1 School of Sciences, Lautoka Campus BIO509 Lecture 35: Plants and Environment – Biomes

2 Plants and animals live together in many different environments all around the world.Organism and environmental interactions determine whether or not an individual member of a species can survive and reproduce in a particular habitat. Environment of each habitat is determined by living (biotic) and nonliving (abiotic) factors.

3 Present Distributions of PlantsVegetation present in a particular location is the result of complex factors. Climate and continental drift are probably the most important. Because flowering plants are presently the most abundant & diverse, they are the best group to use for explaining the current plant distribution.

4 The Role of Geological ProcessesContinental Drift Soil

5 When angiosperms evolved (cWhen angiosperms evolved (c. 140 mya), the 2 supercontinents (Gondwana & Laurasia) where close enough to allow cross dispersal. When Gondwana & Laurasia drifted apart two separate floras (northern & southern) began to form. Further breaking apart of continents resulted in more divisions of flora (independent evolution)

6 What about the South Pacific?Most present islands in the Pacific are geologically young (40my or less). The oldest are the result of the collision of the Australian and Pacific plates. That means that most, if not all, flora must have arrived on these islands by dispersal.

7 Soil Plants compete for nutrients (nitrogen, phosphorus, potassium and others) Infertile soils have less nutrients and hence plants struggle Heavy metals (e.g. nickel) are detrimental to plants and only the adapted or tolerant species can survive

8 The Role of Climate Temperature and precipitation are key factors determining what plants can survive. Water is needed for cellular processes. Water freezes at zero degrees. Vegetation can be classified based on mean annual temperature and precipitation. >> Holdridge’s Life Zone System

9 Temperature Precipitation

10 Similar climates produce similar ecosystems where plants have similar adaptationsE.g. succulents Euphorbia sp. (Euphorbiaceae) from Madagascar Lophocoreu schottii (Cacyaceae) from Mexico

11 Plants are not randomly distributed, but only grow where environmental conditions are suitable for them. Plants with similar environmental needs tend to occur together in associations called plant communities, e.g., littoral forest, cloud forest. Biotic or plant communities considered on a global or at least continental scale are called biomes.

12 Vegetation of the world can be divided up in various ways, but a common method is to recognize seven major biomes: Tundra Taiga Temperate deciduous forest Grassland (Savannahs) Mediterranean scrub Desert Tropical rain forest These are on the global level, and include smaller units, e.g., tropical rainforest can be divided into lowland, montane, etc.

13 Tundra Temperate and Boreal Forests Desert Grassland Rainforest

14

15 World Biomes

16 Tundra Harshest biome on earth About 20% of the earth’s land surface Limited extent in Southern Hemisphere (restricted to Antarctica/ Subantarctic islands)

17 There are two kinds of tundra, arctic and alpineArctic is geographical, alpine is topographical. Alpine tundra (named after the Alps in Europe) is found in patches usually at an altitude of about 10,000 feet or more. Average temperature decreases 1°C for every 100 m elevation

18 Tundra – Environmental ConditionsGrowing conditions are extremely limiting Layer from 10 to 100 cm deep is permanently frozen (permafrost) Determines the depth to which roots can grow Nutrient level low in arctic soils

19 Plants must be adapted to:High winds Low temperatures Lack of available moisture Rainfall often averages less than 20 cm a year High winds increase transpiration (drying out) Abrasion by windblown ices and particles. Temperatures freezing most of the year (to 27° C in summer) Short growing season of 2 to 3 months. Able to photosynthesize 24 hours a day in some places during summer (rapid growth).

20 Tundra – Vegetation Dominated by dwarf shrubs, sedges, grasses, lichens and mosses. Basically treeless, but some trees in the form of shrubs do occur (e.g., up to 50 cm high). 98% of tundra plants are perennials, due to short growing season 50% of their biomass is below ground.

