IUCN/SCC Otter Specialist Group Bulletin
©IUCN/SCC Otter Specialist Group
Volume 26 Issue 2 Pages 65 -
131 (October 2009)
Citation: Polechla, P.J. Jr. and Carrillo-Rubio,
E. (2009). Historic and Current Distributions of River
Otters (Lontra canadensis) and (Lontra
longicaudis) in the
Río Grande or Río Bravo del Norte Drainage of
Colorado and New Mexico, USA and of Chihuahua, Mexico and Adjacent
Areas. IUCN
Otter Spec. Group Bull. 26 (2): 82 – 96
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Historic and Current Distributions
of River Otters (Lontra canadensis) and (Lontra longicaudis)
in the Río Grande or Río Bravo del Norte Drainage
of Colorado and New Mexico, USA and of Chihuahua, Mexico and
Adjacent Areas
Paul J. Polechla Jr.1 and
Eduardo Carrillo-Rubio2,
1Department
of Biology, MSC03 2020, 1 University of New Mexico, Albuquerque,
NM 87131-0001 USA. E-mail:ppolechl@sevilleta.unm.edu
1Department of Natural
Resources, Fernow Hall, Cornell University, Ithaca, NY 14853 USA |
|
Abstract: The Río
Grande drainage is an important and imperiled wetland of the
US/Mexican border arid lands. There is a desire to restore otter
populations in this river by interested parties. In order to
follow IUCN guidelines for restoration, biologists need learn
more fully the situation prior to implementation of restoration
management. A prerequisite for proper restoration conservation
is to know the organism’s taxonomy (i.e., what taxa or
species and subspecies one is dealing with), distribution, and
relative abundance. The historic and current distribution of
the Nearctic otter (Lontra canadensis) and
Neotropical otter (L. longicaudis) in the borderlands
of US and Mexico are reviewed in this paper. The evidence indicates
that otters were native to the Río Grande valley and has
been recorded in the languages and customs of Native Americans
such as the Pueblo people prior to European settlement of the
area. The first Spanish documents we were able to find whereby
otters were recorded, date to the middle 16th century. Otters
during historical times were probably more numerous than previously
thought and one of the first wildlife laws in the borderlands
revolved around a moratorium on trapping the otter and beaver.
Presently, populations of otters occur in 1) the Río San
Pedro of Chihuahua, a tributary of the Río Conchos entering
the Río Grande from the southeast, 2) the upper Río
Grande near the Colorado/New Mexico border, and 3) the middle
Pecos River in southeastern New Mexico entering the Río
Grande from the west. These observations are corroborated
by multiple observations by competent observers and in the case
of the first population, otter photos and sign. These populations
are centered on areas with macro-habitats characterized by a
river flowing through 1) deep canyons, or 2) ancillary wetlands.
Considerable more detailed survey work is needed to determine
the full extent of the distribution of otters in the Río
Grande drainage. A genetic study is critically needed to determine
the true taxonomic affiliation of these recently discovered populations.
A moratorium on translocations should be put in place for the
Río Grande to conserve the native populations already
existing. |
Keywords:
Nearctic, Neotropical, river otter, Río Grande, Río
Bravo del Norte, Pecos River, Río Conchos, distribution,
historic, current, USA, Mexico, Colorado, New Mexico, Texas,
Chihuahua, Coahuila, Nuevo Leon, Tamaulipas, Spanish, Native
American, Pueblo, habitat, beaver, translocation, stocking, IUCN,
moratorium, genetics. |
Française | Español |
INTRODUCTION
In his later years when asked by a reporter about rumors of his death,
Samuel Clements or Mark Twain was quoted as saying (Paine
1912): “Just
say the report of my death has been grossly exaggerated.” The
same could be said about the river otter of the Río Grande or
Río Bravo del Norte except for one important distinction; Mark
Twain was a well-known author of the literary world, whereas the river
otter of the Río Grande is a veritably unknown animal in the
scientific world.
Various authors reviewing the mammalian species of a given geopolitical
area (i.e. country or state) have often neglected the otter. Granted,
writing the “mammals of” type book requires much diligence
to include detailed information such as the distribution for a specific
geopolitical area. This is especially true of areas like the borderlands
of the US and Mexico where there are extremes in altitude and climate
that produce a high floral and faunal diversity. The initial thought
of an otter, a semi-aquatic mammal, totally reliant on the close proximity
to open water, in the midst of a desert seems to be an enigma. Wildlife
biologists in the arid southwestern US and northern Mexico usually
study the desert, grassland, or alpine fauna. Be that as it
may, ignoring a semi-aquatic member of the native fauna of the priceless
wetlands of a sun-parched region is totally irresponsible. Add to the
difficulty of developing an accurate faunal list with the many languages
and cultures (e.g., English, Spanish, Diné, Pueblo, etc.) in
the region, plus the fact that a boundary bordering two countries (USA
and Mexico) and six states (New Mexico, Texas, Chihuahua, Coahuila,
Nuevo Leon, and Tamaulipas) is a river with tributaries on both sides
and this is a challenging situation prone to developing errors of omission.
