Plant Species Diversity and Conservation

1. Introduction

Current estimates indicate that the global terrestrial flora comprises approximately 500,000 plant species [1,2], exceeding the diversity documented for birds and mammals and surpassed only by fungi and beetles. Plant species diversity constitutes a fundamental component of terrestrial ecosystems, playing a critical role in the maintenance of ecosystem functioning, ecological stability, and biosphere sustainability [3]. Defined as the richness and relative abundance of plant taxa within a given area, plant diversity represents a key determinant of ecosystem resilience and adaptive capacity. Plant communities characterized by high levels of species diversity are generally more resistant to environmental disturbances, including extreme climatic events, pathogen outbreaks, and biological invasions. Moreover, they contribute substantially to the provision of essential ecosystem services, such as soil stabilization, water purification, nutrient cycling, and carbon sequestration [3].

2. An Overview of Published Articles

In this context, the conservation of plant diversity [4] necessitates coordinated actions at local [5], national, and global scales, including the protection and restoration of natural habitats [6,7], the implementation of sustainable land-use practices, and the effective management of invasive species. Such measures are essential for ensuring the persistence of plant diversity and the maintenance of ecosystem functions under ongoing environmental change [8,9].

Laface et al. [4] focused on the southern sector of the Metropolitan City of Reggio Calabria and the Aspromonte massif and described four orchid hybrids new to science, all assessed as Critically Endangered (CR). Additionally, two hybrids newly recorded for the Calabrian flora were also evaluated as CR. The research confirmed historical occurrences of Ophrys speculum and identified the southernmost continental Italian populations of both Ophrys speculum and Orchis branciforti. These findings substantially improve current knowledge of orchid diversity and conservation in Southern Italy. Another rare plant species, Leontopodium alpinum, globally protected but of pharmaceutical and cosmetic importance was studied by Negru et al. [5]. The authors demonstrated that ex situ cultivation under controlled conditions maintains the species’ morphological and physiological stability, supporting its potential for conservation and sustainable commercial cultivation.

Moreover, Banaszczyk et al. [9] analyzed ex situ tissue culture collections, representing an important tool for the conservation of rare and endangered plant species. Their study reviewed micropropagation research on coastal plant species of the Baltic Sea region, covering 25 families and 112 highly coastal-specific taxa. The analysis revealed that tissue culture protocols are currently available for only 38 species (34% of the target taxa), indicating substantial knowledge gaps. The authors highlighted several priority taxa for future research and emphasized the need to develop ecologically relevant and practically applicable micropropagation protocols to support conservation, habitat restoration, and potential commercial use.

In contrast, Boubekraoui et al. [8] evaluated the conservation effectiveness of 21 protected areas in Northern Morocco against five major landscape pressures: deforestation, infrastructure expansion, agricultural intensification, fires, and population growth. Using remote sensing data and spatial analysis, a cumulative effect index was developed to assess human pressures and conservation performance. Results showed that wildfire represented the main driver of forest loss within protected areas and that disturbance levels were often similar inside and outside protected zones. Nevertheless, national parks with stronger protection regimes exhibited lower levels of degradation.

The study also proposed a transferable methodological framework for assessing protected-area effectiveness in other regions. At the same time, Aragón-Gastélum et al. [6] showed that approximately 80% of species will experience shifts in suitable habitats, with greater habitat loss projected under the SSP585 scenario. The authors used ecological niche models for 92 species under current conditions and future climate scenarios (SSP245 and SSP585, 2041–2060) for the study. Although overall species richness may slightly increase, areas of high richness are predicted to contract markedly under severe climate conditions, while low-richness areas expand. These findings provide important baseline information for biodiversity conservation, habitat management, and species selection in ecological restoration and reforestation programs.

Finally, in the Piatra Craiului National Park, Carpathian Mountains, Biță-Nicolae et al. [7] found 731 vascular plant species, including 35 Carpathian endemics and 18 species of conservation interest. Endemic taxa were mainly associated with high-altitude calcareous rocky and grassland habitats, showing maximum diversity at 1600–1700 m altitude. Their distribution was strongly influenced by altitude, habitat type, and environmental conditions. Although these endemic species are not directly protected by national legislation, their habitats are included within strictly protected areas of the national park and the Natura 2000 site ROSAC0194 Piatra Craiului.

3. Conclusions

During recent decades, anthropogenic pressures have resulted in a marked decline in plant diversity at regional and global scales. Habitat loss, fragmentation, and degradation, together with overexploitation of natural resources, environmental pollution, invasive alien species, and climate change, are recognized among the principal drivers of biodiversity erosion. Despite its ecological and functional importance, plant species diversity remains increasingly threatened by these interacting factors, with significant implications for ecosystem integrity and long-term environmental sustainability.

Taken together, the studies presented in this issue highlight not only the extraordinary diversity and vulnerability of plant species and habitats, but also the pressing need for coordinated scientific, conservation, and management efforts to ensure their persistence under accelerating environmental change.