21 Tundra – Plant AdaptationsSeasonal reproduction: blooms of showy wildflowers during the growing season Food reserves for rapid spring growth stored during the brief summer

22 Many plants have dark pigments such as anthocyanin – raises temperature of plantSome hairy to reduce heat loss at night Some form dense cushions that retard wind speed inside the cushion, reducing water loss

23 Adaptations needed in pollination (few insects)Wind pollination common (e.g., grasses). Vegetative reproduction is common. Many plants capable of self-pollination.

24 Tundra – Animals Some large mammals No amphibians or reptiles (too cold).

25 Tundra in the Southern Hemisphere (SH) SH has a much smaller land mass Alpine tundra is found in New Zealand, the Andes. Only small amount of tundra in Antarctica (mostly covered with snow and ice).. NZ PNG

26 Taiga Russian word for wet forest. Broad band of coniferous forest or boreal forest Intergrades with tundra on its northern boundary at timberline N America & Eurasia only (not found in Southern Hemisphere)

27 Can also be found in corresponding topographic zone: montane coniferous forest of western North America (Rocky Mountains & Sierra Mountains) and in Europe (Alps). Zonation of dominant species is by elevation. Timberline also found on mountains.

28 Taiga – Environmental Conditions Growing conditions are severe (better than tundra) Short growing season Long, severe winter (snow blanket) Low temperatures (to -50 °C) Low rainfall (between 25 & 100 cm a year)

29 Dominated by evergreen conifers Taiga – Vegetation Dominated by evergreen conifers Few annuals, mostly perennials & a few shrubs Plant diversity is low compared to other biomes Sometimes mono-dominant communities Taiga forest often has four layers: Canopy of coniferous trees Shrub layers of species Herb layer Surface layer (mosses - wet, lichens - dry)

30 Taiga – Plant Adaptations Snowfall: Shortage of water:Conifer habit is conical with drooping branches Shortage of water: Dormancy in winter (reduce respiration) Thick cuticles, sunken stomata, tough epidermis Shallow roots (absorb moisture as soon as available) Fire: Thick barks Cones that open only after fire Shortage of insect pollinators: Wind pollination

31 Taiga – Animals Some large mammals No amphibians or reptiles (too cold)

32 Temperate Rainforest – a Special Type of Taiga Found on northern Pacific coast of America Climate moderated by the effects of nearby ocean (relatively mild winters) Dominated by redwoods & Douglas fir Often high precipitation results in profusion of mosses NZ PNG

33 Temperate Deciduous ForestMost occur on Northern Hemisphere (N America, Europe, E Asia). Also: New Zealand, Chile, East coast of Australia

34 Change of seasons is most significant feature

35 Temperate Deciduous Forest – Environmental ConditionsModerate climate, but major seasonality Temperatures: - 5° C in winter to 25° C in summer Precipitation between 50 and 165 cm a year

36 Temperate Deciduous Forest – Vegetation Dominated by deciduous broadleaves Higher diversity (not mono-dominant) Often has five layers: Canopy Subcanopy of trees shrub layer Herb layer dominated by broadleaf perennials Surface layer of mosses

37 Temperate Deciduous Forest – Plant Adaptations Seasonality:Broadleaf trees are deciduous (compensates for restriction of water in winter) Rapid growth when leaves are regained Conifers are adapted to harsh winters Scarcity of insects wind pollination Changing light regime below canopy Forest floor has sunlight during winter & spring Herbaceous plants grow quick & may become dormant once canopy closes Annuals

38 Temperate Deciduous Forest – AnimalsLarge mammals (except dear and bear) are uncommon

39 Temperate Deciduous Forest – SummaryDominated by deciduous broadleaf trees. Moderate climate (compared to more northern biomes) with great seasonality. Relatively high rainfall. Main adaptation of plants is deciduous character (leaves are lost in autumn to reduce water loss). Biodiversity is much higher than in taiga. Limited in amount in the southern Hemisphere. Herbs do much of their growing in the spring before canopy shades the forest floor.

