{"id":136296,"date":"2010-07-03T12:29:03","date_gmt":"2010-07-03T11:29:03","guid":{"rendered":"http:\/\/www.madrimasd.org\/blogs\/universo\/?p=136296"},"modified":"2010-07-05T13:28:53","modified_gmt":"2010-07-05T12:28:53","slug":"las-sabanas-y-su-fertilidad-la-biotecnologia-natural-de-los-ingenieros-del-suelo","status":"publish","type":"post","link":"https:\/\/www.madrimasd.org\/blogs\/universo\/2010\/07\/03\/136296","title":{"rendered":"Las Sabanas y su Fertilidad: La Biotecnolog\u00eda Natural de los Ingenieros del Suelo"},"content":{"rendered":"

\u00bfCu\u00e1les son las causas que determinan la estructura de las sabanas africanas? \u00bfDe donde procede su fertilidad? \u00bfQu\u00e9 factor o factores condicionan su productividad?<\/strong><\/span> Un estudio recientemente publicado en PloS Biology (revista en acceso abierto) muestra unos resultados que os sorprender\u00e1n a la mayor\u00eda de vosotros. El secreto se encuentra en uno de los organismos del suelo a los que los edaf\u00f3logos denominamos ingenieros<\/strong><\/span>. Hablamos de las termitas<\/span><\/strong>. Seg\u00fan los autores, y los resultados son espectaculares, estos organismos y las estructuras que generan dan cuenta de los aspectos fundamentales de la estructura y din\u00e1mica de estos ecosistema<\/span>s<\/span><\/strong>. Su trabajo de biotecnolog\u00eda natural genera una fertilidad estructurada por la cuasi-cristalina configuraci\u00f3n espacial de sus habit\u00e1culos<\/span><\/strong>. Cuanto m\u00e1s entendamos los suelos, mejor comprenderemos los ecosistemas.<\/p>\n

\"la-estructura-de-la-sabana-y-las-termitas-fuente-plos-biology\"\u00a0<\/p>\n

Geometr\u00eda cuasi-cristalina de la disposici\u00f3n de los termiteros en la sabana. Fuente Plos Biology (ver enlace abajo)<\/span><\/p>\n

Personalmente, a mi no me extra\u00f1a. Es una l\u00e1stima que el sesgo agron\u00f3mico de la edafolog\u00eda nos auto-margine de estos estudios. Podemos aportar mucho m\u00e1s a la ecolog\u00eda, cambio clim\u00e1tico y otras ciencias medi\u00e1ticas de lo que lo hacemos hoy en d\u00eda. Y parte del problema se encuentra en nuestra propia inercia.<\/p>\n

<\/p>\n

Las termitas<\/strong><\/span>, a la hora de edificar sus termiteros, remozan los perfiles del suelo<\/span><\/strong> a lo largo de varios metros de profundidad. Se trata de lo que denominamos haploidizaci\u00f3n mediante bioturbaci\u00f3n<\/a>. Ya comentamos en nuestro post \u201cLaterizaci\u00f3n: G\u00e9nesis de Oxisoles, y Termitas<\/a>\u201d, que la posible g\u00e9nesis de suelos muy homog\u00e9neos, como los Oxisoles (Ferralsoles)<\/span><\/strong> pudiera deberse a este tipo de bioturbaci\u00f3n. Hoy albergo aun menos dudas. Del mismo modo, tambi\u00e9n os informamos en nuestra entrega \u201cLa Revoluci\u00f3n Neol\u00edtica de los Organismos del Suelo: Sobre el Ciclo del Nitr\u00f3geno, Monocultivos, Hormigas y Bacterias<\/a>\u201d como, mediante simbiosis con las bacterias<\/span><\/strong>, diversos tipos de insectos sociales enriquecen el medio ed\u00e1fico en uno de sus factores m\u00e1s limitantes para el desarrollo vegetal. Hablamos del nitr\u00f3geno<\/span><\/strong>. Es una l\u00e1stima que entre los autores del art\u00edculo que da pie a este post no hubiera un edaf\u00f3logo, ya que estos investigadores se l\u00edan un poco a la hora de explicar el efecto de la bioturbaci\u00f3n. As\u00ed por ejemplo, comentan que devuelven a la superficie del suelo elementos texturales gruesos que mejoran su estructura y favorecen la infiltraci\u00f3n del agua, que de este modo tiende a impedir su encharcamiento en la estaci\u00f3n de las lluvias. Puede ser. Sin embargo, parte de las fracciones texturales gruesas bien pudieren ser pseudolimos, es decir part\u00edculas del tama\u00f1o del limo que en realidad son agregados de arcillas fuertemente unidas entre si por las abundantes cantidades de sesqui\u00f3xidos de hierro<\/span><\/strong> que caracterizan a los Oxisoles o Ferralsoles. Se trata de suelos pobres en nutrientes, por lo que cualquier \u201cayudita\u201d por parte de los ingenieros del suelo causa un gran efecto en su fertilidad<\/span><\/strong>.<\/p>\n

