Evaluating the utility of protected area status and conservation legislation in tropical forest conservation using satellite data: a case study of the great hornbill in Thailand

Preserving wildlife and their environment from anthropogenic activities requires identification and establishment of protected areas, and monitoring of their long-term effects on wildlife and habitat. Tropical forests are one of the most at-risk habitats and many tropical species have become extinct recently due to human activity. It is imperative to monitor habitat in protected areas and without in order to identify strategies and legislative policies that optimize conservation outcomes. To this end, I quantified habitat fragmentation for the great hornbill (Buceros bicornis) in Om Koi Wildlife Sanctuary, Thailand, pre- and post-establishment, within and outside the protected area, from 1973, 1985, and 1992, to assess the effectiveness of the protected area status, established in 1978, and a national logging ban, established in 1989, in preserving and restoring hornbill habitat. The results demonstrate that the establishment of Om Koi Wildlife Sanctuary did not decrease the rate of hornbill habitat fragmentation relative to areas outside the protected area. While the protected area had less fragmentation to begin with, protection status did not affect the rate of loss. Fragmentation increased significantly both inside and outside the protected area between the first and second time points (p < 0.05), after the protected area was first established. However, the national logging ban policy implemented in 1985 seems to have successfully halted the fragmentation of habitat within the protected area and surrounding unprotected areas, with all areas showing no significant change (p > 0.05). While not significant, the rate of fragmentation outside the protected area was greater. This suggests that the establishment of a protected area alone may not be sufficient to stop or reverse anthropogenic damage to endangered habitat and the species that utilize these environments. The incorporation of multiple strategies for management is likely needed to increase the ability of protected areas to preserve tropical forest species and habitats. The assessment of protected areas via satellite and ground-level data is an essential tool for evaluating the effectiveness of conservation strategies and improving outcomes.

The debate about the effects of habitat fragmentation: causes and consequences

Con la creciente pérdida y fragmentación de los ecosistemas naturales, entender cómo responden las especies a estos cambios nunca ha sido más urgente. Hoy existe consenso acerca del fuerte impacto negativo de la pérdida de hábitat sobre la biodiversidad. Sin embargo, el efecto de la fragmentación del hábitat ha sido muy debatido. En esta revisión, proponemos un esquema que evalúa las causas y consecuencias del debate. Sugerimos que es causado por el uso de diferentes definiciones y conceptualizaciones de la fragmentación (causas distales), las cuales promueven el uso de distintas metodologías de estudio (causas proximales). Algunos estudios consideran la fragmentación como un proceso inseparable de la pérdida de hábitat y de otras amenazas locales (p.ej. efectos de borde y aislamiento), por lo que miden sus efectos a escala de sitio, de parche o de paisaje, sin controlar necesariamente el efecto de la pérdida de hábitat. Otros consideran la fragmentación como un patrón que describe la configuración del hábitat en el paisaje, y cuyo efecto puede y debe ser evaluado independientemente del efecto de la cantidad de hábitat (i.e. fragmentación per se) usando el paisaje como unidad de análisis. Como consecuencia, los primeros usualmente concluyen que la fragmentación tiene efectos fuertes y negativos sobre la biodiversidad, mientras que los segundos concluyen que dichos efectos son generalmente débiles, y positivos cuando son significativos. Entender las causas y consecuencias de este debate es crítico para aplicar medidas de conservación más adecuadas.

No Evidence of Low Genetic Diversity Despite High Levels of Inbreeding and Poor Genetic Connectivity Among Tetrastigma loheri (Vitaceae) Populations in Remaining Forest Areas in Cebu, Philippines

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.

Habitat Integrity in Protected Areas Threatened by LULC Changes and Fragmentation: A Case Study in Tehran Province, Iran

The integration and connection of habitats in protected areas (PAs) are essential for the survival of plant and animal species and attaining sustainable development. Investigating the integrity of PAs can be useful in developing connections among patches and decreasing the fragmentation of a habitat. The current study has analyzed spatial and temporal changes to habitat to quantify fragmentation and structural destruction in PAs in Tehran Province, Iran. To achieve this purpose, the trends in land use/land cover (LULC) changes and the quantitative metrics of the landscape ecology approach have been examined. The results revealed that in Lar National Park, low-density pasture has the top increasing trend with 4.2% from 1989 to 2019; in Jajrud PA, built-up has the top increasing trend with 1.5% during the studied years; and among the land uses in TangehVashi Natural Monument, bare land has the top increasing trend with 0.6% from 1989 to 2019. According to the findings, habitat fragmentation and patch numbers have expanded in the studied areas due to the development of economic and physical activities. The results also indicate that the current trend of habitat fragmentation in PAs will have the highest negative impacts, especially in decreasing habitat integrity, changing the structure of patterns and spatial elements, and increasing the edge effect of patches.

