Ecology Ch. 21

Milne’s study of Admiralty Island’s coastline found that length of the coast decreased as the length of the “ruler” increased

Which three of the following are considered to be distinct to landscape ecology? Interdisciplinary; spatial heterogeneity across scales; includes human activity

Match the organism to its “environmental engineering” effect

Drought refugees: alligators

Soil development: termites; kangaroo rats

Grassland conversion: elephants

The perennial plant Ambrosia deltoidea (genus and species) dominates the soils of the middle to late Pleistocene in the bajadas region

During Webster’s study, the change in lake level during a drought period depended upon where the lake was in the hydrologic flow. Rank the following locations, from greatest to least, based upon the change in lake level that occurred during the drought. Middle; upper; bottom

The matrix is the element within a landscape mosaic that is considered to be the most spatially continuous

Which of the following characteristics of landscape elements would define landscape structure? Position; size; shape; composition

The distinctive area of ecological conditions and higher species richness on either side of an ecotone is known as the edge effect

Which of the following are ways that humans have cut the connections between rivers and their flood plains? Channelization; dams; levees; flow diversion

The role of humans and human disturbance has been incorporated into landscape ecology from the beginning

Match the plant type with the soils where they are most abundant in the bajadas region.

Larrea – Holocene and early Pleistocene

Ambrosia – middle to late Pleistocene

Other perennials – eroded Pleistocene

Landscape ecology is the study of the relationship between spatial pattern and ecological process

Which of the following of the geologic processes are the primary source of landscape structure? Erosion; volcanism; sedimentation

Which of the following are ways that floods modify the riverine landscape? Creating channels; silt deposition; isolating lakes; increased decomposition

Organisms that change the physical environment and influence landscape structure are known as ecosystem engineers

Which of the following processes are responsible for the distinctive landforms of the Sonoran Desert bajadas? Erosion; deposition

Haddad and Baum found that corridors increased the frequency of movement of butterflies between patches

The restricted movement of organisms between habitats resulting from an increase in habitat fragmentation may result in local population extinction

Originally, the Kissimmee River was a braided channel flowing southward into Lake Okeechobee

Hanski et al found that butterfly populations increased with patch area

Ecosystem engineers are organisms that can alter the physical environments suffieciently to influence changes in which of the following? Landscapes; ecosystems; communities

Rivers and their associated flood plains are connected through floods

Edges of habitats that are characterized by transitions of physical and biological characteristics with the adjacent habitat are known as ecotones

Which of the following are environmental changes resulting from kangaroo rat burrows? Modification of soil structure; alteration of the distribution of plants; alteration of soil nutrients

Benoit Mandelbrot developed fractal geometry as a method for describing the dimensions of natural objects

The study of fragmentation by Hanski et al studied butterflies in a landscape that contained which of the following habitats? Cultivated fields; woods; small farms; pastures

Which of the following research projects would be considered to be within the field of landscape ecology? Foraging behavior of sheep on a hillslope; transmission of a pathogen along a river corridor

The process of reconnecting rivers to their flood plains is known as river restoration

Within a landscape, patches form the mosaic that is called landscape structure

The focus of the Haddad and Baum study on patches was to examine the role of corridors on organism movement

Geological processes such as volcanism, sedimentation and erosion are the primary source of landscape structure. TRUE

The food plant used by the butterflies generally occurs in only which of the following habitats? Pasture; meadows

Which of the following did Naiman propose for the increased nutrient storage in beaver impoundments? Alteration of biogeochemical cycles; entrapment of eroded materials; capture of nutrients formerly used by plants

Haddad and Baum created patches by cutting forest in order to study butterfly movement

The area of mathematics that is used to quantify the structure of complex natural shapes in known as fractal geometry

The Kissimmee River would often flood 94% of its flood plain for six months and would remain flooded for periods of up to four years

Within landscape ecology, a homogeneous area that differs from surrounding areas is known as a patch

Which of the following are ways that water managers will change landscape structure and process as part of the Kissimmee River restoratiorn? Recreate complex channel networks; reestablish flood plains; restore river-floodplain connections; restore flood pulses

Discontinuities in a habitat, often the result of disturbance, that can result in restricting the movement of organisms within habitats is known as fragmentation

Hanski et al found that the best measure of patch isolation was a combination of which of the following factors? Distance between patches; number of butterflies in a patch

Which of the following describes the species found in ecotones? They are unique to the ecotone; there are a mix of species from the adjacent habitats