Mark Twain is also credited for saying “Whiskey is for drinkin’;
water is for fightin’.” It surely applies to the endangered
waters of the American West. The Río Grande headwaters
in southern Colorado and then flows through the San Luis Valley, the
Taos Plateau of New Mexico, the middle Río Grande valley of
New Mexico, the Mesilla Valley, and the lower Río Grande and
along the Texas/Mexican border then out to the Gulf of Mexico between
the neighboring cities of Brownsville, Texas and Matamoros, Tamaulipas.
The Río Grande ranks as the longest river in Mexico, the eighth
longest in the US (US Geological Survey web site), ninth longest in
North America (with 52.1% in the USA and 47.9% in Mexico), and the
26th longest in the world (http://en.wikipedia.org/wiki/List_of_rivers_by_length visited
on 3 December 2007) with 3,057 km of waterways. The Río
Grande with all its drainages (e.g., Pecos River) ranks as the third
largest river system in the US and measures an estimated 4,386-4,547
km long.
In 1997 the US Environmental Protection Agency declared the Río
Grande to be an American Heritage River to further “natural resource
and environmental protection” (Clinton. 1997). Sections of the
river (and the tributaries including the Red River, Río Chama,
East Fork of the Jemez River, and Pecos River) in northern New Mexico
and west Texas have been classified as “Wild and Scenic Rivers” by
the federal government. American Rivers, a non-profit river advocacy
organization, ironically has declared the Río Grande and its
tributaries the Río Chama and the Santa Fe River, one of the
most threatened or endangered rivers in the US, eight times from the
period 1986-2007 (American Rivers, 2007). Furthermore in 1993, the
Río Grande topped the charts and in 2007 the Santa Fe River
was listed as the most endangered. The Santa Fe River is now a dry
ditch but once was a natural flowing stream in 1881. The Río
Costilla, a tributary on the east bank on the Colorado/New Mexico border,
is also dry most of the year (Polechla, 2000). The Río Grande
is truly endangered too since it only occasionally (e.g., 2000, 2001,
and 2006) reaches the Gulf of Mexico like it formerly did. Reasons
cited for its poor condition include intensive agriculture, overgrazing,
plus improper disposal of toxins, industrial pollution, domestic sewage,
and mine wastes. The Environmental Protection Agency
(2000) had proposed
a molybdenum mine on the Red River near Questa, NM as a “Superfund
Site” for cleanup of mine tailings. By far, the largest threat
to the Río Grande remains dewaterization.
New Mexico is the last state in the US to restore river otter populations
(Anonymous 2006). Since river otters in the Río Grande are regarded
as rare and their riverine habitat is also very endangered, this publication
summarizing the current situation with the river otter in the Río
Grande is very timely. This article is an attempt to correct this lack
of attention devoted to the river otter in this drainage. We will take
a historical as well as a contemporary examination of the evidence.
MATERIALS AND METHODS
We searched for records in English and Spanish at: 1) the special
collections at Center for Southwestern Research (CSWR) at the Zimmerman
Library at the University of New Mexico, Albuquerque, NM, 2) City of
Chihuahua Archives, CHIHUAHUA, México, and 3) antique maps at
the Map and Geographic Information Center (MAGIC) at the Centennial
Science and Engineering Library (CSEL), University of New Mexico for
place names with otters, and 4) books written on regional fauna of
the borderlands. Wherever possible, we read original primary sources.
We also surveyed sections of the Río Grande and its tributaries
ourselves (Figure 1). While conducting reconnaissance trips we interviewed
local people along the river and its tributaries about otters.
|
Figure
1. Spatial distribution of recent records of native river
otters (possibly Lontra canadensis lataxina) in the Rio Grande
watershed (upper Rio Grande =1; middle Pecos river =2; lower
Rio Grande Valley =3; upper Rio Conchos =4) and stocked populations
of the exotic L. c. pacifica subspecies in the Rio Pueblo de
Taos at > (S). (click for larger version) |
RESULTS AND DISCUSSION
USA
Colorado
American Period
Otters are known historically from the so-called San Luis Valley
or the upper Río Grande on the present-day New Mexico/Colorado
border (Coues, 1898). American explorers, such
as the phonetic speller Major Jacob Fowler trapped “bever” [sic
= beaver (Castor
canadensis)] and “aughter” [sic = otter] in 1822 in
the upper Río Grande drainage of present day Colorado. He was
an unusual trapper since he was educated enough to record his daily
catch in a journal and use a sextant and compass to pinpoint his location
all while enduring the rigors of outdoor life.
