Surveillance is used by governments for intelligence gathering, prevention of crime, the protection of a process, person, group or object, or the investigation of crime. It is also used by criminal organisations to plan and commit crimes, such as robbery and kidnapping, by businesses to gather intelligence, and by private investigators.
Surveillance can be viewed as a violation of privacy, and as such is often opposed by various civil liberties groups and activists.Liberal democracies have laws which restrict domestic government and private use of surveillance, usually limiting it to circumstances where public safety is at risk. Authoritarian government seldom have any domestic restrictions, and international espionage is common among all types of countries.
The area of surveillance is increasingly a topic of academic study, including through research centers, books, and peer-reviewed academic journals. "In the future, intelligence services might use the internet of things for identification, surveillance, monitoring, location tracking, and targeting for recruitment, or to gain access to networks or user credentials," Clapper said.
There is far too much data on the Internet for human investigators to manually search through all of it. Therefore, automated Internet surveillance computers sift through the vast amount of intercepted Internet traffic to identify and report to human investigators the traffic that is considered interesting or suspicious. This process is regulated by targeting certain "trigger" words or phrases, visiting certain types of web sites, or communicating via email or online chat with suspicious individuals or groups. Billions of dollars per year are spent by agencies, such as the NSA, the FBI and the now-defunct Information Awareness Office, to develop, purchase, implement, and operate systems such as Carnivore, NarusInsight, and ECHELON to intercept and analyze all of this data to only extract the information which is useful to law enforcement and intelligence agencies.
Computers can be a surveillance target because of the personal data stored on them. If someone is able to install software, such as the FBI's Magic Lantern and CIPAV, on a computer system, they can easily gain unauthorized access to this data. Such software could be installed physically or remotely. Another form of computer surveillance, known as van Eck phreaking, involves reading electromagnetic emanations from computing devices in order to extract data from them at distances of hundreds of meters. The NSA runs a database known as "Pinwale", which stores and indexes large numbers of emails of both American citizens and foreigners. Additionally, the NSA runs a program known as PRISM, which is a data mining system that gives the United States government direct access to information from technology companies. Through accessing this information, the government is able to obtain search history, emails, stored information, live chats, file transfers, and more. This program generated huge controversies in regards to surveillance and privacy, especially from U.S. citizens.
The official and unofficial tapping of telephone lines is widespread. In the United States for instance, the Communications Assistance For Law Enforcement Act (CALEA) requires that all telephone and VoIP communications be available for real-time wiretapping by Federal law enforcement and intelligence agencies. Two major telecommunications companies in the U.S.—AT&T Inc. and Verizon—have contracts with the FBI, requiring them to keep their phone call records easily searchable and accessible for Federal agencies, in return for $1.8 million per year. Between 2003 and 2005, the FBI sent out more than 140,000 "National Security Letters" ordering phone companies to hand over information about their customers' calling and Internet histories. About half of these letters requested information on U.S. citizens.
Human agents are not required to monitor most calls. Speech-to-text software creates machine-readable text from intercepted audio, which is then processed by automated call-analysis programs, such as those developed by agencies such as the Information Awareness Office, or companies such as Verint, and Narus, which search for certain words or phrases, to decide whether to dedicate a human agent to the call.
Law enforcement and intelligence services in the United Kingdom and the United States possess technology to activate the microphones in cell phones remotely, by accessing phones' diagnostic or maintenance features in order to listen to conversations that take place near the person who holds the phone.
The StingRay tracker is an example of one of these tools used to monitor cell phone usage in the United States and the United Kingdom. Originally developed for counterterrorism purposes by the military, they work by broadcasting powerful signals that cause nearby cell phones to transmit their IMSI number, just as they would to normal cell phone towers. Once the phone is connected to the device, there is no way for the user to know that they are being tracked. The operator of the stingray is able to extract information such as location, phone calls, and text messages, but it is widely believed that the capabilities of the StingRay extend much further. A lot of controversy surrounds the StingRay because of its powerful capabilities and the secrecy that surrounds it.
Mobile phones are also commonly used to collect location data. The geographical location of a mobile phone (and thus the person carrying it) can be determined easily even when the phone is not being used, using a technique known as multilateration to calculate the differences in time for a signal to travel from the cell phone to each of several cell towers near the owner of the phone. The legality of such techniques has been questioned in the United States, in particular whether a court warrant is required. Records for one carrier alone (Sprint), showed that in a given year federal law enforcement agencies requested customer location data 8 million times.
