Urban plain ecological environment change monitoring method based on small mammal survey

Abstract

The invention discloses an urban plain ecological environment change monitoring method based on small mammal survey. The method comprises the following steps: firstly, determining a long-eared owl pill collection point, and then obtaining the coverage area proportion, biomass and vascular plant species richness of forests, shrubs, grassland and cultivated land in a predation range area; then calculating biological diversity index measurement parameters based on the long-eared owl food pills: species richness of predated animals, occurrence frequency of the predated animals in the food pills, predation intensity of the predated animals and biomass proportion of the predated animals; and finally, calculating a comprehensive index of the ecological environment quality of the urban plain area based on the indexes to determine the ecological environment change condition of the urban plain area. By using the method, the problem that the biological diversity of the small mammals cannot be observed for a long time is solved, and a technical support is provided for observing and judging the comprehensive quality change condition of the urban ecological environment for a long time by virtue of the small mammals with a relatively good indication effect.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental protection and monitoring, and in particular relates to a method for monitoring changes in the ecological environment of an urban plain based on a survey of small mammals. Background Art

[0002] The plain area of ​​the city is the hub and important node of the ecological corridor between the mountainous area and the central urban area. There are a large number of farmlands and a certain amount of wilderness, providing unique habitat types different from those in the mountainous area and the central urban area. It plays an irreplaceable role in biodiversity conservation. It has been the main implementation area of ​​ecological construction in the city for more than ten years. It is an important node area of ​​the urban ecological corridor and has great potential for biodiversity restoration. In the plain area, the number and species of small mammals are dominant among mammals, and there are almost no large mammals. Therefore, small mammals are the protagonists of the ecological environment in the urban plain area.

[0003] In addition, using small mammals as indicator species to measure changes in the urban ecological environment has many advantages. First, when the ecological environment changes, small mammals in the urban ecological environment are neither overly sensitive like insects nor have a long time lag like large mammals; second, in the urban ecological environment, small mammals are more numerous, are at a relatively high level in the food chain, and often move in groups, which is convenient for observation and quantitative statistical analysis; third, their migration ability is limited and their activity area is relatively narrow, which can better reflect the changes in the ecological environment quality of a certain area. Therefore, selecting small mammals as indicators for monitoring changes in the urban ecological environment can scientifically, accurately and effectively reflect the changes in the comprehensive quality of the urban ecological environment.

[0004] However, different small mammal survey and monitoring methods have a great impact on the monitoring results of changes in the comprehensive quality of the ecological environment. By combing through domestic and foreign reference materials, the commonly used small mammal survey and monitoring methods mainly include line sampling survey method, infrared camera shooting method, Sherman trap method, Longworth trap method, cage trap method, harp net trap method, resident interview method, call playback method, spotlight search method, echolocation call detection method and trace search method.

[0005] For example, the line transect method requires observing and recording mammals and their activity traces that appear along a selected route and on both sides of the line. The line transect is usually 1-5 kilometers long, which requires the survey team not only to spend a lot of time and physical energy, but also that the survey can only be conducted during the day. For small mammals that are more active at night, only individual activity traces can be found, and the species cannot be identified, and the number and species richness of small mammals in the area cannot be accurately estimated.

[0006] Infrared camera automatic photography refers to a survey method in which observers use infrared sensing automatic cameras, hereinafter referred to as infrared cameras, to automatically record images of animals moving within its sensing range. Infrared camera photography is widely used in mammal surveys, but the infrared camera method not only has extremely high equipment procurement and maintenance costs, but also for small mammals that are active at night and move quickly, the images will be distorted, and clear image data cannot be obtained, resulting in the inability to identify species and the inability to obtain the number and species richness of the survey area.

[0007] Cage capture, trap capture, and net capture all require the capture of small mammals. During the survey, first, small mammals may die during the sampling process; second, damaging sampling requires application to relevant departments for sampling, which is cumbersome and cannot be carried out at any time; third, long-term monitoring in the same area requires repeated damaging sampling, which has a great impact on the number and species of small mammals in the area, and cannot accurately assess the regional ecological environment quality.

[0008] In addition, non-destructive sampling refers to a survey method that collects shed hair, feces, urine, food residues or other appendages without touching or harming the mammals themselves. This method is suitable for long-term monitoring, but collecting shed hair, feces, urine, food residues or other appendages cannot accurately identify the species of small mammals.

[0009] Through one-by-one analysis, we found that the traditional small mammal survey and monitoring methods at home and abroad are not suitable for long-term monitoring of the ecological environment in urban plains. We need to develop a new, effective, low-cost, and scientific method as a method for urban ecological environment monitoring.

[0010] All Strigiformes birds feed on animals, including small mammals, small birds, insects, earthworms, frogs, lizards, etc. Take the long-eared owl that winters in Beijing as an example. Its main food is rodents, chiropterans and small birds. The long-eared owl swallows its prey whole, and after digestion, it spits out the unabsorbed fur, bones, chitin and other debris in a ball shape, which is called a food ball. The food ball has various shapes, including ellipsoid, spherical, oblate and irregular shapes, and is dark gray or grayish white in color. The surface of the fresh food ball just spit out has a film similar to saliva. The contents of some food balls, such as bones, are exposed. Some food balls are peeled into powder and scattered, while others are tightly bound by animal hair. According to research, the contents of the long-eared owl's food ball include: bones of animals and birds, bird feathers, animal hair, incompletely digested rodents, wheat grains, plant seeds, etc. Wang Junfu's research on long-eared owls in Shanghai found that the time of long-eared owls' regurgitation of food boluses was not fixed every day. The time interval between regurgitation of food boluses was not fixed between 8:30 and 17:00. According to statistical analysis, the number of skulls of animals in a single complete food bolus of long-eared owls ranged from 0 to 4, and the number of skulls in a food bolus containing 1 to 2 skulls accounted for 64.43%. A single long-eared owl regurgitated 1 to 3 skulls separated from its food bolus per day, which means that a single long-eared owl preyed on 1 to 3 animals per day.