Twenty-first Century
At the southern part of Alamosa National Wildlife Refuge (ANWR), two wildlife
biologists, Kelli Stone and Kristina Crowder, made an interesting observation
while driving to check their mist nets. Kelli had been apart of the Green River,
Utah otter translocation program (she had seen adults and young at Ouray National
Wildlife Refuge, near Green River, Utah, and in a northern Rocky Mountain stream
as well). On 12 September 2001 at about 0630 Mountain Standard Time (MST),
both Kelli and Kristina saw an otter running across a sand bar close to the
far bank of the Río Grande (river width = 18.3 m) above La Jara Creek,
Alamosa County, Colorado. (mentioned briefly in Polechla
2002b, and recorded
fully in the field notes of Paul Polechla, 28 February 2002). It appeared “long,
thin, and dark” with its head and body about 76.2 – 91.4 cm long.
They saw the animal at a distance of 27.4 m for about 3-5 s duration. It had “an
S-shaped crimp” in it’s back displaying an up and down motion.
After there initial observations, it bounded onto the willow bank. It did not
resemble a mink (Neovison vison), weasel (Mustela frenata),
muskrat (Ondatra zibethicus), or beaver in size, shape, and movement.
One of Kelli and Kristina’s colleagues also saw one otter at 1900 MST
at the same site. We regard their sightings as highly credible ones due to
the precision and accuracy of their descriptions of the morphology and behavior
of animal they saw and the match with those of the river otter.
To date, no translocations of otters have been conducted into the Río
Grande (Polechla, 2002a). However, translocations of exotic otter subspecies
were placed in the Piedra River, Dolores River, Gunnison River at Black Canyon,
and headwaters of the Colorado River in Rocky Mountain National Park; all are
apart of the Colorado River drainage. Otters were also translocated to Cheesman
Reservoir along the South Platte (Polechla, 2002a,b; DePue
and Schnurr, 2004)
part of the Missouri/Mississippi River drainage.
Beaver and muskrat both occur at ANWR (Polechla, unpublished data)
and south into New Mexico (Polechla, 2000). Besides the river the
area has a myriad of abundant wetlands including: wet meadows, marshes,
oxbows, sloughs, canals, and small reservoirs.
New Mexico
Native American Period-Pre/Early European Contact
A photo in Dozier (1983) documents Santa Clara
Pueblo men wearing otter fur in braids in their hair. Hill
(1982) tells
of people from Santa Clara Pueblo wearing otter fur headbands and
collars. Bailey (1931) described the Native American knowledge about
the otter along the Río Grande. “The Taos Indians are
familiar with them, and bits of fur were seen on their clothing and
ornaments as well…” He added that the Taos Pueblo people
not only utilized their skins but also had a unique name in their
Tewa language for the otter. An otter effigy pot was excavated from
Pecos Pueblo on Arroyo del Pueblo, a tributary of Glorieta Creek,
a tributary of the upper Pecos River located about 4 km South and
0.8 km East of the village of Pecos, New Mexico (Polechla
2000, Kidder
1932). This site was estimated to be between 1200 and 1838 AD.
Spanish Colonial Period
In 1541, Hernando de Alvarado commented that the “Río Pecos” or
Pecos River “contains very good trout and otters” (Hodge,
1946).
Nicolas de Lafora (Weber, 1971) wrote about the Río Grande in 1767 commenting
that New Mexicans “pay no attention to otter, beaver, ermines, and martin
[sic marten] skins, which they have in abundance, because they do not know their
value.” Fray Morfi (1782 fide Rea 1947) records beaver and otter on the
Río Grande in 1782.
The place called “Las Nutrias” along the “Camino Real” was
named in Spanish after ‘the otters’ and dates back to 1682 (Rivera
and Humboldt, 1807; Julyan, 1998, Polechla,
2000; LoPopolo, 2006; Carlos LoPopolo,
personal communication). This village is located at 34.477 degrees N.106.770
degrees West Longitude on the east bank of the Río Grande in present-day
Socorro County, NM.
There are a number of other place names with nutrias or otters for localities
in New Mexico (Pearce, 1965; Julyan,
1998; Topozone.com) and Colorado (Polechla,
2002a). Often times place names with otter or nutria refer to an abundance
of otters in this region historically (Polechla, 2002c).
The officials in City of Chihuahua, fearing over-trapping of beaver and otter
in the Río Grande, closed the river to trapping these two species (Weber,
1971) publishing the declaration in the official newspaper “El Noticioso
de Chihuahua” in 1838 (Polechla et al., in
prep). This indicates a greater
original abundance than was previously thought by authors such as Bailey
(1931) and Findley et al. (1975).
