Four of five pinyon-juniper tree species declining in their ranges in the West
https://sciencespies.com/nature/four-of-five-pinyon-juniper-tree-species-declining-in-their-ranges-in-the-west/
Four of five pinyon-juniper tree species declining in their ranges in the West
Pinyon-juniper woodlands host unique wildlife and wildlife habitat, as well as areas for hiking and outdoor recreation. They are also part of a web of healthy ecosystems that, together, help to balance water availability, storage and runoff; and prevent erosion. A new study published in Global Ecology and Biogeography and led by University of Nevada, Reno researcher Robert Shriver sheds new light on what is happening in pinyon-juniper woodlands across the West. The research is unique, in that it looks at both tree mortality, as well as recruitment, or new seedlings and saplings, to calculate a “net effect.” And, the news isn’t necessarily good, particularly in warmer, drier locations.
“We found that four of the five species were declining,” said Shriver, an assistant professor in the University’s College of Agriculture, Biotechnology & Natural Resources. “And, in the driest, warmest locations, up to about 50% of populations are declining. It’s pretty severe in those locations, which are usually at lower elevations that tend to be hotter and get less water than woodlands at higher elevations.”
Shriver said that when looking at all locations studied, which included over 6,000 plots and more than 59,000 tagged trees, up to 10-20% of populations were declining. Of the five species, including two pinyon pines and three junipers, Pinus edulis, more commonly referred to as two-needle pinyon or simply pinyon, showed the greatest declines, with about 24% of its populations in decline. The other pinyon species and two of the juniper species showed more moderate declines overall, but still quite severe declines in the hotter, drier areas. These species include Pinus monophylla (single-leaf pinyon), Juniperus monosperma (one-seed juniper) and Juniperus scopulorum (Rocky Mountain juniper). Juniperus osteosperma (Utah juniper) was the only species that did not show a decline.
“Utah juniper was the exception to everything,” Shriver, who conducts research as part of the College’s Department of Natural Resources & Environmental Science and Experiment Station, said. “What we found pretty much matches up with what we know about that species’ resiliency. It’s the most abundant in the Great Basin, and is typically less vulnerable to hotter, drier climate conditions, so it could mean that there might be compositional shifts occurring in the future, where some areas that are mixed species might become more juniper-dominated.”
Gathering the data and building the models
In part, Shriver used data from the Forest Inventory and Analysis, a nationwide survey of forested lands in the U.S., conducted by the U.S. Forest Service.
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“They tag the trees and return to the same plots for comparison at least every 10 years, but they have a systematic scheme to determine where,” he explained. “They are making sure they are getting a broad sample of both federal and private land. The result is a representative sample of what all forests look like across the U.S., even covering some very remote locations. It’s staggered, with 10% of plots surveyed in a given year.”
Shriver said the plots that were included in this pinyon-juniper research were first sampled between 2000 and 2007, and were surveyed the second time between 2010 and 2017. It is data obtained within those 10-year spans that he used for the research. He pointed out, however, that the Forest Service survey doesn’t capture as complete data on recruitment, or seedlings, since they don’t tag anything under 1 inch in diameter. Trees of this size are counted, but not tagged.
“Recruitment is the really hard part,” he said. “Tree mortality is easy to see, but recruitment is harder to observe, so it’s been harder to account for. Having a stable population is dependent on both mortality and recruitment. So, we developed a new statistical approach that allowed us to understand and factor in recruitment. Using these modeling approaches, we were able to quantify what the recruitment rate is in these different areas, and then combine that data with the mortality data to get a more clear, accurate picture of what is really going on in terms of change in species’ populations under different climate conditions and woodland densities in different regions.”
The research excluded plots where fire mortality or intentional tree harvesting occurred, allowing the researchers to more directly observe changes occurring due to climatic conditions across each species’ range.
Impacts of the findings
Shriver says the declines in populations they calculated could be significant for a number of reasons.
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“In regard to wildlife, probably the most significant effect is on the pinyon jay, which has been in decline for the last couple of decades, and is really dependent on the seed that is produced by pinyon pine,” he said. “The areas where the pinyon jay tends to choose are on that border of the sagebrush and the pinyon. It likes those habitats that are probably the most vulnerable. But, beyond the pinyon jay, certainly a number of species could be affected — mule deer, and other birds and wildlife.”
In addition, Shriver said pinyons and pine nut harvesting are culturally important, to Native Americans and others, and pinyon-juniper woodlands provide recreational value for hikers and outdoor enthusiasts. Importantly, he adds, there’s the functions that pinyon-juniper woodlands play in our watersheds. Pinyon-juniper woodlands play an important role in water and soil retention in some locations.
