Measures Of Ecological Integrity Research Articles

Spatial and Temporal Dynamics of the Vegetation Cover from the Bijagual Massif, Boyacá, Colombia, during the 1986-2021 Period.

Landscape changes based on spectral responses allow showing plant cover changes through diversity, composition, and ecological connectivity. The spatial and temporal vegetation dynamics of the Bijagual Massif from 1986 to 2021 were analyzed as a measure of ecological integrity, conservation, and territory. The covers identified were high open forest (Hof), dense grassland of non-wooded mainland (Dgnm), a mosaic of pastures and crops (Mpc), lagoons (Lag), and bare and degraded lands (Bdl). The Bijagual Massif has 8574.1 ha. In 1986, Dgnm occupied 42.6% of the total area, followed by Mpc (32.8%) and Hof (24.5%); by 2000, Mpc and Hof increased (43.7 and 28.1%, respectively), while Dgnm decreased (28%); by 2021, Dgnm was restricted to the northeastern zone and continued to decrease (25.2%), Mpc occupied 52.9%, Hof 21.7% and Bdl 0.1%. Of the three fractions of the connectivity probability index, only dPCintra and dPCflux contribute to ecological connectivity. Hof and Dgnm show patches with biota habitat quality and availability. Between 1986 and 2021, Dgnm lost 1489 ha (41%) and Hof 239.5 ha (11%). Mpc replaced various covers (1722.2 ha; 38%) in 2021. Bijagual has a valuable biodiversity potential limited by Mpc. Territorial planning and sustainable agroecological and ecotourism proposals are required due to the context of the ecosystems.

Ecological integrity and conservation challenges in a rapidly changing Arctic: A call for new approaches in large intact landscapes.

Intactness is a commonly used measure of ecological integrity, especially when evaluating conservation status at the landscape scale. We argue that in the large and relatively unfragmented landscapes of the Arctic and sub-Arctic, intactness provides only partial insight for managers charged with maintaining ecological integrity. A recent landscape assessment suggests that 95% of Alaska shows no measured direct or indirect impacts of human development on the landscape. However, the current exceptionally high levels of intactness in Alaska, and throughout the Arctic and sub-Arctic, do not adequately reflect impacts to the region's ecological integrity caused by indirect stressors, such as a rapidly changing climate and the subsequent loss of the cryosphere. Thus, it can be difficult to measure, and manage, some of the conservation challenges presented by the ecological context of these systems. The dominant drivers of change, and their associated ecological and socioeconomic impacts, vary as systems decline in ecological integrity from very high to high, and to intermediate levels, but this is not well understood in the literature. Arctic and sub-Arctic systems, as well as other large intact areas, provide unique opportunities for conservation planning, but require tools and approaches appropriate to unfragmented landscapes undergoing rapid climate-driven ecological transformation. We conclude with possible directions for developing more appropriate metrics for measuring ecological integrity in these systems.

Identifying candidate reference reaches to assess the physical and biological integrity of wadeable streams in different ecoregions and among stream sizes

Abstract Efforts to quantify disturbances to aquatic systems often use landscape-level metrics, presumably linked to ecological integrity, but fewer studies have directly linked ecological integrity to instream habitat, and applied these results to unsampled stream reaches throughout a landscape. We developed a flexible, quantitative approach that characterizes stream impairment across a landscape and identifies least-disturbed stream reaches to serve as benchmarks for high quality physical habitat and ecological integrity. Fish and macroinvertebrate community characteristics, reach-level physical habitat and water quality metrics were summarized in 891 wadeable stream reaches across two ecoregions in Missouri, USA. The influence of reach and water-quality characteristics as well as landscape-level variables on 7 fish and 3 macroinvertebrate community biological indicator metrics was then modeled using boosted regression trees (BRTs). On average, reach-level models explained more variance (25 and 27% in the two ecoregions examined) in biotic metrics than landscape-level models (18% and 20%). Abiotic and biotic associations differed among ecoregions and stream sizes, however, reach-level habitat (e.g., bankfull width/depth ratio, channel incision height) and water quality (e.g., dissolved oxygen, total chlorophyll) were consistently top predictors. At the landscape scale, fish richness in the agriculturally dominated ecoregion increased with decreased fragmentation/flow modification. Invertebrate metrics in the forested ecoregion showed community degradation apparent with crop coverage as low as 8–10% of the riparian zone, while urban impairment, most notably in the agricultural ecoregion, was best detected using invertebrate indicators of biotic integrity and measures of fish trophic ecology. Relationships among landscape-scale variables and reach characteristics identified as top predictors in BRTs also highlighted potential mechanistic relationships among landscape, habitat, and measures of ecological integrity. Using the results of the landscape-level models, estimates for overall ecological integrity were predicted for over 28,000 stream reaches throughout Missouri, and a total of 1423 candidate reference reaches were identified. The objective approach to characterizing stream impairment developed in this study offers specific advantages, including a reach and landscape-level evaluation of human disturbance as well as an inductive, multi-metric determination of ecological integrity.