[0011] By collecting, processing and identifying the pellets of long-eared owls, it is possible to easily obtain the number and species richness of small mammals in an area. However, in existing technologies, most of the research on long-eared owls, except for the research on their own biology, focuses on bionics, and no research has been found on their use in environmental monitoring. Summary of the invention

[0012] The main purpose of the present invention is to design a method for monitoring ecological environment changes in urban plain areas based on small mammals. The method will use the content of the food pellets of the long-eared owl of the order Strigiformes to obtain the quantity and type data of small mammals in the area, so as to monitor the changes in the comprehensive quality of the regional ecological environment. It is expected to provide technical support for judging the changes in the comprehensive quality of the urban ecological environment by relying on long-term observation of small mammals with good indication. The purpose of the present invention is achieved through the following technical solutions:

[0013] A method for monitoring ecological environment changes in urban plains based on small mammal surveys includes the following steps:

[0014] Step 1: Determine the collection point for long-eared owl pellets;

[0015] Step 2: Obtain the coverage area percentage and biomass of forests, bushes, grasslands, and cultivated land within the predation range: Take the long-eared owl pellet collection point as the center point and 10 km as the radius to obtain the long-eared owl's predation range. Obtain the coverage area percentage and biomass of forests, bushes, grasslands, and cultivated land in the region through remote sensing interpretation once a year;

[0016] Step 3: Obtain the species richness of vascular plants in forests, shrubs, and grasslands within the predation range: In July and August of the year following the observation of the long-eared owl, set up vegetation survey plots within a 3-kilometer range with the long-eared owl food pellet collection point as the center point. The plots are 10m*10m, including types: grassland, shrubs, and tree forests. There are no less than 3 plots of each type. The basic information in the plots is investigated and recorded to obtain the species richness of vascular plants in forests, shrubs, and grasslands in the area. The vegetation habitat quality information of the plots is retested from July to August every year;

[0017] Step 4: Food pellet collection: From November of the current year to March of the following year, food pellets are collected every two weeks. During the collection process, the distribution location and number of long-eared owls are recorded, and the food pellets are measured and numbered.

[0018] Step 5: Food pellet separation: In a petri dish, separate each bone with forceps;

[0019] Step 6: Count the number of animals eaten by the pellets: determine the number of small mammals eaten based on the number of maxillary and mandibular pairs obtained; determine the number of birds eaten based on the number of undigested beaks, skulls or claws;

[0020] Step 7: Species identification of small mammals that are preyed on: After determining the number of animals, identify the bones and incisor positions of each animal to determine the order to which the small mammal belongs; and identify the rodents, chiropterans, and laurasiana insectivores to the species level;

[0021] Step 8: Identify the prey birds by species and order;

[0022] Step 9: Establish a weight query table of prey caught by long-tailed owls through literature search;

[0023] Step 10: Based on the work of steps 4 to 9, calculate the biodiversity index measurement parameters: species richness of prey animals, frequency of prey animals in food pellets, intensity of prey animals being preyed on, and biomass ratio of prey animals;

[0024] Step 11: Calculate the comprehensive index of ecological environment quality in urban plain areas:

[0025] It covers two primary indicators: vegetation cover index and biodiversity index;

[0026] The vegetation coverage index consists of four secondary indicators, namely, forest index, shrub index, grassland index, and cultivated land index; the biodiversity index consists of four secondary indicators, namely, species diversity index of prey animals, frequency index of prey animals in food pellets, prey intensity index of prey animals, and biomass ratio index of prey animals; each secondary indicator has different calculation parameters:

[0027] The calculation parameters of the secondary indicator forest index are: the coverage area percentage, biomass and vascular plant species richness of tree forests in the region; the calculation parameters of the secondary indicator shrub index are: the coverage area percentage, biomass and vascular plant species richness of shrubs in the region; the calculation parameters of the secondary indicator grassland index are: the coverage area percentage, biomass and vascular plant species richness of grassland in the region; the calculation parameters of the secondary indicator cultivated land index are: the coverage area percentage of cultivated land in the region;

[0028] The calculation parameters of the secondary indicator of species diversity index of prey animals are: species richness of rodents, chiropterans, and laurasia insectivores, and birds; the calculation parameters of the secondary indicator of frequency index of prey animals in food pellets are: frequency of occurrence of rodents, chiropterans, and laurasia insectivores, and birds in food pellets; the calculation parameters of the secondary indicator of predator predation intensity index are: predation intensity of rodents, chiropterans, and laurasia insectivores, and birds; the calculation parameters of the secondary indicator of biomass ratio index of prey animals are: biomass ratio of rodents, chiropterans, and laurasia insectivores, and birds;

[0029] The comprehensive index of ecological environment quality in urban plain areas is calculated according to formula (1):

[0030]

[0031] Where:

[0032] UPTEEI is the comprehensive index of ecological environment quality in urban plain areas;

[0033] ω i is the weight of the i-th first-level indicator;

[0034] n is the number of first-level indicators;

[0035] m i is the number of secondary indicators under the i-th primary indicator;

