El desmán ibérico
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Malas noticias desde Portugal

In 1993-96, desmans were recorded at 85.1% of sites, and their presence was positively related to stream order and slope. In 2014-15, desmans were only found at 31.1% of sites, and their presence was positively related to slope steepness and negatively to stream order and maximum temperature of the warmest month. The extinction rate across periods was 63.5%, and the probability of extinction increased with stream order and declined with slope steepness. Maps of predicted distribution and extinction indicated that while the species was widely distributed in the first period, it largely disappeared thereafter from the main rivers and the largest tributaries, persisting mostly in stream headwaters in more mountainous areas. The severe decline found in ours and other studies suggest that the conservation status of the Pyrenean desman may need to be upgraded, and highlights the importance of headwater streams for its conservation. Furthermore, this study supports the view that headwater streams may be increasingly important for biodiversity conservation in modified river systems, favouring the permanence of remnant, albeit fragmented populations.

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Need for speed. Cuanto más rápido, mejor.

Need for speed

The results highlight the ecological relevance of riffles as foraging habitats of desmans, and therefore as key features for their conservation. It suggests that channel modifications that reduce the areal cover of riffles impair habitat quality for this species. In addition, water diversion for hydropower is likely to be detrimental for desmans, as it reduces discharge and flow velocity in the bypassed river sections.

Need for speed. Preference for fast-flowing water by Pyrenean desman Esnaola et al 2018

Malas noticias para el desmán ruso

DESMAN RUSO

The population of the Russian desman in all historical areas is currently no more than 8000–10,000 individuals. The estimated population size of the Russian desman is based on direct surveys during 2010–2016. We observed over 266 km of the coastline in eight regions where the desman lives. Since the early 20th century the number of specimens has been steadily declining. In addition to the previously described factors that determine the reduction of the population size, such as land reclamation, the construction of hydroelectric stations and the flourishing of poaching at the end of
the last century, the status of the Russian desman population is adversely affected by periodic droughts and the absence of floods. Currently Protected Areas remain as the only passive measure to protect the Russian desman in the absence of a programme to species protection nor state support.

Russian Desman at the edge of disappearance_Rutovskaya et al 2017

Desmaneando. LIFE Irekibai

Irekibai, ríos abiertos. De momento un deseo, la realidad es bien diferente. El agua de nuestros ríos encuentra muchos obstáculos y en ocasiones discurre por donde no debe. El proyecto IREKIBAI pretende corregir esta situación, al menos en parte. Varias especies de vertebrados actuarán como indicadores de la eficacia de las acciones de restauración que se van a desarrollar en los próximos años. Entre ellas el desmán.

Durante los próximos meses volveremos a hacernos la eterna pregunta ¿Qué hace que un río deje de ser apto para el desmán? ¿Cuáles son los factores clave? Hace unos días salimos en la tele. Nada nuevo bajo el sol (o sí, según se mire). Unas imágenes de unos cuantos desmanes vivos y coleando siempre merecen la pena.

Una taxidermia “original”

desman-n_7desman-235n_7

MUSEUM D’HISTOIRE NATURELLE. Perpignan.

El desmán abulense

Abulenses y cacereños, los desmanes del Sistema Central. De momento. Ojalá aparezca algún segoviano (o algún salmantino), que haya pasado desapercibido.

Ahora hace falta que la Confederación Hidrográfica del Duero y la Junta de Castilla y León cumplan y den al hábitat del desmán la protección necesaria. No olvidemos que únicamente se ha redescubierto una población olvidada. No es poca cosa, pero el trabajo por el que enorgullecerse está aún por hacer.  

Tan pancho

bolitabolita_2Fotografías: cortesía de Iñaki Irizar