Sarah Lou Malick-Wahls

• Malick-Wahls, Sarah Lou; Devineau, Olivier; Zimmermann, Barbara & Tofastrud, Morten (2026). Finding common ground in commercial forests: Sheep grazing, timber production, and carnivore fences. Forest Ecology and Management. ISSN 0378-1127. 609. doi: 10.1016/j.foreco.2026.123663. Full text in Research Archive Show summary

  Sheep (Ovis aries Linnaeus, 1758) grazing has the potential for positive impacts on commercial forestry through weeding competing plants, or to be detrimental if browsing and trampling levels are high. In some regions of Norway, large, forested areas are fenced to minimize depredation risk from recovering carnivore populations on unsupervised sheep, but fences may alter the behavior of sheep leading to differential effects inside and outside of these fences. We estimated Norway spruce (Picea abies (Karst.) L.) sapling growth and frequency of damage in Inland and Trøndelag counties Norway, and related these to grazing intensity, fenced status, and competing vegetation along 70 transects within 8 fenced and 11 unfenced clearcuts during August 2024. We found that growth of terminal leaders decreased with increasing grazing intensity inside fences, whereas growth increased along with grazing intensity outside fences. Sheep grazing in our study had a positive effect on spruce sapling growth form by decreasing slenderness, measured by height-to-diameter ratio, both inside and outside fences. While less than three percent of saplings were browsed overall, browsing of saplings did increase at higher grazing intensities. Trampling was negligible on all transects. Our results suggest that sheep grazing is compatible with spruce regeneration and carnivore fencing as negative impacts from increasing amounts of sheep resulting in reduced growth of terminal leaders may have been offset by decreasing height-to-diameter ratios. Lower height-to-diameter ratios suggest more resilient saplings that could make them better able to withstand stressors. However, if sheep are allowed to reach high grazing intensities, this balance may not be achieved as browsing increases. With increasing demands on forested landscapes, integrating sheep grazing in carnivore-resistant fences on commercial forests presents an opportunity for multiple-use land management with minimal associated trade-offs.

• Malick-Wahls, Sarah Lou; Høydal, Silje Maria Midthjell; Devineau, Olivier & Tofastrud, Morten (2026). Declining bumblebee (Bombus) species richness and abundance with increasing sheep grazing intensity on traditional Norwegian summer farms. Ecological Solutions and Evidence. 7(3). doi: 10.1002/2688-8319.70288. Full text in Research Archive Show summary

  Semi‐natural grasslands are valuable habitat for bumblebees ( Bombus spp.) in Fennoscandia. These grasslands are often maintained by livestock such as free‐ranging sheep, but it is unclear if sheep grazing impacts bumblebee communities, and if so, which grazing intensity is best. We compared bumblebee species richness and abundance on semi‐natural grasslands in southeastern Norway at varying levels of disturbance by sheep (0–1680 initially released). We used Bayesian hierarchical models to test the intermediate disturbance hypothesis, that the highest bumblebee abundance and richness would occur at moderate grazing intensity, while considering other important habitat variables: distance to forest, meadow size, sward height, and availability of flowers, litter, and bare soil. We found no support for the intermediate disturbance hypothesis but rather a negative relationship between the number of sheep released and measures of bumblebee species richness and abundance from targeted netting. Effects varied among the most common species. B. pratorum and B. wurflenii were more sensitive to the number of sheep released than were B. jonellus . Bumblebee abundance estimated by two capture methods (blue vane trapping and targeted netting) was only weakly correlated and bumblebee species richness estimated from traps was unrelated to any of our predictor variables. Practical implication . Our results suggest a weak negative influence of any amount of sheep grazing on bumblebee abundance and richness. Targeted netting was a more reliable method than blue vane traps to assess effects on the bumblebee community.

• Malick-Wahls, Sarah Lou; Høydal, Silje Maria Midthjell; Devineau, Olivier & Tofastrud, Morten (2025). Optimal sheep grazing intensity for bumblebee Bombus species richness and abundance on traditional Norwegian summer farms. Ecological Solutions and Evidence. 6(2). doi: 10.1002/2688-8319.70054. Full text in Research Archive Show summary

  1. Semi‐natural grasslands are recognized as important habitat for bumblebees in Fennoscandia. These grasslands are maintained by free‐ranging sheep, but it is unclear which sheep intensities are most beneficial to bumblebees. 2. We will compare bumblebee species richness and abundance with Bayesian mixed models at varying levels of disturbance by sheep to test the Intermediate Disturbance Hypothesis, while considering other important habitat variables: distance to forest, meadow size, sward height, and availability of flowers, litter and bare soil. 3. Practical Implication: Results of this investigation will provide valuable information to land managers setting limits for the number of free‐ranging sheep released on semi‐natural grasslands within the coniferous boreal landscape to benefit bumblebee conservation.