Early American Period
The military expedition known as the “Army of the West” led
by Lieutenant Colonel W. H. Emory guarded the Mormon Battalion from
Fort Leavenworth, Kansas to San Diego in present day California (Emory,
1848). They came via the Santa Fe Trail’s Mountain Route, passed
from later-day Raton to Santa Fe, NM then to the Río Grande
(on a main trail called the Camino Real) as far south as the Fra Cristobal
Mountains and then exited the Río Grande valley west across
the mountain gap now known as Emory Pass (Julyan,
1998), present-day
NM. On 11 October 1846, Captain A. R. Johnston of the expedition wrote
the following about the east bank of Río Del Norte at the base
of Fra Cristobal Mountains (Emory, 1848). “In passing the river,
I saw the tracks of the otter, the catamount, the wildcat, the bear,
the raccoon, the crane, the duck, the plover, the deer, and the California
[sic probably Gambel’s] quail.” Emory, the namesake of
the Emory oak (Quercus emoryi), summarized the observations
of others in the Mormon Battalion expedition by writing “…for
here we saw for the first time in New Mexico, any considerable “ signs” of
game in the tracks of the bear, the deer, and the beaver. We flushed
several bevies of the blue quail, saw a flock of wild geese, summer
ducks, the avocet, and crows.” It must be noted that the area
north of this region along the “Camino Real” contained
numerous human settlements, which had over harvested the wildlife along
the Río Grande. Just north of Tome, Johnston wrote about the
otter’s commensal partner, the beaver. “Above this camp,
there is on the river a considerable growth of cotton-wood, among which
are found some ‘signs’ of beaver.”
Other observations are known from the upper Río Grande. A “Mr.
Dowell” said that otter were found near the junction of the El
Rito de los Frijoles and the Río Grande between 1910-1911 (Henderson
and Harrington, 1914). The junction of these two waters lies
within present-day Bandelier National Monument, Sandoval County,
NM. Bailey
(1931) cited otter records from the upper Río Grande on the
following localities: “near Espanola, Rinconada, and Cienequilla.” “Cienequilla” or “Cieneguilla”,
meaning small marsh in Spanish, is now known as Pilar, Taos County,
NM (Julyan, 1998).
Bailey (1931) readily admits the conundrum
of not having specimens to properly decide which taxa he is dealing. Writing
about trappers' records of the 1820’s for the Gila River of southwestern
New Mexico in the Colorado River basin he says. “These records
undoubtedly refer to the typical Arizona form [L c. sonora],
but no more records are available in New Mexico except for the upper
Río
Grande and Canadian Rivers in the northeastern part of the state, where
the species is probably different. There is, however, not a specimen
from the State available for study and comparison, and until specimens
are obtained, no definite decision can be arrived at in regard to the
subspecies.” Findley et al. (1975) merely cites Bailey
(1931) and the record of McClellan
(1954) in the Gila River (1 mile [1.6 km]
S Cliff, Grant County) and adds “the species may well be extinct
in the state.” Findley et al. (1975) do
not indicate if any effort was made to survey for otters. They do not
hazard a guess as to what subspecies might be in the Río Grande
or Colorado, or Canadian River drainages of the state.
Modern Period
San Luis Valley
In the 1970’s, Dean Swift saw three to four otters at Eastdale
Reservoir (part of the Río Costilla drainage which winds its
way across the Colorado/New Mexico border and flows into the Río
Grande’s east bank (Polechla, 2000)).
At the mouth of the Río
Costilla, Jim and Peggy Swayback of MacKintosh, NM saw an otter (Polechla,
2000).
Taos Gorge
Dan Wood and Richard Spiegel of Bureau of Land Management (BLM)
were rafting the Río Grande when they saw an otter about 11.7
km S of the Colorado/New Mexico state line (Stahlecker
1986). Doug
Scott Murphy, a pioneer river outfitter on the upper Río Grande
and artist, claims to have seen a river otter at “Razorblades” about
3.2 km upstream of Sheep’s Crossing in 1997 (Polechla,
2000).
Todd Bates who lives on the Río Fernando de Taos (a tributary
on the Río Grande’s east bank) claims to have seen an
otter at the Sunshine Valley section of the Río Grande (Polechla,
2000).
Red River
Red River is a tributary on the east bank of the upper Río
Grande in New Mexico. A New Mexico Environmental Improvement Division
employee on the Red River at Columbine Canyon believed they saw
an otter in 1999 (Polechla, 2000).
Pecos River
Bitter Lake National Wildlife Refuge (BLNWR), Chaves County,
New Mexico lies on the Pecos River and has been a locality for
several otter observations (Polechla,
in prep. and 2002b, not
cited by Anonymous, 2006). The refuge is
characterized by a myriad of different wetlands next to the river
including: springs seeps, oxbow lakes, marshes, saline lakes,
karst sinkholes, shallow reservoirs, and canals.
The US Department of Interior, Fish and Wildlife Service reported
some sightings at BLNWR (Polechla
2002b). One of their
reports (USDI F&WS 1994) states the following. “A
river otter (Lutra [=Lontra] canadensis)
was reported by a visitor on Unit 6 reservoir in early May [1994].
An otter has never been documented on the refuge, and seems highly
unlikely. However, William R. Radke (refuge manager) found mammal
prints along the Pecos River in October 1993, which he believed
to possibly belong to a river otter. In addition, a fire crew dispatched
from Washington State to aid the refuge during the summer fire
season reported seeing a river otter at Unit 15 reservoir. None
of these sightings were ever confirmed.” On 25 April 1999,
Judy Dane, a volunteer coordinator with the New Mexico Museum
of Natural History saw what she believes to have been an otter
on the N end of Unit 6 impoundment of BLNWR (Radke,
1999, Judy
Dane personal communication to Paul Polechla, 22 June 2004).