40 The Grassland Biomes

41 Grasslands are characterized as lands dominated by grasses rather than large shrubs or trees.There are two main divisions of grasslands: (1) tropical grasslands, called savannahs, and (2) temperate grasslands

42 Savannahs (grass lands) are always found in warm or hot climates where the annual rainfall is from about 50.8 to 127 cm (20-50 inches) per year. It is crucial that the rainfall is concentrated in six or eight months of the year, followed by a long period of drought when fires can occur. If the rain were well distributed throughout the year, many such areas would become tropical forest.

43 Temperate grasslands are characterized as having grasses as the dominant vegetation. Trees and large shrubs are absent. Temperatures vary more from summer to winter, and the amount of rainfall is less in temperate grasslands than in savannas. Temperate grasslands have hot summers and cold winters. Rainfall is moderate. The amount of annual rainfall influences the height of grassland vegetation, with taller grasses in wetter regions.

44 Mediterranean forests, woodlands, and scrub

45 Mediterranean forests, woodlands, and scrub biome, as defined by the World Wildlife Fund, is generally characterized by dry summers and rainy winters. Summers are typically hot in low-lying inland locations but can be cool near colder seas. Winters are typically mild to cool in low-lying locations but can be cold in inland and higher locations. All these eco-regions are highly distinctive, collectively harbouring 10% of the Earth's plant species.

46 The Mediterranean forests, woodlands, and scrub biome mostly occurs in, but not limited to, the Mediterranean climate zones, in the mid-latitudes

47 Vegetation type range from forests to woodlands, savannahs, shrublands, and grasslands; "mosaic habitat" landscapes are common, where differing vegetation types are interleaved with one another in complex patterns created by variations in soil, topography, exposure to wind and sun, and fire history.

48 Much of the woody vegetation in Mediterranean-climate regions is sclerophyll, which means 'hard-leaved' in Greek. Sclerophyll vegetation generally has small, dark leaves covered with a waxy outer layer to retain moisture in the dry summer months.

49 Animals Cactus Wren Genus: Campylorhynchus Species: brunneicapilluGolden Jackal Genus: Canis Species: aureus Black-tailed Jackrabbit Genus: Lepus Species: californicus Aardwolf Genus: Proteles Species: cristatus Puma Common Names: cougar, mountain lion, catamount, panther Genus: Puma Species: concolor Animals

50 The desert Biomes

51 Deserts cover about one fifth of the Earth’s surface and occur where rainfall is less than 50 cm/year. Although most deserts, such as the Sahara of North Africa and the deserts of the south-western U.S., Mexico, and Australia, occur at low latitudes, another kind of desert, cold deserts, occur in the basin and range area of Utah and Nevada and in parts of western Asia.

52 Disturbances are common in the form of occasional fires or cold weather, and sudden, infrequent, but intense rains that cause flooding Hot and Dry Desert The four major North American deserts of this type are the Chihuahuan, Sonoran, Mojave and Great Basin. Others outside the U.S. include the Southern Asian realm, Neotropical (South and Central America), Ethiopian (Africa) and Australian.

53 Barrel Cactus Common Name(s): Barrel Cactus, Compass Cactus Genus: Ferocactus Species: wislizeniCrimson Hedgehog Cactus Common Names: Hedgehog Cactus, Claret Cup Cactus, King's Cup Cactus, Mound Cactus Genus: Echinocereus Species: triglochidiatus Parts Used: pulp, flowers and stems Saguaro Cactus Genus: Carnegiea Species: gigante Jumping Cholla Common Names: Teddybear Cholla, Silver Cholla, Cholla Guera Genus: Opuntia Species: bigelovii

54 Coyote Common Names: Coyote Genus: Canis Species: latransArmadillo Lizard Genus: Cordylus Species: cataphractus Desert Kangaroo Rat Common Names: Kangaroo rat, Desert Rat Genus: Dipodomys Species: deserti Javelina Common Names: Collared Peccary, Musk Hog, Tayaussa Genus: Tayassu Species: tajacu Sonoran Pronghorn Antelope Common Names:  Genus: Antilocarta Species: americana sonoriensis

55 Aquatic Biomes

56 Water is the common link among the five biomes and it makes up the largest part of the biosphere, covering nearly 75% of the Earth’s surface. Aquatic regions house numerous species of plants and animals, both large and small. In fact, this is where life began billions of years ago when amino acids first started to come together.

