Tetrastigma loheri (Vitaceae) is a vine species native to Borneo and the Philippines. Because it is a commonly encountered forest species in the Philippines, T. loheri is potentially suitable for studying patterns of genetic diversity and connectivity among fragmented forestecosystems in various parts of this country. However, previous research suggests that T. loheri is part of a species complex in the Philippines (i.e. the T. loheri s. l. complex) that potentially also contains Philippine plants identified as T. diepenhorstii, T. philippinense, T. stenophyllum, andT. trifoliolatum. This uncertainty about its taxonomic delimitation can make it challenging to draw conclusions that are relevant to conservation from genetic studies using this species. Here, we tested the hypothesis that T. loheri s. l. is composed of more than one species in the Philippines.For this, we used generalized mixed Yule coalescent (GMYC) and Poisson tree process (PTP) species delimitation models to identify clades within DNA sequence phylogenies of T. loheri s. l. that might constitute species within this complex. Although these methods identified several putative species, these are statistically poorly supported and subsequent random forest analyses using a geometric morphometric leafshape dataset and several other vegetative characters did not result in the identification of characters that can be used to discriminate these putative species morphologically. Furthermore, the results of principal component and principal coordinates analyses of these data suggest the absence of morphological discontinuities within the species complex. Under a unified species concept that uses phylogenetic and morphological distinction as operational criteria for species recognition, we therefore conclude that the currently available data do not support recognizing multiple species in the T. loheri s. l. complex. This implies that T. loheri is best considered as a single, morphologically variable specieswhen used for studying patterns of genetic diversity and connectivity in the Philippines.
Vaccinium cebuense (Ericaceae) from Nug-as forest (Alcoy) and the Central Cebu Protected Landscape (Balamban), two of the last remaining forested areas of Cebu Island, Philippines, is here described as a new species. This species is unique among the known species of this genus in displaying a unique combination of characters: leaves with marginal glands that are spaced along the entire length of the leaf, anthers with distinct and recurved dorsal spurs, and petioles that are adaxially grooved. Our fieldwork in Nug-as also resulted in the discovery of Phaius reflexipetalus (Orchidaceae), a new record for the Philippines previously only known from Borneo. These and other recent taxonomic novelties emphasize the conservation importance of the few and small remaining forests of Cebu.
<i>Antherostele</i> Bremek. is an understudied genus of Rubiaceae endemic to the Philippines formerly comprising four species of shrubs or small trees distributed in Luzon and Visayas. In this first molecular study of the genus, the ITS (nrDNA) was utilized to determine the monophyly of <i>Antherostele</i>, reconstruct its phylogeny, and resolve its placement in Rubiaceae. Furthermore, an update on the assessment of its conservation status of the included species in the genus was done. <i>Antherostele</i> is monophyletic and is nested within the tribe Urophylleae of subfamily Rubioideae which confirms its segregation from <i>Urophyllum</i> and its placement within Urophylleae as proposed by earlier authors based on morphology. However, the relationships of Urophylleae members remain unresolved. <i>Antherostele</i> is united by reflexed corolla, hairs on upper side of the corolla lobes and syngenesious stamens. The montane <i>A. luzoniensis</i> with small leaves is found to be sister to the rest of <i>Antherostele</i> species. <i>Antherostele</i> is hypothesized to originate from montane regions and diversified by forming larger leaves following dispersal to the shaded forest understory. From the five species of <i>Antherostele</i> currently recognized in the study, two are endangered (<i>A. banahaensis, A. grandistipula</i>) and three are critically endangered including a new species (<i>A. callophylla, A. luzoniensis, A.</i> sp. nov.) following the criteria of IUCN
Abstract— Little is known about the effects of habitat fragmentation on the patterns of genetic diversity and genetic connectivity of species in the remaining tropical forests of Southeast Asia. This is particularly evident in Cebu, a Philippine island that has a long
history of deforestation and has lost nearly all of its forest cover. To begin filling this gap, data from 13 microsatellite loci developed for Tetrastigma loheri (Vitaceae), a common vine species in Philippine forests, were used to study patterns of genetic diversity and genetic connectivity
for the four largest of the remaining forest areas in Cebu. Evidence of relatively high levels of inbreeding was found in all four areas, despite no evidence of low genetic diversity. The four areas are genetically differentiated, suggesting low genetic connectivity. The presence of inbreeding
and low genetic connectivity in a commonly encountered species such as T. loheri in Cebu suggests that the impact of habitat fragmentation is likely greater on rare plant species with more restricted distributions in Cebu. Conservation recommendations for the remaining forest areas
in Cebu include the establishment of steppingstone corridors between nearby areas to improve the movement of pollinators and seed dispersers among them.
Antherostele samarensis, a new species from Mt. Sohoton, Samar, Philippines, is here described and illustrated. This seemingly rare species is the second record of Antherostele in the locality. It is characterized by the non-canaliculate petioles, small triangular stipules, colleters distributed throughout the adaxial side of the stipules, small calyces, and strongly reflexed corolla lobes. The affinity among the new species and the other species of the genus is also discussed.
Premise: Rafflesia are rare holoparasitic plants. In the Philippines, all but one species are found only on single islands. This study aimed to better understand the factors contributing to this distribution pattern. Specifically, we sought to determine whether narrow environmental tolerances of host and/or parasite species might explain their island endemicity, or, instead or in addition, the limited distribution of Rafflesia species is the result of a narrow overlap between the environmental requirements of host and parasite. Methods: We used Maxent species distribution modeling to identify areas with suitable habitat for R. lagascae, R. lobata, and R. speciosa and their Tetrastigma host species. These analyses were carried out for current climate conditions as well as two future climate change scenarios. Key results: Whereas species distribution models indicated suitable environmental conditions for the Tetrastigma host species in many parts of the Philippines, considerably fewer areas have suitable conditions for the three Rafflesia species. Some of these areas are found on islands from which they have not been reported. All three species will face significant threats as a result of climate change. For R. lagascae and R. lobata, these may include a loss of suitable area as a result of changes to the distribution of their host species. Conclusions: Our results suggest that limited inter-island dispersal abilities and/or specific environmental requirements are likely responsible for the current pattern of island endemicity of the three Rafflesia species, rather than the environmental requirements of their Tetrastigma host species.
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