[0036] ω ij is the weight of the jth secondary indicator under the i-th primary indicator;

[0037] l ij is the number of parameters calculated under the jth secondary indicator under the i-th primary indicator;

[0038] ω ijk is the weight of the kth calculation parameter under the jth secondary indicator under the i-th primary indicator;

[0039] I ijk is the evaluation value of the kth calculation parameter under the jth secondary indicator under the ith primary indicator;

[0040] i is the first-level indicator number;

[0041] j is the secondary indicator number;

[0042] k is the number of the evaluation value of the calculation parameter;

[0043] The evaluation value of the calculation parameter is calculated according to formula (2):

[0044]

[0045] Where:

[0046] I ijk is the evaluation value of the kth calculation parameter under the jth secondary indicator under the ith primary indicator;

[0047] X ijk is the measured or estimated value of the kth calculation parameter under the jth secondary indicator under the ith primary indicator;

[0048] X max(ijk) is the maximum value of the kth calculation parameter under the jth secondary indicator under the ith primary indicator during the evaluation period;

[0049] X min(ijk) It is the minimum value of the kth calculation parameter under the jth secondary indicator under the ith primary indicator within the evaluation period;

[0050] Step 12: Compare the changes in ecological environment quality in different regions during the same period based on the comprehensive ecological environment quality index of urban plain areas in different regions; or compare the comprehensive ecological environment quality index of urban plain areas in the same region in different years to determine the changes in the ecological environment of urban plain areas.

[0051] Furthermore, in step one, first select points where long-eared owls have a long-term stable distribution as candidate points for collecting food pellets; the points where long-eared owls have a long-term stable distribution are locations where long-eared owls have appeared for two consecutive years, as determined based on bird watching record data; then go to the candidate points for collecting long-eared owl food pellets to conduct a site survey, and select some of the candidate points as long-eared owl food pellet collection points, with the distance between the two collection points being required to be more than 20 kilometers.

[0052] Further, in step 2, biomass calculation:

[0053] The biomass of the forest is calculated according to formula (3):

[0054] biofor=4.031×ln(LAI)+5.036 (3)

[0055] Where: LAI is the leaf area index; biofor is the forest biomass;

[0056] The biomass of the shrub is calculated according to formula (4):

[0057] bioshrub=4.031×ln(LAI)+5.036 (4)

[0058] Where: bioshrub is the shrub biomass;

[0059] The biomass of grassland is calculated according to formula (5):

[0060] biosgrass=(420.7×RVI+53.594) / 10000 (5)

[0061] Where: RVI is the ratio vegetation index; biosgrass is the grassland biomass;

[0062] The normalized vegetation index of Landsat images calculated based on GEE is as follows:

[0063]

[0064] Where: NDVI is the normalized difference vegetation index; ρ nir is the reflectivity in the near-infrared band; ρ red is the reflectivity of red light band;

[0065] The ratio vegetation index of Landsat images is calculated based on GEE as shown in formula (7):

[0066]

[0067] The vegetation leaf area index is calculated according to formula (8):

[0068] LAI=5.724×NDVI-1.536 (8)

[0069] Furthermore, in step three, the basic information in the sample plot is investigated and recorded, including: vegetation type, vegetation composition, canopy density, altitude, slope, slope aspect, coverage, tree species, breast diameter, tree height, ground diameter, number of clusters, and vitality; the vascular plant species richness (S-vascular plant) adopts the number of vascular plant species appearing in the area.

[0070] Furthermore, in step 4, before collecting the food pills, prepare food pill collection tools: including plastic gloves, 95% alcohol, ziplock bags, label paper, markers, purchased video surveillance systems, field investigation record logs, and vernier calipers.

[0071] Further, in step five, a single pellet was placed in a petri dish, 95% alcohol was added, and each bone was separated using forceps.

[0072] Furthermore, in step seven, the order of small mammals is determined based on the regional small mammal sub-order retrieval table, and the order of small mammals to which each animal belongs is determined based on the bones and incisor position of each animal; based on the tooth pattern of the maxillary teeth and comparing the morphology of the skull in the atlas as a standard, a classification retrieval table is established to identify the species.

[0073] Furthermore, in step eight, the birds are identified to orders based on the remaining beaks, bones and feathers.

[0074] Furthermore, in step 10: the species richness of prey animals is the number of animal species appearing in the food pellet;

[0075] The frequency of prey animals appearing in the food pellets is calculated as follows:

[0076]

[0077] Where: F pi is the frequency of occurrence of the pi-th animal; NP pi is the number of food boluses containing skulls of pi species of animals; NP is the total number of food boluses;

[0078] The formula for calculating the prey intensity of prey animals is as follows:

[0079]

[0080] Where: P pi is the predation intensity of the pi-th animal; N pi is the number of individuals of the pi-th species of animal; N is the total number of individuals of prey animals;

[0081] The biomass ratio of prey animals is calculated as follows:

[0082]

[0083] Where: FB pi is the biomass ratio of the pi-th animal; N pi* is the number of individuals of the pi-th species; B pi is the average weight of the pi-th species of animal; np is the number of prey species.

[0084] The advantages and beneficial effects of the present invention are:

[0085] 1) The use of the method of the present invention solves the problem of being unable to observe the biodiversity of small mammals over a long period of time, and provides technical support for judging the changes in the comprehensive quality of the urban ecological environment by relying on long-term observation of small mammals with good indication effects.

