Nature values

SEAmBOTH project is nearing its end, and with it comes also final results. One of the main tasks of SEAmBOTH has been the identification of most valuable areas. In order to protect nature, we first need to know where valuable features are.

The analysis flow how nature values can be defined, can look something like this: 1) Define what nature values are, i.e. what do we want to conserve, 2) collect relevant data for the estimation, such as species distribution and corresponding environmental data where species is dwelling, 3) approximate the distribution of species (or habitat) in your analysis area with ways of, for instance, statistical modelling, 4) estimate potential threats facing nature, such as human activities leading to habitat destruction 5) integrate all developed data into a map representing nature values, with suitable methods, such as spatial conservation prioritization.

In SEAmBOTH we have followed this path, and now the results are ready.

1.    Define “nature values”

First, marine biologists defined what valuable nature is with the MOSAIC tool (see details in here and here). Habitats, nature types and species were given scores from an ecological point of view. Higher the score, more relevant it was considered for the whole marine ecosystem. Elevated scores were given for instance to species or habitats known to contribute to overall biodiversity or functioning of the whole marine ecosystem. Such were for instance, fish reproduction areas, and fourleaf mare´s tail (Hippuris tetraphylla) meadows.

2.    Collect data on species and environments

SEAmBOTH has collected data for the past years using various methods, such as diving, wading and dropvideo, and results from the biological inventories are presented here. If combining all the data we have from the whole SEAmBOTH area, around 23,000 sites have been visited (Fig. 1). That has been a huge effort!

Figure 1. Map of sites where biological inventories have taken place (Map by Elina Virtanen, SYKE)

Moreover, environmental data has been developed, which describe the environment where species is living, and covers factors such as salinity, seafloor substrate, depth and turbidity. Data for this has been gathered through remote sensing (Fig. 2) and by the means of geological surveys.

Figure 2. Turbidity during growing season 2015–2018 estimated from Sentinel-2 instrument (before the removal of shallow areas with uncertain turbidity values). (Map by Elina Virtanen, SYKE)

3.    Ecological modelling

Combining the information from the field (species data) and developed environmental data, statistical modelling can be used to draw correlative conclusions about species and its habitat and use that information to predict species distribution patterns across the seascape. All in all, ecological models were built for 112 species (Fig. 3), including for instance water mosses, charales, macrophytes, and threatened species, such as Baltic water-plantain (Alisma wahlenbergii) (Fig. 4).

Figure 3. Share (%) of developed models.

Figure 4. Probability (%) of finding Alisma wahlenbergii in SEAmBOTH study area with zoomed-in examples. (Map by Elina Virtanen, SYKE)

4.    Threats facing nature values

Human activities can have a profound effect on the marine environment. Habitats can be degraded due to resuspension of sediments from marine traffic, or totally lost due to dredging activities (Fig. 5). Estimation of human activities causing pressures to nature values were based on expert judgement of the severity and intensity of the effect each activity is causing, in a MOSAIC-like fashion. Moreover, extents of activities were estimated. 

Figure 5. Small-scale dredging interpreted from aerial images and zoomed-in examples. Black color marks dredged areas and red-orange-yellow color the gradient and extent of dredging. (Map by Elina Virtanen, SYKE)

5.    Spatial conservation prioritization

Finally, all the developed ecological and marine threat models were integrated with a spatial prioritization tool Zonation, developed for ecologically-informed land use planning. As an output, user gets a balanced ranking across the seascape, by iteratively removing cells that can be lost with smallest aggregate loss for biodiversity. Areas receiving high rank values are key areas from conservation point of view – species-rich areas, hosting various highly weighted species and habitats – and lowest degraded, pressurized areas, holding less ecological value. In SEAmBOTH area, high nature values are located for instance in shallow bays and river estuaries, which are home to juvenile fish and various threatened and rarely occurring species. In addition, valuable areas are also located in the outer archipelago, in exposed islands with less human disturbance (Fig. 6). Let´s keep it that way also in the future.

Figure 6. Nature values in the SEAmBOTH area, as defined by MOSAIC and Zonation. (Map by Elina Virtanen, SYKE)

Written by Elina Virtanen, Finnish Environment Institute

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