Nitrogen and Weeds
Fargione, J., Brown,
C.S., Tilman, D. 2003. Community
assembly and invasion: An experimental test of neutral versus niche processes. Colorado
State University, Fort Collins, CO 80523
Weeds can target areas of high diversity which may also have
elevated N.
Stohlgren T.J., Binkley
D., Chong G.W., Kalkhan M.A., Schell L.D., Bull K.A., Otsuki Y., Newman G.,
Bashkin M., Son Y. 1999. Exotic plant species invade hot spots of
native plant diversity. Ecological
Monographs 69 (1): 25-46.
Tilman, D. 1982. Resource competition and community
structure, Monographs in population biology. Princeton
University Press, Princeton,
New Jersey, USA.
Tilman, D. 1987. Secondary
succession and the pattern of plant
dominance
along experimental nitrogen gradients. Ecological
Monographs
57:189214.
Tilman, D. 1988. Plant strategies and the dynamics and
structure
of plant communities. Monographs in population biology.
Princeton
University Press, Princeton, New
Jersey, USA.
Tilman, D. 1989. Competition, nutrient reduction, and the
competitive
neighborhood of a bunchgrass. Functional Ecology
3:215219.
Tilman, D. 1990. Constraints and tradeoffs: toward a
predictive
theory of competition and succession. Oikos 58:315.
Tilman, D. 1994. Competition and
biodiversity in spatially
structured
habitats. Ecology 75:216.
Tilman, D., May, R. M. , Lehman, C.L., Nowak, M.A.
1994. Habitat destruction and the extinction debt. Nature
371:6566.
Abstract
Habitat destruction is the major cause of species
extinctions1?3. Dominant species often are considered to be free of this threat
because they are abundant in the undisturbed fragments that remain after
destruction. Here we describe a model that explains multispecies coexistence in
patchy habitats4 and which predicts that their abundance may be fleeting. Even
moderate habitat destruction is predicted to cause time-delayed but
deterministic extinction of the dominant competitor in remnant patches. Further
species are predicted to become extinct, in order from the best to the poorest
competitors, as habitat destruction increases. More-over, the more fragmented a
habitat already is, the greater is the number of extinctions caused by added
destruction. Because such extinctions occur generations after fragmentation,
they represent a debt?a future ecological cost of current habitat destruction.
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Tilman, D., D. Wedin, and J. Knops. 1996. Productivity and
sustainability influenced by biodiversity in grassland
ecosystems.
Nature 379:718720.
Abstract
The functioning and sustainability of ecosystems may depend
on their biological diversity1?8. Elton's9 hypothesis that more diverse
ecosystems are more stable has received much attention1,3,6,7,10?14, but
Darwin's proposal6,15 that more diverse plant communities are more productive,
and the related conjectures4,5,16,17 that they have lower nutrient losses and
more sustainable soils, are less well studied4?6,8,17,18. Here we use a
well-replicated field experiment, in which species diversity was directly
controlled, to show that ecosystem productivity in 147 grassland plots
increased significantly with plant biodiversity. Moreover, the main limiting
nutrient, soil mineral nitrogen, was utilized more completely when there was a
greater diversity of species, leading to lower leaching loss of nitrogen from
these ecosystems. Similarly, in nearby native grassland, plant productivity and
soil nitrogen utilization increased with increasing plant species richness.
This supports the diversity?productivity and diversity?sustainability
hypotheses. Our results demonstrate that the loss of species threatens
ecosystem functioning and sustainability.
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and Ecosystem Function (eds Schulze, E. D. & Mooney, H. A.) 361?384
(Springer, Berlin, 1993).
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J. A. Nature 367, 363?365 (1994). | Article | ISI |
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307, 321?326 (1984). | Article | ISI |
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(in the press).
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Anderson, J. M. in Biodiversity and Ecosystem Function (eds Schulze,
E. D. & Mooney, H. A.) 15?41 (Springer, Berlin, 1993).
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J., Lawler, S. P., Lawton, J. H. & Woodfin, R. M. Phil. Trans. R. Soc.
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and Ecosystem Function (eds Schulze, E. D. & Mooney, H. A.) 255?270
(Springer, Berlin, 1993).
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Givnish, T. J. Nature
371, 113?114 (1994). | Article | PubMed | ISI |
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21.
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Tilman, D., Downing, J.
& Wedin, D. Nature 371, 114 (1994). | Article |
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22.
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Andre, M., Brechignac, P.
& Thibault, P. Nature 371, 565 (1994). | Article | ChemPort |
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23.
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Naeem, S., Thompson, L.
J., Lawler, S. P., Lawton, J. H. & Woodfin, R. M. Nature 371,
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Tilman, D. Oikos 58,
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McKane, R. B., Grigal, D.
F. & Russelle, M. P. Ecology 71, 1126?1132
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Turelli, M. 1981. Niche overlap and invasion of competitors
in random environments. 1. Models without demographic
stochasticity. Theoretical Population Biology 20:156.
