The Response of Culturally Important Plants to Experimental Warming and Grazing in Pakistan Himalayas

The response of wild plants towards climate warming is taxa specific, but overgrazing could also be a determining factor for the alpine ecosystems. Overgrazing and climate warming are important drivers of alpine grassland degradation worldwide. Local indigenous peoples will be the first impacted by such degradation due to impacts on animal production and the availability of local medicinal plants. Studies on plant responses to overgrazing and climate change are rarely performed to assess threats to these biological and cultural systems. Long-term observations or manipulative experiments are promising, but rarely use strategies to evaluate the sensitivity and vulnerability of such ecosystems to climatic change. We studied the combined effects of overgrazing and increased temperatures on culturally important medicinal plants of Khunjerab National Park, Pakistan. Three experimental treatments were used (control, warming through an open-top chamber, and exclusion of grazing animals vs. the control). These experimental plots were installed at different elevations (3352-4969 m) and were monitored routinely. Grazing reduced vegetation cover & biomass by 2.3% and 6.26%, respectively, but that was not significant due to the high variability among study plots. However, warming significantly increased the overall percentage cover and biomass of all target plant species, ranging from 1±0.6% in Bistorta officinalis to 18.7 ± 4.9% in Poa alpina. Thus, warming may increase the availability of therapeutic plants for indigenous people while overgrazing would have deteriorating effects locally. This research illustrates that vegetation sensitivity to warming and overgrazing is likely to affect man– environment relationships, and traditional knowledge on a regional scale.

is well known in many regions [12,[19][20][21][22], yet detailed ethnobotanical studies are scarce [23]. 75 While a great deal of research has been conducted to predict warming and overgrazing 76 effects on alpine biodiversity, there is an important need to combine traditional indigenous 77 knowledge with modern scientific knowledge [20]. In particular, these predictions have yet to 78 incorporate perspectives that assess threats to the linked biological and cultural systems of local 79 people [24][25][26]. Here, we provide an example of integrating plant community responses to grazing 80 and warming with benefit-relevant indicators to assess how people's access to culturally important 81 plant species may be affected in the future. 82 This study was performed in Khunjerab National Park (KNP) located in the Pakistani 83 Himalayas. This region is interesting to study the combined effect of warming and grazing on Eastern Himalaya are an invaluable resource for the local communities and also Pakistan [27]. 86 Second scientists have been gathering climatic data from this remote area for over 50 years, 87 indicating that the average temperatures have increased by 1.5 ºC, more than twice the global 5 88 average increase (World Economic Forum 2020). Third, the mountainous areas of KNP are 89 extensively used as feeding grounds for both wild ungulates (yaks) and domestic animals (goats, 90 sheep, and cattle) with most families keep mixed herds [29]. Livestock pressure is progressing as 91 the human population is growing as animal production is the primary means of productivity. reliance on rangelands has placed immense burden on the highland rangelands [38].

119
The HKH region harbors a rich indigenous knowledge which serves as a source of 120 sustainable rangeland management [24]. The region is also home to the most versatile cultures,

148
The OTCs were kept on the subplots in each summer season. The warming effect of OTC at 10 149 cm above the soil surface was between 1.7-2.3°C on average. All recordings of plant community 150 composition and abundance were performed during the peak blooming season (Fig 1d)    and sampled carefully for taxonomic classification (Fig 1f). Inventory was updated each year to 9 178 record the new observations (2016-2018). We clipped the vegetation from OTC and the above-179 ground biomass of the plant species was measured by air drying samples at 37°C for 72 hours. 180 We conducted one-way ANOVA to examine the difference between percentage cover and 181 biomass of plant species under warming and grazing treatments. A Post-hoc Tukey test was applied 182 to compare the responses of plant species to a specific treatment (S3 Table a&b Bray-Curtis dissimilarity measure to deal with relative abundance data as it allows using both 188 presence/absence and abundance data. The vegan package R (metaMDS) was used for analysis.

189
All data analyses were carried out using R version 3.5.3 (2019).  We interviewed a total of 80 informants who identified approximately 50 medicinal plant species 202 widely spread in the area (see supplementary S1 Table). Those interviews also allowed us to collect 203 detailed information about the therapeutic properties of plant species along with their altitudinal 204 range of occurrence, time of blooming, part used for remedies, and potential climate change effect 205 on their availability (Table 1). Overall, people use plants to treat various diseases such as high 206 blood pressure, stomachache, wounds, cold/fever, rheumatism, asthma, diarrhea, hepatitis, and 207 diabetes (see supplementary S1 Fig.). based on the collected information, we screened out 17 highly important and common plant 214 species, which we categorized based on their percentage of use (Fig. 2). Artemisia. rupestris (AR) 215 was the most cited plant due to its availability and medicinal potential. Other widely cited plant 216 genera include Poa alpina (PA) and Oxytropis glabra (OX). significantly in warmed plots, on average by 5.5% as compared to control plots (Fig 3b, S3 Table   235 b). Plant cover increase in response to warming was highly variable among taxa, ranging from 1 ± 236 0.6% for Bistorta officinalis to 18.7 ± 4.2% for P. alpina (Fig 3b). Overall, our NMDS analysis 237 revealed that plant communities showed higher differences among sites than among warming 238 treatments, reinforcing the idea that plant response was dependent on altitude (see supplementary 239 S2 Fig.).

240
Compared to the control plots, grazing treatments had an overall negative effect on plant biomass 241 and percentage cover (Fig 3c & 3d). Yet, once again, this general trend was not significant due to 242 the high variability in plant response among sites. The extent of increase ranged from 0.1 ± 0.5%

243
in Carex divisa to 4.14 ± 1.04 % in A. rupestris. grazing (-W, -G) and antagonistic effects (-W, +G or +W, -G) (Fig 4, Table 1). The mean 264 percentage cover of species was affected positively by warming and negatively by grazing (Fig 4, 265 +W, -G zone). One species, A. rupestris, was favored by both warming and grazing. However, for 266 P. alpina and P. hololeuca, increased in cover as a response to warming at some sites made them 267 more susceptible to grazing. P. macrophylla did not show any significant response to either grazing 268 or warming except at one site (aggressively grazed) where it was negatively affected by both 269 treatments (Fig 4).  We are highly thankful to local influential persons, hunters, and guides who facilitated and 341 supported the survey team. The English language of the manuscript has been improved by Prof.

342
Dr. Richard Goodman which is acknowledged.  Competing interests 351 The authors declare that the research was conducted in the absence of any commercial or financial 352 relationships that could be construed as a potential conflict of interest.