In response to customers' privacy concerns in the post Edward Snowden era, Apple's iPhone 6 has been designed to disrupt investigative wiretapping efforts. The phone encrypts e-mails, contacts, and photos with a code generated by a complex mathematical algorithm that is unique to an individual phone, and is inaccessible to Apple. The encryption feature on the iPhone 6 has drawn criticism from FBI director James B. Comey and other law enforcement officials since even lawful requests to access user content on the iPhone 6 will result in Apple supplying "gibberish" data that requires law enforcement personnel to either break the code themselves or to get the code from the phone's owner. Because the Snowden leaks demonstrated that American agencies can access phones anywhere in the world, privacy concerns in countries with growing markets for smart phones have intensified, providing a strong incentive for companies like Apple to address those concerns in order to secure their position in the global market.
Although the CALEA requires telecommunication companies to build into their systems the ability to carry out a lawful wiretap, the law has not been updated to address the issue of smart phones and requests for access to e-mails and metadata. The Snowden leaks show that the NSA has been taking advantage of this ambiguity in the law by collecting metadata on "at least hundreds of millions" of "incidental" targets from around the world. The NSA uses an analytic tool known as CO-TRAVELER in order to track people whose movements intersect and to find any hidden connections with persons of interest.
The Snowden leaks have also revealed that the British Government Communications Headquarters (GCHQ) can access information collected by the NSA on American citizens. Once the data has been collected, the GCHQ can hold on to it for up to two years. The deadline can be extended with the permission of a "senior UK official".
Surveillance cameras such as these are installed by the millions in many countries, and are nowadays monitored by automated computer programs instead of humans.
Surveillance cameras are video cameras used for the purpose of observing an area. They are often connected to a recording device or IP network, and may be watched by a security guard or law enforcement officer. Cameras and recording equipment used to be relatively expensive and required human personnel to monitor camera footage, but analysis of footage has been made easier by automated software that organizes digital video footage into a searchable database, and by video analysis software (such as VIRAT and HumanID). The amount of footage is also drastically reduced by motion sensors which only record when motion is detected. With cheaper production techniques, surveillance cameras are simple and inexpensive enough to be used in home security systems, and for everyday surveillance.
There are about 350 million surveillance cameras worldwide as of 2016. About 65% of these cameras are installed in Asia. The growth of CCTV has been slowing in recent years. In 2018, China was reported to have a huge surveillance network of over 170 million CCTV cameras with 400 million new cameras expected to be installed in the next three years, many of which use facial recognition technology.
In the United States, the Department of Homeland Security awards billions of dollars per year in Homeland Security grants for local, state, and federal agencies to install modern video surveillance equipment. For example, the city of Chicago, Illinois, recently used a $5.1 million Homeland Security grant to install an additional 250 surveillance cameras, and connect them to a centralized monitoring center, along with its preexisting network of over 2000 cameras, in a program known as Operation Virtual Shield. Speaking in 2009, Chicago Mayor Richard Daley announced that Chicago would have a surveillance camera on every street corner by the year 2016.
In the United Kingdom, the vast majority of video surveillance cameras are not operated by government bodies, but by private individuals or companies, especially to monitor the interiors of shops and businesses. According to 2011 Freedom of Information Act requests, the total number of local government operated CCTV cameras was around 52,000 over the entirety of the UK. The prevalence of video surveillance in the UK is often overstated due to unreliable estimates being requoted; for example one report in 2002 extrapolated from a very small sample to estimate the number of cameras in the UK at 4.2 million (of which 500,000 in Greater London[Note 1]). More reliable estimates put the number of private and local government operated cameras in the United Kingdom at around 1.85 million in 2011.
In the Netherlands, one example city where there are cameras is The Hague. There, cameras are placed in city districts in which the most illegal activity is concentrated. Examples are the red-light districts and the train stations.
As part of China's Golden Shield Project, several U.S. corporations, including IBM, General Electric, and Honeywell, have been working closely with the Chinese government to install millions of surveillance cameras throughout China, along with advanced video analytics and facial recognition software, which will identify and track individuals everywhere they go. They will be connected to a centralized database and monitoring station, which will, upon completion of the project, contain a picture of the face of every person in China: over 1.3 billion people. Lin Jiang Huai, the head of China's "Information Security Technology" office (which is in charge of the project), credits the surveillance systems in the United States and the U.K. as the inspiration for what he is doing with the Golden Shield Project.