Tracking environmental stress gradients using three biotic integrity indices: Advantages of a locally-developed traits-based approach

Estuarine and coastal ecosystems are productive and functionally diverse areas that provide a wide range of societal benefits. Along with human exploitative uses comes an array of anthropogenic disturbances that can affect ecological integrity, including changes to the composition and resilience of benthic macroinvertebrate communities. To understand the responses of ecological communities to anthropogenic disturbance and to manage and mitigate effects, indices for assessing the ecological integrity of estuarine and coastal waters have proliferated worldwide. Using data from 84 intertidal sites in Auckland, New Zealand, we evaluated the suitability of two widely used measures of ecological integrity that were developed in USA and Europe, respectively: the Benthic Index of Biotic Integrity (B-IBI) and the AZTI's Marine Biotic Index (AMBI). We then developed a local index based on macrofaunal traits and verified its utility using independent data from >100 additional sites. The local traits based index (TBI), constructed from the richness of macrofaunal taxa in seven functional groups, responded to changes in sediment mud percentage and heavy metal contaminant concentration gradients below international guidelines. The TBI performed better than the indices developed overseas, probably because they were designed to track organic enrichment and hypoxia, which are not the predominant stressors in New Zealand at present. The TBI successfully tracked the stressors that were the most relevant locally and indicated the relative levels of within-group taxonomic richness at various sites. As within-group richness is a component of functional redundancy and ecological resilience, the TBI offers a trifecta of simplicity, robustness and meaningfulness that will facilitate management.

Assessing estuarine benthic quality conditions in Chesapeake Bay: A comparison of three indices

Abstract Legislation in US and Europe has been adopted to determine the ecological integrity of estuarine and coastal waters, including, as one of the most relevant elements, the benthic macroinvertebrate communities. It has been recommended that greater emphasis should be placed on evaluating the suitability of existing indices prior to developing new ones. This study compares two widely used measures of ecological integrity, the Benthic Index of Biotic Integrity (B-IBI) developed in USA and the European AZTI's Marine Biotic Index (AMBI) and its multivariate extension, the M-AMBI. Specific objectives were to identify the frequency, magnitude, and nature of differences in assessment of Chesapeake Bay sites as ‘degraded’ or ‘undegraded’ by the indices. A dataset of 275 subtidal samples taken in 2003 from Chesapeake Bay were used in this comparison. Linear regression of B-IBI and AMBI, accounted for 24% of the variability; however, when evaluated by salinity regimes, the explained variability increased in polyhaline (38%), high mesohaline (38%), and low mesohaline (35%) habitats, remained similar in the tidal freshwater (25%), and decreased in oligohaline areas (17%). Using the M-AMBI, the explained variability increased to 43% for linear regression, and 54% for logarithmic regression. By salinity regime, the highest explained variability was found in high mesohaline and low polyhaline areas (53–63%), while the lowest explained variability was in the oligohaline and tidal freshwater areas (6–17%). The total disagreement between methods, in terms of degraded-undegraded classifications, was 28%, with high spatial levels of agreement. Our study suggests that different methodologies in assessing benthic quality can provide similar results even though these methods have been developed within different geographical areas.