57 The aquatic biome can be broken down into two basic regions, freshwater (i.e, ponds, lakes and rivers) and marine (i.e, oceans and estuaries). The topmost zone near the shore of a lake or pond is the littoral zone. This zone is the warmest since it is shallow and can absorb more of the Sun’s heat. It sustains a fairly diverse community, which can include several species of algae (like diatoms), rooted and floating aquatic plants, grazing snails, clams, insects, crustaceans, fishes, and amphibians.

58 Fresh water Animals Some Marine animals TIGER SALAMANDER

59 Wetlands are areas of standing water that support aquatic plantsWetlands are areas of standing water that support aquatic plants. Marshes, swamps, and bogs are all considered wetlands. Plant species adapted to the very moist and humid conditions are called hydrophytes. These include pond lilies, cattails, sedges, tamarack, and black spruce. Marsh flora also include such species as cypress and gum.

60 Forest Biome: Present-day forest biomes, biological communities that are dominated by trees and other woody vegetation (Spurr and Barnes), can be classified according to numerous characteristics, with seasonality being the most widely used.

61 Distinct forest types also occur within each of these broad groupsDistinct forest types also occur within each of these broad groups. There are three major types of forests, classed according to latitude: Tropical: Tropical forests are characterized by the greatest diversity of species. They occur near the equator, within the area bounded by latitudes 23.5 degrees N and 23.5 degrees S. One of the major characteristics of tropical forests is their distinct seasonality: winter is absent, and only two seasons are present (rainy and dry). The length of daylight is 12 hours and varies little.

62 Temperature is on average 20-25° C and varies little throughout the year:Precipitation is evenly distributed throughout the year, with annual rainfall exceeding 2000 mm. Soil is nutrient-poor and acidic. Decomposition is rapid and soils are subject to heavy leaching. Flora is highly diverse: one square kilometre may contain as many as 100 different tree species. Plants such as orchids, bromeliads, vines (lianas), ferns, mosses, and palms are present in tropical forests. Fauna include numerous birds, bats, small mammals, and insects.

63 Some animals of forests biomesDawn Bat Common Names: Lesser Dawn Bat, Dobson's Long-Tongued Fruit Bat, Cave Fruit Bat, Cave-dwelling Blossom Bat Genus: Eonycteris Species: spelaea African Forest Elephant Common Names: Pygmy Elephant Genus: Loxodonta Species: cyclotis Kinkajou Genus: Potos Species: flavus Harpy Eagle Common Names: Aguila Harpía, Harpía Genus: Harpia Species: harpyja Orangutan Genus: Pongo Species: pygmaeu Some animals of forests biomes

64 Temperate forests occur in eastern North America, north-eastern Asia, and western and central Europe. Moderate climate and a growing season of days during 4-6 frost-free months distinguish temperate forests. Temperature varies from -30° C to 30° C. Precipitation ( cm) is distributed evenly throughout the year.

65 Soil is fertile, enriched with decaying litterSoil is fertile, enriched with decaying litter. understory vegetation and stratification of animals. Flora include tees species such as oak, hickory, beech, hemlock, maple, basswood, cottonwood etc. Fauna is represented by squirrels, rabbits, skunks, birds, deer, mountain lion, bobcat, timber wolf, fox, and black bear. Boreal forests (taiga): has already been described

66 Questions??