**Abstract**

Bats are among the most misperceived and undervalued animals on the planet. For wildlife ecologists, they are wonderful and incredibly fascinating creatures, but people's feelings about bats are often negative, perhaps because bats are so mysterious. Unfortunately, these fears and myths about bats threaten conservation, biodiversity, and the entire ecosystem. Bats are among the most diverse and geographically dispersed group of living mammals. They contribute to several ecosystem services and act as biological pest crop control agents. Their abundance may reflect changes in populations of arthropod prey species. Also, bats have significant potentials as bioindicators that demonstrate measurable responses to climate change and habitat loss and that induce large-scale impacts on the biota. Indeed, bat conservation is fundamental not only for biodiversity, but also because these flying mammals provide essential ecological and economic services to humans.

**Keywords:** agricultural pests, ecosystem services, bioindicators, environmental stressors

## **1. Introduction**

Many ecosystems worldwide have become more threatened than ever before through many anthropogenic activities such as urbanization, deforestation and different kinds of pollution. Healthy ecosystems are crucial for human wellbeing improvement, since they provide various ecological services (e.g., insect suppression, pollination, seed dispersal, water and air purification, stabilization of soils, decomposition of wastes, binding of toxic substances, mitigation of diseases, mitigation of floods, and regulation of climate, etc.), many provisions (e.g., food, fuel, fiber, and medicines), and cultural benefits (e.g., esthetic, spiritual, educational, and recreational) [1]. These processes and products are commonly referred to as ecosystem services [2, 3] and have been duly recognized by the United Nations Millennium Ecosystem Assessment [4, 5].

Furthermore, ecosystem services mainly depend on the type of ecosystem as well as the organisms that they constitute. In this chapter, the ecosystem services provided by bats are considered. Bats have been on Earth for over 52 million years [6], with over 1400 species worldwide. They are classified as the second-largest mammalian order with great physiological and ecological diversity [7]. Due to their diverse behavioral, roosting, and feeding habits, many species of bats roost during the daytime in foliage, caves, rock crevices, hollows of trees, beneath exfoliating bark, and different manmade structures [8–11]. While during the night, bats fill the sky to forage on a variety of food items ranging from insects, nectar, and fruit, to seeds, frogs, fish, small mammals, and even blood.

## **2. Bat: human interaction**

Bat-human interrelationships are probably as old as humanity itself. However, the oldest bat fossils are estimated to date back to the Eocene, exceeding 50 million years ago [6]. These nocturnal, fast-flying, and secretive mammals may have been as enigmatic to human ancestors as they are to most of us today. The ancient coexistence of people and bats has been translated into enormous historical and contemporary cultural representations of bats in local folklore [12–14]. This ancient connection exquisitely celebrated in abundant reddish-terracotta rock paintings of bats was made by hunter-gatherer colonizers of the northwest Amazon during the Late Pleistocene/Early Holocene transition [15]. Human still considers bats to be loathsome and fearful creatures, despite the countless research investigating the contributions of bats to the ecosystem and the benefits they provide to human wellbeing [16–21].

#### **2.1 Bat's negative stigma**

Contrary to popular belief, bats do not attack people; they do not get tangled in people's hair; and even vampire bats are not real vampires (vampire bats lick blood but do not suck blood). Underlying these negative sentiments are relatively pervasive associations between bats and death [22, 23], witchcraft [24–26], vampires [27–29], malevolent spirits [30–32], and evil [33, 34].

Across much of Europe, disdain and fear of bats are largely embroiled in Church doctrine, where bats are often used to symbolize Satan [35]. However, elsewhere (particularly throughout Southeast Asia, China, and Japan), bats are also associated with luck and good fortune [13, 36] and used as spiritual totems [37, 38]. Among several indigenous groups in Mexico, bats have been considered messengers from the underworld and important symbols of fertility [39].

Furthermore, as human numbers increase and people encroach deeper into the remaining natural habitats, human-bat interactions are becoming more frequent, often with undesirable consequences for both humans and bats.

