Comparison of species diversity of mammals and herpetofauna between burnt and unburnt land after one year of fire in RAJ Oil Palm Estate, South Sumatera

Frequent fires are common in Indonesia, particularly within oil palm plantations, and are believed to negatively affect the diversity of native plants and animals. In 2018, the RAJ oil palm plantation in South Sumatra experienced a fire incident. This study aimed to assess the contrasting diversity of mammal and herpetofauna species and the impact of fire on species abundance over one year. Data were collected in burnt and unburnt areas with two land cover types, grass and gelam. Transect strips, 1 km long and 50 m wide, were established in each land cover for mammal observations, while the Visual Encounter Survey (VES) method was used for herpetofauna. Data were collected during active animal hours: 06:00-08:00 and 16:00-18:00 for mammals, and 19:00-21:00 for herpetofauna, with three observation rounds each. The analysis included number of eah species, species richness and evenness indices, community similarity index, and percentage of species loss and gain. Results revealed 5 mammal and 5 herpetofauna species in both land cover types. Species Diversity (H′) and Richness (Dmg) Indices differed for each animal group. Generally, H′ and Dmg were higher in burnt areas for mammals, while for herpetofauna, values were greater in unburnt land. Mammal species loss was lower than in burnt areas, with 20% loss and 60% gain in grassland, and 33% loss and gain in gelam land. Herpetofauna loss and gain percentages were similar in unburnt and burnt lands, at 20% for grassland and 33% for gelam land.


