a) b) 5 3 4 2 3 1 2 0 1 -1 1 -1 c) d) 5 3 4 2 3 1 2 0 1 -1 2 0 3 1 4 2 5 3 3

16. Informationneeded to determine Critical Habitat 1) Basic life-history information  what habitats are used/required? 2) Which life-history stage is limiting the population? 3) Basic habitat information  what habitats are available?

17. 4) What is quality of available habitat (i.e. how does quality affect abundance)? - quality in terms of fish density growth survival fecundity Need this info. to determine popn. consequences of different critical habitat configurations

18. How to assess habitat quality? i.e. effects of habitat type or characteristics on density, growth, survival, or fecundity?

19. Habitat quality is often inferred based on: presence/absence (occurrence), but density (abundance) is a better index of habitat suitability Density may in some cases be a misleading indicator of HQ, in which case growth, survival,andfecundityare better indicators of the fitness consequences of using different habitats

20. Quality of habitats for different life- stages can be inferred based on: 1) Observational field studies – occurrence or density in different habitats 2) Field or lab experiments – growth and survival in different habitats This information can then be used to paramaterize population models to predict the population effects of different habitat configurations

21. 3) Monitoring/adaptive management following habitat restoration can be used to infer > which habitats are limiting > how quality differs between restored and original habitat

22. 1) Metapopulation considerations  do subpops differ in biological (e.g. genetic/adaptive significance?  do subpops differ in potential contribution to species persistence?

23. Critical Habitat for Salish Sucker Recovery Objectives were to maintain the species throughout its distribution; therefore need to define critical habitat for all populations Mike Pearson

24. Sucker Critical Habitat Description (Proposed) Reaches with more than 50 m of continuous pool with a waterdeeper than 70 cm. Riparian reserve strips; interim guideline width of 5 metres from top of bank. Other habitats may be identified as critical if important for spawning, rearing, migration, etc.

25. 200 150 100 CPUE (fish.trap-1) 50 0 0 50 100 150 200 Depth (cm) Reaches with at least 50 m of deep pool were chosen because this includes all reaches with moderate or high densities of Salish sucker (Pearson thesis)

26. Watershed Area of Deep Pool in Interim Population Recovery Critical Habitat Reaches Target * Agassiz Slough 39,200 2000 Atchelitz/Chilliwack/Semmihault 140,000 7000 Bertrand Creek 16,100 1200** Fishtrap Creek 94,600 4700 Miami Creek 30,000 1500 Mountain Slough 45,500 2300 Pepin Creek 24,000 1200 Upper Salmon River*** 35,800 1800 Salwein Creek/Hopedale Slough 53,900 2700 Recovery targets calculated assuming a density of 0.05 adult/m2 in all deep pool habitats within critical habitat reaches. (This density corresponds to a catch-per-unit-effort of approximately 1 adult/trap (Pearson 2004a))

27. Dace Critical Habitat Description (Proposed) Reaches with more than 10% riffle by length Riparian reserve strips; interim guideline width of 5 metres from top of bank Mike Pearson

28. Dace occur almost exclusively in reaches with > 10% riffle Little information on how density varies within riffles

29. Population estimates for dace (critical habitat area x average density) are ~3000-5000 within proposed critical habitat

30. Benthic Limnetic Todd Hatfield Critical Habitat for Stickleback Species Pairs This is a much more complicated issue

31. in Enos lake the benthic and limnetic sp. have collapsed into a hybrid swarm Critical Habitat for species pairs in NOT about population limitation - proximate cause of endangerment isHYBRIDIZATION Critical Habitat therefore constitutes those habitat features that preserve reproductive isolation (e.g. ensure proper mate recognition)

32. Habitat features that have directeffects on mate recognition: e.g. TURBIDITY Habitat features that have INdirecteffects on mate recognition: e.g. PRODUCTIVITY (prey abundance that affects adult growth) Water Quality and benthic and zooplankton production have to be maintained within appropriate ranges (NEED TO BE DEFINED)

33. Todd Hatfield Populations of benthics and limnetics have to be sufficiently large to prevent hybridization

34. Pelagic Littoral/Benthic Need appropriate proportions of limnetic/littoral habitat - Will be sensitive to water levels!