Human-bat conflicts often arise from damage to buildings or as a result of noise/ smelly caused by synanthropic species [14, 40] or due to fruit crop invasion by frugivorous species [21, 41]. These are other key areas in which ethnobiological work can substantially contribute to support evidence-based and culturally sensitive strategies aimed at reducing negative feelings toward bats.

#### **2.2 Ecosystem services**

An ecosystem is a system consisting of biotic and abiotic components that function together as a unit. The biotic components include all the living things whereas the abiotic components are the non-living things. Thus, an ecosystem science definition entails an ecological community consisting of different populations of organisms that live together in a habitat. Ecology, which is the scientific study of the interactions between populations or between organisms and the environment, can be viewed at the level of an individual, population, community, or ecosystem. Ecology at the level of individuals is mainly concerned with the physiology, reproduction, and development of an organism. At the level of population, ecology deals primarily with the attributes and the various factors affecting the population. At the level of community, ecology investigates the interactions between populations and community patterns. At the ecosystem level, ecology brings them all together to understand how the system functions as a unit [42].

#### *Bats and Ecosystem Management DOI: http://dx.doi.org/10.5772/intechopen.101600*

Ecosystem services are the benefits obtained from the environment that increase human well-being. Economic valuation is conducted by measuring the human welfare gains or losses resulting from changes in the provision of ecosystem services. Bats, which live on all continents except Antarctica, are essential members of many types of ecosystems, ranging from rainforests to deserts. By fulfilling their ecosystem roles, bats promote biodiversity and support the health of their ecosystems. Due to the rich diversity of dietary habits of bats, ranging from species that feed on insects and other arthropods to those that feed on fruit, nectar, and flowers, they have long been postulated to play important roles in ecological and economic services. Moreover, other species that feed on seeds, frogs, fish, small mammals, and even blood also play important roles in ecosystems as predators or prey in ecosystems sustainability. Modifying ecosystems to facilitate socioeconomic development is necessary but how can we avoid damaging important ecosystem services? As a prerequisite, we need to understand how ecosystem services contribute to people's livelihoods and well-being.

### *2.2.1 Ecological services*

Bats have long been known as the main contributor to remarkable ecosystem benefits, are significant suppressors of agricultural pests [43–46], consume important disease vectors, such as malaria-bearing mosquitos [47], with an important role in seed dispersal, pollination, material and nutrient distribution, and recycle [48].

One of the most troubling problems of the farming industry is insect pests, which affect crop production worldwide. Inhibitors of natural insect pests such as bats, as major predators of arthropods, provide valuable ecosystem benefits for crops cultivation [48, 49]. Indeed, herbivorous arthropods destroy approximately 25–50% of crops worldwide [50, 51], in response to these threats, it is clear that the application of synthetic pesticides has increased which in turn has led to several unintended consequences including human health risks, degradation of ecosystem function, evolved toxicity resistance by pests, and severe alterations in the agribusiness dynamics [50, 52, 53].

Indeed, the elimination of beneficial vertebrate predators that act as biocontrol of insects, such as bats, insect species that are not normally considered pests are often elevated to pest status [53, 54]. Thus, the promotion of biological controls can reduce the widespread and indiscriminate use of chemical pesticides [55]. About 99% of potential crop pests are limited by natural ecosystems [53, 56] of which some fraction can be attributed to predation by bats [57]. For example, a colony of 150 big brown bats (*Eptesicus fuscus*) in the midwestern United States annually consume approximately 600,000 spotted cucumber beetles (*Diabrotica undecimpunctata*), 194,000 June beetles (Scarabidae), 158,000 leafhoppers (Cicadellidae), and 335,000 stinkbugs (Pentatomidae), which are severe crop pests [58]. A Brazilian free-tailed bat (*Tadarida brasiliensis*) can eat up to 20 females of corn earworm moth (*Helicoverpa zea*), one of the costliest agricultural pest insects in one night [59]. In fact, each moth can potentially produce 10,000 crop-damaging caterpillars each night [60]. Bats are just one of several groups of animals that naturally prey on mosquitoes. A Florida colony of 30,000 southeastern myotis (*Myotis austroriparius*) eats 50 tons of insects annually, including more than 15 tons of mosquitoes (**Figure 1**) [61, 62].