What does the future hold?
“We are likely to see pretty big changes in where we find forests in the Great Basin and the Southwest over the next few decades,” Shriver said. “A lot of places where we saw forests, we may not see them, especially in lower elevations, because they tend to be the hottest and driest.”
Shriver said there has been a lot of expansion in these woodlands since the mid-1800s, and that some declines may not be a bad thing everywhere. For example, in some areas the pinyon-juniper woodlands have encroached on shrubland ecosystems that provide important ecosystem services and unique wildlife habitat. And, the trees, especially when packed in too densely and without enough moisture, also increase the intensity of wildfires.
“Our results also suggest that for some locations, management actions could slow down or reverse the woodland declines,” Shriver said. “As it gets warmer and drier, the density of trees a landscape is able to support lessens, so reductions in tree density might expand the envelope of where the trees can be, reducing the chance of large tree mortality events.”
While woodland decline could create an opportunity for expansion of native shrublands such as sagebrush, Shriver cautioned that other, less beneficial vegetation could also take hold.
“Just because the pinyon and juniper die off, doesn’t mean something desirable would establish in their place,” he said. “You might get cheatgrass or other undesirable vegetation.”
Shriver said the purpose of the research and models it created is to help anticipate the vulnerability of woodlands and forecast coming range shifts, so that we might be able to sway the outcomes to be more positive ones.
“If we know where this is likely to happen, we can do the best we can to influence what might happen next,” he said. “We might be able to direct these into ecosystems that might support native plants and animals in the Great Basin and the Southwest, and fit into our watersheds in a beneficial way.”
Funding for the study was provided by the United States Geological Survey North Central Climate Adaptation Science Center. Coauthors of the study include Charles B. Yackulic and John B. Bradford, with the USGS Southwest Biological Science Center; and David M. Bell, with the USDA Forest Service Pacific Northwest Research Station.
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Actividad 3 - Ecosistemas
¿Que es un ecosistema?
El ecosistema es el conjunto de especies de un área determinada que interactúan entre ellas y con su ambiente abiótico; mediante procesos como la depredación, el parasitismo, la competencia y la simbiosis, y con su ambiente al desintegrarse y volver a ser parte del ciclo de energía y de nutrientes. Las especies del ecosistema, incluyendo bacterias, hongos, plantas y animales dependen unas de otras. Las relaciones entre las especies y su medio, resultan en el flujo de materia y energía del ecosistema.
El significado del concepto de ecosistema ha evolucionado desde su origen. El término acuñado en los años 1930s, se adscribe a los botánicos ingleses Roy Clapham (1904-1990) y Sir Arthur Tansley (1871-1955). En un principio se aplicó a unidades de diversas escalas espaciales, desde un pedazo de tronco degradado, un charco, una región o la biosfera entera del planeta, siempre y cuando en ellas pudieran existir organismos, ambiente físico e interacciones.
Fuente: “¿Que es ecosistema?”.Comisión Nacional para el Conocimiento y Uso de la Biodiversidad. obtenido de https://www.biodiversidad.gob.mx/ecosistemas/quees.html
Mapa_interactivo: https://www.biodiversidad.gob.mx/ecosistemas/mapas/mapa.html
PRINCIPALES TIPOS DE VEGETACIÓN DE LA REPÚBLICA MEXICANA
•BOSQUE TROPICAL PERENNIFOLIO
•BOSQUE TROPICAL SUBCADUCIFOLIO
•BOSQUE TROPICAL CADUCIFOLIO
•BOSQUE ESPINOSO
•BOSQUE DE QUERCUS
•BOSQUE DE PINO
•BOSQUE DE PINO ENCINO
•BOSQUE DE ABIES
•BOSQUE DE PICEA Y PSEUDOTSUGA
•BOSQUE O MATORRAL DE JUNIPERUS
•BOSQUE DE CUPRESSUS
•MANGLAR •BOSQUE DE GALERIA
•BOSQUE MESOFILO DE MONTAÑA
•BOSQUE DE ALNUS
•MANGLAR
•PALMAR
•MATORRAL SUBTROPICAL
BOSQUE TROPICAL PERENNIFOLIO
Tipo de vegetación mas exhuberante de la tierra. La mas rica y compleja de todas las comunidades vegetales. Las especies no tiran sus hojas.
DESCRIPCIÓN: Formada por especies de troncos erectos , copas achatadas mas o menos esféricas. Diámetros de 50 a 80 cm. Hasta 1.5 y 2.0 mts. Tres estratos arbóreos ( 30-45 m, 20m, 6m)
DISTRIBUCIÓN: Este y Sureste del país. Hgo., Pue., Oax., chis., Ver., Tab., Cap., Q.Roo y Yuc.