Which of the following are the result of beaver activity on the landscape? Nutrient trapping; altered hydrology; increased wetlands; forest patchiness

The Veluwe was originally dominated by mixed forests

Which of the following within landscape structure influence the movement of organisms between habitats? Size; number; isolation

In general, you would expect species richness of ecotones to be greater than that of the adjacent habitats

Which of the following are landscape characteristics that differed between sites in the Bowers and Burgess study? Number of forest patches; patch shapes; total forest cover; patch area

In their study of fragmentation in prairie grasslands, Diffendorfer et al used mowing to create habitat patches of differing sizes

In his study of Admiralty Island coastline, Milne based his “big” ruler on the distance between bald eagle nests

The demand for flood control on the Kissimmee River was driven by flooding and population growth

Which of the following did Naiman propose for the increased nutrient storage in beaver impoundments? Entrapment of eroded materials; capture of nutrients formerly used by plants; alteration of biogeochemical cycles

Minnich hypothesized that the difference in landscape structure between southern California and Baja California is the result of a difference in fire history

In Webster’s study, the combined concentrations of the cations Ca2+ and Mg2+ increased most in the lakes of which region of the hydrologic flow system? Lower

The changes in land cover in Veluwe Netherlands are most similar to those of the US Northeast resulting in an increase of forest cover

Overall, the results from the Diffendorfer et al study were supportive with respect to their original hypotheses

Based upon Milne’s fractal analysis, the coastline of Admiralty Island that an eagle “sees” is less than that “seen” by a barnacle

The location of a lake within a hydrologic flow system is known as its landscape position

Flood control on the Kissimmee resulted in a reduction in the populations of waterfowl and sport fish

In general, McAuliffe found that in the bajadas, the oldest soils were found at the southern end of the range

The activities of beaver increase the extent of wetlands in the landscape

Minnich found that between 1972 and 1980 the total burned area in southern California was similar to that in Baja California

During the course of their study, Hanski et al observed several populations go extinct. These occurred on small patches with small populations

Webster et al concluded that the increased mass of cations in the lakes at the lower end of the hydrologic system was the result of increased ground and surface water flows

Fire suppression in southern California increased as a result of urbanization

In Bowers and Burgerss’ patch shape formula: the “P” term represents patch perimeter

In the Kabetogama Peninsula, beaver activity resulted in an increased of nutrient entrapment in impoundments

In a pilot study for Kissimmee River restoration, it was found that fish requiring higher levels of dissolved oxygen responded in which manner? Positively

In fragmented habitats, organisms were predicted to move longer distances in order to find mates, food and cover

According to Naiman, the loss of forest vegetation near beaver impoundments would result in an increase in nutrient capture

During the period between 1831 and 1950 the area of forest increased due to regrowth on abandoned farms in Cadiz, Wisconsin. FALSE

As a result of early human activity, the Veluwe became dominated by healthlands

Minnich found that between 1972 and 1980 the number of large burns in southern California was greater than that in Baja California

In general, flood control on the Kissimmee River resulted in a transition from rivering species to those typically found in lakes

In general, McAuliffe found that in the bajadas, the age of the soils decreased when moving south to north

The focus of Diffendorfer et al research on prairie fragmentation were rodents

The difference in coast length “seen” by barnacles and eagles is a result of a difference in their rulers

Studies on patches and corridors found that corridors increased rates of pollination in plants

In Bower and Burgess’ patch shape formula, when S = 1, the patch is circular in shape

The red color of the argillic soils is the result of iron being deposited during periods of intermittent wetting

From the beginning of the beavers’ reintroduction until 1988, the landscape of the Kabetogama Peninsular changed from being dominated by boreal forests to complex habitat mosaic

A hardpan soil layer formed by the precipitation of CaCO3 is known as caliche

In Bower and Burgess’ patch shape formula, patches with a more elongate shape will have a value of S > 1

The red color of the argillic soils is the result of a buildup of oxidized iron

Ecology Ch. 20

Ecological succession would occur after the: formation new rocks from volcanism; removal trees after a major avalanche; retreat of a glacier leaving bare ground

The inhibition model predicts that early colonists prevent the colonization of later arrivals

A community that remains the same over time is termed stable

During succession, ecosystem properties change along with the changes in diversity and composition of species

Connel and Slatyer (1977) proposed three models of succession that include inhibition; tolerance; facilitation

When analyzing the Park Grass Experiment at the species level, the community appeared to be: unstable

