Environmental changes in biodiversity hotspot ecosystems of
South Ecuador: RESPonse and feedback effECTs (FOR2730)

Abstract:

Habitat loss and landscape fragmentation are important drivers of changes in biodiversity. In fragmented landscapes, bird species are able to use multiple forest patches that may therefore share an important portion of the regional biodiversity. In turn, these patches are linked through their shared bird diversity (i.e. species-habitat networks). Identifying the importance of nodes (e.g. forest patches) in species-habitat networks is increasingly important to improve conservation planning. Within this network approach, the relative importance of patches for birds can be identified via centrality indices-measures of the magnitude of shared bird diversity of patches across the entire network (i.e. patch centrality). Here, we tested for changes in patch centrality within bird species-patch networks of two habitat guilds, forest specialists and generalists, in relation to patch area, patch shape irregularity and within-patch habitat characteristics across 15 Polylepis woodland patches in a páramo landscape of southern Ecuador. Patch centrality for forest specialists decreased with greater influence of surrounding páramo plants, i.e. an increasing proportion of bunch-grasses and small shrubs, in the within-patch habitat and was unaffected by either patch area or patch shape irregularity. On the other hand, patch centrality for generalists was positively influenced by patch shape irregularity but was unaffected by patch area or the influence of surrounding páramo plants in the within-patch habitat. Patch centrality reveals that the relative importance of Polylepis woodlands lies in their habitat quality. Forest specialists are dependent on mature Polylepis woodland patches, while generalists benefit from the natural irregular shape of the woodlands. Finally, a species-habitat network approach facilitates the recognition of important Polylepis patches and their characteristics for conservation of the Andean bird community at a landscape scale.

Abstract:

Habitat loss and landscape fragmentation are important drivers of changes in biodiversity. In fragmented landscapes, bird species are able to use multiple forest patches that may therefore share an important portion of the regional biodiversity. In turn, these patches are linked through their shared bird diversity (i.e. species-habitat networks). Identifying the importance of nodes (e.g. forest patches) in species-habitat networks is increasingly important to improve conservation planning. within this network approach, the relative importance of patches for birds can be identified via centrality indices-measures of the magnitude of shared bird diversity of patches across the entire network (i.e. patch centrality). here, we tested for changes in patch centrality within bird species-patch networks of two habitat guilds, forest specialists and generalists, in relation to patch area, patch shape irregularity and within-patch habitat characteristics across 15 Polylepis woodland patches in a páramo landscape of southern Ecuador. Patch centrality for forest specialists decreased with greater influence of surrounding páramo plants, i.e. an increasing proportion of bunch-grasses and small shrubs, in the within-patch habitat and was unaffected by either patch area or patch shape irregularity. On the other hand, patch centrality for generalists was positively influenced by patch shape irregularity but was unaffected by patch area or the influence of surrounding páramo plants in the within-patch habitat. Patch centrality reveals that the relative importance of Polylepis woodlands lies in their habitat quality. Forest specialists are dependent on mature Polylepis woodland patches, while generalists benefit from the natural irregular shape of the woodlands. Finally, a species-habitat network approach facilitates the recognition of important Polylepis patches and their characteristics for conservation of the Andean bird communityat a landscape scale.

Abstract:

Atmospheric carbon (CO2) exchange, evapotranspiration (ET) processes, and their interactions with climatic drivers across tropical alpine grasslands are poorly understood. This lack of understanding is particularly evident for the páramo, the highest vegetated frontier in the northern Andes, the main source of water for inter-Andean cities, and a large carbon storage area. Studies of CO2 and ET fluxes via the standard Eddy Covariance (EC) technique have never been applied to this region, limiting the understanding of diurnal / nocturnal exchanges and budget estimations. In this paper, we report the first EC analysis conducted on the Andean páramo (3765?m a.s.l.); this analysis measured CO2, ET, and micrometeorological variables over two years (2016–2018) to understand their interactions with climatic / biophysical controls. The páramo was found to be a source of CO2 and exhibited a net positive exchange (mean = +99?±?30 gC m?2 per year). The light-responses of net CO2 exchange and the primary productivity were correlated and model-parameterized. Evapotranspiration was 635?±?9?mm per year (51% of the annual rainfall total), and we obtained crop coefficients for the dominant vegetation (Tussock grass) based on reference-ET models FAO56 and ASCE-ERWI (0.90 and 0.78, respectively). We also compared our results to those from other high-altitude (alpine) and high-latitude grasslands (tundra). Finally, we demonstrate that our measurement period is representative of the páramo’s longer-term climate dynamics. Our investigation contributes to the body of knowledge on the land surface-atmosphere processes of the tropical Andes and supports decision-making about ecosystem services management and the preservation of this vulnerable biome.