Introduction
Generally, the existence of wild animal species in their natural habitat, in a forest area or plantation area, naturally always dynamic experience in accordance to exchange of their habitat dynamic.Sometimes the number of animal species and the condition of their population will increase in accordance with the increase of habitat quality and carrying capacity and the controlling of other disturbance factors like predators.
On the other hand, the number of animal species and the condition of the population in a habitat sometimes also decrease because there are disturbance factors that impact damage to the habitat quality and carrying capacities.One of the causal factors to damage the habitat quality is land fire.Fires often occur in Indonesia, not only in forest areas but also on plantation land, including oil palm plantations.In general, the factors that cause forest and land fires are natural and human factors that are carried out intentionally or unintentionally.These forest and land fires could potentially result in adverse effects on environmental quality, both directly and indirectly, and are strongly believed to exert influence on the biodiversity of indigenous flora and fauna at the fire site and in the aftermath of the fire incident.It has been indicated by [1] that forest and land fires yield unfavorable consequences such as alterations in climate patterns, disruption of public well-being, economic detriments to the nation, and the obliteration of natural habitats for wildlife.Moreover, [2] contends that these fires have the potential to lead to immediate fatalities among wildlife.An instance of such fire occurrence in 2018 transpired within the confines of the RAJ oil palm plantation situated in South Sumatra.This incident encompassed a burned area estimated at 110 hectares or, as per assessments made by the Ministry of Environment and Forestry, potentially expanding to 500 hectares.
Forest and land fires, especially in areas with the land status that are encumbered with management rights such as oil palm plantations, then the fire incident in the perspective of environmental law can be confronted as an illegal act because there is a deliberate factor that causes the fire, with demands compensation for all environmental impacts caused by the fire, such as the potential loss of animal species diversity, population changes, and the potential for extinction of flora and fauna diversity.In cases related to fires on RAJ oil palm plantation land in South Sumatra, claims for compensation due to fire are determined by making assumptions about the potential loss of species, changes in population, and extinction of flora and fauna diversity to a maximum of 100%.The important question is, is it true that scientifically from an ecological perspective, every event of a plantation or forest fire will negatively impact the potential loss of species diversity, population changes, and extinction of flora and fauna species to the maximum (100%) as the lawsuits mentioned above?Or is the actual negative impact on the environment not always the maximum (100%)?To answer this question, a comprehensive scientific study is needed from an ecological perspective, particularly in relation to the potential loss, survival, and gain of fauna species in these habitats after a fire, especially for mammals and herpetofauna species diversity In accordance with ecological theory, particularly the theory of wildlife adaptation and habituation, each wild animal species is expected to adjust its behavior to ensure survival when confronted with shifts in environmental conditions.Generally, following the ecological theory, when a fire occurs within an ecosystem or habitat, the initial response of most wild animal species is to relocate to alternative habitats to evade the fires.However, species with limited mobility may face threats of mortality or manage to endure within the habitat.Naturally, an ecological rejuvenation process follows a fire in an ecosystem or habitat, characterized by the emergence of new plant species.Over time, wild animals gradually readapt to these altered conditions, reoccupying the previously burned areas as their habitats.In such contexts, the potential arises for novel wildlife species (gains) to establish the former fire zone as their habitat.
In light of the aforementioned natural phenomena and ecological circumstances, it can be posited that fires, beyond their negative impact on potential wildlife species diversity loss, also harbor the potential for species that can thrive within these habitats.These species might even result in a gain of new wildlife types that adopt the former fire-affected region as their habitat.Case in point, [3] illustrates that insects like butterflies can adapt in response to changing environments post-fire.[4] similarly indicates that butterflies, possessing robust flight capabilities and expansive wings, can promptly respond to post-fire vegetation alterations.[5], through a study of birds and butterflies within the RAJ oil palm plantation one year after a fire, demonstrates the capacity of birds and butterflies to survive within the burnt area and even experience positive gains by incorporating new species, alongside the existing ones.Given this discourse on butterflies and birds, a pertinent question arises: what is the impact of fires on the diversity of mammal and herpetofauna species?[6] and [7] note the heightened susceptibility of herpetofauna to environmental changes, as their entire life dynamics hinge on the climatic conditions of their habitat.
Based on the proposed ecological phenomenon, akin to the example of butterflies and birds, it becomes imperative to carry out a thorough investigation in order to gauge the magnitude of shifts in potential species diversityencompassing loss, gain, or alterationwithin the realms of mammals and herpetofauna consequent to a fire event and its aftermath.The outcomes of this comprehensive inquiry can serve as a pragmatic and equitable foundation, supplying heightened scientific credibility.Such findings can be employed as a more objective benchmark for legal deliberations, particularly in instances where companies operating within a concession area have encountered fire incidents, akin to the circumstances observed at the RAJ oil palm plantations.From an ecological perspective, the results of this study have significance and strong relevance for demonstrating the existence of an oil palm plantation area as an ecosystem with the function of preserving flora and fauna biodiversity as one of its legal mandates.From an economic perspective, an oil palm plantation area with high animal biodiversity will also have high economic value.The presence of certain species of mammals and herpetofauna in an ecosystem can play an important role in the food chain, such as pest control and diseases so that it can have a positive economic impact on the oil palm plantation company.
Building upon the preceding elucidation, this study was undertaken with the primary objective of ascertaining and dissecting the disparities in diversity and composition of mammal and herpetofauna species.Additionally, it aimed to investigate the dynamics of species loss and gain within the context of the burnt and unburnt zones, one year following the fire event within the confines of the RAJ oil palm plantation.

Research method
The data collection process took place at the RAJ oil palm plantation, situated within the precincts of Kayu Agung District, Ogan Komering Ilir Regency, South Sumatra.This data collection spanned a duration of 10 days, spanning from August 29 to September 9, 2019.The data collection endeavors were conducted one year subsequent to the fire incident, encompassing two distinct land cover categories: post-burn areas and unburnt areas.Each category was further segmented into pairs of grass and gelam land cover types.The foundational premise underlying this research is grounded in the assumption that conditions within unburnt regions mirror those present in post-burnt areas prior to the ignition of fires.
Observations and data collection pertaining to mammal and herpetofauna species were meticulously conducted within each distinct land cover type.This process involved delineating an observation strip in the form of a transect strip, as illustrated in Figure 1, for the purpose of mammalian inventory.The dimensions of this lane encompassed a length of 1 kilometer and a width of 100 meters.Simultaneously, for herpetofauna inventory, the Visual Encounter Survey (VES) technique [8] was adopted, as depicted in Figure 2.These data collection endeavors were executed during the active hours of animals, specifically from 06:00 to 08:00 and 16:00 to 18:00 for mammals, while the corresponding timings for herpetofauna were from 19:00 to 21:00.Each session consisted of three observations.In order to accurately distinguish and categorize animal species, a variety of methods were employed.For instance, small mammals were captured utilizing traps, while square cardboard boxes were utilized for the capture of herpetofauna specimens.To help introduce species of animals directly in the field, a guidebook for mammals was used, as well as a field guide for herpetofauna.For the purpose of further identification of several species of animals, especially for herpetofauna, preservation with alcohol and storage of specimens in plastic bags was undertaken.Obtained data include general land cover conditions for each type of habitat, burned and unburned land, in pairs for each type of grass cover and gelam cover.In addition, the main data collected in the research are species diversity of mammals and herpetofauna, including the number of species, number of individuals, richness, and evenness of species, as well as the composition of species of animals on burnt and unburnt land one-year post-fire.The collected data was then analyzed to determine the comparison of the number of species, Diversity Index (H), Margalev Species Index (Dmg), Evenness Evenness Index (E) [9] and Sorensen Community Similarity Index (IS) [10], percentage of species loss and gain.