Abstract
The relationship between persistent, small to moderate
levels of random environmental fluctuations and limits to the similarity of
competing species is studied. The analytical theory hinges on deriving
conditions under which a rare invading species will tend to increase when faced
with an array of resident competitors in a fluctuating environment. A general
approximation scheme predicts that the effects of low levels of stochasticity
will typically be small. The technique is applied explicitly to a class of
symmetric, discrete-time stochastic analogs of the Lotka-Volterra equations
that incorporate cross-correlation but no autocorrelation. The random
environment limits to similarity are always very close to the corresponding
constant environment limits. However, stochasticity can either facilitate or
hinder invasion. The exact limits to similarity are extremely model-dependent.
In addition to the symmetric models, an analytically tractable class of models
is presented that incorporates both auto- and cross-correlation and no symmetry
assumptions. For all of the models investigated, the analytical theory predicts
that small-scale stochasticity does little, if anything, to limit similarity.
Extensive Monte Carlo results are presented that confirm the analytical results
whenever the dynamics of the discrete time models are biologically reasonable
in the sense that trajectories do not exhibit unrealistic crashes.
Interestingly, the class of stochastic models that is well behaved in this
sense includes models whose deterministic analogs are chaotic. The qualitative
conclusion, supported by both the analytical and simulation results, is that
for competitive guilds adequately modeled by Lotka-Volterra equations including
small to moderate levels of random fluctuations, practical limits to similarity
can be obtained by ignoring the stochastic terms and performing a deterministic
analysis. The mathematical and biological robustness of this conclusion is
discussed.
Usher,
M. B. 1988. Biological invasions of nature reserves: A search for
generalizations.
Biological Conservation. 44:(1-2) 119-135
Abstract
Each one of the 24 nature reserves in the preceding case
studies has received introduced species of plants and vertebrates (and
invertebrates where the data exist). Some of these have become invasive,
although the probability that an island nature reserve is invaded is greater
than a savanna or dry woodland. Arid lands and Mediterranean-type reserves
showed a negative relationship between the proportion of species that are
introduced and the reserve's area. Examples demonstrate that after a period of
about 1000 years it is difficult to distinguish between native and introduced
species.
Invasive species affect both the structure and function of
an ecosystem. Management priority has to be given both to invasive species that
threaten endemic species with extinction and to species that have a strong
landscape effect. The cost of controlling invasive species can utilise a large
proportion of a reserve manager's recurrent budget. Tourism poses dangers for
reserves since there is a positive correlation between visitation rate and the
number of introduced species.
The most important generalisation is that all nature
reserves, except those in Antarctica, appear
to have invasive species. Managers face the problem of how best to conserve
ecological variety.
Badgery,
W.B., Kemp, D.R., Michalk, D.L., King, W.M.C.G. 2005.
Competition
for Nitrogen between Australian Native Grasses and the Introduced Weed Nassella
trichotoma (summary not full paper)
Annals of Botany 2005 96(5):799-809;
Background and Aims Nassella trichotoma is an unpalatable
perennial grass weed that invades disturbed native grasslands in temperate
regions of south-eastern Australia.
This experiment investigated whether elevated N levels, often associated with
disturbance, increases the competitiveness of N. trichotoma relative to C3 and
C4 native Australian grasses.
Methods A pot experiment investigated competitive
interactions between four native grasses, two C3 species (Microlaena stipoides
and Austrodanthonia racemosa) and two C4 species (Themeda australis and Bothriochloa
macra), and N. trichotoma at three different N levels (equivalent to 0, 60 and
120 kg ha1) and three competing densities (zero, one and eight neighbouring
plants), using an additive design.
Key Results All native grasses were competitive with N.
trichotoma at low N levels, but only M. stipoides was competitive at high N.
High densities of native grasses (8 : 1) had a major competitive effect on N.
trichotoma at all N levels. The competitive ranking of native grasses, across
all N levels, on N. trichotoma was: M. stipoides > A. racemosa > B. macra
> T. australis. The C3 species were generally more competitive than the C4
species and C4 grasses were not inherently more productive at low N levels, in
contrast to the results of other studies.
Conclusion To resist invasion from N. trichotoma, these
native grasses need to be maintained at a high density and/or biomass. The
results do not support the theory that species such as N. trichotoma, with high
tissues density, are always less competitive than those of low tissue density;
in this case competitiveness depended on N levels. The ability of N. trichotoma
to accumulate biomass at a higher rate than these native grasses, helps to
explain why it is a major weed in disturbed Australian native grasslands.
_______________________________________________
This references numerous other studies related to weeds and
nitrogen.
Hobbs, R.J.,
Huenneke, L.F. 1992. Disturbance, Diversity, and Invasion: Implications for
Conservation. Conservation Biology, 6:(3) 324-337.
Abstract: Disturbance is an important component of many ecosystems
and variations in disturbance regime can affect ecosystem and community
structure and functioning. The "'intermediate disturbance hypothesis"
suggests that species diversity should be highest at moderate levels of
disturbance. However, disturbance is also known to increase the invasibility of
communities. Disturbance therefore poses an important problem for conservation
management Here we review the effects of disturbances such as fire, grazing
soil disturbance and nutrient addition on plant species diversity and invasion,
with particular emphasis on grassland vegetation Individual components of the
disturbance regime can have marked effects on species diversity, but it is
often modifications of the existing regime that have the largest influence. Similarly,
disturbance can enhance invasion of natural communities, but frequently it is
the interaction between different disturbances that has the largest effect. The
natural disturbance regime is now unlikely to persist within conservation areas
since fragmentation and human intervention have usually modified physical and
biotic conditions. Active management decisions must now be made on what
disturbance regime is required and this requires decisions on what species are
to be encouraged or discouraged
Wolf, J.J., Beatty, S. W., Seastedt,
T. R.. 2004. Soil characteristics of Rocky Mountain National Park grasslands
invaded by Melilotus officinalis and M. alba. Journal of Biogeography 31:1-10.