Therefore, insectivorous bat species, which largely feed on airborne insects and other arthropods, considerably contribute to the suppression of insects that harm the agricultural industry or transmit specific pathogens to humans, consequently contributing to the maintenance of ecosystem stability.

#### **Figure 1.**

*Insectivorous bat species (a) big brown bats (Eptesicus fuscus); (b) Southeastern myotis (Myotis austroriparius); (c) Brazilian free-tailed bat (Tadarida brasiliensis): photos by Merlin Tuttle's Bat Conservation/MerlinTuttle.org.*

#### **Figure 2.**

*A lesser long-nosed bat (Leptonycteris yerbabuenae) feeding on a cross-sectioned saguaro cactus flower: photo by Merlin Tuttle's Bat Conservation/MerlinTuttle.org.*

Another important ecosystem service provided by bats is pollination. Although, bat pollination is relatively uncommon when compared with bird or insect pollination, it involves an impressive number of economically and ecologically important plants [63]. Plant-visiting bats play a remarkable role in facilitating reproductive success and the recruitment of new seedlings [48]. For instance, bat-pollinated columnar cacti (Cactaceae) and agaves (Asparagaceae) are among the most important species as dominant vegetation elements in arid and semiarid habitats (**Figure 2**) [48].

Furthermore, seed dispersal is a major way in which animals contribute to ecosystem succession by depositing seeds from one area to another [64]. Frugivorous bats play a tremendous role in dispersing the seeds of tropical trees and shrubs to produce fleshy fruits as 50–90% of these trees are adapted to the consumption of vertebrates [65]. Generally, frugivorous bats help maintain the diversity of forests by dispersing seeds across different ecosystems, often introducing novel plant species into previously disturbed landscapes [64].

In contrast to predation, which is an antagonistic population interaction, pollination, and seed dispersal are mutualistic population interactions in which plants provide a nutritional reward (nectar, pollen, and fruit pulp) for a beneficial service [48]. Indeed, frugivorous bats as well as nectarivorous bats provide valuable ecosystem services by pollinating plants, dispersing pollen, and thus helping to maintain the genetic diversity of flowering plants.

Bats offer an important multisensory role in assessing ecosystem health either by directly contributing to regulating services to agricultural production or indirectly

#### *Bats and Ecosystem Management DOI: http://dx.doi.org/10.5772/intechopen.101600*

by providing forage and nesting habitat for pollinators and seed dispersers. To some extent, bat guano has great ecological potential for soil fertility and nutrient distribution, as bats sprinkle them over the landscape overnight, they facilitate nutrient redistribution within ecosystems [66]. In other words, bat guano supports a great diversity of organisms including arthropods, fungi, bacteria, and lichens representing different trophic levels by supporting their ecosystems [67].

Moreover, bats have enormous potential as bioindicators of both disturbance and the existence of contaminants [68]. They show taxonomic stability, trends in their populations can be monitored, short- and long-term effects on populations can be measured and widely distributed worldwide [68–70]. Since insectivorous bats occupy high trophic levels, they are sensitive to the accumulations of pesticides and other toxins, and changes in their abundance may reflect changes in populations of arthropod prey species [71]. In particular, changes in bat numbers or activity can be related to climate change, deterioration of water quality, agricultural intensification, loss and fragmentation of habitats, fatalities at wind turbines, disease, pesticide use, and overhunting [68], and hence bat populations are affected by a wide range of stressors that affect many other taxa. Overall, there is an urgent need to implement a global effort for monitoring bat populations, to ensure that their role as bioindicators can be used to their full potential.

## *2.2.2 Economic services*

Estimating the economic importance of bats in agricultural systems is challenging; however, the bats value in pest suppression illustrates an important agricultural service by increasing the monetary gain of farmers, and consequently supporting food security [49]. They consume enormous quantities of insect pests that cost farmers and foresters billions of dollars annually [59]. In USA, due to the fact of insect pests are eliminated by bat predation, the estimated value of bats as a result of reduced costs of pesticide applications is in the range of \$3.7–\$53 billion per year [66]. These estimates include the reduced costs of unnecessary pesticide applications to suppress insects consumed by bats [72].

