Vegetation Pattern and Regeneration Dynamics of the Progressively Declining Monotheca buxifolia Forests in Pakistan: Implications for Conservation

Abstract

Monotheca buxifolia (Falc.) A. DC., a wild edible fruit-yielding tree species, has economic and ecological importance, yet there is a lack of studies concerning its distribution pattern and regeneration dynamics at a larger-scale. This study aims to produce the first country-level classification of Monotheca forests based on their unique floristic composition and influential abiotic factors, besides their natural regeneration dynamics, across the environmentally diverse landscapes in Pakistan. For this purpose, floristic inventory was carried out in 440 plots where environmental variables, stand dendrometric characteristics and woody-species regeneration were recorded. During this survey, 3789 individuals of 27 woody tree species belonging to 25 genera and 22 families were sampled. These native and exotic tree species were mostly dicot (73%) with predominately mega-phanerophytic (88%) lifeforms, which largely reflect strong chorological differentiation and distinct linkage (55%) to the Sino-Japanese phytogeographical region. M. buxifolia and co-occurring species exhibiting similar environmental affinities were grouped into four ecologically distinct communities by Ward’s cluster analysis. Ordinations further highlight the special effects of topographic and edaphic factors besides anthropogenic interference on the sampled plots. Generally, Monotheca stands were moderately dense, with the average density varying considerably, ranging from 296 to 325 individuals/ha, with basal area ranging from 41.26 to 93.35 m2 ha−1. In the understory stratum, natural regeneration of Monotheca was mostly scant and mainly covered by Dodonaea shrubs. Size class structure of the dominant species shows pronounced effect of anthropogenic intervention as reflected by the presence of fewer individuals of juveniles and larger trees. Overall, the cut stump frequency was higher at juvenile and mature stages, which may be attributed to over-harvesting and extraction of fuelwood apart from the adverse effect of climate change in the region. We concluded that both topographic and edaphic factors coupled with biotic interventions are more influential in the distribution and persistence of M. buxifolia and co-occurring woody species and might be considered in its restoration and conservation. Thus, we recommend an urgent management plan to favor Monotheca regeneration for allowing the renewal of these rapidly declining remnant stands in Pakistan.

Do environmental variables and overstory communities affect the spatial pattern of understory vegetation? Lessons from Monotheca buxifolia (Falc.) A. DC. forests in Pakistan

“…After several comparisons, we chose the Hellinger transformation followed by an RDA and the most significant variables were determined by using the method Wilk's lambda (De Sá 2007;Jones et al 2008). Finally, four pre-defined vegetation groups (Ali et al 2022b) obtained from Ward's agglomerative clustering techniques were used because they inherit major ecological information and were easily interpretable.…”

“…bulk density and soil slope potentially affect the understory vegetation composition (Echiverri & Macdonald 2020;Piazza et al 2016). In the northern areas of Pakistan, species richness was highly influenced by slope and altitude (Ali et al 2022b;Ullah et al 2020;Qureshi & Bhatti 2010). Variability of environmental conditions plays an important role in spatial segregation of the flora and structural variations in plant communities (Aikens et al 2007;Huo et al 2015;Dölle et al 2017).…”

“…The hotspot flora of the studied area is distributed in thirteen natural regions i.e., Alpine pastures to Mangroves, where the endangered flora is >10 % (Shinwari 2011). M. buxifolia forests are generally distributed at diverse elevation ranges and are often found toward the north and west of the country (Ali et al 2022b).…”

Ecosystem Services and Linkages of Naturally Managed Monotheca buxifolia (Falc.) A. DC. Forests with Local Communities across Contiguous Mountainous Ranges in Pakistan

“…So far, they have only been reported in some areas of Pakistan, Afghanistan, Oman, and Saudi Arabia [ 4 ]. Monotheca phytocoenoses located in the Hindu Kush and Suleiman Mountain peaks of Pakistan are facing a huge pressure from natural and anthropogenic interference [ 17 ]. These habitats are highly involved in providing several ecosystem services (fruit, timber, shelter) to local inhabitants due to constant economic crises [ 18 ].…”

“…Plant species valued for their characteristics and services have long been considered a gift from the creator, one that should be managed with special care [ 19 ]. Both the canopy species and understory vegetation of Monotheca phytocoenosis provide fruits, food, fodder, traditional medicines, and spots for tourism [ 17 ]. Monotheca , along with their associates, are very important for mountain communities as they are symbols of culture and religious belief and are actively included in ceremonies, customs, and culinary traditions [ 20 ].…”