A payload surveillance camera manufactured by Controp and distributed to the U.S. government by ADI Technologies
The Defense Advanced Research Projects Agency (DARPA) is funding a research project called Combat Zones That See that will link up cameras across a city to a centralized monitoring station, identify and track individuals and vehicles as they move through the city, and report "suspicious" activity (such as waving arms, looking side-to-side, standing in a group, etc.).
At Super Bowl XXXV in January 2001, police in Tampa, Florida, used Identix's facial recognition software, FaceIt, to scan the crowd for potential criminals and terrorists in attendance at the event (it found 19 people with pending arrest warrants).
Governments often initially claim that cameras are meant to be used for traffic control, but many of them end up using them for general surveillance. For example, Washington, D.C. had 5,000 "traffic" cameras installed under this premise, and then after they were all in place, networked them all together and then granted access to the Metropolitan Police Department, so they could perform "day-to-day monitoring".
The development of centralized networks of CCTV cameras watching public areas – linked to computer databases of people's pictures and identity (biometric data), able to track people's movements throughout the city, and identify whom they have been with – has been argued by some to present a risk to civil liberties.Trapwire is an example of such a network.
Jason Ethier of Northeastern University, in his study of modern social network analysis, said the following of the Scalable Social Network Analysis Program developed by the Information Awareness Office:
The purpose of the SSNA algorithms program is to extend techniques of social network analysis to assist with distinguishing potential terrorist cells from legitimate groups of people.... In order to be successful SSNA will require information on the social interactions of the majority of people around the globe. Since the Defense Department cannot easily distinguish between peaceful citizens and terrorists, it will be necessary for them to gather data on innocent civilians as well as on potential terrorists.
AT&T developed a programming language called "Hancock", which is able to sift through enormous databases of phone call and Internet traffic records, such as the NSA call database, and extract "communities of interest"—groups of people who call each other regularly, or groups that regularly visit certain sites on the Internet. AT&T originally built the system to develop "marketing leads", but the FBI has regularly requested such information from phone companies such as AT&T without a warrant, and, after using the data, stores all information received in its own databases, regardless of whether or not the information was ever useful in an investigation.
Some people believe that the use of social networking sites is a form of "participatory surveillance", where users of these sites are essentially performing surveillance on themselves, putting detailed personal information on public websites where it can be viewed by corporations and governments. In 2008, about 20% of employers reported using social networking sites to collect personal data on prospective or current employees.
Fingerprints being scanned as part of the US-VISIT program
Biometric surveillance is a technology that measures and analyzes human physical and/or behavioral characteristics for authentication, identification, or screening purposes. Examples of physical characteristics include fingerprints, DNA, and facial patterns. Examples of mostly behavioral characteristics include gait (a person's manner of walking) or voice.
Another form of behavioral biometrics, based on affective computing, involves computers recognizing a person's emotional state based on an analysis of their facial expressions, how fast they are talking, the tone and pitch of their voice, their posture, and other behavioral traits. This might be used for instance to see if a person's behavior is suspect (looking around furtively, "tense" or "angry" facial expressions, waving arms, etc.).
A more recent development is DNA profiling, which looks at some of the major markers in the body's DNA to produce a match. The FBI is spending $1 billion to build a new biometric database, which will store DNA, facial recognition data, iris/retina (eye) data, fingerprints, palm prints, and other biometric data of people living in the United States. The computers running the database are contained in an underground facility about the size of two American football fields.
The Los Angeles Police Department is installing automated facial recognition and license plate recognition devices in its squad cars, and providing handheld face scanners, which officers will use to identify people while on patrol.
Facial thermographs are in development, which allow machines to identify certain emotions in people such as fear or stress, by measuring the temperature generated by blood flow to different parts of the face. Law enforcement officers believe that this has potential for them to identify when a suspect is nervous, which might indicate that they are hiding something, lying, or worried about something.