Luken, J.O., Seastedt, T.R.. 2004. Plant
invasions, management, and the conflict of perspective. Weed Technology 18:1514
-1517.
Suding, K.N.,
LeJeune, K.D., Seastedt, T.R. 2004 Competitive interactions and responses of an
invasive weed: dependencies on nitrogen and phosphorus availability. Oecologia
141: 526-535.
LeJeune, K.D., Suding, K.N., Seastedt, T.R. in press.
Nutrient availability does not explain invasion and dominance of a mixed grass
prairie by the exotic forb Centaurea diffusa Lam. Applied Soil Biology.
LeJeune, K D., KN. Suding, S. Sturgis, A. Scott and T.R.
Seastedt. in press. Biocontrol insect use of fertilized and unfertilized diffuse
knapweed (Centaurea diffusa Lamarck) in a Colorado grassland. Environmental
Entomology.
Heather E. Reed, Timothy R. Seastedt, and John M. Blair. In
press. Ecological consequences of C4 grass invasion of a C4 grassland: A
dilemma for management. Ecological Applications.
Seastedt, T.R., K.N. Suding and K.D. LeJeune. In press.
Understanding Invasions: The rise and fall of diffuse knapweed (Centaurea
diffusa) in North America. In: Inderjit (Ed.)
Invasive plants: ecological and agricultural aspects. Basal, Switzerland:
Birkhauser-Verlag AG.
Seastedt, T. R., J. M. Briggs and D. J. Gibson. 1991. Controls of nitrogen
limitation
in tallgrass prairie. Oecologia 87:
72-79.
Seastedt, T.R., P. Duffy and J. Knight. 1996. Reverse fertilization experiment
produces mixed results.
Restoration and Management Notes 14:64.
80
Reever-Morghan,
K.J. and T.R. Seastedt. 1999. Effects of soil nitrogen on non-native
plants in disturbed
grasslands. Restoration Ecology 7:
51-55.
Holford, I. C. R. (1980). Effect
of duration of grazed lucerne on long-term yields and nitrogen uptake of
subsequent wheat. Aust. J. Agric. Res. 31, 239-50.
Holford, I.C.R.
1981. Changes in nitrogen and organic carbon of wheat growing soils after
various periods of grazed lucerne, extended fallowing and continuous wheat
Australian Journal of Soil Research 19(3)
239 - 249
Extremely high rainfall for three months (534 mm) following
harvest in 1975 prevented normal fallow cultivation in early 1976, with
resultant heavy growth of weeds and volunteer wheat on the black earth but not
on the red-brown earth; less growth on the latter soil was apparently caused by
leaching of nitrogen (Holford 1980).
Abstract
Changes in total and mineral nitrogen and organic carbon were measured over a
nine year period in two contrasting soils of northern New South Wales after various durations of
grazed lucerne, extended fallowing and continuous wheat growing. At least 2 1/2
years of lucerne ley were required to raise the total soil nitrogen above the
original level on both soil types. For each year of lucerne growth the average
increase (above the control treatments) in total soil nitrogen (0-15 cm) was
equivalent to about 140 kg nitrogen ha-1 in the black earth and about 110 kg
nitrogen ha-1 in the red-brown earth. Significantly higher levels of soil
nitrogen were maintained after the lucerne treatments throughout the 9 years of
measurement on the black earth and for 5 years on the red-brown earth. Lucerne had a much larger
effect on nitrogen than on organic carbon, which was significantly increased
only in the black earth. There were very large increases in mineral nitrogen
(0-15 cm) in the first year of measurement after lucerne. Levels remained
greater than they were originally for the first 4 years, and they were greater
for 7 years in the black earth and 4 years in the red-brown earth following
lucerne than following continuous wheat or extended fallow. The decline in
mineral nitrogen during wheat cropping after lucerne was greatly increased by
excessive rainfall (574 mm or more) during the fallow. Leaching was greater in
the red-brown earth than in the black earth, and this explained occasional
differences in nitrogen uptake by wheat between the two soil types. Some
evidence suggested that under moderately moist conditions nitrogen
mineralization from lucerne-fixed nitrogen was greater in the red-brown earth
than in the black earth but under drier conditions it was less.
Weeds in Ecosystem
Stohlgren,
T.J.; Chong, G.W.; Schell, L.D.; Rimar, K.A.; Otsuki, Y.; Lee, M.; Kalkhan,
M.A.; Villa, C.A. 2002. Assessing vulnerability to invasion by nonnative plant
species at multiple scales. Environmental Management 29:566-577.
Stohlgren,
T.J.; Otsuki, Y.; Villa, C.; Lee, M.; Belnap, J. 2001. Patterns of plant
invasions: a case example in native species hotspots and rare habitats.
