E179 MIDTERM EXAM QUESTIONS WITH CORRECT ANSWERS LATEST UPDATE 2026

E179 MIDTERM EXAM QUESTIONS WITH CORRECT ANSWERS LATEST UPDATE 2026 Three general characteristics of Wetlands - Answers 1) They are wet at some point during the year. 2) They have hydric soils 3) They support hydrophytic vegetation Hydric Soils - Answers Soils formed by water/alluvial processes that are different from the soils of adjacent upland habitat. Hydric soils become anoxic when they are wet. Anoxic - Answers Do not have oxygen available to plants or invertebrates Hydrophytic Vegetation - Answers Vegetation that is facultatively or obligately associated with wetland conditions (e.g. cattails, bulrushes). Such vascular plant species are known as "wetland indicator species" Delineate a wetland... - Answers (1) test the soil to find out if it is hydric (2) identify the plants to determine if they are wetland indicator species (3) ascertain if the site is wet at least once a year. How many acres of wetland habitat was there before European occupation? - Answers 200 million How much many acres of wetlands was left by 1970? - Answers Only about 99 million What percentage of wetland was converted by 1970's? - Answers 54% converted to other habitats or developed. Who is the leader of loss of wetland habitat? - Answers California Facts on California wetland habitat - Answers 91% of our wetlands have been sacrificed (5 million acres existed in the 1780s; 454,000 in the 1980s) 97% of our floodplain riparian habitats are lost. Examples of great wetland losses in CA - Answers Sacramento Valley is one of the greatest losses with only 1.5% of the pre-development gallery riparian forest surviving (800,000 acres in 1850 compared to 12,000 in 1972) Mono Lake is diverted for human use causing it to become drier and more basic. Issues in refilling Mono Lake - Answers Mitigation by returning freshwater flow into the lake has been problematic. The water column is separated into two bands, differing dramatically in salinity. This is predicted to turnover within fifty years and will likely kill most of its living inhabitants (notably the brine shrimp Artemia monica). After the turnover and mixing of the dense, highly basic deep waters with the freshwater on top, the lake will be recolonized by brine shrimp. Major Causes of Wetland Habitat Loss - Answers 1) Agriculture 2) Urban development 3) Other Development - dams, stream diversion, and so forth. 5 % was due to these "other" developments Agriculture - Answers By far the greatest cause—nationwide roughly 87% of the loss was due to agriculture. Urban Development - Answers Historically it is estimated that 8 % of the loss was due to urban development. Present Bush - Answers President Bush's (the first Bush) administration fostered the idea of "no net loss" paving the way for mitigation -- the replacement of anthropogenic habitat losses with artificially constructed wetland habitats by converting upland to new, human-made wetland. Bush Mitigation/Conservation - Answers • Legal exchange of destroying a habitat but replacing it somewhere else • For each acre of wetland destroyed, three or more new acres must be created. For some very rare habitats such as vernal pools, a ratio of 10 created to 1 destroyed has been required. • More acres must be created than those destroyed because they are apt to be of lesser quality than the original natural habitat. • If the UC tenth campus is constructed near Merced, that ratio of replacement will be required for vernal pools taken to build the University. Compensatory mitigation - Answers Creation of habitat to compensate for habitat that was legally taken Compensatory mitigation is required and regulated by 2 primary agencies: - Answers 1. At the federal level (Department of Interior): The US Fish and Wildlife Service 2. At the state level: California Department of Fish and Game Do artificially created wetlands resemble true wetlands and perform the same functions for both humans and wildlife? - Answers No. They don't contain comparable species diversity nor are they as productive Wetland Productivity - Answers Wetlands have high productivity, measured as grams of carbon fixed per square meter per year. Productivity in Salt marshes vs. Freshwater wetlands - Answers High productivity is one of freshwater wetlands most significant characteristics. Salt marshes and freshwater wetlands have equal or more productivity than tropical rainforests How many major drainages are in the US? - Answers 11 How many primary drainages are in CA? - Answers 8 Klamath Lahontan North/Central Drainages Death Valley Colorado River Salton Sea South Coastal Sacramento/San Joaquin Where do the drainages drain to? - Answers Some of these drainages extend to the ocean. Interior basin no longer have continuous outflow (e.g., Death Valley) Classification of Wetlands - Answers 1) Their fish fauna (an archaic method historically used by Fish and Game) 2) Type of bottom 3) Vegetation type/community 4) By periods of flooding and inundation, determining the vegetation along the gradient from wetland to upland. 