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Advisor(s)
Abstract(s)
The European river lamprey, Lampetra fluviatilis (L.), and the European brook lamprey, Lampetra planeri
(Bloch, 1784), are considered highly threatened in Portugal. However, the lack of information about
the ecology and distribution of these species poses difficulties to the identification of concrete actions
directed to their conservation. A total of 401 sampling sites, randomly distributed throughout the entire
Portuguese mainland territory were selected, and Lampetra sp. ammocoetes presence or absence checked
with electrofishing. These data, together with 11 macrohabitat predictors, were analyzed using Boosted
Regression Trees (BRTs). The BRT models consistently identified five environmental variables as the most
important for predicting the distribution of European brook and river lamprey ammocoetes: altitude, distance
to coast, sand, maximum temperature of the warmest month and precipitation of the driest month.
The relationships of these variables with the species probability of occurrence suggest that lampreys
occur in low altitude river stretches (<170 m), relatively close to the coast (<150 km) and with a sandy
substrate (>70% sand). In addition, intermediate values of temperature and precipitation were also found
to have a positive correlation with the species occurrence. A map with the probability of occurrence of
Lampetra sp. in Portugal was generated and stretches of rivers were delimited with different conservation
priorities. Rivers classified with the highest level of conservation priority were considered to be proposed
as Special Areas of Conservation, under the Natura 2000 Networking Programme.
Description
Keywords
L. fluviatilis Lampetra planeri Predictive model Boosted regression trees Threatened species Portugal
Citation
Biological Conservation, 159, 175-186