In the Hawaiian Islands, nutrient availability changes over time by more phosphorous is retained in the ecosystems; phosphorus becoming the limiting nutrient

During the later stages of primary succession the rate of increase for species diversity begins to plateau

Some communities are stable because they are resilient; lack disturbance; are resistant to change

During primary succession at Glacier Bay, Chapin et al. 1994 has shown that total soil depth increases over time

During community succession, which of the following changes are likely to occur? Changes in the composition of species; increases in species richness

As the community at Glacier Bay goes from a pioneer community to the spruce stage, organic content of the soil increased; moisture content increased

Liken’s group in 1969 observed that nitrogen loss during succession returned to predisturbance levels in less than 5 years

During the early stages of succession, pioneer species colonize new habitat and modify it so that it facilitates the establishment of later succession

If early successional species are susceptible to various sources of mortality, it would support the: inhibition model

Based on Connell and Slatyer’s tolerance model of succession, later successional species are more tolerant of the conditions found in later successional stages; pioneering species do not facilitate colonization

An older community that appears to remain stable in the absence of disturbance is called a: climax community

In the Piedmont Plateau of the eastern US, Keever’s 1950 experiment demonstrated that Aster is important for the growth of Andropogon; the growth of Aster is inhibited by Erigeron

Early studies of the soils in the Hawaiin Islands indicate that primary production is initially limited by nitrogen

In the Hawaiian Islands, Hedin, Vitousek, and Matson used a chronosequence to show that organic matter increased in the soil for the first 150,000 years

After surviving a hurricane, a mangrove forest maintains its basic structure and functioning. This community would be considered: resistant

During the steady state phase of ecosystem recovery, biomass will fluctuate around a mean level

During primary and secondary succession, ecosystem properties that can change include: biomass; nutrient retention; primary production

After nearly two months, the diversity of diatoms and algae began to decline

Similar to forests, species richness in the intertidal zone increased following a logarithmic pattern

The rate of succession can be fastest on rocks in the marine intertidal zone

After about 150 years of secondary succession in the piedmont, which types of plants become dominant? Oaks and hickory

During primary succession, the alder stage facilitates spruce seedlings by increasing organic matter in the soil

Valett’s team found that Sycamore Creek was stable after intense flooding because the spatial arrangement of downwelling and upwelling areas remained constant

Succession taking place on a newly formed volcanic island would be known as: primary succession

How we determine community stability is a function of the: level of resolution when a community is analyzed; time scales involved; spatial scales involved

Stability in Sycamore Creek, Arizona, is due in part to the stability of the underlying bedrock

If a community is affected by a disturbance, but returns to its original state, then this community would be considered resilient

Based on Valett’s (1994) work on Sycamore Creek, Arizona, upwelling zones were found to be more resilient to disturbance

Regions in Sycamore Creek, Arizona, with higher nitrate concentrations are associated with upwellings and have higher algal production

The Park Grass Experiment demonstrated that fertilizing with nitrogen, phosphorus, potassium, sodium, and magnesium increased the proportions of other plants; reduced the dominance of grasses

When fields are abandoned, one of the first colonizing species is: crabgrass

Sycamore creek generally has low flows; however, flash floods are a source of disturbance; can initiate succession; remove organisms from the creek

After intense flooding in a stream, what are the first organism to colonize the streambed? Diatoms

Souse showed that succession on intertidal boulders was similar to forest succession, species richness increased with time

Calcium and potassium losses in a recovering ecosystem can remain elevated even after 7 years of succession

Intense flooding in Sycamore Creek, Arizona, had no effect on the locations of upwelling and downwelling reaches

A model of succession that proposes pioneer species are able to colonize new habitat first is called the: facilitation model

In Sycamore Creek, Arizona, algal production is often higher in regions with positive vertical pressure

When succession takes place on newly exposed geological features, it is known as: primary succession

Turner (1983) found that Phyllospadix seeds were all attached to middle successional algae. This observation supports the: facilitation model

Many areas of the Piedmont in eastern North America were clearcut and later abandoned

Open space in the rocky intertidal zone is created by winter storms that generate high waves

Similar to Glacier Bay, during succession, the species richness of woody plants in the Piedmont Plateau increases in a logarithmic pattern

Based on the study of Hedin et al., as the Hawaiian Islands age, total nitrogen is lower at sites that are 1.1 and 1.4 million years old compared to sites that are 150,000 years old