5) Type of Wetland 6) Flow and nutrient quality of the water 7) Zonation Flow and nutrient quality of the water - Answers • Lotic aquatic systems • Lentic habitats • Eutrophic water • Oligotrophic water Two Types of Wetlands - Answers Wetlands watered by groundwater (by a subterranean aquifer) are called "groundwater depression wetlands". (ex. fens) Wetlands watered by surface precipitation are called "surface water depression wetlands." (ex. bogs) Similarly there are "groundwater slope wetlands" and "surface water slope wetlands." Marsh vegetation vs. Swamp vegetation - Answers Herbaceous emergent vegetation Woody emergent vegetation Both are "open systems" - fed by river or streams Productivity: Land vs. Wetland - Answers Wetland has far more productivity than terrestrial habitats. Sequencing ranking of species - Answers Terrestrial (Old Field) Mid Reach Headwaters Large River Marine Lotic aquatic systems - Answers flowing water, such as rivers and streams. Lentic habitats - Answers are still water sites such as lakes or impounded water behind dams. (Lake Like) Zonation - Answers Zonation of vascular plants is characteristic of all wetlands, with plants distributed along an elevation gradient from within the water column to the water's edge to truly upland habitats. Different Zones of Vegetation - Answers Emergent Vegetation: cat tails and bulrushes that grow in the water, but whose upper plant bodies emerge from the water surface Floating leaf Vegetation: lily pads whose roots are attached to the bottom, but whose leaves and flowers are on the surface Submergent Vegetation: Not emerging from the water Limitations of vascular plants - Answers Vascular plants usually need to pollinate and photosynthesize, thus are limited by water depth in freshwater habitats. When the water is too deep for the vascular plants to establish roots and reach the photic zone, they are absent. These areas are open water or pelagic habitat. Ecological succession - Answers Ponds and lakes are examples of ecological succession. A standard successional pattern beginning with an open pond that gradually fills up with sediment, eventually becoming prairie or wet meadow. Riparian vegetation - Answers • Grows along flowing rivers, streams, and also around ponds. • Not characteristic of lakes or reservoirs. • Natural sponge holding nutrients and purify water and release it slowly. • Values: aesthetic, cultural, archaeological and biocentric Three Different habitats within rivers - Answers 1) Meanders - bends in a river 2) Pools - still, deeper areas 3) Riffles - shallow, fast flowing areas River Meanders - Answers "bends in a river" Erosion occurs on the outside of the bend, and deposition of sediment occurs on the inside of a bend, forming "point bars" of gravel and sand. Lotic Zones - Answers 1) Zone of erosion of sediments • Where head waters and small tributaries come together at high elevation 2) Zone of storage and transport of sediments 3) Zone of deposition of sediments Alterations to rivers and streams - Answers Channelization Straightening Diversion LA River - Answers 378 km long. 83% concrete lined, 6% straightened, and only 12% is natural. Ultimate base level - Answers • All streams and rivers erode toward the "ultimate base level"(sea level). • If a river is dammed, a new base level (the level of the reservoir) replaces the ultimate base level. River Division: Zone of erosion - Answers • Headwaters of a river comprise many low order (small) tributaries • Have a steep gradient, high elevation • Fixed channel with a deep V-shaped valley. River Division: Zone of transport of sediment - Answers • Gradient is moderate • The valley opens up/widens from the upstream canyon. River Division: Zone of Deposition of Sediment - Answers • Low gradient • Broad valley • Lots of sediment, pools, riffles, and tight meanders. Oxbow Lake - Answers Where the stream meanders (bends) and become narrower and narrower at their origin from a river - eventually the mouth plugs with silt and clay, isolating the bend. Eventually the "lake" itself (the crescent shaped remnant of the river bend) will fill in, and become a "meander scar." An oxbow lake may only get filled after a major flood. Invasive species impact on the native species - Answers • Behavioral • interference • predation • competition • high tolerance of degraded habitat by the invasive species. Impact of Invasive Species - Answers 1) Population crashes and extinctions 2) Community structure change Types of Fish - Answers 1) Primary freshwater fish can live only in fresh water. 2) Secondary freshwater fish can live in fresh water as well as in salt water (e.g. pupfish). 3) Truly marine fishes can only live in salt water. Anadromous Fish - Answers •Lay eggs in fresh water, migrate to the ocean to mature and return to the river and oligotrophic headwater streams to spawn • Some are limited to one reproductive cycle and die after spawning (salmon). • After hatching, the young fish leave fresh water and return to the ocean to feed and mature because in the temperate latitudes the ocean is more productive than the oligotrophic headwater streams (freshwater tributaries). West Coast Salmon - Answers Do not eat after leaving the ocean and depend on their diminishing fat supply to get them to the spawning areas. Example is the Sockeye Salmon Catadromous fish - Answers • Fish migrate from the ocean to feed in fresh water, but reproduce in estuarine or marine environments. • Most common in the tropics and subtropics because the tropic freshwater tributaries are more productive than the relatively sterile oceans. Stream Order - Answers (based upon stream width) ranges from 1 (less than a meter wide) to 12 at 700 meters in width.