Pues bien, la productividad primaria y biomasa de la vegetaci\u00f3n aumenta conforme uno se acerca a la boca de los termiteros<\/span><\/strong>. Y as\u00ed, arrastra a todos los restantes elementos de la cadena tr\u00f3fica<\/span><\/strong>. Empero la disposici\u00f3n<\/span><\/strong> de estas megapolis invisibles bajo nuestros pies (bioingenier\u00eda ed\u00e1fica)<\/a> resulta ser extremadamente regular<\/strong><\/span>, es decir no aleatoria. Su disposici\u00f3n espacial emula a una ret\u00edcula cristalina<\/span><\/strong>, cuyos nodos resultan ser los mencionados termiteros. Se trata de una disposici\u00f3n \u00f3ptima con vistas a optimizar los efectos de tales colonias de insectos sociales en ambientes \u00e1ridos y semi\u00e1ridos (ver post: Arquitectura de los Suelos y la Vegetaci\u00f3n en los Ambientes \u00c1ridos y Semi\u00e1ridos<\/a>). Empero si el terreno dista mucho de ser llano, otras configuraciones surgir\u00edan, como ya vimos en aquella ocasi\u00f3n.<\/p>\n

\u00a0\"estrucura-de-las-sabanas-y-termiras-1-fuente-plos-biology-1\"<\/p>\n

Incremento de productividad generada por la geometr\u00eda cuasi-cristalina de la disposici\u00f3n de los termiteros en la sabana. Fuente Plos Biology (ver enlace abajo)<\/span><\/p>\n

\u00a0Resulta incre\u00edble, como se indica en la noticia, que las termitas se hayan tradicionalmente considerado como un serio problema, cuando no una indeseable plaga para la agricultura y la ganader\u00eda de los ambientes sabanoides, cuando en realidad su actividad deviene en una \u201cbendici\u00f3n<\/span><\/strong>\u201d. Tal hecho demuestra la vital importancia de seguir profundizando en la estructura y din\u00e1mica de los sistemas ed\u00e1ficos, as\u00ed como de sus peque\u00f1os biotecn\u00f3logos ecosist\u00e9micos.<\/p>\n

En cualquier caso, no debemos olvidarnos de esos gigantones mam\u00edferos a los que llamamos elefantes<\/span><\/strong>. Ellos son los que permiten la apertura del bosque cerrado para generar pastos arbolados<\/span><\/strong>, cuando estos desaparecen los bosques de acacias vuelven a cerrarse, perdi\u00e9ndose gran parte de la espectacular belleza que les confiere esos magn\u00edficos ensamblajes faun\u00edsticos que atesoran, como ya os explicamos al hablar de las Sabanas Africanas<\/a>.<\/p>\n

\u00a0Juan Jos\u00e9 Ib\u00e1\u00f1ez<\/span><\/strong><\/p>\n

\u00a0 El Trabajo Original puede bajarse pinchando en t\u00edtulo del trabajo<\/strong><\/span>, es decir, a rengl\u00f3n seguido.<\/p>\n

\u00a0<\/p>\n

\u00a0<\/p>\n

Spatial Pattern Enhances Ecosystem Functioning in an African Savanna<\/a><\/h3>\n

Otros post previos relacionados con el tema<\/span><\/strong><\/p>\n

Arquitectura de los Suelos y la Vegetaci\u00f3n en los Ambientes \u00c1ridos y Semi\u00e1ridos<\/a><\/p>\n

Sabanas Africanas: Estructura de la Vegetaci\u00f3n, Grandes Mam\u00edferos y Diversidad de Suelos (Edafodiversidad)<\/a><\/p>\n

Sabanas Mediterr\u00e1neas<\/a><\/p>\n

Laterizaci\u00f3n: G\u00e9nesis de Oxisoles, Ultisoles y las Termitas<\/a><\/p>\n

La Evoluci\u00f3n Simbi\u00f3tica: Innovaci\u00f3n a trav\u00e9s de Simbiosis (Sobre bacterias, Insectos Sociales y Ciclos Biogeoqu\u00edmicos)<\/a><\/p>\n

