9. The subcanopy isn’t simply comprised of the offspring of canopy species. Although some of the subcanopy consists of sapling Maples, Oaks, and other canopy species, there are also species that are adapted to growing in the shade beneath the canopy. Among them are Flowering Dogwoods (white flowers) and Redbuds (pink flowers). Notice that the leaves of the canopy trees are just starting to grow. Subcanopy and ground layer plants in the Temperate Deciduous Forests must flower (reproduce) early; before the canopy forms and takes most of the light.
11. The Pawpaw, also called Kentucky Banana, is another subcanopy specialists. All of its relatives live in the tropics. Its fruit is yellow, has the texture of a banana, & is delicious.
12. This is Spicebush, another subcanopy species. The berries are not good to eat but scratching the bark releases a fragrance that is very refreshing and smells like pumpkin pie. The berries are important food for birds and rodents. The four subcanopy species I discussed do not grow large. Dogwoods – about 20 - 25 feet Redbud – about 20 feet Pawpaw –12 to 15 feet Spicebush – 6 to 8 feet
13. Temperate Deciduous Forest ground layer plants are diverse. They flower early in the spring and consequently are referred to as “spring wildflowers”. There is a spectacular show on the forest floor from mid to late March through the beginning of May in southwest Ohio. The following slides show a few of the common spring wildflowers and two local fern species that grow in our Temperate Deciduous Forests. Their early spring reproduction is an adaptation to a short season of warm temperatures & adequate light. Flowering requires a lot of food (photosynthesized sugar) & photosynthesis occurs at temperatures above about 45 o F. The shade created by the canopy will block the light to the forest floor as early as May so wildflowers must reproduce by then.
19. The dominant plants in the Temperate Deciduous Forest are broadleaf, deciduous trees. Temperate zones are those areas where there are four seasons. Broadleaf refers to the leaves being wide, instead of needle-like leaves of Pines. Deciduous leaves are those that fall from the tree in autumn.
20. Deciduous trees drop their leaves as an adaptation to the cold weather of winter. Photosynthesis is driven by light, but the rate at which it occurs is partially dependent on temperature. When the temperature falls to about 45 o F photosynthesis stops. Therefore during winter, leaves wouldn’t be making food, but they would still require it. Trees would have to give up some of the sugar stored in their sap to feed the leaves. It “makes more sense” to drop those leaves than to feed them. They just grow new ones when warm weather returns.
21. People who live in the Temperate Deciduous Forest biome look forward to the colors of the forest each autumn before the leaves drop. Why do the colors change? The chlorophyll molecules that make leaves green are a complex molecule centered around a magnesium atom.
22. Magnesium is in very short supply in the soil. Instead of losing this limited molecule when leaves fall, chlorophyll molecules are broken down by enzymes as the photoperiod grows short. The magnesium from broken chlorophyll molecules is drawn into the twigs and stored for the winter. The following spring, the trees won’t have to absorb this limited molecule, they’ll much of it stored in their twigs.
23. As the chlorophyll disappears, the leaves lose all traces of green color. The remaining pigments (red, yellow, orange) were always there, but there was so much chlorophyll that it overpowered those other colors. When the chlorophyll is gone, the others can be seen.
30. Temperate Deciduous Forest soil is thick and fertile. The warm summer temperatures allow for leaves, twigs, dead animals, etc. to decompose and enrich the soil, but unlike Tropical Rainforests the plants and animals in Temperate Forests aren’t active all year. As a result the nutrients build in the soil during the portion of the year when plants are inactive. In tropical forests the plants, being active all year, absorb the nutrients as soon as they decompose. Consequently, Tropical Rainforest Soil is largely devoid of nutrients. Each autumn leaves drop onto the forest floor and come spring they’re soaked with rain. As the weather warms they decompose to add valuable nutrients to the soil Rich, forest soil is airy and it has a moldy smell to it. The decomposing leaves work like mulch, protecting the soil from drying out. This cycle is very important to maintaining the richness of Temperate Deciduous Forest soil.