35. Most of the stickleback species pair lakes are water supplies or otherwise subject to drawdowns So, we have a lot to do in terms of defining critical habitat for species pairs. That being said, critical habitat is not the primary issue for species pair persistence – exotic introductions is a far greater concern

36. National Recovery Team for Freshwater Species at Risk in B.C. Todd Hatfield – Co-ordinator, Solander Ecological Research Dan Sneep – Co-Chair, DFO Vancouver Jordan Rosenfeld – Co-Chair, WLAP UBC Duane Jesson – WLAP, Lower Mainland Region Don McPhail – UBC Zoology John Richardson – UBC Forest Sciences Eric Taylor – UBC Zoology Paul Wood – UBC Forest Resource Management

38. Benthic Limnetic Todd Hatfield 5) Special Cases: Critical habitat may not be related to population limitation e.g. limnetic and benthic stickleback species pairs in Enos Lake - proximate cause of endangerment isHYBRIDIZATION - Critical Habitat therefore constitutes those habitat features that preserve reproductive isolation(i.e. not a population limitation issue)

39. The PROBLEM is that unfocusedcollection of information (i.e. research) to define critical habitat can take a lifetime and huge resources ($$$) (Usually significant TIME CONSTRAINTS for managing endangered species) The CHALLENGE is to correctly identify and collect the minimum information required to credibly identify critical habitat

40. What is critical habitat? Defn. #1 Habitat that is disproportionately importantwhose loss will result in significant population level effects Defn. #2 Minimum subset of habitats required for a species (popn.) to persist(or to achieve specified recovery goals)

41. Spawning (egg) habitat Juvenile rearing habitat (summer/winter) Smolt estuarine habitat Adult ocean habitat Defining Critical Habitat by Life-history Stage Critical habitat must be defined for each life-history stage of a species Critical habitat may also vary with season, sex, etc.

42. RIFFLE POOL POOL Defining Critical Habitat for INDIVIDUALS vs. POPULATIONS POPULATIONS INDIVIDUALS “Habitats required for population persistence (at target abundance)” “Habitats required for growth, survival and reproduction of individuals” Depends on how LOCAL ENV. affects individual performance (growth, survival) Depends on metapop, dispersal and extinction issues; Min. Viable Popn. Size; total EXTENT of habitat available (e.g. # of pools in a stream) e.g. Pools as critical rearing / overwintering habitat for juv. salmonids

43. The extent and quality of critical habitat that will ensure popn. persistence is what you REALLY want to know But this is difficult to assess! Two general approaches: 1)Large scale manipulationsthat affect populations, & measure popn. response ($) e.g. log a watershed (Carnation Ck.) and monitor salmon popn. OR manipulate postulated critical habitat, and monitor popn. response

44. no population level effects 8 year after the study

45. 2) Develop stage-structured HABITAT-EXPLICIT population models based on habitat requirements of individuals - less direct than manipulating populations, but more tractable (time and $) So, understanding critical habitat of both individuals and popns. is important

46. . . . . . . . . . . . . . . . . . EXTENT vs. QUALITY of critical habitat The capacity of a habitat to support individuals will depend both on how LARGE it is and how GOOD it is a SMALL area of GOOD habitat can support a larger popn. than a LARGE area of POOR habitat . . . . . 1 km2 x 5 animals/km2 = 5 animals 0.05 km2 x 200 animals/km2 = 10 animals Extent and quality become important when assessing HOW MUCH habitat is required

47. EXTENT vs. QUALITY as limiting factors One habitat will often be a limiting bottleneck, so that habitats used by subsequent life stages are unsaturated Adult N . . . . . = 2 . . L UNSATURATED UNSATURATED . . . . . . . . . = 3 . L UNSATURATED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . = 6 . . . . . . . . . . . . . . . . Adult Juvenile rearing Egg (spawning) L

48. SUBSTITUTABILITY of Critical Habitats The substitutability (if any) of habitat can be evaluated based on habitat capacity relative to recovery goals (e.g.from PVA or other criteria) If habitat is limiting the species at or below recovery objectives, then all limiting habitat must be protected If habitat is not limiting, then substitutable configurations may protect the required habitat capacity 4 km Habitats may be substitutable in SPACE, TYPE, or EXTENT e.g.

49. Levels of information required for Identifying Critical Habitat 1) Habitat Information – how much is there and of which different types & spatial location Required 2) Organism Information – Increasing Cost Required i) Basic LIFE HISTORY information Increasing Uncertainty (for each life stage) Required ii) PRESENCE/ABSENCE in different habitats (= range at large scales) Preferred iii) DENSITY/ABUNDANCE in different habitats Preferred iv) GROWTH, SURVIVAL, AND FECUNDITY in different habitats Preferred v) Habitat-explicit POPULATION MODEL From March 2003 DFO Critical Habitat Workshop (Jamieson 2003)

50. Scenarios involving different Information Needs 1)Sp. with limited distribution e.g. Hotwater Physa in outlet to Liard Hot Springs (~30m of habitat) At risk because of limited distribution – PRESENCE/ABSENCE info is sufficient to determine critical habitat; density, fitness, population models etc. unnecessary