Abstract:

The relative importance of catchment's water provenance and flow paths varies in space and time, complicating the conceptualization of the rainfall-runoff responses. We assessed the temporal dynamics in source areas, flow paths, and age by End Member Mixing Analysis (EMMA), hydrograph separation, and Inverse Transit Time Proxies (ITTPs) estimation within a headwater catchment in the Ecuadorian Andes. Twenty-two solutes, stable isotopes, pH, and electrical conductivity from a stream and 12 potential sources were analyzed. Four end-members were required to satisfactorily represent the hydrological system, i.e., rainfall, spring water, and water from the bottom layers of Histosols and Andosols. Water from Histosols in and near the riparian zone was the highest source contributor to runoff throughout the year (39% for the drier season, 45% for the wetter season), highlighting the importance of the water that is stored in the riparian zone. Spring water contributions to streamflow tripled during the drier season, as evidenced by geochemical signatures that are consistent with deeper flow paths rather than shallow interflow through Andosols. Rainfall exhibited low seasonal variation in this contribution. Hydrograph separation revealed that 94% and 84% is preevent water in the drier and wetter seasons, respectively. From low-flow to high-flow conditions, all the sources increased their contribution except spring water. The relative age of stream water decreased during wetter periods, when the contributing area of the riparian zone expands. The multimethod and multitracer approach enabled to closely study the interchanging importance of flow processes and water source dynamics from an interannual perspective.

Abstract:

Geographic Information Systems and Remote Sensing are important contributors to Sustainable Forestry Management Plans. Remote sensing techniques for image interpretation provides the means to extract valuable information that could be expensive and time-consuming to obtain through field observations (Franklin et al. 2001). Spatial Products derived from the interpretation of airborne and satellite borne images feed Geographic Information Systems to develop strategies and methodologies for resource management, harvest planning, fire management, map production, and model predictions. (Yusmah et al. 2015) This study has three important objectives: to test the feasibility of template matching for the identification of single pine tree crowns, to conduct a delineation of pine plantations using relational features and to evaluate how single tree crown size affects the accuracy of the proposed method. Templates of single trees were produced in the software eCognition Developer. The sampling process comprised the random selection of 3000 single pine trees in 7 different test sites (test sites were grouped in 3 categories according to the single tree sizes). A first rule set to detect single tree crowns was developed in eCognition Developer, using three different template groups (4, 8 and 16 templates). Through an analysis of variance, the number of single tree crowns detected was compared for the different template groups. Using a second rule set in eCognition, the template matching algorithm combined with relational, spectral and contextual information were applied to delineate pine plantation areas. An accuracy assessment was performed in the test sites for all thematic classes identified. Finally, an Analysis of Variance evaluated the influence of single tree crown size on the overall accuracy. Potential applications and improvements to the proposed methodology for single tree crown detection and plantation delineation are proposed at the end of the document.

Abstract:

As a consequence of the remote location of the Andean páramo is knowledge on their hydrologic functioning limited, notwithstanding this alpine tundra ecosystem act as water towers for a large fraction of the society. Given the harsh environmental conditions in this region is year-round monitoring cumbersome, and it would be beneficially if the monitoring needed for the understanding of the rainfall-runoff response could be limited in time. To identify the hydrological response and the effect of temporal monitoring a nested (n?=?7) hydrological monitoring network was set up in the Zhurucay catchment (7.53?km2), south Ecuador. The research questions were: (1) can event sampling provide similar information in comparison to continuous monitoring, and (2) if so, how many events are needed to achieve a similar degree of information? A subset of 34 rainfall runoff events was compared to monthly values derived from a continuous monitoring scheme from December 2010 to November 2013. Land cover and physiographic characteristics were correlated with eleven hydrological indices. Results show that despite some distinct differences between event and continuous sampling, both datasets reveal similar information; more in particular the monitoring of a single event in the rainy season provides the same information as continuous monitoring, while during the dry season 10 events ought to be monitored.

