**3. Results**

Results contained the development of all livestock units (LSU) from 1929 to 2016 in Section 3.1, th feed demand of the small ruminant population in Section 3.2, the grazing demand in comparison to the grazing capacity from 1993 to 2013 in Section 3.3, an analysis of production potentials in Section 3.4, and the assessment of the monetary economy of the small ruminant farming system (SRFS) in Section 3.5.

#### *3.1. Development of the Total Livestock Units on Samothrace 1929–2016*

Figure 4 shows the increasing significance of small ruminants in relation to other livestock species on the island from 1929 to 2016. Total livestock is expressed in livestock units (LSU), which express the nutritional requirements of each species. In 1929, the island had 490 [LSU] cows, 430 [LSU] pigs, 1250 [LSU] Equidae (horses, mules and donkeys), 3026 [LSU] poultry, 1672 [LSU] sheep and 2892 [LSU] goats. Small ruminants represented only 21% of all [LSU] in 1929, compared to cows (22%), pigs (10%), Equidae (45%) and poultry (2%). In 2016, small ruminants represented 93% of all LSU (2276 [LSU] sheep; 2428 [LSU] goats), while cows are reduced to 0%, pigs to 5% (277 [LSU]), Equidae to 1% (56 [LSU]) and poultry remained at 2% (77 [LSU]). Total [LSU] for small ruminants increased from 456 in 1929 to 4478 in 1992 before reaching their peak at 6735 in 2002, declining to values between 4100 and 4800 thereafter. For annual population numbers and [LSU] refer to Supplementary Data: Figure S4.

**Figure 4.** Development of total livestock units [LSU] on Samothrace from 1929 to 2016.

#### *3.2. The Metabolism of the Small Ruminant Population of Samothrace 1993–2016*

Figure 5 shows the annual feed demand of the small ruminant population in 5 categories: imported feed (orange), locally produced feed (dark yellow), crop residues (yellow), leaves (dark green) and fresh grass (green). Total feed demand was 23,000 tDM/year in 1993, increased to 31,600 tDM/year in 2001, and declined to values between 19,000 and 21,000 tDM/year thereafter. Annual values are provided in Supplementary Data: Figure S5.

**Figure 5.** Annual feed demand of the small ruminant population in tons of dry mass (DM) from 1993 to 2016.

#### *3.3. Utilization of Grazing Resources by the Small Ruminant Population*

Grazing in local ecosystems accounts for the feed demand categories of fresh grass, leaves and crop residues (Figure 6). In 1993, the grazing demand of the small ruminant population was 9900 tC/year, increasing to 13,700 tC/year in 2001, and declining to values between 7000 and 8000 tC/year thereafter. Herein, we use two boundaries of the net primary production of biomass available for grazing (NPP) to assess the potential overgrazing and therefore, degradation of local ecosystems (see Section 2.3.2). We found that the upper grazing boundary was exceeded for at least 10 years between 1995 and 2005, while the lower boundary was exceeded for almost the entire period.

**Figure 6.** Grazing balance for the small ruminant population in annual tons of carbon (C) from 1993 to 2016. Annual values are provided in Supplementary Data: Figure S5.

#### *3.4. The (Under-)Utilization of Production Potentials*

Figure 7 shows the difference between modelled potential and official production numbers between 1993 and 2016, derived from statistical data. Official production of milk (blue solid line) and meat (red solid line) are far below the potential production (dashed lines and standard deviation bars of same color) for the entire period. For the entire period, farmers produced 74% (milk) and 61% (meat) below the modelled production potentials. While potential milk production increases with the population increase from 4800 <sup>t</sup>/year in 1993 to 6600 <sup>t</sup>/year in 2002, official production declines from 1330 <sup>t</sup>/year to 806 <sup>t</sup>/year. The increase of the official milk production after 2003 can most likely be attributed to the reopening of the local dairy. Annual values are provided in Supplementary Data: Figure S7.

#### *3.5. The Monetary Economy of the Small Ruminant Farming System in 2016*

Figure 8 plots revenue against cost to estimate the annual income for the entire small ruminant farming system (SRFS) and the average farmer. 171 small ruminant farmers generated a revenue of 4.2 million €/year through milk and milk products, meat and subsidies in 2016. Costs for farm utility, processing, transport, land and animal maintenance were 3.4 million €/year, resulting in a net income of 860,000 €/year. For the single average farmer, this meant a revenue of 25,000 €/year, costs of 20,000 €/year and a net income of 5000 €/year. Values for categories are provided in Supplementary Data: Figure S8.

**Figure 8.** Annual monetary economy of the small ruminant farming system (**left**) and the average small ruminant farmer (**right**) in 2016.
