Joseph Douglas Mandla White

Background: Ex situ conservation provides an alternative to safeguarding plant diversity. To guide future conservation strategies, a prioritisation methodology is needed, especially for the Sonoran Desert (SD), a priority arid ecoregion from Mexico and the United States. Questions and Hypotheses: What are the priority species for seed collection in the SD? What are the appropriate geographic areas for planning seed collection? We hypothesise that species with restricted distributions, higher risk of extinction, and limited representation in seed banks will have higher priority and that their distributions will coincide with the SD's areas of endemism. Studied species: Native flora of the Sonoran Desert. Study site and dates: Sonoran Desert, 2023-2025. Methods: We designed a prioritisation methodology integrating data on endemism, conservation status, storage behaviour, utilisation, presence in protected areas, and seed bank accessions status to calculate a species-level priority score. We ranked the native flora and coupled it with species distribution modelling to identifycollection focal regions. Results: We found that only 1,441 of 4,029 native taxa have any seed bank accessions. We delimited a 100-species ranking as the top priorities for seed bank preservation and defined the Baja California Peninsula as a focal point for future collections. Conclusions: Despite only one-third of the SD flora having ex situ seed collections, promisingly, more than 80 % of its flora can be cost-effectively stored. This study offers a replicable and practical framework for prioritising taxa for ex situconservation in any region, contributing to global biodiversity preservation efforts.

Achieving global biodiversity targets, such as the commitment to conserve 30% of the planet by 2030, depends on the ability of individual countries to translate targets into reality. While there has long been recognition that protected areas can bring costs as well as benefits, the implications of this for delivery of global targets have not been fully explored. We focus on Ethiopia, a country supporting globally important biodiversity but facing substantial poverty challenges. We characterize the extent and representativeness of Ethiopia’s protected area network, demonstrating that a threefold expansion—particularly into ecoregions with higher opportunity cost—would be required to meet the Kunming–Montreal Global Biodiversity Framework Target 3. Using a quasi-experimental approach (accounting for known confounders and exploring sensitivity to potential unobserved confounders), we show that the existing protected area network has reduced forest loss and agricultural expansion, and helped to maintain grasslands. Yet, this has brought social wellbeing costs equivalent to 3.9 million fewer household-months of adequate food. Surveys show that national conservation stakeholders recognize these challenges and prioritize improving effectiveness of the existing network over expansion. Our findings highlight that trade-offs between environmental and social outcomes are not simply challenges to be managed, but are central to whether global biodiversity commitments can be delivered.

Plant biodiversity is under threat. With two out of five plants at risk of extinction, preserving taxa through ex situ conservation approaches must be considered a priority. The Sonoran Desert (SD), a highly biodiverse ecoregion shared between Mexico and the United States is home to over 4000 native plant taxa. A method to determine conservation priorities was developed in collaboration with institutions from both countries. Herbaria records and data from nine seed banks were analysed to identify gaps in previous conservation efforts. The SD native taxa were prioritised based on a Priority Score (PS) and their potential distribution was modelled to identify priority regions. 4029 native taxa were reported. 1441 have accessions preserved in seed banks, but only 412 have been collected inside the SD. The PS considers some potentially endemic (126) and threatened taxa (112) as the most urgent to preserve. It also includes information about the storage behaviour (3236 orthodox), useful plants (1406), and taxa without populations in protected areas (230) to categorise the species. Although most of the SD flora is not represented in seed banks, at least 80% is predicted to produce desiccation-tolerant seeds and thus can be cost-effectively stored. Spatial analysis shows that the central region of the Baja California Peninsula stands out for its species richness and endemism. Our study presents the first ex situ conservation gap analysis of the SD flora and provides a replicable methodology for identifying priority species and potential areas for ex situ collection.