Biological Invasions 3:37-50.
Weeds can target areas
of high diversity which may also have elevated N.
Stohlgren
T.J., Binkley D., Chong G.W., Kalkhan M.A., Schell L.D., Bull K.A., Otsuki Y.,
Newman G., Bashkin M., Son Y. 1999. Exotic plant species invade hot spots of
native plant diversity. Ecological
Monographs 69 (1): 25-46.
Stohlgren,
T.J., Bull, K.A., Otsuk, Y.i, Villa, C.A., Lee, M. 1998. Riparian zones as
havens for exotic plant species in the central grasslands. Plant Ecology
138:(1) 113-125.
Abstract
In the Central
Grasslands of the United
States, we hypothesized that riparian zones
high in soil fertility would contain more exotic plant species than upland
areas of low soil fertility. Our alternate hypothesis was that riparian zones
high in native plant species richness and cover would monopolize available
resources and resist invasion by exotic species. We gathered nested-scale
vegetation data from 40 1 m2subplots (nested in four 1000 m2 plots) in both
riparian and upland sites at four study areas in Colorado, Wyoming, and South Dakota (a total of 320 1 m2 subplots
and 32 1000 m2 plots). At the 1 m2 scale, mean foliar cover of native species
was significantly greater (P<0.001) in riparian zones (36.3% ± 1.7%)
compared to upland sites (28.7% ± 1.5%), but at this small scale there were no
consistent patterns of native and exotic species richness among the four
management areas. Mean exotic species cover was slightly higher in upland sites
compared to riparian sites (9.0% ± 3.8% versus 8.2% ± 3.0% cover). However,
mean exotic species richness and cover were greater in the riparian zones than
upland sites in three of four management areas. At the 1000 m2 scale, mean
exotic species richness was also significantly greater (P<0.05) in riparian
zones (7.8 ± 1.0 species) compared to upland sites (4.8 ± 1.0 species) despite
the heavy invasion of one upland site. For all 32 plots combined, 21% of the
variance in exotic species richness was explained by positive relationships
with soil % silt (t =1.7, P=0.09) and total foliar cover (t = 2.4, P=0.02).
Likewise, 26% of the variance in exotic species cover (log10 cover) was
explained by positive relationships with soil % silt (t =2.3, P=0.03) and total
plant species richness (t = 2.5, P=0.02). At landscape scales (four 1000 m2
plots per type combined), total foliar cover was significantly and positively
correlated with exotic species richness (r=0.73, P<0.05) and cover (r=0.74,
P<0.05). Exotic species cover (log10 cover) was positively correlated with
log10% N in the soil (r=0.61, P=0.11) at landscape scales. On average, we found
that 85% (±5%) of the total number of exotic species in the sampling plots of a
given management area could be found in riparian zones, while only 50% (±8%)
were found in upland plots. We conclude that: (1) species-rich and productive
riparian zones are particularly invasible in grassland ecosystems; and (2)
riparian zones may act as havens, corridors, and sources of exotic plant
invasions for upland sites and pose a significant challenge to land managers
and conservation biologists.
Hobbs,
R.J.; Huenneke, L.F. 1992. Disturbance, diversity, and invasion: implications
for conservation. Conservation Biology 6:324-337
Dog Feces/Urine Characteristics
and Effects
Animal waste collection survey.
Toxins and
concentration in Dog feces -just a component of the full article
Watershed effects of
dog feces and public compliance with poop pick up -just a
component of the full article
North Virginia dog park proposed study and
summary of watershed data from the literature.
Results of the North Virginia study to determine
dog feces contribution to stream fecal coliform. Values could range from about 9% to 25%, and
wildlife was the primary contributor of the other 75%
Simmons, G.M. Jr.,
Waye, D.F., Herbein, S., Myers, S., Walker, E. 2000. Estimating Nonpoint Fecal
Coliform Sources in Northern Virginia's Four
Mile Run Watershed. The Northern Virginia
Regional Commission (NVRC) Fairfax,
VA
Referenced as a source of public behaviour and
attitudes Re: dog feces. This is a
summary , and partial report (52 pages) not the full report.
Swann,
C. 1999. A Survey of Residential Nutrient Behaviors in the Chesapeake Bay.
Widener-Burrows, Inc. Chesapeake Research Consortium. Center for Watershed
Protection. Ellicott City, MD. 112 pp.
Dog Urine effects on grass.
Speculation
on the actual cause of the lawn burn has resulted in numerous theories on what
else in the urine may be contributing to the damage. Dr. A.W. Allard, a Colorado veterinarian,
examined numerous variations in dog urine and the effects on several common
lawn grasses1. His results support the fact that volume of urine
(nitrogen content) and urine concentration had the most deleterious effects on
lawns. The pH of the urine did not have any variable effect nor did common
additives designed to alter the urine pH. Of the four grasses tested, Festuca
sp. var. Kentucky
31 (fescue) and Lolium perrene (perennial ryegrass) were the most
resistant to urine effects. In fact, the urine routinely produced a fertilizer
effect on these grasses at diluted concentrations. Poa pratensis (Kentucky
bluegrass) and Cynodon sp. var. Fairway (bermudagrass) were very
sensitive to any urine concentration and severe burns resulted, persisting
greater than 30 days after initial exposure to even four ounces of diluted
urine. Even on the most urine resistant grass tested (fescue) urine
concentration was a bigger problem than urine volume. Concentrated urine with
volumes as little as 30cc (one ounce) caused lawn burn even on fescue grasses.
