1. Coastal ecosystems: marshes and mangroves Not strictly “biomes” Position at land-sea interface creates gradational environment and communities Character strongly determined by variations in substrate Common management and jurisdictional problems

2. Variations in coastal substrate: stability, droughtiness, fertility, aeration and salinity marsh/mudflat beach gravel dune sand

3. Classification of coastal ecosystems Tidal Regime Substrate intertidalsupratidal Rockrockweedcliff Gravelabioticshingle Sandabioticdune Mudmarsh, swamp forest mangrove* Bioticreef*atoll *tropical

4. Distribution of salt marshes and mangroves, North America “active” coast “passive” coast

5. Diversity of salt marsh plant communities, North America 78 spp 347 spp. 28 spp

6. Coastal geomorphology and the distribution of marsh and mangrove communities Active coastPassive coast delta - estuary barrier-beach lagoon marsh-mangrove uplandbarrier-beach

8. The Fraser River delta as a type example of Pacific coast marshes Boundary Bay Lulu I.

9. Variations in seasonal river discharge and sediment load (Puget Trough) Seattle Vancouver

11. Marsh communities display strong zonation with elevation Low brackish marsh High brackish marsh

12. Vertical zonation on the Lulu Island foreshore Low marsh High marsh Middle marsh Plant species abundance Duration of flooding % exposure (Hutchinson 1982, CJB) Tide flats

13. Flooding regime and salinity interactions on marsh development 0 36 SALINITY (g/l) Elevation MLW MTL ExHW Tideflats low marsh MHW mid marsh high marsh Boundary Bay Lulu Is. var ns in flooding tolerance var ns in salinity tolerance

14. Colonizing the mudflat: clonal growth of Scirpus spp. on the Lulu Island foreshore

15. Root morphologies of marsh plants “guerilla” morphology “turf” morphology

16. Root and rhizome morphology in a local marsh plant Carex lyngbyei 10 cm Rhizomatous shoot rhizome Shoot from root collar

17. The low marsh environment: adaptations to daily inundation and anoxic substrates High [O 2 ] (source) Low or no [O 2 ] (sink) flooding tide Passive diffusion of oxygen down stem and through root via aerenchyma maintains root respiration; diffusion out into soil oxidizes and precipiates iron sulphides, etc. (potential toxins) in the rhizosphere.

18. Aerenchyma in stem and root of Distichlis spicata (saltgrass) Stem (x48)Root (x48) Aerenchyma (produced by lysis of living cells)

19. Marsh aggradation: from low to high marsh Stems filter out sediment in suspension in tidal waters Benthic microorganisms (esp. diatoms and cyanobacteria) stabilize the mud

20. harsh environment benign environment weak competition? strong competition? Low brackish marsh High brackish marsh

21. A competitive model to explain marsh zonation MTLExHWMHW Growth in the absence of competition Field distribution competitive refuge

22. Vertical zonation in Atlantic and Gulf Coast marshes

23. Competition in a bare patch in a high marsh environment [guerilla roots] [turf roots] annual

24. High marsh colonization sequence YEAR 0 Bare spot: high evaporation results in hyper- salinity YEAR 1, 2 Invasion by salt-tolerant spikegrass and glasswort: plant cover reduces evaporation rate, salinity lowered YEAR 3, 4 Immigration and domination by less salt- tolerant, but highly competitive (turf roots) black rush.

25. Dealing with high salinities e.g. Batis maritima growing in hypersaline (80-100 g/l) lagoonal soils in Sinaloa, Mexico

26. Salt marsh halophytes Batis maritima Succulent plants: 1. have a higher inherent salt tolerance than glycophytes 2. avoid high salt concentrations by increasing cell water content. 3. shed plant parts once salt concentration reaches toxic levels. Salicornia virginica Other strategies: Salt excretion via specialized salt glands on leaves [e.g. Distichlis spicata]. Succulents do not possess salt glands