ALTITUD: de 0 a 1000 m.s.n.m.
PRECIPITACIÓN: 1500 – 3000 y 4000mm. •CLIMA: Am, Af, Cw y Aw
ESPECIES: Swietenia macrophyla (caoba), Cedrela mexicana (cedro rojo)
BOSQUE TROPICAL SUBCADUCIFOLIO
DESCRIPCIÓN: Cuando menos la mitad de las especies tiran sus hojas en la temporada seca, pero por un periodo corto. Altura de 15 a 40 mt, mas frecuente de 20 a 30. diámetros de 30 a 80 cm. Escepto en la parota y Ficus de mas de 3 mt.
DISTRIBUCIÓN: Vertiente del Pacífico y Atlántico, se presenta en manchones discontinuos desde Sin. Hasta Chis. Y de Tam. A Ver.
ALTITUD: de 0 a 1300 m.s.n.m.
PRECIPITACIÓN: 1000 – 1600 mm.
CLIMA: Am, Af, Cw y Aw
ESPECIES: Enterolobium cyclocarpum (parota), Roseodendrum donell-smithii (primavera), Dalbergia granadillo (granadillo), Cordia spp. (cueramo) , Cedrela odorata (cedro rojo), Ficus spp.
BOSQUE TROPICAL CADUCIFOLIO
DESCRIPCIÓN: Las especies tiran sus hojas en la temporada seca, pero por un periodo de cinco o mas meses. Altura de 5 a 15 mt, mas frecuente de 8 a 12. Diámetros menores de 50 cm. Torcidos y ramificados. Troncos de colores llamativos.
DISTRIBUCIÓN: Vertiente del Pacífico y del Golfo en una franja casi continua.se presenta en manchones discontinuos desde Sin. Hasta Chis. Y de Tam. A Ver. ALTITUD: de 0 a 1900 m.s.n.m.
PRECIPITACIÓN: 300 a 1800 mm.
CLIMA: BS, Cw y Aw
ESPECIES: Lisyloma spp, Jatropha sp. , Bursera spp, Leucaena spp., Haematoxylon sp., Prosopis sp., Phitecelobium sp., Ceiba sp. etc.
BOSQUE ESPINOSO
DESCRIPCIÓN: Las especies tiran sus hojas en la temporada seca. Son Comunidades mas o menos caducifolias. Abundan las especies espinosas. Se ramifican muy cerca de la base. Altura de 4 a 15 mt,. Diámetros menores de 50 cm. Torcidos y ramificados. Troncos de colores llamativos.
DISTRIBUCIÓN: Vertiente del Pacífico y del Golfo en franjas discontinuas.
ALTITUD: de 0 a 2200 m.s.n.m.
PRECIPITACIÓN: 350 a 1200 mm.
CLIMA: BS, Bw, Cw y Aw
ESPECIES: Lisyloma spp, Acasia, Prosopis sp., Phitecelobium sp., Bursera etc.
BOSQUE DE QUERCUS
DESCRIPCIÓN: Varían de totalmente perennifolios a totalmente caducufolios,. De cobertura cerrada, pueden formar masa puras o mezclarse con pino y oyamel. Sonde hoja dura y gruesa. Las especies tiran sus hojas en la temporada seca. Mundo 6 géneros 600 especies. México de 150 a 200 especies. Michoacán 30 especies. Altura de 2 A 30 Y HASTA 50 mt,. Diámetros menores de 50 cm.
DISTRIBUCIÓN: En todos los estados de la República, excepto Yuc. Y Q. Roo.
ALTITUD: de 0 a 3,100 m.s.n.m. mas común entre 1200 y 1800.
PRECIPITACIÓN: 600 a 1800 mm.
CLIMA: BS, Cf, Cw , Aw y Am.
ESPECIES: Quercus castanea, Quercus laurina, Q. obtusata, Q. crasipes Es el el segundo tipo de vegetación de mayor importancia forestal en México.
USOS: Madera, carbón, leña, postes para cercas, celulosa y papel, mangos de herramientas, taninos para curtir pieles, etc.
BOSQUE DE PINUS
DESCRIPCIÓN: Comunidades siempre verdes. Recurso de primera importancia por su demanda de madera y por la facilidad de explotación. Por la rapidez de crecimiento y sobre todo por su extensa distribución y buen desarrollo. México 38 sp. 10 var. Y 16 formas. Michoacán 15 especies, 2 var. 3 formas. Altura de 8 a 25 mt, hasta 40 mts. Diámetros 20 a 60 cm. Hasta 1 mtro.