Allard, A.W. 1981.
Lawn burn and dog urine, Canine Practice, March/April 1981;8;(2);26-32.
CDC (Center for Disease Control). Guidelines for Veterinarians: Prevention of
Zoonotic Transmission of Ascarids and Hookworms of Dogs and Cats. Web Site
Reference http://www.cdc.gov/ncidod/dpd/parasiticpathways/animals.htm
Finkel, A.J. 1972. Dog
feces as vector of human disease.
JAMA 1972 Sep 4;221(10):1172
No Abstract
Beaver, P.C. 1975. Biology of soil-transmitted
helminths: the massive infection.
Health Lab Sci. 1975 Apr;12(2):116-25.
Abstract
Soil-transmitted
helminth infections when invariably cause disease. A massive
infection with Ascaris
lumbricoides may cause intestinal obstruction, liver
abscess, or some other
condition requiring surgical treatment; more regularly,
however, ascaris
disease is a form of malnutrition. Trichuris trichiura causes
diarrhea and dysentery
and, at times, rectal prolapse. The hookworms, Necator
americanus and
Ancylostoma duodenale, cause blood-loss from the intestine
resulting in anemia.
Necator infection is acquired percutaneously, and is more
frequently massive than
is that of Ancylostoma which may be acquired
percutaneously or
orally. Estimates of egg output in the feces, based on
egg-counts by dilution,
direct smear, or thick-film techniques, provide a
reliable index of
light, medium, or heavy infection. Acquisition of heavy
infection with Ascaris
and Trichuris depends on favorable qualities of the soil,
and on the sorting
action of rain which transports and concentrates the eggs of
helminths in locations
where survival and transmission are favored. The high
frequency of heavy
hookworm infection in southeastern United States and probably
elsewhere may depend
largely on the presence of feces-burying dung beetles.
Human infection with
soil-transmitted helminths of dogs and cats has become a
serious public health
problem attributable to the persistence of rural mores in
the urban setting.
PMID: 1052507 [PubMed - indexed for MEDLINE]
Diseases that can be Spread Through Feces. Drs.
Foster & Smith Educational Staff Web site. http://www.drsfostersmith.com/pic/article.cfm?dept_id=0&siteid=12&acatid=196&aid=90
Basso, W., Venturini, L.,
Venturini, M. C., Hill, D. E., Kwok, O. C. H., Shen, S. K.,
Dubey, J. P. 2001. First Isolation
of Neospora caninum From the Feces of a Naturally Infected Dog. Journal of Parasitology Volume: 87 Issue: 3
Pages: 612-618
ABSTRACT
Neospora
caninum is a major cause of abortion in cattle worldwide. Cattle become
infected with N. caninum by ingesting oocysts from the environment or
transplacentally from dam to fetus. Experimentally, dogs can act as definitive
hosts, but dogs excrete few oocysts after ingesting tissue cysts. A natural
definitive host was unknown until now. In the present study, N. caninum was
isolated from the feces of a dog. Gerbils (Meriones unguiculatus) fed feces
from the dog developed antibodies to N. caninum in the Neospora caninum
agglutination test, and tissue cysts were found in their brains. Neospora
caninum was isolated in cell culture and in gamma-interferon gene knockout mice
inoculated with brain homogenates of infected gerbils. The DNA obtained from
fecal oocysts of the dog, from the brains of gerbils fed dog feces, and from
organisms isolated in cell cultures inoculated with gerbil brains was confirmed
as N. caninum. The identification of N. caninum oocyst by bioassay and
polymerase chain reaction demonstrates that the dog is a natural definitive
host for N. caninum.
Johnson, J.R., Stell, A.L., Delavari, P.
2000. Canine Feces as a Reservoir of
Extraintestinal Pathogenic Escherichia coli. VA Medical Center and Department
of Medicine, University of Minnesota, Minneapolis, Minnesota.
Horse Manure/Urine
Characteristics and Weed Seed
Horse manure nitrogen % from Cornell
composting Manual Average 1.6% dry weight
Amount and N-P-K content of horse
manure from CSU
Horse
Manure Management
J.G.
Davis and A.M. Swinker 2002
50
pounds manure/day/horse
|
Table 1: Average
fertilizer content in horse manure (as-is basis).
|
|
N/ton
|
19 lb
|
|
P2O5/ton
|
14 lb
|
|
K2O/ton
|
36 lb
|
Per
day basis N =
0.475 lbs
P2O5 = 0.35 lbs
K2O = 0.9 lbs
This
is the reference that shows seed germination from horse manure at RMNP.
Benninger,
M. C. 1989. Trail as conduits of movement for plant
species
in coniferous forests of Rocky
Mountain National
Park,
Colorado. M.S. Thesis, Miami University.