[0086] During the monitoring process from November 2022 to March 2023 and from November 2023 to March 2024, a total of 876 pellets were collected using this method, and the prey identified involved 2 classes, 4 orders, 10 families, 17 genera, 20 species, and 1,734 small mammals and birds. Among them, there were 14 small mammals (including 5 species of rodents, 6 species of chiropteras, and 3 species of laurasia insectivoras) and 6 species of birds. In terms of species composition, rodents accounted for 86.16%; birds accounted for 7.14%; chiropteras accounted for 3.79%; and laurasia insectivoras accounted for 2.91%.

[0087] 2) Compared with traditional survey methods such as cage capture, trap capture, and net capture, the present invention plays an important role in biodiversity conservation, can reduce direct interference, maintain ecological balance, protect sensitive species, etc., and provides strong support for the long-term protection and sustainable utilization of biodiversity, which is specifically manifested in:

[0088] First, it minimizes disturbance to the ecosystem and direct disturbance in environmental monitoring, and minimizes the direct impact of human activities on biodiversity by avoiding direct contact with individual animals and their habitats. This method reduces animal casualties that may be caused by activities such as capture, tagging, and tracking, thereby protecting the population size and genetic diversity of species. Compared with traditional methods, this invention has avoided 1,613 small mammals from facing injuries and deaths due to surveys since its launch, greatly protecting the welfare of animals.

[0089] Second, the present invention has increased the success rate of obtaining small mammal species by 10 species, to 350%. Traditional survey methods are limited by survey environmental conditions and terrain and cannot capture all small mammals. From 2023 to 2024, the project team used the trap method to survey small mammals, setting up a total of 20 survey plots, with 100 traps in each survey plot, and recorded a total of 4 species of small mammals, including the northern rat, brown rat, black-lined field mouse, and house mouse. In the area where the present invention carried out monitoring, a total of 14 species of small mammals were recorded, covering all small mammals in the plain area of ​​Beijing during the wintering season, bringing the species coverage rate of biodiversity surveys to 100%. Compared with the traditional trap method survey coverage rate of only 28%, the effective acquisition rate of biodiversity data has increased by 70%.

[0090] Third, some small mammals are rare and endangered species and are the focus of biodiversity conservation, such as musk mole, Beijing myotis bat, Chinese zorraine, David myotis bat, big-foot myotis bat, etc. On the one hand, they are extremely sensitive to environmental changes. On the other hand, as protected species, destructive invasive surveys cause great psychological pressure and stress response to protected species populations, and affect the normal life and behavior of species groups. The method used in the present invention can obtain effective data on ecological environment changes in plain areas without affecting the normal behavior of animals, which provides the possibility of long-term monitoring and obtaining effective data in the same area.

[0091] In short, the present invention solves the problems existing in the current traditional methods, such as the possibility of causing harm to the survey subjects, the inability to conduct long-term continuous monitoring and investigation due to damaging sampling, the expensive related equipment such as infrared cameras, the traditional investigation consuming a lot of manpower and material resources, the complicated procedures for applying for investigations and the inability to conduct investigations at any time, and the inability to accurately identify the species. DETAILED DESCRIPTION

[0092] Embodiment 1:

[0093] Step 1: Based on the natural geographical profile of Beijing's plain areas and public data (data recorded by the China Bird Watching Record Center), select 10-20 long-eared owl long-term stable distribution points (places where long-eared owls have appeared for two consecutive years) as candidate points for collecting food pellets. Go to the candidate points for collecting long-eared owl food pellets to conduct site surveys, and select 5 points with a large number of long-eared owls from the candidate points as long-eared owl food pellet collection points, with the distance between the two collection points being more than 20 kilometers.

[0094] Step 2: Obtain the coverage area percentage and biomass of forests, bushes, grasslands, and cultivated land within the predation range: Take the long-eared owl pellet collection point as the center point and 10 km as the radius to obtain the long-eared owl's predation range. Obtain the coverage area percentage and biomass of forests, bushes, grasslands, and cultivated land in the region through remote sensing interpretation once a year;

[0095] The biomass of the forest is calculated according to formula (3):

[0096] biofor=4.031×ln(LAI)+5.036 (3)

[0097] Where: LAI is the leaf area index; biofor is the forest biomass;

[0098] The biomass of the shrub is calculated according to formula (4):

[0099] bioshrub=4.031×ln(LAI)+5.036 (4)

[0100] Where: bioshrub is the shrub biomass;

[0101] The biomass of grassland is calculated according to formula (5):

[0102] biosgrass=(420.7×RVI+53.594) / 10000 (5)

[0103] Where: RVI is the ratio vegetation index; biosgrass is the grassland biomass;

[0104] The normalized vegetation index of Landsat images calculated based on GEE is as follows:

[0105]

[0106] Where: NDVI is the normalized difference vegetation index; ρ nir is the reflectivity in the near-infrared band; ρ red is the reflectivity of red light band;

[0107] The ratio vegetation index of Landsat images is calculated based on GEE as shown in formula (7):

[0108]

[0109] The vegetation leaf area index is calculated according to formula (8):

[0110] LAI=5.724×NDVI-1.536 (8)

[0111] Step 3: Obtain the species richness of vascular plants in forests, shrubs, and grasslands within the predation range: In July and August of the following year after the long-eared owl was observed, a vegetation survey plot was set up within a 3-kilometer range with the long-eared owl food pellet collection point as the center point. The plot was 10m*10m, including types: grassland, shrubs, and arbor forests. There were no less than 3 plots of each type. The basic information in the plot was investigated and recorded to obtain the species richness of vascular plants in forests, shrubs, and grasslands in the area. The vegetation habitat quality information of the plot was retested from July to August each year; the vascular plant species richness (S-vascular plant) was the number of vascular plant species that appeared in the area. The arbor forest survey record table is shown in Table 1, the shrub survey record table is shown in Table 2, and the grassland survey record table is shown.