Digital imaging technology, miniaturized computers, and numerous other technological advances over the past decade have contributed to rapid advances in aerial surveillance hardware such as micro-aerial vehicles, forward-looking infrared, and high-resolution imagery capable of identifying objects at extremely long distances. For instance, the MQ-9 Reaper, a U.S. drone plane used for domestic operations by the Department of Homeland Security, carries cameras that are capable of identifying an object the size of a milk carton from altitudes of 60,000 feet, and has forward-looking infrared devices that can detect the heat from a human body at distances of up to 60 kilometers. In an earlier instance of commercial aerial surveillance, the Killington Mountain ski resort hired 'eye in the sky' aerial photography of its competitors' parking lots to judge the success of its marketing initiatives as it developed starting in the 1950s.
HART program concept drawing from official IPTO (DARPA) official website
In addition to their surveillance capabilities, MAVs are capable of carrying tasers for "crowd control", or weapons for killing enemy combatants.
Programs such as the Heterogeneous Aerial Reconnaissance Team program developed by DARPA have automated much of the aerial surveillance process. They have developed systems consisting of large teams drone planes that pilot themselves, automatically decide who is "suspicious" and how to go about monitoring them, coordinate their activities with other drones nearby, and notify human operators if something suspicious is occurring. This greatly increases the amount of area that can be continuously monitored, while reducing the number of human operators required. Thus a swarm of automated, self-directing drones can automatically patrol a city and track suspicious individuals, reporting their activities back to a centralized monitoring station.
In addition, researchers also investigate possibilities of autonomous surveillance by large groups of micro aerial vehicles stabilized by decentralized bio-inspired swarming rules.
Data mining and profiling
Data mining is the application of statistical techniques and programmatic algorithms to discover previously unnoticed relationships within the data. Data profiling in this context is the process of assembling information about a particular individual or group in order to generate a profile — that is, a picture of their patterns and behavior. Data profiling can be an extremely powerful tool for psychological and social network analysis. A skilled analyst can discover facts about a person that they might not even be consciously aware of themselves.
Economic (such as credit card purchases) and social (such as telephone calls and emails) transactions in modern society create large amounts of stored data and records. In the past, this data was documented in paper records, leaving a "paper trail", or was simply not documented at all. Correlation of paper-based records was a laborious process—it required human intelligence operators to manually dig through documents, which was time-consuming and incomplete, at best.
But today many of these records are electronic, resulting in an "electronic trail". Every use of a bank machine, payment by credit card, use of a phone card, call from home, checked out library book, rented video, or otherwise complete recorded transaction generates an electronic record. Public records—such as birth, court, tax and other records—are increasily being digitized and made available online. In addition, due to laws like CALEA, web traffic and online purchases are also available for profiling. Electronic record-keeping makes data easily collectable, storable, and accessible—so that high-volume, efficient aggregation and analysis is possible at significantly lower costs.
Information relating to many of these individual transactions is often easily available because it is generally not guarded in isolation, since the information, such as the title of a movie a person has rented, might not seem sensitive. However, when many such transactions are aggregated they can be used to assemble a detailed profile revealing the actions, habits, beliefs, locations frequented, social connections, and preferences of the individual. This profile is then used, by programs such as ADVISE and TALON, to determine whether the person is a military, criminal, or political threat.
In addition to its own aggregation and profiling tools, the government is able to access information from third parties — for example, banks, credit companies or employers, etc. — by requesting access informally, by compelling access through the use of subpoenas or other procedures, or by purchasing data from commercial data aggregators or data brokers. The United States has spent $370 million on its 43 planned fusion centers, which are national network of surveillance centers that are located in over 30 states. The centers will collect and analyze vast amounts of data on U.S. citizens. It will get this data by consolidating personal information from sources such as state driver's licensing agencies, hospital records, criminal records, school records, credit bureaus, banks, etc. – and placing this information in a centralized database that can be accessed from all of the centers, as well as other federal law enforcement and intelligence agencies.
Corporate surveillance is the monitoring of a person or group's behavior by a corporation. The data collected is most often used for marketing purposes or sold to other corporations, but is also regularly shared with government agencies. It can be used as a form of business intelligence, which enables the corporation to better tailor their products and/or services to be desirable by their customers. Although there is a common belief that monitoring can increase productivity, it can also create consequences such as increasing chances of deviant behavior and creating punishments that are not equitable to their actions. Additionally, monitoring can cause resistance and backlash because it insinuates an employer’s suspicion and lack of trust.