Hormigas y Hormigueros: Civilizaciones y Megapolis Invisibles Bajo Nuestros Pies (Bioingenier\u00eda Ed\u00e1fica)<\/a><\/p>\n

La Revoluci\u00f3n Neol\u00edtica de los Organismos del Suelo: Sobre el Ciclo del Nitr\u00f3geno, Monocultivos, Hormigas y Bacterias<\/a><\/p>\n

Horizonaci\u00f3n versus Haploidizaci\u00f3n: Mecanismos Naturales de Destrucci\u00f3n de los Horizontes del Suelo<\/a><\/p>\n

Nota de Prensa<\/span><\/strong><\/p>\n

\u00a0The Star Of Africa’s Savanna Ecosystems May Be The Lowly Termite<\/a><\/h3>\n

\u00a0Terradaily<\/strong><\/span>: by Staff Writers; Cambridge, MA (SPX) Jun 01, 2010<\/p>\n

The majestic animals most closely associated with the African savanna, fierce lions, massive elephants, towering giraffes may be relatively minor players when it comes to shaping the ecosystem.<\/p>\n

Termite mounds, seen here in Kenya’s Masai Mara as an oasis of green in a sea of brown, help support savanna biodiversity at all levels, from tiny insects to this family of cheetahs. <\/em><\/p>\n

The real king of the savanna appears to be the termite<\/strong>, say ecologists who’ve found that these humble creatures contribute mightily to grassland productivity in central <\/strong>Kenya<\/strong> via a network of uniformly distributed colonies.<\/p>\n

Termite mounds greatly enhance plant and animal activity at the local level, while their even distribution over a larger area maximizes ecosystem-wide productivity<\/strong>. The finding, published this week in the journal PLoS Biology<\/strong>, affirms a counterintuitive approach to population ecology: Often it’s the small things that matter most<\/strong>.<\/p>\n

\u00abIt’s not always the charismatic predators – animals like lions and leopards – that exert the greatest control on populations,\u00bb says Robert M. Pringle, a research fellow at Harvard University. \u00abAs E.O. Wilson<\/strong> likes to point out, in many respects it’s the little things that run the world. In the case of the savanna<\/strong>, it appears these termites have tremendous influence and are central to the functioning of this ecosystem<\/strong>.\u00bb<\/p>\n

Prior research on the Kenya dwarf gecko initially drew Pringle’s attention to the peculiar role of grassy termite mounds, which in this part of <\/strong>Kenya<\/strong> are some 10 meters in diameter and spaced some 60 to 100 meters apart<\/strong>. Each mound teems with millions of termites<\/strong>, who build the mounds over the course of centuries.<\/p>\n

After observing unexpectedly high numbers of lizards in the vicinity of mounds<\/strong>, Pringle and his colleagues began to quantify ecological productivity relative to mound density. <\/strong>They found that each mound supported dense aggregations of flora and fauna: Plants grew more rapidly the closer they were to mounds, and animal populations and reproductive rates fell off appreciably with greater distance<\/strong>. What was observed on the ground was even clearer in satellite imagery<\/strong>. Each mound <\/strong>– relatively inconspicuous on the Kenyan grassland – stood at the center of a burst of floral productivity<\/strong>.<\/p>\n

More importantly, these bursts were highly organized in relation to one another, evenly dispersed as if squares on a checkerboard<\/strong>. The result, says Pringle, is an optimized network of plant and animal output closely tied to the ordered distribution of termite mounds<\/strong>.<\/p>\n

\u00abIn essence, the highly regular spatial pattern of fertile mounds generated by termites actually increases overall levels of ecosystem production<\/strong>. And it does so in such a profound way,\u00bb says Todd M. Palmer, assistant professor of biology at the University of Florida and an affiliate of the Mpala Research Centre in Nanyuki, Kenya. \u00abSeen from above, the grid-work of termite mounds<\/strong> in the savanna is not just a pretty picture. The over-dispersion, or regular distribution of these termite mounds, plays<\/strong> an important role in elevating the services this ecosystem provides.\u00bb<\/p>\n

The mechanism through which termite activity is transformed into far-reaching effects on the ecosystem is a complex one<\/strong>. Pringle and Palmer suspect termites import coarse particles into the otherwise fine soil in the vicinity of their mounds<\/strong>. These coarser particles promote water infiltration of the soil, even as they discourage disruptive shrinking and swelling of topsoil in response to precipitation or drought<\/strong>. The mounds also show elevated levels of nutrients such as phosphorus and nitrogen<\/strong>. All this beneficial soil alteration appears to directly and indirectly mold ecosystem services far beyond the immediate vicinity of the mound.<\/p>\n