Benninger-Truax,
M. C., Vankat, J. L. & Schaefer, R. L. 1992. Trail
corridors
as habitat and conduits for movement of plant species
in
Rocky Mountain National Park,
Colorado, USA.
Landscape
Ecology.
6: 269278.
I
tracked down the primary investigator for the following horse manure/weed item:
Dr.
Sibdas Ghosh
Dominican
Univeristy
San Rafael, CA
94901
415-457-4440
sghosh@dominican.edu
The
NPS contact is:
Mietek
Kolipinski
510-817-1430
mietek_kolipinski@nps.gov
By
The Associated Press Mon
Nov 21, 2005 8:30
PM ET
SAN RAFAEL, Calif.
- Researchers are looking to horse manure to study the spread of invasive
weeds. Dominican University has received a $100,000
National Park Service grant to study how to slow the spread of nonnative plants
and weeds in state parks, school officials said. Horse manure might be part of the problem,
according to scientists.
Researchers
began collecting horse manure samples from trails and pastures this summer.
They want to test an assumption that seeds can pass through horses, leading to
sprouts of invasive weeds.
"We
need to know through scientific research if horses do or do not spread weeds
and if they do, what is the impact on the parks," said Sibdas Ghosh, chair
of Dominican's Department of Natural Sciences and Mathematics.
Colorado, Nevada and Montana require horse
owners to give their animals feed that has been certified as weed free.
A.
Preliminary Findings of DU of C:
The
preliminary study of forty five samples collected from selected locations
throughout the Northern California including
Bay Area and Central California were
transported to DU of C and placed in a refrigerator. Utilizing sterile
procedures, each bag was opened and split into two samples: one dry and one
wet. Samples to be dried were weighed and placed on paper towels and then
transferred on to paper plates. Whole sample was covered and placed on
counters to air dry. The remaining samples were placed back into
individual bags to maintain the original integrity of the horse manure.
Sterile gloves were used at each separation process to avoid cross
contamination. Gloves were then counted after procedure was complete to ensure
that all gloves were used only once.
After
one week, both dry and wet samples were weighed and planted individually in
sterile 4 inch pots containing weed free soil. Vinyl gloves were
used for each sample. Once samples were potted, they were randomly
numbered 1 through 45 for wet samples and 1A through 45A for dry
samples. A random number selection process for pot locations in trays was
computer generated along with 10 control samples which contained no horse
manure.
After
numbering and placing pots into trays, samples were covered and transported to
racks which were completely enclosed in a netted, potting shed located three
feet off ground. This prevented wind or animal based seed contaminations.
A self-timed watering system within the enclosure was used to evenly water the
samples. Plants were monitored daily for comment notes, growth, photos.
Of
ninety pots, 34 plants germinated in 21 pots of which 12 represent dry and 9
represents wet samples respectively. All plants were identified by Ms.
Doreen Smith, California Native Plant Society, Marin Chapter, CA. NONE of the
plants identified are listed as Noxious Weeds on the CDFA site. We report
that 2 toad rush (Juncus bufonius), 25 Italian ryegrass (Lolium multiflorum), 1
bur-clover (Medicago polymorpha), 1 summer mustard (Hirschfeldia incana), 1
cudweed (Gnaphalium luteoalbum), 1 purslane (Portulaca oleracea), 1 dooryard
knotweed (Polygonum aviculare), 2 cheeseweed (Malva niceaeensis). Only
toad rush (Juncus bufonius) is a native California
while the rest are non-native to USA. However we have found
that none of these plants are listed as CDFA (California Department of Food and
Agriculture) Noxious Weeds.
Currently
we have additional 90 horse manure samples collected mainly from the National
Parks of Northern California. We are in the process of daily monitoring
of plants species germinated from the samples. The anticipated identification
of these plant species will be completed by March 31, 2006.
Campbell,
J.E., Gibson, D.J. 2001. The effect of seeds of exotic species transported via
horse dung on vegetation along trail corridors. Plant Ecology 157(1): 23-25
Landsberg, J., Logan, B., Shorthouse, D. 2001. Horse riding in urban conservation
areas: Reviewing scientific evidence to guide management. Ecological Management
and Restoration. 2: 36-46.
Summary
We undertook a literature review of the
impacts of horse riding in conservation areas, and used it to guide management
of horse riding in Canberra Nature Park (CNP), a large, fragmented semi-natural
park in and around the city of Canberra
in the Australian Capital Territory.
The literature review established that, because of their relatively large
weight and small area in contact with the ground, horses have a relatively high
potential for doing environmental damage. Impacts tend to be generally lowest
for hikers, followed by motorcycles, horses and four-wheeled vehicles. One
study showed horse traffic caused more damage on established trails than
motorcycles, off-road bicycles or hikers. Most published studies of
horse-riding impacts in Australia
have been conducted in alpine and subalpine environments, and in temperate
woodlands and forests on sandstone near Sydney.
They have shown that impacts are generally highest in previously untracked
areas. Impacts on established trails are generally most marked on sections of
trail that are wet, boggy or steep, and on unplanned and unmaintained trails.
