Working on high elevation

As part of the  LIFE Pterodromas4Future project  and the  LIFE Natura@Night campaign , SPEA is doing measurements of artificial light at night (ALAN) on different sites on Madeira. One of the sites we performed measurements was located at Pico Ruivo (1861 m), the highest point of Madeira Island.

Pico Ruivo is located in the Santana municipality, near the center of Madeira. The peak is only reachable by foot and it is a popular tourism activity to do a hike to the top, either via PR 1.2 or via PR 1.1. The latter connects Pico Ruivo to the second highest point of Madeira, Pico Areeiro. PR 1.1 is the most popular hike of Madeira and also the most strenuous because of all the stairs that have to be climbed. At the time of this publication (November 2024), the trail is closed because of the fires of August 2024 that destructed part of the trail. But Pico Ruivo remains reachable via PR 1.2.

Standing on the Pico Ruivo, it is possible to view Faial (east), Curral das Freiras (south-west), the valleys of Ribeira Grande and São Jorge (north) and on a clear day, the Desertas Islands (south-east) and Porto Santo Island (north-east). Because it's high elevation, the flora on the peak mainly consists of heaths, very strong plants that are able to live in this rough environment. At the time of measurement, the iconic and endemic flower of Madeira, the Echium candicans (Massaroco/ Pride of Madeira), was in full bloom which made the site even more beautiful.

Different bird species inhabit the area, including the Regulus ignicapilla madeirensis (Bis-bis/Madeira firecrest) and the Fringilla maderensis (Tentilhão/Madeiran chaffinch). The Tentilhão are easier to spot as the regularly approach visitors trying to get some food.

The inland mountainous of Madeira is an important habitat for the emblematic seabird species, the Pterodroma Madeira (Freira da madeira/ Zino's petrel). The Freira da Madeira, and also the other seabird species of Madeira, are greatly impacted by ALAN. They can get disoriented by artificial light sources in their travels to the sea and consequently collide with building or get 'grounded' on streets, making them vulnerable to predators and traffic. As the Freira da Madeira is already classified as Threatened ( IUCN Red List) , limiting ALAN is very important and measuring the extent and intensity of artificial light is a first step towards better policies and awareness.

During the years 2023 and 2024, SPEA Madeira conducted measurements at Pico Ruivo using a camera with a fisheye lens and as special gadget called a TAS to capture the artificial light. Because we wanted to both capture the Northern and the Southern side of the island, we set up the camera on two points.

After arriving to the measurement point, we set up the camera and made sure that it was well secured, we didn't want it to fly away. We then started the process of taking pictures before sunset and repeated this at around 23:00 and 01:00. For this, we always point the lens towards the North, East, South and West.

To be able to represent the light pollution most accurately, it is ideal to have a clear sky. This is hard to get on Madeira but for this day and site, the conditions were ideal, apart from the cold after sunset.

Alongside taking pictures of the sky, we also performed TAS measurements. This helps us to get a better understanding of the intensity and distribution of artificial light around the site. After the TAS measurement, we get a visual representation as can be seen in the figures below. Together with the pictures we take, we can interpret the light pollution in the surrounding area and compare it across time and location. Changes across time can occur due to environmental conditions that may vary (like moon phase, cloud coverage) but also due to changes in light infrastructure in the area. Preferably the intensity of artificial light will decrease over time as awareness and efforts from municipalities and residents to mitigate the effects of artificial light will increase.