[0112] Table 1

[0113]

[0114]

[0115] Table 2

[0116]

[0117] Table 3

[0118]

[0119]

[0120] Step 4: Food pellet collection: Prepare food pellet collection tools including plastic gloves, 95% alcohol, ziplock bags, label paper, markers, purchase video surveillance systems, field survey log books, and vernier calipers; collect food pellets from November of the current year to March of the following year, collecting food pellets every 2 weeks; during the collection process, keep a record of the distribution location and number of long-eared owls, and keep records of food pellet collection, measurement, and numbering;

[0121] Step 5: Food pellet separation: Place a single food pellet in a petri dish, add 95% alcohol, and separate each bone with tweezers.

[0122] Step six: Count the number of animals involved in the pellets: Determine the number of small mammals eaten based on the number of maxillary pairings and mandible pairings obtained; determine the number of birds eaten by the number of undigested beaks or skulls, or the number of pairs of claws; their skulls include maxilla and mandible, and each animal has a pair of maxilla and a pair of mandible. Pair the maxilla and mandible, and the largest number of pairs is the number of small mammals involved in the pellets. The birds involved in the pellets all have 1 upper beak, 1 lower beak, and 1 pair of claws; take the maximum number of pairs of upper beak, lower beak, and claws to determine the number of birds;

[0123] Step 7: Species identification of small mammals. After determining the number of paired animals, this embodiment uses the Beijing area small mammal suborder retrieval table to determine the order to which the small mammal belongs based on the bones and incisor positions of each animal. Table 4

[0124]

[0125]

[0126] Species identification was performed for rodents, chiropteras and laurasiinsectivora. Based on the tooth pattern of the maxillary teeth and the skull morphology in the atlas, a classification index was established to identify the species. Take rodents as an example.

[0127] Table 5

[0128]

[0129] Step 8: Identify the bird species. Birds are identified to their order based on the remaining beaks, bones and feathers.

[0130] Step 9: Through literature search, establish a query table for the weight of prey caught by long-tailed owls as shown in Table 6.

[0131] Table 6

[0132]

[0133]

[0134] Step 10: Based on the work from Steps 5 to 10, calculate the biodiversity index measurement parameters: species richness of prey animals, frequency of prey animals in food pellets, intensity of prey animals being preyed on, and biomass ratio of prey animals.

[0135] The species richness of prey animals was measured using the number of animal species present in the food pellet;

[0136] The frequency of prey animals appearing in the food pellets is calculated as follows:

[0137]

[0138] Where: F pi is the frequency of occurrence of the pi-th animal; NP pi is the number of food boluses containing skulls of pi species of animals; NP is the total number of food boluses;

[0139] The formula for calculating the prey intensity of prey animals is as follows:

[0140]

[0141] Where: P pi is the predation intensity of the pi-th animal; N pi is the number of individuals of the pi-th species of animal; N is the total number of individuals of prey animals;

[0142] The biomass ratio of prey animals is calculated as follows:

[0143]

[0144] Where: FB pi is the biomass ratio of the pi-th animal; N pi* is the number of individuals of the pi-th species; B pi is the average weight of the pi-th species of animal; np is the number of prey species.

[0145] Step 11: Calculate the comprehensive index of ecological environment quality in urban plains: Based on the urban plain ecological environment change index system and method based on small mammal survey, calculate the comprehensive index of ecological environment quality in urban plains. The ecological environment quality evaluation of each point in the urban plain area adopts a unified index system for calculation, including ecosystem and biodiversity.

[0146] It covers two primary indicators: vegetation cover index and biodiversity index;

[0147] The vegetation coverage index consists of four secondary indicators, namely, forest index, shrub index, grassland index, and cultivated land index; the biodiversity index consists of four secondary indicators, namely, species diversity index of prey animals, frequency index of prey animals in food pellets, prey intensity index of prey animals, and biomass ratio index of prey animals; each secondary indicator has different calculation parameters:

[0148] The calculation parameters of the secondary indicator forest index are: the coverage area percentage, biomass and vascular plant species richness of tree forests in the region; the calculation parameters of the secondary indicator shrub index are: the coverage area percentage, biomass and vascular plant species richness of shrubs in the region; the calculation parameters of the secondary indicator grassland index are: the coverage area percentage, biomass and vascular plant species richness of grassland in the region; the calculation parameters of the secondary indicator cultivated land index are: the coverage area percentage of cultivated land in the region;

[0149] The calculation parameters of the secondary indicator of species diversity index of prey animals are: species richness of rodents, chiropterans, and laurasia insectivores, and birds; the calculation parameters of the secondary indicator of frequency index of prey animals in food pellets are: frequency of occurrence of rodents, chiropterans, and laurasia insectivores, and birds in food pellets; the calculation parameters of the secondary indicator of predator predation intensity index are: predation intensity of rodents, chiropterans, and laurasia insectivores, and birds; the calculation parameters of the secondary indicator of biomass ratio index of prey animals are: biomass ratio of rodents, chiropterans, and laurasia insectivores, and birds;

[0150] The comprehensive index of ecological environment quality in urban plain areas is calculated according to formula (1):

[0151]

[0152] Where:

[0153] UPTEEI is the comprehensive index of ecological environment quality in urban plain areas;

[0154] ω i is the weight of the i-th first-level indicator;

