Key areas for orchid conservation in the Central Himalaya

The Orchidaceae is one of the most species-rich angiosperm families, with over 30,000 accepted species. With the exception of Antarctica, the family can be found on all continents and the majority of island groups. Orchids, like many other plant groups, face significant threats from habitat destruction and fragmentation, overharvesting, climate change, and a variety of other human-caused issues. Many countries list them as threatened plant species, and as research continues, the number of endangered orchid species on national and international lists is bound to grow. Most orchid species' threat levels are likely to rise further in the future due to their limited distributional ranges and occurrence in naturally small and isolated populations. Orchids' highly specialized pollination strategies (e.g., food and sexual deception), high pollinator specificity, and reliance on pollinators for sexual reproduction are additional factors that may push them to the brink of extinction. Macroscale studies evaluating the spatial distribution of orchids, which are critical for identifying key locations for orchid conservation, are mostly lacking in Nepal. One of the causes of this gap may be the absence of high-resolution data on orchid distribution. This data deficiency has not only limited our understanding of the factors that influence the spatial pattern of orchid distribution but also hindered the development of successful orchid conservation plans, which Nepal desperately needs.

Figure 1. Spatial patterns of (a) all, (b) common, (c) rare, (d) epiphyte and (e) terrestrial orchid species richness estimated in 10 × 10 km2 grid cell. (f) Pearson's correlation coefficient between species richness patterns of the five species groups. The significance of the correlation tests was computed using modified t-test. All correlations were statistically significant at α level 0.05.

In order to fulfill this data and knowledge gap, we built one of the most comprehensive distribution datasets for all orchid species (>500) in Nepal at a much finer spatial resolution of 10 × 10 sq. km. Using this dataset together with the environmental data estimated at the same spatial resolution and insect diversity data compiled herein, we identified the key factors driving the spatial patterns of orchid species richness. We also evaluated potential gaps in their conservation and identified critical areas for systematic conservation of orchids in Nepal. we found that the fundamental drivers underlying the richness pattern of distinct species groups also differed. For example, variables representing climate seasonality and habitat heterogeneity were consistently the most important predictors of the richness patterns of all, common and terrestrial orchids, whereas water-related variables were important in predicting the richness pattern of epiphytic orchids. These differences in the importance of predictors in explaining the richness patterns of different groups could be attributed to differences in their adaptations to varying environmental conditions. Insect diversity was the most important predictor of the richness pattern of rare orchid species and all the models consistently supported this. We identified priority locations for orchid conservation in Nepal that

account for around 3 % of the overall land area. These places are primarily found in the mid-hills and highlands of central Nepal, with the majority of them located in the mid-hills. The phi coefficient revealed that the key locations for distinct species groupings have relatively little spatial congruence. This could imply that the conservation of one species group is insufficient to assure the protection of the other. This is quite expected given that different species groupings have different ecological correlates and consequently different spatial distributions. Key areas for preserving orchid species are only very marginally covered by Nepal's protected area network. A significant number of

orchid species (101 taxa), mostly distributed in the eastern and central mid-hills, are still found outside of any protected area network. Rare and epiphyte orchids in particular have the least protection coverage overall, indicating increased vulnerability of these two groups. One of the reasons for the inadequate representation of orchid species may be the uneven distribution of protected areas in Nepal. For example, the majority of protected areas are located in the northern highlands, and the coverage of protected areas in Nepal's mid-hills and lowlands is incredibly sparse.

Figure 2. Important areas for the systematic conservation of (a) all, (b) common, (c) rare, (d) epiphyte and (e) terrestrial orchids in Nepal identified using complementarity algorithm. (f) Phi Coefficient between the spatial patterns of key areas of the five species groups. Significant associations are shown with an asterisk (*p < 0.05) next to the coefficient.

This shows that Nepal's network of protected areas is insufficient for protecting plants in general. Nepal's protected area coverage, with 23.39 % of the country's total land area, is very close to the post-2020 global biodiversity objective, which aims to conserve at least 30 % land area by 2030. This covering, though, is by no means typical for preserving plants. Therefore, concentrating primarily on percentage-based targets to increase the coverage of protected area networks is less beneficial for maintaining biodiversity in general. Assessment of whether these regions are accurately reflective of the existing biodiversity is the only way to determine whether biodiversity conservation efforts have been successful.

https://doi.org/10.1016/j.biocon.2023.110121

Conservation priorities of endemic seed plants in the Central Himalaya

Protected areas (PA) are usually designed by taking into consideration the distribution ranges of certain flagship species, particularly mammals and birds. Although plants play an essential ecological role, they are often neglected and are hardly taken as a proxy for conservation decision-making. Several studies have documented incongruences between the spatial diversity patterns of different taxonomic groups, which means that different taxa have different conservation priorities and hence, areas prioritized for one may not necessarily ensure sufficient protection to the other. Therefore, given a potential scenario of conservation bias against plants, existing PA networks may be largely insufficient in protecting them. This emphasizes the need to reevaluate the representation of plants in existing PA networks and identify potential gaps in their conservation.

