ENVIR ST 260 1st Edition Lecture 16 Outline of Last Lecture I Definitions II Grazers III Carbon Cycle IV Group Work Conclusions Outline of Current Lecture I Misconception from Grassland Worksheet II Lecture Activities E Writing III Woodlands and Forests Current Lecture Misconceptions from Grassland Worksheet Climate Most people were in the right ballpark however when we re looking for answers about climate we re looking for temperature and precipitation We should provide numbers for average high and low temperatures as well as annual rainfall Saying that the climate is temperate with moderate rainfall is too vague Grazing Animals A lot of people listed animals that weren t grazers In just about every modern day grassland or savanna ecosystem cows are the main grazers due to the huge beef industry This goes in contrast to the natural grazing animals such as bison antelopes and zebra We should realize that cattle operations behave very differently than natural grazers Cows tend to herd up and stay in the same place so they can really deplete an area of resources On the other hand the natural grazers roam around so their impact is less A high concentration of cattle in one area acts to compact the soil and their waste is different from natural grazers since they re domesticated This all affects the microbial community It s something to think about how we as humans are modifying grasslands Carbon Storage Belowground It s really stored below ground in roots and soils in grasslands These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Charcoal Because fire is common in grassland and savanna ecosystems a lot of carbon gets locked into charcoal Grasslands are a great way to store carbon There s a lot of evidence coming out now that grasslands are a carbon sink which makes them of greater interest for conservation However since they haven t always been a focus of conservation it s difficult to shift the attention to them Conservation and Restoration Focus on other ecosystems The idea of allocating conservation dollars People are often more interested in protecting other areas Applying fire is difficult A lot of systems are fire dependent but it s really difficult to set fires Invasive grasses and trees When you re dealing with large landscapes finding invasive grasses in a sea of grass is really difficult Herbicide treatments are hard to do because they could kill everything Conversion for agriculture A lot of times they make great places to plant crops It s really hard to say we should keep an area for biodiversity and not convert it to agriculture If there s been agriculture on a site it creates problems for restoration because it s difficult to get your native plants to grow in the crop fields Lecture Activities E Writing Lecture Activities Class poll about lecture activities says that most people would prefer 50 minutes of straight lecture Her rational on having us do lecture activities A study compared straight up lectures with lectures combined with active learning Active learning is broad and covers things such as group problem solving worksheets and personal response systems In a straight up lecture you get about 35 failure rate but when combined with active learning components that rate gets pushed closer to 20 It s been shown over and over again that it s beneficial to do active learning E Writing Assignments Final product due December 2 2014 Rubric and format details will be posted soon Start making edits based on feedback from peer review Don t wait till you get the sheet back from her Rubrics back and grades posted next week Woodlands and Forests Major difference between these and grassland ecosystems is tree density General Characteristics of Woodlands and Forests Both are tree dominated ecosystems Difference between a woodland and a forest is canopy cover Woodlands have less densely packed trees Forests have high tree density little light reaches the ground One way to think about this is how much light can reach the ground In woodlands there are more grasses and forbs because light can get through In forests there s a canopy that blocks sunlight and limits the amount of life that can grow on the ground so you don t have a big grass component Forest ecosystems are highly variable There are temperate forests tropical forests and coniferous forests They re all forests but they all have different species nutrient cycles and structures Tropical Rainforest Rainfall and average temperatures are going to be different from your temperate forest as well as the soil and nutrient cycles Tropical plants include big palms instead of just trees Boreal forest These include coniferous forests up in Canada and northern Russia They re typically pine dominated They see a lot of precipitation in the form of snow with cooler temperatures These are ecosystems with very long fire return intervals Therefore they grow for hundreds of years until a fire will come through and wipe them out infrequent disturbances but high tree density Do trees planted in neat rows constitute a forest or woodland Majority of students believed it would be a woodland or forest People that said no This is a just a tree farm with the same type of tree equivalent to a cornfield The lack of species diversity is one thing that s a problem The other would be that once we set things up in a linear fashion we really alter how light filters down to the ground which influences whether or not other species are going to be present you don t get a lot of wildlife The single input of pine needles on the ground changes the microbial communities Just because there are trees does not mean that there is a forest If you see something like this on the landscape linear lines of trees it s not natural Having an even aged group of trees that grow up together isn t necessarily a problem Sometimes a fire will come through natural ecosystems that burns down adult trees allowing seedlings top pop up that are all the same age An even age strand is not a problem An even aged strand planted in rows is Planting things in neat rows make you lose the proper structure Importance of Structure You ll end up with 4 layers Emergent Layer tallest trees Canopy layer where you get the interception of light Most leaves are at this level Understory layer these are trees waiting for an opportunity to get into the canopy Forest Floor tropical systems may have more