Abstract:

This study focuses on the investigation of the mean transit time (MTT) of water and its spatial variability in a tropical high-elevation ecosystem (wet Andean páramo). The study site is the Zhurucay River Ecohydrological Observatory (7.53?km2) located in southern Ecuador. A lumped parameter model considering five transit time distribution (TTD) functions was used to estimate MTTs under steady-state conditions (i.e., baseflow MTT). We used a unique data set of the ?18O isotopic composition of rainfall and streamflow water samples collected for 3 years (May 2011 to May 2014) in a nested monitoring system of streams. Linear regression between MTT and landscape (soil and vegetation cover, geology, and topography) and hydrometric (runoff coefficient and specific discharge rates) variables was used to explore controls on MTT variability, as well as mean electrical conductivity (MEC) as a possible proxy for MTT. Results revealed that the exponential TTD function best describes the hydrology of the site, indicating a relatively simple transition from rainfall water to the streams through the organic horizon of the wet páramo soils. MTT of the streams is relatively short (0.15–0.73 years, 53–264 days). Regression analysis revealed a negative correlation between the catchment's average slope and MTT (R2?=??0.78, p?<?0.05). MTT showed no significant correlation with hydrometric variables, whereas MEC increases with MTT (R2?=??0.89, p?<?0.001). Overall, we conclude that (1) baseflow MTT confirms that the hydrology of the ecosystem is dominated by shallow subsurface flow; (2) the interplay between the high storage capacity of the wet páramo soils and the slope of the catchments provides the ecosystem with high regulation capacity; and (3) MEC is an efficient predictor of MTT variability in this system of catchments with relatively homogeneous geology.

Abstract:

Im Páramo der ecuadorianischen Anden wurden in einer Höhe zwischen 3000 m und 4000 m Plantagen mit Pinus patula angelegt. Dadurch wurden im Páramo normalerweise nicht vorkommende Ektomykorrhizapilze eingeführt. Mithilfe morphologischer und molekularer Methoden wurden die Ektomykorrhiza-Arten in drei Plantagen in der Nähe von Cuenca untersucht. Insgesamt wurden fünf verschiedene Ektomykorrhizapilze gefunden, von denen drei bis auf die Art bestimmt werden konnten: Thelephora terrestris, Suillus luteus, Inocybe jacobi, eine Sebacina-Art und eine nicht identifizierte Art. Thelephora terrestris war in allen drei Plantagen die am häufigsten vorkommenden Ektomykorrhiza-Art. Die Ektomykorrhizagemeinschaft dieser Plantagen ist also sehr artenarm im Vergleich zu natürlichen Standorten. Diese Beobachtung wird von anderen Studien in Kiefernplantagen der südlichen Hemisphäre bestätigt.

Abstract:

National parks are an important tool for conserving biodiversity, particularly in areas of high biodiversity and endemism such as the tropical Andes. However, national parks often face a variety of stressors related to recreation, road construction and illegal extraction of natural resources. Unfortunately, the influence of these stressors for biodiversity is rarely well documented. Cajas National Park in Ecuador is no exception. Despite being traversed by the Cuenca-Molleturo-Naranjal road, effects of the road construction on biodiversity have not been determined. We therefore assessed the influence of road proximity on bird species richness and abundance as well as composition of bird habitat groups in Cajas National Park using transect walks at 25 m and 250 m distance to the road (overall 18 transects, each 1 km length). In total, we recorded 1110 individuals of 28 páramo bird species. Overall species richness did not differ between transects near and far from the road. Nevertheless, the average abundance of shrubby páramo species was significantly higher far from the road than near the road (Far = 36, Near = 25). Moreover, we found a tendency towards differences in the composition of bird habitat groups between transects near and far from the road. One aspect potentially driving the observed patterns was the increasing proportion of planted non-native woody tree species within páramo grassland near the road, which may have caused reduced abundances of shrubby páramo bird species there. While roads represented a clear impact on the composition of bird species in the páramo, the major effect seems to be driven by the introduction of non- native plant species along the roadside. In order to reduce the impact of roads to a minimum, we suggest that park managers should control the introduction of such plant species.