The types of birds typically found in the first two years of secondary succession are typically associated with grasslands

In 1979, Sousa removed middle successional species from experimental plots which were then colonized by late successional species. This result supported the inhibition model for succession

Although there is annual variation in the proportion of grasses, legumes and other plants in the Park Grass experiment, the proportions of the three groups were very similar over the course of the study

During the early states of succession in streams, algal biomass increases rapidly

The community in the Park Grass experiment has remained stable for over 150 years. This indicates that the species composition has remained relatively unchanged

Requirements to study community stability include: long time scales

When disturbance severely disrupts a community, the succession that takes place is known as: secondary succession

Pioneer communities recently established from the retreat of glaciers are typically dominated by Epilobium, Equisetum, and Salix

In a community undergoing primary succession, which group of plants took about a century before species richness began to plateau? Mosses and liverworts

The study sites at Glacier Bay, Alaska, include a set similar forest, but at different ages. This represents a chronosequence

A pioneering plant would be a plant that is the first to colonize newly created habitat

According to Grimm (1987), during the early stages of stream succession in Sycamore Creek, dissolved inorganic nitrogen entered and left the stream in roughly equal amounts

In the Hawaiian Islands, primary production in older soils is limited by: phosphorus availability

In Sousa’s experiments in the rocky intertidal zone, he removed middle successional species from rocks and found that late successional species recolonized the rocks

Which group of plants continued to increase in diversity throughout primary succession? Low shrubs and herbs

The piedmont of eastern North America has many areas of deciduous forest undergoing secondary succession

Based on Johnston and Odum (1956), the changes in avian diversity closely resemble the increase in woody plant diversity

A major spring flood in a river removed all of the vegetation along the stream bank. The subsequent return if the community is known as: secondary succession

During succession in Sycamore Creek, AZ, nitrogen retention increased rapidly and eventually leveled off after about 28 days

The first plants to grow in an area where new substrate has been created would form a: pioneer community

The increase in species richness in Glacier Bay and the Piedmont Plateau can be described as: logarithmic

Turner (1983) found that Phyllospadix seeds were all attached to middle successional algae. This observation supports the: facilitation model

Open space in the intertidal zone is often colonized first by Ulva in May

One major problem that faced ecologists trying to study community stability is that: long time scales are required

In the Park Grass Experiment, the proportion of plants, including grasses and legumes, vary from year to year based mainly on annual variations in precipitation

In the rocky intertidal zone, the establishment of Phyllospadix is dependent on the presence of middle successional of middle successional algae

When a piezometer measures a positive vertical gradient, this would indicate water flow from the streambed to the stream

Many of the insects that live in Sycamore creek are terrestrial as adults

When a piezometer measures a negative vertical gradient, this would indicate a downwelling zone

After a flood in Sycamore Creek, how did aquatic insects recolonize the stream? Many of the adults are terrestrial, and laid eggs in the stream after the flood

Ecology Ch. 19

Examples of carbon sinks, locations where carbon is relatively unavailable for long periods of time, include: fossil fuels, carbonate rock, soil

Atmospheric forms of carbon include carbon dioxide and methane gas (CH4)

The concentration of atmospheric carbon has increased since the onset of the industrial revolution

In a study done, nitrate export in streams draining watersheds in Baltimore County, Maryland, it was shown that land use affects the average nitrogen concentration. Rank the average nitrogen concentrations in the streams from lowest to highest. Forested area; urban area; suburban area; agricultural area

A friend tells a woman that some of the carbon in her body could have once been found in a dinosaur. The woman should: agree because elements cycle through the environment

Organic molecules such as hemoglobin, contain not only carbon, hydrogen, and oxygen, but also nitrogen. This element is also crucial to primary production and is relatively scarce.

Nitrogen in the atmosphere is: the main pool of nitrogen in the environment; converted to other forms by algae; converted to other forms by cyanobacteria

When nitrogen is converted from an organic form to an inorganic form, the process is called mineralization. This process mainly takes place during the breakdown of organic matter and is called decomposition

The main sources of phosphorus in the ecosystem are: mineral deposits such as rocks; marine sediments

When a specific nutrient is absorbed faster than it is released into the environment, this type of nutrient pool is called a nutrient sink

Plants are assisted in their uptake of phosphorus from the soil due to their interaction with mutualistic mycorrhizal fungi

Phosphorus (or phosphate) can enter aquatic environments: as runoff from land following the melting of snow; as runoff from land following rain storms; as runoff from fertilized farm fields

The burning of fossil fuels has become a major source of atmospheric carbon dioxide

Which of the following molecules in living organisms do NOT contain phosphorus?