Bats provide substantial ecosystem services worldwide, and their benefits to human economies are not limited to agricultural pest control. For example, pioneering research in tropical ecosystems shows the importance of plant-visiting bats in the pollination of valuable fruit crops [73, 74]. There are 289 Old World tropical plant species, which rely on pollination and seed dispersal services by bats for their propagation, providing human with about 448 products in a variety of categories, for instance, wood products (23%); food, drinks and fresh fruit (19%); medicine (15%); dye, fiber, animal fodder, fuel wood, and others (43%) [57]. In addition to some cash crops such as wild bananas (*Musa acuminata*), mangos (*Mangifera indica*), breadfruits (*Artocarpus altilis*), agave (*Agave* spp.), and durians (*Durio* spp.) they rely on bats for pollination [57]. Durian, a wildly popular fruit worth more than \$230 million per year in Southeast Asia, opens its flower at dusk and relies almost exclusively on fruit bats for pollination [57]. In general, according to the vital role that bats play in the global pollination services, their total economic value is up to \$200 billion [75]. Furthermore, bats have a tremendous economic value in maintaining forests through dispersing the seeds of crucial plants for forest reemerging [76]. For instance, the estimated economic value of bat seed dispersal services to giant oak (*Quercus virginiana*) is \$212,000 for acorn seeding and \$945,000 for planting saplings [77].

Bats provide some of the world's finest natural fertilizers known as Guano [78]. Since there are high concentrations of nitrogen and phosphorous in guano [79], it provides some of the world's finest natural fertilizers [78]. For instance, in Texas the Brazilian free-tailed bat guano has been extracted for fertilizer in thousands of tons from Bracken Cave alone with the current retail sales ranging from \$2.86 to \$12.10 per kilogram [78].

Finally, it is important to recognize the extraordinary value of bats to ancient and contemporary traditions and science. Recently, bats provide esthetic contributions through cave visits, nocturnal tours in national parks, and educational nature programs. Like other wildlife recreational activities, bat watching is considerably growing [80]. Besides providing adventure and life memories to the public, it generates income for the communities and companies involved [80]. For instance, Congress Avenue Bridge, one of the largest urban bat colonies in the USA, is visited by 200–1500 visitors every evening with a value of \$3 million per year [80, 81]. Bats also commonly appear as symbols or logos in popular movies (e.g., Batman), products (e.g., Bacardi rum), and holidays (e.g., Halloween), and all major revenue-generating endeavors [82]. Moreover, many novel technological advances have been inspired by bat echolocation and locomotion, such as sonar systems, biomedical ultrasound, sensors for autonomous systems, wireless communication, and BATMAVs (bat-like motorized aerial vehicles) [83]. Also, in the medical sector, the saliva of vampire bats with its anticlotting chemicals has been investigated as a potential anticoagulant for people who are at high risk of blood clots and strokes [84].

Although, some of these services provide direct benefits to humans (e.g., food, fuel, fiber, and fertilizer), most ecosystem services offer indirect benefits (e.g., pest suppression, seed dispersal, and pollination). Often, little attention is paid to "free" services provided by ecosystems either because the benefits of the services are not fully understood by decision makers or because the benefits accrue to non-owners of the ecosystem providing the service [48]. Information on nonmarket values of ecosystem services can be used to inform decisions regarding whether to protect existing ecosystem services, improve the current provision of ecosystem services, or restore previously lost ecosystem services [4, 85].

Finally, although much of the public and some policy makers may view the precipitous decline of bats worldwide as only of academic interest, the economic and ecological consequences of losing so many bats could be substantial. Thus, a deeper understanding

**Figure 3.** *Ecosystem services provided by bats by Ramírez-Fráncel [86].*

of bat-human inter-relationships, the importance of bat diversity, and ecosystem management is crucial for healthy ecosystems and human well-being (**Figure 3**).