DNA metabarcoding unveils the effects of habitat fragmentation on pollinator diversity, plant-pollinator interactions, and pollination efficiency in tropical islands

Habitat fragmentation is known to affect biodiversity, but the impact on pollinators and their interactions with plants is still unclear in anthropized landscapes. Islands are open-air laboratories for ecological studies with simplified communities and interactions, suitable to disentangle how land-use alteration impacts pollination ecology and its ecosystem service. Here, we used Maldives islands as model systems to investigate how pollinator richness, their mutualistic interactions with plants, and pollination efficiency are shaped by the degree of green area fragmentation (i.e., gardens, parks and semi-natural green covered patches), by considering both community- and species-level responses. To do this, we surveyed pollinators from 11 islands showing a gradient of green area fragmentation. In order to characterize the interactions between plants and pollinators and obtain a novel and comprehensive view of the key ecological dynamics, a DNA metabarcoding approach was adopted to identify the pollen carried by pollinators. We found that green area fragmentation at intermediate levels played positive effects on pollinator richness. However, fragmentation decreased interaction network complexity. Intriguingly, body size mediated the effect of landscape alteration on plant-pollinator interactions, as only the largest bee species expanded the foraging breath in terms of transported pollen richness at increasing fragmentation. In parallel, the pollination efficiency increased with pollinator species richness in two sentinel plants. This study shows that moderate landscape fragmentation of green areas shapes the ecosystem service of pollination, where in spite of interactions being less complex and mediated by pollinator body size, pollinator biodiversity and potential plant reproduction are supported.

Movement and dispersal of a habitat specialist in human-dominated landscapes: a case study of the red panda

Background Habitat specialists living in human-dominated landscapes are likely to be affected by habitat fragmentation and human disturbances more than generalists. But there is a paucity of information on their response to such factors. We examined the effect of these factors on movement patterns of red pandas Ailurus fulgens, a habitat and diet specialist that inhabits the eastern Himalaya. Methods We equipped 10 red pandas (six females, four males) with GPS collars and monitored them from September 2019 to March 2020 in Ilam, eastern Nepal. We collected habitat and disturbance data over four seasons. We considered geophysical covariates, anthropogenic factors and habitat fragmentation metrics, and employed linear -mixed models and logistic regression to evaluate the effect of those variables on movement patterns. Results The median daily distance travelled by red pandas was 756 m. Males travelled nearly 1.5 times further than females (605 m). Males and sub-adults travelled more in the mating season while females showed no seasonal variation for their daily distance coverage. Red pandas were relatively more active during dawn and morning than the rest of the day, and they exhibited seasonal variation in distance coverage on the diel cycle. Both males and females appeared to be more active in the cub-rearing season, yet males were more active in the dawn in the birthing season. Two sub-adult females dispersed an average of 21 km starting their dispersal with the onset of the new moon following the winter solstice. The single subadult male did not disperse. Red pandas avoided roads, small-habitat patches and large unsuitable areas between habitat patches. Where connected habitat with high forest cover was scarce the animals moved more directly than when habitat was abundant. Conclusions Our study indicates that this habitat specialist is vulnerable to human disturbances and habitat fragmentation. Habitat restoration through improving functional connectivity may be necessary to secure the long-term conservation of specialist species in a human-dominated landscape. Regulation of human activities should go in parallel to minimize disturbances during biologically crucial life phases. We recommend habitat zonation to limit human activities and avoid disturbances, especially livestock herding and road construction in core areas.

The effects of habitat fragmentation on the genetic structure of wild boar (Sus scrofa) population in Lithuania

Background Wild boar (Sus scrofa) is a widely distributed ungulate whose success can be attributed to a variety of ecological features. The genetic variation and population structure of Lithuania’s wild boar population have not yet been thoroughly studied. The purposes of this study were to investigate the genetic diversity of S. scrofa and assess the effects of habitat fragmentation on the population structure of wild boar in Lithuania. A total of 96 S. scrofa individuals collected from different regions of Lithuania were genotyped using fifteen microsatellite loci. Results The microsatellite analysis of the wild boars indicated high levels of genetic diversity within the population. Microsatellite markers showed evidence of a single panmictic wild boar population in Lithuania according to STRUCTURE’s highest average likelihood, which was K = 1. This was supported by pairwise Fst values and AMOVA, which indicated no differentiation between the four sampling areas. The results of the Mantel test revealed a weak isolation by distance and geographic diversity gradients that persisted between locations. Motorway fencing and heavy traffic were not an effective barrier to wild boar movement. Conclusions There was limited evidence of population genetic structure among the wild boar, supporting the presence of a single population across the study area and indicating that there may be no barriers hindering wild boar dispersal across the landscape. The widespread wild boar population in Lithuania, the high level of genetic variation observed within subpopulations, and the low level of variation identified between subpopulations suggest migration and gene flow between locations. The results of this study should provide valuable information in future for understanding and comparing the detailed structure of wild boar population in Lithuania following the outbreak of African swine fever.