Ribose sugar

Does contain: ATP; RNA; phospholipids; DNA

Examples of human (anthropogenic) sources of nitrogen enrichment include: runoff from agricultural land into waterways; burning of fossil fuels

Increased population densities are associated with: increased nitrogen enrichment of river ecosystems

In a nutrient cycle, chemicals are stored in nutrient pools or compartments

Concerning the movement of phosphorus through the environment: phosphorus can move from rivers into oceans

Sedimentary rocks rich in phosphorus are mined for fertilizer

Which of the following are true?

Plants growing in low-nutrient ecosystems allocate more resources to root growth compared to shoot growth

Plants growing in high-nutrient ecosystems grow at a faster rate than those in low-nutrient ecosystems

Nutrient enrichment of an aquatic ecosystem that can be due to human activities is called eutrophication. It can result in water quality problems

Carbon dioxide is removed from the atmosphere by the process of photosynthesis

Animals gain phosphorus, in the form of phosphate, by: ingesting plants that contain phosphate; ingesting other animals that contain phosphorus compounds

Decomposition rate is mainly affected by moisture levels, the chemical composition of litter and the environment, and temperature

Which of the following is correct concerning the movement of carbon between organisms and the environment? Respiration returns carbon to the atmosphere in the form of carbon dioxide

An example of a nutrient source would be: burning of fossil fuels that add carbon dioxide to the atmosphere

Phosphorus is essential to living organisms. For example, phosphorus is the main component of cell membranes when it is combined with lipids to form phospholipids

Which of the following molecules found in living organisms do NOT contain nitrogen? Cellulose (fiber)

Does contain: proteins, such as hemoglobin; chlorophyll; nucleic acids, such as DNA

Which of the following molecules found in living things always contain carbon? Lipids; carbohydrates; proteins

In major river ecosystems, such as the Mississippi, Thames, and the Amazon, the single variable that appeared to explain most of the variation in nitrate concentration and export was human population density

Burning of fossil fuels has increased the concentration of CO2 in the atmosphere since the industrial revolution, despite oceans acting as carbon sink

The conversion of nutrients such as phosphorus from an organic form to an inorganic form is called mineralization

Research done by Takyu, Aiba, and Kitayama indicates that higher concentrations of phosphate in the soil are associated with: higher rates of decomposition; increased rates of leaf litter fall

Areas that may have high levels of CO2 uptake (vs. output) that are reducing the predicted effects of increased burning of fossil fuels are referred to as being the “missing carbon sinks”

In a river or stream where nutrient spiraling is occurring, nutrients may be used many times (cycled) before leaving a stream system, when: the spiraling length is short

In the study done by Meyer and Likens on the movement of phosphorus in the Bear Brook ecosystem, inputs to the ecosystem included: precipitation; seeps

One way humans overcome nitrogen limitation to plant growth is to rotate crops capable of nitrogen fixation with crops that have high nitrogen needs. These crops add ammonium to the soil

Work done by McNaughton, Ruess, and Seagle, indicate that large grazing animals, such as bison: speed up nutrient cycling in an ecosystem

Nutrient cycling can be affected by animals transporting nutrients from one ecosystem to another. An example of this are the Pacific salmon that spend most of their lives at sea. However, after spawning in streams and lakes, the salmon die and their carcasses are utilized by other organisms

In suburban areas, one contributor to increased nitrate input to stream ecosystems can be the presence of septic systems

Because water currents move nutrients downstream, Webster coined the term nutrient spiraling to describe stream nutrient dynamics

Which of the following could explain the high level of nitrogen retention in suburban watershed areas? Riparian areas; actively growing lawns

Decomposition rates in tropical environments are lower than in temperate ecosystems. FALSE

Using the graph, results from research on decomposition rates show: plants with higher toughness: nitrogen rations lost less mass

Nitrogen can enter the nutrient cycle through fixation by living organisms or through the energy and pressure generated by lightning

As shown in the Gallardo and Merino study, elevated moisture levels have a positive effect on leaf decomposition

Using the graph as an aid, during years of high streamflow, Bear Brook: exports of phosphorus were greater than inputs

One form of deforestation, which involved removing all trees from an area is called clear-cutting. When this occurs, nitrate losses from the environment increase