This location is on the west side of the refuge and is close
to the Pecos River. Judy is a long time birder and has seen lots
of different species of wildlife on ecotours. She was standing
on the road bird watching in the late afternoon when at a distance
of 91.4 – 183 m, with the aid of her binoculars; she caught
a quick glimpse of an otter. By the “dark color, long dark
tail, size, and way it ran…humping its back and not waddling” she
assured me it was a river otter and contends it was not a muskrat
or a beaver. It was “bounding the weeds at the edge of
the water”. Furthermore she says, “I’ve
seen sea and river otters in Alaska... and beaver and muskrat
in New Mexico and the Eastern US” Her description/observation
is consistent with otter appearance and behavior and seems very
credible. Shy of an actual photo or track cast, etc. this observation
demonstrates the occurrence of river otter here.
Texas
Since the early province of Chihuahua included some of present
day west Texas along the Río Grande, the above-mentioned decree
in the 1838 “El
Noticioso de Chihuahua” also places otter in this part of the state (Polechla
et al., in prep). In their “Mammals of North America”, Hall
and Kelson (1959) do not have a Texas Río Grande location but do
provide a central Texas distribution record on the Colorado River near Austin,
citing
Bailey, 1905. In the next addition of “Mammals of North America”,
Hall (1981) shows the Brownsville, Cameron County, Texas location. This is
based on an actual otter specimen that Van Zyll de Jong (1972) listed and measured
and statically compared to other Lontra specimens including L.
canadensis and L. longicaudis. Van Zyll de Jong identified the
specimen as L. canadensis lataxina. Brownsville lies at the mouth
of the Río Grande across the river from Matamoras, Tamaulipas, Mexico. Davis
and Schmidly (1994) also showed the Río Grande locality but provided
no further information. Earlier versions of this work (Davis
1966, 1974) do
not show this locality. Polechla (1988, 1990) cites Hall
(1981) and Polechla
(1990) adds the rest of the Río Grande based on Weber
(1971). Polechla
(2000, 2002b) and Gallo (1986, 1989) cite this distribution locality in Cameron
County, along the Río Grande (plus one at the mouth of Colorado River).
Mexico
Harris (1968, p. 212) lists the type locality of the
Neotropical otter of México (Lontra longicaudis annectens) Major,
1897 as Terro Tepic, Río de Tepic, Nayarit, Mexico and shows the
trans-Madrean distribution making a slight “U” shape along
the Pacific coast from the Sierra Madre del Sur to a point about even
on the Mexican mainland with the tip of Baja California and on the
Atlantic side of the Gulf of Mexico to Tamaulipas, Mexico (including
an unnamed coastal river). Harris (1968) does not mention the Río
Grande nor is it mapped for distribution for the Nearctic otter of
the Southeastern US (L. c. texensis (now a synonym for L.
c. lataxina)). New Mexico is listed as part of range of L.
c. sonora and the upper part of Río Grande, Pecos, and
Arkansas Rivers (in state of Colorado) shown on the distribution map.
No individual records are shown on any of Harris’s maps however.
Chihuahua
The aforementioned decree in the 1838 “El Noticioso” for
Chihuahua closing the Río Grande to trapping beaver and otter
constitutes one of the first wildlife laws in the state of Chihuahua
(Polechla et al., in prep). Now otter populations are known from other
parts of the Río Grande drainage and western Chihuahua near
the border with Sonora and Sinaloa.
“West”-Central Chihuahua- Río San Pedro,
Río Conchos-Río Bravo Del Norte/Río Grande Drainage.
This region lies on the eastern slope of the Sierra Madre Occidental
of Mexico and has only been recently examined for otters. Carrillo-Rubio
and Lafón
(2004) published on the habitat of the otter in west-central Chihuahua, Mexico.
They found otter scats and tracks plus even took a photograph that the second
author (ECR) showed in a slide show at the 2004 IUCN Otter Specialist Group Colloquium
(Carrillo-Rubio et al., 2004). They emphasized the microhabitat
selection characterizing both the occupied and available habitat. Although this
is an essential aspect of otter biology and conservation, there was an even greater
significance of their work that was not mentioned. They had found otters where
no other scientist had reported them before! Gallo (1986, 1989), Lariviere
(1999), and even Gallo
and Casariego (2005) do not show the west-central Chihuahuan population
just the Chihuahuan/Sonoran border population described in detail in the next
section. The previous population that other biologists had described was in extreme
western Chihuahua near the Sonoran border on the west side of the Continental
Divide running down the Sierra Madre Occidental. The population in west-central
Chihuahua is totally new to science. Furthermore to date, this “new” population
is 1) the only one on the east side of the Sierra Madre Occidental, 2) the eastern
most population in Chihuahua, and 3) the northeastern most otter (Lontra spp.)
population in México.