Mammalia
Overall, the observations of mammal species in both pairs of unburnt and burnt land with grass and gelam covers indicate that there were five species of mammals found with a total of 28 individuals.The five species of mammals found were: long-tailed monkeys (Macaca fascicularis), wild boars (Sus scrofa), otters (Aonyx cinerea), flat-headed cats (Prionailurus planiceps), and leopard cats (Prionailurus bengalensis).These five mammals are protected according to the IUCN Red List with threatened status.The results of the analysis showed differences in the number of species and the number of individuals of each species of mammals found in burnt and unburnt land, both for the land cover of grass or gelam.The highest number of species of mammals found in burnt grassland (PTR) was 4 species with fewer individuals (9 individuals) compared to the number of species found in unburnt grassland (TTR), which was 2 types but with a greater number of individuals (13 individuals).On the other hand, in the burnt land (PTG) and unburnt land (TTG), the number of species was found to be the same (2 types), but more individuals were found in the burnt gelam land (PTG) (4 individuals) compared to in the unburnt gelam land (TTG) (2 individuals) (Table 1).
This scenario further demonstrates that each mammal species exhibits distinct reactions to alterations in habitat conditions following a fire event.Certain mammal species display a favorable response by embracing the post-fire area as their habitat, while others exhibit a negative reaction by avoiding it.This response hinges on the potential presence of conducive factors, encompassing both biotic elements like the accessibility of nourishment and shelter, and abiotic elements such as temperature and humidity suitability.This realization also underscores the fire's capacity to trigger intricate transformations within the vegetation dynamics of the diverse post-burn ecosystem, potentially influencing the availability of sustenance for specific mammal species.The results also showed that one year after the fire it turned out that the burnt grassland (PTR) generally showed higher values of species diversity, species evenness, and species richness compared to that of unburned grassland (TTR).On the contrary, the unburnt gelam land (TTG) showed higher values of species diversity, species evenness, and species richness compared to the burnt gelam land (PTG).This phenomenon shows that ecologically fires of land that become wildlife habitats do not necessarily eliminate wildlife species as a whole, but there are wild species that can survive even if there are new species that occupy the habitat after the fire with different levels of diversity, evenness, and richness of mammal species.The results of the Community Similarity analysis of mammal species on burnt and unburnt land after one year of fire showed a different index value (Table 2).The highest value of the Community Similarity Index was found in unburnt grassland (TTR), unburnt gelam land (TTG), and burnt gelam land (PTG) of 0.33.A smaller index value of 0.2 was found between burnt grassland (PTR), unburnt gelam land (TTG), and burnt gelam land (PTG).