[0155] n is the number of first-level indicators;

[0156] m i is the number of secondary indicators under the i-th primary indicator;

[0157] ω ij is the weight of the jth secondary indicator under the i-th primary indicator;

[0158] l ij is the number of parameters calculated under the jth secondary indicator under the i-th primary indicator;

[0159] ω ijk is the weight of the kth calculation parameter under the jth secondary indicator under the i-th primary indicator;

[0160] I ijk is the evaluation value of the kth calculation parameter under the jth secondary indicator under the ith primary indicator;

[0161] i is the first-level indicator number;

[0162] j is the secondary indicator number;

[0163] k is the number of the evaluation value of the calculation parameter;

[0164] The evaluation value of the calculation parameter is calculated according to formula (2):

[0165]

[0166] Where:

[0167] I ijk is the evaluation value of the kth calculation parameter under the jth secondary indicator under the ith primary indicator;

[0168] X ijk is the measured or estimated value of the kth calculation parameter under the jth secondary indicator under the ith primary indicator;

[0169] X max(ijk) is the maximum value of the kth calculation parameter under the jth secondary indicator under the ith primary indicator during the evaluation period;

[0170] X min(ijk) It is the minimum value of the kth calculation parameter under the jth secondary indicator under the ith primary indicator within the evaluation period;

[0171] In this embodiment, the specific urban plain area ecological environment quality comprehensive index evaluation index system is as follows:

[0172] Table 7

[0173]

[0174]

[0175] In this embodiment:

[0176] The forest index is calculated according to formula (1.1):

[0177] I for =0.50×I sfor +0.30×I biofor +0.20×I spcifor (1.1)

[0178] Where:

[0179] I for is the calculated value of the forest index;

[0180] I sfor is the evaluation value of forest coverage ratio, and the evaluation method is calculated according to formula (2);

[0181] I biofor is the evaluation value of forest biomass, and the evaluation method is calculated according to formula (2);

[0182] I spcifor is the evaluation value of forest species richness, and the evaluation method is calculated according to formula (2);

[0183] The shrub index is calculated according to formula (1.2):

[0184] I shrub =0.50×I sshrub +0.30×I bioshrub +0.20×I spcihrub (1.2)

[0185] Where:

[0186] I shrub is the calculated value of the shrub index;

[0187] I sshrub is the evaluation value of the percentage of shrub coverage area, and the evaluation method is calculated according to formula (2);

[0188] I bioshrub is the evaluation value of shrub biomass, and the evaluation method is calculated according to formula (2);

[0189] I spcihrub is the evaluation value of shrub species richness, and the evaluation method is calculated according to formula (2);

[0190] The grassland index is calculated according to formula (1.3):

[0191] I grass =0.50×I sgrass+0.30×I biosgrass +0.20×I spcigrass (1.3)

[0192] Where:

[0193] I grass is the calculated value of grassland index;

[0194] I sgrass is the evaluation value of the percentage of grassland coverage area, and the evaluation method is calculated according to formula (2);

[0195] I biosgrass is the evaluation value of grassland biomass, and the evaluation method is calculated according to formula (2);

[0196] I spcigrass is the evaluation value of grassland species richness, and the evaluation method is calculated according to formula (2);

[0197] The evaluation value of the cultivated land index is calculated according to formula (1.4):

[0198] I cul =1×I scul (1.4)

[0199] Where:

[0200] I cul is the evaluation value of the cultivated land index;

[0201] I scul is the evaluation value of the proportion of cultivated land coverage, and the evaluation method is calculated according to formula (2);

[0202] The species diversity index of prey animals is calculated according to formula (1.5):

[0203] I spciprey =0.70×I spciRodentia +0.10×I spciChiroptera +0.10×I spciInsectivora +0.10×I spciAves (1.5)

[0204] Where:

[0205] I spciprey is the species diversity index of prey animals;

[0206] I spciRodentia is the evaluation value of rodent species richness, and the evaluation method is calculated according to formula (2);

[0207] I spciChiroptera is the evaluation value of Chiroptera species richness, and the evaluation method is calculated according to formula (2);

[0208] IspciInsectivora is the evaluation value of the species richness of Laurasia Insectivora, and the evaluation method is calculated according to formula (2);

[0209] I spciAves is the evaluation value of bird species richness, and the evaluation method is calculated according to formula (2);

[0210] The frequency index of prey animals in the pellets is calculated according to formula (1.6):

[0211] I Fprey =0.70×I FRodentia +0.10×I FChiroptera +0.10×I FInsectivora +0.10×I FAves (1.6)

[0212] Where:

[0213] I Fprey is the species diversity index of prey animals;

[0214] I FRodentia is the evaluation value of the frequency index of rodents in the food pellets, and the evaluation method is calculated according to formula (2);

[0215] I FChiroptera is the evaluation value of the frequency index of Chiroptera in food pellets, and the evaluation method is calculated according to formula (2);

[0216] I FInsectivora is the evaluation value of the frequency index of Laurasia in the pellets, and the evaluation method is calculated according to formula (2);

[0217] I FAves is the evaluation value of the frequency index of birds appearing in the pellets, and the evaluation method is calculated according to formula (2);

[0218] The prey intensity index of prey animals is calculated according to formula (1.7):

[0219] I predation intensity =0.70×I predation intensity Rodentia +0.10×I predation intensity Chiroptera +0.10×I predation intensity Insectivora +0.10×I predation intensity Aves (1.7)

[0220] Where:

[0221] I predation intensity is the predation intensity index of the prey animal;