31. Animals also must adapt to life in the Temperate Deciduous Forests. Because we live in that biome, we are used to it and think of it as “normal”. In fact, it’s a pretty difficult place to live in some regards. Think about life in the Tropical Rainforests; plenty of water for producers to do their thing and make food for heterotrophs. The annual temperature may fluctuate by only 20 to 25 o F. Those are pretty stable conditions. Organisms living there don’t need to adapt to drought or cold. Now think about life for organisms in southwest Ohio. We get abundant precipitation in the spring, but during the summer it can be incredibly dry. You only need to think back to last summer. In my lifetime, I’ve seen 102 o F and I’ve experienced -24 o F. For those of you who have lived in Ohio all your life, you have seen a year that has fluctuated over 110 o F between summer and winter. Imagine how difficult that is for a bat, bird, frog, or chipmunk.
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33. Many birds, particularly those that don’t eat seeds, have to migrate south to find insects, other small animals, or fruits to eat .
34. Bird migration generally takes place at night. Flocks of millions of birds of mixed species follow fly ways that take them to their wintering grounds. Depending on the species, they are guided by celestial cues or by the Earth’s magnetic fields. Migration occurs at only a few hundred feet off the ground. When birds evolved, there were no human structures such as tall buildings or large antennae reaching to such heights. Today many migratory birds die en route because they crash into antennae and the cables that support them. Because large buildings are in cities, birds can see and avoid them.
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36. Examples of local migratory birds that must leave because their food supply disappears during winter. Robins – insects, worms, fruit Orioles - fruit Swallows - insects Hummingbirds – nectar & spiders Examples of birds that remain because their diet allows them to do so. Canada Geese – seeds & grasses Diving Ducks – fish Dabbling Ducks – seeds, snails, etc. Cardinals – seeds Crows – seeds & anything edible Hawks – rodents & small birds Woodpeckers – insect larvae from under bark Some migratory birds from Canada overwinter in Temperate Deciduous Forests. To them, southwest Ohio might be plenty far south. The Robins you see during winter are Robins from Canada and are adapted to eating seeds.
37. Hibernation is a strategy used by animals that are able to regulate their body temperature for extended periods of time. True hibernators lower lay on fat, then lower their body temperature and metabolic rate so their fat stores will last them through the winter. Many animals will burn off a tremendous amount of weight while hibernating. Rousing hibernating animals is generally dangerous to them. People who explore caves during winter have caused serious declines in bat populations. Bats are so small that they can store just enough fat to get them through the winter. When people with flashlights enter their caves the bats stir and sense the need to fly to escape the danger. However, with their body temperature suppressed, the bats must warm themselves to their normal body temperature in order to fly. To do so, they vibrate their muscles (shiver) until the friction warms them. Two or three episodes of this in a single winter will cause them to burn off so much fat while shivering that there isn’t enough left to last them through the winter. Many bats are federally endangered. To protect them, the U.S. Fish & Wildlife Service has installed iron gates across the mouth of caves or mines in which bats hibernate. Bats can fly in and out, but people can’t get in.
38. Examples of Temperate Deciduous Animals that hibernate…. Black Bears – female actually gives birth while hibernating. Cubs are born & nurse for 2 months while mom is hibernating. Chipmunks Groundhogs Some, but not all mouse species
39. Red Bats (far left) and Hoary Bats (near left) are tree bats. Tree bats are here from late April through October. They migrate south, flying in flocks with birds, for the winter. Indiana Bats stay here all year. They hibernate by clustering together in caves and mines, lowering their body temperature and existing on fat stores until warm weather returns. There are probably 1000 or more in this group. Local bat species use a couple of ways of dealing with the cold.
40. Then there are those animals that use some strategy that allows them to just wait out the cold. Some must actively forage for food, others stockpile it during summer, and still others simply “turn off their body” and freeze until the temperatures warm up again.. Squirrels are rather famous for their behavior of collecting and storing seeds and nuts. This behavior is called caching and the stockpile of food is called a cache .
41. During winter, some mammals add fine hairs to their pelage (fur) that grows so dense that it insulates them from the cold. The Red Fox below (left) has its less dense summer pelage. The winter pelage (right) is obviously thicker. During spring, its winter hairs will fall out in clumps.