Pocket gophers may increase plant diversity by increasing the heterogeneity of nutrient availability in the soil

Denitrification: is energy producing and is carried out by bacteria

Using the graph, the results of the Gallardo and Merino experiments showed: higher levels of precipitation are associated with higher levels of leaf decomposition

Animals may gain nitrates from ingestion of plants. When these animals die, the animals decompose. This decomposition leads to the production of ammonium. Eventually, bacteria convert ammonium to nitrate in the process called: nitrification

Because plant growth is dependent on nitrogen, and fixed nitrogen is relatively low in abundance, humans add fertilizer to the soil to increase crop production

In the Serengeti ecosystem it was shown by McNaughton, Ruess, and Seagle that: grazing by large herbivores resulted in biomass turnover in less than one year

In the nitrogen cycle, nitrogen is returned to the atmosphere through the process of: denitrification

Using the graph, results from research on decomposition rates forests show: the toughness of plant leaves is inversely related to decomposition rates

Because higher evapotranspiration rates increase the rate of decomposition, decomposition in temperate ecosystem is usually lower than in tropical ecosystems

In the experiment performed by Likens and Bormann on the effects of deforestation on nutrient cycling, inputs to the stream ecosystems include weathering of granite bedrock and precipitation

Fungi and bacteria release nitrogen as ammonium through the process called: ammonification

The effects of leaf litter chemistry on decomposition in Mediterranean woodland ecosystems were studied by Gallardo and Merino

In a study performed by Gallardo and Merino to investigate the effects of litter chemistry on decomposition, the mesh bags contained holes 1mm large. This allowed aerobic microbial activity and small soil invertebrates to aid in decomposition

Using the graph as an aid, during years of low streamflow, Bear Brook: stores phosphorus

In a stream ecosystem, nutrient retentiveness is inversely related to spiraling length, meaning that as one value increases, the other value decreases

Suberkropp and Chauvet showed that as nitrate levels in a stream increased, decomposition of yellow poplar leaves: increased

The term nutrient spiraling was coined by the scientist named Jack Webster

Bison tend to feed on grasses that are near prairie dog mounds because the grasses are higher in nitrogen content

Research results (Mellillo and colleagues) from two temperate forests suggest that higher decomposition rates of leaf litter in a North Carolina forest compared to a forest compared to a forest in New Hampshire may be due to greater availability of the nutrient nitrogen in the soil

Many detritivores reingest nutrients such as nitrogen by eating their feces

Work done by Rosemond and colleagues suggest that leaf decomposition rate increases in the presence of increased phosphorus concentration

In the Hawaiian ecosystem, it was shown that the introduced Myrica tree altered the nitrogen content in the soil

In a study done by Meyer and Likes, it was shown that in the Bear Brook ecosystem, there were annual pulses of phosphorus import and export. However, most phosphorus export was irregular because it was associated with: flooding caused by storms

Gessner and Chauvet determined that higher lignin content in plant materials inhibits colonization by fungi that are mainly responsible for decomposition of leaves in stream habitats

The results of experiments done by Suberkropp and Chauvet on the effects of nitrate on decomposition in freshwater had results that were consistent with the study done by Melillo on how soil nitrogen content affects decomposition

Gallardo and Merino were the scientist who studied how chemical differences in leaves, such as lignin concentration, affect decomposition in woodland ecosystems. TRUE

The scientist who described how nutrients in streams are subject to downstream transport, causing cycling to NOT occur in one place is named: Jack Webster

In stream ecosystems, spiraling lengths that are short are associated with high nutrient retentiveness

Work done by Whicker and Detling found that: prairie dog grazing results in young grass tissues high in nitrogen content

In the study performed by Grimm: the 10% of nitrogen tied up in macroinvertebrate biomass lowers V in the equation for spiral length

Based on research done in temperate forests by Melillo and colleagues, plants with lower lignin: nitrogen rations decomposed at a higher rate

In the Hawaiian ecosystem, the Myrica tree was introduced. Compared to the native trees in the Hawaii Volcanoes National Park, it: has leaves that decompose at a higher rate

Results of a study done on yellow poplar leaf decomposition in a stream habitat by Suberkropp and Chauvet indicated that: higher nitrate concentration resulted in higher decomposition rates

At high phosphorus levels: leaf decomposition rates level off at high values

Grimm’s study showed that macroinvertebrates appear to affect the spiraling of nitrogen in aquatic habitats by: reingestion of nutrients by the macroinvertebrates resulting in increased primary production