[0222] I predation intensity Rodentia is the evaluation value of the rodent predation intensity index, and the evaluation method is calculated according to formula (2);

[0223] I predation intensity Chiroptera is the evaluation value of the predation intensity index of Chiroptera, and the evaluation method is based on formula (2):

[0224] calculate;

[0225] I predation intensity Insectivora is the evaluation value of the predation intensity index of Laurasia, and the evaluation method is calculated according to formula (2);

[0226] I predation intensity Aves is the evaluation value of the bird predation intensity index, and the evaluation method is calculated according to formula (2);

[0227] The biomass ratio index of prey animals is calculated according to formula (1.8):

[0228] I F pre bio =0.70×I F pre bio Rodentia +0.10×I F pre bio Chiroptera +0.10×I F pre bio Insectivora +0.10×I F pre bio Aves (1.8)

[0229] Where:

[0230] I F pre bio is the predation intensity index of the prey animal;

[0231] I F pre bio Rodentia is the evaluation value of the rodent biomass ratio index, and the evaluation method is calculated according to formula (2);

[0232] I F pre bio Chiroptera is the evaluation value of the Chiroptera biomass ratio index, and the evaluation method is calculated according to formula (2);

[0233] I F pre bio Insectivora is the evaluation value of the Laurasia Insectivora biomass ratio index, and the evaluation method is calculated according to formula (2);

[0234] I F pre bio Aves is the evaluation value of the bird biomass ratio index, and the evaluation method is calculated according to formula (2);

[0235] Step 12: Compare the changes in the ecological environment quality of different regions in the same period based on the comprehensive index of the ecological environment quality of urban plains in different regions; or compare the comprehensive index of the ecological environment quality of urban plains in the same region in different years to determine the changes in the ecological environment of urban plains. In this embodiment, according to the specific value of the comprehensive index of the ecological environment quality of urban plains, the comprehensive index of the ecological environment quality of each urban plain is divided into 7 levels, namely 1, 2, 3, 4, 5, 6 and 7, as shown in the table below. The ecological environment quality of urban plains can be graded according to specific circumstances.

[0236] Table 8

[0237]

[0238] Finally, it should be noted that the above is only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred arrangement scheme, a person skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for monitoring changes in the ecological environment of urban plains based on small mammal surveys, characterized in that: The following steps are involved: Step 1: Determine the collection point for long-eared owl pellets; Step 2: Obtain the coverage area percentage and biomass of forests, bushes, grasslands, and cultivated land within the predation range: Take the long-eared owl pellet collection point as the center point and 10 km as the radius to obtain the long-eared owl's predation range. Obtain the coverage area percentage and biomass of forests, bushes, grasslands, and cultivated land in the region through remote sensing interpretation once a year; Step 3: Obtain the species richness of vascular plants in forests, shrubs, and grasslands within the predation range: In July and August of the year following the long-eared owl observation, set up vegetation survey plots within a 3-kilometer range with the long-eared owl pellet collection point as the center point, including types: grassland, shrubs, and tree forests, investigate and record basic information in the plots, and obtain the species richness of vascular plants in forests, shrubs, and grasslands in the area; Step 4: Food pellet collection: From November of the observation year to March of the following year, food pellets were collected every 2 weeks; Step 5: Food pellet separation: In a petri dish, separate each bone; Step 6: Count the number of animals eaten by the pellets: determine the number of small mammals eaten based on the number of maxillary and mandibular pairs obtained; determine the number of birds eaten based on the number of undigested beaks, skulls or claws; Step 7: Species identification of small mammals: After determining the number of animals, identify the order to which the small mammals belong; and identify the species of rodents, chiropterans, and laurasiana insectivores to the species level; Step 8: Identify the prey birds by species and order; Step 9: Establish a weight query table of prey caught by long-tailed owls through literature search; Step 10: Based on the work of steps 4 to 9, calculate the biodiversity index measurement parameters: species richness of prey animals, frequency of prey animals in food pellets, intensity of prey animals being preyed on, and biomass ratio of prey animals; Step 11: Calculate the comprehensive index of ecological environment quality in urban plain areas: It covers two primary indicators: vegetation cover index and biodiversity index; The vegetation coverage index consists of four secondary indicators, namely, forest index, shrub index, grassland index, and cultivated land index; the biodiversity index consists of four secondary indicators, namely, species diversity index of prey animals, frequency index of prey animals in food pellets, prey intensity index of prey animals, and biomass ratio index of prey animals; each secondary indicator has different calculation parameters: The calculation parameters of the secondary indicator forest index are: the coverage area percentage, biomass and vascular plant species richness of tree forests in the region; the calculation parameters of the secondary indicator shrub index are: the coverage area percentage, biomass and vascular plant species richness of shrubs in the region; the calculation parameters of the secondary indicator grassland index are: the coverage area percentage, biomass and vascular plant species richness of grassland in the region; the calculation parameters of the secondary indicator cultivated land index are: the coverage area percentage of cultivated land in the region; The calculation parameters of the secondary indicator of species diversity index of prey animals are: species richness of rodents, chiropterans, and laurasia insectivores, and birds; the calculation parameters of the secondary indicator of frequency index of prey animals in food pellets are: frequency of occurrence of rodents, chiropterans, and laurasia insectivores, and birds in food pellets; the calculation parameters of the secondary indicator of predator predation intensity index are: predation intensity of rodents, chiropterans, and laurasia insectivores, and birds; the calculation parameters of the secondary indicator of biomass ratio index of prey animals are: biomass ratio of rodents, chiropterans, and laurasia insectivores, and birds; The comprehensive index of ecological environment quality in urban plain areas is calculated according to formula (1): Where: UPTEEI is the comprehensive index of ecological environment quality in urban plain areas; ω i is the weight of the i-th first-level indicator; n is the number of first-level indicators; m i is the number of secondary indicators under the i-th primary indicator; ω ij is the weight of the jth secondary indicator under the i-th primary indicator; l ij is the number of parameters calculated under the jth secondary indicator under the i-th primary indicator; ω ijk is the weight of the kth calculation parameter under the jth secondary indicator under the i-th primary indicator; I ijk is the evaluation value of the kth calculation parameter under the jth secondary indicator under the ith primary indicator; i is the first-level indicator number; j is the secondary indicator number; k is the number of the evaluation value of the calculation parameter; The evaluation value of the calculation parameter is calculated according to formula (2): Where: I ijk is the evaluation value of the kth calculation parameter under the jth secondary indicator under the ith primary indicator; X ijk is the measured or estimated value of the kth calculation parameter under the jth secondary indicator under the ith primary indicator; X max(ijk) is the maximum value of the kth calculation parameter under the jth secondary indicator under the ith primary indicator during the evaluation period; X min(ijk) It is the minimum value of the kth calculation parameter under the jth secondary indicator under the ith primary indicator within the evaluation period; Step 12: Compare the changes in ecological environment quality in different regions during the same period based on the comprehensive ecological environment quality index of urban plain areas in different regions; or compare the comprehensive ecological environment quality index of urban plain areas in the same region in different years to determine the changes in the ecological environment of urban plain areas.