Herpetofauna
The outcomes stemming from the observation and classification of herpetofauna species within both unburnt and burnt terrains unveiled a collective tally of 5 distinct species, comprising a cumulative count of 23 individual organisms along the observation path.Notably, all five herpetofauna species fall under the protected classification of the IUCN Red List, designated as Least Concern (LC).Disparities surfaced in the abundance of both species and individual counts among herpetofauna species observed across burnt and unburnt terrains (refer to Table 3).
The count of herpetofauna species encountered one year post-fire was uniform between unburnt and burnt expanses, encompassing grass and gelam land cover types.Specifically, grasslands saw the discovery of 4 species, while gelam lands had 2 species.This configuration extended to burnt grassland (PTR) and unburnt grassland (TTR), each harboring 4 species.Notably, the total herpetofauna individual count in burnt grassland (PTR) surpassed that of unburnt grassland (TTR), tallying 10 individuals compared to 8. Likewise, unburnt gelam land (TTG) yielded 2 species and 3 individuals, while burnt gelam land (PTG) produced 2 species and 2 individuals.
The results of the data analysis showed that the species diversity index (H) and the evenness index (E) were found to be greater in burnt land compared to unburnt land, both in grass and gelam land.As for the index of species richness, the unburnt grassland (TTR) showed greater value than burnt grass 1243 (2023) 012023 IOP Publishing doi:10.1088/1755-1315/1243/1/0120236 land (PTR).On the contrary, the value of the species richness index in the burnt gelam land (PTG) was greater in unburnt gelam land (TTG).The results of the herpetofauna community similarity index showed that the highest value was found in unburnt grass land (TTR) and burnt grass land (PTR) which was equal to 0.6 whereas the lowest value was found in unburnt gelam land (TTG) and burnt gelam land (PTG) which is 0.33 (Table 4).

Losses and gains of species in land after one year old of fire
The results showed that fire incidents within the RAJ oil palm plantations yield repercussions extending beyond the loss of specific wildlife species.They encompass both the introduction of new animal species following the fire and the persistence of surviving species within the burnt and unburnt regions, across both grassland and gelam land covers.Generally, the study's outcomes indicated that one year subsequent to the fire within the RAJ oil palm plantations, the count of species that managed to endure reached 6 (constituting 37.50% of the total), while the count of species newly acquired (gained) also totaled 6 (37.50%).This gain surpassed the count of species lost, which stood at 4 (25.00%), as depicted in Table 5..
According to the data were shown that the number of species losses of mammalian and herpetofauna as the effect of land fire was relatively the same, as well as in grassland and gelam land.Meanwhile, the number of species gained was mostly mammalian species (4 species) compare to herpetofauna species (2 species).This condition can be interpreted that the mammalian species' most adaptive ability to use the habitat post-fire, especially in grassland compared to the herpetofauna species.But the adaptive ability to use the gelam land was relatively the same between mammalian and herpetofauna species.For the types of mammals that are able to survive due to fire are Prionailurus bengalensis in grassland and Macaca fascicularis in gelam land, while the lost species are Macaca fascicularis in the grassland and Sus scrofa gelam land.The species gain of mammals consists of Sus scrofa, Aonyx cinerea, and Prionailurus planiceps in the grassland and Aonyx cinerea in gelam land.In general, the percentage of species of mammals lost is only about 1 species (20%), but the percentage of species gain reached 60% (3 species) in grassland, while in gelam land, the percentage of specie lost and obtained (gain) are relatively the same (33%).
The findings from this study further underscore that mammalian and herpetofauna species exhibit distinct responses and adaptability levels towards the habitat conditions arising one year after a land fire event.Considering the delineated circumstances, it becomes evident that fires occurring within oil palm plantations, such as those observed at the RAJ oil palm plantation, don't invariably yield solely detrimental impacts leading to a decline in the diversity of wildlife species, particularly among mammals and herpetofauna.Instead, they may also elicit positive outcomes following a fire incident, manifested by the acquisition of novel and wild species that subsequently establish the land as their habitat.Between the two categories of burnt land, namely grass and gelam, notable variations arise in terms of the wildlife species that manage to persist, vanish, or emerge post-fire.This signifies that natural land fires catalyze an ecological recovery process.This is evidenced by the proliferation of new vegetation types and/or the proliferation of other animal species, which hold potential as sustenance sources for additional wildlife.This phenomenon is exemplified by their subsequent occupation of the fire-affected land as their habitat, serving purposes like foraging (feeding sites), refuge (cover), or even breeding locales.Similar observations are discernible among bird and butterfly species, as highlighted in [5].Within the ecological context, the availability of nourishment components within a habitat emerges as a pivotal aspect, often acting as both a significant habitat constituent and a constraining factor.This aspect is coupled with the availability of water and the appropriateness of temperature and humidity conditions.Regular monitoring must be done to ensure the dynamic of adaptation ability and survival of the species of mammals and herpetofauna in using the area after one-year-old of fire.
Through an ecological evolutionary lens, fire incidents engender a series of indirect repercussions, including the progression of succession [11].This phenomenon signifies the orchestrated shift in vegetation composition and environmental elements toward the ultimate climax community, stimulated by disturbances like fire [12].In the context of post-fire landscapes evolving as ecosystems undergoing successive transformations, their biophysical attributes undergo development.Consequently, such ecosystems possess the potential to serve as viable habitats for diverse mammals and herpetofauna species.Within this context, the prospect of acquiring novel species (gains) emerges, alongside the plausible scenario of former inhabitants returning to the fire-affected land, utilizing it once more as their habitat.
If the conditions of loss, gain, and survival of the diversity of mammalian and herpetofauna species above are seen as part of the wealth of an ecosystem in general and specifically in the oil palm plantation area which ecologically and economically have certain beneficial values, then an ecosystem with a wealth of high biodiversity normatively can be ascertained to have an important ecological role in maintaining and creating a balance and sustainability of the ecosystem functioning.Similarly, economically, an ecosystem with high biodiversity, including the presence of mammals and herpetofauna species, has ahigh economic value.Therefore, the important thing that still needs to be studied further is how the ecological role and economic benefit value of the diversity of mammal species and herpetofauna in the ecosystem of oil palm plantations.The existence of several species of mammals such as Macaca fascicularis and Sus scrofa in a plantation ecosystem is often seen as having a negative impact ecologically and economically, including in oil palm plantation areas, but so far there has been no specific study regarding the benefits or losses of the ecology and economy.Therefore, in the future comprehensive study is needed regarding the existence of certain wild species on the economic and ecological value of an oil palm plantation ecosystem, as well as an estimate of the amount of economic value in the event of a loss or gain of the species diversity of mammals and herpetofauna in the oil plantation ecosystem.