27. High productivity: where does it go? winterspring summer fall PNW marshes: 400-2800 g m -2 a -1

28. A coastal marsh food web

29. Lesser snowgeese grazing on young shoots of Carex lyngbyei

30. Lesser snowgeese (Chen caerulescens) grubbing for bulrush rhizomes in the Fraser delta marshes

31. Snowgoose grub hole

32. Trumpeter swan (Olor buccinator) grub hole 10 cm

33. A biotically-cratered marsh landscape

34. Changing marsh communities: invasion of exotics (e.g. Spartina alterniflora into Washington State)

35. Mangrove ecosystems

36. Mangrove distribution (55 spp in 11 plant families)

37. Bruguiera spp.

38. Rhizophora (red mangrove)

39. Avicennia (grey & black mangrove)

40. Mangroves: vertical zonation HTL Rhizophora Avicennia Brugueira/Xylocarpus Lagunculuaria Successional sequence Salt pan?

41. Mangroves: species – salinity relations Data: Gulf of Fonseca, Honduras; [ Source: mitchnts1.cr.usgs.gov/ projects/intmangrove.html]

42. Red mangrove stilt roots

43. Grey and black mangroves: pneumatophores (and mangrove aerenchyma)

44. Mangrove lenticels (breathing pores) O2O2 Photo credit: Newfound Harbor Marine Institute

45. Other adaptations: salt glands (on leaves and roots) and vivipary (Rhizophora seedlings can float and remain viable for a year) Salt glands on Conocarp us leaf Rhizophora seedlings: a) on parent plant; b) in mud

46. Salt pans: e.g. Avicennia subshrub in hypersaline soil, Sinaloa, Mexico

47. Crocodilians as geomorphic agents in mangroves Alligators and saltwater crocodiles keep upper reaches of tidal channels open, thereby increasing ebb flows, and slowing invasion by late successional species such as Conocarpus

48. Mangrove crabs Crabs are often considered the keystone species in mangrove ecossytems. They shred and eat leaf litter, making smaller particles available for bacterial and fungal colonization. Their faeces provide a direct nutrient source in the forest, and larval crabs are prey for many small fish. Their burrowing activities aerate the anoxic soils. Images: www.sfrc.ufl.edu; www.kingsnake.com

49. Mangrove distribution World 1980 (‘000 km 2 ) 1990 (‘000 km 2 ) 2000 (‘000 km 2 ) Annual change 1980-90 (%) Annual change 1990-00 (%) 198.1163.6146.5-1.9-1.1 Data and chart: FAO

50. Mangrove deforestation Causes: conversion to fish and rice farms; logging for fuelwood and charcoal Effects: loss of subsidy to neighbouring neritic ecosystems; loss of nursery function; reduction in protection of coastal settlements (e.g. typhoons, tsunamis, etc.)

51. Mangrove –– shrimp farm conversion above: coastal shrimp farms and mangrove remnants on the Pacific coast of Honduras, 1997; below: the same area in 1987 (one shrimp farm in NW quadrant). Images: wikipedia

52. Mangrove primary production 700 - 2000 g m -2 a -1 production ~90% leaves (salt removal) Very little herbivore activity Most production is exported by tides or consumed in detrital food chain

53. Mangrove nurseries “The submerged roots of mangroves provide protection and habitat diversity and their leaves start the food web. Mangrove leaves that fall into the water feed fungi, bacteria, and protozoa that in turn feed invertebrates, and they in turn feed juvenile fish. Of course the small fish attract larger picivorous fish like barracuda.” Wildlife of Mangrove ecosystems www.sfrc.ufl.edu Images: www.pcebase.org; www.sfrc.ufl.edu

54. Mangrove forests and coastal protection Wanduruppa, set within degraded mangrove forests, was severely affected by the Indian Ocean tsunami: 5,000 to 6,000 people died. Nearby Kapuhenwala, surrounded by 200 hectares of dense forest, lost only two villagers – the lowest death toll of any village in the country. Source: IUCN Banda Aceh coast, post-tsunami Mangrove nursery, Thailand Restoration of coastal forests for tsunami/storm surge protection is now widespread in SE Asia, although the efficacy of “tsunami forests” is much debated