2. The method for monitoring ecological environment changes in urban plains based on small mammal surveys according to claim 1 is characterized by: In step 1, a point where long-eared owls are stably distributed for a long time is selected as a candidate point for collecting food pellets; the point where long-eared owls are stably distributed for a long time is a place where long-eared owls appear for two consecutive years according to bird watching record data; Then, we went to the alternative collection points for long-eared owl food pellets to conduct site surveys, and selected some of the alternative points as collection points for long-eared owl food pellets, with the distance between the two collection points being required to be more than 20 kilometers.

3. The method for monitoring ecological environment changes in urban plains based on small mammal surveys according to claim 1 is characterized by: In step 2, biomass calculation: The biomass of the forest is calculated according to formula (3): biofor=4.031×ln(LAI)+5.036 (3) Where: LAI is the leaf area index; biofor is the forest biomass; The biomass of the shrub is calculated according to formula (4): bioshrub =4.031×ln(LAI)+5.036 (4) Where: bioshrub is the shrub biomass; The biomass of grassland is calculated according to formula (5): biosgrass = (420.7×RVI+53.594) / 10000 (5) Where: RVI is the ratio vegetation index; biosgrass is the grassland biomass; The normalized vegetation index of Landsat images calculated based on GEE is as follows: Where: NDVI is the normalized difference vegetation index; ρ nir is the reflectivity in the near-infrared band; ρ red is the reflectivity of red light band; The ratio vegetation index of Landsat images is calculated based on GEE as shown in formula (7): The vegetation leaf area index is calculated according to formula (8): LAI=5.724×NDVI-1.536 (8).

4. The method for monitoring ecological environment changes in urban plains based on small mammal surveys according to claim 1 is characterized by: In step three, the basic information recorded in the sample plot includes: vegetation type, vegetation composition, canopy density, altitude, slope, aspect, coverage, tree species, breast diameter, tree height, ground diameter, number of clusters, and vitality; the vascular plant species richness adopts the number of vascular plant species occurring in the area.

5. The method for monitoring ecological environment changes in urban plains based on small mammal surveys according to claim 1 is characterized by: In step 4, before collecting the food pills, prepare the food pill collection tools: including plastic gloves, 95% alcohol, ziplock bags, label paper, markers, purchased video surveillance systems, field investigation record logs, and vernier calipers.

6. The method for monitoring ecological environment changes in urban plains based on small mammal surveys according to claim 1 is characterized by: In step five, place the individual pellets in a petri dish, add 95% alcohol, and separate each bone using forceps.

7. The method for monitoring ecological environment changes in urban plains based on small mammal surveys according to claim 1 is characterized by: In step seven, the order of small mammals is determined based on the regional small mammal suborder retrieval table, based on the bones and incisor position of each animal. Based on the tooth pattern of the maxillary teeth and comparing the morphology of the skull in the atlas, a classification retrieval table is established to identify the species.

8. The method for monitoring ecological environment changes in urban plains based on small mammal surveys according to claim 1 is characterized by: In step eight, birds are identified to orders based on remaining beaks, bones, and feathers.

9. The method for monitoring ecological environment changes in urban plains based on small mammal surveys according to claim 1 is characterized by: In step 10: the species richness of prey animals is measured by the number of animal species present in the food pellet; The frequency of prey animals appearing in the food pellets is calculated as follows: Where: F pi is the frequency of occurrence of the pi-th animal; NP pi is the number of food boluses containing skulls of pi species of animals; NP is the total number of food boluses; The formula for calculating the prey intensity of prey animals is as follows: Where: P pi is the predation intensity of the pi-th animal; N pi is the number of individuals of the pi-th species of animal; N is the total number of individuals of prey animals; The biomass ratio of prey animals is calculated as follows: Where: FB pi is the biomass ratio of the pi-th animal; N pi* is the number of individuals of the pi-th species; B pi is the average weight of the pi-th species of animal; np is the number of prey species.

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