Abstract:

In times of climate change and devastation, the conservation of biodiversity is an important issue. The formation of a mycorrhiza plays a very important role. The arbuscular mycorrhiza is a mutualistic symbiosis between fungi and plant roots. The arbuscular mycorrhizal fungi represent a monophyletic group, the Glomeromycota, which probably have a common ancestor with the Asco-and Basidiomycota. The arbuscular mycorrhiza is characterized by an enormous spreading. It is found in all climates. The vast majority of tropical plants form an arbuscular mycorrhiza, including plants in the Páramo, a type of vegetation in the humid tropical high Andes of South America above the treeline. In this study, root material from the Páramo-vegetation in Cajanuma in South Ecuador was examined. The analysis can be divided into two parts, the morphological and genetic analyses. Concerning the morphology the root samples were analysed under the light microscope. In 16 of 20 samples colonization with arbuscular mycorrhizal fungi was detected. Exactly these 16 samples also showed fungi belonging to the group of dark sepatate endophytes (DSE) which are likely representatives of the Ascomycota. In the context of genetic analyses arbuscular mycorrhizal fungi have been analysed with molecular methods sequencing part of the 18S rDNA. For the identification of fungi, which do not belong to the Glomeromycota, a part of the ITS-region of the DNA has been studied and sequenced. The sequences of arbuscular mycorrhizal fungi belong to families of Glomeraceae and Acaulosporaceae. In comparison with other investigations it can be assumed that the Páramo in Cajanuma has its own AMF community. The sequences of the Ascomycota all belong to the order of the Helotiales. By comparing the results to other investigations it could be demonstrated, that the dark septate endophytes survive under several climatic conditions. Furthermore they probably play an important role in the supply of nutrients. In this work, the dark septate endophytes show a greater range of species than the arbuscular mycorrhizal fungi. That possibly indicates a higher diversity in the Ascomycota than in the Glomeroycota in the Páramo-vegetation in Cajanuma. In order to confirm this hypothesis, a far greater data base is required. This data base will be the key to maintaining biodiversity. It ensures a better understanding of fungi and their interactions. Through this understanding, new approaches to protect biodiversity can be created.

Abstract:

Despite the dominance of grasslands during the last glacial period, especially in South America, the highly uniform morphology of Poaceae pollen grains has so far allowed only very few palynological studies based on Poaceae pollen. In our study we compare two methods of distinguishing between South American grassland ecosystems based on quantitative morphology of Poaceae pollen grains. We investigated data sets from Pa´ramo in southern Ecuador, Campos de Altitude and Campos in south-eastern and southern Brazil as well as data sets from the Pampa in Argentina by measuring the pollen grain length, grain width, pore diameter and annulus width. Firstly we investigated the potential influence of chemical treatment of pollen grains on pollen grain size as well as the measurement setting for defining the boundary conditions for using Poaceae pollen grains in a palaeoecological investigation. Finally the measured pollen grain parameters were analyzed by comparison of average grain length using statistical tests. This approach reveals highly significant differences in average grain size between all grassland ecosystems. Assuming that a certain grain size range can be assigned to a certain Poaceae taxon, conclusions about differences and similarities in taxa composition can be derived. We used two methods of multivariate data analysis. One uses the pollen grain parameters directly for a Principle Component Analysis (PCA). The other is an already established method in grassland ecology which defines parameter based pollen grain types to investigate similarities between grassland ecosystems. Both approaches confirm the results of the grain length analysis. In this work we demonstrate that the method we developed has the potential to provide acquisition of so far inaccessible information on spatial and temporal patterns and dynamics of South American grasslands.

Abstract:

We reconstructed the palaeoenvironmental conditions of the last ca. 8000 years in the Tres Lagunas region of the Quimsacocha volcanic basin (ca. 3800 m a.s.l.) in the southwestern Ecuadorian Andes by means of a pollen and charcoal record. Sediment deposits and pollen taxa reflect warm and possibly drier conditions in the early to mid-Holocene. The late Holocene undergoes several warm and cold-phases of which the most prominent one was the Little Ice-Age which is characterised by a marked increase of taxa that correspond to cold and moist conditions. As charcoal can be recorded since the early to mid-Holocene and Polylepis underwent several phases of degradation and re-establishment in the region, the presence of human influence might be dated back to this time.