• Malick-Wahls, Sarah Lou; Byrkjedal, Ingvar; Ganter, Barbara; Lifjeld, Jan Terje; Marthinsen, Gunnhild & Rösner, Hans-Ulrich [Show all 7 contributors for this article] (2024). Morphometric differences between sexes and populations in Norwegian Dunlins Calidris alpina. Bird Study. ISSN 0006-3657. doi: 10.1080/00063657.2024.2392214. Full text in Research Archive Show summary

  Capsule The sex of Dunlins from two widely separated Norwegian breeding populations can be determined using morphometrics, with the Dunlins’ sizes differing between populations. Aims We aimed to understand the Dunlin’s physical characteristics within and outside of a zone of intergradation between the subspecies C. a. schinzii and C. a. alpina, and to provide a resource for determining the sexes. Methods We tested for morphometric differences between Dunlins from Finnmark, inland South Norway and coastal South Norway to determine if any or all of these populations had unique characteristics. We also compared morphometrics from our study with those in published sources. We performed discriminant function analyses on morphometric data from Dunlins of known sex to identify variables that could be used for sex identification in captured birds. Results Dunlins from Finnmark were significantly larger than those from South Norway. However, birds from inland South Norway, and a small sample from coastal South Norway, overlapped in multiple measurements. Our comparison with previously published sources also found no clear differences in morphometrics between birds from South Norway and C. a. schinzii from other populations. Our discriminant functions for both Finnmark and inland South Norway accurately predicted the sex of Dunlins using only the wing chord and bill length measurements. Conclusion There was no clear evidence that Dunlins from the subspecies intergradation zone in South Norway differed in size from subspecies C. a. schinzii. The sex of Norwegian-breeding Dunlins can be accurately determined by morphometrics alone, using population-specific discriminant functions.

• Hostetter, Nathan; Ryan, Dan; Grosshuesch, Dave; Catton, Tim; Malick-Wahls, Sarah Lou & Smith, Tam [Show all 7 contributors for this article] (2020). Quantifying spatiotemporal occupancy dynamics and multi-year core-use areas at a species range boundary. Diversity and Distributions: A Journal of Conservation Biogeography. ISSN 1366-9516. 26, p. 795–805. Full text in Research Archive
• Barber-Meyer, Shannon; Ryan, Dan; Grosshuesch, Dave; Catton, Tim & Malick-Wahls, Sarah Lou (2018). Use of non-invasive genetics to generate core-area population estimates of a threatened predator in the Superior National Forest, USA. Canadian Wildlife Biology & Management. 7, p. 46–55. Full text in Research Archive
• Malick-Wahls, Sarah Lou; Bruggink, John & Belant, Jerrold (2012). Effects of Forest Patch Characteristics on Small Mammal Species Composition, Grand Sable Dunes, Michigan. Natural areas journal. ISSN 0885-8608. 32, p. 293–299. Full text in Research Archive
• Malick-Wahls, Sarah Lou; Bruggink, John & Belant, Jerrold L. (2012). Influence of Spotted Knapweed on Diversity and Abundance of Small Mammals in Grand Sable Dunes, Michigan. Natural areas journal. ISSN 0885-8608. 32, p. 398–402. Full text in Research Archive

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• Spedener, Mélanie; Austrheim, Gunnar; Goudier, Alexandre; Hauer, Josh; Helbert, Juliette & Henriksen, Marie Vestergaard [Show all 16 contributors for this article] (2025). Husdyr på skogsbeite: Påvirkninger på granforyngelse og plante-pollinator-samfunn. Universitetet i Innlandet. ISSN 9788283805871. Full text in Research Archive Show summary

  Diskusjonen om husdyr på utmarksbeite i skog er sammensatt og går blant annet ut på hvordan det kan kombineres med skogdrift, rovviltforvaltning, og bevaring av biologisk mangfold. I dette forskningsprosjektet har vi undersøkt hvordan husdyr på sommerbeite i skog innenfor eller nær ulvesonen påvirker skogbruk og artsmangfold. Nærmere bestemt har vi studert effektene av sau innenfor rovviltavvisende gjerder og av frittgående storfe på granforyngelse og plante-pollinator samfunn i boreal produksjonsskog. Vi undersøkte hvorvidt beitedyrene gjorde skade på unge grantrær gjennom beiting og tråkk og hvorvidt de bidro til ungskogspleie ved å fjerne konkurrerende vegetasjon. I tillegg undersøkte vi hvordan beitedyr påvirket planter i feltsjiktet, blomsterressurser og pollinerende insekter. Hverken storfe eller sau førte til økte beite- og tråkkeskader på små grantrær. Både storfe og sau bidro til ungskogspleie ved å beite på løvtrær og ved å redusere høyden av feltsjiktvegetasjonen. Storfe førte til økt dødelighet hos gran, om så i svært begrenset omfang, mens sau førte til økt høydetilvekst. Både storfe og sau påvirket feltsjiktvegetasjonen, men storfe i større grad enn sau. Sau førte til redusert høyde av graminider, mens storfe førte til redusert høyde av graminider, lyng og urter, i tillegg til redusert mengde av graminider. Både storfe og sau påvirket blomsterressursene, og storfe hadde igjen større effekt enn sau. Mens sau førte til en nedgang i artsrikdom, førte storfe til nedgang i både artsrikdom og mengde av blomster. Både storfe og sau påvirket pollinerende insekter, og her førte begge til en nedgang i mengden av disse. Funnene våre tilsier at både sau innenfor rovviltavvisende gjerder og frittgående storfe godt kan kombineres med dagens skogbruk som har som hovedmål å produsere grantømmer ved bruk av flatehogst – i hvert fall når husdyrtetthetene er like lave som i våre studieområder. Vi var overrasket over at husdyrene hadde negative effekter på plante-pollinator samfunn. Dette er bekymringsfullt og bør tas hensyn til, særlig siden vi nesten utelukkende fant ville pollinatorer i studieområdene våre, som er av stor interesse i forhold til naturvern.

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