Impacts are lowest on constructed and maintained trails. Trail proliferation,
associated with avoidance of untrafficable sections and short-cutting, can be a
major problem. Horses also have potential to spread weeds, because pastures and
dried stock feeds contain large numbers of weed seeds that retain high levels
of viability in horse manure. The risk of weed establishment is highest when
manure is deposited in disturbed, damp sites, particularly when riding
off-track. Much less weed establishment is apparent when horse riders remain
on-track. Horse riding is a popular activity, but one that is relatively expensive
to provide for, and one that may reduce opportunities for lower-impact
recreational park users. For all these reasons it appears socially equitable
that provision is made for lower numbers of horse riders compared to numbers of
park users involved in lower impact, more passive, recreational activities. We
conclude by describing how this information was used to develop principles to
guide management of horse riding and assess risk at individual sites in Canberra Nature Park.
Harmon
GW and FD (1934) The percentage and viability of weed seeds recovered in the
feces of farm animals and their longevity when buried manure. Journal
American Society Agronomy. 26: 762-767
Soil
Compaction/Disturbance
Cole, D. N.; Spildie, D. R. 1998. Hiker, horse and llama
trampling effects on native vegetation in Montana, USA. Journal of
Environmental Management 53: 61-71.
Leopold Publication Number 332
Abstract:
Intensity of trampling disturbance varies with
type of recreation traffic. The purpose of this study was to assess the
relative impact of hiker, horse, and llama traffic on vegetation and
groundcover conditions. Hiker, horse, and llama traffic were applied at two
trampling intensities to two previously undisturbed forested vegetation types.
Trampling effects were assessed immediately after traffic application and 1
year later. For most impact parameters, intensity of trampling impact varied
with type of user. For all parameters that varied with type of user: (1) horse
traffic caused the most disturbance; and (2) hiker and llama impacts could not
be differentiated statistically. The forb-dominated vegetation type was highly
vulnerable to vegetation impact but recovered rapidly. The shrub-dominated type
was more resistant but lacked resilience. Higher trampling intensities caused
more disturbance but the relationship between trampling intensity and
disturbance intensity was non-linear.
DeLuca, T. H.;
Patterson, W. A., IV; Freimund, W. A.; Cole, D. N. 1998. Influence of llamas,
horses, and hikers on soil erosion from established recreation trails in
western Montana, USA. Environmental Management 22(2): 255-262
Leopold Publication Number 319
Abstract:
Various types of recreational traffic impact
hiking trails uniquely and cause different levels of trail degradation;
however, trailhead restrictions are applied similarly across all types of
packstock. The purpose of this study was to assess the relative physical impact
of hikers, llamas, and horses on recreational trails. Horse, llama, and hiker
traffic were applied to 56 separate plots on an existing trail at Lubrecht Experimental Forest
in western Montana.
The traffic was applied to plots at intensities of 250 and 1000 passes along
with a no-traffic control under both prewetted and dry trail conditions. Soil
erosion potential was assessed by sediment yield and runoff (using a Meeuwig
type rainfall simulator), changes in soil bulk density, and changes in soil
surface roughness. Soil moisture, slope, and rainfall intensity were recorded
as independent variables in order to evaluate the extent that they were held
constant by the experimental design. Horse traffic consistently made more
sediment available for erosion from trails than llama, hiker, or no traffic
when analyzed across wet and dry trail plots and high and low intensity traffic
plots. Although total runoff was not significantly affected by trail user, wet
trail traffic caused significantly greater runoff than dry trail traffic. Llama
traffic caused a significant
Soil
compaction comparison (in gm/sq.cm) of pedestrian, horses, bikes etc.
Eckert, R.E. Jr, Wood, M.K., Blackburn, W.H., & Petersen, F.F.. 1979. Impacts of
Off-Road
Vehicles on Infiltration &
Sediment Production of Two
Desert Soils. Journal of
Range
Management. Vol. 32. Pages
397-397.
Liddle, M. & Grieg-Smith.,
1975. A Survey of Tracks & Paths in a Sand Dune Ecosystem.
Journal of Applied Ecology
Vol. 12 Pages 909-930.
Liddle, M. & Scorgie, H.R.A.
1980. The Effects of Recreation on Freshwater Plants and
Animals: A Review. In Biological
Conservation 17.
Abstract
This
paper reviews the impacts of recreation on freshwater plants and animals. A
distinction is made between water- and shore-based activities, and between
physical and chemical effects. The impacts of water-based recreation, which
result mainly from boating, are discussed in terms of wash, turbulence and
turbidity, propeller action, direct contact, disturbance to animals, pollution
from outboard motors and sewage. Those resulting from shore-based activities,
such as angling and swimming, include trampling and associated effects, as well
as sewage and other chemical impacts. The effects of management for recreation
are also considered. There is relatively more information on the effects of
recreational activities on plants than on animals, but the authors consider
that further research is required in both fields. Some possible approaches are
presented.
Liddle, M., 1997. Recreation Ecology. Chapman & Hall, London.
Godwin, I.C.P. 2000. Physiographic
Components of Trail Erosion. M.S. Thesis, Montana State University, Bozeman MT.
Abstract
No previous study has sought to discriminate between soil
erosion and soil compaction when explaining the missing cross-sectional areas
of incised trails, assuming instead that erosion was the dominant process.
Separating the two processes of erosion and compaction is critical to
understanding the relationship between physiographic variables and the
structure of trails.