Data collected on individuals and groups can be sold to other corporations, so that they can use it for the aforementioned purpose. It can be used for direct marketing purposes, such as targeted advertisements on Google and Yahoo. These ads are tailored to the individual user of the search engine by analyzing their search history and emails (if they use free webmail services), which is kept in a database.
For instance, Google, the world's most popular search engine, stores identifying information for each web search. An IP address and the search phrase used are stored in a database for up to 18 months. Google also scans the content of emails of users of its Gmail webmail service, in order to create targeted advertising based on what people are talking about in their personal email correspondences. Google is, by far, the largest Internet advertising agency. Their revenue model is based on receiving payments from advertisers for each page-visit resulting from a visitor clicking on a Google AdWords ad, hosted either on a Google service or a third-party website. Millions of sites place Google's advertising banners and links on their websites, in order to share this profit from visitors who click on the ads. Each page containing Google advertisements adds, reads, and modifies "cookies" on each visitor's computer. These cookies track the user across all of these sites, and gather information about their web surfing habits, keeping track of which sites they visit, and what they do when they are on these sites. This information, along with the information from their email accounts, and search engine histories, is stored by Google to use for building a profile of the user to deliver better-targeted advertising.
According to the American Management Association and the ePolicy Institute that undertake an annual quantitative survey about electronic monitoring and surveillance with approximately 300 U.S. companies, "more than one fourth of employers have fired workers for misusing e-mail and nearly one third have fired employees for misusing the Internet". More than 40% of the companies monitor e-mail traffic of their workers, and 66% of corporations monitor Internet connections. In addition, most companies use software to block non-work related websites such as sexual or pornographic sites, game sites, social networking sites, entertainment sites, shopping sites, and sport sites. The American Management Association and the ePolicy Institute also stress that companies "tracking content, keystrokes, and time spent at the keyboard ... store and review computer files ... monitor the blogosphere to see what is being written about the company, and ... monitor social networking sites". Furthermore, about 30% of the companies had also fired employees for non-work related email and Internet usage such as "inappropriate or offensive language" and "viewing, downloading, or uploading inappropriate/offensive content".
Government Use of Corporate Surveillance Data
The United States government often gains access to these databases, either by producing a warrant for it, or by simply asking. The Department of Homeland Security has openly stated that it uses data collected from consumer credit and direct marketing agencies—such as Google—for augmenting the profiles of individuals whom it is monitoring. The FBI, Department of Homeland Security, and other intelligence agencies have formed an "information-sharing" partnership with over 34,000 corporations as part of their Infragard program.
The U.S. Federal government has gathered information from grocery store "discount card" programs, which track customers' shopping patterns and store them in databases, in order to look for "terrorists" by analyzing shoppers' buying patterns.
Organizations that have enemies who wish to gather information about the groups' members or activities face the issue of infiltration.
In addition to operatives' infiltrating an organization, the surveilling party may exert pressure on certain members of the target organization to act as informants (i.e., to disclose the information they hold on the organization and its members).
Fielding operatives is very expensive, and for governments with wide-reaching electronic surveillance tools at their disposal the information recovered from operatives can often be obtained from less problematic forms of surveillance such as those mentioned above. Nevertheless, human infiltrators are still common today. For instance, in 2007 documents surfaced showing that the FBI was planning to field a total of 15,000 undercover agents and informants in response to an anti-terrorism directive sent out by George W. Bush in 2004 that ordered intelligence and law enforcement agencies to increase their HUMINT capabilities.
One of the simplest forms of identification is the carrying of credentials. Some nations have an identity card system to aid identification, whilst others are considering it but face public opposition. Other documents, such as passports, driver's licenses, library cards, banking or credit cards are also used to verify identity.
If the form of the identity card is "machine-readable", usually using an encoded magnetic stripe or identification number (such as a Social Security number), it corroborates the subject's identifying data. In this case it may create an electronic trail when it is checked and scanned, which can be used in profiling, as mentioned above.
RFID and geolocation devices
Hand with planned insertion point for Verichip device
Radio Frequency Identification (RFID) tagging is the use of very small electronic devices (called "RFID tags") which are applied to or incorporated into a product, animal, or person for the purpose of identification and tracking using radio waves. The tags can be read from several meters away. They are extremely inexpensive, costing a few cents per piece, so they can be inserted into many types of everyday products without significantly increasing the price, and can be used to track and identify these objects for a variety of purposes.