42. Mammals that are hibernators are endothermic (“warm blooded). They can maintain their body temperature at a few degrees above freezing. What if you’re an ectothermic animal? For example a snake or a frog? They have no control over their body temperature. If the temperature falls to 34 o F, so does their body temperature. Survival may depend on avoiding freezing temperatures. Snakes must take refuge from the cold by going underground or in shelters where the temperature never falls below freezing. Frogs do one of three things. They burrow straight down into soft soil until they’re below the frost line (below the point where freezing temperatures reach). Or, they may jump into a pond and set on the bottom. As long as the pond doesn’t freeze to the bottom, the temperature at the bottom will be above freezing. Water is amazing, it’s less dense as a solid. Therefore in its solid state it floats, insulating the water below from the cold air above. But some species can’t burrow and they cannot physiologically tolerate submersion in water for more than a few hours (next slide please )
44. Spring Peepers and Wood Frogs overwinter on land under leaves where the temperature may fall below freezing several times during the winter. When the temperature approaches freezing, Wood Frogs have enzymes that convert their glycogen, a starch stored in their liver, into glucose (sugar). The circulatory system carries this sugar to their cells which increases the concentration of solutes (dissolved stuff) in the cytoplasm. If you add solutes to water, it suppresses the freezing point. These cells with their high solute concentration, like a glass of sugar water, do not freeze. However water between the cells, which lacks the glucose will freeze. So much water is frozen in the extracellular spaces (between the cells) that the frog will feel like a block of ice. If you were to throw it at a wall, it would shatter like glass. But because the water in its cells remains unfrozen, the cells are not harmed. If a frozen Spring Peeper or Wood Frog is allowed to thaw slowly, it will regain consciousness in 12 to 24 hours and survive as if nothing happened. This phenomenon is called freeze tolerance .
45. A frozen, but not dead Wood Frog Go to http://www.pbs.org/wgbh/nova/nature/frozen-frogs.html to learn more about Wood Frog freeze tolerance. Jon Costanzo, the scientist in the video, is Dr. Lee’s research partner (Dr. Lee talked to you about Antarctica). Lee and Costanzo are responsible for unfolding the details of freeze tolerance in Wood Frogs.
46. Remember these guys? Goldenrod Gallfly larvae are freeze tolerant, but they use a different antifreeze agent, called glycerol, in their cells. It’s the stuff we pour in our cars’ radiators.
47. The Temperate Deciduous Forest has rich biodiversity. Obviously it isn’t as rich as that of Tropical Forests, but because it is surrounded by several other biomes, the Temperate Deciduous Forests shares the flora and fauna of the Grasslands and Coniferous Forests where it adjoins them. Northern species from the Coniferous Forest extend into the northern limits of the Deciduous Forests and western species from the Grasslands extend east into the fringes of the Temperate Deciduous Forest. Because Temperate Deciduous Forests are well shaded, the forest floor tends to hold moisture and consequently it has a good diversity of amphibians, especially salamanders. Ohio has 25 species. The greatest salamander diversity in the world is in the Appalachian Mountains in eastern Tennessee and western North Carolina. The following slides show just a few of Ohio’s salamanders, all of which can be found in Hamilton County.
49. The Ringneck Snake is a 14 inch long Temperate Deciduous Forest species that specializes in feeding on salamanders.
50. Temperate Deciduous Forests have squirrels adapted to life in trees. While you might question why this is worth mentioning, remember you live in the Temperate Deciduous Forest biome so you’re used to tree squirrels. In the Grasslands and Desert, squirrels are burrowing animals. This biome has other rodents as well. There are many species of mice and rats. There are mammals that prey on those rodents. Bobcats, two species of foxes, and numerous weasel species are Deciduous Forest residents. Reptiles are also abundant. Snakes, lizards, and the Eastern Box Turtle are all here and adapted to life in the Temperate Deciduous Forest.
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61. Gross Primary Productivity vs. Net Primary Productivity GPP – total amount of energy converted to plant tissue. Net Primary Productivity – GPP minus what is used by the producers. NPP is what is left over for the consumers.
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70. Gross Primary Productivity vs. Net Primary Productivity GPP – total amount of energy converted to plant tissue. Net Primary Productivity – GPP minus what is used by the producers. NPP is what is left over for the consumers.
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72. Gross Primary Productivity vs. Net Primary Productivity GPP – total amount of energy converted to plant tissue. Net Primary Productivity – GPP minus what is used by the producers. NPP is what is left over for the consumers.
73. Gross Primary Productivity vs. Net Primary Productivity GPP – total amount of energy converted to plant tissue. Net Primary Productivity – GPP minus what is used by the producers. NPP is what is left over for the consumers.
74. Gross Primary Productivity vs. Net Primary Productivity GPP – total amount of energy converted to plant tissue. Net Primary Productivity – GPP minus what is used by the producers. NPP is what is left over for the consumers.