Using calicioid lichens and fungi to assess ecological continuity in the Acadian Forest Ecoregion of the Canadian Maritimes

The ecological continuity of 28 northern hardwoods, spruce–fir (Picea–Abies), eastern hemlock (Tsuga canadensis L. Carrière), and eastern white-cedar (Thuja occidentalis L.), stands in the Canadian Maritimes has been assessed and the sites ranked among 77 stands in the Acadian Forest Ecoregion using an index of ecological continuity based on the total number of calicioid lichens and fungi collected at each site. Distinguished by their tiny (1–2 mm tall) stipitate apothecia, the calicioid lichens and fungi are a natural unit of investigation, with most species dependent on the occurrence of mature forests containing trees of different ages and varied light and temperature regimes. Given that the diversity of microhabitats can be expected to increase over time in an ageing forest and that the calicioid lichens and fungi can be found growing in more of these microhabitats than any other group of species, it is the presence or absence of these species that provides the evidence whether a forest that looks old really is old and has been little disturbed over a long period of time. Among the stands under investigation in the Maritimes, the wilderness areas at French River, Panuke Lake, Margaree River, North River, and Sugarloaf Mountain in Nova Scotia, the Little Tobique cedar stand at Mount Carleton Provincial Park in New Brunswick, and the Townshend Woodlot Natural Area on Prince Edward Island have been assessed as ancient forest sites based on of the presence of more than 15 calicioid species. Described here as the oldest of the old growth, an ancient forest is defined as a fourth category of forest succession following pioneer, seral, and young old-growth forests. Nine young old-growth forests have also been identified in the Acadian Forest Ecoregion of the Canadian Maritimes, as have several seral and pioneer-stage stands. For those stands assigned calicioid index scores of 10 or less, these values are considered accurate reflections of the much modified or secondary nature of these communities as recorded in site descriptions. For those stands that have been modified by the effects of pollution or the spruce budworm, an assessment using an index of ecological continuity is considered as much a measure of ecological integrity as it is of continuity. Key words: calicoid lichens, old-growth forests, biomonitors, lichens, biodiversity, Canadian Maritimes

Using Energy Systems Theory To Define, Measure, and Interpret Ecological Integrity and Ecosystem Health

ABSTRACT Energy systems theory provides a theoretical basis for defining, measuring, and interpreting the concepts of ecological integrity and ecosystem health. Ecological integrity is defined as an emergent property of ecosystems operating at maximum power that can be quantified using validated Energy Systems models. The cumulative empower production (emergy) calculated using these models is proposed as a measure of ecological integrity. Ecological integrity must be interpreted within the context of an ecosystem's position within the relevant hierarchies of organization and cycles of change that control system behavior. The local integrity and health of an ecosystem are normative concepts because they are evaluated relative to a standard or reference state. The underlying emergy signature responsible for generating ecosystem organization provides an expectation for this reference state. Ecosystems also have global integrity, which is manifested as the flexibility to maximize empower over time in the face of changing external forcing functions. Global integrity has no fixed reference but can be evaluated by comparing alternative system designs. Because the maximum empower principle is a general law that applies to all self‐organizing systems on all scales, these definitions for ecological integrity and ecosystem health apply to both natural ecosystems and ecosystems dominated by human activities. Human‐dominated ecosystems with the highest integrity will be those in which the sum of the empower produced by the economy and its supporting ecosystems is close to a maximum.

Towards the assessment of ‘ecological integrity’ in running waters of the United Kingdom

The development of methods to assess ecological integrity of running waters requires integrating physical and chemical parameters, as well as their effects upon biological structure, diversity and processes. River management in the UK has seen the development of a series of quality assessment methodologies with little integration between them. Methods which assess habitat structure in a biologically meaningful way offer the best approach to integrating measures of the effects of physical and chemical processes upon the river environment. Simultaneous measurement of surface flow types (‘flow biotopes’) and habitat structure (‘functional habitats’) showed clear links. These links could form the first stage in the development of a rapid, cost-effective measure of ecological integrity in rivers of the UK

Use of watershed characteristics to select control streams for estimating effects of metal mining wastes on extensively disturbed streams

Impacts of sediments and heavy metals on the biota of streams in the copper-mining district of southwestern Montana were examined by comparing aquatic communities of impacted streams with those of control streams. Control streams were chosen through the use of a technique that identifies similar streams based on similarities in their watershed characteristics. Significant differences between impacted and control sites existed for surface substrate, riparian vegetation, and the number of macroinvertebrate taxa. These results revealed that: (a) chemical and physical habitats at the impacted sites were disrupted, (b) the presence of trout was an inadequate measure of ecological integrity for these sites, and (c) watershed classification based on a combination of mapped terrestrial characteristics provided a reasonable method to select control sites where potential control sites upstream and downstream were unsuitable.