Abstract:

We reconstructed the palaeoenvironmental conditions of the last ca. 8000 years in the Tres Lagunas region of the Quimsacocha volcanic basin (ca. 3800 m a.s.l.) in the southwestern Ecuadorian Andes. By means of a pollen and charcoal record, we analysed vegetation, fire, and climate history of this area, which is sensitive to climatic changes of both the Pacific as well as of the eastern Andes and Amazon region. Sediment deposits, pronounced increase of pollen and charcoal concentrations, and pollen taxa reflect warmer and drier conditions in the early to mid-Holocene (~8000 to 3900 cal B.P.). During the late Holocene (2250 to -57 cal B.P.), 5 warm and cold-phases occurred at Quimsacocha. The most prominent cold phase possibly corresponds to the globally recognized Little Ice-Age (LIA; ~600 to 100 cal B.P.). The cold phase signal at Quimsacocha was characterized by a higher abundance of Poaceae, Isoëtes and Gentianella, which favour cold and moist conditions. Frequent charcoal particles can be recorded since the early to mid-Holocene (~7600 B.P.). The high Andean tree species Polylepis underwent several phases of degradation and re-establishment in the basin, which can indicate the use of fire by pre-Columbian settlers to enhance the growth of preferred herb species. The Tres Lagunas record suggests that human populations have been influencing the environment around Quimsacocha since the last ca. 8,000 years.

Abstract:

Based on 5 pollen records from locations between ca. 2700 and 3300 masl in the Podocarpus National Park (PNP) area (ca. 4° S and 79° W) within the Andean depression region in southern Ecuador, we reconstructed and visualized upper forest line (UFL) dynamics and past vegetation changes since the last glacial maximum (LGM). Estimates of altitudinal ranges of past UFL shifts in the study area allowed reconstructing past changes of forest and páramo expansion in the study region. During the LGM, the UFL position in the PNP area was at least ca. 700 m lower in the northernmost part and ca. 250 m further south compared to today. Glaciers covered the central PNP at this time, while deglaciation completed with the beginning of the Holocene. Throughout the recorded time UFL shifts and vegetation changes in the study area showed considerable local differences. This can be explained by locally differing vegetation compositions and climatic conditions, but especially during early to late Holocene times also by human disturbances. Only during the earliest Holocene and mid-Holocene the UFL in the central and southern PNP areas reached slightly higher elevations up to 200 m above the present position. The UFL in the PNP area shifted altitudinally over a shorter interval compared to other sites outside the depression. This difference may be caused by the study regions relatively low mountain elevations, wet climatic conditions, different and diverse vegetation pattern as well as by the corresponding vegetation response to climatic changes. The high complexity and heterogeneity of Andean habitats are assumed to be responsible for the variety in altitudinal distribution and compositional changes of vegetation. In the PNP area and the Andean depression region temperature seems to be less important for the UFL and vegetation changes than in other regions of the northern Andes. Instead we assume that other drivers, e.g. precipitation and wind, may be much more important for the developments in our study region.

Abstract:

To study vegetation/modern pollen rain relationship a total of 41 pollen traps have been installed for one year on an altitudinal transect between 1800 and 3185 ma.s.l. elevation in the montane forest and páramo vegetation type of the ECSF research area, located between Loja and Zamora in the southeastern Ecuadorian Andes. Results revealed that the altitudinal vegetation gradient of lower montane forest, upper montane forest, subpáramo and páramo is well reflected in the modern pollen rain data. Principal component analysis (PCA) on the pollen rain data indicate that a high number of pollen and spore taxa are characteristic for one vegetation type or reflect the altitudinal distribution of genera and families of modern vegetation. However, a considerable number of pollen and spore taxa not representing modern vegetation types were identified as well. Wind dispersal is supposed to be responsible for differences found between plant and pollen distribution patterns. Characteristic pollen and spore taxa for the lower montane forest are Alchornea, Heliocarpus and Hyeronima; for the upper montane forest Cyathea spp., Elaphoglossum ciliatum and Purdiaea nutans; and for the subpáramo Cyperaceae, Ericaceae, Jamesonia and Valeriana. The position of the modern upper timberline in the research area is reflected in the pollen rain by an increase of subpáramo taxa and a decrease of montane forest taxa.