The purposes of this project are to estimate the relative
effects of compaction and erosion on trail cross sectional area along the New
World Gulch Trail, Montana, and to better understand the relationship between
erosion, compaction, local topography, vegetation, soil bulk density, and soil
texture. The following hypotheses were addressed: 1) adjusting the incised
cross sectional area of a trail, by removing the effects of soil compaction,
will increase the amount of variance in erosion explained by collected physiographic
variables; and 2) inclusion of soil bulk density and soil texture as physiographic
variables will increase the amount of variance in cross-sectional area explained
along the trail.
The goals of this study required the collection of field
data, analysis of soil samples, and statistical analysis of data. Soil samples
and other field measurements were collected over several months during the
summer and fall of 1994. Some of the topographic information used in the
statistical analysis originated in Urie's (1994) studyof recreational trails.
The determination of trail slope as one of the primary
components of trail incision is consistent with previous studies. Soil water
content is the second most significant independent variable when the percentage
of particle sizes are not considered. Percent vegetative cover is also
significant in the stepwise regression, although it is not significantly
correlated to cross-sectional area.
The most significant variable added to those already studied
was soil bulk density. When individual variables were regressed against the
measured cross-sectional area, off trail soil bulk density accounted for the
second greatest amount of variance (r2 = 0.12) after trail slope (r2 = 0.35).
The ratio of on-trail soil bulk density to off-trail soil bulk density, which
could be considered a measure of compaction, accounted for even more variance
(r2 = 0.18) than soil bulk density.
General Understanding of Dog
Impacts
Recommendations
and brief discussion of dog impacts. - Canada
Urban
problems with dogs and cats. Australia
Not the
exact article, but by the same author - Murray
Murray, R. W. and
Penridge, H. 1992. Dogs in the Urban Environment: a handbook of municipal
management, Chiron Media, Mackay.
Cameron, D. 1993. 'The impact on rural
production of irresponsibly owned pets', Proceedings of the UAM Integration
Symposium, November 1993.
Faecal litter management - a local government priority for
reasons of community health and environmental amenity. Virginia Jackson
Proceedings of the UAM Integration Symposium, 2000.
Abstract
Many local authorities around Australia have introduced laws that
require dog owners to pick up after their dog in public places. In New South Wales, this
requirement is contained in the Companion Animals' Act.
A range of products and facilities has been developed and
are in use around the world to address this issue. However the expense involved
can be extremely high and local authorities need to decide carefully whether
this is the best allocation of resources relative to other priorities. Virginia will outline
the results of recent research on the options available for removing dog
faeces. She will also report on a recent nationwide telephone survey that
sought to uncover the importance of unremoved dog faeces vis-a-vis other animal
management issues.
Dog Issues/Regulations at Other
Locations
Juneau Alaska
SanFrancisco
California
Australian
Urban Animal Management Proceedings 1992-2000
OffLeash1
- Australia
OffLeash2
Australia
OffLeash3
- Australia
Open space
for dogs Australia
Regulations
Australia
Dog bite data
Australia
Dog
bite data Colorado
About 116 reported bites/year in Colorado
over the last 10 years these are hospitalizations.
Dogs and Wildlife
Environmental
Impacts:The Dark Side of Outdoor Recreation. by Scott G. Miller
Dogs and Vegetation
Dog Issue in Boulder
Murphy
comments to Boulder City Council re: Mt. Sanitas
Letter to Boulder
City Council 2005.
I am a plant ecologist in Boulder Colorado. For years I have observed the accelerated
degradation of the local hiking trails due to off-leash dogs. Because of the powerful stigma against saying
anything negative about dogs, few studies exist that demonstrate even the most
obvious impacts of dogs. Those impacts
include compacted ground, poop and urine that create prime weed invasion sites
(we have had continuaous new weed invasions along the trails especially the
parallel dog trails that humans dont use), wildlife impacts (we have had deer
killed while hikers watched, I have observed that the towhee that was once
abundant is now uncommon, there are dog trail rings around the shrubs where the
birds used to be), Children have been mauled, and adults have been injured, and
the list goes on and on. I hope that a
conscerted effort is made to maintain the strict regulations until the studies
can be conducted that test/prove the obvious.
When dogs go off trail they accelerate the negative impacts of
recreation in a disproportionate rate. I
have had three dogs in my life an I love dogs.
Why must I continue to watch the degradation caused by dogs because
there is no science that proves the obvious.
If I had enough resources and was willing to sacrifice perfectly good
habitat I could easily prove that dogs have a negative impact that is not
necessary and not justified. Dog owners
can be fierce and will never accept the obvious even when the science does
exist, that is why you need to be conservative and protect the environment
until the science can be completed.
Please kick start the research that will demonstrate the
impacts of dogs. I know it is almost
sinfully wasteful to spend the money necessary to do this, since I feel that it
will only prove the obvious, but to let the slow/fast degradation continue is
far worse and far more costly in the long run.
Restoration is far more expensive that protection, and total loss is
tragic.
There is selfishness in the attitudes of many that say that
when it comes to public land, we own it, so we should be allowed to consume it,
and we have no significant impacts.
Don't let selfishness be the foundation upon which management is based.
Thank you.