Not only that but, the species of river otter (Lontra sp.) that they
are actually dealing with is not well understood. Recall that the arid US/Mexico
borderlands are the regions where both the Nearctic otter of the north meets
the Neotropical otter of the south. Prior to translocations (of different subspecies
from other drainages) by the US states of Colorado, Arizona, and Utah, only the
southwestern subspecies of the Nearctic river otter (L. canadensis sonora)
occurred in the Colorado River (Polechla and Walker
2008). When Bailey (1931) wrote his “Mammals of New Mexico”, he summarized a few reports of
otters on the Río Grande. It is unknown whether he searched for them himself,
but he probably was occupied investigating the diversity of mammals since the
state ranks very high in diversity ranking with California and Texas (Caire
1978).
The situation is further complicated since he did not have a specimen from the
state but knew full well that they have long been a part of the native fauna.
Without a specimen and knowing that the next drainage to the arid west was the
Colorado River, he assigned the otters in the entire state; including the Gila,
San Francisco, and San Juan River drainages, plus the Río Grande drainage,
and the Canadian River drainages, to that of the southwestern subspecies based
on geographical proximity.
Carrillo-Rubio and Lafon (2004) and Carrillo-Rubio
et al. (2004) working in Mexico
where the most-abundant otter is the Neotropical otter, assumed that the otter
in Chihuahua must be the Neotropical otter. They were not aware of L. canadensis
lataxina from the mouth of the Rio Grande at Brownsville, Texa that Van
Zyll de Jong (1972) examined and identified. Since they worked in the Río
San Pedro, which flows into the Río Conchos a tributary of the Río
Grande, this might not be the case. Since both Carrillo-Rubio and his associates
and Bailey knew of otters in the Río Grande but had no skin/skull specimens
to examine for identifying characteristics (Polechla,
Gallo, Tovar 1987), the
true identity awaits further study to determine if it is the Nearctic, Neotropical,
or an undescribed species or subspecies. Much study is needed to learn about
this newly discovered population. It should be conserved at all costs.
Chihuahua/Sonora/ Sinaloa Border
This area of Mexico is on the western slope of the Sierra Madre Occidental and
drains into the Sea of Cortez (i.e. Gulf of California) and ultimately into
the Pacific Ocean. Indigenous people are well aware of the Neotropical
otter of this region. The Tarahumara and northern Tepehuan people in the Río
Verde and Río Mayo of Chihuahua were familiar with the otter, using
their meat for food, fat for folk medicine, and skin for a sleeping mat (Sturtevant,
1983).
In 1904, Carl Lumholtz’s (1973) discovered “tracks of many raccoons
and otters…” along the Barranca de San Carlos that drains into the
Río Fuerte west of Nogal, Sinaloa, Mexico. Since Lumholtz’ observations,
the distribution of the Neotropical otter known to science has been moving northward
along the west side of the Sierra Madre Occidental. This is largely attributed
to an increase in mammalogical studies in northern Mexico associated with specimens,
photographs, and sightings of otters.
Leopold (1959) provides records on the Río Gavilán. Cockrum
(1964) reported on a specimen trapped from the Río Mayo near San Bernardo, in
southeastern Sonora in spring of 1963. Anderson (1972) cited two specimens from
northwestern Chihuahua from the Río Tutuaca, 20 km S Yaguarachie. In the
same general region of the state of Chihuahua, Anderson (1972) also gives records
for the Río Papigohi about 40 km down river from Temosahi. Roth
and Cockrum (1976) reported on a specimen from the Río Mayo at Alamos from 1965 plus
further to the north, another one at Los Pilares, 7 miles E [= 11.3 Km] of Yecora,
on the Río Mulatos, a tributary of the Río Yaqui. Caire
(1978) cites Roth and Cockrum (1976) and Anderson
(1972) and states that native people
at Tres Ríos on the Río Negro told him “that otters have
occurred there occasionally”. Brown et al. (1982) photographed three otters
in the Río Yaqui, Sonora about 3 km downstream of the Río Chico
confluence. The Río Yaqui flows into the Gulf of California between Guaymas
and Ciudad Obregon, Sonora, Mexico.
Along the Río Bavispe east of Tres Ríos Mesa in the Sierra Occidental
in Chihuahua, Johnson (2005) cites a Brian [Long] and Alan [last name unknown]
searching for otters. Johnson is probably referring to the reconnaissance trip
planned by Brian Long (2001, personal communication, 2001) of which no published
reports have been produced from this trip. To date, this region may constitute
the northern-most distribution of the Neotropical otter but lies on the west
side of the Continental Divide and is not in the Río Grande drainage.
Coahuila/Nuevo Leon/Tamaulipas Border
Río Salado
These river headwaters on the eastern side of the Sierra Madre Oriental
flow into the Río Grande on the Mexican side. The Río
Salado, a Río Grande tributary in eastern Coahuila, northern
Nuevo Leon, and northern Tamaulipas remains unsurveyed for otter, although Villa (1954) surveyed the river for beaver only. Bernal
(1978) later
surveyed beaver in this drainage in the state of Nuevo Leon.
