The Kaļķupe River valley was established as the Pilsupe River (formed by Kaļķupe River and Mazupe River) crossed the Blue hills of Šlītere to the South of Vīdale and Kaļķi. The distinct river valley has a branched network of gullies in which Devonian sandstone has been uncovered and can be seen in some locations. Puiškalns Hill (located at confluence of Kaļķupe River and Mazupe River), which was used as a castle hill and as a sacred location long in the past, is one of the most distinctive parts of the area. It is a popular tourist destination in the Talsi District. Hillside forests, various kinds of meadows and a wide range of plants are also of value in the local environment.

This territory was established to protect the rare tree specie in Latvia - common hornbeam, which covers approximately 4% of the territory, but the most visually interesting part of the area is the Tīrspurvs swamp, also known as the Dunika heath. This is where the visitor will find Latvia’s longest and most impressive swamp footpaths, which crosses the area from the North to the South. Visitors will be fascinated by the unique landscape of the central part of the swamp, where in some places there are not even small swamp pine trees. Various habitats will be found – small swamp lakes, mineral islands, marsh pools, etc., and that is to say nothing of all the birds in the area.

The Grey Dune of Pāvilosta nature reserve covers 42 hectares of land and has been designated to protect Latvia’s widest dune (1.5 km parallel the seacoast, and 812m in the direction from the sea to inland) and the biotopes and species found there. A two-storied watching platform is built to savour the scenery.

 In Soviet time, local fishermen used to dry seaweed in dunes for production of agar, and thus rich vegetation developed in the dune. The Gray Dune is part of a unique landscape with the sea view, the traditional architecture of Pāvilosta fishing town, and biotopes, including protected, which border the nature reserve: pine forest, embryonic dunes, white dunes, and wet beech where once can find springs. Biotope 2130, “Fixed dunes with herbaceous vegetation (grey dunes)” is found here. At present, pines are taking over the biotope, therefore some maintenance activities are required. The Grey Dune is most beautiful in the second half of July and in August when the blossoming Breckland Thyme (Thymus serpyllum) and Narrowleaf Hawkweed (Hieracium umbellatum) colour the dune in shades of yellow and violet. The most typical species here are Pasqueflower (Pulsatilla pretense), Grey Hair-grass(Corynephorus canescens), Blue Hair Grass (Koeleria glauca), Sand Pink (Dianthus arenarius).

The Gray Dune earned wide recognition when a group of enthusiasts actively campaigned for six years to achieve the status of the nature reserve. Guna Grimsta, a group representative remembers that they organised events and activities throughout Latvia involving large part of the society, prominent personalities, church parishes, NGOs, school youth and university students. The activists were writing letters, making videos, doing research articles, composing music, collecting signatures and submitting proposals to achieve official status of the Grey Dune as an especially protected nature site. They organised seminars, concerts, art plenaires and exhibitions, educational excursions, joint-work, musical church services, meetings with high officials and their on-site visits to the Gray Dune.

In 2006 the group received the title „Proudness of Latvia” awarded by the national TV3 broadcasting company and daily paper „Diena”.
The nature reserve „Gray Dune of Pāvilosta” was established in October 30, 2007. It is the most recent Natura2000 site in Latvia.

This lime swamp of grasses is in an area among dunes which floods from time to time, and it is an important location for many protected plants. The swamp is easily surveyed from the forested dunes which are on the south-eastern side of the swamp.