Biodiversity is the variety of life on earth and is important to most aspects of our lives. We value biodiversity both for what it provides to humans, such as food, fuel, shelter, medicine, pollination, seed dispersal, climate regulation, water purification, nutrient cycling, and control of agricultural pests, and for the value it has in its own right. Biodiversity also holds value for potential benefits not yet recognized, such as new medicines and other possible unknown services.
Protected areas are sites which receive protection because of the biodiversity they contain. One would expect declines in biodiversity to be less inside protected areas than outside them, as they often have management agreements aimed to protect biodiversity. We used long-term datasets describing change in plant communities across Scotland between the 1940s and 2000’s to assess if vegetation change differed between plots located inside and outside protected areas. We found that whether a plot was located in a protected area or not, had no influence on the change in abundance of plant species groups or change in species number. It seems likely factors operating at scales larger than the protected areas, such as pollution or climate change, were likely to have been the main causes of vegetation change. However, protected area status may have stopped plots from being destroyed.
Stage
Work in ProgressDirectory of Expertise
Purpose
Protected areas are locations which receive protection because of their recognized natural and ecological value. International directives and treaties, domestic legislation and policy, or local needs and interests may legislate for the designation of sites. Protected areas, also known as designated sites, aim to protect biodiversity and geodiversity, both now and for the future.
One might expect that changes in biodiversity would be less within protected areas than outside as protected areas often have management agreements aimed to protect the biodiversity. Protected areas are one method to reduce the Biodiversity Crisis (the current decline in biodiversity). It is therefore important to understand if biodiversity within protected areas is protected, ie if the change in biodiversity in protected areas is less than outside them. Are protected areas effective?
Therefore, we tested this using two long term vegetation datasets the Birse and Robertson (B&R) data set and the McVean and Ratcliffe (McV&R) data set. These data sets describe vegetation composition in 1772 plots distributed across Scotland which were first surveyed between 1945-1985 and then revisited and resurveyed between 2004-2014. We used these data to assess if vegetation change in plots located inside protected areas was different from that in plots located outside protected areas. In this study protected areas included Ramsar sites, Special Area of Conservation (SAC), Special Protected Areas (SPA), National Nature reserves (NNR), Sites of Special Scientific Interest (SSSI) and Local Nature Reserves (LNRs). The vegetation plots included in the study covered a wide range of habitats across Scotland: alpine, grassland, moorland, wetland, woodlands (Table 1) and types of protected areas (Table 2). We grouped the plant species found in the plots into mosses and liverworts, dwarf shrubs, forbs, grasses, lichens, ferns, sedges and rushes and calculated the overall change in cover and species richness of each of these groups.
|
|
Protected area |
|
|
|
NO |
YES |
Total |
|
|
B&R |
|
|
|
|
Alpine |
29 |
176 |
205 |
|
Grassland |
458 |
101 |
559 |
|
Moorland |
242 |
143 |
385 |
|
Wetland |
52 |
55 |
107 |
|
Woodland |
133 |
130 |
263 |
|
McV&R |
|
|
|
|
Alpine |
13 |
78 |
91 |
|
Grassland |
14 |
42 |
56 |
|
Moorland |
27 |
51 |
78 |
|
Wetland |
2 |
26 |
28 |
|
Total |
970 |
802 |
1772 |
Table 1: Number of plots surveyed in the two datasets, Birse and Robertson (B&R) and McVean and Ratcliffe (McV&R) by habitat and protected area status.
|
Type of protected area |
Habitat |
||||
|
Alpine |
Grassland |
Moorland |
Wetland |
Woodland |
|
|
Ramsar |
|
3 |
|
5 |
4 |
|
SAC |
173 |
79 |
110 |
37 |
102 |
|
SPA |
132 |
32 |
72 |
12 |
35 |
|
NNR |
77 |
43 |
54 |
29 |
46 |
|
SSSI |
236 |
133 |
184 |
77 |
121 |
|
LNR |
|
|
|
1 |
|
Table 2: Number of plots located in each type of protected area. Protected areas designations often overlap, thus it was not possible to separate out the impact of different types of protected areas.
The analysis took account of the fact that some plots were geographically closer to each other than others and therefore might have been expected to show more similar patterns of change (called spatial correlation).
Results
We found that plot location inside or outside a protected area had no influence on the change in cover or number of species in any of the species’ groups. In both the initial survey and the resurvey there were differences between the vegetation inside and outside protected areas. For example, with the mosses and liverworts (Figure 1) there were more species per plot inside the protected areas than outside on both visits. However, the number of species per plot declined between the first and second surveys in both protected and unprotected areas and there was no evidence for a significant difference in the rate of change between protected and unprotected areas.
Figure 1: The number of mosses and liverworts recorded in the first and second visits (Visit 1, Visit 2) in plots inside protected areas (PA) and outside protected areas (Not PA). The data shows that there are more species in the protected areas than not, but there was a decline in the number of species between visits for both protected and unprotected areas so no significant difference in the change. The boxplot shows the median and spread of values. The box (shown in blue) shows the range between the 25th and 75th percentiles (the interquartile range) and whiskers (defined as the largest or smallest value no further than 1.5 x the interquartile range). Data beyond the end of the whiskers are plotted individually.
Previous SEFARI work (see research papers below) which have analyzed these datasets as separate habitats have shown that global drivers such as pollution or climate change are key drivers of vegetation change. Such drivers are beyond the control of the individual land managers and operate at a scale beyond that of a protected site. Thus, while protected area status may have contributed to maintaining the vegetation as ‘better’ than vegetation in unprotected areas, there was no difference between plots in protected areas and those outside in the scale of change over time. It should also be noted that protected area status may have stopped plots from being destroyed or changed from semi-natural habitats into arable or urban habitats, such plots were not resurveyed in this project.
Benefits
This work provides evidence that although protected area status may maintain a difference in vegetation quality, as measured by the number of species and composition, between protected and unprotected areas, the rate of change in the number of species and abundance of species does not differ. It is therefore important not only to maintain protected areas but also to address the drivers of change that are operating at a larger scale such as pollution and climate change.
Just because a plot is within a protected area does not necessarily mean that the protected area has received the optimum management to maintain the vegetation. Many protected areas are in unfavorable condition. In March 2023 NatureScot reported that only 76.4% of protected areas were in favourable condition. In addition, the protected areas may have been designated for reasons other than its vegetation e.g. birds or insects.
This study, provides some evidence that management of protected areas could be improved. However, the study has not yet looked at detailed species composition changes and how these differ between within and outside protected areas, future work hopes to study this. This may provide further insights into the benefits of protected areas and how their management could be improved. It is important that we understand how effective our protected areas are at protecting biodiversity as the Government has committed to protecting 30 % of our land and seas by 2030 as a way to halt the biodiversity crisis (a commitment called 30 by 30). This commitment is part of the current Scottish Biodiversity Strategy.
Location
DefaultProject Partners
Louise Ross, SRUC.
Related Links
Research Papers
- Climate, pollution and grazing drive long-term change in moorland habitats
- Pollution and climate change drive long-term change in Scottish wetland vegetation composition
- Biodiversity gains and losses: Evidence for homogenisation of Scottish alpine vegetation
- Long-term vegetation change in Scotland's native forests
- Decline in atmospheric sulphur deposition and changes in climate are the major drivers of long-term change in grassland plant communities in Scotland
- Forty years of change in Scottish grassland vegetation: Increased richness, decreased diversity and increased dominance
- Long-term functional structure and functional diversity changes in Scottish grasslands