Tamaulipas
The rivers in this region south of the mouth of the Río Grande,
headwaters on the eastern side of the Sierra Madre Oriental and flow
(albeit now irregularly) directly into the Gulf of Mexico and finally
into the Atlantic Ocean. Gallo-Reynoso
(1997) gave the following record in his review of Neotropical otter in Mexico. “Río
El Salado, afluente del Río Conchos, 2 km O de Paso Hondo (Mpio. De San
Fernándo, 50 m). Se revisó la piel de un individuo macho. Este
registro constituye el más norteño de la nutria neotropical en
la vertiente del Golfo de México (N).” This is translated as follows. “The
river ‘El Salado’, a tributary of the ‘Río Conchos,
2 km west of Paso Hondo (Municipality of San Fernado, 50 m)’. I examined
the pelt of an individual male. This constitutes the most northern record of
the Neotropical otter on the coast of the Gulf of Mexico.” This location
is about 425 km south of the mouth of the Río Grande.
CONCLUSION
In 1541, Spanish explorer Hernando de Alvarado is credited as the
first person to observe otters in the Río Grande drainage and
to write about his observation. Native American tribal knowledge of
otters probably predates the Spanish record. Analysis of the early
historical documents indicates that otters have been recorded in the
Río Grande from the 16th through the 21st centuries. One archaeological
record for an otter effigy pot was found in deposits dated from the
13th to the 19th centuries. Like the Arkansas (Polechla,
1987) and
the Colorado (Polechla, 2002b) Rivers, the historical distribution
of otters was from the headwaters to the mouth.
Unregulated fur trapping on Río Grande beavers and otters began
in earnest in the Mexican Period and continued through the American
Period. Undeniably there are at least three localities in the Río
Grande where otters are currently known to occur (Figure
1): 1) the
Río San Pedro in Chihuahua 2) in the upper Río Grande
around ANWR near the New Mexican border, and 3) the Pecos River at
BLNWR. Reports have come from competent biologists and naturalists
with previous experience with otters. At this time, the most extensive
population seems to be located in the Río San Pedro in Chihuahua
that is about 106.9 km from the closest population near the Chihuahuan/Sonoran
border on the other side of the Continental Divide. The habitat of
the first locality is where a river passes through a deep canyon and
the second and third localities are situations in which rivers flow
by small reservoirs, ponds, oxbow lakes, and springs. The deep canyons
might restrict some human visitation and development. Having a number
of wetlands juxtapositioned near each other is ideal for otter foraging
and traveling behavior. Very little of the Río Grande drainage
has been sufficiently examined however, with only 292.8 km to date
(Polechla, 2000; Carrillo-Rubio
and Lafón, 2004; Polechla, unpubl.
data), representing only 6.4-6.6 % of the total km of river ways in
the Río Grande drainage. The newest discovery of otters in the
Río Conchos necessitates that examination of the other tributaries
as well as the Río Grande per se, must be surveyed. The specific
designation of these otter populations, let alone the subspecific designation,
are unclear and await further study.
Management Implications and Recommendations
Mark Twain’s famous pun is applicable (Gore,
2006). “Denial
ain’t just a river in Egypt.” Contrary to the prevailing
opinion, native populations of river otters are present in the Río
Grande drainage. Governmental agencies denial of this fact and refusal
to protect them needs to be corrected. Currently, five river otters
(L. c. pacifica) from the state of Washington were unscientifically
stocked (Seattle Post-Intelligencer, 2008) into a river drainage that
undeniably already has a native otter. The “New Mexico
Friends of the River Otters”, the group responsible for the action,
has plans to stock more foreign Washington (Seattle
Post-Intelligencer, 2008) and Oregon (Associated
Press, 2007) otters into New Mexico. This
threatens an existing native population of river otters, currently
imperiled. The five stocked otters need to be live-captured and returned
to Washington. A genetic study is needed to elucidate the taxonomic
relationship of the otters of the US/Mexico border. Experienced otter
trackers need to conduct additional surveys to determine the distribution
of otters of the Rio Grande and borderland region in general (e.g.
Colorado River drainage to the west and the Canadian River drainage
to the east).
AKNOWLEDGEMENTS: We would like to
thank the following agencies for their support: Colorado Ocean Journey,
BLM, Theodore Roosevelt Fund, US Fish and Wildlife Service, Map and
Geographic Information Center, and the Center for Southwest Research.
Special thanks goes to Nancy Brown-Martinez and Mary Wyant for their
expertise.