Some companies appear to be "tagging" their workers by incorporating RFID tags in employee ID badges. Workers in U.K. considered strike action in protest of having themselves tagged; they felt that it was dehumanizing to have all of their movements tracked with RFID chips.[vague] Some critics have expressed fears that people will soon be tracked and scanned everywhere they go. On the other hand, RFID tags in newborn baby ID bracelets put on by hospitals have foiled kidnappings.
RFID chip pulled from new credit card
Verichip is an RFID device produced by a company called Applied Digital Solutions (ADS). Verichip is slightly larger than a grain of rice, and is injected under the skin. The injection reportedly feels similar to receiving a shot. The chip is encased in glass, and stores a "VeriChip Subscriber Number" which the scanner uses to access their personal information, via the Internet, from Verichip Inc.'s database, the "Global VeriChip Subscriber Registry". Thousands of people have already had them inserted. In Mexico, for example, 160 workers at the Attorney General's office were required to have the chip injected for identity verification and access control purposes.
In a 2003 editorial, CNET News.com's chief political correspondent, Declan McCullagh, speculated that, soon, every object that is purchased, and perhaps ID cards, will have RFID devices in them, which would respond with information about people as they walk past scanners (what type of phone they have, what type of shoes they have on, which books they are carrying, what credit cards or membership cards they have, etc.). This information could be used for identification, tracking, or targeted marketing. As of 2012, this has largely not come to pass.
In the U.S., police have planted hidden GPS tracking devices in people's vehicles to monitor their movements, without a warrant. In early 2009, they were arguing in court that they have the right to do this.
Several cities are running pilot projects to require parolees to wear GPS devices to track their movements when they get out of prison.
Mobile phones are also commonly used to collect geolocation data. The geographical location of a mobile phone (and thus the person carrying it) can be determined easily (whether it is being used or not), using a technique known multilateration to calculate the differences in time for a signal to travel from the cell phone to each of several cell towers near the owner of the phone. Dr. Victor Kappeler of Eastern Kentucky University indicates that police surveillance is a strong concern, stating the following statistics from 2013:
Of the 321,545 law enforcement requests made to Verizon, 54,200 of these requests were for "content" or "location" information—not just cell phone numbers or IP addresses. Content information included the actual text of messages, emails and the wiretapping of voice or messaging content in real-time.
A comparatively new off-the-shelf surveillance device is an IMSI-catcher, a telephone eavesdropping device used to intercept mobile phone traffic and track the movement of mobile phone users. Essentially a "fake" mobile tower acting between the target mobile phone and the service provider's real towers, it is considered a man-in-the-middle (MITM) attack. IMSI-catchers are used in some countries by law enforcement and intelligence agencies, but their use has raised significant civil liberty and privacy concerns and is strictly regulated in some countries.
A human microchip implant is an identifying integrated circuit device or RFID transponder encased in silicate glass and implanted in the body of a human being. A subdermal implant typically contains a unique ID number that can be linked to information contained in an external database, such as personal identification, medical history, medications, allergies, and contact information.
Several types of microchips have been developed in order to control and monitor certain types of people, such as criminals, political figures and spies,[clarification needed] a "killer" tracking chip patent was filed at the German Patent and Trademark Office (DPMA) around May 2009.
Law enforcement and intelligence services in the U.K. and the United States possess technology to remotely activate the microphones in cell phones, by accessing the phone's diagnostic/maintenance features, in order to listen to conversations that take place nearby the person who holds the phone.
As more people use faxes and e-mail the significance of surveilling the postal system is decreasing, in favor of Internet and telephone surveillance. But interception of post is still an available option for law enforcement and intelligence agencies, in certain circumstances. This is not a common practice, however, and entities like the US Army require high levels of approval to conduct.
A stakeout is the coordinated surveillance of a location or person. Stakeouts are generally performed covertly and for the purpose of gathering evidence related to criminal activity. The term derives from the practice by land surveyors of using survey stakes to measure out an area before the main building project is commenced.
The management of wildlife populations often requires surveillance. This includes, for example surveillance of (1) Invasive species location and abundance for more effective management, (2) illegal fishers and poachers to reduce harvest and overexploitation of natural resources, (3) the population abundances of endangered species to decrease the risk of extinction, and (4) wildlife diseases that can damange crops, agriculture and natural populations.