While further studies will explore the mechanism through which these spatial patterns of termite mounds emerge, Pringle and Palmer suggest that the present work has implications beyond the basic questions of ecology<\/strong>. \u00abTermites are typically viewed as pests, and as threats to agricultural and livestock production<\/strong>,\u00bb Pringle says. \u00abBut productivity – of both wild and human-dominated landscapes – may be more intricately tied to the pattern-generating organisms of the larger natural landscape<\/strong> than is commonly understood.\u00bb<\/p>\n

The findings also have important implications for conservation<\/strong>, Palmer says. \u00abAs we think restoring degraded ecosystems, as we think about restoring coral reefs, or restoring plant communities, this over-dispersed pattern is teaching us something<\/strong>,\u00bb he says. \u00abIt’s saying we might want to think about doing our coral restoration or plant restoration in a way that takes advantage of this ecosystem productivity enhancing phenomenon.\u00bb<\/p>\n

Pringle and Palmer’s co-authors on the PLoS Biology paper are Daniel F. Doak of the Mpala Research Centre and the University of Wyoming; Alison K. Brody of the Mpala Research Centre and the University of Vermont; and Rudy Jocque of the Royal Museum for Central Africa in Tervuren, Belgium. Their work was supported by the Sherwood Family Foundation and the National Science Foundation.<\/p>\n

Resumen del Trabajo Original<\/span><\/strong><\/p>\n

Abstract<\/span><\/strong><\/p>\n

The finding that regular spatial patterns can emerge in nature from local interactions between organisms has prompted a search for the ecological importance of these patterns<\/strong>. Theoretical models have predicted that patterning may have positive emergent effects on fundamental ecosystem functions, such as productivity<\/strong>. We provide empirical support for this prediction. In dryland ecosystems, termite mounds are often hotspots of plant growth (primary productivity)<\/strong>. Using detailed observations and manipulative experiments in an African savanna, we show that these mounds are also local hotspots of animal abundance (secondary and tertiary productivity)<\/strong>: insect abundance and biomass decreased with distance from the nearest termite mound<\/strong>, as did the abundance, biomass, and reproductive output of insect-eating predators. Null-model analyses indicated that at the landscape scale, the evenly spaced distribution of termite mounds produced dramatically greater abundance, biomass, and reproductive output of consumers across trophic levels than would be obtained inlandscapes with randomly distributed mounds<\/strong>. These emergent properties of spatial pattern arose because the average distance from an arbitrarily chosen point to the nearest feature in a landscape is minimized in landscape<\/strong>s where the features are hyper-dispersed (i.e., uniformly spaced)<\/strong>. This suggests that the linkage between patterning and ecosystem functioning<\/strong> will be common to systems spanning the range of human management intensities. The centrality of spatial pattern to system-wide biomass accumulation underscores the need to conserve pattern-generating organisms and mechanisms<\/strong>, and to incorporate landscape patterning in efforts to restore degraded habitats and maximize the delivery of ecosystem services.<\/p>\n

(\u2026) with the result that ecosystem-wide productivity is greater under the actual distribution of mounds than it would be if the same number of mounds were randomly situated.<\/p>\n","protected":false},"excerpt":{"rendered":"

\u00bfCu\u00e1les son las causas que determinan la estructura de las sabanas africanas? \u00bfDe donde procede su fertilidad? \u00bfQu\u00e9 factor o factores condicionan su productividad? Un estudio recientemente publicado en PloS Biology (revista en acceso abierto) muestra unos resultados que os sorprender\u00e1n a la mayor\u00eda de vosotros. El secreto se encuentra en uno de los organismos del suelo a los que los edaf\u00f3logos denominamos ingenieros. Hablamos de las termitas. Seg\u00fan los autores, y los resultados son espectaculares, estos organismos y las estructuras que generan dan cuenta de los aspectos fundamentales de la estructura y din\u00e1mica de estos ecosistemas. Su trabajo de\u2026<\/p>\n","protected":false},"author":26,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0},"categories":[596,603,590,613,600,598],"tags":[46810,46807,46711,1843,46809,1845],"blocksy_meta":{"styles_descriptor":{"styles":{"desktop":"","tablet":"","mobile":""},"google_fonts":[],"version":4}},"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/posts\/136296"}],"collection":[{"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/users\/26"}],"replies":[{"embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/comments?post=136296"}],"version-history":[{"count":8,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/posts\/136296\/revisions"}],"predecessor-version":[{"id":136605,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/posts\/136296\/revisions\/136605"}],"wp:attachment":[{"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/media?parent=136296"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/categories?post=136296"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/tags?post=136296"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}