Conclusion
Land fires, contrary to common perception, do not consistently lead to adverse outcomes solely through the loss of overall wildlife species diversity.They can also yield positive consequences, marked by the emergence of new wildlife species alongside the survival of existing species in the burnt areas one-year post-fire.
A comparative examination of the cumulative species count within the two observation paths for each land cover type (grass and gelam) reveals an equivalence of 5 mammal species and 5 herpetofauna species for both unburnt and burnt areas.Distinct dissimilarities manifest in the Species Diversity Index (H'), Evenness Index (E), Species Richness Index (Dmg), and the Community Similarity Index (IS), reflecting variations among animal groups and between burnt and unburnt zones.Specifically, the values of H', E, Dmg, and IS for mammal species are notably amplified within the burnt areas one-year post-fire compared to the unburnt regions.In contrast, index values for herpetofauna species exhibit greater prominence in unburnt territories as opposed to the burnt areas..The percentage of species loss due to land fires for mammals is smaller than the percentage gain in burnt areas compared to unburnt areas.In grassland cover, there is a 20% loss of species versus a 60% gain of species, and in gelam land cover, there is a 33% loss of species compared toa 33% of species gain.For herpetofauna species diversity, the percentage of loss and gain of species is relatively the same both in unburnt land and burnt land, which is 20% for grassland and33% for gelam land.
Among the species of mammals and herpetofauna that are found to survive, lose, and gain in an ecosystem, such as Macaca fascicularis and Sus scrofa for mammals, and Fejerforya sp., Hylarana erythroaea, Xenopeltis unicolor, and Eutropis multifasciata for herpetofauna, they can play a role and have both positive and negative impacts.Therefore, it is necessary to study how much the potential benefits and ecological and economic losses from the presence of these species in the oil palm plantation ecosystem.

Table 1 .
Mammal species found in burnt and unburnt grass and gelam land at RAJ Oil Palm Plantation in South Sumatra

Table 2 .
Community Similarity Index of mammal species in burnt and unburnt land covered in grass and gelam at the RAJ Oil Palm Plantation South Sumatra

Table 3 .
Herfetofauna species found in burnt and unburnt land covered in grass and gelam at RAJOil Palm Plantation in South Sumatra

Table 4 .
Community Similarity Index of herpetofauna species in burnt and unburnt land covered in grass and gelam at the RAJ Oil Palm Plantation South Sumatra

Table 5 .
The number of species that survived, lost, and gained after the fire for grass and gelam land in RAJ Oil Palm Plantations South Sumatra