DISTRIBUCIÓN: En todos los estados de la República, excepto Tab., Camp. y Yuc.
ALTITUD: de 300 a 4,000 m.s.n.m.
CLIMA: desde tropical hasta francamente frío.
ESPECIES: Pinus michoacana, P. oocarpa, P. pseudostrpbus, P. patula, P. greguii, P. teocote, P. oaxacana etc. Es el tipo de vegetación de mayor importancia forestal en México.
USOS: Madera, celulosa y papel, leña, construcción, ebanistería, triplay, chapas, cajas, duela, postes, durmientes, muebles etc. Resina.
BOSQUE DE ABIES
DESCRIPCIÓN: Comunidades siempre verdes. Destacan por su majestuosidad y belleza, México 5 sp. 1 var. Altura de 8 a 25 mt, hasta 40 mts. Diámetros 20 a 60 cm. Hasta 1 mtro.
DISTRIBUCIÓN: Dispersa en las principales elevaciones del país. Pico de Orizaba, Popocatétetl, Istacihuatl; Cofre del Perote, Nevado de Toluca, Pico de Tancítaro, Cerro San Andres, Sierra Chincua, Nevado de Colima.En todos los estados de la Republica, escepto Tab., Camp. y Yuc.
ALTITUD: de 2400 A 3600 m.s.n.m.
CLIMA: Templado a francamente frío.
ESPECIES: Abies concolor (B.C.), A. durangensis (Dgo.), A. religiosa (Mich.), A. mexicana (Coah), A. vejarii (N-León y S.L.P). Se asocia con el Bosque de pino y sus usos son similares. Típico árbol de navidad
USOS: Madera, construcción, tejamanil.
BOSQUE DE PSEUDOTSUGA Y PICEA
DESCRIPCIÓN: Comunidades siempre verdes, muy semejante al Bosque de Abies. Habita en sitios sombríos y húmedos, en laderas cañadas y barrancas. Ocupan superficies muy reducidas en medio de los pinares. Cubre superficies muy reducidas Altura de 8 a 25 mt, hasta 40 mts. Diámetros 20 a 60 cm. Hasta 1 mtro.
DISTRIBUCIÓN: Son. Chih., Zac. Dgo y Nuevo León
ALTITUD: de 2000 a 3200 m.s.n.m.
CLIMA: Templado a francamente frío.
ESPECIES: Pseudotsuga menziesii, Picea chihuahuana, P. mexicana.Se asocia con el Bosque de pino y sus usos son similares. Típico árbol de navidad
USOS: Madera
BOSQUE O MATORRAL DE JUNIPERUS
DESCRIPCIÓN:
Enebro, sabino, táscate. Comunidades siempre verdes.Prosperan en condiciones ecológicas diversas. •Altura de 50 cm. Hasta 15 mt, . Diámetros muy reducidos.
DISTRIBUCIÓN: B.C.,Chih, .S,L.P., Jal, Mich, Mex. Mor. Hgo. Pue., Qro- Oax.
ALTITUD: de 1000 a 1500 m.s.n.m.
CLIMA: Cw, Cf, BS.
ESPECIES: Juniperus californica, J. monosperma, J. mexicana, J. flaccida, J. deppeana, J. comitana, J. gamboana., J. monticola.
USOS: fabricación de lápices, bonsai, ornamental.
BOSQUE DE CUPRESSUS
DESCRIPCIÓN: Comunidades siempre verdes. Forman parte del Bosque de escuamifolios, Se asocia con Abies, Pinus y Quercus., Altura de 15 a 35 mt, . Diámetros 20 a 60 cm.
DISTRIBUCIÓN:Dispersa
ALTITUD:de 1800 A 3000 m.s.n.m.
CLIMA: templado subhumedo.
ESPECIES: Cupressus guadalupensis (B.C.), C. lindleyi. Se asocia con el Bosque de pino y sus usos son similares. Típico árbol de navidad.
USOS:Madera, construcción, ornamental. Resiste podas fuertes.
MANGLAR
DESCRIPCIÓN:arboles acuáticos, con raices zancudas que sirven de sostén en el fango lodoso.Altura de 2 a 25 mts. Diámetros 15 a 40 cm.
DISTRIBUCIÓN:Golfo y Pacífico, Lagunas costeras o esteros.
ALTITUD:0 m.s.n.m.
CLIMA:tropical.
ESPECIES:Rhizophora mangle, Avicinia germinans.
USOS:Madera, construccion naval, vigas y durmientes, fabricación de piezas de barcos.
Fuete: https://www.gob.mx/conabio/videos/conabio-ecosistemas-de-mexico
Mapa Interactivo: http://www.paismaravillas.mx/explora.html
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