Globally, there are many cases where PAs are established in sites that are either unimportant to biodiversity or have the lowest conservation need. For example, areas that are economically less promising for alternate land use are usually selected for PA establishment due to ease in acquiring such lands. Such PAs not only fail to capture biodiversity but also cause considerable misallocation of conservation resources. In order to achieve maximum conservation benefit, the prioritized areas must be fully representative of the extant biodiversity. Such maximal representation of biodiversity can be achieved by systematically identifying sites of high conservation importance and establishing PAs in thus prioritized sites.

Figure 1. Sites of complementary (a) species richness, (b) weighted endemism, (c) phylogenetic diversity and (d) phylogenetic endemism of endemic seed plants in Nepal identified by complementarity algorithm.

In the current study, we built one of the most comprehensive distribution datasets for the entire endemic seed plants (316 species) in the central Himalaya (Nepal) at a much finer spatial resolution (10 × 10 km2) to bridge the existing knowledge gap on the status of plant protection. Using this dataset and the largest time-calibrated phylogeny of global seed plants, we identified key areas for the systematic protection of species and evolutionary diversity of endemic seed plants in Nepal. Our assessment identified a total of 47 grid cells as priority sites for conserving overall species and evolutionary diversity of endemic seed plants. Interestingly, more than half of these priority grid cells (26 grid cells) were outside the existing protected area network, which shows a weak protection status of endemic seed plants in Nepal. Furthermore, we found that the mean range size of species in unprotected grid cells was significantly lower (F (1, 342) = 30.99; p < 0.001) than that of the species in protected grid cells.

Figure 2. Priority areas for systematic conservation of species and evolutionary diversity of endemic seed plants in Nepal and the gaps in conservation. Sites within and outside the protected area networks are shown in blue and red color, respectively.

Unlike the commonly used hotspot approach, which puts more emphasis to species-rich areas, the priority areas identified in this study are not only species diversity hotspots but also species diversity coldspots. While preserving hotspots would undoubtedly protect a large fraction of biodiversity, the biodiversity coldspots may be ecologically and evolutionarily important areas offering important ecosystem services and/or sheltering unique evolutionary lineages. Therefore, such areas should not be overlooked in conservation planning. Although Nepal's PA coverage is much higher than the Aichi biodiversity target, the existing PA network in Nepal is far from being ecologically representative. This study reinforces that simply increasing the land area for protection is less meaningful to overall biodiversity conservation. Therefore, instead of focusing on increasing the percentage coverage, countries should first evaluate if the prioritized areas are truly representative of the extant biodiversity. The findings of the present study have clear conservation implications for protecting endemic seed plants in Nepal and may be used as a baseline data to identify important plant areas in Nepal. This might also be useful in selecting representative areas for expanding PA networks in Nepal to meet the post-2020 global biodiversity target.

https://www.sciencedirect.com/science/article/abs/pii/S0006320721003268

Vulnerabilities of protected lands in the face of climate and human footprint changes

Protected areas are a globally accepted strategy for lowering the extinction risks of species. They play a crucial role in minimizing habitat loss and maintaining sustainable population levels of species. Although the extent of protected areas have largely increased since the Earth Summit in 1992, they are still insufficient in addressing the current biodiversity crisis. One of the biggest challenges for expanding protected areas is to select the right areas for conservation, as studies have shown that merely fulfilling the quantitative target is less effective for overall biodiversity conservation. Additionally, human pressure and climate change are two important global challenges that pose immense threat to biodiversity. Therefore, it is imperative to consider biodiversity value (i.e. number of threatened species) within protected lands together with the dynamics of climate change and anthropogenic pressure to identify vulnerable areas that require immediate conservation attention. In order to gauze the vulnerabilities of protected lands; we developed a novel framework to quantify the level of threat in over 2500 protected areas in China incorporating three dimensions: species vulnerability, anthropogenic vulnerability and climate vulnerability. We classified these protected areas into different threat categories according to their vulnerability scores and identified areas that require the highest conservation attention.

Interestingly, the species vulnerability hotspots (SVH) were found to have higher climate change since the 1960s compared to species vulnerability coldspots (SVC), which indicates that the SVH have remained climatically unstable since the past. This is very concerning from a conservation perspective, as climate is likely to change at the observed pace. These findings suggest that habitat loss due to increased anthropogenic pressure could likely be a major threat to species in most protected areas in China. The findings have important implications for maximizing the efficiency of global protected areas in the future. The framework is also useful for evaluating the vulnerability of global protected lands and for selecting resilient areas for expanding protected areas coverage to meet the post-2020 global biodiversity target.

https://www.nature.com/articles/s41467-021-21914-w