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Résumé : Repartition
Actuelle et Historique des Loutres Lontra canadensis et Lontra
longicaudis sur le Rio Grande et le Rio Bravo du Nord du Colorado
et du Nouveau Mexique, USA, et Chihuahua, Mexique et Regions Adjacentes
Le réseau hydrographique du Rio Grande est une importante
zone humide des aires arides proches des Etats-Unis et du Mexique
mais elle est à ce jour largement en péril. Il existe
actuellement un désir de restauration des populations de loutres
sur cette rivière. Afin de suivre les lignes directrices de
l'UICN sur la restauration des populations, les biologistes doivent
avant tout évaluer la situation avant d'engager une gestion
favorisant le retour des loutres. La première nécessité est
de connaitre les espèces présentes, leur distribution
et leur abondance relative. Ainsi, les données historiques
et les répartitions actuelles de la Loutre de rivière
(Lontra Canadensis) et de la Loutre néotropicale
(L. longicaudis) sur les zones limitrophes des Etats-Unis
et du Mexique sont synthétisées dans cet article. Les
indices indiquent que les loutres sont originaires de la vallée
du Rio Grande et ont même été enregistrées
dans les langages et les décorations des indiens d'Amérique
tel que le peuple "Pueblo", et ce avant l'installation
des européens. En effet, le premier document espagnol que
nous ayons pu trouver mentionnant la Loutre date du milieu du 16ème
siècle. Par le passé, les loutres étaient sans
doute plus nombreuses que ce que nous pensons et l'une des premières
lois sur la vie sauvage dans cette région tournait autour
d'un moratoire sur le piégeage de la Loutre et du Castor.
Aujourd'hui, les loutres sont présentes sur :
1) le Rio San Pedro du Chihuahua, un affluent du Rio Conchos qui se jette dans
le Rio Grande par le sud-est,
2) la partie amont du Rio Grande près de la frontière du Colorado
et du Nouveau Mexique,
3) la partie centrale de la Rivière "Picos" dans le sud-est
du Nouveau Mexique qui se jette dans le Rio Grande par l'ouest.
Ces données résultent de multiples observations par des naturalistes
compétents mais aussi par des photos de loutres et des indices de présence.
Ces diverses populations fréquentent des aires dont les macro-habitats
sont caractérisés par des rivières à courants rapides à travers
des canyons profonds ou des zones humides secondaires. A vrai dire, des enquêtes
de terrain plus détaillées seraient nécessaires pour affiner
la distribution des loutres sur l'ensemble du système hydrographique du
Rio Grande. Par ailleurs, une étude génétique est absolument
indispensable afin de déterminer les distances génétiques
entre ces populations récemment découvertes. Enfin, un moratoire
sur les translocations pourrait être instauré sur le Rio Grande
afin d'assurer la conservation de ses populations.
Revenez au dessus
Resumen: Distribucion
Historica y Actual de los Nutrias del Rio (Lontra canadensis, Lontra longicaudis) en la
Cuenca del Rio Grande o Rio Bravo del Norte en Colorado y Nuevo Mexico,
E.U.A., Chihuahua, Mexico, y otras Areas Adyacentes
Le réseau hydrographique du Rio Grande est une importante
zone humide des aires arides proches des Etats-Unis et du Mexique
mais elle est à ce jour largement en péril. Il existe
actuellement un désir de restauration des populations de loutres
sur cette rivière. Afin de suivre les lignes directrices de
l'UICN sur la restauration des populations, les biologistes doivent
avant tout évaluer la situation avant d'engager une gestion
favorisant le retour des loutres. La première nécessité est
de connaitre les espèces présentes, leur distribution
et leur abondance relative. Ainsi, les données historiques
et les répartitions actuelles de la Loutre de rivière
(Lontra Canadensis) et de la Loutre néotropicale
(L. longicaudis) sur les zones limitrophes des Etats-Unis
et du Mexique sont synthétisées dans cet article. Les
indices indiquent que les loutres sont originaires de la vallée
du Rio Grande et ont même été enregistrées
dans les langages et les décorations des indiens d'Amérique
tel que le peuple "Pueblo", et ce avant l'installation
des européens. En effet, le premier document espagnol que
nous ayons pu trouver mentionnant la Loutre date du milieu du 16ème
siècle. Par le passé, les loutres étaient sans
doute plus nombreuses que ce que nous pensons et l'une des premières
lois sur la vie sauvage dans cette région tournait autour
d'un moratoire sur le piégeage de la Loutre et du Castor.
Aujourd'hui, les loutres sont présentes sur :
1) le Rio San Pedro du Chihuahua, un affluent du Rio Conchos qui se jette dans
le Rio Grande par le sud-est,
2) la partie amont du Rio Grande près de la frontière du Colorado
et du Nouveau Mexique,
3) la partie centrale de la Rivière "Picos" dans le sud-est
du Nouveau Mexique qui se jette dans le Rio Grande par l'ouest.
Ces données résultent de multiples observations par des naturalistes
compétents mais aussi par des photos de loutres et des indices de présence.
Ces diverses populations fréquentent des aires dont les macro-habitats
sont caractérisés par des rivières à courants rapides à travers
des canyons profonds ou des zones humides secondaires. A vrai dire, des enquêtes
de terrain plus détaillées seraient nécessaires pour affiner
la distribution des loutres sur l'ensemble du système hydrographique du
Rio Grande. Par ailleurs, une étude génétique est absolument
indispensable afin de déterminer les distances génétiques
entre ces populations récemment découvertes. Enfin, un moratoire
sur les translocations pourrait être instauré sur le Rio Grande
afin d'assurer la conservation de ses populations.
Vuelva a la tapa
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