Environmental factors affect the distribution of Iberian spiders


Newswise – Southern smallleaf oak forests are the habitats with a higher level of spider endemism in the Iberian Peninsula, according to an article in the newspaper Biodiversity and conservation. The study analyzes the factors that affect the biodiversity patterns of spider communities in the network of national parks of Spain and explains the role of environmental factors in the distribution of the biodiversity of this faunistic group in the peninsular territory.

The study is led by Professor Miquel Arnedo, from the Faculty of Biology and the Biodiversity Research Institute (IRBio) of the University of Barcelona, ​​and counts on the participation of experts Luis Carlos Crespo, Marc Domènec and Carles Ribera (UB-IRBio), Jagoba Malumbres-Olarte and Pedro Cardoso, from the University of the Azores (Portugal), and Jordi Moya-Laraño, from the Arid Zones Experimental Station of Almeria (EEZA-CSIC).

Iberian spiders: how are they distributed throughout the peninsular territory?

There are many doubts about the biology and ecology of the Iberian spider communities, a group with a fundamental role in natural ecosystems. There could be more than 1,400 species in the peninsular territory, which has great climatic diversity and natural habitat. In some cases, there are species with limited distribution – regional or local endemism – and this would explain the changes observed between communities in different areas.

The new study focuses on the study of spider communities in the national parks of Aigüestortes i Estany de Sant Maurici, Ordesa y Monte Perdido, Picos de Europa, Monfragüe, Cabañeros and Sierra Nevada. In particular, they studied spider communities – a total of 20,552 specimens from 375 species – in different types of oaks (Quercus spp), widely distributed around the peninsula, such as those which include the sessile oak (Quercus petraea), Valencia oak (Quercus faginea) and the Pyrenean oak (Quercus pyrenaica).

“The results show that the oak forests of Valencia (Q. faginea) are those that have a greater number of spider species, probably due to the combined effects of the physical structure of the habitat and climatic conditions “, notes Professor Miquel Arnedo, of the Department of Evolutionary Biology, of ecology and environmental science.

The study also confirms previous studies which indicate a decrease in species in southern forest ecosystems, which is caused by the reduced connectivity of ecosystems with the rest of the continent.

“However, we suggest that these changes in the number of species could be the result of complex interactions between geographic position, habitat and local climate. This would allow us, for example, to find communities of spiders in the Cabañeros National Park (Castilla – La Mancha) with a greater number of species than in Picos de Europa (Asturias) “, notes Arnedo.

Climate, geography and endemism of Iberian spiders

Another relevant contribution of the study is the identification of a model that relates the increase in the level of endemism in spider communities with the increase in temperatures and decrease in annual precipitation, which are typical of the climate. Mediterranean.

“Spider communities in Mediterranean areas seem to be more endemic – when we consider the distributions of all species in each community – and have a higher number of exclusively Iberian species”, notes expert Jagoba Malumbres-Olarte, first signatory of the article. Other groups of spiders exhibit a higher level of endemism based on certain ecological characteristics, according to the authors.

“In this case, we have seen that the spiders that spread more frequently through the air using silk, called hot air balloons, have a wider geographic distribution and are therefore less endemic. For example, this would be the case with some. species of the family Lindyphiidae “.

Spiders, indicators of environmental quality

Despite the ecological value of spiders, these arthropods have rarely been used as bioindicators. This study sheds light on this area of ​​ecological study, and suggests that the presence and abundance of spider families with high levels of endemism – for example, the families Oonopidae, Dysderidae, Zodariidae and Sparassidae – could be utilized by spiders. researchers as indicators of the singularities and ecological qualities of certain natural spaces.

“In the communities studied, these families are those with a higher level of endemism. If we consider the difficulty of identifying certain Iberian species and the probability of finding undescribed species, the option of using families of spiders – instead of species – could facilitate the use of spiders as ecological and conservation indicators, ”say the authors.

Improve biodiversity conservation strategies

The lack of many experts able to identify and describe spider species and the great diversity of this group are factors that make it difficult for researchers to study the ecology of Iberian spider communities, and by extension, many more. The expansion of knowledge on the biodiversity of the peninsular spider fauna requires the promotion of monitoring programs and regular monitoring of temporary changes in communities.

In this context, the article published in the journal Biodiversity and conservation provides new information to improve the conservation and management of national parks and protected areas in general. It reveals new data on the number and composition of species in national park communities, information that provides a baseline for future monitoring plans. In addition, it identifies the most relevant groups based on their endemic levels (i.e. those with potentially high values ​​for conservation).

“Our study also indicates that different habitats within a single area or park may have differential value in terms of conservation and scientific interest, and therefore, may be subject to multiple levels of prioritization in conservation actions, ”the researchers conclude.



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