Grassy ecosystems cover more than 40% of the world's terrestrial surface, supporting crucial ecosystem services and unique biodiversity. These ecosystems have experienced major losses from conversion to agriculture with the remaining fragments threatened by global change. Woody plant encroachment, the increase in woody cover threatening grassy ecosystems, is a major global change symptom, shifting the composition, structure, and function of plant communities with concomitant effects on all biodiversity. To identify generalisable impacts of encroachment on biodiversity, we urgently need broad‐scale studies on how species respond to woody cover change. Here, we make use of bird atlas, woody cover change data (between 2007 and 2016) and species traits, to assess: (1) population trends and woody cover responses using dynamic occupancy models; (2) how outcomes relate to habitat, diet and nesting traits; and (3) predictions of future occupancy trends, for 191 abundant, southern African bird species. We found that: (1) 63% (121) of species showed a decline in occupancy, with 18% (34) of species' declines correlated with increasing woody cover (i.e. losers). Only 2% (4) of species showed increasing population trends linked with increased woody cover (i.e. winners); (2) Open habitat specialist, invertivorous, ground nesting birds were the most frequent losers, however, we found no definitive evidence that the selected traits could predict outcomes; and (3) We predict open habitat loser species will take on average 52 years to experience 50% population declines with current rates of encroachment. Our results bring attention to concerning region‐wide declining bird population trends and highlight woody plant encroachment as an important driver of bird population dynamics. Importantly, these findings should encourage improved management and restoration of our remaining grassy ecosystems. Furthermore, our findings show the importance of lands beyond protected areas for biodiversity, and the urgent need to mitigate the impacts of woody plant encroachment on bird biodiversity.

Grasslands were often viewed as successional vegetation, a precursor to a possible forest, and were thought to have low diversity. However, a growing number of research projects have shown that these ecosystems boast high biodiversity and massive carbon storing potential, and require at least a century to recover after agricultural ploughing which severely disrupts the environment and consequently lowers plant diversity and carbon stocks. Conserving natural grasslands should be prioritised, as they provide us with important ecosystem services beneficial to not only natural systems, but also the longevity of humans through food security and buffering of the effects of climate change.

Woody‐plant encroachment is an under‐recognized consequence of land degradation. This phenomenon is common in rangeland ecosystems, where woody plants outcompete grasses, resulting in a shift to more wooded ecosystems. The consequences of this for livelihoods are most often damaging. Case studies at a local scale have shown negative consequences for ecosystem services and livelihoods, though few have considered these impacts over greater scales to find more generalizable patterns that are useful for governance structures at actionable levels. Here we make use of census data on household income and use of provisioning ecosystem services together with remote‐sensed woody‐plant encroachment data to perform the first country‐wide assessment at the municipal level across South Africa investigating correlations between woody cover change and (1) household income and (2) the use of provisioning ecosystem services use. We show that woody‐plant encroachment is greatest in municipalities with low income and a higher reliance on provisioning ecosystem services, specifically when woody cover was low. This reinforces a poverty trap by creating a positive‐feedback loop. For example, encroached landscapes with lower grass cover are more prone to overgrazing, decreasing fuel loads and further driving encroachment. This places more pressure on the remaining grass cover and decreases the provisioning of ecosystem services. Furthermore, our results allow us to rank the most affected municipalities based on income, reliance on provisioning ecosystem services and rates of woody cover change. We identify 16 municipalities requiring much‐needed interventions due to the risk of woody‐plant encroachment to natural resource‐reliant livelihoods. We suggest that interventions to reduce woody‐plant encroachment be targeted in low‐income communities, providing a win–win scenario for livelihoods and biodiversity. We recommend that woody‐plant encroachment be recognized as major form of land degradation and that restoration of encroached landscapes be prioritized within the UN Decade of Ecological Restoration 2021–2030. Read the free Plain Language Summary for this article on the Journal blog.

Some rodents gather and store seeds. How many seeds they gather and how they treat those seeds is largely determined by seed traits such as mass, nutrient content, hardness of the seed coat, presence of secondary compounds, and germination schedule. Through their consumption and dispersal of seeds, rodents act as agents of natural selection on seed traits, and those traits influence how rodents forage. Many seeds that are scatter‐hoarded by rodents are pilfered, or stolen, by other rodents, and seed traits also likely influence pilfering rates and seed fates of pilfered seeds. To clarify coevolutionary relationships between rodents and the plants that they disperse, one needs to understand the role of seed traits in rodent foraging decisions. We compared how the seeds of 4 species of plants that are dispersed by scatter‐hoarding animals and that differ in value (singleleaf piñon pine, Pinus monophylla; desert peach, Prunus andersonii; antelope bitterbrush, Purshia tridentata; Utah juniper, Juniperus osteosperma) were pilfered and recached by rodents. One hundred artificial caches of the 4 seed species (25 per species) were prepared, and removal by rodents was monitored. Rodents pilfered high‐value seeds more rapidly than the other seeds. Desert peach seeds, which contain toxic secondary compounds, were more frequently recached. Relatively low value seeds like Utah juniper and antelope bitterbrush were pilfered more slowly and were sometimes left at cache sites, and seeds of the latter species were transported shorter distances to new cache sites. The background density of seeds also appeared to influence the relative value of seeds.